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Environmental Pollution (Barking, Essex... Dec 2023Indoor airborne ultrafine particles (UFPs) are mainly originated from occupant activities, such as candle burning and cooking. Elevated exposure to UFPs has been found...
Indoor airborne ultrafine particles (UFPs) are mainly originated from occupant activities, such as candle burning and cooking. Elevated exposure to UFPs has been found to increase oxidative stress and cause DNA damage. UFPs originating from indoor sources undergo dynamic aerosol transformation mechanisms. This study investigates the dynamics of UFPs following episodic indoor releases of the six distinct emission sources: 1) candle, 2) gas stove, 3) clothes dryer, 4) tea & toast, 5) broiled fish, and 6) incense. Based on the analytical model of aerosol dynamic processes, this study reports size-resolved source emission rates along with relative contributions of coagulation, deposition, and ventilation to the particle size distribution dynamics. The study findings indicate a significant variation in the geometric mean diameter (GMD) and size-resolved number concentration over time for the sources that emit a substantial amount of UFPs smaller than 10 nm. As the emission progresses, the UFP number concentrations increase in a log-normal distribution, while the GMD shows a tendency to increase over time. The observed result suggests that coagulation can have a considerable impact on UFP number concentration and size, even during the indoor UFP emission. The estimated emission rates of the six indoor sources appear to follow a log-normal distribution while the emission rate ranges from 10 min to 10 min. The indoor UFP concentration and size distribution dynamics are substantially affected by the interplay of the three aerosol loss mechanisms that compete with each other, and this impact varies according to the source type and the indoor environmental conditions. Ultimately, using the aerosol transformation mechanisms examined in this study, researchers can refine exposure assessment for epidemiological studies on indoor ultrafine particles.
Topics: Particulate Matter; Air Pollutants; Particle Size; Environmental Monitoring; Air Pollution, Indoor; Aerosols
PubMed: 37821040
DOI: 10.1016/j.envpol.2023.122680 -
Journal of Pharmaceutical Sciences Sep 2023Despite significant research progress in substantiating the therapeutic merits of nanomedicines and the emergence of sophisticated nanotechnologies, the translation of... (Review)
Review
Despite significant research progress in substantiating the therapeutic merits of nanomedicines and the emergence of sophisticated nanotechnologies, the translation of this knowledge into new therapeutic modalities has been sluggish, indicating the need for a more comprehensive understanding of how the unique physicochemical properties of nanoparticles affect their clinical applications. Particle size is a critical quality attribute that impacts the bio-fate of nanoparticles, yet precise knowledge of its effect remains elusive with discrepancies among literature reports. This review aims to address this scientific knowledge gap from a drug development perspective by highlighting potential inadequacies during the evaluation of particle size effects. We begin with a discussion on the major issues in particle size characterization along with the corresponding remedies. The influence of confounding factors on biological effects of particle size, including colloidal stability, polydispersity, and in vitro drug release, are addressed for establishing stronger in vitro-in vivo correlation. Particle size design and tailoring approaches for successful nanoparticulate drug delivery beyond parenteral administration are also illustrated. We believe a holistic understanding of the effect of particle size on bio-fate, combined with consistent nanoparticle manufacturing platforms and tailored characterization techniques, would expedite the translation of nanomedicines into clinical practice.
Topics: Nanomedicine; Particle Size; Translational Research, Biomedical; Drug Delivery Systems; Nanotechnology; Nanoparticles
PubMed: 37453526
DOI: 10.1016/j.xphs.2023.07.002 -
Toxins Jul 2023Sample homogeneity dictates whether analyzing a test portion of an entire sample can provide representative information about incurred mycotoxins. In this study, we...
Sample homogeneity dictates whether analyzing a test portion of an entire sample can provide representative information about incurred mycotoxins. In this study, we evaluated particle-size-distribution-based homogeneity of laboratory mycotoxin samples using laser diffraction particle size analysis and International Organization for Standardization (ISO) Guide 35: 2017. Incurred whole corn, compound feed, peanut butter, and wheat flour (500 g each) were comminuted using wet, cryogenic, or dry milling. We used a sample dividing (riffling) device to obtain representative subsamples (25 g each) and developed a laser diffraction particle size analysis procedure by optimizing key parameters such as the refractive index, absorption, and stirring rate. The homogeneity of the particle size distribution within laboratory subsamples was characterized using the optimized laser diffraction procedure. An assessment of homogeneity was also performed for individual mycotoxins in each incurred matrix sample following the procedure described in ISO Guide 35. The concentrations of the incurred mycotoxins were determined using liquid chromatography-mass spectrometry (LC-MS). Within- and between-subsample variances of incurred aflatoxin B1 in peanut butter; deoxynivalenol in corn, compound feed, and wheat flour; and fumonisins in compound feed corroborated that when the particle size measurements were less than 850 µm, mycotoxins concentrations were consistent across independent test portions, which was confirmed using an analysis of variance (F-test). This study highlights the benefits of laser diffraction particle size analysis and suggests its use as a test procedure to evaluate homogeneity in new sample commodities.
Topics: Mycotoxins; Particle Size; Flour; Food Contamination; Triticum; Zea mays
PubMed: 37505719
DOI: 10.3390/toxins15070450 -
Environment International May 2024Ambient air ultrafine particles (UFP, particles with a diameter <100 nm) have gained significant attention in World Health Organization (WHO) air quality guidelines and... (Review)
Review
Ambient air ultrafine particles (UFP, particles with a diameter <100 nm) have gained significant attention in World Health Organization (WHO) air quality guidelines and European legislation. This review explores UFP concentrations and particle number size distributions (PNC-PNSD) in various transportation hotspots, including road traffic, airports, harbors, trains, and urban commuting modes (walking, cycling, bus, tram, and subway). The results highlight the lack of information on personal exposure at harbors and railway stations, inside airplanes and trains, and during various other commuting modes. The different lower particle size limits of the reviewed measurements complicate direct comparisons between them. Emphasizing the use of instruments with detection limits ≤10 nm, this review underscores the necessity of following standardized UFP measurement protocols. Road traffic sites are shown to exhibit the highest PNC within cities, with PNC and PNSD in commuting modes driven by the proximity to road traffic and weather conditions. In closed environments, such as cars, buses, and trams, increased external air infiltration for ventilation correlates with elevated PNC and a shift in PNSD toward smaller diameters. Airports exhibit particularly elevated PNCs near runways, raising potential concerns about occupational exposure. Recommendations from this study include maintaining a substantial distance between road traffic and other commuting modes, integrating air filtration into ventilation systems, implementing low-emission zones, and advocating for a general reduction in road traffic to minimize daily UFP exposure. Our findings provide important insights for policy assessments and underscore the need for additional research to address current knowledge gaps.
Topics: Particulate Matter; Particle Size; Transportation; Environmental Monitoring; Air Pollutants; Vehicle Emissions; Air Pollution; Humans; Cities
PubMed: 38678934
DOI: 10.1016/j.envint.2024.108696 -
Environmental Science & Technology Sep 2023Environmental DNA (eDNA) in aquatic systems is a complex mixture that includes dissolved DNA, intracellular DNA, and particle-adsorbed DNA. Information about the various...
Environmental DNA (eDNA) in aquatic systems is a complex mixture that includes dissolved DNA, intracellular DNA, and particle-adsorbed DNA. Information about the various components of eDNA and their relative proportions could be used to discern target organism abundance and location. However, a limited knowledge of eDNA adsorption dynamics and interactions with other materials hinders these applications. To address this gap, we used recirculating stream mesocosms to investigate the impact of suspended materials (fine particulate organic matter, plankton, clay, and titanium dioxide) on the eDNA concentration and particle size distribution (PSD) from two fish species in flowing water. Our findings revealed that eDNA rapidly adsorbs to other materials in the water column, affecting its concentration and PSD. Nonetheless, only particulate organic matter affected eDNA removal rate after 30 h. Moreover, we observed that the removal of larger eDNA components (≥10 μm) was more strongly influenced by physical processes, whereas the removal of smaller eDNA components was driven by biological degradation. This disparity in removal mechanisms between larger and smaller eDNA components could explain changes in eDNA composition over time and space, which have implications for modeling the spatial distribution and abundance of target species and optimizing eDNA detection in high turbidity systems.
Topics: Animals; DNA, Environmental; Particle Size; Physical Phenomena; Adsorption; Particulate Matter; Water
PubMed: 37610829
DOI: 10.1021/acs.est.3c02638 -
Food Research International (Ottawa,... Nov 2023Chickpeas are an agriculturally-important legume that are an excellent source of protein, fiber, and minerals. Developing chickpea-based snacks could provide consumers...
Chickpeas are an agriculturally-important legume that are an excellent source of protein, fiber, and minerals. Developing chickpea-based snacks could provide consumers with snack products rich in protein and other nutrients. In this study, chickpea puree (high moisture content) and cracker (low moisture content) were each produced with large (7 mm sieve; coarse) or small (2 mm sieve; fine) particle size to investigate the impact of initial particle size and moisture content on particle breakdown, starch hydrolysis, and protein hydrolysis during in vitro digestion. All treatments underwent static in vitro oral digestion, dynamic gastric digestion in the Human Gastric Simulator (HGS), and static in vitro small intestinal digestion. The emptying rate from the HGS was significantly (p < 0.05) higher for fine puree compared to the other treatments, due to higher saturation ratio and smaller initial particle size. The reducing sugars and free amino groups released (representing starch and protein hydrolysis, respectively) from fine puree were higher than coarse puree, and fine cracker was higher than coarse cracker due to the influence of initial particle size. For example, after 360 min total in vitro digestion, the starch hydrolysis of the fine cracker (48.1 ± 3.2%) was significantly higher than (p < 0.05) the coarse cracker (36.3 ± 5.8%). Overall, crackers had higher protein and starch hydrolysis compared to puree in the liquid phase during digestion. The study showed that both the smaller initial particle size and drying significantly (p < 0.05) increased the particle size reduction during gastric digestion and starch and protein digestibility in chickpea-based snacks.
Topics: Humans; Starch; Cicer; Snacks; Particle Size; Water; Digestion
PubMed: 37803531
DOI: 10.1016/j.foodres.2023.113201 -
Biology Open Sep 2023The webbed foot structure of mallards (Anas platyrhynchos) exhibits effective anti-subsidence properties when walking on soft ground. To investigate the effects of...
The webbed foot structure of mallards (Anas platyrhynchos) exhibits effective anti-subsidence properties when walking on soft ground. To investigate the effects of quartz sand particle size and thickness on joint angles and the movement patterns of webbed feet, we created a testing substrate with quartz sand and utilized high-speed cameras and kinematic analysis tools for data acquisition. Mallards mainly adjusted the tarsometatarso-phalangeal joint (TMTPJ) during touch-down and lift-off stages in response to increasing particle size or enhanced ground roughness. Conversely, adjustments to the intertarsal joint (ITJ) predominantly took place during mid-stance. Conversely, mallards predominantly adjusted the ITJ during touch-down and lift-off when coping with increased quartz sand thickness, with TMTPJ adjustments mainly occurring at touch-down. As quartz sand particle size increased, the TMTPJ angle increased, the ITJ angle decreased, toe closure advanced, and the duty factor decreased throughout the entire stride cycle. In contrast, increasing quartz sand thickness led to more delayed TMTPJ adjustments, slower webbed foot closure, and an increased duty factor throughout the stride cycle. Mallards modify their leg posture to notably decrease the touch-down foot angle upon encountering sandy terrain. This action subsequently forms a depression beneath their feet, contributing to sand consolidation and limiting flow. During the stance phase, the mallard's weight is distributed across the webbed foot, generating minimal pressure and preventing significant subsidence while walking on sandy ground.
Topics: Quartz; Sand; Biomechanical Phenomena; Particle Size; Lower Extremity
PubMed: 37605960
DOI: 10.1242/bio.060012 -
Analytical Chemistry Jul 2023Acoustophoresis has become a powerful tool to separate microparticles and cells, based on their material and biophysical properties, and is gaining popularity in...
Acoustophoresis has become a powerful tool to separate microparticles and cells, based on their material and biophysical properties, and is gaining popularity in clinical and biomedical research. One major application of acoustophoresis is to measure the compressibility of cells and small organisms, which is related to their contents. The cell compressibility can be extracted from the acoustic mobility, which is the main output of acoustic migration experiments, if the material properties and sizes of reference particles, the size of the cells, and the surrounding medium are known. Accurate methods to measure and calibrate the acoustic energy density in acoustophoresis systems are therefore critical. In this Perspective, polystyrene microparticles have become the most commonly used reference particles in acoustophoresis, due to their similar biophysical properties to cells. We utilized a two-step focusing method to measure the relative acoustic mobility of polystyrene beads of various sizes and colors and present a quantitative analysis of the variation in acousto-mechanical properties of polystyrene microparticles, showing a large spread in their material properties. A variation of more than 25% between different particle types was found. Thus, care is required when relying on polystyrene particles as a reference when characterizing acoustofluidics systems or acousto-mechanical properties of cells.
Topics: Polystyrenes; Microfluidic Analytical Techniques; Particle Size; Acoustics; Cell-Derived Microparticles
PubMed: 37363950
DOI: 10.1021/acs.analchem.3c01156 -
The Science of the Total Environment Sep 2023Bioaccessible fractions of particle-bound hydrophobic organic compounds (HOCs) are critical to evaluating human inhalation exposure risk. However, the key factors for...
Bioaccessible fractions of particle-bound hydrophobic organic compounds (HOCs) are critical to evaluating human inhalation exposure risk. However, the key factors for controlling the release of HOCs into the lung fluid are not adequately examined. To address this issue, eight particle size fractions (0.056-18 μm) from different particle emission sources (barbecue and smoking) were collected and incubated with an in vitro method for determining inhalation bioaccessibilities of polycyclic aromatic hydrocarbons (PAHs). The bioaccessible fractions of particle-bound PAHs were 35-65% for smoke-type charcoal, 24-62% for smokeless-type charcoal, and 44-96% for cigarette. The size distributions of bioaccessible fractions of 3-4 ring PAHs were symmetric with the patterns of their masses, characterized as a unimodal distribution with both the trough and peak at 0.56-1.0 μm. Analysis from machine learning showed that chemical hydrophobicity appeared to be the most significant factor affecting inhalation bioaccessibility of PAHs, followed by organic carbon and elemental carbon contents. Particle size seemed to have little effect on the bioaccessibility of PAHs. A compositional analysis of human inhalation exposure risk from total concentration, deposition concentration, and bioaccessible deposition concentration in alveolar region showed a shift in the key particle size from 0.56-1.0 μm to 1.0-1.8 μm and an increasing in the contributions of 2-3 ring PAHs to risk for cigarette due to the high bioaccessible fractions. These results suggested the significance of particle deposition efficiency and bioaccessible fractions of HOCs in risk assessment.
Topics: Humans; Particle Size; Air Pollutants; Charcoal; Carbon; Polycyclic Aromatic Hydrocarbons; Organic Chemicals; Environmental Monitoring; Particulate Matter
PubMed: 37201831
DOI: 10.1016/j.scitotenv.2023.164225 -
Environmental Pollution (Barking, Essex... Oct 2023Suspended sediment (SPS) is an important environmental factor in eutrophic lakes, where they may play a significant role in the microbial nitrogen cycle and thus affect...
Suspended sediment (SPS) is an important environmental factor in eutrophic lakes, where they may play a significant role in the microbial nitrogen cycle and thus affect the NO source and sink function. This study investigated the correlation and corresponding microbial mechanisms between NO emission fluxes and SPS particle sizes. NO emission characteristics were investigated in four parallel operated lab-scale microcosmic systems, in which different sizes of SPS particles were inoculated (i.e., <75, 75-150, 150-300, and >300 μm). The results show that, NO emission fluxes in the eutrophic lakes were exponentially correlated with the lake trophic level index (TLI) (R = 0.94, p < 0.01) and the specific surface area of the SPS (R = 0.38, p < 0.05). In the microcosmic systems, SPS with 75-150 μm particles had the highest NO emission rate of 5.94 ± 0.007 μg N/L/d, which was 2.6 times that of the <75 μm particle size system. The microcosmic system with particle size >300 μm had the highest NO reduction rate (Vmax) of 6.776 μmol/L/h, which was 16-50 times that of the other three groups. Larger particle size SPS have a smaller specific surface area, which could affect the microenvironment on SPS surface and thus affect the microbe functions. The microbial community structure results indicated that the dominant microorganisms on the SPS surface were denitrifying bacteria. The maximum (nirS + nirK)/nosZ ratio was 30.2 for the 75-150 μm system, which was nearly 2 times higher than the other systems. The >300 μm system had the highest nosZ abundance, indicating a strong ability to reduce NO. The co-occurrence networks analysis indicated that the cooperation and competition among nitrifiers and denitrifiers determined NO emissions. These results provide fundamental insights into the influence of SPS size on NO emissions in eutrophic lakes.
Topics: Lakes; Nitrous Oxide; Particle Size; Denitrification; Geologic Sediments
PubMed: 37442329
DOI: 10.1016/j.envpol.2023.122180