Microorganisms are ubiquitous in the environment. Wherever their sources are present, the particles can be released into the air forming microbiological aerosols. Although most of their particles cause no harm to the exposed individuals, some of their propagules may have infectious or allergenic potential and may carry toxic or irritant substances and components. Their inhalation usually poses a significant health risk and is responsible for numerous adverse outcomes, from allergic reactions, infections and toxic responses to various nonspecific symptoms. This review article provides fundamental background information on the role of microorganisms in the environment, defines and characterizes environmental sources of microbial aerosols, describes microbial abilities for airborne transport and comments on their role in atmospheric processes, discusses their physical and biological characteristics which result in adverse health outcomes observed in exposed individuals. The paper characterizes comprehensively numerous sampling and analysis techniques involved in the quantitative and qualitative evaluation of microbial aerosols together with their practical applications, presents strategies applied in the assessment of harmful microbial agents formed by bioaerosols, explains the ways of creating hygienic standards (understood here as reference/threshold limits) for microbiological aerosols conditioned by both medical and environmental determinants, and comments on their usefulness in the control and protection of environment and health.

A continuous flow reaction process in which a metal salt solution is rapidly mixed with high-temperature water was employed to achieve rapid heating up to supercritical conditions. A quarter of a century has passed since the supercritical hydrothermal method was first proposed. This paper introduces recent advances in science and technology related to the supercritical process. Process design, kinetics, reaction atmosphere (redox) control, morphology control, organic modification of particles, nanocatalysts, and organic-inorganic hybrid materials are reviewed for promising applications of the supercritical process.

Researches relating dust collector using fiber as particle collection body i.e., air filter, cartridge filter and nonwoven bag filter, were reviewed. Their filtration process was classified into 3 stages, i.e., Stage 1. inner filtration I, Stage 2. inner filtration II and Stage 3. surface filtration. Collection mechanisms of fresh circular fiber have been well understood and so-called classic filtration theory is applicable except single nano-particle, where discussion about the possibility of thermal rebound is necessary. In Stage 1, effects of shape of both fiber and particle, and filter structure, non-uniformity are the important issues. In Stages 2 and 3, filtration process becomes very complicated because of many affecting parameters. Main target in Stage 2 is to develop effective scheme to describe the phenomena and to find filter structure having a large holding capacity. Most important issue in Stage 3 is to develop the effective cleaning technique to minimize the dust emission based on rational but not empirical scheme.

Significant progress has been made over the last half-century in delivering therapeutics by the pulmonary route. Inhaled therapeutics are administered to humans using metered-dose inhalers, nebulizers, or dry powder inhalers, and each device requires a different formulation strategy for the therapeutic to be successfully delivered into the lung. In recent years, there has been a shift to the use of dry powder inhalers due to advantages in the consistency of the dose delivered, ease of administration, and formulation stability. Numerous preclinical studies, involving small and large animals, have evaluated dry powder drugs, vaccines, and immunotherapeutics delivered by the pulmonary route. These studies used different dry powder delivery devices including nose-only, whole-body, and intratracheal administration systems, each of which works with different aerosolization mechanisms. Unfortunately, these delivery platforms usually lead to variable powder deposition in the respiratory tract of animals. In this review, we will discuss obstacles and variables that affect successful pulmonary delivery and uniform powder deposition in the respiratory tract, such as the type of delivery device, dry powder formulation, and the animal model used. We will conclude by outlining factors that enhance the reproducible deposition of dry powders in the respiratory tract of preclinical animal models and identifying knowledge and technology gaps within the field. We will also outline the important factors necessary for successful translation of studies performed in preclinical models to humans.

Emulsion—a liquid dispersed in another liquid—is in many respects very similar to granular matter. In the early 2000s a new technology—droplet microfluidics—began emerging from the wider field of microfluidics. Droplet microfluidics was quickly established as a discipline of science and engineering and has been used for the generation of highly uniform emulsions. The last few years have brought significant advances to the field, directed towards a wide range of applications in material sciences—from synthesis of nanoparticles in droplets to assembling complex droplets and using droplets as templates for ordered materials, with applications in food, cosmetic and diagnostic industries. Droplet microfluidic platforms are also successfully used as analytical tools in molecular biology and biochemistry, in e.g. high-throughput screening, digital assays, encapsulation of single cells, sequencing technologies, and in point-of-care diagnostic applications. This article provides an accessible overview of the physical phenomena observed in multiphase flow at the microscale and the techniques in droplet microfluidics systems. We also present the most interesting applications and potential further directions of research in this fascinating young field of science and engineering.