Identification of extracellular nanoparticle subsets by nuclear magnetic resonance

Exosomes are a subset of secreted lipid envelope-encapsulated extracellular vesicles (EVs) of 50–150 nm diameter that can transfer cargo from donor to acceptor cells. In the current purification protocols of exosomes, many smaller and larger nanoparticles such as lipoproteins, exomers and microvesicles are typically co-isolated as well. Particle size distribution is one important characteristics of EV samples, as it reflects the cellular origin of EVs and the purity of the isolation. However, most of the physicochemical analytical methods today cannot illustrate the smallest exosomes and other small particles like the exomers. Here, we demonstrate that diffusion ordered spectroscopy (DOSY) nuclear magnetic resonance (NMR) method enables the determination of a very broad distribution of extracellular nanoparticles, ranging from 1 to 500 nm. The range covers sizes of all particles included in EV samples after isolation. The method is non-invasive, as it does not require any labelling or other chemical modification. We investigated EVs secreted from milk as well as embryonic kidney and renal carcinoma cells. Western blot analysis and immuno-electron microscopy confirmed expression of exosomal markers such as ALIX, TSG101, CD81, CD9, and CD63 in the EV samples. In addition to the larger particles observed by nanoparticle tracking analysis (NTA) in the range of 70–500 nm, the DOSY distributions include a significant number of smaller particles in the range of 10–70 nm, which are visible also in transmission electron microscopy images but invisible in NTA. Furthermore, we demonstrate that hyperpolarized chemical exchange saturation transfer (Hyper-CEST) with ¹²⁹Xe NMR indicates also the existence of smaller and larger nanoparticles in the EV samples, providing also additional support for DOSY results. The method implies also that the Xe exchange is significantly faster in the EV pool than in the lipoprotein/exomer pool.

Diffusion and xenon NMR based methods to determine a very broad range of sizes and sub-sets of extracellular vesicles.     

Asymptotic multiphase Σ-solutions to the singularly perturbed Korteweg–de Vries equation with variable coefficients

The paper deals with constructing the asymptotic solution to the singularly perturbed Korteweg–de Vries equation with variable coefficients. The notion of an asymptotic multiphase Σ-solution is proposed, and an algorithm of its construction in a neighborhood of the point t = 0 is given. Some theorems concerning the exactness, with which such local asymptotic solution satisfies the equation under study are proved.     

The studies of structural aspects of the cluster formation in silicate glasses doped with cerium and titanium oxides by small-angle neutron scattering

The structural aspects of the formation of Ti-Ce-O nanoclusters in silicate glasses doped with oxides TiO₂ and CeO₂ have been studied by means of small-angle neutron scattering. It has been obtained that, in such glasses, complex oxide nanoclusters with sizes of 300–380 Å are formed; their average size increases and the fractal dimension is changed as the concentration of the initial oxides increases. Correlation between the structural characteristics of the nanoclusters and the optical properties of the doped silicate glasses is discussed.     

Investigation of the decay η′ → 3 π 0 with the GAMS-4π spectrometer

An experiment performed with the GAMS-4π spectrometer resulted in observing 235 ± 45 events of the decay η′ → 3π ⁰. The respective charge-exchange reaction at a momentum of 32.5 GeV/c was used as a source of η′ mesons. The decay branching ratio was found to be Br(η′ → 3π ⁰) = (1.8 ± 0.4) × 10^?3. The slope parameter of the square of the respective matrix element in the linear approximation proved to be β = ?0.59 ± 0.18.     

Partial-wave analysis of the ωπ0-system at high masses

A partial-wave analysis of the ω ωπ⁰-system produced in the π^- p→ωπ⁰ n reaction at 38 GeV/c beam momentum has been performed. A new 5^?- meson state,ρ ₅(22350), with a massM=2330±35 MeV and a width Γ=400±100 MeV, is observed. The analysis also confirms the 1^?- ρ(2150) meson, a radial-orbital excitation of the ρ(770), observed earlier by the GAMS Collaboration.     

Calculating the Parameters of the Biphoton Radiation Source in a Wide Wavelength Range

Optics and Spectroscopy - In this paper, we develop a constructive algorithm to determine the parameters of a nonlinear crystal for generating correlated photons in a given wavelength range using...     

Studies of the reactionπ − p→η ′ π 0 n at 38 and 100 GeV/c

The production of ⁰ system in ^– _p charge-exchange interactions at ^– momenta 38 GeV/c and 100 GeV/c has been studied. The 2 and ^{0 0} decay modes of leading to 4 and 8 final states respectively have been detected. No statistically significant peak is observed in the ⁰ mass spectrum in the range of 1.2 GeV÷2.1 GeV. An upper limit of 6·10^–3 has been established for thea ₂ ⁰ (1320) ⁰ branching ratio.     

Modernization and Methods of Maintaining the Operating Mode of the OGRAN (Optoacoustic Gravity Antenna) Setup

Physics of Atomic Nuclei - An upgraded version of the combined optoacoustic gravitational radiation detector OGRAN is considered. This underground setup located at the Baksan Neutrino Observatory...