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How Nanoparticles Are Generated
Published in Antonietta Morena Gatti, Stefano Montanari, Advances in Nanopathology From Vaccines to Food, 2021
Antonietta Morena Gatti, Stefano Montanari
The particles we deal with and which are discussed in this book are solid and inorganic. Their size varies from a few tens of nanometres up to a few tens of microns. By official definition, nanoparticles (or ultrafine particles) have a size ranging from 1 to 100 nm. Again officially, fine particles are sized between 100 nm and 2.5 μm, while coarse particles cover a range between 2.5 and 10 μm. In our research field, that classification has no great meaning. So, in general, we call nanoparticles those whose size is smaller than 1 μm and microparticles the ones larger than that size. It is just a matter of personal habit and of convenience, which, of course, is of no consequence, though deemed important by those who approach science in a bureaucratic way.
Personal Protective Equipment (PPE): Practical and Theoretical Considerations
Published in Brian J. Lukey, James A. Romano, Salem Harry, Chemical Warfare Agents, 2019
Let us now gain a frame of reference for various-sized particles. Inhalable particles may be defined as those particles <100 μm. These particles can be inhaled through the nose and mouth; however, particles >30 μm are unlikely to be able to pass through the nasal passages. Particles must be in the order of <10 μm to be able to advance below the larynx. Respirable particles are able to penetrate into the gas-exchanging areas of the lungs (i.e., alveolar sacs) and are generally <4.0 μm or smaller. Ultrafine particles are defined as being <0.1 μm in size (nanoparticles) (Baker, 2011). Particles can adsorb volatile organic chemicals and oxidants onto their surfaces and depending on the particle size, can distribute them into various locations within the respiratory tree. Ultrafine particles (<0.1 μm) are believed to overwhelm the cleaning mechanism in the alveoli and damage the epithelial cells in the alveolar sacs, resulting in inflammation and leading to increased potential for inflammatory lung diseases, including allergies, asthma, and bronchitis (Baker, 2011) (Tables 17.3 and 17.4).
Particle deposition in the respiratory tract and the effect of respiratory disease
Published in Anthony J. Hickey, Heidi M. Mansour, Inhalation Aerosols, 2019
Early experimental studies to characterize total deposition in the respiratory tract employed light-scattering photometry and nonhygroscopic, monodisperse aerosols >0.5 µm (7) to determine fractional deposition at the mouth on a breath-by-breath basis. The total deposition of ultrafine particles was most commonly measured using condensation particle counting techniques (8,9). Besides its use to measure total deposition of inhaled aerosols, the light-scattering method has also been employed with a bolus technique to study regional airway deposition in the human lung (10). The bolus method consists of inserting a small amount of aerosol of the inhaled breath at a predetermined point in the subject’s inspiratory volume and measuring the deposition of the aerosol bolus during the subsequent expiration. The methodology assumes that a bolus inserted early in the inspiratory volume probes the lung periphery while a bolus inserted late in the inspiratory volume probes more proximal lung regions. The depth reached by the bolus is usually referred to as the penetration volume (Vp) and is defined as the volume of particle-free air inhaled from the mode of the bolus to the end of inspiration. In normal subjects, for Vp > 100 mL, aerosol bolus deposition has been shown to increase linearly with depth of inhalation of the bolus within the lung (1).
Impacts of ingested MWCNT-Embedded nanocomposites in Japanese medaka (Oryzias latipes)
Published in Nanotoxicology, 2021
Melissa Chernick, Alan Kennedy, Treye Thomas, Keana C. K. Scott, Christine Ogilvie Hendren, Mark R. Wiesner, David E. Hinton
Release of particles from nanocomposites with subsequent human exposure occurs during production and processing, service life, and disposal of products (Schlagenhauf et al. 2014). For example, 3D printers have been shown to emit large numbers of ultrafine particles (>1e + 08 particles/min) (Byrley et al. 2019). The release also happens either by high-energy machining methods post-manufacture (e.g. scratching, drilling, sanding, cutting) or by low-energy processes such as environmental degradation from UV-light and weathering (Collier et al. 2015; ERDC 2021; Haber et al. 2019; Nowack et al. 2013). Released carbon nanotubes (CNTs) are in the form of agglomerates and/or individual particles (Heitbrink and Lo 2015) and can be either matrix-bound, protuberant, or occur as free or agglomerated particles (Gottschalk and Nowack 2011; Nowack et al. 2013). To study CNT release from a polymer matrix, sanding and abrading of nanocomposites are recognized, low-energy ways that mimic consumer use patterns during product use.
Advances in understanding of mechanisms related to increased cardiovascular risk in COPD
Published in Expert Review of Respiratory Medicine, 2021
Paola Rogliani, Beatrice Ludovica Ritondo, Rossella Laitano, Alfredo Chetta, Luigino Calzetta
There is also evidence that inhaled ultrafine particles are able to freely diffuse from the lung into the systemic circulation without requiring any mediating cell [67]. Systemic inflammation could represent a hypothetical pathophysiological link between CVD and COPD, indeed it is regarded as the main risk factor for morbidity and mortality related to CVD [68]. The correlation between system inflammation and COPD should be also considered in the wider context of metabolic syndrome, a condition frequently found among individuals older than 60 years predisposed to systemic inflammation and physical inactivity. These factors may lead to vicious circle of enhanced visceral adipose tissue, adipokines, and insulin resistance that in turn further increase the level of systemic inflammation [69–71].
The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of silver nanoparticles against Staphylococcus aureus
Published in Biomaterial Investigations in Dentistry, 2020
Prashik Parvekar, Jayant Palaskar, Sandeep Metgud, Rahul Maria, Smita Dutta
In this study, MIC and MBC of silver nanoparticles against S. aureus were determined by macrodilution method and both were found to be effective at 0.625 mg/ml. (Tables 1 and 2) This is the first study in the literature to include the MBC of 5 nm silver nanoparticles against S. aureus. One study demonstrated that MIC, MBC of 10 nm silver nanoparticles is in concentrations of 1.35 mg/ml against S. aureus. [23] This variation might be due to the methodology used to prepare silver nanoparticles and the size of the silver nanoparticles used. The ultrafine particle size causes its action at lower concentration. In this study commercially available silver nanoparticle was used with the size of 5 nm. Silver nanoparticles with less than 10 nm sizes showed an enhanced antimicrobial effect in a study by Agnihotri et al. They also concluded that compared to other sizes of silver nanoparticles, 5 nm size have the fastest antibacterial activity [24].