Spores of puffball fungus Lycoperdon pyriforme as a reference standard of stable monodisperse aerosol for calibration of optical instruments

Advanced air quality control requires real-time monitoring of particulate matter size and concentration, which can only be done using optical instruments. However, such techniques need regular calibration with reference samples. In this study, we suggest that puffball fungus (Lycoperdon pyriforme) spores can be utilized as a reference standard having a monodisperse size distribution. We compare the Lycoperdon pyriforme spores with the other commonly used reference samples, such as Al2O3 powder and polystyrene latex (PSL) microspheres. Here we demonstrate that the puffball spores do not coagulate and, thus, maintain the same particle size in the aerosol state for at least 15 minutes, which is enough for instrument calibration. Moreover, the puffball mushrooms can be stored for several years and no agglomeration of the spores occurs. They are also much cheaper than other calibration samples and no additional devices are needed for aerosol generation since the fungal fruiting body acts as an atomizer itself. The aforementioned features make the fungal spores a highly promising substance for calibration and validation of particle size analyzers, which outperforms the existing, artificially produced particles for aerosol sampling. Furthermore, the L. pyriforme spores are convenient for basic research and development of new optical measurement techniques, taking into account their uniform particle size and absent coagulation in the aeroso

Ultrasonic dispersion of agglomerated particles in metal melt

This work considers the deagglomeration and wettability of particles by metal melt and proposes a mechanism of particle agglomerate dispersion by ultrasonic cavitation. The main dependences connecting the processing time and intensity with the physical and chemical properties of particles and the melt as well as acoustic parameters are obtained. For the first time found that melt during ultrasonic treatment, inclusive the particles agglomerates proportional to melt viscosity and the size of the agglomerates. It has been established that time ultrasonic treatment melt containing the particles agglomerates is proportional to melt viscosity and the size of the agglomerates. The required time for successful melt infiltration in the agglomerates, wettability and their introduction into the melt takes ten minutes. The suggested equation allows estimating the intensity of ultrasonic radiation, required to destroy the agglomerates of particles in the melt. It was found that intensity of the ultrasound must be inversely proportional to the radius of the agglomerates. The theoretical results are confirmed by comparing with experimental dates

Mechanisms of acoustic processing of a metal melt containing nanoparticles

Wave processing with the frequencies from subsound (vibration) to ultrasound is used to produce nanopowder-modified composite alloys. This work considers mechanisms of such processing of metal melts, which lead to deagglomeration and wettability of particles of a metal melt and to the destruction of growing crystals during solidification. The main dependences for the threshold of the turbulence and cavitation were obtained. Resonance phenomena that contribute to positive changes in the melt are discussed. Possible mechanisms of the destruction of growing crystals and agglomerates of particles at the high-frequency processing of the melt are considered, including the destruction of agglomerates in the front of an acoustic wave and the destruction of crystals by oscillating solid particles

Theoretical and experimental investigations of the process of vibration treatment of liquid metals containing nanoparticles

It is known that the use of external effects, such as acoustic fields (from ultrasonic to low-frequency range), help in breaking down agglomerates, improving particle wettability, providing uniform particle distribution in the melt volume, and reducing the grain size. The fragmentation of growing crystals, de-agglomeration of particles and their mixing in liquid metal under the influence of vibration (with frequencies of 10–100 Hz) are considered in this paper. The major advantage of such a technique in comparison with high-frequency methods (sonic, ultrasonic) is the capability of processing large melt volumes proportional to the wavelength. The mechanisms of the breaking down of particle agglomerates and the mixing of particles under conditions of cavitation and turbulence during the vibration treatment of the melt are considered. Expressions linking the threshold intensity and frequency with the amplitude necessary to activate mechanisms of turbulence and cavitation were obtained. The results of vibration treatment experiments for an aluminum alloy containing diamond nanoparticles are given. This treatment makes it possible to significantly reduce the grain size and to improve the casting homogeneity and thus improve the mechanical properties of the alloy

Ultrasonic impact on a metal melt containing electrostaticly charged nanoparticles

Ultrasonic processing is applied to modify nanopowders of metals for the creation of composition alloys. The introduction of particles to metal is prevented by their low wettability in the metal melt. We use electrostatic charging of particles to increase the wettability of particles and to prevent their agglomeration. Mechanisms of the ultrasonic impact on melts of metals containing charged nanoparticles are considered. We find that an electric charge of the surface leads to a decrease in the contact angle. Expressions for the time of ultrasonic processing depending on physical and chemical characteristics of particles and the melt are found

Creation of development zones in the Arctic: methodology and practice

The article describes the basic principles and methodological bases of formation and development of the supporting areas of the Russian Arctic. The work emphasizes that the basis of the methodological approach in the formation of the supporting areas is a vector of development of the territory as an integral project on the principle of coordination of all "industrial" activities in the planning, goal-setting, financing and implementation, which will allow to reduce all kinds of costs and expenses, as well as all the projects included in the supporting areas should be aimed at the development of the macro-region as a whole, not just to solve individual tasks of the industry. The article underlines that the formation of the supporting areas is aimed at achieving a single global goal — to encourage efficiency and diversification of the economy of the Arctic zone, oriented to the preservation and development of the Northern Sea Route

Preclinical models for prediction of immunotherapy outcomes and immune evasion mechanisms in genetically heterogeneous multiple myeloma

The historical lack of preclinical models reflecting the genetic heterogeneity of multiple myeloma (MM) hampers the advance of therapeutic discoveries. To circumvent this limitation, we screened mice engineered to carry eight MM lesions (NF-κB, KRAS, MYC, TP53, BCL2, cyclin D1, MMSET/NSD2 and c-MAF) combinatorially activated in B lymphocytes following T cell-driven immunization. Fifteen genetically diverse models developed bone marrow (BM) tumors fulfilling MM pathogenesis. Integrative analyses of ∼500 mice and ∼1,000 patients revealed a common MAPK-MYC genetic pathway that accelerated time to progression from precursor states across genetically heterogeneous MM. MYC-dependent time to progression conditioned immune evasion mechanisms that remodeled the BM microenvironment differently. Rapid MYC-driven progressors exhibited a high number of activated/exhausted CD8+ T cells with reduced immunosuppressive regulatory T (Treg) cells, while late MYC acquisition in slow progressors was associated with lower CD8+ T cell infiltration and more abundant Treg cells. Single-cell transcriptomics and functional assays defined a high ratio of CD8+ T cells versus Treg cells as a predictor of response to immune checkpoint blockade (ICB). In clinical series, high CD8+ T/Treg cell ratios underlie early progression in untreated smoldering MM, and correlated with early relapse in newly diagnosed patients with MM under Len/Dex therapy. In ICB-refractory MM models, increasing CD8+ T cell cytotoxicity or depleting Treg cells reversed immunotherapy resistance and yielded prolonged MM control. Our experimental models enable the correlation of MM genetic and immunological traits with preclinical therapy responses, which may inform the next-generation immunotherapy trials

Symmetry in Aerosol Mechanics: Review

The present review is concerned with the motion of aerosol particles, including that under the exposure to external fields, with special focus being put on the problems related to the similarity theory and invariants that manifest themselves as symmetry in physics. Research on the mechanics of aerosols is extremely important for managing environmental practices. Ultrasonic and electrostatic effects are used in technological processes for cleaning industrial aerosol emissions. In addition, aerosol systems are commonly used to prevent emergency situations (fire extinguishing, fog deposition). Understanding these processes requires knowledge of aerosol mechanics. At the same time, fundamental laws of particulate matter behavior have not been established until now, especially in the presence of external fields. In this paper, we consider the main similarity criteria that are applied for aerosol description. The motion of aerosol particles in the gravitational, electric, and ultrasonic fields is described. The results from studies into acoustic and electrostatic aerosol coagulations are presented herein

Symmetry in Aerosol Mechanics: Review

The present review is concerned with the motion of aerosol particles, including that under the exposure to external fields, with special focus being put on the problems related to the similarity theory and invariants that manifest themselves as symmetry in physics. Research on the mechanics of aerosols is extremely important for managing environmental practices. Ultrasonic and electrostatic effects are used in technological processes for cleaning industrial aerosol emissions. In addition, aerosol systems are commonly used to prevent emergency situations (fire extinguishing, fog deposition). Understanding these processes requires knowledge of aerosol mechanics. At the same time, fundamental laws of particulate matter behavior have not been established until now, especially in the presence of external fields. In this paper, we consider the main similarity criteria that are applied for aerosol description. The motion of aerosol particles in the gravitational, electric, and ultrasonic fields is described. The results from studies into acoustic and electrostatic aerosol coagulations are presented herein