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Scientific Reports Oct 2023The number of respiratory particles emitted during different respiratory activities is one of the main parameters affecting the airborne transmission of respiratory...
The number of respiratory particles emitted during different respiratory activities is one of the main parameters affecting the airborne transmission of respiratory pathogens. Information on respiratory particle emission rates is mostly available for adults (few studies have investigated adolescents and children) and generally involves a limited number of subjects. In the present paper we attempted to reduce this knowledge gap by conducting an extensive experimental campaign to measure the emission of respiratory particles of more than 400 children aged 6 to 12 years while they pronounced a phonetically balanced word list at two different voice intensity levels ("speaking" and "loudly speaking"). Respiratory particle concentrations, particle distributions, and exhaled air flow rates were measured to estimate the respiratory particle emission rate. Sound pressure levels were also simultaneously measured. We found out that median respiratory particle emission rates for speaking and loudly speaking were 26 particles s (range 7.1-93 particles s) and 41 particles s (range 10-146 particles s), respectively. Children sex was significant for emission rates, with higher emission rates for males during both speaking and loudly speaking. No effect of age on the emission rates was identified. Concerning particle size distributions, for both respiratory activities, a main mode at approximately 0.6 µm and a second minor mode at < 2 µm were observed, and no differences were found between males and females. This information provides important input parameters in predictive models adopted to estimate the transmission risk of airborne pathogens in indoor spaces.
Topics: Male; Adult; Female; Adolescent; Humans; Child; Particle Size; Exhalation; Air Pollution, Indoor
PubMed: 37880507
DOI: 10.1038/s41598-023-45615-0 -
Advanced Drug Delivery Reviews Apr 2024Particle-based drug delivery systems have shown promising application potential to treat human diseases; however, an incomplete understanding of their interactions with... (Review)
Review
Particle-based drug delivery systems have shown promising application potential to treat human diseases; however, an incomplete understanding of their interactions with vascular endothelium in blood flow prevents their inclusion into mainstream clinical applications. The flow performance of nano/micro-sized particles in the blood are disturbed by many external/internal factors, including blood constituents, particle properties, and endothelium bioactivities, affecting the fate of particles in vivo and therapeutic effects for diseases. This review highlights how the blood constituents, hemodynamic environment and particle properties influence the interactions and particle activities in vivo. Moreover, we briefly summarized the structure and functions of endothelium and simulated devices for studying particle performance under blood flow conditions. Finally, based on particle-endothelium interactions, we propose future opportunities for novel therapeutic strategies and provide solutions to challenges in particle delivery systems for accelerating their clinical translation. This review helps provoke an increasing in-depth understanding of particle-endothelium interactions and inspires more strategies that may benefit the development of particle medicine.
Topics: Humans; Endothelium, Vascular; Hemodynamics; Drug Delivery Systems; Particle Size
PubMed: 38387770
DOI: 10.1016/j.addr.2024.115216 -
International Journal of Environmental... Aug 2023Because of the rising environmental and health concerns associated with atmospheric pollution caused by potentially toxic elements (PTEs), several road dust studies have...
Because of the rising environmental and health concerns associated with atmospheric pollution caused by potentially toxic elements (PTEs), several road dust studies have been performed across the world in recent decades. This paper illustrates the effects of particle size on the PTE contents, mineralogical composition, environmental pollution and health risk assessments in road dust from Barcelona (Spain). The samples were sieved into five size fractions ranging from <45 to 500-800 µm. Although the major mineral contents (tectosilicates, phyllosilicates, and carbonates) were profuse in all fractions, the identified inhalable PTE particles (e.g., Fe, Cr, Cu, Zn, Ni, and REE), with size < 10 µm, were more pervasive in the finest fraction (<45 μm). This is consistent with the concentrations measured: the finest fractions were richer in PTEs than the coarser ones, resulting in a direct correlation with the enrichment factor (EF), geo-accumulation (I), and non-carcinogenic (HI) and carcinogenic (CRI) values. I and EF values can be appropriate tracers for some common elements (e.g., Zn, Sb, Sn, Cu, and Cr), but they do not seem adequate for anthropogenic particles accumulated at concentrations similar to the geogenic background. Overall, the HI and CRI values obtained in Barcelona were acceptable, reflecting no serious health impacts in the study area, except for Cr. Our results suggest that fine dust particles are a more suitable fraction to conduct pollution and health risk assessments than coarser ones, although the EF, I, HI, and CRI threshold values should be redefined in the future to include all emergent pollutants as well. In summary, monitoring programs should include at least the road dust evaluation of <45 µm particles, which can be performed with a simple sieving method, which is both time- and cost-effective.
Topics: Humans; Particle Size; Environmental Pollution; Environmental Pollutants; Carcinogenesis; Carcinogens; Dust; Risk Assessment
PubMed: 37681795
DOI: 10.3390/ijerph20176655 -
Methods in Molecular Biology (Clifton,... 2024Various nanoparticle-based delivery systems have been developed for the encapsulation and protection of active cargoes. Lipid nanoparticles represent one of the most...
Various nanoparticle-based delivery systems have been developed for the encapsulation and protection of active cargoes. Lipid nanoparticles represent one of the most widely used nanoparticle-based delivery systems for in vitro and in vivo applications, especially for the delivery of ribonucleic acid (RNA). In this chapter, a simple bulk mixing method for the encapsulation of RNA is described along with characterization techniques for measuring encapsulation efficiency and nanoparticle physicochemical properties.
Topics: Nanoparticles; RNA; Lipids; Particle Size; Liposomes
PubMed: 38907931
DOI: 10.1007/978-1-0716-3918-4_25 -
International Journal of Pharmaceutics Jul 2023Powder flow is a critical attribute of pharmaceutical blends to ensure tablet weight uniformity and production of tablets with consistent and reproducible properties....
Powder flow is a critical attribute of pharmaceutical blends to ensure tablet weight uniformity and production of tablets with consistent and reproducible properties. This study aims at characterizing different powder blends with a number of different rheologic techniques, in order to understand how particles' attributes and interaction between components within the formulation generate different responses when analysed by different rheological tests. Furthermore, this study intends on reducing the number of tests in early development phases, by selecting the ones that provide the best information about the flowability attributes of the pharmaceutical blends. This work considered two cohesive powders - spray-dried hydroxypropyl cellulose (SD HPMC) and micronized indomethacin (IND) - formulated with other four commonly used excipients [(lactose monohydrated (LAC), microcrystalline cellulose (MCC), magnesium stearate (MgSt) and colloidal silica (CS)]. The experimental results showed that powder flowability may be affected by materials particles' size, bulk density, morphology, and interactions with lubricant. In detail, parameters, such as angle of repose (AoR), compressibility percentage (CPS), and flow function coefficient (ff) have shown to be highly affected by the particle size of the materials present in the blends. On the other hand, the Specific Energy (SE) and the effective angle of internal friction (φe) showed to be more related with particle morphology and materials interaction with the lubricant. Since both ff and φe parameters are generated from the yield locus test, data suggest that a number of different powder flow features may be understood only by applying this test, avoiding redundant powder flow characterization, as well as extensive time and material spent in early development formulation stages.
Topics: Powders; Excipients; Rheology; Tablets; Particle Size; Lubricants
PubMed: 37279868
DOI: 10.1016/j.ijpharm.2023.123107 -
Macromolecular Bioscience Dec 2023Particle-mediated self-assembly, such as nanocomposites, microstructure formation in materials, and core-shell coating of biological particles, offers precise control...
Particle-mediated self-assembly, such as nanocomposites, microstructure formation in materials, and core-shell coating of biological particles, offers precise control over the properties of biological materials for applications in drug delivery, tissue engineering, and biosensing. The assembly of similar-sized calcium alginate (CAG) and polystyrene sub-micron particles is studied in an aqueous sodium nitrate solution as a model for particle-mediated self-assembly of biological and synthetic mixed particle species. The objective is to reinforce biological matrices by incorporating synthetic particles to form hybrid particulate networks with tailored properties. By varying the ionic strength of the suspension, the authors alter the energy barriers for particle attachment to each other and to a glass substrate that result from colloidal surface forces. The particles do not show monotonic adsorption trend to glass with ionic strength. Hence, apart from DLVO theory-van der Waals and electrostatic interactions-the authors further consider solvation and bridging interactions in the analysis of the particulate adsorption-coagulation system. CAG particles, which support lower energy barriers to attachment relative to their counterpart polystyrene particles, accumulate as dense aggregates on the glass substrate. Polystyrene particles adsorb simultaneously as detached particles. At high electrolyte concentrations, where electrostatic repulsion is largely screened, the mixture of particles covers most of the glass substrate; the CAG particles form a continuous network throughout the glass substrate with pockets of polystyrene particles. The particulate structure is correlated with the adjustable energy barriers for particle attachment in the suspension.
Topics: Polystyrenes; Alginates; Colloids; Adsorption; Osmolar Concentration; Particle Size
PubMed: 37551162
DOI: 10.1002/mabi.202300219 -
The AAPS Journal Oct 2023Nanoparticles can encapsulate a range of therapeutics, from small molecule drugs to sensitive biologics, to significantly improve their biodistribution and biostability.... (Review)
Review
Nanoparticles can encapsulate a range of therapeutics, from small molecule drugs to sensitive biologics, to significantly improve their biodistribution and biostability. Whilst the regulatory approval of several of these nanoformulations has proven their translatability, there remain several hurdles to the translation of future nanoformulations, leading to a high rate of candidate nanoformulations failing during the drug development process. One barrier is that the difficulty in tightly controlling nanoscale particle synthesis leads to particle-to-particle heterogeneity, which hinders manufacturing and quality control, and regulatory quality checks. To understand and mitigate this heterogeneity requires advancements in nanoformulation characterisation beyond traditional bulk methods to more precise, single particle techniques. In this review, we compare commercially available single particle techniques, with a particular focus on single particle Raman spectroscopy, to provide a guide to adoption of these methods into development workflows, to ultimately reduce barriers to the translation of future nanoformulations.
Topics: Tissue Distribution; Nanoparticles; Pharmaceutical Preparations; Particle Size
PubMed: 37783923
DOI: 10.1208/s12248-023-00855-w -
Food Chemistry Aug 2023The influence of sucrose source and particle size was investigated in relation to the volatile and aromatic properties of sponge cakes. Six sponge cake formulations were...
The influence of sucrose source and particle size was investigated in relation to the volatile and aromatic properties of sponge cakes. Six sponge cake formulations were studied using two sucrose sources (sugarbeet and sugarcane), at two particle sizes (large and small) with controls. Volatiles profiles and odour active compounds were identified by gas chromatography mass spectrometry and olfactometry. Sixty two volatile compounds were identified, incorporating twenty five odour active compounds/co-eluting compounds, with 5 odours perceived without any corresponding volatile. Particle size had the greatest impact on volatile abundance, with particle size especially influencing pyrazine abundance. Five odour active volatiles (methional, furfural, 2,3-dimethylpyrazine, heptanal and (E)-2-octenal) contributed most to the aroma of these sponge cakes. Small particle size particularly from sugarbeet yielded higher levels of some Maillard and caramelisation reaction compounds, such as furfural (spicy/ bready), where larger particle size supressed volatile abundance in comparison to the control.
Topics: Odorants; Particle Size; Furaldehyde; Volatile Organic Compounds; Gas Chromatography-Mass Spectrometry; Olfactometry; Vegetables
PubMed: 36958203
DOI: 10.1016/j.foodchem.2023.135860 -
Molecular Pharmaceutics Jan 2024The authors present a steady-state-, particle-size-, and dose-dependent dissolution-permeation model that describes particle dissolution within the concentration...
The authors present a steady-state-, particle-size-, and dose-dependent dissolution-permeation model that describes particle dissolution within the concentration boundary layer (CBL) adjacent to a semipermeable surface. It is critical to understand how particle size and dose affect the behavior of dissolving particles in the presence of a CBL adjacent to a semipermeable surface both and . Control of particle size is ubiquitous in the pharmaceutical industry; however, traditional pharmaceutical assumptions of particle dissolution typically ignore particle dissolution within the length scale of the CBL. The CBL does not physically prevent particles from traveling to the semipermeable surface (mucus, epithelial barrier, synthetic membrane, etc.), and particle dissolution can occur within the CBL thickness (δ) if the particle is sufficiently small (∼ ≤ δ). The total flux (the time rate transport of molecules across the membrane surface per unit area) was chosen as a surrogate parameter for measuring the additional mass generated by particles dissolving within the donor CBL. Mass transfer experiments aimed to measure the total flux of drug using an ultrathin large-area membrane diffusion cell described by Sinko et al. with a silicone-based membrane ( 2020, 17, (7) 2319-2328, DOI: 10.1021/acs.molpharmaceut.0c00040). Suspensions of ibuprofen, a model weak-acid drug, with three different particle-size distributions with average particle diameters of 6.6, 37.4, and 240 μm at multiple doses corresponding to a range of suspension concentrations with dimensionless dose numbers of 2.94, 14.7, 147, and 588 were used to test the model. Experimentally measured total flux across the semipermeable membrane/CBL region agreed with the predictions from the proposed model, and at a range of relatively low suspension concentrations, dependent on the average particle size, there was a measurable effect on the flux due to the difference in δ that formed at the membrane surface. Additionally, the dose-dependent total flux across the membrane was up to 10% higher than the flux predicted by the standard Higuchi-Hiestand dissolution model where the effects of confinement were ignored as described by Wang et al. ( 2012, 9 (5), 1052-1066, DOI: 10.1021/mp2002818).
Topics: Particle Size; Solubility; Diffusion
PubMed: 38115627
DOI: 10.1021/acs.molpharmaceut.3c00761 -
The Science of the Total Environment May 2024The global concern regarding the health risk associated with airborne microorganisms has prompted research in this field. However, there is a lack of systematic...
The global concern regarding the health risk associated with airborne microorganisms has prompted research in this field. However, there is a lack of systematic investigation into the particle-size distribution of airborne bacterial and fungal communities associated with seasons, which determines where they are deposited in the human respiratory tract. To address this gap, we conducted a study in Nanchang, located in central China, where we collected both coarse and fine particles during summer and winter seasons. The results demonstrated that microbial community exhibited obvious seasonal and particle-size variations except bacterial community in fine particles. Certain taxa (e.g., Bacteroidales, Ktedonobacterales, Capnodiales) displayed either seasonal and/or particle-size preferences. Furthermore, airborne microorganisms in coarse particles were more sensitive to season and particle size compared to those in fine particles, with fungal community being more susceptible than bacterial community. The susceptibility can be attributed to their high vulnerability to air pollutants and meteorological conditions, primarily PM and PM. Additionally, a greater relative abundance of pathogenic fungi was observed in fine particles, even though microbial diversity in coarse particles was noticeably higher than that in fine particles. Furthermore, some predominant pathogens such as Alternaria, Nigrospora, and Escherichia-Shigella not only had particle size and/or seasonal preferences, but also were strongly correlated with environmental factors. This study advances our understanding of atmospheric pathogenic microorganisms and highlights the fungal health threat.
Topics: Humans; Particle Size; Particulate Matter; Seasons; Mycobiome; Air Microbiology; Environmental Monitoring; Air Pollutants; Bacteria; Alternaria
PubMed: 38492598
DOI: 10.1016/j.scitotenv.2024.171584