Mouse innate-like B-1 lymphocytes promote inhaled particle-induced in vitro granuloma formation and inflammation in conjunction with macrophages

The current paradigm for explaining lung granulomatous diseases induced by inhaled particles is mainly based on macrophages. This mechanism is now challenging because B lymphocytes also infiltrate injured tissue, and the deficiency in B lymphocytes is associated with limited lung granulomas in silica-treated mice. Here, we investigated how B lymphocytes respond to micro- and nanoparticles by combining in vivo and in vitro mouse models. We first demonstrated that innate-like B-1 lymphocytes (not conventional B-2 lymphocytes or plasma cells) specifically accumulated during granuloma formation in mice instilled with crystalline silica (DQ12, 2.5 mg/mouse) and carbon nanotubes (CNT Mitsui, 0.2 mg/mouse). In comparison to macrophages, peritoneal B-1 lymphocytes purified from naïve mice were resistant to the pyroptotic activity of reactive particles (up to 1 mg/mL) but clustered to establish in vitro cell/particle aggregates. Mouse B-1 lymphocytes (not B-2 lymphocytes) in coculture with macrophages and CNT (0.1 µg/mL) organized three-dimensional spheroid structures in Matrigel and stimulated the release of TIMP-1. Furthermore, purified B-1 lymphocytes are sensitive to nanosilica toxicity through radical generation in culture. Nanosilica-exposed B-1 lymphocytes released proinflammatory cytokines and alarmins. In conclusion, our data indicate that in addition to macrophages, B-1 lymphocytes participate in micrometric particle-induced granuloma formation and display inflammatory functions in response to nanoparticles.

A Review of Microbial Decontamination of Cereals by Non-Thermal Plasma

Cereals, an important food for humans and animals, may carry microbial contamination undesirable to the consumer or to the next generation of plants. Currently, non-thermal plasma (NTP) is often considered a new and safe microbicidal agent without or with very low adverse side effects. NTP is a partially or fully ionized gas at room temperature, typically generated by various electric discharges and rich in reactive particles. This review summarizes the effects of NTP on various types of cereals and products. NTP has undisputed beneficial effects with high potential for future practical use in decontamination and disinfection.

Investigation of the Cause-Effect Relationships between the Exothermic Reaction and the Microstructures of Reactive Ni-Al Particles Produced by High Energy Planetary Ball Milling

Reactive particles consisting of nickel and aluminum represent an adaptable heat source for joining applications, since each individual particle is capable of undergoing a self-sustaining exothermic reaction. Of particular interest are particles with intrinsic lamellar microstructures, as they provide large contact areas between the reactants nickel and aluminum. In this work, the exothermic reaction as well as the microstructure of such lamellar reactive particles produced by high energy planetary ball milling were investigated. Based on statistically designed experiments regarding the milling parameters, the heat of reaction was examined by means of differential scanning calorimetry (DSC). A statistical model was derived from the results to predict the heat of reaction as a function of the milling parameters used. This model can be applied to adjust the heat of reaction of the reactive particles depending on the thermal properties of the joining partners. The fabricated microstructures were evaluated by means of scanning electron microscopy (SEM). Through the development of a dedicated SEM image evaluation algorithm, a computational quantification of the contact area between nickel and aluminum was enabled for the first time. A weak correlation between the contact area and the heat of reaction could be demonstrated. It is assumed that the quantification of the contact areas can be further improved by a higher number of SEM images per sample. The findings obtained provide an essential contribution to enable reactive particles as a tailored heat source for joining applications.

Numerical Evaluation of the Use of Aluminum Particles for Enhancing Solid Rocket Motor Combustion Stability

The ability to predict the expected internal behaviour of a given solid-propellant rocket motor under transient conditions is important. Research towards predicting and quantifying undesirable transient axial combustion instability symptoms typically necessitates a comprehensive numerical model for internal ballistic simulation under dynamic flow and combustion conditions. On the mitigation side, one in practice sees the use of inert or reactive particles for the suppression of pressure wave development in the motor chamber flow. With the focus of the present study placed on reactive particles, a numerical internal ballistic model incorporating relevant elements, such as a transient, frequency-dependent combustion response to axial pressure wave activity above the burning propellant surface, is applied to the investigation of using aluminum particles within the central internal flow (particles whose surfaces nominally regress with time, as a function of current particle size, as they move downstream) as a means of suppressing instability-related symptoms in a cylindrical-grain motor. The results of this investigation reveal that the loading percentage and starting size of the aluminum particles have a significant influence on reducing the resulting transient pressure wave magnitude.

Numerical Evaluation of the Use of Aluminum Particles for Enhancing Solid Rocket Motor Combustion Stability

The ability to predict the expected internal behaviour of a given solid-propellant rocket motor under transient conditions is important. Research towards predicting and quantifying undesirable transient axial combustion instability symptoms typically necessitates a comprehensive numerical model for internal ballistic simulation under dynamic flow and combustion conditions. On the mitigation side, one in practice sees the use of inert or reactive particles for the suppression of pressure wave development in the motor chamber flow. With the focus of the present study placed on reactive particles, a numerical internal ballistic model incorporating relevant elements, such as a transient, frequency-dependent combustion response to axial pressure wave activity above the burning propellant surface, is applied to the investigation of using aluminum particles within the central internal flow (particles whose surfaces nominally regress with time, as a function of current particle size, as they move downstream) as a means of suppressing instability-related symptoms in a cylindrical-grain motor. The results of this investigation reveal that the loading percentage and starting size of the aluminum particles have a significant influence on reducing the resulting transient pressure wave magnitude.

Amplitude death and restoration in networks of oscillators with random-walk diffusion

Systems composed of reactive particles diffusing in a network display emergent dynamics. While Fick’s diffusion can lead to Turing patterns, other diffusion schemes might display more complex phenomena. Here we study the death and restoration of collective oscillations in networks of oscillators coupled by random-walk diffusion, which modifies both the original unstable fixed point and the stable limit-cycle, making them topology-dependent. By means of numerical simulations we show that, in some cases, the diffusion-induced heterogeneity stabilizes the initially unstable fixed point via a Hopf bifurcation. Further increasing the coupling strength can moreover restore the oscillations. A numerical stability analysis indicates that this phenomenology corresponds to a case of amplitude death, where the inhomogeneous stabilized solution arises from the interplay of random walk diffusion and heterogeneous topology. Our results are relevant in the fields of epidemic spreading or ecological dispersion, where random walk diffusion is more prevalent.