Particulate Components Research Articles

Polarization Characterization of Porous Particles Based on DDA Simulation and Multi-Angle Polarization Measurements.

Porous suspended particles are hazardous to human health due to their strong absorption capacity for toxic substances. A fast, accurate, in situ and high-throughput method to characterize the microporous structure of porous particles has extensive application value. The polarization changes during the light scattering of aerosol particles are highly sensitive to their microstructural properties, such as pore size and porosity. In this study, we propose an overlapping sphere model based on the discrete dipole approximation (DDA) to calculate the polarization scattering characteristics of porous particles. By combining scattering calculations with multi-dimensional polarization indexes measured by a multi-angle polarized scattering vector detection system, we achieve the identification and classification of pore-type components in suspended particles. The maximum deviation based on multiple indexes is less than 0.16% for the proportion analysis of mixed particles. Simultaneously, we develop a quantitative inversion algorithm on pore size and porosity. The inversion results of the three porous polymer particles support the validity and feasibility of our method, where the inversion error of partial particles is less than 4% for pore size and less than 6% for porosity. The study demonstrates the potential of polarization measurements and index systems applied in characterizing the micropore structure of suspended particles.

Analysis of the amount and structure of solid particles PM released into the city’s atmospheric air by motor transport

Atmospheric air pollution with fine particles PM2.5 and PM10 is one of the main environmental problems of the city. This paper presents the results of the study of quantitative and structural components of solid particles’ emissions in the city of Almaty, released during the operation of cars: by an engine with exhaust gases, by tire abrasion, by braking devices (linings) and road pavement wear. РM solid particles in the amount of 543.2 tons are released annually into the atmospheric air of Almaty by motor transport. The bulk PM10 is released totally from the tires, brakes and road – 65.4 %, from the engine – 34.6 %. On diesel buses and trucks, the bulk РM particles’ emissions are released from the exhaust gas engines. Recommendations are given to reduce PM particles emitted by motor transport.

DEMNUni: cross-correlating the nonlinear ISWRS effect with CMB-lensing and galaxies in the presence of massive neutrinos

We present an analytical modelling of the angular cross-correlations between the Integrated Sachs Wolfe-Rees Sciama (ISWRS) effect and large-scale structure tracers in the presence of massive neutrinos. Our method has been validated against large N-body simulations with a massive neutrino particle component, namely the DEMNUni suite. We investigate the impact of different neutrino masses on the cross-correlations between the ISWRS effect and both the galaxy clustering and the lensing of the Cosmic Microwave Background (CMB). We also test the ability of current nonlinear matter power spectrum modellings to reproduce neutrino effects in such cross-correlations. We show that the multipole position of a characteristic sign inversion in the cross-spectra, due to nonlinear effects, is strongly related to the total neutrino mass Mν and depends almost linearly on it. While these nonlinear cross-correlation signals may not be able alone to constrain the neutrino mass, our approach paves the way to the detection of such cross-spectra on small scales for their exploitation in combination with main probes from future galaxy surveys and CMB experiments.

Characteristics of number concentration, size distribution and components of particulate matter emitted from a typical large civil airport

Civil airports are recognized as significant contributors to fine particulate matter, especially ultra-fine particulate matter (UFP). The pollutants from airport activities have a notable adverse impact on global climate, urban air quality, and public health. However, there is a lack of practical observational studies on the characterization of integrated pollutant emissions from large civil airports. This study aims to focus on the combined emission characteristics of particulate number concentration (PNC), size distribution, and components at a large civil airport, especially UFP. The findings reveal that airport activities significantly contribute to elevated PNC levels during aircraft activity in downwind conditions (four times higher than background levels) and upwind conditions (7.5 times higher). UFP dominates the PNC around the airport. The particle size distribution shows two peaks occurring around 10-30 nm and 60-80 nm. Notably, particles within the ranges of 17-29 nm and 57-101 nm account for 65.9 % and 12.0 % of the total PNC respectively. Aircraft landing has the greatest impact on particles sized between 6 and 17 nm while takeoff affects particles sized between 29 and 57 nm resulting in a respective increase in PNC by factors of approximately 3.27 and 35.4-fold increase compared to background levels. Different aircraft types exhibit varying effects on PNC with A320 and A321 showing more pronounced effects during takeoff and landing.The presence of airports leads to roughly five-fold rise in elemental component concentrations with Si being highest followed by OC, Ca, Al, Fe, Ca2+, EC, and Mg2+. The OC/EC ratio under high aircraft activity in downwind conditions falls within range of approximately 2.5–3.5. These characteristic components and ratio can be considered as identifying species for civil airports. PMF model show about 75 % of the particulate emissions at the airport boundary were related to airport activities.

Mechanism study of aging oil demulsification and dehydration under ultrasonic irradiation

With the tertiary oil recovery in the oilfield, the content of aging oil emulsion with high water content and complex components has become more prevalent, so it is crucial for aging oil to break the emulsification. In this paper, the experimental laws of water content are explored under the conditions of different transducer input powers through the ultrasonic reforming of aging oil, and the microscopic topography, particle size, components, etc. of oil samples before and after the irradiation of ultrasound are characterized through the microscopic analysis, particle size analysis and component analysis and other ways. The results show that the oil samples achieve the effect of demulsification and dehydration in the presence of ultrasonic cavitation effect, with a maximum dehydration rate of 98.24 %, and that the dehydration rate follows an “M−type” trend with the increase of power. The results of microscopic and particle size analyses demonstrate that ultrasonic irradiation destabilizes the oil–water interfacial membrane, and causes droplets of different sizes to collide, agglomerate, and settle. It was also observed that the droplets of the emulsion system are more evenly distributed and the intervals are increased. Furthermore, we hypothesize that ultrasound may be less irreversible in demulsification and dehydration of aging oil.

N-terminal modification of an LAH4-derived peptide increases mRNA delivery in the presence of serum.

The recently developed mRNA-based coronavirus SARS-CoV-2 vaccines highlighted the great therapeutic potential of the mRNA technology. Although the lipid nanoparticles used for the delivery of the mRNA are very efficient, they showed, in some cases, the induction of side effects as well as the production of antibodies directed against particle components. Thus, the development of alternative delivery systems is of great interest in the pursuit of more effective mRNA treatments. In the present work, we evaluated the mRNA transfection capacities of a series of cationic histidine-rich amphipathic peptides derived from LAH4. We found that while the LAH4-A1 peptide was an efficient carrier for mRNA, its activity was highly serum sensitive. Interestingly, modification of this cell penetrating peptide at the N-terminus with two tyrosines or with salicylic acid allowed to confer serum resistance to the carrier.

Functions of extracellular polymeric substances in partitioning suspended and sinking particles in the upper oceans of two open ocean systems

AbstractMarine particle dynamics and carbon export, involving extracellular polymeric substances (EPS) like transparent exopolymer particles (TEP) and Coomassie Brilliant Blue‐stained particles (CSP), are poorly understood. Although TEP adhesive properties may enhance carbon export by facilitating aggregate formation, their low density can also enhance particle suspension. Factors influencing TEP regulation of particle dynamics remain unclear. To investigate EPS contributions to particle dynamics, we investigated ratios of TEP to particulate organic carbon (POC) and of CSP to POC in suspended and sinking particles collected with marine snow catchers. Samples were collected in a subarctic region near Hokkaido during a spring phytoplankton bloom and in the oligotrophic, subtropical Kuroshio region. At Hokkaido, the mean TEP : POC ratio of sinking particles (0.075 μg Xeq. : μg C) was > 30× lower than in suspended particles (2.3), consistent with a model prediction of selective retention of buoyant TEP‐rich particles in the upper water column. In the Kuroshio region, sinking particles also contained fewer TEP than suspended particles; however, the TEP : POC ratio of sinking particles (1.0) was > 10× higher than at Hokkaido, suggesting that TEP constitute a significant carbon component of sinking particles. These findings indicate that TEP facilitate aggregation of high‐density particles and particle sinking in the Kuroshio region. Distributions of CSP : POC ratios between suspended and sinking particles resembled TEP : POC ratios in both regions, implying a significant contribution of CSP to particle dynamics. We propose that EPS have divergent effects on suspension and sinking of marine particles, which vary with particle composition and biogeochemical conditions.

The affinity of milk fat globule membrane fragments and buttermilk proteins to hydroxyapatite

Buttermilk differs from skim milk by the presence of milk fat globule membrane (MFGM) fragments that are released during cream churning. MFGM is rich in health-promoting components, such as phospholipids and membrane proteins, but these compounds have a negative impact on buttermilk techno-functional properties in dairy applications. The isolation of MFGM from buttermilk improved its functionality while also recovering the MFGM bioactive components. Hydroxyapatite (HA) can be used to extract MFGM by adsorption via charged site interactions. However, the affinity of HA to MFGM or the main buttermilk proteins (casein micelles (CM), β-lactoglobulin (β-lg) and α-lactalbumin (α-lac)) is not known. The influence of important physicochemical parameters such as pH and temperature on these interactions is also unclear. For each buttermilk component, a quartz crystal microbalance diffusion analysis was performed to determine the maximum adsorption time and the attached mass density on HA-coated gold sensors. The influence of pH, ionic strength (IS), and temperature (T) on the affinity of each buttermilk component for HA particles was assessed using a 3-levels and 3-factors Box-Behnken design. The absorption rate was highest for the CM, followed by β-lg and α-lac, and then by the MFGM. Nevertheless, the final maximal attached mass densities to the HA were similar for the MFGM and CM, and 2.5 times higher than for β-lg and α-lac. This difference can be explained by the higher number of binding sites found in CM and their heavier mass. The model obtained by the Box-Behnken design plan showed that the adsorption of the CM changed with T, pH and IS. These results suggest that the techno-functional properties of buttermilk may be restored by specifically extracting MFGM with HA. Experiments are ongoing to determine conditions for fractionating MFGM directly from buttermilk.

Analysis of Trypanosoma equiperdum Recombinant Proteins for the Serological Diagnosis of Dourine.

The significance of Trypanosoma equiperdum as the causative agent of dourine cannot be understated, especially given its high mortality rate among equids. International movement of equids should be subject to thorough health checks and screenings to ensure that animals are not infected with Trypanosoma equiperdum. This involves the implementation of quarantine protocols, testing procedures, and the issuance of health certificates to certify the health status of the animals. Three proteins, the peptidyl-prolyl cis-trans isomerase (A0A1G4I8N3), the GrpE protein homolog (A0A1G4I464) and the transport protein particle (TRAPP) component, putative (A0A1G4I740) (UniProt accession numbers SCU68469.1, SCU66661.1 and SCU67727.1), were identified as unique to T. equiperdum by bioinformatics analysis. The proteins were expressed as recombinant proteins and tested using an indirect ELISA and immunoblotting test with a panel of horse positive and negative sera for dourine. The diagnostic sensitivity, specificity and accuracy of the i-ELISAs were 86.7%, 53.8% and 59.0% for A0A1G4I8N3; 53.3%, 58.7% and 57.9% for A0A1G4I464; and 73.3%, 65.0% and 66.3% for A0A1G4I740, respectively, while the diagnostic sensitivity, specificity and accuracy of immunoblotting were 86.7%, 92.5% and 91.6% for A0A1G4I8N3; 46.7%, 81.3% and 75.8% for A0A1G4I464; and 80.0%, 63.8% and 66.3% for A0A1G4I740. Among the three proteins evaluated in the present work, A0A1G4I8N3 provided the best results when tested by immunoblotting; diagnostic application of this protein should be further investigated using a greater number of positive and negative sera.

Morphological and optical properties of carbonaceous aerosol particles from ship emissions and biomass burning during a summer cruise measurement in the South China Sea

Abstract. Carbonaceous aerosols constitute a crucial component of atmospheric marine aerosols among which black carbon (BC) and brown carbon (BrC) are important contributors to light absorption and hence the positive climatic radiative forcing in the marine atmosphere. We conducted month-long (5 May–9 June 2021) onboard sample collections and online measurements of carbonaceous aerosols to characterize their morphological and optical properties during a ship cruise in the South China Sea (SCS), covering a marine region of 11.9–24.5° N, 111.1–118.2° E. Single particles were collected by a single-particle sampler, and offline analyses were performed using a transmission electron microscope (TEM) coupled with energy-dispersive X-ray spectroscopy (EDS). Online measurements of BC in PM2.5 were made by a seven-wavelength aethalometer, and organic carbon (OC) and elemental carbon (EC) mass concentrations were measured by a semi-online OC/EC analyzer. Feret diameters of the single particles during navigation and stop showed size distributions with the lognormal fitting peaks at 307 and 325 nm, respectively. The fresh (without coating) and aged BC particles (after removal of coating by the electron beams in the TEM) showed same median fractal dimensions (1.61), in contrast to their different median lacunarities (0.53 vs. 0.59). The aged BC particles showed narrower Feret diameters (229–2557 nm) during navigation than those (78–2926 nm) of freshly emitted BC from the ship's own exhaust during stop. Moreover, tar balls, as one important component of single particles from ship emissions and as the tracer of biomass burning, were identified with geometrical diameters of 160–420 nm in the TEM images. The EDS analyses showed those tar balls are mainly mixed with sea salt, organics, BC, and sulfate. We also found a significant fraction of aged BC in various mixing states (core–shell, embedded) with other components of the aerosol particles after long-range transport. The campaign was further divided into several periods (the before-monsoon period, BMP; transition monsoon period, TMP; after-monsoon period, AMP; and ship pollution period, SPP) according to the wind direction during monsoon and the ship's own pollution. The median absorption Ångström exponent (AAE) values derived from all wavelengths were 1.14, 1.02, 1.08, and 1.06 for BMP, TMP, AMP, and SPP, respectively. Particularly, a median AAE value of 1.93 was obtained during two significant biomass burning events. These results showed that biomass burning (BB) and fossil fuel (FF) combustion contributed to 18 %–22 % and 78 %–82 % of all the BC light absorption without the two intense biomass burning events, during which BB and FF accounted for 42 % and 58 %, respectively. The two BB events originated from the Philippines and Southeast Asia before and after the summer monsoon. Our results demonstrated that BC can serve as the core of aged particles, but the fractal dimensions of BC aggregates were subject to little variation; moreover, such BC particles become much more aggregated after aging in the marine atmosphere, which further affects the light absorption of the BC particles in the SCS.

Epoxidized technical Kraft lignin as a particulate resin component for high-performance anticorrosive coatings

Deterioration of steel infrastructures is often caused by corrosive substances. In harsh conditions, the protection against corrosion is provided by high-performance coatings. The major challenge in this field is to find replacements for the fossil-based resins constituting anticorrosive coatings, due to increasing needs to synthesize new environmentally friendly materials. In this study, softwood Kraft lignin was epoxidized with the aim of obtaining a renewable resin for anticorrosive coatings. The reaction resulted in the formation of heterogeneous, solid, coarse agglomerates. Therefore, the synthetized lignin particles were mechanically ground and sieved to break up the agglomerates and obtain a fine powder. To reduce the use of fossil fuel-based epoxy novolac resins in commercial anticorrosive coatings, a series of formulations were prepared and cured on steel panels varying the content of epoxidized lignin resin. Epoxidized lignin-based coatings used in conjunction with conventional epoxy novolac resin demonstrated improved performance in terms of corrosion protection and adhesion properties, as measured by salt spray exposure and pull-off adhesion test, respectively. In addition, the importance of size fractionation for the homogeneity of the final coating formulations was highlighted. The findings from this study suggest a promising route to develop high-performing lignin-based anticorrosive coatings.

Quantifying Multipollutant Health Impacts Using the Environmental Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE): A Case Study in Atlanta, Georgia.

Air pollution risk assessments do not generally quantify health impacts using multipollutant risk estimates, but instead use results from single-pollutant or copollutant models. Multipollutant epidemiological models account for pollutant interactions and joint effects but can be computationally complex and data intensive. Risk estimates from multipollutant studies are therefore challenging to implement in the quantification of health impacts. Our objective was to conduct a case study using a developmental multipollutant version of the Environmental Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE) to estimate the health impact associated with changes in multiple air pollutants using both a single and multipollutant approach. BenMAP-CE was used to estimate the change in the number of pediatric asthma emergency department (ED) visits attributable to simulated changes in air pollution between 2011 and 2025 in Atlanta, Georgia, applying risk estimates from an epidemiological study that examined short-term single-pollutant and multipollutant (with and without first-order interactions) exposures. Analyses examined individual pollutants (i.e., ozone, fine particulate matter, carbon monoxide, nitrogen dioxide (), sulfur dioxide, and particulate matter components) and combinations of these pollutants meant to represent shared properties or predefined sources (i.e., oxidant gases, secondary pollutants, traffic, power plant, and criteria pollutants). Comparisons were made between multipollutant health impact functions (HIF) and the sum of single-pollutant HIFs for the individual pollutants that constitute the respective pollutant groups. Photochemical modeling predicted large decreases in most of the examined pollutant concentrations between 2011 and 2025 based on sector specific (i.e., source-based) estimates of growth and anticipated controls. Estimated number of avoided asthma ED visits attributable to any given multipollutant group were generally higher when using results from models that included interaction terms in comparison with those that did not. We estimated the greatest number of avoided pediatric asthma ED visits for pollutant groups that include (i. e., criteria pollutants, oxidants, and traffic pollutants). In models that accounted for interaction, year-round estimates for pollutant groups that included ranged from 27.1 [95% confidence interval (CI): 1.6, 52.7; traffic pollutants] to 55.4 (95% CI: 41.8, 69.0; oxidants) avoided pediatric asthma ED visits. Year-round results using multipollutant risk estimates with interaction were comparable to the sum of the single-pollutant results corresponding to most multipollutant groups [e.g., 52.9 (95% CI: 43.6, 62.2) for oxidants] but were notably lower than the sum of the single-pollutant results for some pollutant groups [e.g., 77.5 (95% CI: 66.0, 89.0) for traffic pollutants]. Performing a multipollutant health impact assessment is technically feasible but computationally complex. It requires time, resources, and detailed input parameters not commonly reported in air pollution epidemiological studies. Results estimated using the sum of single-pollutant models are comparable to those quantified using a multipollutant model. Although limited to a single study and location, assessing the trade-offs between a multipollutant and single-pollutant approach is warranted. https://doi.org/10.1289/EHP12969.

High-Level Secretory Production of Recombinant E2-Spy Antigen Protein via Combined Strategy in Pichia pastoris

E2-Spy (abbreviated as ES) plays a vital role as a component in the Bacterial-Like Particles (BLPs) vaccine against classical swine fever virus (CSFV). This vaccine demonstrates remarkable immunoprotection, highlighting the importance of augmenting ES production in the development of CSFV subunit vaccines. In this study, a Pichia pastoris strain capable of high-yield secretory production of ES was developed through signal peptide engineering, gene dosage optimization and co-expression of molecular chaperones. Initially, a hybrid signal peptide cSP3 was engineered, leading to a 3.38-fold increase in ES production when compared to the control strain 1-α-ES. Subsequently, cSP3 was evaluated for its expression efficiency alongside different commonly used signal peptides under multicopy conditions. SDS-PAGE analysis revealed that 2-αd14-ES exhibited the highest ES production, displaying a 4.38-fold increase in comparison to 1-α-ES. Afterwards, SSA1, YDJ1, BIP, LHS1, and their combinations were integrated into 2-αd14-ES, resulting in a 1.92-fold rise in ES production compared to 2-αd14-ES (equivalent to a 6.18-fold increase compared to 1-α-ES). The final yield of ES was evaluated as 168.3 mg/L through comparison with serially diluted BSA protein bands.

Quantification and Characterization of Fine Plastic Particles as Considerable Components in Atmospheric Fine Particles.

The negative effects of air pollution, especially fine particulate matter (PM2.5, particles with an aerodynamic diameter of ≤2.5 μm), on human health, climate, and ecosystems are causing significant concern. Nevertheless, little is known about the contributions of emerging pollutants such as plastic particles to PM2.5 due to the lack of continuous measurements and characterization methods for atmospheric plastic particles. Here, we investigated the levels of fine plastic particles (FPPs) in PM2.5 collected in urban Shanghai at a 2 h resolution by using a novel versatile aerosol concentration enrichment system that concentrates ambient aerosols up to 10-fold. The FPPs were analyzed offline using the combination of spectroscopic and microscopic techniques that distinguished FPPs from other carbon-containing particles. The average FPP concentrations of 5.6 μg/m3 were observed, and the ratio of FPPs to PM2.5 was 13.2% in this study. The FPP sources were closely related to anthropogenic activities, which pose a potential threat to ecosystems and human health. Given the dramatic increase in plastic production over the past 70 years, this study calls for better quantification and control of FPP pollution in the atmosphere.

Discovery and inspiration of large- and medium-sized glutenite-rich oil and gas fields in the eastern South China Sea: An example from Paleogene Enping Formation in Huizhou 26 subsag, Pearl River Mouth Basin

Based on the practice of oil and gas exploration in the Huizhou Sag of the Pearl River Mouth Basin, the geochemical indexes of source rocks were measured, the reservoir development morphology was restored, the rocks and minerals were characterized microscopically, the measured trap sealing indexes were compared, the biomarker compounds of crude oil were extracted, the genesis of condensate gas was identified, and the reservoir-forming conditions were examined. On this basis, the Paleogene Enping Formation in the Huizhou 26 subsag was systematically analyzed for the potential of oil and gas resources, the development characteristics of large-scale high-quality conglomerate reservoirs, the trapping effectiveness of faults, the hydrocarbon migration and accumulation model, and the formation conditions and exploration targets of large- and medium-sized glutenite-rich oil and gas fields. The research results were obtained in four aspects. First, the Paleogene Wenchang Formation in the Huizhou 26 subsag develops extensive and thick high-quality source rocks of semi-deep to deep lacustrine subfacies, which have typical hydrocarbon expulsion characteristics of “great oil generation in the early stage and huge gas expulsion in the late stage”, providing a sufficient material basis for hydrocarbon accumulation in the Enping Formation. Second, under the joint control of the steep slope zone and transition zone of the fault within the sag, the large-scale near-source glutenite reservoirs are highly heterogeneous, with the development scale dominated hierarchically by three factors (favorable facies zone, particle component, and microfracture). The (subaqueous) distributary channels near the fault system, with equal grains, a low mud content (<5%), and a high content of feldspar composition, are conducive to the development of sweet spot reservoirs. Third, the strike-slip pressurization trap covered by stable lake flooding mudstone is a necessary condition for oil and gas preservation, and the NE and nearly EW faults obliquely to the principal stress have the best control on traps. Fourth, the spatiotemporal configuration of high-quality source rocks, fault transport/sealing, and glutenite reservoirs controls the degree of hydrocarbon enrichment. From top to bottom, three hydrocarbon accumulation units, i.e. low-fill zone, transition zone, and high-fill zone, are recognized. The main area of the channel in the nearly pressurized source-connecting fault zone is favorable for large-scale hydrocarbon enrichment. The research results suggest a new direction for the exploration of large-scale glutenite-rich reservoirs in the Enping Formation of the Pearl River Mouth Basin, and present a major breakthrough in oil and gas exploration.

Bushfire-smoke trigger hospital admissions with cerebrovascular diseases: Evidence from 2019-20 bushfire in Australia.

Exposure to ambient air pollution is strongly associated with increased cerebrovascular diseases. The 2019-20 bushfire season in Australia burnt 5.4 million hectares of land in New South Wales alone, with smoke so severe it affected cities in Argentina, 11,000 km away. The smoke emitted by bushfires consists of both gaseous and particle components. It is important to note that exposure to particulate matter has been shown to be linked to a heightened risk of stroke, which is the primary kind of cerebrovascular illness, as well as an increased likelihood of hospitalisations and mortality. However, the available data is inadequate in terms of documenting the response of patients diagnosed with a proven cerebrovascular illness to bushfire smoke. Additionally, there is a lack of information about the health effects associated with particulate matter throughout the bushfire season and on days when smoke was present in 2019 and 2020.Therefore, we aimed to determine the effects of (i) short-term air pollution triggered by bushfires and (ii) high smoke days in increasing the daily number of hospital admissions with cerebrovascular diseases. Hospitalisation data were accessed from the admitted patient dataset from seven local Government areas of Hunter New England Local Health District. The bushfire period was defined from 1 October 2019 to 10 February 2020, and a same period from 2018-19 as the control. High bushfire smoke days were days when the average daily concentration of particulate matter was higher than the 95th percentile of the control period. Poisson regression models and fixed effect meta-analysis were used to analyse the data. In total, 275 patients with cerebrovascular admissions were identified, with 147 (53.5%) during the bushfire (2019-20) and 128 (46.5%) in the control period (2018-19). There was no significant increase in daily admissions for cerebrovascular disease (Incidence Rate Ratio, IRR: 1.04; 95% CI: 0.81-1.34; p-value: 0.73), acute stroke (IRR: 1.15; 95% CI: 0.88-1.50; p-value: 0.29) or acute ischaemic stroke (IRR: 1.18; 95% CI: 0.87-1.59; p-value: 0.28), over the entire bushfire period. However, the high bushfire smoke days were associated with increased acute ischaemic stroke-related hospital admissions across lead 0-3 and the highest cumulative effect was observed with lead 0 (IRR:1.52; 95% CI: 1.01-2.29; p-value: 0.04). In addition, during the bushfire period, particulate matter, both PM10 and PM2.5 (defined as particulates that have an effective aerodynamic diameter of 10, and 2.5 microns, respectively), were also associated with increased acute ischaemic stroke admissions with a lag of 0-3 days. The results suggested a possible association between particulate matter and high smoke days with increased hospital admissions due to acute ischaemic stroke during the recent Australian bushfire season.

Signal detection and material identification method for loose particles inside aerospace relays based on overlapping signals

Loose particle is an important factor affecting the reliability of aerospace relays. Particle Impact Noise Detection method is a commonly used loose particle detection method, but it can generate interference signals. Accurately identifying loose particle signals and component signals becomes the key to accurately detecting loose particles. Meanwhile, deeply exploring the properties of loose particle signals and further provide material information can provide guidance for manufacturing processes. However, the existing loose particle signal and component signal identification research, as well as the loose particle material identification research, has problems such as limited research objects to pure signals, independent identification results, and failure to refer to the detection requirements in real application scenarios. It is difficult to apply and its practicality is not high. Based on this, the authors proposed a signal detection and material identification method for loose particles based on overlapping signals. Specifically, referring to the latest loose particle detection information, aerospace relay samples were made, and the component identification model and material identification model based on parameter-optimized random forest were trained, respectively. They can achieve good classification effects on data sets created from pure loose particle signals, pure component signals, and pure loose particle signals corresponding to different materials, respectively. On this basis, confidence coefficient was proposed to quantify the degradation degree of the classification effects of the two models on the data set created from overlapping signals, thus the component confidence coefficient and the loose particle confidence coefficient were obtained, respectively. They can be used to determine valid pulses from pure loose particle signals, pure component signals, and mixed signals in overlapping signals, completing loose particle detection. Valid pulses from pure loose particle signals were screened for material identification. In this way, for the aerospace relay to be tested, first, the loose particle detection results can be obtained by a comprehensive judgment of the component identification model, component confidence coefficient, and loose particle confidence coefficient. Second, the material identification results can be obtained by combining the material identification model with the majority voting processing. In addition, the definition of identification accuracy applicable to the loose particle detection was proposed to meet the engineering application requirements in real application scenarios. Multiple experiments verified the feasibility, practicality, and stability of the proposed method.

Assessment of meso- and microplastics distribution in coastal sediments and waters at the middle estuary of the Rio De La Plata, Argentina (SW Atlantic Ocean)

Estuarine coastal water and sediments collected from multiple locations within the middle Río de la Plata (RDLP) estuary were analyzed in order to identify the presence of microplastics (MPs, <5 mm) and mesoplastics (MePs, 5–25 mm) in one of the most significant estuaries in the Southwestern Atlantic. The present study represents one of the first researches to survey MPs and MePs contamination in key stations at RDLP estuary. Average concentrations of 14.17 ± 5.50 MPs/L and 10.00 MePs/L were detected in water samples, while 547.83 ± 620.06 MPs/kg (dry weight) and 74.23 ± 47.29 MePs/kg d.w. were recorded in sediments. The greatest abundances were observed in the more anthropized areas, near urban settlements. Fibers were the most conspicuous plastic items in water and sediments, followed by fragments. On the other hand, surface sediments, and 50 cm and 100 cm-depth sediments also presented MPs and MePs indicating they could serve as a stratigraphic indicator for recently formed sediments. The main polymer type identified were acrylic fibers, followed by polypropylene (PP) and polyethylene terephthalate (PET). Besides, SEM-EDX detected the presence of Si, Fe, Ti, Al and Cl onto the plastics' surface. These elements may serve as additives to enhance the plastics' properties, such as in the case of Ti, or they could originate from the environment, like biogenic Si or Fe, and Al possibly as a component of the suspended particles or sediments adhered to the micro or meso plastics. Finally, the results of the present study showed that MPs and MePs are commonly found in waters and also tend to be trapped in sediments of the RDLP estuary supporting the assertion that these areas play a substantial role in influencing the transport, dispersion, and buildup of MPs in estuarine regions.

Engineering protein translocation and unfolded protein response enhanced human PH-20 secretion in Pichia pastoris.

Hyaluronidases catalyze the degradation of hyaluronan (HA), which is finding rising applications in medicine, cosmetic, and food industries. Recombinant expression of hyaluronidases in microbial hosts has been given special attention as a sustainable way to substitute animal tissue-derived hyaluronidases. In this study, we focused on optimizing the secretion of hyaluronidase from Homo sapiens in Pichia pastoris by secretion pathway engineering. The recombinant hyaluronidase was first expressed under the control of a constitutive promoter PGCW14. Then, two endoplasmic reticulum-related secretory pathways were engineered to improve the secretion capability of the recombinant strain. Signal peptide optimization suggested redirecting the protein into co-translational translocation using the ost1-proα signal sequence improved the secretion level by 20%. Enhancing the co-translational translocation by overexpressing signal recognition particle components further enhanced the secretory capability by 48%. Then, activating the unfolded protein response by overexpressing a transcriptional factor ScHac1p led to a secreted hyaluronidase activity of 4.06 U/mL, which was 2.1-fold higher than the original strain. Finally, fed-batch fermentation elevated the production to 19.82 U/mL. The combined engineering strategy described here could be applied to enhance the secretion capability of other proteins in yeast hosts. KEY POINTS: • Improving protein secretion by enhancing co-translational translocation in P. pastoris was reported for the first time. • Overexpressing Hac1p homologous from different origins improved the rhPH-20 secretion. • A 4.9-fold increase in rhPH-20 secretion was achieved after fermentation optimization and fed-batch fermentation.

Characterization of carbonaceous particles by single particle aerosol mass spectrometer in the urban area of Chengdu, China.

Carbonaceous particles are an important chemical component of atmospheric fine particles. In this study, a single particle aerosol mass spectrometer was used to continuously measure the carbonaceous particles in Chengdu, one of the megacities most affected by haze in China, from January 22 to March 3, 2021. During the observation period, the average mass concentration of PM2.5 was 62.3 ± 37.2 μg m-3, and the emissions from mobile sources were more prominent. Carbonaceous particles accounted for 68.6% of the total particles and could be classified into 10 categories, with elemental carbon (EC) mixed with sulfate (EC-S) particles making the highest contribution (33.1%). EC particles rich in secondary components and organic carbon (OC) particles rich in secondary component exhibited different diurnal variations, suggesting different sources and mixing mechanisms. From "excellent" to "polluted" days, the contributions of EC-S, EC mixed with sulfate and nitrate (EC-SN) and OC mixed with EC (OC-EC) particles increased by 9.8%, 4.5% and 6.6%, respectively, and thus these particles are key targets for future pollution control. The potential source contribution of the southwest area was stronger than that of other areas, and the potential contribution of regional transport to EC-related particles was stronger than to OC-related particles. Most particles were highly mixed with sulfate or nitrate, and the level of secondary mixing further enhanced as pollution worsened.