Complex Particles Research Articles

Preparation and Application of High Internal Phase Pickering Emulsion Gels Stabilized by Starch Nanocrystal/Tannic Acid Complex Particles.

Herein, the starch nanocrystal/tannic acid (ST) complex particles, which were prepared based on the hydrogen bond between starch nanocrystal (SNC) and tannic acid (TA), were successfully used to stabilize the HIPPE gels. The optimal TA concentration of the ST complex particles resulted in better water dispersibility, surface wettability, and interfacial activity as compared to SNC. The hydrogen bond responsible for the formation of ST complex particles and subsequent stable emulsions was demonstrated by varying the pH and ionic strength of the aqueous phase. Notably, the HIPPE gels stabilized via the ST complex particles can maintain long-term stability for up to three months. The HIPPEs stabilized via the ST complex particles all displayed gel-like features and had smaller droplets and denser droplet networks than the SNC-stabilized HIPPEs. The rheological behavior of HIPPE gels stabilized via the ST complex particles can be readily changed by tuning the mass ratio of SNC and TA as well as pH. Finally, the prepared HIPPE gels used to effectively protect encapsulated β-carotene against high temperatures and ultraviolet radiation and its controllable release at room temperature were demonstrated. It is anticipated that the aforementioned findings will provide new perspectives on the preparation of Pickering emulsion for delivery systems.

Formation conditions of soy protein isolate-carrageenan complex particles and their stabilization effect on the relationship between structure and rheology of emulsions

This study investigated the formation conditions of the soy protein isolate (SPI)/κ-carrageenan (κCG) complex particles (SCP) and their stabilization effect on the structure and rheology of emulsions over the range of SCP concentration (Cp, 0.5%–2.5%, w/v) and oil phase content (φ, 10%–60%, v/v). By conducting turbidity titration of SPI/κCG mixtures with different ratios and ionic strengths, we observed the formation of soluble complexes in all samples at pH 6.0. The saturation complex ratio of SPI/κCG at pH 6.0 was 1:0.2 using isothermal titration calorimetry, and thermal complex with saturation ratio to form SCP as stabilizers could prepare emulsions with smaller droplet size in comparison of other ratios. Microstructure showed that SCP provided stabilization at the interface, and excess SCP formed network in the bulk phase to give solid-like emulsions. Furthermore, the power-law relationships of G′ with particle concentration (G' ∼ Cpn) and oil content (G' ∼ φm) was established. The exponent n and m decreased with increase of Cp and φ, indicating structure of SCPEs depends on Cp and φ. The G'/G″ crossover strain (γco) is indicator of breakdown of emulsion structure. For φ ≤ 20%, γco slightly decreased with increasing Cp; For 30%<φ<50%, γco increased with increasing Cp; For φ = 60%, γco significantly decreased with increasing Cp. In summary, these findings indicate the structure and rheology of soy protein-based emulsion can be regulated by controlling the formation condition of SCP and altering the SCP concentration and oil content.

Circular Polarization-Resolved Raman Optical Activity: A Perspective on Chiral Spectroscopies of Vibrational States.

Circular polarization-resolved Raman scattering methods include Raman optical activity (ROA) and its derivative─surface-enhanced Raman optical activity (SEROA). These spectroscopic modalities are rapidly developing due to their high information content, stand-off capabilities, and rapid development of Raman-active chiral nanostructures. These methods enable a direct readout of the vibrational energy levels of chiral molecules, crystals, and nanostructured materials, making it possible to study complex interactions and the dynamic interfaces between them. They were shown to be particularly valuable for nano- and biotechnological fields encompassing complex particles with nanoscale chirality that combine strong scattering and intense polarization rotation. This perspective dives into recent advancements in ROA and SEROA, their distinction from surface-enhanced Raman scattering, and the potential of these information-rich label-free spectroscopies for the detection of chiral biomolecules.

Novel insights into the molecular structure of lignite and its oxidation characteristics: A comprehensive characterization from single molecule of intermediates to complex coal

The structure of lignite is commonly believed to consist of fused aromatic rings (FARs) with 1 and 2 rings and short methylene chains, with few FARs with 3 or more rings and long aliphatic hydrocarbon (LAH) chains. This work presents a controlled stepwise alkali‑oxygen oxidation (AOO) of Xiaolongtan lignite to produce intermediates with characteristic structures. The humic acids and oxidative residues obtained were rich in aromatics and aliphatics, respectively. Based on complementary information of FARs with 3 or more rings and LAHs in the intermediates, a new structural model of lignite (C3661H3435O1036N81S7) from single molecules of intermediates to complex particles has been developed in conjunction with material characterization and computation. There are 43.7% one fused aromatic ring (1FAR), 39.3% 2FAR, 14.7% 3FAR, and 2.4% 4FAR, amount which there 15.9% pyrrole- and 2.4% pyridines- based aromatic rings. The controlled oxidation could prevent the ring-opening reaction of FARs and excessive oxidation of LAHs, thus leading to an in-depth understanding of the AOO process and lignite structure.

Combining in-situ observation and interfacial rheology as a tool to investigate the possible mechanism for improved emulsifying performance of gliadin-based colloid particles

Interfacial deformation and interfacial rheology behaviour of prolamin particles are relevant factors affecting their emulsification performance but have not yet been paid considerable attention to. Based on the finding that CMC modification significantly improved the emulsifying property of gliadin colloid particles (GCPs), the present study combined in situ observation and interfacial rheology as a tool to investigate the effect of CMC on the structure characteristics, interfacial deformation and interfacial rheology behaviour of GCPs and their correlation with emulsifying performance. The results demonstrated that gliadin/CMC complex particles (GCCPs) presented looser core-shell structures than GCPs. The interfacial deformation of particles and the formation of smooth interfaces were observed for both GCPs and GCCPs, and GCCPs exhibited faster deformation behaviour, which should correlate to the looser structure. Although GCCPs showed lower surface pressure and viscoelasticity modulus, the existence of CMC promoted the initial adsorption of particles and accelerated the formation of viscoelastic interfacial films, which contributed to the improvement of emulsifying performance. In addition, CMC endowed the interfacial layers with moderate viscosity and fluidity to resist the destabilisation induced by oil droplet deformation. The present study should provide insights for intuitive understanding and fine regulation of the interfacial behaviour of protein particles.

An improved DSMC method for acoustic agglomeration of solid particles assisted by spray droplets

The direct simulation Monte Carlo (DSMC) method was improved for describing the process of acoustic agglomeration assisted by spray droplets. The agglomeration and rebound as consequences of inter-particle collisions were modeled by considering all possible particle types, in particular, mixed-phase particles associated with the immersion and distribution mechanisms. Numerical predictions by the present method were validated by both analytical solutions and experimental data. The dynamic process of the acoustic agglomeration in terms of the size and type evolution as well as the evolution of number concentration of different particle types were examined. Results suggest that the strong interaction between the solid particles and the spray droplets causes the significant enhancement of acoustic agglomeration. Furthermore, the effect of frequency varying from audible to ultrasonic range on the acoustic agglomeration was evaluated. Overall, a better performance of acoustic agglomeration can be achieved at a lower frequency, regardless of addition of spray droplets. Agglomeration efficiency of 64.8 % can be achieve at acoustic frequency of 1000 Hz in case with spray droplets. This study provides not only a numerical model for describing the agglomeration of complex particles in particle-laden gas flows, but also important insights into the acoustic agglomeration assisted by spray droplets.

Designing a set of criteria for evaluating artificial neural networks trained with physics-based data to replicate molecular dynamics and other particle method trajectories

This article presents an in-depth analysis and evaluation of artificial neural networks (ANNs) when applied to replicate trajectories in molecular dynamics (MD) simulations or other particle methods. This study focuses on several architectures—feedforward neural networks (FNNs), convolutional neural networks (CNNs), recurrent neural networks (RNNs), time convolutions (TCs), self-attention (SA), graph neural networks (GNNs), neural ordinary differential equation (ODENets), and an example of physics-informed machine learning (PIML) model—assessing their effectiveness and limitations in understanding and replicating the underlying physics of particle systems. Through this analysis, this paper introduces a comprehensive set of criteria designed to evaluate the capability of ANNs in this context. These criteria include the minimization of losses, the permutability of particle indices, the ability to predict trajectories recursively, the conservation of particles, the model’s handling of boundary conditions, and its scalability. Each network type is systematically examined to determine its strengths and weaknesses in adhering to these criteria. While, predictably, none of the networks fully meets all criteria, this study extends beyond the simple conclusion that only by integrating physics-based models into ANNs is it possible to fully replicate complex particle trajectories. Instead, it probes and delineates the extent to which various neural networks can “understand” and interpret aspects of the underlying physics, with each criterion targeting a distinct aspect of this understanding.

Depletion of proteasome subunit PSMD1 induces cancer cell death via protein ubiquitination and DNA damage, irrespective of p53 status

Hepatocellular carcinoma (HCC) is characterized by high incidence and fatality rates worldwide. In our exploration of prognostic factors in HCC, the 26s proteasome subunit, non-ATPase 1 (PSMD1) protein emerged as a significant contributor, demonstrating its potential as a therapeutic target in this aggressive cancer. PSMD1 is a subunit of the 19S regulatory particle in the 26S proteasome complex; the 19S particle controls the deubiquitination of ubiquitinated proteins, which are then degraded by the proteolytic activity of the complex. Proteasome-targeting in cancer therapy has received significant attention because of its practical application as an established anticancer agent. We investigated whether PSMD1 plays a critical role in cancer owing to its prognostic significance. PSMD1 depletion induced cell cycle arrest in G2/M phase, DNA damage and apoptosis of cancer cells, irrespective of the p53 status. PSMD1 depletion-mediated cell death was accompanied by an increase in overall protein ubiquitination. These phenotypes occurred exclusively in cancer cells, with no effects observed in normal cells. These findings indicate that PSMD1 depletion-mediated ubiquitination of cellular proteins induces cell cycle arrest and eventual death in cancer cells, emphasizing PSMD1 as a potential therapeutic target in HCC.

Body temperature responsive capsules templated from Pickering emulsion for thermally triggered release of β-carotene

In recent years, functional foods with lipophilic nutraceutical ingredients are gaining more and more attention because of its potential healthy and commercial value, and developing of various bioderived food-grade particles for use in fabrication of Pickering emulsion has attracted great attentions. Herein, the bio-originated sodium caseinate-lysozyme (Cas-Lyz) complex particles were firstly designed to be used as a novel interfacial emulsifier for Pickering emulsions. Pickering emulsions of various food oils were all successfully stabilized by the Cas-Lyz particles without addition of any synthetic surfactants, while the fluorescence microscopy and SEM characterizations clearly evidenced Cas-Lyz particles were attached on the surface of emulsion droplets. Additionally, the Cas-Lyz particles stabilized emulsion can also be used to encapsulate the β-carotene-loaded soybean oil, suggestion a potential method to carry lipophilic bioactive ingredients in an aqueous formulation for food, cosmetic and medical industry. At last, we present a Pickering emulsion strategy that utilizes biocompatible, edible and body temperature-responsive lard oil as the core material in microcapsules, which can achieve hermetic sealing and physiological temperature-triggered release of model nutraceutical ingredient (β-carotene).

A novel particle decomposition scheme to improve parallel performance of fully resolved particulate flow simulations

This study addresses the challenge of simulating realistic particle systems by proposing a novel particle decomposition scheme that improves the parallel performance of surface resolved particle simulations. Realistic particle systems often involve large numbers of particles and complex particle shapes. The resulting need to account for shape factors requires the inclusion of even more particles to obtain statistically meaningful results. However, the computational cost increases with the number of particles, making efficient parallelization crucial. Therefore, the proposed scheme aims to improve the scalability by optimizing the communication and data management between processors. Through hindered settling experiments, the applicability and performance of the novel particle decomposition scheme are thoroughly investigated using the homogenized lattice Boltzmann method. The results show that the proposed method significantly improves the performance, especially in scenarios with a large number of particles, by reducing communication constraints and improving scalability. This research contributes to the advancement of computational methods for efficient study of complex particle systems and provides valuable insights for future developments in this field.

3D printed emulsion based on arginine-myofibrillar protein

The feasibility of preparing high internal phase Pickering emulsions (HIPPEs) from arginine (Arg) and tilapia myofibrillar protein (MP) complex particles for 3D printing was investigated. The characterization of Arg-MP solutions showed that the Arg-MP complexes had excellent emulsification potential. HIPPE stabilized by Arg-MP had a strong self-supporting and stable gel structure. Therefore, HIPPE stabilized by Arg-MP showed excellent stability. Furthermore, the viscoelasticity and thixotropic recovery of the Arg-MP-stabilized HIPPEs increased with increasing Arg concentrations. This made them suitable for 3D printing. Notably, the Arg-MP stabilized HIPPEs exhibited the best printing precision shape, resolution, and clear contours in 3D printing at an Arg concentration of 0.5 wt%. Our results provide a valuable source of food-grade materials for 3D printing inks and demonstrate a promising strategy for deep processing of tilapia myofibrillar protein.

Effect of solubilization with surfactant on the antioxidant activity of ellagic acid

Abstract Ellagic acid (EA) is a natural antioxidant found in many fruits and vegetables. However, its solubility in water is poor, which limits its application. To overcome this limitation, the surfactants Span 20 and Tween 60 are used to increase its solubility in water. FTIR, TEM and laser particle size and zeta potential analysis were used to characterize the morphology and structure of ellagic acid emulsions. The antioxidant activity of surfactant-compatible ellagic acid was determined using various antioxidant evaluation methods such as DPPH and ABTS radical scavenging, reducing power and total antioxidant activity. The results indicate that the solubility of ellagic acid in water was improved by the addition of Span 20 and Tween 60, and ellagic acid formed complex particles in combination with Span 20 and Tween 60. Compared to pure ellagic acid, the antioxidant activity of ellagic acid lotion was significantly enhanced.

Influence of carboxymethyl cellulose on the stability, rheology, and curcumin bioaccessibility of high internal phase Pickering emulsions

Recently, there has been a focus on using biopolymer-based particles to stabilize high internal phase Pickering emulsions (HIPPEs) due to the notable advances in biocompatibility and biodegradability. In this work, the complex particles of peanut protein isolate and carboxymethyl cellulose (CMC) with various substitution degrees (DS; 0.7 and 0.9) and weight average molecular weights (Mw; 90, 250, and 700 kDa) were prepared and characterized as novel stabilizers. For the obtained four types of morphologically distinct particles, the complex particles formed by CMC (0.9 DS and 250 kDa) showed cluster structures with an average size of 1.271 μm, equally biphasic wettability with three-phase contact angles of 91.5°, and the highest diffusion rate at the oil-water interface. HIPPEs stabilized by these particles exhibited more elastic behavior due to the smaller tanδ and higher viscosity, as well as excellent thixotropic recovery properties and stability against heating, storage, and freeze-thawing. Furthermore, confocal laser scanning microscopy verified that these particles formed a dense interfacial layer around the oil droplets, which could resist flocculation and coalescence between oil droplets during in vitro digestion. The improved bioaccessibility of curcumin-loaded HIPPEs made these delivery systems potentially apply in functional foods.

Exploring the Link between Hydrodynamic Size and Immunoglobulins of Circulating Immune Complexes in Rheumatoid Arthritis Patients.

The function of immune complexes in rheumatoid arthritis (RA) is related to their composition and size. Using dynamic light scattering (DLS), we investigated the link between the RA circulating immune complex (CIC) particles' size and the CIC immunoglobulin level. In this study, 30 RA patients and 30 healthy individuals were included. IgA, IgG, and IgM were found in all analyzed CICs, but more IgA and IgG were found in RA than in control CICs. In both control and RA CICs, DLS detected 50 particles that differed in size and clustered around two size groups: with a 7.5-164 nm radius and with a 342-1718 nm radius. An increased level of IgA in RA CICs, compared to control ones, was associated with more than 50% of CIC particles. In RA, compared to the control, a higher number of CICs with 28.2 nm, 531 nm, 712 nm, and 1718 nm particles and a lower number of CICs with 78.8 nm particles were detected. This particle distribution pattern did not reflect the changes in the CIC immunoglobulin level. Thus, RA elevated CIC IgA was linked with all these particles (except the 1718 nm particle), the IgM increase was linked with 43.8 nm and 712 nm particles, and the IgG increase was linked with the 712 nm particle only. This study provides the very first data on the association between CIC particles' size, CIC immunoglobulin level, and RA. It opens the possibility that the size of CICs determined by DLS can be used as a criterion in RA diagnosis or monitoring after a large-scale study confirmation.

Efficacy of a Maillard-type conjugate of whey protein isolate with chitosan as a carrier for a liposomal form of a combination of curcumin and balanced amounts of n-3 and n-6 PUFAs. Part I. structure – Functionality relationships

The Maillard-type WPI–chitosan conjugate was prepared through dry heating at 60 °C and 75% relative humidity for 72 h at a weight excess of WPI (8.7-fold) relative to CHIT (75% of deacetylation). The focus of the study was the soluble fraction (68% w/w) of the WPI–CHIT conjugate in the pI range of WPI (pH 4.5). SDS-PAGE analysis revealed that 16% of the total WPI was covalently bonded to CHIT. SDS-PAGE and SEC identified a 29% degree of binding for α-lactalbumin. DSC, fluorimetry, and FTIR detected unfolding of globular whey proteins in the conjugate. The conjugate encapsulated 94% of phosphatidylcholine liposomes loaded with fish oil and curcumin, resulting in complex particles. EPRS, DSC, fluorimetry, laser light scattering, tensiometry, and TEM provided insights into the structural and thermodynamic parameters underlying the functionality of the latter: water solubility, protective ability for encapsulated nutraceuticals, and lower foaming ability compared to that of the WPI–CHIT conjugate.

Efficacy of a Maillard-type conjugate of whey protein isolate with chitosan as a carrier for a liposomal form of a combination of curcumin and balanced amounts of n-3 and n-6 PUFAs. Part II. Carrier behaviour under simulated in vitro digestion

The study evaluated the benefits of using the whey protein isolate (WPI)–chitosan (CHIT) carrier formed via a Maillard reaction step to enhance the bioavailability of a liposomal form of nutraceuticals during in vitro gastrointestinal digestion according to the INFOGEST protocol. Liposomes appeared uniformly released from their hydrolysed complex [WPI–CHIT]–(PC–FO–CUR) during both the gastric (54 ± 9%) and small intestinal (46 ± 7%) stages in vitro. This was due to the initial encapsulation of liposomes (94%) by both WPI and chitosan in the soluble fraction of the Maillard-type conjugate. During the gastric stage, the mucoadhesiveness of the complex was improved by covalently attaching chitosan to thermally denatured WPI. The WPI denaturation was confirmed by DSC. Furthermore, both components aided in maintaining the complex's mucoadhesiveness during the small intestinal stage. Laser light scattering, TEM, EPRS, and tensiometry characterized interactions of hydrolysed complex particles and liposomes with mucin or bile salts in the GIT in vitro.

Experimental study of interactions between dual porous particles released side by side during settling

The settling of porous particles is relevant to many fields of research, which is essential for many natural phenomena and industrial processes. However, due to the complex particle–particle and particle–fluid interactions, the mechanism of porous particles settling has not been fully understood yet. In this study, the settling behaviors and interactions of dual porous particles released side by side are experimentally investigated. The Reynolds number varied from 12 to 258, which is within the transition zone. Particle Tracking Velocimetry and Particle Image Velocimetry were utilized to capture the particles' trajectories and velocities and provide insight into the flow fields around the particles, respectively. The influences of particle porosity ɛ, initial spacing between particles l0*, and Reynolds number Re on the settling process are systematically studied. In this study, ɛ varies from 0 to 0.858 and l0* varies from 0 to 5. The experimental results reveal that there was repulsion between porous particles during settling, which was negatively correlated with l0* and ɛ. When ɛ &amp;gt; 0.3 and l0* &amp;lt; 0.5, the magnitude of the repulsion between porous particles is significantly different from that of the solid particles, and thus, the effect of porosity is important. For other cases, the interaction between porous particles is essentially the same as that between solid particles. The repulsion between the two particles is a result of flow fields asymmetry, and this repulsion vanishes when l0* &amp;gt; 5. The settling process can be divided into three stages depending on the repulsion. Compared to solid particles, the interactions between porous particles are weaker. The reason is that the pore reduces the duration of particle interactions in the repulsion phase, which contributes to the particles to rapid approaching to reach the stable phase.

Experimental research on instrumentation for measuring automotive exhaust particle concentrations

Due to the absence of domestic automotive exhaust measurement methods, this paper, based on the principle of condensation nucleus growth counting, has developed a nanoparticle counter suitable for automotive exhaust detection. The paper incorporates the peak value counting method and conducts comparative experiments between different counting methods of the nanoparticle counter and the results obtained by electrostatic counting, as well as parallel experiments with a TSI CPC. The following results were obtained: (1) Compared to the traditional rising edge counting method, the peak value counting method significantly improves counting accuracy. (2) When the concentration is below 12, 500 P/cc, the peak value counting method can count more particle signals. (3) In the testing of complex particle clusters in automotive exhaust, the nanoparticle counter can be used for measuring automotive exhaust emissions.

Evolution of a long-duration transpolar arc during very quiet period

In this study, we explore the evolution of long-duration transpolar arcs observed during an exceptionally quiet period by the Fengyun-3D and Defense Meteorological Satellite Program satellites on 17 January 2019. Leveraging the extensive field of view of WAI, we captured the complete structure and evolution of the TPA over a very quiet period exceeding 7 h, with AE&amp;lt;30 nT. The TPA initially manifested at the poleward boundary of the auroral oval in the dawn sector, gradually migrating towards the dusk as the y-component of the interplanetary magnetic field (IMF BY) transitioned from negative to positive. Throughout this phase, the TPA underwent a distortion, transforming from a straight line to an “l-shape”. Following a reversal in interplanetary magnetic field BY to negative, the TPA retraced its path towards dawn and ultimately dissipated when the IMF turned southward. Of particular interest is the observation that when the TPA approached the noon-midnight line, small-scale spiral structures became apparent within the TPA. This suggests the presence of intricate small-scale magnetic field topologies or plasma instabilities/shears in the source region. These observations highlight the likelihood of complex field and particle dynamics in the high-latitude reconnection region and the twisted tail plasma sheet.

Shear Resistance Evolution of Geogrid-Aggregate Interfaces under Direct Shear: Insights from 3D DEM Simulations

This paper presents a mesoscopic evaluation of the shear resistance evolution of geogrid-aggregate interfaces subjected to direct shear loading. A three-dimensional discrete element method (DEM) model was developed based on experimental data. The tensile response of geogrid were simulated through a series of calibration tests. Aggregate with complex particle shapes were simulated to accurately capture the interlocking effect among aggregates based on the real particle surface. The individual shear resistance components were quantified based on particle displacement field and contact distribution characteristics. The influences of aperture-aggregate size ratio and geogrid stiffness on the shear resistance components are discussed. The results indicate that the peak value of shear resistance component follows a descending order from frictional resistance of aggregate, to passive resistance of transverse rib, and to geogrid-aggregate interface frictional resistance. During the shear process, the frictional resistance of aggregate becomes active first, followed by the geogrid-aggregate interface frictional resistance, and then the development of passive resistance of transverse ribs starts with a certain lag. Optimizing the geogrid-aggregate size ratio and utilizing geogrids with higher rib stiffness could enhance the passive resistance of transverse ribs but would not significantly affect the geogrid-aggregate interface frictional resistance and frictional resistance of aggregate.