Multiple Light Scattering Research Articles

S-scheme charge transfer pathway in a hierarchical BiOCl0.7I0.3-P/TiO2 heterojunction for bifunctional bacterial inactivation and antibiotic degradation

Photocatalytic technology holds significant importance and feasibility in bacterial inactivation and antibiotic degradation. This study successfully fabricated a hierarchical inorganic BiOCl0.7I0.3-P/TiO2 (BOCI-P/TH) S-scheme heterojunction by in-situ growth of BiOCl0.7I0.3-P (BOCI-P) nanosheets on TiO2 hollow spheres (TH), which was capable of suppressing charge carrier recombination and enhancing oxidative-reductive capability. The charge transfer mechanism of the hierarchical BOCI-P/TH composite was elucidated by radical-trapping electron paramagnetic resonance and X-ray photoelectron spectroscopy analysis, revealing the mechanism behind high activities of the BOCI-P/TH photocatalysts in antibacterial and degradation. It was found that the multiple light-scattering in hierarchical structure enhanced the light absorption, tight contacted interface decreased electron transfer distance, and S-scheme charge transfer inhibited charge recombination. As a result, electrons and holes with strong redox ability were generated, resulting the formation of abundant ·O2- and ·OH radicals, achieving efficient sterilization and antibiotic degradation. The BOCI-P/TH catalysts exhibited outstanding photocatalytic activity and photostability for deactivating Staphylococcus aureus (99.99%) and degrading Rhodamine B (99.98%), tetracycline hydrochloride (84.81%), and ofloxacin (99.95%). This research provided valuable insights into the multi-strategy design of photocatalysts and the application of dual-functional catalysts in various environments.

Effect of Hydrolyzed Polyacrylamide on the Emulsion Stability by Multiple Light Scattering and Molecular Dynamics Simulation

AbstractPolymer flooding, using hydrolyzed polyacrylamide (HPAM), is crucial in enhanced oil recovery technology. The effect of the HPAM and NaCl concentration on the stability of the simulated emulsions was assessed through multiple light scattering experiments. The results demonstrated that HPAM significantly enhanced the stability of both oil‐in‐water (O/W) and water‐in‐oil (W/O) emulsions. The HPAM concentration escalated from 200 mg L−1 to 1000 mg L−1, increasing from 1.24% to 1.31% at 60 minute in the average backscattering of W/O emulsions. The average transmittance of O/W emulsions exhibited a significant decline from 2.54% to 0.12%. The NaCl concentration had a small effect on the stability of the emulsions. Molecular dynamics simulations revealed that HPAM adsorbed at the oil water interface by the point‐like nature, with stronger interaction between its amide group and the oil molecule than its carboxyl group. The hydrogen bond number and the hydrogen bond lifetime of HPAM‐H2O and HPAM‐HPAM increase with increasing the number of HPAM molecules at the oil‐water interface, slowing diffusion coefficient of water molecules and increasing the interface thickness. Increasing salinity can weaken the HPAM‐water interaction, reducing the emulsification stability. This work provides insights into the emulsification characteristics and mechanisms of HPAM.

Coupling static multiple light scattering (SMLS) analysis with the Hansen approach for the rationalization of the dispersibility and colloidal stability of TiO2 particle dispersions

While the characterization of dispersibility and colloidal stability remains a key step in many formulation processes, these notions are still confused, and colloidal stability is often interpreted as a direct consequence of dispersibility. In this study, Static Multiple Light Scattering (SMLS) measurements and the predictive Hansen approach are combined to distinguish and characterize the dispersibility and the colloidal stability of TiO2 P25 particles dispersed in pure and mixture of solvents. To this aim, an experimental protocol is proposed using fast time resolved SMLS measurements at a fixed height to assess suspension dispersibility under mechanical stirring as well as space and time resolved SMLS measurements of the suspension stability at rest. Dispersibility is quantified through a Dispersibility Index (DI) depending on the mean diameter of particles and transmission or backscattering signals standard deviation measured with SMLS under mechanical stirring. Quantification of colloidal stability is obtained from a Relative Turbiscan Stability Index (RTSI) measured at rest. Scoring of solvents is performed using the DI and the RTSI to build Hansen dispersibility and stability spheres respectively. It is found that the dispersibility and the stability spheres are clearly separated arguing that a lower colloidal stability is not necessarily a consequence of a poor dispersibility. Beyond this clarification, this combined SMLS-Hansen approach is a major step toward the optimization of dispersibility and stability of formulations. It can be also intended to find better dispersion media, greener and cheaper solvents to optimize particles suspensions, to reduce the content of costly stabilizing additive or to satisfy product regulatory requirements evolution.

Photonic Flatband Resonances in Multiple Light Scattering

We introduce the concept of photonic flatband resonances and demonstrate it for an array of high-index dielectric particles. We employ the multiple Mie scattering theory and demonstrate that both short- and long-range interactions between the resonators are crucial for the emerging and their associated . By examining both near- and far-field characteristics, we uncover how the flatbands emerge due to a fine tuning of resonators’ radiation fields, and predict that hybridization of a flatband resonance with an electric hot spot can lead to giant values of the Purcell factor for the electric dipolar emitters. Published by the American Physical Society 2024

Exopolysaccharide from marine microalgae belonging to the Glossomastix genus: fragile gel behavior and suspension stability

ABSTRACT With the aim to find new polysaccharides of rheological interest with innovated properties, rhamnofucans produced as exopolysaccharides (EPS) in a photobioreactor (PBR) and an airlift bioreactor (ABR) by the marine microalgae Glossomastix sp. RCC3707 and RCC3688 were fully studied. Chemical characterizations have been conducted (UHPLC – MS HR). Analyses by size-exclusion chromatography (SEC) coupled online with a multiangle light scattering detector (MALS) and a differential refractive index detector showed the presence of large structures with molar masses higher than 106 g.mol−1. The rheological studies of these EPS solutions, conducted at different concentrations and salinities, have evidenced interesting and rare behavior characteristic of weak and fragile hydrogels i.e. gel behavior with very low elastic moduli (between 10−2 and 10 Pa) and yield stresses (between 10−2 and 2 Pa) according to the EPS source, concentration, and salinity. These results were confirmed by diffusing wave spectroscopy. Finally, as one of potential application, solutions of EPS from Glossomastix sp. have evidenced very good properties as anti-settling stabilizers, using microcrystalline cellulose particles as model, studied by multiple light scattering (MLS) with utilization in cosmetic or food industry. Compared to alginate solution with same viscosity for which sedimentation is observed over few hours, microalgae EPS leads to a stable suspension over few days.

The Role of Multiple Light Scattering in the Interpretation of Transmission Spectra of Magnetic Fluids With Magnetite Nanoparticles in the Visible and Near-IR Regions

The Role of Multiple Light Scattering in the Interpretation of Transmission Spectra of Magnetic Fluids With Magnetite Nanoparticles in the Visible and Near-IR Regions

Salmonella YqiC exerts its function through an oligomeric state.

Protein oligomerization occurs frequently both in vitro and in vivo, with specific functionalities associated with different oligomeric states. The YqiC protein from Salmonella Typhimurium forms a homotrimer through its C-terminal coiled-coil domain, and the protein is closely linked to the colonization and invasion of the bacteria to the host cells. To elucidate the importance of the oligomeric state of YqiC in vivo and its relation with bacterial infection, we mutated crucial residues in YqiC's coiled-coil region and confirmed the loss of trimer formation using chemical crosslinking and size exclusion chromatography coupled with multiple angle light scattering (SEC-MALS) techniques. The yqiC-knockout strain complemented with mutant YqiC showed significantly reduced colonization and invasion of Salmonella to host cells, demonstrating the critical role of YqiC oligomerization in bacterial pathogenesis. Furthermore, we conducted a protein-protein interaction study of YqiC using a pulled-down assay coupled with mass spectrometry analysis to investigate the protein's role in bacterial virulence. The results reveal that YqiC interacts with subunits of Complex II of the electron transport chain (SdhA and SdhB) and the β-subunit of F0 F1 -ATP synthase. These interactions suggest that YqiC may modulate the energy production of Salmonella and subsequently affect the assembly of crucial virulence factors, such as flagella. Overall, our findings provide new insights into the molecular mechanisms of YqiC's role in S. Typhimurium pathogenesis and suggest potential therapeutic targets for bacterial infections.

Fast Inspection of Quality of Indigo Naturalis by Multiple Light Scattering.

Quality control of Chinese herbal medicine is a crucial component of Chinese herbal medicine research and development. Faced with the challenges of modernization and internationalization of Chinese herbal medicine, it is urgent to establish thorough and effective procedures for quality identification of Chinese herbal medicine, and there is an urgent need for new analytical and testing techniques that are efficient, accurate, and environmentally friendly. Multiple light scattering is a cutting-edge and analytical method that can accurately and rapidly assess the quality of Chinese herbal medicine without altering the nature or state of the sample or using organic reagents. Indigo Naturalis is considered a good remedy for pediatric hyperthermia, psoriasis, leukemia, and ulcerative colitis. In this study, the process of addition of Indigo Naturalis powder in water was recorded precisely using a multiple light scattering instrument. The qualitative and quantitative measurements of the instrument can be used to accurately capture the overall trajectory and sinking behavior of Indigo Naturalis powder into water and to establish a rapid evaluation method for the quality of Indigo Naturalis with the transmission and backscattering spectrograms of the sample as qualitative indicators and stability index as a quantitative indicator. The analytical technique based on multiple light scattering provides a fast, accurate, green, and environmentally friendly method for the quality evaluation of Indigo Naturalis and supports the development and transformation of high-quality Indigo Naturalis.

Erratum: Using Multiple Light Scattering to Examine the Stability of Phyllanthus emblica L. Extracts Obtained with Different Extraction Methods.

An erratum was issued for:Using Multiple Light Scattering to Examine the Stability of Phyllanthus emblica L. Extracts Obtained with Different Extraction Methods. The Authors section was updated from: Haozhou Huang1 Mengqi Li2 Chuanhong Luo3 Sanhu Fan4 Taigang Mo4 Li Han3 Dingkun Zhang3 Junzhi Lin5 1Innovative Institute of Chinese Medicine and Pharmacy/Academy for Interdiscipline, Chengdu University of Traditional Chinese Medicine 2Sichuan Nursing Vocational College 3School of Pharmacy/School of Modern Chinese Medicine Industry, State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China 4Sanajon Pharmaceutical Group 5TCM Regulating Metabolic Diseases Key Laboratory of Sichuan Province, Hospital of Chengdu University of Traditional Chinese Medicine to Haozhou Huang1,2 Mengqi Li3 Chuanhong Luo4 Sanhu Fan5 Taigang Mo5 Li Han4 Dingkun Zhang4 Junzhi Lin6 1State Key Laboratory of Southwestern Chinese Medicine Resources, Innovative Institute of Chinese Medicine and Pharmacy/Academy for Interdiscipline, Chengdu University of Traditional Chinese Medicine 2Meishan Hospital of Chengdu University of Traditional Chinese Medicine 3Sichuan Nursing Vocational College 4State Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine 5Sanajon Pharmaceutical Group 6TCM Regulating Metabolic Diseases Key Laboratory of Sichuan Province, Hospital of Chengdu University of Traditional Chinese Medicine.

Improving the performance of biobased polyurethane dispersion by the incorporation of photo-crosslinkable coumarin

High biobased carbon content polyurethane dispersions (PUD) are a more sustainable alternative to conventional oil-derived waterborne dispersions in coatings. However, there are still many performance limitations from restricted availability of effective renewable monomers and oligomers. This work demonstrates the improvement of the properties of high biobased content PUD and derived coating by introducing a photo-reversibly crosslinkable coumarin as chain extender within the structure. The effect of partial substitution of 1,3-propanediol biobased by a di-hydroxy photo-reactive cyclic coumarin on the particle size and the stability was analyzed by dynamic light scattering (DLS) and multiple light scattering (MLS). The lateral and more rigid structure of coumarin involved a moderated increment in particle size without significant effect on the dispersion stability for at least 45 days. Associated improvement in hardness and toughness was also demonstrated by tensile test, pendulum hardness, pencil hardness and scratch resistance test. Furthermore, controlled UV irradiation of the polyurethane gave rise to a mechanical performance adjustment from reversible photo-crosslinking and scission of the coumarin molecules within the macromolecular structure. A 70% dimerization degree of the coumarin within the polyurethane film by UV light provided a partially reversible threefold higher tensile strength than that of the original biobased formulation as an effective tool to tune the response of biobased polyurethanes.Graphical

Using Multiple Light Scattering to Examine the Stability of Phyllanthus emblica L. Extracts Obtained with Different Extraction Methods.

The extraction intermediate of traditional Chinese medicine is the key intermediate in the preparation process, and its stability has an important impact on the effectiveness and quality of the final product. However, existing stability evaluation methods are often time-consuming and labor-intensive, requiring long-term observation and the operation of complex equipment (such as high-performance liquid chromatography), and it is difficult to obtain more physical information about the instability of the system. Therefore, there is an urgent need to establish a fast and accurate stability analysis technology for traditional Chinese medicine. Multiple light scattering is a cutting-edge analytical method that can accurately and rapidly evaluate the stability of traditional Chinese medicines in an environment-friendly manner without changing the nature or state of the sample or using organic reagents. In this work, using the precise scanning data of multiple light scattering, the present protocol rapidly acquired the variation curves for layer thickness, particle migration speed, and average particle size over time. This enabled the precise identification of the mechanism and crucial characteristics causing the system's instability in its early stages. Of note, the research period for the extraction process can be considerably shortened by the detailed quantification of the system stability, which also allows for a quick, accurate, and in-depth analysis of the effects of various extraction processes on the stability of Phyllanthus emblica L.

Promising potential of bio-sourced amphiphilic xanthan as an emulsifier in O/W dispersions

The emulsification properties of hydrophobically modified xanthan (HMX) obtained through green esterification using alkenyl succinic anhydrides (ASA) as grafting agents were investigated by preparing oil-in-water emulsions without adding any surfactant, in order to better understand the stability phenomenon at the oil-water interface. This study demonstrated that new-brand bio-sourced HMX owns emulsifying potential compared to pristine xanthane, known for its poor interfacial properties as a non-absorbing polymer. A complete approach for studying the stability of the dispersions was carried out at different levels: a) macroscopic level: visual identification of stability, b) microscopic level: coupled optical microscopy and droplet size distribution and c) deep microstructure stability monitoring over time by Static Multiple Light Scattering. First, a series of HMX differing in alkenyl chain length and grafting density added at 0.2% w/w in emulsions were compared. Increased grafting density or hydrophobic chain length provided a highly stable and homogeneous emulsion over 30 days. In the case of less stable emulsions, two solutions are proposed: 1) increasing HMX concentration thus improving emulsifying properties, 2) adding native xanthan as a thickening agent, which slows down the creaming destabilization mechanism. This original article shows that the new-brand bio-sourced amphiphilic xanthan obtained under green modification synthesis behave promising and effective emulsifying capacities to stabilize oil-in-water emulsions, which offers promising potential for industrial applications.

Shedding light on the formation and stability of mesostructures in ternary “Ouzo” mixtures

Hypothesis: Ternary systems made of water, a water-miscible solvent, and hydrophobic solutes spontaneously produce metastable particles by the “Ouzo effect” and thermodynamically stable “Surfactant-Free Micro Emulsions” (SFME). However, the use of different analyses has led to a variability in the criteria to determine the boundaries of the Ouzo domain. We hypothesized that this could be clarified by investigating the stability and the physical state of the particles.Experiments: We investigate four systems using both solid and liquid solutes and two different solvents, and achieved a careful investigation of their phase diagrams, using DLS, Nanoparticle Tracking Analysis, NMR, Multiple Light Scattering, electrophoretic mobility, and fluorescence analysis.Findings: Our results evidence that the transition from the monophasic to the Ouzo domains does not coincide with the cloudiness curve, and that compositions in the Ouzo domain can look fully transparent, in contrast to what is often considered. This transition is best determined by stability analysis. The cloudiness curve corresponds to the formation of particles with a large size dispersity. In the Ouzo domain, we observed an exchange of solute between the continuous phase and solute particles swollen with solvent. In addition, the particles are stabilized against coalescence by their high negative charge.

A Boundary Integral Equation Formalism for Modeling Multiple Scattering of Light from 3D Nanoparticles Incorporating Nonlocal Effects

AbstractA novel computational scheme that models the scattering of light at interfaces in a deep‐nanometric (deep‐nm) plasmonic system is presented. The nonclassical effects associated with the collective motion of free electrons in metals of the system are investigated by a nonlocal hydrodynamic (HD) model. Due to the HD model, three types of interfaces, that is, the dielectric–dielectric interface, the dielectric–metal interface, and the metal–metal interface, are distinguished. The scattering of light at these interfaces is described by Boundary Integral Equations (BIEs), which are constructed by using the surface equivalence principle, the concept of the Green' function and the interface conditions. The BIEs are numerically solved by the boundary element method (BEM) for 3D nanoparticles of arbitrary shapes. To validate, the computed results are first quantitatively contrasted with analytical solutions from the Mie theory for spherical core–shell structures, with good agreements being demonstrated in both the near field and the far field. Then, a qualitative study is performed for dimers consisting of spheres with various gap sizes for both the classical local response model and the nonlocal HD model. The observed trends agree well with the results reported in previous works.

Plasmonically Enhanced Colloidal Quantum Dot/Graphene Doped Polymer Random Lasers.

An improvement in random lasers based on a colloidal quantum dot (QD)/graphene-doped polymer was observed and attributed to multiple light-scattering and graphene surface plasmon resonance. The emission characteristics of quantum dots doped with graphene oxide and reduced graphene oxide were compared. The QD/reduced graphene oxide hybrid exhibited a lower laser emission threshold (~460 μJ/cm2). The emission modes and thresholds were strongly dependent on both the graphene doping concentration and the external temperature. Decreased plasmon coupling was the primary reason for lower QD/graphene laser emission with increasing temperature. The optimum reduced graphene oxide concentration was 0.2 wt.%. This work provides a practical approach to optimizing the threshold and stability of random laser devices, with potential applications in displays, sensors, and anti-counterfeiting labels.

Multiple Light Scattering Measurements for Online Monitoring of Milk Fermentation.

The present paper investigates the use of multiple light scattering for the monitoring of milk fermentation. The experiments were performed on milk fermented with different starter concentrations (0.05% to 4.5% (w/w) at temperatures from 36 to 44 °C and in the presence of antibiotics at concentrations up to 100 µg/kg. The fermentation was monitored continuously by using a multiple light scattering technique and simultaneously by a pH meter, a rheometer and a texture analyzer. The backscattering signal recorded by multiple light scattering measurements was correlated with the changes in pH, rheological parameters and firmness of the samples along the fermentation. A gelation time of 120 min was obtained when the highest concentration of starter (4.5%, w/w) and incubation temperature of 44 °C were used. These results were confirmed by the pH, rheological and texture monitoring. The analysis of backscattering spectra allowed the detection of the effect of antibiotic on the gel formation even at low concentrations (1.3 µg/kg). Overall, the results highlighted the advantages of using a multiple light scattering technique as quality control tool for online monitoring of milk fermentation.

Effect of temperature on the heat treatment to recover green solvent from emulsion liquid membranes used in the extraction of Cr(VI)

One of the main difficulties to achieve a good performance with the emulsion liquid membranes technique for metal extraction is the solvent phase recovery. In the present work, heating is proposed as an efficient and easy method to destabilize extraction liquid membranes (ELM) used to recover Cr(VI) from wastewaters. The formulated ELM consists of sunflower oil as vegetable green solvent, PGPR and Tween 80 as surfactants, tri-n-octylphosphine oxide (TOPO) as an extractant and a sodium carbonate Na2CO3 (0.5 M) solution as the internal water phase.The effect of the temperature during demulsification process was investigated. The membrane phase was successfully demulsified by heating at 80 °C during 2 h, with a water content less than 4%. Emulsion were reformulated with recovered oil up to four times to extract Cr(VI) with an extraction efficiency (EE) up to 99 %. Physical properties of water-in-oil (W1/O) and ELMs formulated, using fresh and recovered oil, were characterized by dynamic light scattering (DLS) and multiple light scattering (MLS). Emulsions reformulated with recovered sunflower demonstrated to have not oil degradation, evaluated by dynamic scanning calorimetry (DSC) and Fourier transform infrared (FTIR), and were appropriate to form stable W1/O with high Cr(VI) removal capacity.

Fatty Acids Methyl Esters (FAME) autoxidation: New insights on insoluble deposit formation process in biofuels

The thermal and oxidation stability of fatty acids methyl esters (FAME) is arousing attention in the transport industry, since they are the main components present in biodiesel products used in the market. Low FAME stability can induce easy fuel degradation and produce oxidation products that can form sticky deposit causing serious malfunctioning and failures of engine and turbines components. We have focused the present work on the study of fuel oxidation process and the characterization of oxidation products in order to identify the main levers to avoid deposit formation. Soy and Rapeseed biodiesels were oxidized using an autoclave Parr reactor and characterized by FTIR, density and viscosity measurements. After oxidation, two different liquid phases were clearly observed. These two phases tend to form complex oil-oil emulsions after remixing as evidenced by optical microscopy. The separation behavior of the different liquid phases remixed after oxidation were studied using Multiple Light Scattering (TurbiscanTM). A comparison was made between the chemical functions of deposit obtained in the liquid phase after demixing (sedimented phase) and the solid deposit obtained on hot metallic surfaces. Results showed a that a complex oil-oil dispersion seems to form during the oxidation process. The phase separation rate of the oil-oil emulsified systems formed from oxidized fuels seems strongly related to the differences of polarity (e.g. oxygenates content) of both sedimented and supernatant phases. The understanding of this sedimentation or “demixing” process leading to deposit can be a key feature to develop strategies to prevent deposit formation in real systems.

Quantitative insight into dispersity and antibactericidal capability of silver nanoparticles noncovalently conjugated by polysaccharide-protein complexes

Precise prediction and measurement of dispersibility of silver nanoparticles (AgNPs) under atmospheric conditions are extremely vital for their potential commercial application. In the present work, the dispersibility of AgNPs capped by polysaccharide-protein from viscera of abalone (PSP-AgNPs) was studied using the combination of ultraviolet–visible spectroscopy (UV–vis), dynamic light scattering (DLS) and multiple-light-scattering (MLS) techniques. The results showed that the combination of UV/vis, DLS and MLS not only accurately determined the dispersibility of PSP-AgNPs, but also provided detailed information about the aggregation behavior of PSP-AgNPs. Furthermore, the results revealed a high dispersibility of PSP-AgNPs in the studied environment. The system temperature, pH value and thermal treatment (pasteurization and sterilization) had no effect on the dispersion of PSP-AgNPs in the effective concentration range against the pathogenic bacteria. Besides, an excellent stable dispersion and antibacterial activity against common pathogenic vibrio was also found in the dispersed PSP-AgNPs in seawater. Overall, the study provides a suitable method for the precise measurement of the dispersibility of AgNPs in environment. The AgNPs act as a potential bactericide with good dispersion and antibacterial activity in mariculture and other fields.

The influence of emulsion parameters on physical stability and rheological properties of Pickering emulsions stabilized by hordein nanoparticles

In this study, the effect of pH (3–8), ionic strength (I, 0.01–1 M), protein particle concentration (C, 0.5%–2%), and dispersed phase volume fraction (Φ, 0.25–0.8) on the efficacy of hordein-based colloidal nanoparticles in the stabilization of Pickering structures was investigated. Colloidal particles were synthesized via anti-solvent method. Depending on pH and I, the average size and zeta-potential of hordein particles ranged from 425 to around 4000 nm, and +27.5 to −15.63 mV, respectively. The intense aggregation of particles at pH close to isoelectric point and also at high I led to poor formation and stability of Pickering emulsions. The overrun value was influenced by various emulsion parameters. At pH 3, triphasic (with the overrun value of 75%) and high internal phase (HIP) emulsions with an average droplet size of 15.6–86.7 μm were formed at Φ 0.25 and 0.8, respectively. At Φ 0.5 and 0.8, an elastic gel-like behavior (i.e., storage modulus (G′) > loss modulus (G″)) was observed over the applied frequency range. At Φ 0.25, a predominant viscous character (G">G′) was observed at low frequencies; while, at higher frequencies, G′ exceeded G″ due to the foam collapse. The morphology was studied by optical microscopy and confocal laser scanning microscopy (CLSM). Monitoring the physical stability using static multiple light scattering (MLS) revealed three destabilization profiles of foam-like, emulsion-foam and gel-like structures. The results of this study might help in designing triphasic Pickering systems (using plant-based proteins) and developing solid-like structured vegetable oils from the gel-like HIP emulsions.