Multiple Light Scattering Research Articles

Optical Reservoir Computing Using Multiple Light Scattering for Chaotic Systems Prediction

Reservoir Computing is a relatively recent computational framework based on a large Recurrent Neural Network with fixed weights. Many physical implementations of Reservoir Computing have been proposed to improve speed and energy efficiency. In this study, we report new advances in Optical Reservoir Computing using multiple light scattering to accelerate the recursive computation of the reservoir states. Two different spatial light modulation technologies, namely, phase or binary amplitude modulations, are compared. Phase modulation is a promising direction already employed in other photonic implementations of Reservoir Computing. Additionally, we report a Digital-Micromirror-based Reservoir Computing at up to 640 Hz, more than double the previously reported frequency using a remotely controlled optical device developed by LightOn, and present new binarization strategies to improve the performance of binarized Reservoir Computing.

Disordered Optics: Exploiting Multiple Light Scattering and Wavefront Shaping for Nonconventional Optical Elements.

Advances in diverse areas such as inspection, imaging, manufacturing, telecommunications, and information processing have been stimulated by novel optical devices. Conventional material ingredients for these devices are typically made of homogeneous refractive or diffractive materials and require sophisticated design and fabrication, which results in practical limitations related to their form and functional figures of merit. To overcome such limitations, recent developments in the application of disordered materials as novel optical elements have indicated great potential in enabling functionalities that go beyond their conventional counterparts, while the materials exhibit potential advantages with respect to reduced form factors. Combined with wavefront shaping, disordered materials enable dynamic transitions between multiple functionalities in a single active optical device. Recent progress in this field is summarized to gain insight into the physical principles behind disordered optics with regard to their advantages in various applications as well as their limitations compared to conventional optics.

Preparation and characterization of emulgels loaded with sweet fennel oil

Stable emulgels formulated with sweet fennel oil, an essential oil with antioxidant and antibacterial activity, and a fumed silica (Aerosil 200) were prepared. A nylon membrane was the emulsification system chosen, which lead to high droplet sizes and poor stability. However, the addition of Aerosil 200 provoked the formation of stable emulgels. Rheology, Multiple Light Scattering technique and Scanning Electron Microscopy provided relevant information about the occurrence of a 3D network. Also, these techniques revealed the function of this fumed silica to increase the viscoelastic functions and to improve the physical stability of the emulgels developed. However, the results obtained indicated that the excess of Aerosil 200 is counterproductive for the physical stability inducing flocculation/coalescence.

Biofluidic Random Laser Cytometer for Biophysical Phenotyping of Cell Suspensions

Phenotypic profiling of single floating cells in liquid biopsies is the key to the era of precision medicine. A random laser in biofluids is a promising tool for the label-free characterization of the biophysical properties as a result of the high brightness and sharp peaks of the lasing spectra, yet previous reports were limited to the random laser in solid tissues with dense scattering. In this report, a random laser cytometer is demonstrated in an optofluidic device filled with gain medium and human breast normal/cancerous cells. The multiple lightscattering event induced by the microscale human cells promotes random lasing and influences the lasing properties in term of laser modes, spectral wavelengths, and lasing thresholds. A sensing strategy based on analyzing the lasing properties is developedto determine both the whole cell and the subcellular biophysical properties,and the malignant alterations of the cell suspensions are successfully detected. Our results provide a new approach to designing a label-free biophysical cytometer based on optofluidic random laser devices, which is advantageous for further research in the field of random laser bioapplication.

Synergistic Collaboration between Regenerated Cellulose and Surfactant to Stabilize Oil/Water (O/W) Emulsions for Enhancing Oil Recovery

A stable emulsion can play an important role in displacing oil or controlling reservoir conformance for enhanced oil recovery (EOR) projects. In this work, visual inspection, multiple-light scatter...

Biocellulose Masks as Delivery Systems: A Novel Methodological Approach to Assure Quality and Safety

Bacterial cellulose (BC) has become of great interest in recent years, as a delivery system in several areas of application, including food, drugs, and cosmetics, thanks to its exclusive advantages, such as high biocompatibility, water holding capacity, and good gas permeability. The novel approach of the authors has led to a protocol for checking the quality and safety of bacterial cellulose matrices in the manufacture of cosmetic masks. Two non-destructive techniques, near-infrared spectroscopy (NIR) and multiple light scattering (MLS), were used to verify different parameters affecting the quality of BC sheets, allowing cellulose masks to be checked over time. NIR spectroscopy allowed for discovering changes in the water content, depending on filling/packaging procedures, like flat-folding. Multiple light scattering was used to ascertain the stability of solutions in contact with masks. From a clinical standpoint, the cutaneous tolerability of biocellulose masks, and their effect on skin parameters, were evaluated through some specific “in vivo” tests. Also, a safety evaluation during application was conducted through different studies: a short-term one after single application, and a long-term one upon continued use.

Influence of a shear post-treatment on rheological properties, microstructure and physical stability of emulgels formed by rosemary essential oil and a fumed silica

Nanoemulsions containing rosemary essential oil, a natural food preservative, were developed by the microfluidization technique and emulgels were formed by adding a fumed silica (Aerosil 200). The influence of homogenization pressure on droplet size was examined. The nanoemulsion prepared at 5000 psi in Microfluidizer showed the lowest Sauter diameter and it was selected as the starting point. The influence of shear on rheological properties, stability and microstructure was studied for both the nanoemulsion and the emulgel formed. The emulsion showed recoalescence induced by shear, while the emulgel exhibited an alignment of a 3D-network. In addition, the prepared emulgel exhibited time-dependent behaviour. In spite of the fact that the viscoelastic functions of the emulgel decreased as a result of shear, a significant improvement in physical stability was detected by means of the Multiple Light Scattering technique.

Pickering emulsifiers based on hydrophobically modified small granular starches Part II – Effects of modification on emulsifying capacity

Small granular starches from rice, quinoa, and amaranth were modified with octenyl succinic anhydride (OSA) at 5 defined intervals (0–3.0%) and investigated with respect to emulsifying capacity and stability. Starch granule surfaces were characterized by Brunauer–Emmett–Teller and contact angle measurements. Emulsifying capacity was characterized by multiple light scattering (MLS) and particle size analysis. Stability towards environmental stress was characterized by centrifugation and MLS.Surface hydrophobicity and emulsifying capacity correlated with starch type and modification level. Quinoa stabilized emulsions had the smallest droplet size (e.g. 59.2 μm at 3.0% OSA) and superior stability, both before and after centrifugation, especially at the lowest modification levels. Rice and amaranth had larger droplets (99.8 and 84.1 μm at 3.0% OSA respectively). Amaranth, despite its small size showed poorer performance than quinoa, especially at lower modification levels. The higher emulsifying efficiency of quinoa starch granules attributed to the higher protein content.

Influence of Electric and Magnetic Fields on Interference Effects upon Multiple Light Scattering in Cold Atomic Ensembles

The correlation functions of the electromagnetic radiation scattered by an ensemble of atoms cooled to sub-Doppler temperatures and placed in an external static electric or magnetic field have been calculated by the diagram technique. Based on the derived relations, we have studied in detail the effect of coherent backscattering (CBS) of light. We have calculated the enhancement factor for CBS and analyzed its polarization and spectral dependences. We show that external fields affect the nature of multiple light scattering in an atomic ensemble, in particular, the character of interference upon such scattering, by leading to its optical anisotropy and related birefringence and dichroism. This, in turn, affects all of the observed CBS characteristics.

Development and characterisation of a continuous phase based on a fumed silica and a green surfactant with emulsion applications

Different ecological continuous phases were developed as a function of a green surfactant (Amidet N) and a fumed silica (Aerosil 200) concentration. The suitability of these systems was analysed by means of Small Amplitude Oscillatory Shear tests, flow curves, Cryo-SEM (Scanning Electron Microscopy) and the Multiple Light Scattering technique.An important rheological change in viscoelastic and flow properties was detected from 8 wt% to 9 wt% for binary systems of Aerosil/water. This rheological change was related to the interaction of Aerosil chains, which was reflected through the Cryo-SEM. As a consequence of the microstructure and, therefore, rheological properties, an increase in the physical stability of the more concentrated systems was observed. The addition of Amidet N provoked an increase in viscoelastic properties related to the effective interaction between Aerosil chains. Finally, a stable lemongrass essential oil-in-water was developed. In this study, the role of Aerosil 200 as rheological modified and stabilizer has been studied. On top of that, the synergic rheological effect between this fumed silica and Amidet N has been proved.

Assessing differences between Ostwald ripening and coalescence by rheology, laser diffraction and multiple light scattering

This contribution deals with the study of the influence of surfactant ratio, namely triblock copolymer (Pluronic PE9400) to polyoxyethylene glycerol fatty acid ester (Levenol C201), on the stability of emulsions formulated with a mixture of two biosolvents (N,N Dimethyl Decanamide and D-limonene), which find applications as carriers of agrochemicals. Emulsions containing Pluronic, regardless of the concentration studied, underwent Ostwald ripening while coalescence controlled the destabilization process of emulsions containing Levenol C201 as the only emulsifier. The physical stability of the emulsions was analysed not only by means of mean diameters determined by laser diffraction but also with respect to their rheological properties and the so-called TSI parameter derived from multiple light scattering measurements with aging time. We propose that the different structures of both surfactants at the oil/water interface may be responsible for the occurrence of different destabilization mechanisms. It is likely that Copolymer Pluronic PE9400 formed multilayers in the emulsions studied, which may promote flocculation during processing and, subsequently, Ostwald ripening. In contrast, Levenol C201 probably formed a compact adsorbed layer with the molecules perpendicularly oriented to the interface. This work illustrates to what extent the combination of information provided by Multiple Light Scattering, rheology and laser diffraction enables the detection and monitoring of destabilization mechanisms such as Ostwald ripening and coalescence. In addition, this research highlights the importance of surfactant selection for the physical stability of emulsions that exhibited similar droplet size distributions just after preparation.

Multiple Light Scattering 분석법을 이용한 천연수경성석회의 초기경화 거동

본 연구에서는 무기질 첨가재를 혼합한 천연수경성석회의 초기경화 거동분석을 위해 multiple light scattering 분석법을 이용하였다. 자체 제조한 천연수경성석회의 물성향상을 위해 고로수쇄슬래그 및 3종류의 석고를 혼합비에 따라 혼합하였으며 물-고체비 0.6으로 페이스트를 제조하였다. 제조한 페이스트를 이용하여 원통형의 용기에 일정량을 담아 장비(Turbiscan LAB, Formulaction)에 장입하여 분석을 실시하였다. 페이스트로부터의 backscattering flux(BS, %)는 <TEX>$23^{\circ}C$</TEX>의 온도에서 분석용기 전체높이(55 mm)에 대해 24시간 동안 10분 간격으로 측정되었다. 모든 시료에서 전체적으로 BS는 시간경과에 따라서 증가하는 경향성을 보였다. 고로수쇄슬래그와 석고를 첨가함에 따라서 시간에 따른 BS의 증가 속도는 0.02에서 0.38 BS %/hour 까지 증가하였다. 반수석고를 혼합하였을 경우 가장 높은 backscattering flux와 BS의 증가속도를 보였다. In the present study, the multiple light scattering method was used for analysis of early hardening behavior of natural hydraulic lime (NHL) containing inorganic additives. In order to improve the properties of self-manufactured NHL, blast furnace slag and three types of gypsum were mixed with mixing ratio, and a water/solid ratio of fresh NHL paste was fixed 0.6. The fresh pastes in flat-bottomed cylindrical glass tubes were placed in the instrument. The backscattering flux (BS) of light from fresh pastes was then periodically measured at 10 minutes intervals the entire length of the sample (55mm) at <TEX>$23^{\circ}C$</TEX> for 24 hours. The rate of increase of BS, slope of a linear equation to the mean value of BS (%) as a function of hydration time, was increased from 0.02 to 0.38 BS %/hour due to addition of blast furnace slag and gypsum. In the case of addition of hemi-hydrate, BS (%) and rate of increase in BS were highest.

Lyotropic liquid crystal based on zinc oxide nanoparticles obtained by microwave solvothermal synthesis

The ZnO nanoparticles, obtained by microwave solvothermal synthesis, were used for the liquid crystal phase preparation. The structure of the material was investigated by X-ray diffraction (XRD), helium pycnometry, specific surface area (SSA), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM). The stability of aqueous suspensions was monitored by Multiple Light Scattering (MLS) technique and the average agglomerate size in suspensions was obtained by dynamic light scattering (DLS) technique. The lyotropic columnar hexagonal phase was formed by doping ZnO nanoparticles into the cetylpiridinium chloride/water/hexanol system. The structure of this phase was confirmed by x-ray diffraction. The luminescent properties of the LC phase were compared with properties of ZnO nanoparticles isolated in solution and analogues lyotropic system without nanoparticles.

Antifungal organoselenium compound loaded nanoemulsions stabilized by bifunctional cationic surfactants

Over last few decades, organoselenium compounds have been extensively studied in organic and medicinal chemistry. Ebselen (2-phenylbenzisoselenazol-3(2H)-one, BSe) and its analogues have emerged as potential pharmaceuticals and promising catalysts of various oxidation reactions and potential pharmaceuticals. For instance, their biological interest relies on their antioxidant, anti-inflammatory and glutathione peroxidase-like activities as well as antimicrobial, antiviral and chemopreventive effects. One of the major obstacles for their practical use is poor water solubility. For this purpose the potential of dicephalic cationic surfactants, N,N-bis[3,3′-(trimethylammonio)propyl]alkylamide dichlorides, to form physically stable nanoemulsion-based drug carriers in the presence of a variety of oils (oleic acid, Capmul MCM and PG-8) and the organoselenium-derived cargo was explored. Nanoemulsions were characterized by visual and microscopic observations, as well as dynamic light scattering (DLS) measurements of particle size and distributions. Results of transmission electron microscopy (TEM) and DLS showed that nearly spherical droplets of very similar size were obtained, with oleic acid bringing best properties. Time-depended size (DH) and ξ-potential measurements, dispersion stability test and kinetic stability studies with multiple light scattering (MLS) technique proved high colloid stability of the fabricated systems. Positively charged nanoemulsions with high ξ-potential values up to 87mV showed no significant evolution in backscattering profiles. The nanoemulsions were evaluated for antimicrobial efficacy towards Candida albicans and its biofilm. Strong antifungal activity was observed, with deleterious morphological changes in cellular structures and yeasts cell surface alterations. In conclusion, the designed oil-in-water nanoemulsion-based carriers, stabilized by dicephalic cationic surfactants can comprise a promising delivery system for poorly water soluble organoselenium derivatives of efficient antimicrobial activities.

Complementary analysis techniques applied on optimizing suspensions of yttria stabilized zirconia

Three different polymers with different functional groups and similar molecular weight were tested as dispersing agents for suspensions of yttria stabilized zirconia in ethanol: polyvinyl pyrrolidone, polyethylene imine, polyvinyl butyral/acetal. The stability of the system was assessed considering, in details, all the processing steps, including suspension de-agglomeration, slurry manipulation, quality of sintered tapes microstructure, and final layer leak tightness. Different analytical techniques were used to monitor ceramic de-agglomeration and stability as a function of time, for different types of dispersing agent and to optimize the dispersants concentration: Electrokinetic Sonic Amplitude was used to obtain zeta potential, Multiple Light Scattering for evaluating sedimentation rate, and multi-wavelength laser light scattering for measuring particle size distribution. All the results agree upon excellent performance of polyvinyl pyrrolidone and polyethylene imine as dispersing agents. The stability and dispersing power were finally utilized for preparing concentrated suspensions for tape casting and subsequently to sinter the tapes into dense ceramic pieces.

Application of particle sedimentation analysis in sterically-stabilized TiO2 particles stability assessment

Particle sedimentation analysis is an important characterization technique for making reliable stability assessment of particles in suspensions. In this work, new analytical model was derived similar to Kynch’s continuity equation where negligible compression effect and constant solid volume concentration ϕs are assumed at the compression phase. However, this new model differs as it includes new expressions for forces due to inertia and accelerated fluid eddies. The new model was also employed in analysing dynamics of particles during sedimentation thereby making it useful to assess particle stability in suspensions as well as predict particle sedimentation profiles if variation of ϕs with time can be accurately measured.Stability of monodisperse spherically shaped TiO2 particles synthesized by the well-accepted sol–gel process and sterically stabilized separately by two different commercial surfactants, Brij30 and Brij76, were assessed via an instrument called Turbiscan and it operates based on principle of multiple light scattering (MLS) technique. The instrument measures variations in particle size and position as function of time and records as backscattered (BS) or transmitted (T) light intensity which can then be converted to ϕs expressed in terms of attenuation time and height. This makes the instrument applicable in validating the newly derived analytical model.

Skeletal light-scattering accelerates bleaching response in reef-building corals.

BackgroundAt the forefront of ecosystems adversely affected by climate change, coral reefs are sensitive to anomalously high temperatures which disassociate (bleaching) photosynthetic symbionts (Symbiodinium) from coral hosts and cause increasingly frequent and severe mass mortality events. Susceptibility to bleaching and mortality is variable among corals, and is determined by unknown proportions of environmental history and the synergy of Symbiodinium- and coral-specific properties. Symbiodinium live within host tissues overlaying the coral skeleton, which increases light availability through multiple light-scattering, forming one of the most efficient biological collectors of solar radiation. Light-transport in the upper ~200 μm layer of corals skeletons (measured as ‘microscopic’ reduced-scattering coefficient, mu ^{prime}_{{S,m}} ), has been identified as a determinant of excess light increase during bleaching and is therefore a potential determinant of the differential rate and severity of bleaching response among coral species.ResultsHere we experimentally demonstrate (in ten coral species) that, under thermal stress alone or combined thermal and light stress, low- mu ^{prime}_{{S,m}} corals bleach at higher rate and severity than high- mu ^{prime}_{{S,m}} corals and the Symbiodinium associated with low- mu ^{prime}_{{S,m}} corals experience twice the decrease in photochemical efficiency. We further modelled the light absorbed by Symbiodinium due to skeletal-scattering and show that the estimated skeleton-dependent light absorbed by Symbiodinium (per unit of photosynthetic pigment) and the temporal rate of increase in absorbed light during bleaching are several fold higher in low- mu ^{prime}_{{S,m}} corals.ConclusionsWhile symbionts associated with low- mu ^{prime}_{{S,m}} corals receive less total light from the skeleton, they experience a higher rate of light increase once bleaching is initiated and absorbing bodies are lost; further precipitating the bleaching response. Because microscopic skeletal light-scattering is a robust predictor of light-dependent bleaching among the corals assessed here, this work establishes mu ^{prime}_{{S,m}} as one of the key determinants of differential bleaching response.Electronic supplementary materialThe online version of this article (doi:10.1186/s12898-016-0061-4) contains supplementary material, which is available to authorized users.

Influence of Processing on the Physical Stability of Multiple Emulsions Containing a Green Solvent

AbstractThe influence of the emulsification process on the microstructure and physical stability of model water‐in‐oil‐in‐water (W/O/W) emulsions formulated with a green solvent and a mixture of amphiphilic copolymers as emulsifiers was investigated. Emulsions were prepared by applying a homogenization step with a rotor‐stator device followed by high‐pressure homogenization. Viscous flow tests, transmitted light optical microscopy, globule size distribution (GSD), and multiple light scattering (MLS) measurements were carried out. The GSDs obtained were the result of a recoalescence due to overprocessing and the coalescence of inner droplets with the outer water phase. MLS detected a main destabilization mechanism by creaming. The passing of the emulsion through a high‐pressure homogenizer (HPH) significantly delayed the creaming process.

Vegetable Oil-Loaded Nanocapsules: Innovative Alternative for Incorporating Drugs for Parenteral Administration.

An innovative nanocapsule formulation for parenteral administration using selected vegetable oils (mango, jojoba, pequi, oat, annatto, calendula, and chamomile) was developed that has the potential to encapsulate various drugs. The vegetable oil-loaded nanocapsules were prepared by interfacial deposition and compared with capric/caprylic triglyceride-loaded lipid core nanocapsules. The major objective was to investigate the effect of vegetable oils on particle size distribution and physical stability and to determine the hemolytic potential of the nanocapsules, considering their applicability for intravenous administration. Taking into account the importance of accurately determining particle size for the selected route of administration, different size characterization techniques were employed, such as Laser Diffraction, Dynamic Light Scattering, Multiple Light Scattering, Nanoparticle Tracking Analysis, and Transmission Electronic Microscopy. Laser diffraction studies indicated that the mean particle size of all nanocapsules was below 300 nm. For smaller particles, the laser diffraction and multiple light scattering data were in agreement (D[3,2]-130 nm). Dynamic light scattering and nanoparticle tracking analysis, two powerful techniques that complement each other, exhibited size values between 180 and 259 nm for all nanoparticles. Stability studies demonstrated a tendency of particle creaming for jojoba-nanocapsules and sedimentation for the other nanoparticles; however, no size variation occurred over 30 days. The hemolysis test proved the hemocompatibility of all nanosystems, irrespective of the type of oil. Although all developed nanocapsules presented the potential for parenteral administration, jojoba oil-loaded nanocapsules were selected as the most promising nanoformulation due to their low average size and high particle size homogeneity.

A New Methodology for Measuring the Stability of Emulsion Polymer Particles

SummaryA new methodology for the rapid and robust evaluation of the electrostatic stabilization of latex particles has been developed. It is based on the interpretation of the backscattering profile obtained using a Turbiscan Lab®. The experimental approach employs Multiple Light Scattering (MLS) in agitated measurement cells so the colloidal stability study can be performed at moderate concentration of latexes particles. Coalescence of the latex particles at different volume fraction was provoked by the addition of an aliquot of a concentrated solution of monovalent electrolyte (NaCl). The backscattering spectra were treated in order to follow the variation of the stability as a function of salt concentration, and from this variation to identify the critical coagulation concentration (CCC) of the system under investigation, in a rapid and robust manner.