Particle Counter Research Articles

Investigation of the rehydration characteristics of dairy and infant formula powders using focused beam reflectance measurement and electrical resistance tomography

The potential of focused beam reflectance measurement (FBRM) and electrical resistance tomography (ERT) was evaluated as on‐line process analytical technologies (PAT) for monitoring powder rehydration. Skim milk powder (SMP) and stage one infant formulas were evaluated. Among all samples, SMP had the greatest conductivity by ERT (P < 0.05), this was confirmed by off‐line methods, that is, SMP had a higher solubility, whereas infant formulas had lower solubility. Particle counts for fines of all samples reached peak values ~450 s. Results demonstrated PAT tools offer capability for rehydration characterisation of dairy and non‐dairy powders.

Current urinalysis practices in Belgian laboratories towards the 2023 EFLM European urinalysis guideline

ABSTRACT Objectives/Background We aimed to investigate routine urinalysis practices in Belgian laboratories and verify these findings against the 2023 European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) European Urinalysis Guideline. Methods A questionnaire was developed to collect information on pre- to postanalytical aspects of urine test strip and particle analysis. The questionnaire was distributed by Sciensano to all Belgian laboratories, licensed to perform urine particle analysis. Results Sixty-six percent of the Belgian laboratories (75/113) participated. The responding laboratories served physicians in private (25%), hospital (60%) and university hospital (15%) setting. All laboratories performed test strip and particle analysis, predominantly automatically (97% and 96%, respectively). In addition, most laboratories (87%) used intelligent verification criteria to optimize diagnostic accuracy. Almost all laboratories (≥90%) screened and reported a minimal biochemistry panel (glucose, protein, pH, ketones) and particle count (red and white blood cells). Independent of the technology, a notable variability was observed regarding medical cut-off values and advanced particle differentiation and reporting. Internal quality control was extensively performed for urine test strip (91%) and particle analysis (96%), while external QC was less common (32% and 36%, respectively). Consequently, only few laboratories were ISO15189 accredited for urine test strip (15%) and particle analysis (17%). Conclusion There is considerable variability in current urinalysis performed in Belgian laboratories. The 2023 EFLM urinalysis guideline has the potential to guide clinical laboratories towards improving their urinalysis practices. Additional efforts are required to implement these recommendations into clinical practice in Belgium.

The investigation of traceable preparation technique of submicron particle number concentration standards in liquids

The concentration of particles at the nano- and submicron-meter scale in liquid is crucial in multiple fields including the biomedical and semiconductor industry. However, there is still a lack of metrological standards or Certified Reference Materials (CRMs) for liquid-borne particle number concentration (PNC) which could be traceable to the International System of Units (SI). To address this issue, a quantitative and value-traceable preparation technique for liquid-borne particle number concentration CRMs (PNC-CRMs) in a submicron-meter scale based on controllable aerosol generation and collection was developed in this study. In this technique, by using commercial differential electrostatic mobility analyzer (DMA) and calibrated condensation particle counter (CPC), monodisperse aerosol particle with known concentration was initially generated. Then for quantitatively transforming the aerosol particles to the liquid, an aerosol particle collection system was designed and developed by hydrodynamic (CFD) simulations and experiment conducting, and crucial parameters of the collection system, e.g. the nozzle diameter of the aerosol particle outlet, the distance from the nozzle to the liquid surface, and the state of the liquid interface, were investigated and optimized. Under the optimized collected parameters, the collection efficiency for aerosol particles of the newly-developed system could reach over 90%. Because the PNC in aerosol is SI-traceable, combined with the obtained collection efficiency and collection time, the PNC in the collection liquid with could be obtained finally and trace to SI unit. Using this technique, two kinds of PNC-CRMs with nominal sizes of 100 and 500 nm were developed successfully, where, certified values were (7–9) × 106 particles/mL and 1.7 × 106 particles/mL, and standard uncertainties are 4.2%.

Mitigating SSIs: focus on physical operation rooms environmental factors

Background: Surgical site infections (SSIs) are associated with increased morbidity, monetary loss and mortality. The physical aspects of the operation room (OR) including airflow, humidity, pressure, and particulate counts are essential part of SSI prevention. Humidity control is vital to avoid static electricity buildup.Temperature control helps prevent hypothermia. Limiting OR traffic and door opening are essential to prevent airflow disturbance and minimze particles in OR environment. We have recently studied electronic monitoring of OR traffic and the traffic was higher than what was expected. Our aim was to evaluate our real-life measurement of these OR parameters as part of SSI prevention bundle. Methods: This is a prospective study focused on the OR physical environmental factors as part of operative SSI prevention bundle. The study was conducted for 4 weeks at an academic medical center. The study was conducted in two different generations of OR for neurosurgical and ophthalmologic procedures. We performed direct observation of OR traffic as well as environmental parameters (temperature, humidity, pressure, and particulate count) for the entire length of the procedure. We used both directly measured data as well as automated data generated by facilities. Results: The study showed that temperature, humidity, and pressure wer tightly controlled in the OR. This observation was consistent between manual data and automatically generated data. The OR traffic was not easily monitored by the current automatic data and was measured by direct observation. The correlations between particulate count and OR traffic was strongest for 0.3μm (0.7370, and weakest for 1.0μm ( 0.087). The 5.0μm particulate size had a moderate positive correlation of 0.344, Additionally, shorter procedures had less particulate matter in the OR environment. Automated data were only available in the new ORs but could not predict traffic without automated door monitors. But the automated data could easily portray the temperature, humidity and pressure minute by minute. Conclusion: OR traffic increases the particle count particularly the small size. Other physical aspects of the OR environment were tightly controlled. The ability to automatically monitor OR parameters could be extremely helpful for assuring patient safety as well as reviewing OR factors in SSI cases.

Novel method for the continuous mass concentration measurement of ultrafine particles (PM 0.1 ) with a water-based condensation particle counter (CPC)

Novel method for the continuous mass concentration measurement of ultrafine particles (PM _0.1 ) with a water-based condensation particle counter (CPC)

Absence of microplastic bioaccumulation in cod fillets from plastic-polluted western Norwegian waters

Plastics are synthetic, persistent materials that are distributed worldwide. An important concern is whether microplastics (MP) can bioaccumulate in the food chain and pose a threat to human consumers. We studied MP in the fillet of resident coastal cod from a plastic-polluted area in Western Norway, where long-range transported marine litter accumulates and MP are generated on shore. We dissected the fish and processed the samples in an MP-free lab using gentle enzymatic treatment. Micro Fourier transform infrared spectroscopy (µFTIR) was used for identification of particles down to 10 µm. The fish were 40 to 74 cm, corresponding to 2-6 years old. 29 particles were observed in fillets from eight of the 23 individuals. The mean particle count was 1.55 ± 2.75 nMP/100 g, and the mean concentration was 2.81 ± 8.33 µg/kg wet weight. Six polymer groups were identified, where polypropylene (33%) and polyethylene (30%) were the most frequent. The majority (86%) of the particles were fragments ranging from 32-100 µm. Fibers and fragments over 200 µm were observed. The largest particle was a PP particle of 258.2 µm. Controls showed minimal contamination and the procedural blanks were negative. There was no significant correlation between age, body condition, time of capture, and MP concentrations, and no evidence of bioaccumulation of MP in the fillet of older fish after in situ exposure. MP in food is of concern for human consumption and emphasizes the importance of understanding MP distribution and fate as well as reducing and controlling plastic release into the environment.

In Situ Lung Dust Analysis by Automated Field Emission Scanning Electron Microscopy With Energy Dispersive X-ray Spectroscopy: A Method for Assessing Inorganic Particles in Lung Tissue From Coal Miners.

Overexposure to respirable coal mine dust can cause severe lung disease including progressive massive fibrosis (PMF). Field emission scanning electron microscopy with energy dispersive x-ray spectroscopy (FESEM-EDS) has been used for in situ lung dust particle analysis for evaluation of disease etiology. Automating such work can reduce time, costs, and user bias. To develop and test an automated FESEM-EDS method for in situ analysis of inorganic particles in coal miner lung tissue. We programmed an automated FESEM-EDS procedure to collect particle size and elemental data, using lung tissue from 10 underground coal miners with PMF and 4 control cases. A statistical clustering approach was used to establish classification criteria based on particle chemistry. Data were correlated to PMF/non-PMF areas of the tissue, using corresponding brightfield microscopy images. Results for each miner case were compared with a separate corresponding analysis of particles recovered following tissue digestion. In situ analysis of miner tissues showed higher particle number densities than controls and densities were generally higher in PMF than non-PMF areas. Particle counts were typically dominated by aluminum silicates with varying percentages of silica. Compared to digestion results for the miner tissues, in situ results indicated lower density of particles (number per tissue volume), larger size, and a lower ratio of silica to total silicates-probably due to frequent particle clustering in situ. Automated FESEM-EDS analysis of lung dust is feasible in situ and could be applied to a larger set of mineral dust-exposed lung tissues to investigate specific histologic features of PMF and other dust-related occupational diseases.

Mitigating Cobalt Phthalocyanine Aggregation in Electrocatalyst Films through Codeposition with an Axially Coordinating Polymer.

Cobalt phthalocyanine (CoPc) is a promising molecular catalyst for aqueous electroreduction of CO2, but its catalytic activity is limited by aggregation at high loadings. Codeposition of CoPc onto electrode surfaces with the coordinating polymer poly(4-vinylpyridine) (P4VP) mitigates aggregation in addition to providing other catalytic enhancements. Transmission and diffuse reflectance UV-vis measurements demonstrate that a combination of axial coordination and π-stacking effects from pyridyl moieties in P4VPserve to disperse cobalt phthalocyanine in deposition solutions and help prevent reaggregation in deposited films. Polymers lacking axial coordination, such as Nafion, are significantly less effective at cobalt phthalocyanine dispersion in both the deposition solution and in the deposited films. SEM images corroborate these findings through particle counts and morphological analysis. Electrochemical measurements show that CoPc codeposited with P4VPonto carbon electrode surfaces reduces CO2 with higher activity and selectivity compared to the catalyst codeposited with Nafion.

Longitudinal Analysis of Annual PM2.5 Concentration Variations in Blantyre City, Malawi

This study presents current levels of fine particulate matter, with aerodynamic diameter of less than 2.5 micrometre (PM2.5) in the city of Blantyre, Malawi measured between June 2021 to May 2022. PM2.5 measurements were done in 18 different locations (spanning greater than 2 km apart) using Dylos DC1100 PRO Laser Particle Counter (2018 model). The sampling points were; 3 school campuses, 3 hospitals, 3 industrial areas, 3 open markets, 3 residential areas, and 3 commercial/ business centres (CBC) of Blantyre. PM2.5 monitoring was conducted between 10:00-12:00 hours and 15:00-17:00 hours local time. The results showed that the hourly mean PM2.5 concentrations (µg/m3) for the 10:00-12:00 time period were; 43 ± 23 µg/m3 for school campuses, 35 ± 16 µg/m3 for hospitals, 62 ± 38 µg/m3 for industrial areas, 44 ± 26 µg/m3 for markets, 40 ± 21 µg/m3 for residential areas and 35 ± 16 µg/m3 for CBC. The results showed that the hourly mean PM2.5 concentrations (µg/m3) for the 15:00-17:00 time period were; 38 ± 22 µg/m3 for school campuses, 34 ± 18 µg/m3 for hospitals, 57 ± 37 µg/m3 for industrial areas, 42 ± 25 µg/m3 for markets, 36 ± 23 µg/m3 for residential areas and 34 ± 18 µg/m3 for CBC. Significant increases of PM2.5 levels were observed in school campuses, residential areas and CBC during the months of June-October, which are windy and drier. On the other hand, lowest concentration of PM2.5 was observed during the warm season (November-March) across the sampling locations over Blantyre. Based on these findings, this study recommends further investigation of long-term concentration of PM2.5 in Blantyre city because it is hazardous and likely to cause health implications to the local population. Furthermore, interventions should be sought to reduce PM2.5 concentration in the city.

An Alternative Microbiological Validation for an Online Water Bioburden Analyzer.

The Mettler-Toledo 7000RMS analyzer is a Bio-Fluorescent Particle Counter (BFPC) used to monitor real-time bioburden results from Purified Water (PW). Validation of the analyzer using 13 microorganisms and a low-intensity, fluorescent, polystyrene bead. During the execution of the validation, a laboratory water system that met Purified Water (PW) quality standards was connected to the 7000RMS, and a syringe pump was used to introduce various concentrations of microorganisms and fluorescent polystyrene beads to the analyzer. Samples were collected and tested via the traditional Membrane Filtration (MF) method and the Colony Forming Unit (CFU) plate count results were compared to the Auto-Fluorescent Unit (AFU) of the 7000RMS analyzer. The validation study was designed to follow the guidance in United States Pharmacopeia (USP) Chapter <1223 > (1), European Pharmacopeia (EP) Chapter 5.1.6 (2), PDA Technical Report 33 (3). Concepts and strategies were adapted from EP Chapter 2.6.12 Microbiological Examination of Non-sterile Products: Microbial Enumeration Tests, EP 10.2 (4), European Pharmacopeia Chapter 2.6.1 Sterility, EP 10.2 (5), USP Chapter <61> Microbiological Examination of Non-sterile Products: Microbial Enumeration Tests (6), USP Chapter <71> Sterility Tests (7), Japanese Pharmacopoeia (JP) General Information Chapter G8 Water: Quality Control of Water for Pharmaceutical Use (8). All pre-determined validation acceptance criteria for Accuracy, Specificity, Precision, Limit of Detection (LOD), Limit of Quantitation (LOQ), Linearity, and Range were met. Further, the 7000RMS demonstrated Performance Equivalence to the MF method per USP <1223> but characteristically lacked correlation to the CFU. This validation approach highlights the superior capabilities of the 7000RMS when compared against the traditional compendial MF testing method for PW.

Operating Room Airborne Microbial Load: Nonscrubbed Staff Apparel Matters

BackgroundInfection is a leading cause of total joint arthroplasty failure. In previous studies, we found correlations between the level of contamination, concentrations of airborne particles, and the number of staff present. In this study, we focused on the apparel of nonscrubbed operating room (OR) staff to elucidate their contribution to the airborne microbial load. MethodsWe compared hospital-laundered scrubs to disposable coveralls using 2 methods. (1) Participants entered an isolation chamber with a controlled environment and completed tasks for 1 hour wearing both the approved and alternative OR attire. Settle plates collected viable contaminants that were shed by the participants during testing. (2) Lab members conducted standardized maneuvers in a functional OR that simulated typical movements of the nurse, anesthesiologist, implant representative, and entering/exiting staff. An airborne particle counter and settle plates were positioned throughout the OR. After 1 hour, the staff changed apparel and repeated the test. Each session of both phases consisted of 2 tests by the same individuals on the same day. ResultsThere was approximately a 10-fold difference in the settlement rate of viable particles between groups when employing the isolation chamber. The settle rate for scrubs was 5,519 ± 1,381 colony forming units (CFUs)/m2/h, while the settle rate for coveralls was 505 ± 55 CFUs/m2/h (P = .008). During testing in the OR, 218.7 ± 35 CFUs/m2/h were captured for scrubs, compared with 50.5 ± 13 CFUs/m2/h for the coverall (P < .01). The concentration of airborne particles collected for scrubs was 4,952.1 ± 495 particles/m3 and 1,065 ± 53 particles/m3 for the coveralls (P < .01). This was a 77% and 79% reduction for both measures, respectively. ConclusionsThe open nature of standard scrubs allows contaminated particles to escape into the OR environment, whereas the one-piece design of the coveralls restricts pathways of escape. The results of this study may be helpful when developing hospital infection prevention policies.

Multi-disciplinary optimization of single-stage hybrid rockets for lunar ascent

This study aims to determine the optimal design and ascent trajectory for a single-stage hybrid rocket in the context of a lunar ascent mission, with the objective of reaching a 100 km circular orbit on the Moon equatorial plane. A multi-disciplinary optimization problem is formulated, integrating flight design variables and launch vehicle design variables to achieve the best mission scenario. A zero-dimensional internal ballistics model is employed to estimate key parameters such as thrust, mass flow rate, and gross mass of the hybrid rocket, while a three-degree of freedom dynamical model is utilized to simulate the ascent trajectory. The resulting integrated optimization problem is solved using an in-house heuristic algorithm that combines particle swarm and genetic algorithms. Two propellant combinations, liquid oxygen/paraffin-wax and hydrogen peroxide (90%)/high-density polyethylene, are evaluated, considering both their performance in the integrated system and the feasibility of the proposed mission. After conducting a sensitivity analysis to investigate the influence of particle count in the optimization process, results for both propellant combinations are presented. While paraffin and oxygen provide the highest payload ratio, hydrogen peroxide and polyethylene entail a more feasible and flexible design for a lunar mission.

Click chemical ligation-enabled digital particle counting for multiplexed microRNA analysis

Digital counting assays, that quantify targets by counting individual signal entities, provide a promising way for the sensitive analysis of biomarkers even at the single-molecule level. Considering the requirements of complex enzyme-catalyzed amplification techniques and specialized instruments in traditional digital counting biosensors, herein, a simple digital counting platform for microRNA (miRNA) analysis is developed by employing the miRNA-templated click chemical ligation to hinge ultrabright quantum dot-doped nanoparticles (QDNPs) on the bottom of microplate well. Compared with the traditional short miRNA-mediated sandwich hybridization mechanism, the click chemistry-mediated ligation featured enhanced stability, achieving higher sensitivity by directly counting the number of QDNPs with a common wide-field fluorescence microscope. Furthermore, enzyme-free cycling click ligation strategy is adopted to push the detection limit of miRNA down to a low level of 8 fM. What is more, taking advantages of the tunable emission wavelength and narrow emission spectra of fluorescent nanoparticles, the platform enables simultaneous detection of multiplex miRNA targets without cross interference. Benefiting from the simple operation, high sensitivity, and good generality, miRNA analysis in complex samples is successfully achieved. This method not only pioneers a new route for digital counting assays but also holds great potential in miRNA-related biological researches.

Characterization of aerosol and its oxidative potential in a coastal semi-rural site of Southern Italy

Considering the scarce number of studies investigating the oxidative potential of PM2.5 in Italy, a measurement campaign was conducted from February 2020 to October 2020 in a coastal semi-rural site of Basilicata (Southern Italy) with the goal to characterize the fine fraction of ambient particulate matter (PM) and investigate its chemical and toxicological properties, by means of oxidative potential. Different instruments such as an automatic low-volume sampler, an aethalometer and an optical particle counter, were employed for the measurement of PM2.5 mass concentration, equivalent black carbon (eBC) concentration and absorption Ångström exponent (AAE), and particle number size distribution in 0.25–31 μm size range, respectively. 108 daily PM samples, collected on quartz fibre filters, were chemically analysed. Organic (OC) and elemental (EC) carbon content was estimated by thermo-optical transmittance technique (TOT), the concentrations of the main water-soluble ions and total elements were determined by ion chromatography and ED-XRF technique, while the oxidative potential of the water-soluble fraction was estimated through the dithiothreitol (DTT) assay. The mean value of PM2.5 mass concentration was 9.2 ± 2.5 μg/m3 and the average contribution of measured species on PM2.5 mass was 3.3% EC; 19.3% OC; 27.0% secondary inorganic aerosol (sum of SO42−, NH4+ and NO3−), and 10.2% of the other ions and elements. The OC and EC contributions to PM2.5 mass and their mean ratio (OC/EC = 6.6 ± 3.1) suggest that the site is affected by the combined contribution of traffic emissions and biomass combustion (domestic heating and agricultural activities), with the latter prevailing over the traffic, as supported by the mean AAE value of 1.3. The mean OP normalized by sampled volume, OPDTTV, was as high as 0.34 ± 0.22 nmol/min·m3, a value comparable to those recorded for PM2.5 in suburban areas of Italy. The correlation between OPDTTV and the chemical species observed in the PM2.5 samples showed a good agreement with the carbonaceous component OC (r = 0.62) and with some ions, K+ and SO42− (r = 0.60). These results identify combustion sources as the most responsible for the relatively high OPDTTV activity of PM2.5 recorded in this area.

Parallel Analysis of Exosomes and Cytokines in Aqueous Humor Samples to Evaluate Biomarkers for Glaucoma.

Recent emerging studies have demonstrated numerous critical roles of exosomes in cell-to-cell signaling. We investigated exosomes in the aqueous humor of glaucoma patients and controls and compared their characteristics with other biomarkers such as cytokines. Glaucoma patients exhibited higher exosome particle counts and smaller sizes compared to controls. Higher exosome density was correlated with more severe visual field loss. Conversely, concentrations of aqueous humor cytokines, particularly PD-L1, were primarily associated with intraocular pressure, and none of the cytokines showed a significant association with visual field damage. This may reflect the characteristics of exosomes, which are advantageous for crossing various biological barriers. Exosomes may contain more information about glaucoma functional damage occurring in the retina or optic nerve head. This highlights the potential importance of exosomes as signaling mediators distinct from other existing molecules.

Direct measurements of sea spray particle fluxes using a high temporal resolution optical particle counter over the coastal ocean

ABSTRACT Sea spray particles play a key role in transferring momentum, heat, and gas across the atmosphere–ocean interface at high wind speeds and represent an important source of cloud condensation nuclei which affect the genesis, chemistry, and radiative properties of marine clouds. Here, we present direct measurements of sea spray particle fluxes obtained using an eddy covariance technique through the use of a newly developed high temporal resolution optical particle counter. With this instrumentation measurements were made over the coastal ocean during a 5-week field campaign conducted at an observation pier from November to December 2021. Our optical particle counter was capable of measuring size spectra at a rate of 10 Hz in 8 channels covering a range of mean radii between 0.3 and 15. The power spectra of particle number density followed the Kolmogorov −2/3 power law. The shape of the cospectrum of the particle number density flux was basically similar to that of the cospectra of the heat and gas fluxes. The measured sea spray particle fluxes at mean wind speeds of up to 21 m s−1 were dominated by an upward flux, which likely represents aerosol production caused by the bursting of bubbles at the ocean surface.

Three-dimensional characterization of particle size, shape, and internal porosity for Apollo 11 and Apollo 14 lunar regolith and JSC-1A lunar regolith soil simulant

Samples of soils collected by the Apollo 11 mission (10084,2036) and the Apollo 14 mission (14163,940) were obtained from the NASA Curation and Analysis Planning Team for Extraterrestrial Materials (CAPTEM) program. The particle size, shape, and internal porosity were characterized in three dimensions (3D) using a combination of X-ray computed tomography (XCT) and mathematical analysis, with various size and shape parameters measured and calculated for each particle. High-resolution scanning electron microscopy (SEM) was used to image the particles that were too small for the two XCT instruments used. Similar characterization was carried out on samples of JSC-1A lunar soil simulant, updating a previous analysis. Approximately 14,000 lunar regolith particles and 128,000 JSC1-A particles, covering a wide range of size and shape, were characterized for this paper and the results stored in a publicly accessible database. This large number of particles enabled, for the first time, statistically valid particle shape distributions to be generated. The 3D shape distributions of the two regoliths and JSC-1A were quantitatively compared and it was found that the way particle shape and porosity depends on particle size was different between regolith and simulant. The measured size distribution of particles in the lunar soils was applied to estimate the relative contributions of different sizes to the ensemble average particle single scattering albedo and phase function. By linking our particle counts to published sieve weight fractions for the lunar samples, we find that ∼80% of the total cross-section area is contributed by particles <20 μm diameter and ∼ 50% by particles <8 μm diameter. The orientation-averaged two-dimensional projected areas of the actual regolith particles were computed so that this estimate was also based on real particle shapes. Such small sizes dominating the total cross-section area suggest that calculations of the elements of the scattering matrix for individual particles may be possible with modest computing capabilities leading to the development of improved models for the quantitative interpretation of remote sensing spectrophotometry and polarimetry. This 3D characterization and database will enable other computational work to be done with real lunar regolith particle shapes, including discrete element method mechanical modeling, packing simulations, further light scattering calculations, dust contamination modeling, and modeling of lunar rover interactions with collected and packed regolith particles.

Examination of Particulate Contamination in Parenteral Injections and Infusions Following Fluid Withdrawal Utilizing Conventional Needles and Filter Needles: Assessment of Compliance and Comparative Analysis

Particulate contamination, the unintentional presence of particles in parenteral fluids, is associated with potential risks such as phlebitis and thrombophlebitis. Recent guidelines recommend the use of filter needles when withdrawing parenteral fluid from vials with a rubber stopper. However, the literature is limited and lacks clarity regarding the advantages of filter needles over conventional needles. The aim of this study was to assess the compliance of parenteral fluids regarding particulate contamination after withdrawing fluid using both conventional needles and filter needles, following the guidelines of European Pharmacopoeia (Ph. Eur.) and United States Pharmacopoeia (USP). Visible particles were counted through visual inspection and sub-visible particles were quantified utilizing the light obscuration particle count test. Particle counts for both types of needles were compared to Ph. Eur. and USP standards and differences in particle contamination were assessed using a Mann-Whitney U test. Both types of needles demonstrated compliance with Ph. Eur. and USP standards regarding particulate contamination of visible and sub-visible particles. However, filter needles exhibited a significantly higher particle count for particles with a size of ≥25 µm compared to conventional needles (p = 0.0029). In conclusion, both types of needles demonstrate suitability for aspirating fluid from vials featuring rubber stoppers regarding particulate contamination. Nevertheless, non-filter needles are preferred for withdrawing fluid from vials with a rubber stopper over filter needles due to their lower cost.

Comparison of scanning aerosol lidar and in situ measurements of aerosol physical properties and boundary layer heights

Abstract. The spatiotemporal distribution of aerosol particles in the atmosphere has a great impact on radiative transfer, clouds, and air quality. Modern remote sensing methods, as well as airborne in situ measurements by unpiloted aerial vehicles (UAV) or balloons, are suitable tools to improve our understanding of the role of aerosol particles in the atmosphere. To validate the measurement capabilities of three relatively new measurement systems and to bridge the gaps that are often encountered between remote sensing and in situ observation, as well as to investigate aerosol particles in and above the boundary layer, we conducted two measurement campaigns and collected a comprehensive dataset employing a scanning aerosol lidar, a balloon-borne radiosonde with the Compact Optical Backscatter Aerosol Detector (COBALD), an optical particle counter (OPC) on a UAV, and a comprehensive set of ground-based instruments. The extinction coefficients calculated from near-ground-level aerosol size distributions measured in situ are well correlated with those retrieved from lidar measurements, with a slope of 1.037 ± 0.015 and a Pearson correlation coefficient of 0.878, respectively. Vertical profiles measured by an OPC-N3 on a UAV show similar vertical particle distributions and boundary layer heights to lidar measurements. However, the sensor, OPC-N3, shows a larger variability in the aerosol backscatter coefficient measurements, with a Pearson correlation coefficient of only 0.241. In contrast, the COBALD data from a balloon flight are well correlated with lidar-derived backscatter data from the near-ground level up to the stratosphere, with a slope of 1.063 ± 0.016 and a Pearson correlation coefficient of 0.925, respectively. This consistency between lidar and COBALD data reflects the good data quality of both methods and proves that lidar can provide reliable and spatial distributions of aerosol particles with high spatial and temporal resolutions. This study shows that the scanning lidar has the capability to retrieve backscatter coefficients near the ground level (from 25 to 50 m above ground level) when it conducts horizontal measurement, which is not possible for vertically pointing lidar. These near-ground-level retrievals compare well with ground-level in situ measurements. In addition, in situ measurements on the balloon and UAV validated the scanning lidar retrievals within and above the boundary layer. The scanning aerosol lidar allows us to measure aerosol particle distributions and profiles from the ground level to the stratosphere with an accuracy equal to or better than in situ measurements and with a similar spatial resolution.

The EFLM European Urinalysis Guideline 2023.

The EFLM Task and Finish Group Urinalysis has updated the ECLM European Urinalysis Guidelines (2000) on urinalysis and urine bacterial culture, to improve accuracy of these examinations in European clinical laboratories, and to support diagnostic industry to develop new technologies. Graded recommendations were built in the following areas. Strategies of urine testing are described to patients with complicated or uncomplicated urinary tract infection (UTI), and high or low-risk to kidney disease. Patient preparation, and urine collection are supported with two quality indicators: contamination rate (cultures), and density of urine (chemistry, particles). Measurements of both urine albumin and α1-microglobulin are recommended for sensitive detection of kidney disease in high-risk patients. Performance specifications are given for urine protein measurements and quality control of multiproperty strip tests. Procedures for microscopy are reviewed for diagnostic urine particles, including urine bacteria. Technologies in automated particle counting and visual microscopy are updated with advice how to verify new instruments with the reference microscopy. Chromogenic agar is recommended as primary medium in urine cultures. Limits of significant growth are reviewed, with an optimised workflow for routine specimens, using leukocyturia to reduce less important antimicrobial susceptibility testing. Automation in bacteriology is encouraged to shorten turn-around times. Matrix assisted laser desorption ionization time-of-flight mass spectrometry is applicable for rapid identification of uropathogens. Aerococcus urinae, A. sanguinicola and Actinotignum schaalii are taken into the list of uropathogens. A reference examination procedure was developed for urine bacterial cultures.