The well-known discrepancy in the muon
g
− 2 between experiment and theory demands further theory investigations in view of the upcoming new experiments. One of the leading uncertainties lies in the ...hadronic light-by-light scattering contribution (HLbL), that we address with our position-space approach. We focus on exploratory studies of the pion-pole contribution in a simple model and the fermion loop without gluon exchanges in the continuum and in infinite volume. These studies provide us with useful information for our planned computation of HLbL in the muon
g
− 2 using full QCD.
This review covers the progress of light scattering applications in the field of particle characterization in the past decade. The review addresses static light scattering （the measurement of ...scattering intensities due to light-particle interaction at various spatial locations）, dynamic light scattering （the measurement of scattering due to light-particle interaction as a function of time）, and scattering tracking analysis （the tracking of particle movement through scattering measurement）.
Speech droplets generated by asymptomatic carriers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are increasingly considered to be a likely mode of disease transmission. Highly ...sensitive laser light scattering observations have revealed that loud speech can emit thousands of oral fluid droplets per second. In a closed, stagnant air environment, they disappear from the window of view with time constants in the range of 8 to 14 min, which corresponds to droplet nuclei of ca. 4 μm diameter, or 12- to 21-μm droplets prior to dehydration. These observations confirm that there is a substantial probability that normal speaking causes airborne virus transmission in confined environments.
Ocean optics is a branch of oceanography which is firmly embedded in studies of a great variety of ocean science and engineering questions. The interactive nature between radiative transfer of light ...and various dissolved and particulate constituents of seawater is at the core of ocean optics science and applications. The transfer of radiant solar energy has vital implications to life and climate on Earth, and the large variety of subjects of ocean optics ranges from the subtle problems of physical optics to optical remote sensing towards a better understanding of ocean biology, biogeochemistry and ecosystems and their roles in the Earth's system processes. The intention of this book is to present a collection of papers that generally share a common denominator of frontier topics in ocean optics which are unique, uncommon or outstanding in the literature, and to provide a balanced view of the extraordinary breadth of research in this field. Topics as diverse as measurements and modeling of radiative transfer, light fields, light scattering and polarization, ocean color, benthic optical properties, and the use of optics for characterizing seawater constituents are addressed in this book. The book is expected to be of interest and useful to a broad audience of professional ocean scientists, engineers and advanced students with an interest in ocean optics and applications of optical methods in oceanography.
Abstract After briefly introducing the theoretical equations for DLS based particle size analysis, the need for angular dependent DLS investigations is emphasized to obtain correct particle sizes. ...Practical examples are given that demonstrate the possible magnitudes of errors in particle size if DLS is measured at one large scattering angle, only, as done by essentially all, most frequently utilized commercial “single angle” particle sizers. The second part is focused on a novel DLS application to sensitively trace (nano)particle interactions with concentrated blood serum or plasma that leads to the formation of large aggregates in a size regime of ≫100 nm. Most likely, such aggregates originate from protein induced bridging of nanoparticles, since it is well known that serum proteins adsorb onto the surface of essentially all nanoparticles utilized in medical applications. Thus, the protein corona around nanoparticles does not only change their biological identity but to a large extend also their size, thus possibly affecting biodistribution and in vivo circulation time.
Hydrodynamic and light scattering methods are urgently required for accurate characterization of nanoparticles (NPs) in the field of nanomedicine to unveil their sizes and distributions. A ...fundamental characterization approach in the field of nanomedicines is, next to standard batch dynamic light scattering (DLS) and increasingly more applied (asymmetrical flow) field-flow fractionation (FFF) coupled to multi-angle laser light scattering (MALLS), the utilization of an analytical ultracentrifuge (AUC). Here, we demonstrate the power of an AUC in comparison to batch DLS and FFF-MALLS to decipher, in detail, the size and dispersity of pharma-relevant, commercial and in-house prepared soft matter NPs, suitable for life science applications. In this study, size and dispersity of poly(lactic-co-glycolic acid) (PLGA) NPs and in-house prepared NPs, consisting of the commercially available pharmapolymer Eudragit® E or of a polymer of similar composition synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization, were investigated. Simultaneously, an insight on the presence of the utilized surfactant on the NP formulations, which is usually limited with other techniques, could be achieved by multi-speed experiments with the AUC in one experimental setting. While the repeatability and ruggedness of observations with modern AUC instruments of the newest generation is demonstrated, the results are further underpinned by the classical relations of hydrodynamics. Investigations aiming at hydrodynamic diameters (from DLS) and radii of gyration (from FFF-MALLS) are critically discussed and compared to the repeatable and rugged investigations by an AUC. The latter is proven to provide a self-sufficient experimental approach for NP characterization in the field of nanomedicine based on absolute principles, compares well to FFF-MALLS, and can unravel issues in NP sizing that arise when more common techniques, such as DLS, are used.
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•Medical applications of nanoparticles (NPs) are dependent on their sizes and charge.•Determination of accurate NP size and dispersity are urgently required.•Comparison of high-end hydrodynamic, separation, and light scattering techniques.•Ruggedness and repeatability of analytical ultracentrifuge experiments.•Limits of standard and advanced techniques are discussed on par to each other.
Scattering techniques represent non-invasive experimental approaches and powerful tools for the investigation of structure and conformation of biomaterial systems in a wide range of distances, ...ranging from the nanometric to micrometric scale. More specifically, small-angle X-rays and neutron scattering and light scattering techniques represent well-established experimental techniques for the investigation of the structural properties of biomaterials and, through the use of suitable models, they allow to study and mimic various biological systems under physiologically relevant conditions. They provide the ensemble averaged (and then statistically relevant) information under in situ and
conditions, and represent useful tools complementary to the various traditional imaging techniques that, on the contrary, reveal more local structural information. Together with the classical structure characterization approaches, we introduce the basic concepts that make it possible to examine inter-particles interactions, and to study the growth processes and conformational changes in nanostructures, which have become increasingly relevant for an accurate understanding and prediction of various mechanisms in the fields of biotechnology and nanotechnology. The upgrade of the various scattering techniques, such as the contrast variation or time resolved experiments, offers unique opportunities to study the nano- and mesoscopic structure and their evolution with time in a way not accessible by other techniques. For this reason, highly performant instruments are installed at most of the facility research centers worldwide. These new insights allow to largely ameliorate the control of (chemico-physical and biologic) processes of complex (bio-)materials at the molecular length scales, and open a full potential for the development and engineering of a variety of nano-scale biomaterials for advanced applications.
Protein-protein interactions (PPI) and solution viscosities were measured at low and high protein concentrations under a range of formulation conditions for 4 different monoclonal antibodies. Static ...light scattering was used to quantify the osmotic second virial coefficient (B
) and the zero-q limit static structure factor (S
), versus protein concentration (c
) from low to high c
. Dynamic light scattering was used to measure the collective diffusion coefficient as a function of c
and to determine the protein interaction parameter (k
). Static light scattering and dynamic light scattering were combined to determine the hydrodynamic factor (H
), which accounts for changes in hydrodynamic PPI as a function of c
. The net PPI ranged from strongly repulsive to attractive interactions, via changes in buffer pH, ionic strength, and choice of monoclonal antibodies. Multiple-particle tracking microrheology and capillary viscometery were used to measure monoclonal antibodies solution viscosities under the same solution conditions. In most cases, even large and qualitative changes in PPI did not result in significant changes in protein solution viscosity. This highlights the complex nature of PPI and how they influence protein solution viscosity and raises questions as to the validity of using experimental PPI metrics such as k
or B
as predictors of high viscosity.
Multiple light scattering is considered as the major limitation for deep imaging and focusing in turbid media. In this paper, we present an innovative method to overcome this limitation and enhance ...the delivery of light energy ultra-deep into turbid media with significant improvement in focusing. Our method is based on a wide-field reflection matrix optical coherence tomography (RM-OCT). The time-reversal decomposition of the RM is calibrated with the Tikhonov regularization parameter in order to get more accurate reversal results deep inside the scattering sample. We propose a concept named model energy matrix, which provides a direct mapping of light energy distribution inside the scattering sample. To the best of our knowledge, it is the first time that a method to measure and quantify the distribution of beam intensity inside a scattering sample is demonstrated. By employing the inversion of RM to find the matched wavefront and shaping with a phase-only spatial light modulator, we succeeded in both focusing a beam deep (~9.6 times of scattering mean free path, SMFP) inside the sample and increasing the delivery of light energy by an order of magnitude at an ultra-deep (~14.4 SMFP) position. This technique provides a powerful tool to understand the propagation of photon in a scattering medium and opens a new way to focus light inside biological tissues.
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