Surface Acoustic Wave Immunosensor for Detection of Botulinum Neurotoxin.

A Love-type acoustic wave sensor (AT-cut quartz substrate, SiO2 guiding layer) with a center frequency of approximately 120 MHz was used to detect a simulant of pathogenic botulinum neurotoxin type A-recombinant of BoNT-A light chain-in liquid samples. The sensor was prepared by immobilizing monoclonal antibodies specific for botulinum neurotoxin via a thiol monolayer deposited on a gold substrate. Studies have shown that the sensor enables selective analyte detection within a few minutes. In addition, the sensor can be used several times (regeneration of the sensor is possible using a low pH buffer). Nevertheless, the detectability of the analyte is relatively low compared to other analytical techniques that can be used for rapid detection of botulinum neurotoxin. The obtained results confirm the operation of the proposed sensor and give hope for further development of this label-free technique for detecting botulinum neurotoxin.

Changing particle content of the modern desert dust storm: a climate × health problem.

Climate and land use changes together are altering the particle content of desert dust storms on regional and local scales. These storms now carry a wide variety of pollutants and pathogens arising from urbanization, industrialization, mass transportation, warfare, or aerosolized waste in locations worldwide where deserts are intertwined with built infrastructure, transportation centers, and high-density human habitation. Accordingly, the modern desert dust storm has an anthropogenic particle load which presumably sets it apart from pre-industrial dust storms. Evidence for how particle content for modern dust storms is changing over the Arabian Peninsula holds relevance because dust storms are now more frequent and more severe. Furthermore, the Arabian Peninsula has asthma rates which are the highest worldwide. How the modern desert dust storm contributes to asthma and human health is a nascent issue. Meanwhile, public health decisions can benefit from a climate × health framework for dust storms, as proposed here. An imperative is testing each dust storm's particle content type, and for this, we propose the A-B-C-X model. Sampling a dust storm for its particle content data and then archiving samples for future analyses is advised. A storm's particle content data, once combined with its atmospheric data, allows a particle's source, transport, and deposition to be determined. In closing, the modern desert dust storm's changing particle content has far-reaching consequences for public health, transboundary issues, and international climate dialog. SIGNIFICANCE : Locally and regionally sourced particle pollution is a growing problem in deserts worldwide. Proposed here is a climate × health framework for studying how dust storm particles, entrained from both natural and engineered systems, may be contributing to declining human respiratory health.

Organic aerosols in the inland Tibetan Plateau: New insights from molecular tracers.

Aerosols affect the radiative forcing of the global climate and cloud properties. Organic aerosols are among the most important, yet least understood, components of the sensitive Tibetan Plateau atmosphere. Here, the concentration of and the seasonal and diurnal variations in biomass burning and biogenic aerosols, and their contribution to organic aerosols in the inland Tibetan Plateau were investigated using molecular tracers. Biomass burning tracers including levoglucosan and its isomers, and aromatic acids showed higher concentrations during winter than in summer. Molecular tracers of primary and secondary biogenic organic aerosols were more abundant during summer than those in winter. Meteorological conditions were the main factors influencing diurnal variations in most organic molecular tracers during both seasons. According to the tracer-based method, we found that biogenic secondary organic aerosols (38.5 %) and fungal spores (14.4 %) were the two dominant contributors to organic aerosols during summer, whereas biomass burning (15.4 %) was an important aerosol source during winter at remote continental background site. Results from the positive matrix factor source apportionment also demonstrate the importance of biomass burning and biogenic aerosols in the inland Tibetan Plateau. During winter, the long-range transport of biomass burning from South Asia contributes to organic aerosols. In contrast, the precursors, biogenic secondary organic aerosols, and fungal spores from local emissions/long-range transport are the major sources of organic aerosols during summer. Further investigation is required to distinguish between local emissions and the long-range transport of organic aerosols. In-depth insights into the organic aerosols in the Tibetan Plateau are expected to reduce the uncertainties when evaluating aerosol effects on the climate system in the Tibetan Plateau.

Characterization of sub-pollen particles in size-resolved atmospheric aerosol using chemical tracers.

Pollen grains may contain allergens that exacerbate allergic respiratory diseases like asthma and rhinitis. In the presence of water, pollen grains (10-100 µm) can rupture to produce sub-pollen particles (SPP) with diameters <2.5 µm, which in comparison to intact pollen grains, have longer atmospheric lifetimes and greater penetration to the lower lung. The current study examines SPP, fungal spores, and bacteria in size-resolved atmospheric particulate matter (PM) using chemical and biological tracers. During springtime tree pollen season in Iowa City, Iowa, fine particle (PM2.5) concentrations of fructose (a pollen chemical tracer) increased on rainy sampling periods, especially during severe thunderstorms, and peaked when a tornado struck nearby. Submicron fluorescent particles, measured by single-particle fluorescence spectroscopy, were also enhanced during rain events, particularly thunderstorms in agreement with the chemical tracer measurements. PM2.5 sucrose (a pollen chemical tracer) concentrations were higher in early spring when nighttime temperatures were closer to freezing, while fructose concentrations were higher in late spring with warmer temperatures, consistent with chemical tracers being sensitive to seasonal temperature influences. The first co-located measurements of fructose and Bet v 1 (birch pollen allergen), indicated that SPP ranged in diameter from <0.25 to 2.5 µm during rainy sampling periods and that allergens and carbohydrates exhibited distinct size distributions. Meanwhile, mannitol (a fungal spore tracer) peaked on warm, dry days following rain and was primarily in supermicron particles (>1.0 µm), which is consistent with intact fungal spore diameters (1-30 µm). Bacterial endotoxins in PM also increased during extreme weather events, primarily in supermicron particles. While the concentrations of fructose, mannitol, and endotoxin all increased in PM2.5 µm during thunderstorms, the greatest relative increase in concentration was observed for fructose. Together, these observations suggest that SPP containing starch granules and allergens (Bet v 1) were released during rainy sampling periods. This study advances the use of chemical tracers to track SPP and other bioaerosols in the atmosphere, by providing new insight to their size distribution and response to extreme weather conditions.

[Characteristics and Impact Factors of Number Concentration of Primary Biological Aerosol Particles in Beijing].

Primary biological aerosol particles (PBAP) are an important part of ambient aerosols. Both living and dead organisms not only influence human health and air quality but also play important roles in regulating certain atmospheric processes and affect the hydrological cycle and climate change. In this study, flow cytometry (FCM) was utilized in combination with the simultaneous use of permeant (SYBR Green I) and impermeant (propidium iodide, PI) nucleic acid fluorescent staining to detect and quantify the viable and dead airborne biological particles. At the same time, based on this method, the dead/viable PBAP in a Beijing urban area was detected and quantified. Moreover, the influence of environmental factors on the concentrations of primary biological aerosol particles was illuminated. The results showed that the media number concentration of dead and alive PBAP in the Beijing urban area during summer (1.03×106 m-3 and 7.43×105 m-3, respectively) were higher than those during winter (7.34×105 m-3and 6.18×105 m-3, respectively). Statistical analysis showed that there was no significant correlation between PBAP number concentration and environmental factors, i.e., meteorological conditions and air quality, showing a weak positive correlation with temperature and humidity and weak negative correlations with O3, maximum wind speed, and sunshine duration. The number concentration of PBAP was weakly correlated with the mass concentration of PM2.5 but positively correlated with that of coarse particulate matter (PM2.5-10). Both stable weather and dust transport could increase the number concentration of PBAP in Beijing.

Optimizing the Sensitivity of Biological Particle Detectors through Atmospheric Particle Analysis According to Climatic Characteristics in South Korea.

Biological agents used in biological warfare or bioterrorism are also present in bioaerosols. Prompt identification of a biological weapon and its characteristics is necessary. Herein, we optimized an environmentally adaptive detection algorithm that can better reflect changes in the complex South Korean environment than the current models. The algorithm distinguished between normal and biological particles using a laser-induced fluorescence-based biological particle detector capable of real-time measurements and size classification. We ensured that the algorithm operated with minimal false alarms in any environment by training based on experimental data acquired from an area where rainfall, snow, fog and mist, Asian dust, and water waves on the beach occur. To prevent time and money wastage due to false alarms, the detection performance for each level of sensitivity was examined to enable the selection of multiple sensitivities according to the background, and the appropriate level of sensitivity for the climate was determined. The basic sensitivity was set more conservatively than before, with a 3% alarm rate at 20 agent-containing particles per liter of air (ACPLA) and a 100% alarm rate at 63 ACPLA. The reliability was increased by optimizing five variables. False alarms did not occur in situations where no alarm was unnecessary.

Retrospective analysis of laboratory-acquired infection in China / 中国热带医学

@#Abstract: Objective To collect the cases of laboratory-acquired infections (LAI) reported in literatures in China, summarize the infection routes and causes of LAI in China, in order to improve laboratory staff's understanding of its occupational health and safety risks. Methods　The cases of laboratory-acquired infection reported in domestic literatures were collected from PubMed, CNKI, Wanfang Database, CBM China Biomedical Literature Database up to April 11, 2022, retrospectively analyze the number and causes of LAI reports, the main risk factors of LAI and its harm to society, the consequences of LAI or the leakage of pathogenic microorganisms, and put forward the relevant countermeasures of biological safety. Results　A total of 22 LAI reports were collected, reviewed and integrated into 21 reports. There were 7 kinds of pathogenic microorganisms. The main pathogenic microorganisms were hantavirus (42.86%, n=9) and Brucella (33.33%, n=7). There were 122 cases and 3 deaths in the laboratory. Most of the reports came from research laboratories (66.67%, n=14). The main route of infection was inhalation of aerosol (42.86%, n=9), followed by transdermal route (38.09%, n=8). Conclusions Failure to report LAI events will increase the risk of pathogenic microorganisms spreading to people outside the laboratory and the environment through infected laboratory staff. Local health institutions and laboratories should be encouraged to report LAI cases as a powerful tool for monitoring accidental leakage of pathogenic microorganisms and further improving laboratory biosafety. The laboratory needs strong biosafety measures to protect staff's health and prevent environmental pollution caused by accidental leakage of pathogenic microorganisms.

Unifying atmospheric biology research for the U.S. scientific community.

A global COVID-19 pandemic, rising asthma and allergies, along with climate change impacting storm intensity and frequency, point to an urgent need to unify U.S. atmospheric biology research. To this end, we briefly define atmospheric biology, summarize its fragmented history, and then outline how to unify the field to provide benefits for the U.S. science community and its citizens. Atmospheric biology refers to the study of concentrations, sources, sinks, transformation, and impacts of airborne microorganisms inclusive of pollen, fungal spores, algae, lichens, bacteria, viruses, cellulose fibers, and other biomolecules or fragments of cells. Here our focus is biological particles, both respirable (PM10 ) and systemic (PM2.5 ). Due to its interdisciplinary dependencies and broadness of scales from nanometers to kilometers, atmospheric biology research is highly fragmented in the U.S. science community. It lacks shared paradigms and common vocabulary. This deficit calls for recognizing atmospheric biology as a research community in its own right, thereby linking human health to climate change. We need to recognize atmospheric biology's importance to national security and science diplomacy. Advanced atmospheric biology research is being conducted in Europe, Russia, and China, not in the United States.

Summertime fluorescent bioaerosol particles in the coastal megacity Tianjin, North China.

Primary biological particles are an important subset of atmospheric aerosols. They have significant impacts on climate change and public health. Tianjin is a coastal megacity in the North China Plain, which is affected by both anthropogenic activities and marine air masses. To study the abundance and dynamic change of bioaerosols in Tianjin, fluorescent biological aerosol particles (FBAPs) in Tianjin were investigated by a wideband integrated bioaerosol sensor (WIBS-4A) in terms of number concentrations and size distributions in summer (11th -25th August 2018). Meanwhile, total suspended particles were collected and analyzed for chemical compounds to identify potential sources of bioaerosols. WIBS data showed that fluorescent biological particles exhibited two peaks at sunrise (~7:00) and in the evening (~20:00), which were probably caused by the enhancement of fungal spores and bacteria. Three rain events occurred during the observation period. Precipitation enhanced the abundance of biological particles, which were likely released from vegetation leaves, resuspended from soil surfaces, and/or carried by raindrops from high altitudes. The abundance of biological particles showed no significant correlation with Na+ (r = -0.17), indicating the air masses from marine areas carried limited biological particles compared to those from continental areas.

Overview of primary biological aerosol particles from a Chinese boreal forest: Insight into morphology, size, and mixing state at microscopic scale.

Biological aerosols play an important role in atmospheric chemistry, clouds, climate, and public health. Here, we studied the morphology and composition of primary biological aerosol particles (PBAPs) collected in the Lesser Khingan Mountain boreal forest of China in summertime using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). C, N, O, P, K, and Si were detected in most of the PBAPs, and P represented a major marker to discriminate the PBAPs. Of all detected particles >100 nm in diameter, 13% by number were identified as PBAPs. We found that one type of PBAPs mostly appeared as similar rod-like shapes with an aspect ratio > 1.5. Size distribution of the rod-like PBAPs displays two typical peaks at 1.4 µm and 3.5 µm, which likely are bacteria and fungal particles. The second most PBAPs were identified as fungal spores with ovoid, sub-globular or elongated shapes with a smooth surface and small protuberances with their dominant size range of 2-5 µm. Moreover, we found some large brochosomal clusters containing hundreds of brochosomes with a size range of 200-700 nm and a shape like a truncated icosahedron. We estimated that mass concentration of PBAPs approximately 1.9 µg m-3 and contributed 47% of the in situ PM2.5-10 mass. The detection frequency and concentration of PBAPs were higher at night than in the daytime, suggesting that the relative humidity dramatically enhanced the PBAPs emissions in the boreal forest. Our study also showed that the fresh PBAPs displayed weak hygroscopicity with a growth factor of ~1.09 at RH = 94%. TEM analysis revealed that about 20% of the rod-like PBAPs were internally mixed with metal, mineral dust, and inorganic salts in the boreal forest air. This work for the first time provides the overview of individual PBAPs from nanoscale to microscale in Chinese boreal forest air.

On-line measurement of fluorescent aerosols near an industrial zone in the Yangtze River Delta region using a wideband integrated bioaerosol spectrometer.

In this work, we present on-line fluorescent aerosol measurements by the wideband integrated bioaerosol spectrometer (WIBS-4A) near an industrial zone in Nanjing, a megacity in the Yangtze-River-Delta (YRD) region. The fieldwork was conducted from April 1 to May 8, 2014. A TSI. 3321 aerosol-particle-sizer (APS) was simultaneously deployed to measure the total number size distribution of aerosol with diameter from 0.8-20 µm. Both WIBS-4A and APS reported similar number concentration and temporal profiles (R2 = 0.72). However, the daily average number of potential bioaerosols was only 0.5 ±â€¯0.2% of the total particles detected by the WIBS-4A and displayed a completely different diurnal profile from that of APS. In addition, WIBS-4A can only provide integrated fluorescent signals, which strongly limited the potential to specifically identify the bioaerosols. Accordingly, hierarchical-agglomerative-cluster-analysis (HACA) was utilized to identify and speciate the potential bioaerosols from the WIBS-4A dataset. By maximizing the total distances among all potential cluster centers, a 12-cluster solution was accepted as the optimum result. These clusters were further identified according to their fluorescent signatures, size, and morphology, i.e., non-bioaerosols, bacteria, and fungal spores and/or pollen fragments. Bacteria were the dominant bioaerosol species detected in this work. The diurnal profiles of bioaerosols correlated very well with relatively humidity (RH), reaching daily maxima around 3 AM~6 AM, indicating the presence of humidity controlled bioaerosol emission mechanism, i.e., bacteria may flourish under moderate ambient temperature, RH, and the absence of UV radiation. The size- and AF-distributions of bioaerosols indicated that bioaerosols normally varied substantially in size and assumed a rather irregular shape. Although the number concentration of bioaerosols was relatively small, most bioaerosols can efficiently serve as ice nuclei by providing rough and irregular surfaces, verified by the observation results. Therefore, WIBS-4A measurements can still be informative for investigations of bioaerosols in the atmosphere, especially when HACA method was incorporated into the data processing.

Fluorescent biological aerosol particles: Concentrations, emissions, and exposures in a northern California residence.

Residences represent an important site for bioaerosol exposure. We studied bioaerosol concentrations, emissions, and exposures in a single-family residence in northern California with 2 occupants using real-time instrumentation during 2 monitoring campaigns (8 weeks during August-October 2016 and 5 weeks during January-March 2017). Time- and size-resolved fluorescent biological aerosol particles (FBAP) and total airborne particles were measured in real time in the kitchen using an ultraviolet aerodynamic particle sizer (UVAPS). Time-resolved occupancy status, household activity data, air-change rates, and spatial distribution of size-resolved particles were also determined throughout the house. Occupant activities strongly influenced indoor FBAP levels. Indoor FBAP concentrations were an order of magnitude higher when the house was occupied than when the house was vacant. Applying an integral material-balance approach, geometric mean of total FBAP emissions from human activities observed to perturb indoor levels were in the range of 10-50 million particles per event. During the summer and winter campaigns, occupants spent an average of 10 and 8.5 hours per day, respectively, awake and at home. During these hours, the geometric mean daily-averaged FBAP exposure concentration (1-10 µm diameter) was similar for each subject at 40 particles/L for summer and 29 particles/L for winter.

[Impact of Gusty Northwesterly Winds on Biological Particles in Winter in Beijing].

Biological aerosol particles play a crucial role in cloud formation and succession of ecosystems and have a large impact on human health. However, the variations in the concentration, composition, and viability of biological particles remain unclear. This study, conducted in January 2013 and January 2015 in Beijing, explores the influence of meteorological conditions on the variations in the concentration and composition of biological particles. Concentrations of biological particles were measured by an online optical detector, waveband integrated bioaerosol sensor (WIBS-4A). The composition of bacterial communities within biological particles was measured by 16S rDNA sequencing. The results showed that the number concentration of biological particles ranged from 2 L-1 to 150 L-1 during winter. The wind could largely influence the concentration and composition of biological particles. During gusty northwesterly winds, when wind speed was above 4 m·s-1 and wind direction was from the northwest (~30°), the concentration increased by one order of magnitude, and the composition of bacterial communities sharply changed. After the passage of gusty winds, the composition gradually changed back to its prior state.

Source Identification of Coarse Particles in the Desert Southwest, USA using Positive Matrix Factorization.

The Desert Southwest Coarse Particulate Matter Study was undertaken to further our understanding of the spatial and temporal variability and sources of fine and coarse particulate matter (PM) in rural, arid, desert environments. Sampling was conducted between February 2009 and February 2010 in Pinal County, AZ near the town of Casa Grande where PM concentrations routinely exceed the U.S. National Ambient Air Quality Standards (NAAQS) for both PM10 and PM2.5. In this desert region, exceedances of the PM10 NAAQS are dominated by high coarse particle concentrations, a common occurrence in this region of the United States. This work expands on previously published measurements of PM mass and chemistry by examining the sources of fine and coarse particles and the relative contribution of each to ambient PM mass concentrations using the positive matrix factorization receptor model (Clements et al., 2014). Coarse particles within the region were apportioned to nine sources including primary biological aerosol particles (PBAPs - 25%), crustal material (20%), re-entrained road dust (11%), feedlot (11% at the site closest to a cattle feedlot), secondary particles (10%), boron-rich crustal material (9%), and transported soil (6%), with minor contributions from ammonium nitrate, and salt (considered to be NaCl). Fine particles within the region were apportioned to six sources including motor vehicles (37%), road dust (29%), lead-rich (10%), with minor contributions from brake wear, crustal material, and salt. These results can help guide local air pollution improvement strategies designed to reduce levels of PM to below the NAAQS.