Increase In Particle Size Research Articles

Quantitative characterization of multiple cracks and permeability in coral sand engineered cementitious composites based on micro-computed tomography

Seawater–coral sand engineered cementitious composites (SCECCs) offer an effective solution for marine construction by utilizing local resources, thereby reducing costs and improving efficiency. This study examines the crack characteristics and permeability of SCECCs after loading, which are less understood aspects of these materials. Uniaxial tension tests were performed on SCECC specimens with varying particle sizes and aggregate types. High-resolution micro-computed tomography (micro-CT) and 3D visualization techniques were employed to analyze the formation and distribution of cracks as well as the permeability properties of the material. The findings indicate that as the maximum particle size increases, the volume fraction of cracks decreases. The crack distribution density initially rises and then falls with increasing particle size, while the spacing of cracks show the opposite trend. Specimens with 0.60mm aggregates demonstrated the most uniform and favorable crack distribution, outperforming similar freshwater–quartz sand ECC mixtures. Key factors influencing the permeability of cracked SCECCs include the pore throat parameters, volume ratios of pores and pore throats across different radii, and the spatial distribution of these structures. The SCECC’s ability to disperse deformation among numerous small cracks significantly enhances its impermeability, making it a highly suitable material for marine engineering applications.

Experimental study on the concentration fluctuation of dust particles with different sizes during a dust storm

The particle size distribution (PSD) and concentration fluctuation were analyzed during different stages of a dust event. Our results show that dust smaller than 0.5 μm were dominant during the development stage; dust less than 0.5 μm decreased and dust from 0.5 μm to 10 μm increased in the high and low concentration stage; dust from 0.5 μm to 10 μm decreased and dust less than 0.5 μm increased in the dissipation stage. PSD of the first and fourth stages shows the unimodal distribution, but that of the other stages shows the distribution of 4 peaks. For large scale fluctuation with a period larger than 300 s, the concentration fluctuation of particles with size less than 0.4 μm and size larger than 0.4 μm has a high correlation. For small scale fluctuation with period less than 300 s, some particle size segments have high correlation at different stages, while some particle size segments have poor correlation at different stages. At the same stage, the size of the benchmark particle that is highly correlated in different particle size segments fluctuates with increasing particle size. In addition, the concentration fluctuation in 0.01276 Hz ∼ 0.02084 Hz and 0.00285 Hz ∼ 0.01096 Hz has significant contributions.

Nano spray-dried particles of in-situ crosslinked alginate and their toxicological characterisation

The feasibility and technical capacity for producing crosslinked sub-micron gels with a nano spray-dryer were studied with variable pH systems incorporating alginate, pectin, and pullulan. The obtained powders were characterized for their morphology, particle size distribution, and their toxicological safety profile using genotoxicity and cytotoxicity assays. Additionally, quercetin was added to the encapsulation system to study the potential of the system to encapsulate this material. The produced powders exhibited morphologies and particle size distributions characteristic for nano spray-drying. The addition of pullulan and pectin to the feed solutions resulted in a particle size increase, with crosslinked alginate particles having a mean value of 1.43 μm, while particles with added pectin and pullulan had a mean particle size of 1.70 and 1.75 μm, respectively. The inclusion of quercetin proved to be problematic with this encapsulation system. Extremely high degradation rates and extremely low encapsulation efficiencies were observed due to the alkaline pH (~10) of the system that is needed to keep the feed dispersion in a liquid state and prevent premature crosslinking of the alginate. Although pectin and pullulan provided some protection for quercetin in the alkaline dispersion, the absolute quercetin content in the final product remained very low, with a maximum achieved encapsulation efficiency of 2.06 %. The safety profile of most produced powders was favourable, as they did not exhibit any significant cytotoxic and genotoxic activity in the HepG2 cell line, except in the case of Alginate/Pullulan which showed a 43 % decrease in cell viability at 500 μg/ml. Samples where quercetin was added did not show any increased toxicological effect.

Performance and mechanism of bio-oil "chain-pyrolytic" crumb rubber and SBS composite modified asphalt

To enhance the high-temperature performance of bio-oil degraded crumb rubber (CR) modified asphalt, a "chain-pyrolysis" treatment of CR was conducted using waste frying oil. This involved adding the CR in batches to the high-temperature waste oil to increase the CR-to-oil ratio, and control the degree of CR degradation. The effects of pyrolysis batch on the physicochemical properties of CR were evaluated through solubility, particle size analysis, thermal analysis, and scanning electron microscope. The performance and mechanism of "chain-pyrolytic" crumb rubber/Styrene-Butadiene-Styrene composite modified asphalt (PCR/SBSCMA) were investigated using conventional performance tests, rheological tests, Fourier transform infrared spectroscopy, fluorescence microscopy, and atomic force microscope. Results show that during the "chain-pyrolysis" process of CR, the sol content decreases, reaching a plateau after 3 batches and decreasing after 7 batches, indicating a decline in degradation degree. The particle size increases, whereas the rubber hydrocarbon content marginally rises, and the surface texture complexity diminishes with each batch. With an escalation in pyrolysis batch of CR, the penetration of the PCR/SBSCMA hits a minimum, the ductility gradually diminishes and the softening point slowly increases after 3 batches. The phase angle and non-recoverable creep compliance decrease, while the complex shear modulus and recovery rate enhance, significantly boosting the elasticity of the modified asphalt. The preparation of PCR and modification of PCR/SBSCMA contain the cleavage of sulfur bonds, the formation of oxygen functional groups, and the CR swelling. The uniform dispersion of polymer phases, presence of fine carbon black, and establishment of a stable colloidal system contribute the high-temperature mechanical properties and stability of the PCR/SBSCMA. The reduction of light components in the PCR/SBSCMA caused by swollen CR results in diminished surface roughness, disappeared "bee-like" structure, and improved homogeneity, which is conducive to low-temperature ductility. Overall, the PCR/SBS composite modification method promotes the high-quality and sustainable development of the utilization of waste tires and biomass in asphalt pavement.

Multi-stage evolution characteristics and particle size effect of sandstone granules subjected to cyclic loads

Broken granules of different sizes and poor bearing capacities produced by repeated mining of coal seams contribute to natural disasters, such as rock strata movement. In this study, mechanical tests were performed on broken sandstone granules to explore their compaction and recrushing characteristics under repeated mining. The change characteristics of the relevant mechanical parameters of sandstone granules with different particle sizes and changes in energy density were examined, and compaction and recrushing mechanisms of sandstone granules under cyclic loading were identified. The results show that an increase in the initial particle size of sandstone granules has a significant effect on the increase in the strain under load. The cumulative dissipation energy corresponding to final crushing was greater for granules with larger initial sizes. The particle size of sandstone was found to be proportional to the fractal dimension after compaction and crushing. The probability of granular particles with larger initial particle sizes being broken into smaller particles is greater, resulting in the porosity attenuating most rapidly during the stress loading process of granular particles under repeated mining. Therefore, the degree of sample breakage was relatively severe. Particles were rearranged after compaction and crushing. Repeated mining results in dynamic evolution of the pore compaction, deformation, and fractur of the rock mass, as well as stable recombination. The study results provide important theoretical support for understanding of the movement mechanism of rock strata in the goaf under repeated mining.

Colloidal state-based studies on the chloride salts of magnesium- and calcium-induced coagulation of soymilks.

Chloride salts (MgCl2 and occasionally CaCl2) coagulation of the heated soymilks is the key step in manufacturing traditional tofu. In this study, colloidal state diagrams were constructed first, and then the effects of processing parameters, including coagulant concentration, preheating intensity, protein concentration, and coagulation temperature as well as the intrinsic properties (phytate concentration) on the microstructure, protein coagulability, and water holding capacity (WHC) were investigated to gain an overall framework understanding of the Mg2+ and Ca2+ coagulated soymilk process. As the variables changed, the coagulated soymilks displayed one of the following states: colloidal suspension, flocs, weak gel, and strong gel. The microstructures of the coagulated systems also changed to different features with the variation in processing parameters and phytate concentrations. Several interesting results were obtained. It was found that the transformations from colloidal suspension to gel state were usually corresponding to the increase of particle size, the decrease of porosity, and a sharp increase in protein coagulability. The colloidal states of Mg2+ and Ca2+ coagulated soymilks were usually different, but their microstructures were similar. With the increase of protein concentration, the protein coagulability decreased but the WHC was enhanced. The presence of high phytate contents led to form small protein agglomerates, which resulted in worse protein coagulation and WHC. It is expected that this study will deepen the understanding of chloride salts coagulation process.

Effect of recycled concrete powder on the rheological properties of cement paste: New findings

Recycled concrete powder (RCP) influences cement paste's rheology, but the mechanisms remain unclear. This paper intends to fill this gap by employing a new method for measuring water absorption, the minimum water requirement method, an organic carbon analyser, and a laser particle size analyser. The cementitious material's water absorption (W), packing density (φm), water reducer adsorption (Qad), and particle size distribution are determined. Results show that, as the RCP's content increases from 0 % to 25 %, the cementitious material's W, φm, Qad, volume fraction, and average particle size increase by 21.7 %, 0.9 %, 26.2 %, 1.4 %, and 30.6 %, respectively. Consequently, the particle's surface covered by the water reducer (θ) and distance (H) decrease by 26.5 % and 32.6 %, respectively, resulting in an increase in the paste's yield stress (τ0) and plastic viscosity (ηpl) by 1946.6 % and 45.3 %, respectively. Based on an existing yield stress model, RCP affecting τ0 can be attributed to changes in the particle system's colloidal and contact interactions. A decrease in H increases colloidal interactions. Conversely, an increase in φm and a decrease in fine particle content reduce contact interactions. Colloidal interactions are more significant, thus τ0 increases. Based on the functional expression for the ηpl developed here, RCP affecting ηpl can be attributed to changes in hydrodynamic interactions and contact interactions. A decrease in H increases hydrodynamic interactions. An increase in φm combined with a decrease in fine particle content decrease contact interactions. Additionally, an increase in Qad reduces pore solution's viscosity. Hydrodynamic interactions are more significant, thus increasing ηpl.

High-temperature shrinkage compensation of cesium-based geopolymer: Synergistic effects of kyanite decomposition, ceramization and phase transformation

Cesium-based geopolymers and their ceramization product, pollucite, exhibit excellent heat resistance and considerable potential as engineering materials for high-temperature environments. However, the substantial shrinkage of cesium-based geopolymer during the ceramization process hinders its wide application. In this study, cesium-based geopolymer composites were prepared and evaluated on their shrinkage compensation, with the addition of reinforcing phases of kyanite or corundum. Compared with the sample with the addition of corundum, the linear shrinkage of the sample with the addition of kyanite after heat treatment at 1400 °C was reduced from 15.30 % to 6.28 %, showing a decrease by 54.89 % in linear shrinkage. There was no reaction between kyanite and geopolymer at room temperature, and the ceramization process of the cesium-based geopolymer was not altered either. The decomposition of kyanite at 1200–1400 °C during heat treatment produced mullite and silica, which expanded the volume by 18 %. This compensated for the shrinkage that occurred during the subsequent processes of ceramization and sintering of geopolymer. Mullite and silica further reacted with CsAlSiO4-ANA (having the same cubic ANA type zeolite framework as pollucite) to form corundum and pollucite (CsAlSi2O6) at 1300–1400 °C, during which the average size of pollucite grains increased from 1.82 μm to 4.34 μm, with an increase of 238.46 %. The reaction in this stage prevented the volatilization of cesium in the high temperature, and the increase of pollucite particle size reduced the shrinkage and porosity. This study cast the light on the design and preparation of low-shrinkage, ceramizable, geopolymer composites by synergistic effects of kyanite decomposition, ceramization and high-temperature phase transformation.

Experimental Investigation on the Permeability and Fine Particle Migration of Debris-Flow Deposits with Discontinuous Gradation: Implications for the Sustainable Development of Debris-Flow Fans in Jiangjia Ravine, China

The particle size distribution (PSD) is a crucial parameter used to characterize the material composition of debris-flow deposits which determines their hydraulic permeability, affecting the mobility of debris flows and, hence, the sustainable development of debris-flow fans. Three types of graded bedding structures—normal, reverse, and mixed graded bedding structures—are characterized by discontinuous gradation within a specific deposit thickness. A series of permeability tests were conducted to study the effects of bed sediment composition, particularly coarse grain sizes and fine particle contents, on the permeability and migration of fine particles in discontinuous debris-flow deposits. An increase in fine particles within the discontinuously graded bed sediment led to a power-law decrease in the average permeability coefficient. With fine particle contents of 10% and 15% in the bed sediments, the final permeability coefficient consistently exceeded the initial value. However, this trend reversed when the fine particle contents were increased to 20%, 25%, and 30%. Lower fine particle contents indicated enhanced permeability efficiency due to more interconnected voids within the coarse particle skeleton. Conversely, an increase in fine particle content reduced the permeability efficiency, as fine particles tended to aggregate at the lower section of the seepage channel. An increase in coarse particle size decreased the formation of flow channels at the coarse–fine particle interface, causing fine particles to move slowly along adjacent or clustered slow flow channels formed by fine particles, resulting in decreased permeability efficiency. Three formulae are proposed to calculate the permeability coefficients of discontinuously graded bed sediments, which may aid in understanding the initiation mechanism of channel deposits. Based on experimental studies and field investigations, it is proposed that achieving sustainable development of debris-flow fans requires a practical approach that integrates three key components: spatial land-use planning, in situ monitoring of debris flows and the environment, and land-use adjustment and management. This comprehensive and integrated approach is essential for effectively managing and mitigating the risks associated with debris flows, ensuring sustainable development in vulnerable areas.

Valorizing date seeds through ultrasonication to enhance quality attributes of dough and biscuit: Part 2 – Study on bioactive properties, sensory acceptance, in vitro gastrointestinal digestion and shelf life of biscuits

Aligning with sustainable food system development, in this study, date seeds were utilized to formulate value-added biscuits. Ultrasound-assisted extraction (UAE) was employed as a non-thermal method to extract polyphenolic compounds from small, medium and large particles of defatted date seed powder (DDSP). The remaining fiber-rich fraction (residue) was further utilized. Water content in biscuit formulation was replaced by the extract, and the fiber-rich fraction was substituted at three substitution levels; 2.5 %, 5 % and 7.5 %. Effects of baking on bioactive properties of dough, nutrient composition, sensory analysis, bioaccessibility of polyphenols, and shelf-life of biscuits were analyzed. Total phenolic content (TPC) increased in dough and biscuit with incorporated fiber-rich fraction. TPC of dough decreased with increasing particle size of fiber-rich fraction while biscuits exhibited an opposite trend. Similar tendency was observed with antioxidant activity of dough and biscuit. TPC was higher in biscuits than dough, with the highest values of 0.46 mg gallic acid equivalents (GAE)/g and 2.26 mg GAE/g in dough and biscuit, respectively. Fiber and moisture contents in biscuits increased while protein content decreased with fortification. Consumers showed moderate acceptance of fortified biscuits. Bioaccessibility index of polyphenols upon gastrointestinal digestion was high in biscuits with 5 % and 7.5 % substitution of small and medium sized particles of fiber-rich fraction. Phenolic retention increased with fiber fortification and at the end of 6 months the lowest thiobarbituric acid reactive substances (TBARS) value of 18.23 nmol malondialdehyde (MDA)/g sample, was observed in 7.5 % large particle substituted biscuit. Thus, utilizing date seeds in the form of green extracted polyphenols and fiber-rich fraction, as functional and bioactive ingredients highlight sustainable processing and utilization of date-fruit processing by-products.

Mathematical model of velocity and distribution law in gas lift reverse circulation well washing flow field for drilling shaft sinking

To reveal the velocity distribution law of a gas lift reverse circulation well washing flow field in drilling shaft sinking, a velocity mathematical model of well washing flow field is established. The theoretical analytical solutions and velocity distribution laws in the drill pipe and bottom hole were provided and validated through numerical simulations and similar model tests. Furthermore, this study explores the impacts of mud circulation, wind pressure, rock debris, and mud properties on the flow field distribution, presenting the sensitivity order of the factors. This study indicated the following findings. (1) The velocity theoretical model of well washing flow field was validated through numerical simulation and similar model tests, and the relative error ranged from 4.2 to 18.5%, demonstrating the high consistency. (2) The rock debris and mud experienced slight and consistent deceleration within the drill pipe. Upon reaching the gas input end, the axial upward return of the multiphase flow resulted in a “jumping” sharp increase. (3) The mud circulation, wind pressure, and void fraction positively correlated with the multiphase fluid velocity in the drill pipe, but negatively correlated with the mud density and slag content. The axial upward velocity of the rock debris decreased with increasing particle size and density. (4) The sensitivity of each factor to the discharge speed of rock debris was summarized as follows: air content > mud circulation > wind pressure > mud density > rock debris density > rock debris particle size > slag content. These findings could offer a theoretical basis for selecting well washing parameters and enhancing drilling and washing efficiency.

Morphological evolution and surface orientation effects of nickel manganese oxide in the preparation of LNMO cathode material

The study investigated the evolution of LNMO (LiNi0.5Mn1.5O4) morphology and surface orientation as a function of increasing temperature. The results show that at an initial calcination temperature of 750 °C, LNMO exhibits spherical polyhedral with (111), (110), and (100) facets and relatively small particle sizes. In response to increasing temperatures, the particle size increases, the number of crystal facets decreases, and the material ultimately transitions to a typical spinel structure. Notably, the LNMO material calcined at 750 °C demonstrates a high lithium-ion migration rate, retaining 81.24% of its capacity after 500 cycles at a 2 C rate. This exceptional performance is attributed to the exposure of multiple crystal facets, suitable particle size, and the presence of Mn³⁺, which collectively stabilize the crystal structure and provide suitable pathways for Li⁺ transport.

Impact of storage temperature on physical stability and protein-lipid Co-oxidation in whey protein functional emulsions

The aim of this study was to investigate the effect of different storage temperatures (4 °C, 25 °C and 45 °C, denoted as T-4, T-25 and T-45, respectively) on the physical stability and protein-lipid co-oxidation of whey protein functional emulsions during the storage period at storage times of 1, 2, 3 and 6 months. At the 6th month of storage, samples stored at 45 °C were less physically stable than samples stored at 4 °C, as evidenced by an increase in particle size (5.50%), a decrease in zeta potential (7.93%), and a decrease in adsorbed protein concentration (36.8%). The most severe protein-lipid co-oxidation was induced in whey protein functional emulsions under 45 °C temperature conditions with increasing storage time. Protein oxidation products (carbonyls, N′-formyl-L-kynurenine, and sulfhydryl groups) and lipid oxidation products (lipid hydroperoxides, thiobarbituric acid reactive substances) were at their highest levels, and significant molecular changes were observed in the molecules of adsorbed protein or unadsorbed proteins. As the storage temperature rises it exposes the active sites such as internal sulfhydryl and hydrophobic groups in the protein, promoting cross-linking and aggregation. Cluster and correlation analyses showed that protein-lipid co-oxidation of emulsions inevitably occurs during storage, but low-temperature storage can delay this process. This study is of guiding significance for the quality maintenance of functional nutritional emulsions and the selection of storage conditions. In addition, this study may provide clearer solutions to the problems of whey protein denaturation and formation of lipid oxides caused by protein-lipid co-oxidation in the food industry, as well as to the problem of increasing the shelf life of products by choosing the appropriate storage, packaging, and transportation temperatures.

Impact of fluid abrasive viscosity on machining performance

ABSTRACT Abrasive Flow Machining is widely employed for machining complex internal surfaces, with the fluid abrasive being crucial to machining quality. However, research on fluid abrasive performance is limited, and no standardized evaluation method exists. This paper developed a siloxane-based fluid abrasive and analyzed the impact of its viscosity on material removal. Through processing experiments, the effects of abrasive grain size and content on machining quality were explored. And the viscosity curve of the fluid abrasive was fitted. Results showed that reducing abrasive content from 60% to 40% increased surface roughness by 15.567% and decreased material removal depth by 56.623%. In contrast, increasing particle size from 80μm to 700μm decreased surface roughness by 47.057% and boosted material removal depth by 115.350%. The Cross equation provides the best fit for the viscosity curve (R² > 0.990). Finally, a novel method for evaluating fluid abrasive performance was proposed and validated.

Dependence of the hydrate-based CO2 storage characteristics on sand particle size and clay content in unconsolidated sediments

Storing carbon dioxide (CO2) in the form of hydrate in marine sediments is considered an effective way of carbon reduction. Understanding the influence of sediment properties on CO2 hydrate formation is important for the site selection of CO2 hydrate storage in marine sediments. In this study, the effects of sand particle size and bentonite content on the kinetics of CO2 hydrate formation are analyzed using low-field nuclear magnetic resonance technology, and the hydrate-based liquid CO2 storage capacity is evaluated. Results show that CO2 hydrate forms preferentially in large pores of sand samples, the water content in small pores begins to decrease before the hydrate saturation reaches 20%, and the unhydrated water mainly concentrates in small pores. With the increase of sand particle size, the CO2 storage rate of the early rapid growth stage increases first and then decreases, the CO2 storage rate of the whole hydrate formation process decreases continuously, but the final CO2 storage density is weakly affected by sand particle size. With the increase of hydrate saturation, the CO2 storage rate undergoes a trend of rapid decrease, stability, rapid decrease, and low-speed decrease in sequence. The larger the sand particle size or the higher the bentonite content, the shorter the stability stage of CO2 storage rate. The effect of bentonite on CO2 storage rate is the promotion at low content, the inhibition at medium content, and the weakening of inhibition at high content. The sediments with more than 25% bentonite are beneficial to the storage of more CO2.

Unique features of plasmonic absorption in ultrafine metal nanoparticles: unity and rivalry of volumetric compression and spill-out effect

Abstract We present a solution to a longstanding challenge in nanoplasmonics and colloid chemistry: the anomalous optical absorption of noble metal nanoparticles in the ultrafine size range of 2.5–10 nm, characterized by a rapid long-wavelength shift in plasmon resonance as the particle size increases. Our investigation delves into the impact of alterations in electron density along the radial direction of nanoparticles and the resulting variations in dielectric constants on the spectral positioning of the plasmon resonance. We explore the interplay of the spill-out effect, volumetric compression, and their combined impact in different experimental conditions on electron density variation within the particle volume and its blurring at the particle boundary. The latter effectively forms a surface layer with altered dielectric constants and a size-independent extent. As particle size decreases, the influence of the surface layer becomes more pronounced, especially when its extent is comparable to the particle radius. These findings are specific to ultrafine plasmonic nanoparticles and highlight their unique properties.

Exploring Multi-Parameter Effects on Iron Oxide Nanoparticle Synthesis by SAXS Analysis

Iron oxide nanoparticles (IONs) are extensively used in biomedical applications due to their unique magnetic properties. This study optimized ION synthesis via the co-precipitation method, exploring the impact of the reactant concentrations (Fe(II) and Fe(III)), NaOH concentration, temperature (30 °C–80 °C), stirring speed (0–1000 rpm), and dosing rate (10–600 s) on particle size and growth. Using small-angle X-ray scattering (SAXS), we observed, for example, that higher temperatures (e.g., 67 °C compared with 53 °C) led to a 50% increase in particle size, while the stirring speed and NaOH concentration also influenced nucleation and aggregation. These results provide comprehensive insights into optimizing synthetic conditions for targeted applications in biomedical fields, such as drug delivery and magnetic resonance imaging (MRI), where precise control over nanoparticle size and properties is crucial.

Effects of amino alcohols-intercalated MgAl-LDH nanocomposites on the properties of sulfoaluminate cement-based materials

Sulfoaluminate cement-based materials (SCBMs) have low mechanical properties in the early stages when they are used in grouting reinforcement engineering. The mechanical properties of cement-based materials can be improved by nanotechnology. Hydrotalcite is a layered anionic clay with adjustable interlayer anions and nanometer spacing. To date, the effect of amino alcohols (ethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA))-intercalated MgAl-layered double hydroxides (LDH) nanocomposites (denoted as MgAl-LDH-TEA, MgAl-LDH-DEA, and MgAl-LDH-MEA) on the properties of SCBMs have not been studied. Herein, we demonstrate that intercalated MgAl-LDH exhibit a decrease in crystallinity, an increase in particle size, and improved early mechanical properties compared to unmodified LDHs. MgAl-LDH modified by TEA, DEA, and MEA all have a nucleation effect and provide nucleation sites for ettringite. Simultaneously, the intercalated hydrotalcite can release higher concentrations of magnesium ions into the slurry, forming a magnesium-containing ettringite phase and accelerating the hydration of SCBMs. Modified MgAl-LDH can also release amino alcohols, affecting the hydration process of the paste. The modified LDHs affect the hydration and compressive strength of SCBMs owing to the combined action of the nucleation of LDHs and the release of magnesium ions and amino alcohols compounds.

Evaluating microplastic particles as vectors of exposure for plastic additive chemicals using a food web model

Microplastic particles (MPs) represent potential hazards for humans and wildlife, including as vectors for chemical exposure (e.g. plastic additives and pollutants sorbed from the surrounding environment). The leaching of chemicals from MPs has been identified as a potential exposure pathway but the relative magnitude of this pathway under environmentally relevant conditions remains unclear. Here, we describe a modification of the ACC-HUMANSTEADY bioaccumulation model to include dietary exposure to MPs containing either accumulated chemicals from the surrounding environment or embedded plastic additive chemicals (PACs). Chemical transfer to humans and wildlife is described using two-film resistance concepts assuming spheroidal particles of different sizes. The relative contribution of MPs and environmental media to the estimated daily chemical intake in humans was assessed in various exposure scenarios, for a range of hypothetical chemicals with varying octanol-water and air-water partition coefficients (KOW and KAW, respectively; i.e. 0 < log KOW <8 and − 5 < log KAW < 3). Results imply that MPs could act as sources of exposure to chemical additives when the ingestion rate of 1 μm MPs is ≥ 10 mg d− 1, and the concentration of hydrophobic plastic additive is ≥ 5% wt wt− 1. The contribution made by MPs as vectors of exposure decreased with increasing particle size and decreasing ingestion rates of MPs. Human health risks were evaluated for four specific PACs to illustrate the application of the model for risk assessment. Risks were negligible when the ingestion rate of MPs was < 100 μg d− 1. Uncertainties are high regarding the characterization and quantification of ingestion of MPs by humans and wildlife, including particle sizes and polymer composition, as well as on the presence of PACs in MPs. These data gaps need to be addressed if the issue of MPs as vectors of chemical exposure is to be fully understood. The work illustrates that mechanistic models, which account for all major exposure pathways, can be used to identify the importance of different exposure pathways, help prioritize research needs and support decision making.

89Zr-Labeled DFO@Durvalumab-HSA nanoparticles: In vitro potential for triple-negative breast cancer.

This study presents the development and evaluation of a DFO@mAb-NP (DFO@Durvalumab-HSA-DTX nanoparticle) nanoplatform for imaging in triple-negative breast cancer (TNBC). The nanoplatform demonstrated significant changes postconjugation with DFO, evidenced by increased particle size from 178.1 ± 5 nm to 311 ± 26 nm and zeta potential alteration from -31.9 ± 3 mV to -40.5 ± 0.8 mV. Fourier-transform infrared spectroscopy and ultraviolet spectral analyses confirmed successful DFO conjugation, with notable shifts in peak wavelengths. High labeling efficiency was achieved with 89Zr, as indicated by thin layer radio chromatography and high-performance liquid radio chromatography results, with labeling efficiencies of 98 ± 2% for 89Zr-DFO@mAb and 96 ± 3% for 89Zr-DFO@mAb-NP. The nanoplatforms maintained stability over 24 h, showing less than 5% degradation. Lipophilicity assays revealed logP values of 0.5 ± 0.03 for 89Zr-DFO@mAb-NP and 0.98 ± 0.2 for 89Zr-DFO@mAb, indicating a higher lipophilic tendency in the radiolabeled Durvalumab. Cell uptake experiments showed an initial high uptake in MDA-MB-468 cells (45.1 ± 3.2%), which decreased over time, highlighting receptor-specific interactions. These comprehensive findings suggest the promising potential of the DFO@mAb-NP nanoplatform for targeted imaging in TNBC, with implications for improved diagnostic accuracy and treatment strategies.