Scattering Measurements Research Articles

The affinity towards the hydrophobic region of biomimicking bacterial membranes drives the antimicrobial activity of EFV12 peptide from Lactobacillus gasseri gut microbiota

The gut microbiota consists of a large variety of microorganisms, which interact with the immune system and exert essential roles for the human body health. Many of these microorganisms are also capable of producing various bioactive molecules, such as selective antimicrobial peptides, thus promoting the proliferation of only certain bacterial strains. These result in the shaping of the composition of the local microbiome and the co-evolution with a complex microbiome. Recently, a small peptide, named EFV12 and deriving from the bacterium Lactobacillus gasseri SF1109 regularly placed in the human intestine, showed a significant antimicrobial activity. Here we discuss a biophysical study on the structural changes induced by the peptide on lipid bilayers mimicking bacterial membranes with the aim of shedding light on the molecular features driving the biocidal activity against Gram(+) and Gram(−) strains. Supported Lipid Bilayers and liposomes composed of 1,2-oleoyl-sn-glycero-3-phosphocholine and 1,2-oleoyl-sn-glycero-3-rac-phosphoglycerol, both in the absence and presence of cardiolipin and lipopolysaccharides (LPSs), were selected to investigate the peptide-lipid interactions through a combination of specular Neutron Reflectometry, Dynamic Light Scattering, Small-Angle X-ray Scattering and Circular Dichroism measurements. The obtained results indicated association of EFV12 peptide with the hydrophobic region of lipid bilayers, which caused their destabilization, and is thus driving the antimicrobial activity against bacterial cells.

Light Scattering Measurements of KCl Particles as an Exoplanet Cloud Analog

Salt clouds are predicted to be common on warm exoplanets, but their optical properties are uncertain. The Exoplanet Cloud Ensemble Scattering System (ExCESS), a new apparatus to measure the scattering intensity and degree of linear polarization for an ensemble of particles, is introduced here and used to study the light scattering properties of KCl cloud analogs. ExCESS illuminates particles with a polarized laser beam (532 nm) and uses a photomultiplier tube detector to sweep the plane of illumination. Scattering measurements for KCl particles were collected for three size distributions representative of modeled clouds for the warm exoplanet GJ 1214b. Our measurements show that Lorenz–Mie calculations, commonly used to estimate the light scattering properties of assumedly spherical cloud particles, offer an inaccurate depiction of cubic and cuboid KCl particles. All of our measurements indicate that Lorenz–Mie scattering overestimates the backscattering intensity of our cloud analogs and incorrectly predicts the scattering at mid-phase angles (∼90°) and the preferential polarization state of KCl scattered light. Our results align with the general scattering properties of nonspherical particles and underscore the importance of further understanding the effects that such particles will have on radiative transfer models of exoplanet atmospheres and reflected light observations of exoplanets by the upcoming Nancy Grace Roman Space Telescope and Habitable Worlds Observatory.

Magnetic Properties of YbBe13 Probed by Neutron Scattering and Thermodynamic Measurements

Magnetic Properties of YbBe₁₃ Probed by Neutron Scattering and Thermodynamic Measurements

Nanofluidic Detection Platform for Simultaneous Light Absorption and Scattering Measurement of Individual Nanoparticles in Flow.

Characterization and quantification of plasmonic nanoparticles at the single particle level have become increasingly important with the advancements in nanotechnology and their application to various biological analyses including diagnostics, photothermal therapy, and immunoassays. While various nanoparticle detection methodologies have been developed and widely used, simultaneous measurement of light absorption and scattering from individual plasmonic nanoparticles in flow is still challenging. Herein, we describe a novel nanofluidic detection platform that enables simultaneous measurement of absorption and scattering signals from individual nanoparticles within a nanochannel. Our detection platform utilized optical diffraction phenomena by a single nanochannel as both a readout signal for photothermal detection and a reference light for interferometric scattering detection. Through the elucidation of the frequency effect on the detection performance and optimization of experimental conditions, we achieved the classification of gold and silver nanoparticles with a diameter of 20-60 nm at an average accuracy score of 82.6 ± 2.1% by measured data sets of absorption and scattering signals. Furthermore, we demonstrated the concentration determination of plasmonic nanoparticle mixtures using a trained Support vector machine (SVM) classifier. Our simple yet sensitive nanofluidic detection platform will be a valuable tool for the analysis of nanoparticles and their applications to chemical and biological assays.

Evidence of Sub‐Micrometric Plastic Release When Heating Food Containers Based on Light Scattering Measurements

Evidence of Sub‐Micrometric Plastic Release When Heating Food Containers Based on Light Scattering Measurements

Biofabrication of Silver Nanoparticles Using Green Seaweed: Characterisation and Antibacterial Evaluation

This study investigates the Chaetomorpha antennina (CA) seaweed-mediated biosynthesis of silver nanoparticles (AgNPs). The synthesis process of silver nanoparticles was monitored over time with the help of an Ultraviolet-visible spectrophotometer and further characterisation studies were also performed. Differential Light Scattering (DLS) measurements revealed a mean particle size of approximately 103.5nm and a mean zeta potential value of -57.5mV for AgNPs. The spherical shape and size of the AgNPs were confirmed through High-Resolution Transmission Electron Microscopy (HR-TEM) imaging, while Energy Dispersive X-ray Spectroscopy (EDAX) analysis provided insights into the elemental composition. The concentration of AgNPs was estimated using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The antibacterial potential of AgNPs was evaluated against both gram-positive (Bacillus cereus, Staphylococcus aureus and Bacillus subtilis) and gram-negative bacterial strains (Klebsiella pneumoniae, Escherichia coli, Shigella dysentriae, Salmonella typhi, Pseudomonas aeruginosa and Proteus mirabilis) using the agar well diffusion method. From the results, AgNPs exhibited significant antibacterial activity against B. subtilis and S. typhi among all the tested concentration levels (25, 50, 75 and 100μl).

Characterization of Surfactant Spheroidal Micelle Structure for Pharmaceutical Applications: A Novel Analytical Framework.

We introduce an innovative theoretical framework tailored for the analysis of Pair Distribution Function (PDF) data derived from Small-Angle X-ray Scattering (SAXS) measurements of core-shell micelles. The new approach involves the exploitation of the first derivative of the PDF and the derivation of analytical equations to solve the core-shell micelle structure under the hypothesis of a spheroidal shape. These analytical equations enable us to determine the micelle's aggregation number, degree of ellipticity, and contrast in electron density between the core-shell and shell-buffer regions after having determined the whole micelle size and its shell size from the analysis of the first derivative of the PDF. We have formulated an overdetermined system of analytical equations based on the unknowns that characterize the micelle structure. This allows us to establish a Figure of Merit, which is utilized to identify the most reliable solution within the system of equations.

Synergistic effects of β-NaFeO2 ferrite nanoparticles for photocatalytic degradation, antibacterial, and antioxidant applications.

Here, synthesis and thorough characterization of β-NaFeO2 nanoparticles utilizing a co-precipitation technique is presented. XRD analysis confirmed a hexagonal-phase structure of β-NaFeO2. SEM revealed well-dispersed spherical nanoparticles with an average diameter of 45 nm. The FTIR spectrum analysis revealed weak adsorption bands at 1054 cm-1 suggested metal-metal bond stretching (Fe-Na). UV-Visible spectroscopy indicates a 4.4 eV optical band gap. Colloidal stability of β-NaFeO2 was evidenced via Zeta potential (-28.5 mV) and Dynamic Light Scattering (DLS) measurements. BET analysis reveals a substantial 343.27 m2 g-1 surface area with mesoporous characteristics. Antioxidant analysis indicates efficacy comparable to standard antioxidants, while concentration-dependent antibacterial effects suggest enhanced efficacy against Gram-positive bacteria, particularly Streptococcus. The Photocatalytic activity of β-NaFeO2 showed significant pollutant degradation (>90% efficiency), with increased degradation rates at higher nanoparticle concentrations, indicating potential for environmental remediation applications.

Dual-Channel Imine-Amine Photoisomerization in a Benzoimidazole and Benzothiazole Coupled System: Photophysics and Applications.

A molecule, namely 2-(1H-benzo[d]imidazol-2-yl)-6-(benzo[d]thiazol-2-yl)-4-bromophenol (BIBTB), having a two-way proton transfer unit of thiazole and imidazole moieties was synthesized and characterized by NMR, electrospray ionization mass spectrometry (ESI-MS), and single-crystal diffraction studies. Steady state and time-resolved spectral studies of BIBTB support excited state intramolecular proton transfer (ESIPT), causing imine-amine tautomerization through a two-way 6-membered H-bonded ring, where the N atoms of benzothiazole and the benzoimidazole unit are involved as proton acceptor sites. Interestingly, in a nonpolar and moderately polar solvent, photoisomerization in BIBTB is found to be favored toward the thiazole ring, whereas in a highly polar solvent, it is favored toward the imidazole ring. A spectral comparison of BIBTB with judicially designed molecules 2-(benzo[d]thiazol-2-yl)-4-bromophenol (HBT) and 2-(1H-benzo[d]imidazol-2-yl)-4-bromophenol (BIB) supports these inferences. Theoretical calculation using the Density Functional Theory (DFT) at CAM-B3LYP/6-311+G(d,p) level supports the existence of two low-energy 6-membered hydrogen-bonded planar conformers in the ground state in the gas phase and in solvents of different dielectrics. The potential energy curves (PECs) calculated along the proton transfer (PT) coordinate are found to have a high energy barrier in the ground state and to be barrierless or have a low energy barrier in the excited state for both the forms. The calculated vertical excitation and the emission energy from the relaxed excited and PT states show good correlation with the experimental spectral data. Aggregation of BIBTB in water with red shifted emission was established from X-ray single-crystal structure analysis, solid state emission, and Dynamic Light Scattering (DLS) measurement. The molecule BIBTB also acts as a fluorescence probe for sensing the explosive picric acid in the subnano scale and can be used to determine the proportion of water in dimethyl sulfoxide (DMSO) solvent.

Performance of JT-60SA Thomson Scattering data analysis system

We have developed signal processing routines for the Thomson Scattering measurement, which is planned for use in the next campaign of the JT-60SA large-scale tokamak experiment.This paper provides the data analysis system and its performance evaluated in terms of computation time and error.The sequential routine of determining the scattered light intensity from a simulated signal, including noise data from a 1 Gs/s high-speed sampling digitizer, and determining the electron temperature and density was tested for the first time on an actual machine.The data analysis system ensures that electron temperature and density can be calculated with reasonable relative errors and within a realistic time frame for operations on JT-60SA.

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.

Scattering measurements of rocky seafloors using a split-beam echosounder

Scattering measurements were made off the coast of Pacific Grove, CA at 200 kHz, in an exposed fractured granite seafloor. Using inertial sensors and a split-beam transducer, data were processed to obtain a range of grazing angles corresponding to scattering strength, and signal processing techniques were used to extract the relevant portion of each ping. The ensonified angular width from a circular aperture is presented. Scattering strength measurements using different assumptions regarding the grazing angle were compared. The empirical Lommel–Seeliger model provided a good fit to measured data with a parameter of −18.4 dB.

In-situ qualification and physics-based process design for aerosol jet printing via spatially correlated light scattering measurements

Aerosol jet printing is a contactless, digital, and additive technique broadly used for manufacturing flexible, hybrid, and conformal electronics. However, both intra-batch and batch-to-batch variability have hindered widespread industry adoption and scaling to production volumes. Recently, light scattering measurements have emerged as a tool to measure aerosol volume fraction – a key parameter determining deposition rate – and have proven an effective feedback source for closed-loop control on timescales ranging from tens of minutes to hours. While this is a promising capability to mitigate long-term process drift, it lacks the temporal resolution to validate print quality for complex and precise electronic circuits. Here, real-time process monitoring with <1 s resolution is demonstrated for in-situ qualification of aerosol jet printing. To begin, the correlation between light scattering and aerosol deposition is validated at 500 ms time intervals, allowing deposition rate to be mapped to positional coordinates and providing a new data stream to drive quality control assessments. This allows optical scattering to be connected to electrical properties including line and sheet resistance, resulting in predictions nominally within 10% of measured values for sets of printed devices. Finally, the ability to spatially correlate print defects during fabrication is demonstrated as a foundation for a print repair framework, successfully repairing prints with randomly induced defects to achieve resistance within 5% of a control set.

Facile route for preparation of cuprous oxide/copper/cupric oxide nanoparticles by using simultaneous electrochemical and reduction reaction

Cuprous oxide/copper/cupric oxide nanoparticles were synthesized through a hybrid process involving anodic dissolution and a controlled redox reaction between NaOH and glucose in the solution. The study demonstrates the structural manipulation of the material by varying the reaction components within the solution. Morphology, structural analyses using SEM (Scanning Electron Microscope), EDX (Energy-dispersive X-ray spectroscopy), TEM (Transmission Electron Microscope), FTIR (Fourier Transform Infrared Spectroscopy), XRD (X-ray diffraction), and XPS (X-ray photoelectron spectroscopy) unveiled the tunability of the material's structure based on the reaction components. Nitrogen adsorption analysis employing the Brunauer-Emmett-Teller (BET) equation confirmed the material's porosity, while Dynamic Light Scattering (DLS) measurements provided insights into the materials' hydrodynamic size and zeta potential. The results demonstrated that by increasing the glucose/NaOH ratio during the reaction, the different structures and morphologies of the distinct products were obtained from the clustering of small nanoparticles to cubic shape and flower-like structure. Antibacterial activity tests conducted on various bacterial strains showed a correlation between the morphology and structure of the material and its antibacterial properties. The highest substantial antibacterial efficacy against all tested bacterial strains at a dosage of 100 μg/L was obtained for the samples with clustering morphology, whereas the remaining materials showed no discernible antibacterial effect against one of the studied bacteria. The results also demonstrated that the sample with a clustering structure exhibited superior antibacterial properties when dispersed in water containing dimethylsulfoxide.

3-mm Recognition Capability of Forward Stimulated Brillouin Scattering Measurement by Brillouin Selective Sideband Amplification

3-mm Recognition Capability of Forward Stimulated Brillouin Scattering Measurement by Brillouin Selective Sideband Amplification

Fractionation of iron and titanium isotopes by ilmenite and the isotopic compositions of lunar magma ocean cumulates

Basaltic volcanism on the Moon produced low- and high-Ti mare basalt suites that are also distinct with respect to their iron, titanium, and magnesium isotopic compositions. Here, the equilibrium fractionation of Fe and Ti isotopes between ilmenite and melt was experimentally investigated in order to evaluate the role of ilmenite in generating the isotopic compositional variability among the lunar mare basalts. Ilmenite crystallization experiments were conducted using two bulk compositions: an ilmenite-saturated basaltic andesite and an ilmenite-saturated Apollo 14 black glass, and the Fe and Ti isotopic compositions of the experimental ilmenites and glass (quenched melt) were analyzed using solution MC-ICPMS after hand-picking. Additionally, Nuclear Resonant Inelastic X-ray Scattering (NRIXS) measurements on synthetic ilmenite were conducted and compared to previous NRIXS measurements on synthetic lunar glasses in order to derive temperature-dependent equilibrium ilmenite-melt Fe isotopic fractionations. Experimentally determined ilmenite-melt fractionations were then incorporated into a lunar magma ocean crystallization model that tracks the major element and isotopic compositional evolution of lunar magma ocean cumulates and residual liquid. There is good agreement between the Fe equilibrium isotopic fractionation measured by NRIXS and the laboratory equilibration experiments, and we find that the isotopic fractionation is sensitive to ilmenite compositional differences (0 vs. 10% Fe3+). Further, the light Ti isotopic composition of ilmenite relative to the melt (Δ49Ti=ilmenite-melt−0.09±0.03‰ at 1100∘C) is consistent with the higher coordination of Ti in ilmenite relative to melts and results of previous studies. The modeled Ti isotopic compositions for lunar magma ocean cumulates display Ti isotopic variability sufficient to explain the low- and high-Ti mare basalt sources. However, the difference in Fe isotopic composition between the low- and high-Ti mare basalts cannot be attributed solely to ilmenite fractionation. Instead, Fe isotopic fractionation by additional products of lunar magma ocean crystallization, such as clinopyroxene, is required to generate the inferred Fe and Mg isotopic variability in the lunar mantle. Alternatively, the Fe and Mg isotopic compositions of the lunar mare basalts may indicate Fe-Mg interdiffusion has occurred in the Ti-rich component of the mare basalt source regions via reaction between ilmenite cumulates and the olivine- and pyroxene-rich lunar mantle.

The Role of Mesons in Light-by-Light Scattering at Low Transverse Momentum

Abstract. Light-by-Light scattering involves the interaction of two strong elec tromagnetic fields, resulting in the emission of two photons. In the next years, the ALICE 3 experiment is going to measure photons in the transverse mo mentum range pt = 1 - 50 MeV and 100 - 5000 MeV, which have not been investigated so far. Moving to a lower range of pt imposes a consideration of low-energy meson resonances which decay into two-photon channel. Further more, experimental possibilities to investigate the VDM-Regge mechanism are discussed. The role of the vertical background in light-by-light scattering mea surements is also shown.

Possibilities of Light-by-Light Scattering Measurement in FoCal Detector

Possibilities of Light-by-Light Scattering Measurement in FoCal Detector

Novel Forward Brillouin Scattering measurement technique based on high-Q fiber ring resonator

The conventional detection of Forward Brillouin Scattering (FBS) in optical fibers requires of interferometric techniques using lengths of tens of meters. In this paper, we demonstrate an alternative approach that provides efficient and high-resolution detection of FBS signals, while using just a 20 cm length section of bare fiber. It consists of a pump and probe scheme using a fiber ring resonator as the interrogation system of the mechanical vibration, which modulates the resonances. The result is an amplitude modulated optical trace which allows the detection of resonances R0,m and TR2,m.

Ordered mesoporous silicas for potential applications in solid vaccine formulations

In an effort to develop efficient vaccine formulations, the use of ordered mesoporous silica (SBA-15) as an antigen carrier has been investigated. SBA-15 has required properties such as high surface area and pore volume, including narrow pore size distribution to protect antigens inside its matrix. This study aimed to examine the impact of solvent removal methods, specifically freeze-drying and evaporation on the intrinsic properties of an immunogenic complex. The immunogenic complexes, synthesized and incorporated with BSA, were characterized by various physicochemical techniques. Small Angle X-ray Scattering measurements revealed the characteristic reflections associated to pure SBA-15, indicating the preservation of the silica mesostructured following BSA incorporation and the formation of BSA aggregates within the macropore region. Nitrogen Adsorption Isotherm measurements demonstrated a decrease in surface area and pore volume for all samples, indicating that the BSA was incorporated into the SBA-15 matrix. Fluorescence spectroscopy evidenced that the tryptophan residues in BSA inside SBA-15 or in solution displayed similar spectra, showing the preservation of the aromatic residues’ environment. The Circular Dichroism spectra of BSA in both conditions suggest the preservation of its native secondary structure after the encapsulation process. The immunogenic analysis with the detection of anti-BSA IgG did not give any significant difference between the non-dried, freeze-dried or evaporated groups. However, all groups containing BSA and SBA-15 showed results almost three times higher than the groups with pure BSA (control group). These facts indicate that none of the BSA incorporation methods interfered with the immunogenicity of the complex. In particular, the freeze-dried process is regularly used in the pharmaceutical industry, therefore its adequacy to produce immunogenic complexes was proved Furthermore, the results showed that SBA-15 increased the immunogenic activity of BSA.