Ultrasound assisted extraction of food and natural products. Mechanisms, techniques, combinations, protocols and applications. A review.

Early indicators for nanoparticle-derived adverse health effects should provide a relative measure for cytotoxicity of nanomaterials in comparison to existing toxicological data. We have therefore evaluated a human mesothelioma and a rodent fibroblast cell line for in vitro cytotoxicity tests using seven industrially important nanoparticles. Their response in terms of metabolic activity and cell proliferation of cultures exposed to 0−30 ppm nanoparticles (μg g-1) was compared to the effects of nontoxic amorphous silica and toxic crocidolite asbestos. Solubility was found to strongly influence the cytotoxic response. The results further revealed a nanoparticle-specific cytotoxic mechanism for uncoated iron oxide and partial detoxification or recovery after treatment with zirconia, ceria, or titania. While in vitro experiments may never replace in vivo studies, the relatively simple cytotoxic tests provide a readily available pre-screening method.

In Vitro Cytotoxicity of Oxide Nanoparticles: Comparison to Asbestos, Silica, and the Effect of Particle Solubility†

Flame aerosol synthesis of ceramic powders

Author(s): Aldous, DJ | Abstract: Consider N particles, which merge into clusters according to the following rule: a cluster of size x and a cluster of size y merge at (stochastic) rate K(x, y)/N, were AT is a specified rate kernel. This Marcus-Lushnikov model of stochastic coalescence and the underlying deterministic approximation given by the Smoluchowski coagulation equations have an extensive scientific literature. Some mathematical literature (Kingman's coalescent in population genetics; component sizes in random graphs) implicitly studies the special cases K(x, y) = 1 and K(x, y) = xy. We attempt a wide-ranging survey. General kernels are only now starting to be studied rigorously; so many interesting open problems appear. © 1999 ISI/BS.

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Deterministic and stochastic models for coalescence (aggregation and coagulation): a review of the mean-field theory for probabilists

Recent advances in aerosol generation of materials are reviewed Gas-to-particle and spray processes (spray pyrolysis) for powder generation and various routes for film generation are discussed from the experimental and theoretical perspectives The range of materials generated by these routes has increased in recent years to include fullerenes and ceramic superconductors Many metals and various oxide and nonoxide ceramics have also been added to the list of materials generated by gas-phase routes Established aerosol routes such as vapor condensation have found widespread applications for generation of nanophase materials The formation of quantum dots via aerosol approaches has also been demonstrated The theoretical understanding of gas-to-particle conversion routes has advanced to include the finite rate of particle fusion or sintering occurring after collisions of particles The modeling of spray pyrolysis systems has provided insight into the control of particle morphology and reactor design In th

https://www.tandfonline.com/doi/pdf/10.1080/02786829308959650

Aerosol Processing of Materials

A simple model describing the evolution of particle morphology, size, and number concentration by coagulation and sintering is presented that neglects the spread of the polydispersity of aggregate and primary particles. The influence of irregular/fractal structure on the collision kernel is accounted for, from the free molecular to the continuum regime. The model predictions compare well to those of a detailed two-dimensional sectional model of nonspherical particle dynamics. After a theoretical evaluation of the main sintering mechanism, the proposed model was applied to laser synthesis of silicon in an aerosol reactor.

https://www.tandfonline.com/doi/pdf/10.1080/02786829308959656

Karl A. Kusters

Papers

A Simple Model for the Evolution of the Characteristics of Aggregate Particles Undergoing Coagulation and Sintering

Ultrasonic fragmentation of agglomerate powders

Time-Lag for Attainment of the Self-Preserving Particle Size Distribution by Coagulation

Energy—size reduction laws for ultrasonic fragmentation

Strategies for control of ceramic powder synthesis by gas-to-particle conversion