Particle Counter Research Articles

Unlocking the nanoparticle emission potential: a study of varied filaments in 3D printing.

This study investigates nanoparticle emission during 3D printing processes, assessing various filament materials' impact on air quality. Commonly used 3D printers, including both filament and resin-based types, were examined. The study's scope encompasses diverse filament materials like ABS (acrylonitrile butadiene styrene), PLA (polylactic acid), PETG (polyethylene terephthalate glycol), ASA (acrylonitrile styrene acrylate), TPU (thermoplastic polyurethane), PP (polypropylene), nylon, and wood-based variants, alongside three types of resins. The research delves into the relationship between the type of material and nanoparticle emissions, emphasizing temperature's pivotal role. Measurement instruments were employed for nanoparticle quantification, including an engine exhaust particle sizer spectrometer, condensation particle counter, and nanozen dust counters. Notably, results reveal substantial variations in nanoparticle emissions among different filament materials, with ASA, TPU, PP, and ABS showing considerably elevated emission levels and characteristic particle size distribution patterns. The findings prompt practical recommendations for reducing nanoparticle exposure, emphasizing printer confinement, material selection, and adequate ventilation. This study offers insights into potential health risks associated with 3D printing emissions and provides a basis for adopting preventive measures.

Improving Aerosol Characterization Using an Optical Particle Counter Coupled with a Quartz Crystal Microbalance with an Integrated Microheater

Aerosols, as well as suspended particulate matter, impact atmospheric pollution, the climate, and human health, directly or indirectly. Particle size, chemical composition, and other aerosol characteristics are determinant factors for atmospheric pollution dynamics and more. In the last decade, low-cost devices have been widely used in instrumentation to measure aerosols. However, they present some issues, such as the problem of discriminating whether the aerosol is composed of liquid particles or solid. This issue could lead to errors in the estimation of mass concentration in monitoring environments where there is fog. In this study, we investigate the use of an optical particle counter (OPC) coupled to a quartz crystal microbalance with an integrated microheater (H-QCM) to enhance measurement performances. The H-QCM was used not only to measure the collected mass on its surface but also, by using the integrated microheater, it was able to heat the collected mass by performing heating cycles. In particular, we tested the developed system with aerosolized saline solutions of sodium chloride (NaCl), with three decreasing concentrations of salt and three electronic cigarette solutions (e-liquid), with different concentrations of propylene glycol and glycerin mixtures. The results showed that the OPC coherently counted the salt dilution effects, and the H-QCM output confirmed the presence of liquid and solid particles in the aerosols. In the case of e-liquid aerosols, the OPC counted the particles, and the HQCM output highlighted that in the aerosol, there were no solid particles but a liquid phase only. These findings contribute to the refinement of aerosol measurement methodologies by low-cost sensors, fostering a more comprehensive understanding.

Degradation mechanism of measuring performance of Optical Particle Counter under temperature-pressure coupling effect

Abstract To investigate the degradation mechanism of measuring the performance of an Optical Particle Counter (OPC) under temperature-pressure coupling, this study first establishes a theoretical calculation model of gas refractive index, and then elucidates the comprehensive influence mechanism of temperature and pressure on gas optical properties. Furthermore, the experimental measurement technique and measuring device for gas refractive index are built. By comparing the theoretical and experimental results in the temperature range of 48-560°C and the pressure range of 0.9-4.6 MPa, the difference between the two errors is just 0.05%, indicating the accuracy of the theoretical model of the refractive index of gas. Secondly, a dynamic model of Optical Measurement Volume (OMV) under high-temperature and high-pressure conditions was established using geometrical optics theory, and the impacts of gas temperature and pressure variations on OPC measurement performance were investigated. The gas temperature (100-1000 °C) and pressure (1-4.6 MPa) are shown to have opposing effects on the OMV, with gas pressure being more relevant. Finally, in order to eliminate the effect of gas refractive index change on the optical measurement performance of OPC, a parallel light model is proposed to solve the problem of the degradation of OPC measurement performance under temperature and pressure coupling conditions.

Particle analysis of surgical lung biopsies from deployed and non-deployed US service members during the Global War on Terrorism.

The role that inhaled particulate matter plays in the development of post-deployment lung disease among US service members deployed to Southwest Asia during the Global War on Terrorism has been difficult to define. There is a persistent gap in data addressing the relationship between relatively short-term (months to a few years) exposures to high levels of particulate matter during deployment and the subsequent development of adverse pulmonary outcomes. Surgical lung biopsies from deployed service members and veterans (DSMs) and non-deployed service members and veterans (NDSMs) who develop lung diseases can be analyzed to potentially identify residual deployment-specific particles and develop associations with pulmonary pathological diagnoses. We examined 52 surgical lung biopsies from 25 DSMs and 27 NDSMs using field emission scanning electron microscopy (FE-SEM) with energy dispersive x-ray spectroscopy (EDS) to identify any between-group differences in the number and composition of retained inorganic particles, then compared the particle analysis results with the original histopathologic diagnoses. We recorded a higher number of total particles in biopsies from DSMs than from NDSMs, and this difference was mainly accounted for by geologic clays (illite, kaolinite), feldspars, quartz/silica, and titanium-rich silicate mixtures. Biopsies from DSMs deployed to other Southwest Asia regions (SWA-Other) had higher particle counts than those from DSMs primarily deployed to Iraq or Afghanistan, due mainly to illite. Distinct deployment-specific particles were not identified. Particles did not qualitatively associate with country of deployment. The individual diagnoses of the DSMs and NDSMs were not associated with elevated levels of total particles, metals, cerium oxide, or titanium dioxide particles. These results support the examination of particle-related lung disease in DSMs in the context of comparison groups, such as NDSMs, to assist in determining the strength of associations between specific pulmonary pathology diagnoses and deployment-specific inorganic particulate matter exposure.

Integrated design optimization method for pavement structure and materials based on further development of finite element and particle swarm optimization algorithm

The maintenance design for existing asphalt pavements, characterized by their typical structure and material composition, falls short of meeting the diverse requirements of pavements. There is an urgent need for a more rational design approach that can achieve accurate pavement design while also reducing construction costs. This paper focuses on selected conventional road surface structures and conducts an analysis of how pavement structure and materials impact fatigue life and construction expenses. It employs Python to perform three-dimensional finite element road modeling, analysis, and data extraction at specific locations, using normalized fatigue equation to calculate pavement fatigue life. The optimization variables selected are the modulus E and thickness h, with pavement maintenance cost serving as the optimization target function. The particle swarm optimization algorithm is employed for optimizing these variables. A comparative analysis is carried out for five improved optimization algorithms, optimizing combinations of inertia weight, learning factors, particle speed, number of particles, and iteration times. The results reveal that the enhanced optimization algorithms significantly improve iteration trends, featuring velocity limitations and natural selection mechanisms. Between 0 and 20 iterations, all algorithms search for the optimal solution over a wider interval with greater fluctuations. Between 20 and 30 iterations, each algorithm gradually converges towards its solution, stabilizing in the later stages. Based on optimization speed and actual engineering cost benchmarks, the NDPSO algorithm is selected, resulting in a 52.8% reduction in actual engineering costs. Adjustments to the particle count and iteration number of the NDPSO algorithm are made based on computational cost and optimization accuracy, thus choosing 20 particles and 50 iterations as the recommended parameter combination. By combining automated finite element modeling, analysis, and particle swarm optimization, this paper offers a novel and effective automated design reference for extending the lifespan of asphalt pavement structures.

Gas Evolution Kinetics in Overlithiated Positive Electrodes and its Impact on Electrode Design.

Increasing lithium contents within the lattice of positive electrode materials is projected in pursuit of high-energy-density batteries. However, it intensifies the release of lattice oxygen and subsequent gas evolution during operations. This poses significant challenges for managing internal pressure of batteries, particularly in terms of the management of gas evolution in composite electrodes-an area that remains largely unexplored. Conventional assumptions postulate that the total gas evolution is estimated by multiplying the total particle count by the quantities of gas products from an individual particle. Contrarily, this investigation on overlithiated materials-a system known to release the lattice oxygen-demonstrates that loading densities and inter-particle spacing in electrodes significantly govern gas evolution rates, leading to distinct extents of gas formation despite of an equivalent quantity of released lattice oxygen. Remarkably, this study discoveres that O2 and CO2 evolution rates are proportional to 1O2 concentration by the factor of second and first-order, respectively. This indicates an exceptionally greater change in the evolution rate of O2 compared to CO2 depending on local 1O2 concentration. These insights pave new routes for more sophisticated approaches to manage gas evolution within high-energy-density batteries.

ПЛАНИРОВАНИЕ И РЕАЛИЗАЦИЯ СТРОИТЕЛЬНЫХ РАБОТ ПРИ ТОЧЕЧНОЙ ЗАСТРОЙКЕ ДЛЯ ОПРЕДЕЛЕНИЯ УДЕЛЬНЫХ ПЫЛЕВЫХ ВЫБРОСОВ

Abstract. The construction industry is one of the significant sources of environmental damage. The effects of dust pollution have an impact on all stages of the building's life cycle, from the start of work on the construction site to completion, operation and demolition. Despite the fact that the stage of work implementation does not last long in comparison with other stages of the life cycle of an investment and construction project, the construction stage has a number of significant impacts on the environment. The development of the construction industry requires the comprehensive assessment and investigation of the construction site as a source of pollu-tion, identification and evaluation of all sources of dust pollution on the construction site, the processes of dust pollution propagation in an urban environment. 
 The article offers an analysis of data on field studies of the degree of atmospheric air pollution in the territory of Rostov-on-Don, an analysis of the volume of construction dust emissions from construction works, a method for calculating control over the implementation of construction processes and the spread of dust pollution generated in the atmospheric air, indi-cators of the maximum, average daily emission concentration of fine dust PM2.5 and PM10 formed from construction production and the ability to control the level of pollution on the construction site. There are no fundamental studies on the calculation of dust emission from construction works during spot construction. Based on the field studies conducted earlier using the Handheld 3016 particle counter, data on dust emissions from construction processes under various climatic influences were obtained.
 Subject: analysis of data on field studies of the degree of atmospheric air dustiness in the territory of Rostov-on-Don, the volume of emissions of construction dust from construction work on construction sites in urban conditions.
 Materials and methods: conducting systematic measurements of the degree of dust in Rostov-on-Don using the Lighthouse Handheld 3016 IAQ manual particle counter, taking into account typical climatic, heterogeneous factors of the territory on which the city is located. Systematic monitoring of several construction sites where residential complexes similar in technology and conditions were built in the most dusty area of Rostov-on-Don and the selection of five construction sites for the development of a calendar schedule for construction and installation work, taking into account specific emissions of dust particles and climatic conditions for calculating the dust pollution factor.
 Results: an effective approach that can be usefully applied to the determination of dust emissions on the construction site, to calculate the gross emission of dust released on the site from construction work, daily indicators of the maximum single and average daily concentration, as well as to dust dispersion with the determination of zones exceeding the MPC indicators is the use of network modeling with further calendarization to predict these types of indicators during the design and implementation of construction production.
 Conclusions: based on the data obtained, it can be concluded that with the existing implemented organization and technology of work, the concentration of fine dust particles are within the MPC, but given the background concentrations of atmospheric air in Rostov-on-Don, these indicators in a particular area will exceed the permissible MPC. The process of using existing SMR models taking into account specific dust emissions, the development of a schedule of dust pollution of a specific territory taking into account natural and climatic factors and the determination of zones of excess of MPC indicators in the process of modeling the dispersion of fine dust particles beyond the fence boundaries of the construction site will make it possible to draw up a passport of environmental safety of the nearby urbanized territory during spot development. Daily determination of dust pollution indicators will allow you to adjust the schedule of construction work. Modeling the dispersion of construction dust, taking into account the direction and speed of the wind, will make it possible to monitor the zones of exceeding the MPC of the neighboring territory on a daily basis and adjust measures to extinguish dust emissions at the construction site.

A comparative study of a standard slit-to-agar sampler and a real-time bacterial detector

A comparison is presented of data from simultaneous measurements of airborne particles by a standard slit-to-agar sampler (STA) and of fluorescent particles by a real-time bacterial detector, Bio Aerosol Monitoring System (BAMS) during an evaluation regarding emitted airborne particles of a surgical clothing system in a test chamber. Data from simultaneous orientating measurements of airborne particles by a standard discrete particle counter are also discussed. The results show that in an environment with a low level of airborne particles including CFUs and man the only contamination source, there is a moderate correlation between the number of aerobic CFU and BAMS viable, i.e., fluorescence, particles, when the slit-to-agar sampler is registering/collecting within its detection level. Different environments need simultaneous measurements by an STA in aerobic CFU/m³ and by a BAMS in viable particles/m³ to set up the correlation between the two methods. Keywords: Airborne particles, controlled environment, CFU, fluorescent particles, real-time measurements, viable particles.

331 Validation of a Novel CSF-Based Biomarker of Mitochondrial Function

OBJECTIVES/GOALS: Determine the exosome mitochondrial DNA (mtDNA) copy number in cerebrospinal fluid (CSF) as a measure of neuronal mitochondrial integrity in patients with subarachnoid hemorrhage (SAH). Determine the patterns of beta amyloid and tau protein biology in CSF of SAH patients and correlate those measures with the clinical status of the SAH patients. METHODS/STUDY POPULATION: The CSF is collected from SAH patients undergoing ventriculostomy-based continuous CSF drainage. Adults from all ethnicities and sex are included in this study. The exosomes are isolated from CSF samples using a precipitation method and particle count and size are measured using NanoSight. The DNA is extracted using an exosomal DNA isolation kit (XCF kit). The CSF mtDNA copy number is measured using digital drop PCR with mitochondrial DNA primers. The levels of beta-amyloid (a-beta-40 and -42) and tau protein in CSF are measured using a sensitive ELISA-based assay. A quantitative evaluation of mitochondrial DNA copy number, clinical status of the SAH patients and beta amyloid, and tau protein levels will be conducted and reported. RESULTS/ANTICIPATED RESULTS: Preliminary results of four CSF samples showed similar patterns in CSF exosome particle number, particle size and exosomal mtDNA copy number in relation to samples from the admission day. Particle number decreased with time while particle size increased. More patient samples will be analyzed to confirm the patterns. We anticipate that mtDNA copy number will correlate with brain beta-amyloid and tau protein levels. Moreover, we anticipate that the clinical status of the SAH patients will associate with the mtDNA copy number. We specifically predict that higher mtDNA copy number levels will correlate with better clinical outcomes. DISCUSSION/SIGNIFICANCE: Mitochondrial function is critical to brain health, but we lack effective ways to monitor this parameter. Here we focus on a CSF based biomarker, exosome-derived mtDNA, which is intended to reflect the integrity of brain mitochondria. As bioenergetic metabolism influences beta amyloid and tau biology, predicting those levels are important.

Counting alpha particles produced by radon daughters using commercial off-the-shelf complementary metal oxide semiconductor (COTS CMOS) image sensors

Radon (Rn-222) is the main source of radiation exposure to human beings from natural radiation; it is of great significance to study the measuring methods and measuring instruments of radon for natural radiation protection. In recent years, the application of pixel detectors in radiation detection has attracted attention. In this paper, a Commercial Off-the-Shelf Complementary Metal Oxide Semiconductor (COTS CMOS) image sensor which replaces the glass for protection covering in front of the sensors was used to perform a series of measurements to identify alpha particles. During the experiment, the CMOS image sensor was used to record a video during the sampling period, and then use the FFmpeg software to take screenshots of the video by frame. MATLAB was used to count bright spots from the image frames. A measurement chamber was designed to measure radon concentrations, and when the relative humidity was constant, the count of alpha particles by the CMOS image sensor increased along with the increase of the concentration. The experiments verified the feasibility of the low-cost COTS CMOS image sensors to monitor radon.

BACK TO THE FUTURE: COMPARING YEAST AS AN OUTMODED ARTIFICIAL TRACER FOR SIMULATING MICROBIAL TRANSPORT IN KARST AQUIFER SYSTEMS TO MORE MODERN APPROACHES

Bacterial contamination of karst groundwater is a major concern for public health. Artificial tracing studies are crucial for establishing links between locations where pollutants can rapidly reach the aquifer systems and subsequent receptors, as well as for enhanced understanding of pollutant transport. However, widely used solute artificial tracers do not always move through the subsurface in the same manner as particles and microorganisms, hence may not be ideal proxies for predicting movement of bacterial contaminants. This study evaluates whether a historically used microbial tracer (yeast) which is readily available, inexpensive, and environmentally friendly, but usually overlooked in modern karst hydrogeological studies due to challenges associated with its detection and quantification in the past, can reemerge as a valuable tracer using the latest technology for its detection. Two field-based studies on separate karst systems were carried out during low-flow conditions using a portable particle counter along with flow cytometry measurements to monitor the recovery of the yeast at the springs. Soluble fluorescent dyes were also injected simultaneously with the yeast for comparison of transport dynamics. On one tracer test, through a karst conduit of much higher velocities, the injected yeast and fluorescent dye arrived at the same time at the spring, in comparison to the tracer test on a conduit system with lower groundwater velocities in which the yeast particles were detected before the dye at the sampling site. Both a portable particle counter and flow cytometry successfully detected yeast during both tests, thereby demonstrating the applicability of this tracer with contemporary instrumentation. Even though no significant advantages of flow cytometry over the portable counter system can be reported on the basis of the presented results, this study has shown that flow cytometry can be successfully used to detect and quantify introduced microbial tracers in karst environments with extremely high precision.

Stability and compatibility of an intramuscular fetal anesthetic cocktail for fetal intervention.

To evaluate chemical stability and physical compatibility when combining fentanyl, rocuronium, and atropine in a fixed ratio to support intramuscular drug delivery during fetal intervention and surgery. A highly concentrated combination of fentanyl, rocuronium, and atropine was created based on common prescribing practices at a maternal fetal care center. Chemical stability testing was completed using liquid chromatograph mass spectrometry-mass spectrometry (LC/MS-MS) to detect and quantitate atropine, rocuronium, and fentanyl, with fentanyl-d5 being an internal standard at 6-, 12, 24-, and 36-hours following sample preparation. Physical compatibility testing was completed using United State Pharmacopeia (USP)<788> recommended analytical technique of light obscuration (LO) in addition to novel backgrounded membrane imaging (BMI) at 6- and 24-hours following sample preparation. Physical compatibility was determined using USP<788> particle count limits for both techniques. Based on LC/MS-MS results, the samples retained expected medication concentrations at all time points tested. For physical compatibility testing, the particle counts met criteria to be considered compatible per USP<788> large volume particle count thresholds at 6 hours by both methods but exceeded tolerable thresholds at 24 hours. The combination of rocuronium, fentanyl, and atropine for intramuscular fetal administration are physically compatible and chemically stable for 6 hours.

Absolute protein quantification based on calibrated particle counting using electrospray-differential mobility analysis

The traceability of in vitro diagnostics or drug products is based on the accurate quantification of proteins. In this study, we developed an absolute quantification approach for proteins. This method is based on calibrated particle counting using electrospray-differential mobility analysis (ES-DMA) coupled with a condensation particle counter (CPC). The absolute concentration of proteins was quantified with the observed protein particle number measured with ES-DMA-CPC, and the detection efficiency was determined by calibrators. The measurement performance and quantitative level were verified using two certificated reference materials, BSA and NIMCmAb. The linear regression fit for the detection efficiency values of three reference materials and one highly purified protein (myoglobin, BSA, NIMCmAb and fibrinogen) indicated that the detection efficiency and the particle size distribution of these proteins exhibited a linear relationship. Moreover, to explore the suitability of the detection efficiency-particle size curve for protein quantification, the concentrations of three typical proteinaceous particles, including two high molecular weight proteins (NIST reference material 8671 and D-dimer) and one protein complex (glutathione S-transferase dimer), were determined. This work suggests that this calibrated particle counting method is an efficient approach for nondestructive, rapid and accurate quantification of proteins, especially for measuring proteinaceous particles with tremendous size and without reference standards.

Analytical Characterization of Heterogeneities in mRNA-Lipid Nanoparticles Using Sucrose Density Gradient Ultracentrifugation.

Rational design and robust formulation processes are critical for optimal delivery of mRNA by lipid nanoparticles (LNPs). Varying degrees of heterogeneity in mRNA-LNPs can affect their biophysical and functional properties. Given the profound complexity of mRNA-LNPs, it is critical to develop comprehensive and orthogonal analytical techniques for a better understanding of these formulations. To this end, we developed a robust ultracentrifugation method for density-based separation of subpopulations of mRNA-LNPs. Four LNP formulations encapsulating human erythropoietin (hEPO) with varying functionalities were synthesized using two ionizable lipids, A and B, and two helper lipids, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and 1,2-dierucoyl-sn-glycero-3-phosphoethanolamine (DEPE), along with cholesterol and DMG-PEG-2K. Upon ultracentrifugation on a sucrose gradient, a distinct pattern of "fractions" was observed across the gradient, from the less dense topmost fraction to the increasingly denser bottom fractions, which were harvested for comprehensive analyses. Parent LNPs, A-DOPE and B-DOPE, were resolved into three density-based fractions, each differing significantly in the hEPO expression following intravenous and intramuscular routes of administration. Parent B-DEPE LNPs resolved into two density-based fractions, with most of the payload and lipid content being attributed to the topmost fraction compared to the lower one, indicating some degree of heterogeneity, while parent A-DEPE LNPs showed remarkable homogeneity, as indicated by comparable in vivo potency, lipid numbers, and particle count among the three density-based fractions. This study is the first to demonstrate the application of density gradient-based ultracentrifugation (DGC) for a head-to-head comparison of heterogeneity as a function of biological performance and biophysical characteristics of parent mRNA-LNPs and their subpopulations.

Understanding and mitigating temperature-induced agglomeration in silica-based chemical mechanical planarization (CMP) slurry storage

This study explores the impact of temperature on silica particle agglomeration in Chemical Mechanical Planarization (CMP) slurries during storage. Slurries were stored at 15 °C, room temperature, and 45 °C, and analyzed. ATR-FTIR, RAMAN, SEM, zeta potential, and LPC were employed providing qualitative and quantitative data on slurry stability and agglomeration tendencies. Elevated temperature storage significantly increased agglomeration and large particle counts with particle counts value of ∼1.2×107 Part./ml, likely due to water molecule dehydration leading to destabilization. Low-temperature storage also induced agglomeration but to a lesser extent with particle counts the value of ∼4.0×106 Part./ml compared with the RT (∼2.0×106 Part./ml). Short-term storage yielded soft agglomerates with LPC of ∼(2.0–4.0)×106 Part./ml, while long-term high-temperature storage led to hard agglomerates with LPC of ∼3.0×107 Part./ml. The ATR-FTIR and Raman analysis indicate that the spectroscopic features of the original slurry exhibited changes upon variation of storage temperature from RT to 15 and 45 °C. The study also explored the reversibility of agglomeration post-treatment, indicating a potential mitigation pathway. The results demonstrated an inverse relationship between temperature and dissolved oxygen (DO) in silica slurries. For example. the curves depict a decrease in oxygen content from ∼10 ppm at RT to 7 ppm at 45 °C with increasing aging time. A mechanism outlining the temperature and aging-induced agglomeration was proposed, linking temperature fluctuations and thermodynamic aspects to colloidal stability. These findings offer a robust understanding of temperature-induced agglomeration in silica-based CMP slurry storage, paving the way for developing strategies to alleviate these issues and ensuring consistent CMP performance in semiconductor manufacturing.

How many microplastics do you need to (sub)sample?

Analysis of microplastics in the environment requires polymer characterization as a confirmation step for suspected microplastic particles found in a sample. Material characterization is costly and can take a long time per particle. When microplastic particle counts are high, many researchers cannot characterize every particle in their sample due to time or monetary constraints. Moreover, characterizing every particle in samples with high plastic particle counts is unnecessary for describing the sample properties. We propose an a priori approach to determine the number of suspected microplastic particles in a sample that should be randomly subsampled for characterization to accurately assess the polymer distribution in the environmental sample. The proposed equation is well-founded in statistics literature and was validated using published microplastic data and simulations for typical microplastic subsampling routines. We report values from the whole equation but also derive a simple way to calculate the necessary particle count for samples or subsamples by taking the error to the power of negative two. Assuming an error of 0.05 (5 %) with a confidence interval of 95 %, an unknown expected proportion, and a sample with many particles (> 100k), the minimum number of particles in a subsample should be 386 particles to accurately characterize the polymer distribution of the sample, given the particles are randomly characterized from the full population of suspected particles. Extending this equation to simultaneously estimate polymer, color, size, and morphology distributions reveals more particles (620) would be needed in the subsample to achieve the same high absolute error threshold for all properties. The above proposal for minimum subsample size also applies to the minimum count that should be present in samples to accurately characterize particle type presence and diversity in a given environmental compartment.

Physical compatibility of Xuebijing injection with 53 intravenous drugs during simulated Y-site administration.

Xuebijing injection (XBJ) is a commonly used herbal medicine injection in China. However, the physical compatibility of XBJ with other intravenous drugs remains unclear. The purpose of this research is to evaluate physical compatibility of Xuebijing injection (XBJ) with 53 intravenous drugs (including 31 Chinese medicine injections and 22 chemicals) during simulated Y-site administration. Y-site administration was simulated in vitro by admixing 0.33 ml/ml XBJ with an equal volume of other diluted 53 intravenous drugs, respectively. Physical compatibility including visual inspection, Tyndall beam, particle limits, turbidity, pH, chromacity value, spectroscopic absorption of 550 nm and 420 nm (A550 nm and A420 nm) were observed and assessed at 0, 1, 2, and 4 h. Physical compatibility was defined as all solutions with no color changes, no gas evolution, particulate formation and no Tyndall beam within 4 hours, turbidity changes <0.5 nephelometric turbidity unit (NTU) compared to 0 h, particle limits allowed by the Chinese Pharmacopoeia (Ch.P) 2020 edition, pH changes <10% compared to 0, chromacity value changes <200 compared to 0 h, or photometrical changes of A420 nm <0.0400 or A550 nm <0.0100 compared to 0 h. XBJ was physically incompatible with 27 of the 53 intravenous drugs tested, 26 were compatible with XBJ for 4 h. XBJ should not be simultaneously co-administered with 27 of the 53 intravenous drugs during simulated Y-site. If coadministration was inevitable, flushing tube with NS or D5W before and after infusion of XBJ was needed. Assessment included visual inspection, Tyndall beam, turbidity measurement, particle counts, pH measurement, chromacity value measurement and absorption of A550 nm were proved to be valid and robust for the quality control of infusion and compatibility of Chinese herbal injection.

Abstract 3633: Multi-parametric characterization of extracellular vesicles in the aqueous humor of uveal melanoma eyes undergoing brachytherapy

Abstract Introduction: Aqueous humor (AH), fluid in the anterior chamber of the eye, is a liquid biopsy source of tumor information in uveal melanoma (UM). Extracellular vesicles (EVs) have recently been characterized in the AH of retinoblastoma eyes, however, have not been investigated in UM. EVs are small membrane-enclosed particles secreted by virtually every cell type with a role in intercellular communications. We hypothesize that tumor-derived EVs are detectable in the AH of UM eyes and that understanding the type of vesicles present may help us better understand their function, particularly for cancer. Small extracellular vesicles (sEVs) have been shown to promote tumorigenesis, treatment resistance, and metastasis, leading to the discovery of clinically-relevant biomarkers for multiple cancer types. As the diversity and role of sEVs in the AH of UM patients has never previously been reported, this project is a first step towards investigating new biomarkers of clinical utility. Our aim is to use single particle analysis to characterize sEV subpopulations in the AH of UM patients by quantifying their size, concentration, and phenotypes based on cell surface markers, specifically tetraspanin co-expression patterns. Methods: sEVs were analyzed from paired pre- and post-brachytherapy AH samples collected from 19 UM patients. AH samples from 5 glaucoma patients served as the control cohort. Unprocessed AH underwent Nanoparticle Tracking Analysis for size quantification and Single Particle-Interferometric Reflectance Imaging Sensor analysis for fluorescent particle count and tetraspanin immunophenotyping; counts were subsequently converted to percentages for analysis. Statistics were performed using Mann-Whitney U, ANOVA, and Tukey’s tests. Results: AH derived from UM eyes (pre-brachytherapy) displayed a broader sEV size distribution than glaucoma eyes, with more diverse sEV subpopulations. Both tumor and nontumor AH samples demonstrated a dominant CD63+ sEV subpopulation. A significantly higher percentage of CD63/81+ sEVs (P= 0.0217) and CD9/63/81+ sEVs (P= 0.0146) were found in post-brachytherapy samples compared to pre-brachytherapy. Conclusions: sEV subpopulations in UM eyes demonstrate increased heterogeneity in comparison to nontumor eyes. Our results are consistent with prior studies reporting that the CD63+ sEV subtype is an AH-specific biomarker enriched across multiple ocular diseases. The increase in CD63/81+ sEVs and CD9/63/81+ sEVs after brachytherapy is presumably a result of radiation-induced release of these vesicles, suggesting a tumor-derived origin of these subpopulations. CD63/81+ sEV subpopulation was previously reported to also be a tumor-derived subpopulation in AH of retinoblastoma eyes. Further study of the cargo carried by these sEV subpopulations may uncover molecular mechanisms pivotal to UM and other ocular cancers. Citation Format: Shreya Sirivolu, Chen-Ching Peng, Paolo Neviani, Jesse L. Berry, Liya Xu. Multi-parametric characterization of extracellular vesicles in the aqueous humor of uveal melanoma eyes undergoing brachytherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3633.

Particle image based simultaneous velocity and particle concentration measurement

The aim of this study is the expansion of the application of particle image velocimetry (PIV) to include the determination of particle concentration within the visualized area, in addition to velocity analysis. The assessment of particle concentration is valuable in various lab-scale experiments involving particle dispersion. Additionally, it plays a crucial role in evaluating the quality of PIV images. The research investigates two particle image-based concentration techniques: the exponential averaging-based sliding method and the Voronoi cell-based method on the particle images. The exponential averaging method provides a straightforward approach, utilizing a constant length scale for sliding average application to particle images. However, this method may result in broadened interfaces or a ‘marker-shot’ effect at low concentrations, making it less suitable for scenarios involving highly non-uniform particle distributions, such as concentrated jet emissions into ambient environments. Consequently, detecting interfaces in such cases requires additional effort for reliable results. In contrast, the Voronoi cell-based technique offers the advantage of spatially adaptive resolution, making it well-suited for variable concentration distributions and situations where interface detection is crucial. To comprehensively evaluate the performance of these techniques, a synthetic test case was generated to simulate a diffusion problem featuring an initial step in concentration distribution. Both the exponential averaging and Voronoi cell-based methods were applied and compared using this synthetic test case. Additionally, the effect of particle–particle overlap is analyzed theoretically and experimentally with uniform concentration and comparison with particle counter measurements. A modified Voronoi method is introduced, providing flexibility in capturing a wide range of concentration regions and features. An example experimental scenario involving a turbulent puff was considered demonstrating the application of the developed methods. The results demonstrate that the Voronoi method effectively captures small structures with high concentrations while providing reliable results in regions with low concentrations.

Influence of side dilution jets on swirling and non-swirling pulverised biomass turbulent annular flows

The use of pulverised biomass in non-premixed combustion systems, featuring turbulent annular flows (swirling, non-swirling) with downstream air dilution jets, is of immense practical importance. The overall combustion performance and emissions heavily rely on the underlying flow dynamics, turbulence and dispersion behaviour of the pulverised biomass particles. Despite the practical significance of side dilution jets in aiding complete combustion and controlling pollutants, the fundamental understanding of side dilution jets influence on the biomass particle velocity field, turbulence, and dispersion characteristics is still lacking. However, the presence of a multi-phase (solid-gas) flow field, highly turbulent annular flows, swirl, and cross-wise turbulent dilution jets poses significant challenges to these investigations. This work employs a combination of two-dimensional planar Particle Image Velocimetry (PIV) experiments and three-dimensional multi-phase numerical modelling to resolve the influence of turbulent side dilution jets (Red = 18,000 and 27,000) on the particle flow and dispersion characteristics of turbulent annular jets equipped with a central pulverised biomass-laden jet. The numerical modelling uses Reynolds stress model (RSM) and discrete phase model (DPM) for the solution of gas and dispersed phases, respectively. Walnut flour based raw pulverised biomass is injected at a certain particle loading ratio (Φp=0.33 and 0.49) through a turbulent central jet (Rj = 4500) into non-swirling (S = 0) and swirling (S = 0.3) turbulent confined annular flows (Res = 35,500 and 17,800). Comprehensive Constant Temperature Anemometry (CTA) experiments are conducted to obtain well-defined boundary conditions for experiments as well as numerical simulations. Prior to numerical predictions, the models are duly validated against the experimental data.Results reveal that the characteristic flow feature of side dilution jets, i.e., peripheral recirculation zones (PRZ) significantly entrains pulverised biomass particles from the turbulent particle-laden (central jet) annular flows (both swirling and non-swirling) and alters the particle flow and turbulence characteristics. Under non-swirling conditions (S = 0), side dilution jets reduce mean particle axial velocity by 22.4% and increase turbulent fluctuating velocity by 52.6%. These figures elevate to 32.5% and 100% respectively for swirling conditions (S = 0.3), depicting enhanced turbulent mixing between solid particles and the gas phase. In terms of particle dispersion, side dilution jets significantly enhance lateral dispersion of biomass particles, particularly under swirling flow conditions. In the PRZ region, side dilution jets led to a 108% and 279% increase in normalised particle count for non-swirling and swirling cases, respectively. These findings suggest that swirl doubles the particle dispersion in the PRZ. Furthermore, a 50% increase in Red enables side dilution jets to entrain more biomass particles and disperse them into the PRZ. Conversely, a 50% increase in ṁp leads to a significant increase in particle volume fraction along the central axis of the nozzle.