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1.
J Aerosol Med Pulm Drug Deliv ; 37(2): 90-99, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38640447

ABSTRACT

This section aims to provide a concise and contemporary technical perspective and reference resource covering dry powder inhaler (DPI) formulations. While DPI products are currently the leading inhaled products in terms of sales value, a number of confounding perspectives are presented to illustrate why they are considered surprisingly, and often frustratingly, poorly understood on a fundamental scientific level, and most challenging to design from first principles. At the core of this issue is the immense complexity of fine cohesive powder systems. This review emphasizes that the difficulty of successful DPI product development should not be underestimated and is best achieved with a well-coordinated team who respect the challenges and who work in parallel on device and formulation and with an appreciation of the handling environment faced by the patient. The general different DPI formulation types, which have evolved to address the challenges of aerosolizing fine cohesive drug-containing particles to create consistent and effective DPI products, are described. This section reviews the range of particle engineering processes that may produce micron-sized drug-containing particles and their subsequent assembly as either carrier-based or carrier-free compositions. The creation of such formulations is then discussed in the context of the material, bulk, interfacial and ultimately drug-delivery properties that are considered to affect formulation performance. A brief conclusion then considers the future DPI product choices, notably the issue of technology versus affordability in the evolving inhaler market.


Subject(s)
Drug Delivery Systems , Dry Powder Inhalers , Humans , Administration, Inhalation , Pharmaceutical Preparations , Particle Size , Powders , Aerosols
2.
Anal Chem ; 96(15): 5860-5868, 2024 Apr 16.
Article in English | MEDLINE | ID: mdl-38567987

ABSTRACT

Supramolecular hydrogels formed through polymer-nanoparticle interactions are promising biocompatible materials for translational medicines. This class of hydrogels exhibits shear-thinning behavior and rapid recovery of mechanical properties, providing desirable attributes for formulating sprayable and injectable therapeutics. Characterization of hydrogel composition and loading of encapsulated drugs is critical to achieving the desired rheological behavior as well as tunable in vitro and in vivo payload release kinetics. However, quantitation of hydrogel composition is challenging due to material complexity, heterogeneity, high molecular weight, and the lack of chromophores. Here, we present a label-free approach to simultaneously determine hydrogel polymeric components and encapsulated payloads by coupling a reversed phase liquid chromatographic method with a charged aerosol detector (RPLC-CAD). The hydrogel studied consists of modified hydroxypropylmethylcellulose, self-assembled PEG-b-PLA nanoparticles, and a therapeutic compound, bimatoprost. The three components were resolved and quantitated using the RPLC-CAD method with a C4 stationary phase. The method demonstrated robust performance, applicability to alternative cargos (i.e., proteins) and was suitable for composition analysis as well as for evaluating in vitro release of cargos from the hydrogel. Moreover, this method can be used to monitor polymer degradation and material stability, which can be further elucidated by coupling the RPLC method with (1) a multi-angle light scattering detector (RPLC-MALS) or (2) high resolution mass spectrometry (RPLC-MS) and a Fourier-transform based deconvolution algorithm. We envision that this analytical strategy could be generalized to characterize critical quality attributes of other classes of supramolecular hydrogels, establish structure-property relationships, and provide rational design guidance in hydrogel drug product development.


Subject(s)
Hydrogels , Nanoparticles , Hydrogels/chemistry , Chromatography, Reverse-Phase/methods , Polyethylene Glycols/chemistry , Aerosols
3.
Environ Sci Technol ; 58(15): 6564-6574, 2024 Apr 16.
Article in English | MEDLINE | ID: mdl-38578220

ABSTRACT

Formation of highly oxygenated molecules (HOMs) such as organic peroxides (ROOR, ROOH, and H2O2) is known to degrade food and organic matter. Gas-phase unimolecular autoxidation and bimolecular RO2 + HO2/RO2 reactions are prominently renowned mechanisms associated with the formation of peroxides. However, the reaction pathways and conditions favoring the generation of peroxides in the aqueous phase need to be evaluated. Here, we identified bulk aqueous-phase ROOHs in varying organic precursors, including a laboratory model compound and monoterpene oxidation products. Our results show that formation of ROOHs is suppressed at enhanced oxidant concentrations but exhibits complex trends at elevated precursor concentrations. Furthermore, we observed an exponential increase in the yield of ROOHs when UV light with longer wavelengths was used in the experiment, comparing UVA, UVB, and UVC. Water-soluble organic compounds represent a significant fraction of ambient cloud-water components (up to 500 µM). Thus, the reaction pathways facilitating the formation of HOMs (i.e., ROOHs) during the aqueous-phase oxidation of water-soluble species add to the climate and health burden of atmospheric particulate matter.


Subject(s)
Hydrogen Peroxide , Peroxides , Particulate Matter/analysis , Oxidants , Water , Aerosols
4.
BMC Oral Health ; 24(1): 417, 2024 Apr 05.
Article in English | MEDLINE | ID: mdl-38580933

ABSTRACT

BACKGROUND: Many instruments used in dentistry are rotary, such as handpieces, water syringes, and ultrasonic scalers that produce aerosols. The spray created by these instruments can carry, in addition to water, droplets of saliva, blood, and microorganisms, which can pose a risk of infections for healthcare professionals and patients. Due to the COVID-19 pandemic, this gained attention. OBJECTIVE: The aim was to carry out a systematic review of the evidence of the scope of the aerosol produced by ultrasonic scaler in environmental contamination and the influence of the use of intraoral suction reduction devices. DESIGN: Scientific literature was searched until June 19, 2021 in 6 databases: Pubmed, EMBASE, Web of science, Scopus, Virtual Health Library and Cochrane Library, without restrictions on language or publication date. Studies that evaluated the range of the aerosol produced by ultrasonic scaler during scaling/prophylaxis and the control of environmental contamination generated by it with the use of low (LVE) and high (HVE) volume evacuation systems were included. RESULTS: Of the 1893 potentially relevant articles, 5 of which were randomized controlled trials (RCTs). The meta-analysis of 3 RCTs showed that, even at different distances from the patient's oral cavity, there was a significant increase in airborne bacteria in the dental environment with the use of ultrasonic scaler. In contrast, when meta-analysis compared the use of HVE with LVE, there was no significant difference (P = 0.40/CI -0.71[-2.37, 0.95]) for aerosol produced in the environment. CONCLUSIONS: There is an increase in the concentration of bioaerosol in the dental environment during the use of ultrasonic scaler in scaling/prophylaxis, reaching up to 2 m away from the patient's mouth and the use of LVE, HVE or a combination of different devices, can be effective in reducing air contamination in the dental environment, with no important difference between different types of suction devices.


Subject(s)
Ultrasonic Therapy , Humans , Ultrasonics , Respiratory Aerosols and Droplets , Aerosols/adverse effects , Water , Dental Scaling
5.
Front Immunol ; 15: 1277526, 2024.
Article in English | MEDLINE | ID: mdl-38605961

ABSTRACT

This study evaluated a depot-formulated cytokine-based adjuvant to improve the efficacy of the recombinant F1V (rF1V) plague vaccine and examined the protective response following aerosol challenge in a murine model. The results of this study showed that co-formulation of the Alhydrogel-adsorbed rF1V plague fusion vaccine with the depot-formulated cytokines recombinant human interleukin 2 (rhuIL-2) and/or recombinant murine granulocyte macrophage colony-stimulating factor (rmGM-CSF) significantly enhances immunogenicity and significant protection at lower antigen doses against a lethal aerosol challenge. These results provide additional support for the co-application of the depot-formulated IL-2 and/or GM-CSF cytokines to enhance vaccine efficacy.


Subject(s)
Plague Vaccine , Yersinia pestis , Humans , Animals , Mice , Cytokines , Antigens, Bacterial , Vaccines, Synthetic , Aerosols
6.
Environ Int ; 186: 108610, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38626495

ABSTRACT

Greater Cairo, the largest megacity of the Middle East North Africa (MENA) region, is currently suffering from major aerosol pollution, posing a significant threat to public health. However, the main sources of pollution remain insufficiently characterized due to limited atmospheric observations. To bridge this knowledge gap, we conducted a continuous 2-month field study during the winter of 2019-2020 at an urban background site, documenting for the first time the chemical and physical properties of submicron (PM1) aerosols. Crustal material from both desert dust and road traffic dust resuspension contributed as much as 24 % of the total PM1 mass (rising to 66 % during desert dust events), a figure not commonly observed in urban environments. Our observations showed significant decreases in black carbon concentrations and ammonium sulfate compared to data from 15 years ago, indicating an important reduction in both local and regional emissions as a result of effective mitigation measures. The diurnal variability of carbonaceous aerosols was attributed to emissions emanating from local traffic at rush hours and nighttime open biomass burning. Surprisingly, semi-volatile ammonium chloride (NH4Cl) originating from local open biomass and waste burning was found to be the main chemical species in PM1 over Cairo. Its nighttime formation contributed to aerosol water uptake during morning hours, thereby playing a major role in the build-up of urban haze. While our results confirm the persistence of a significant dust reservoir over Cairo, they also unveil an additional source of highly hygroscopic (semi-volatile) inorganic salts, leading to a unique type of urban haze. This haze, with dominant contributors present in both submicron (primarily as NH4Cl) and supermicron (largely as dust) modes, underscores the potential implications of heterogeneous chemical transformation of air pollutants in urban environments.


Subject(s)
Aerosols , Air Pollutants , Air Pollution , Environmental Monitoring , Particulate Matter , Aerosols/analysis , Air Pollutants/analysis , Egypt , Air Pollution/statistics & numerical data , Particulate Matter/analysis , Cities , Dust/analysis , Particle Size
7.
Environ Int ; 186: 108629, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38582060

ABSTRACT

Recently, extreme wildfires occur frequently around the world and emit substantial brown carbon (BrC) into the atmosphere, whereas the molecular compositions and photochemical evolution of BrC remain poorly understood. In this work, primary smoke aerosols were generated from wood smoldering, and secondary smoke aerosols were formed by the OH radical photooxidation in an oxidation flow reactor, where both primary and secondary smoke samples were collected on filters. After solvent extraction of filter samples, the molecular composition of dissolved organic carbon (DOC) was determined by Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). The molecular composition of dissolved BrC was obtained based on the constraints of DOC formulae. The proportion of dissolved BrC fractions accounted for approximately 1/3-1/2 molecular formulae of DOC. The molecular characteristics of dissolved BrC showed higher levels of carbon oxidation state, double bond equivalents, and modified aromaticity index than those of DOC, indicating that dissolved BrC fractions were a class of organic structures with relatively higher oxidation state, unsaturated and aromatic degree in DOC fractions. The comparative analysis suggested that aliphatic and olefinic structures dominated DOC fractions (contributing to 70.1%-76.9%), while olefinic, aromatic, and condensed aromatic structures dominated dissolved BrC fractions (contributing to 97.5%-99.9%). It is worth noting that dissolved BrC fractions only contained carboxylic-rich alicyclic molecules (CRAMs)-like structures, unsaturated hydrocarbons, aromatic structures, and highly oxygenated compounds. CRAMs-like structures were the most abundant species in both DOC and dissolved BrC fractions. Nevertheless, the specific molecular characteristics for DOC and dissolved BrC fractions varied with subgroups after aging. The results highlight the similarities and differences in the molecular compositions and characteristics of DOC and dissolved BrC fractions with aging. This work will provide insights into understanding the molecular composition of DOC and dissolved BrC in smoke.


Subject(s)
Aerosols , Carbon , Smoke , Wood , Carbon/analysis , Carbon/chemistry , Smoke/analysis , Wood/chemistry , Aerosols/analysis , Aerosols/chemistry , Oxidation-Reduction , Wildfires , Air Pollutants/analysis , Air Pollutants/chemistry , Photochemical Processes
8.
Sci Total Environ ; 927: 172278, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38583631

ABSTRACT

The Wells-Riley model is extensively used for retrospective and prospective modelling of the risk of airborne transmission of infection in indoor spaces. It is also used when examining the efficacy of various removal and deactivation methods for airborne infectious aerosols in the indoor environment, which is crucial when selecting the most effective infection control technologies. The problem is that the large variation in viral load between individuals makes the Wells-Riley model output very sensitive to the input parameters and may yield a flawed prediction of risk. The absolute infection risk estimated with this model can range from nearly 0 % to 100 % depending on the viral load, even when all other factors, such as removal mechanisms and room geometry, remain unchanged. We therefore propose a novel method that removes this sensitivity to viral load. We define a quanta-independent maximum absolute before-after difference in infection risk that is independent of quanta factors like viral load, physical activity, or the dose-response relationships. The input data needed for a non-steady-state calculation are just the removal rates, room volume, and occupancy duration. Under steady-state conditions the approach provides an elegant solution that is only dependent on removal mechanisms before and after applying infection control measures. We applied this method to compare the impact of relative humidity, ventilation rate and its effectiveness, filtering efficiency, and the use of ultraviolet germicidal irradiation on the infection risk. The results demonstrate that the method provides a comprehensive understanding of the impact of infection control strategies on the risk of airborne infection, enabling rational decisions to be made regarding the most effective strategies in a specific context. The proposed method thus provides a practical tool for mitigation of airborne infection risk.


Subject(s)
Air Microbiology , Air Pollution, Indoor , Humans , Air Pollution, Indoor/prevention & control , Aerosols/analysis , COVID-19/prevention & control , COVID-19/transmission , Ventilation , Viral Load , Models, Theoretical , Infection Control/methods , Risk Assessment
9.
J Phys Chem A ; 128(15): 3015-3023, 2024 Apr 18.
Article in English | MEDLINE | ID: mdl-38593044

ABSTRACT

Respiratory viruses, such as influenza and severe acute respiratory syndrome coronavirus 2, represent a substantial public health burden and are largely transmitted through respiratory droplets and aerosols. Environmental factors such as relative humidity (RH) and temperature impact virus transmission rates, and a precise mechanistic understanding of the connection between these environmental factors and virus transmission would improve efforts to mitigate respiratory disease transmission. Previous studies on supermicrometer particles observed RH-dependent phase transitions and linked particle phase state to virus viability. Phase transitions in atmospheric aerosols are dependent on size in the submicrometer range, and actual respiratory particles are expelled over a large size range, including submicrometer aerosols that can transmit diseases over long distances. Here, we directly investigated the phase transitions of submicrometer model respiratory aerosols. A probe molecule, Nile red, was added to particle systems including multiple mucin/salt mixtures, a growth medium, and simulated lung fluid. For each system, the polarity-dependent fluorescence emission was measured following RH conditioning. Notably, the fluorescence measurements of mucin/NaCl and Dulbecco's modified Eagle's medium particles indicated that liquid-liquid phase separation (LLPS) also occurs in submicron particles, suggesting that LLPS can also impact the viability of viruses in submicron particles and thus affect aerosol virus transmission. Furthermore, the utility of fluorescence-based measurements to study submicrometer respiratory particle physicochemical properties in situ is demonstrated.


Subject(s)
Mucins , Respiratory Aerosols and Droplets , Humidity , Aerosols/chemistry
10.
J Radiol Prot ; 44(2)2024 Apr 18.
Article in English | MEDLINE | ID: mdl-38632901

ABSTRACT

The high radon concentrations measured in the indoor air of groundwater facilities and the prevalence of the problem have been known for several years. Unlike in other workplaces, in groundwater plants, radon is released into the air from the water treatment processes. During the measurements of this study, the average radon concentrations varied from 500 to 8800 Bq m-3. In addition, the indoor air of the treatment plants is filtered and there are no significant internal aerosol sources. However, only a few published studies on groundwater plants have investigated the properties of the radon progeny aerosol, such as the equilibrium factor (F) or the size distribution of the aerosol, which are important for assessing the dose received by workers. Moreover, the International Commission on Radiological Protection has not provided generic aerosol parameter values for dose assessment in groundwater treatment facilities. In this study, radon and radon progeny measurements were carried out at three groundwater plants. The results indicate surprisingly high unattached fractions (fp= 0.27-0.58), suggesting a low aerosol concentration in indoor air. The correspondingFvalues were 0.09-0.42, well below those measured in previous studies. Based on a comparison of the effective dose rate calculations, either the determination of thefpor, with certain limitations, the measurement of radon is recommended. Dose rate calculation based on the potential alpha energy concentration alone proved unreliable.


Subject(s)
Air Pollutants, Radioactive , Air Pollution, Indoor , Groundwater , Radiation Monitoring , Radon , Humans , Radon Daughters/analysis , Air Pollutants, Radioactive/analysis , Radon/analysis , Aerosols , Radiation Monitoring/methods , Air Pollution, Indoor/analysis
11.
J Hazard Mater ; 470: 134278, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38631247

ABSTRACT

Resuspension caused by human walking activities is an important source of indoor bioaerosols and has been associated with health effects such as allergies and asthma. However, it is unknown whether inhalation of resuspended bioaerosols is an important exposure pathway for airborne infection. Also, crucial factors influencing the resuspension of settled microbes have not been quantified. In this study, we experimentally investigated the resuspension of culturable bacteria from human-stepping on polyvinyl chloride (PVC) flooring under different conditions. We determined the bacterial resuspension emission factor (ER), a normalized resuspension parameter for the ratio of resuspended mass in the air to the mass of settled particles, for two common bacteria, Escherichia coli and Salmonella enterica. The investigation involved varying factors such as microbial surface-attached durations (0, 1, 2, and 3 days), the absence or presence of nutrients on flooring surfaces, and changes in relative humidity (RH) (35%, 65%, and 85%). The results showed that, in the absence of nutrients, the highest ER values for E. coli and S. enterica were 3.8 × 10-5 ± 5.2 × 10-6 and 5.3 × 10-5 ± 6.0 × 10-6, respectively, associated with surface-attached duration of 0 days. As the surface-attached duration increased from 0 to 3 days, ER values decreased by 92% and 84% for E. coli and S. enterica, respectively. In addition, we observed that ER values decreased with the increasing RH, which is consistent with particle adhesion theory. This research offers valuable insights into microbial resuspension during human walking activities and holds the potential for assisting in the assessment and estimation of risks related to human exposure to bioaerosols.


Subject(s)
Escherichia coli , Humidity , Walking , Humans , Floors and Floorcoverings , Salmonella enterica , Aerosols , Air Pollution, Indoor , Air Microbiology , Polyvinyl Chloride/chemistry , Nutrients
12.
Sci Rep ; 14(1): 8830, 2024 04 17.
Article in English | MEDLINE | ID: mdl-38632265

ABSTRACT

Face masks are essential in reducing the transmission of respiratory infections and bacterial filtration efficiency, a key parameter of mask performances, requires the use of Staphylococcus aureus and specialised staff. This study aims to develop a novel method for a preliminary screening of masks or materials filtration efficiency by a green, easy and rapid setup based on the use of a riboflavin solution, a safe autofluorescent biomolecule. The proposed setup is composed of a commercial aerosol generator commonly used for aerosol therapy, custom 3D printed aerosol chamber and sample holder, a filter for downstream riboflavin detection and a vacuum pump. The filtration efficiency of four different masks was assessed using the riboflavin-based setup and the bacterial filtration efficiency (BFE). The averaged filtration efficiency values, measured with both methods, were similar but were higher for the riboflavin-based setup (about 2% for all tested samples) than bacterial filtration efficiency. Considering the good correlation, the riboflavin-based setup can be considered validated as an alternative method to bacterial filtration efficiency for masks and related materials fabrics filtration efficiency screening but This study aims to develop a novel method for a preliminary screening of masks or materials filtration efficiency by a green, easy and rapid setup based on the use of a riboflavin solution, a safe autofluorescent biomolecule, but not to replace regulation approaches. The proposed setup can be easily implemented at low price, is more rapid and eco-friendly and can be performed in chemical-physical laboratories without the needing of biosafety laboratory and specialised operators.


Subject(s)
Masks , Respiratory Protective Devices , Humans , Respiratory Aerosols and Droplets , Filtration , Aerosols
13.
Environ Sci Technol ; 58(16): 6934-6944, 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38651174

ABSTRACT

Stratospheric aerosol injection (SAI) is proposed as a means of reducing global warming and climate change impacts. Similar to aerosol enhancements produced by volcanic eruptions, introducing particles into the stratosphere would reflect sunlight and reduce the level of warming. However, uncertainties remain about the roles of nucleation mechanisms, ionized molecules, impurities (unevaporated residuals of injected precursors), and ambient conditions in the generation of SAI particles optimally sized to reflect sunlight. Here, we use a kinetic ion-mediated and homogeneous nucleation model to study the formation of H2SO4 particles in aircraft exhaust plumes with direct injection of H2SO4 vapor. We find that under the conditions that produce particles of desired sizes (diameter ∼200-300 nm), nucleation occurs in the nascent (t < 0.01 s), hot (T = 360-445 K), and dry (RH = 0.01-0.1%) plume and is predominantly unary. Nucleation on chemiions occurs first, followed by neutral new particle formation, which converts most of the injected H2SO4 vapor to particles. Coagulation in the aging and diluting plumes governs the subsequent evolution to a narrow (σg = 1.3) particle size distribution. Scavenging by exhaust soot is negligible, but scavenging by acid impurities or incomplete H2SO4 evaporation in the hot exhaust plume and enhanced background aerosols can matter. This research highlights the need to obtain laboratory and/or real-world experiment data to verify the model prediction.


Subject(s)
Aerosols , Aircraft , Particle Size , Vehicle Emissions , Atmosphere/chemistry , Air Pollutants/chemistry
14.
Environ Monit Assess ; 196(5): 473, 2024 Apr 25.
Article in English | MEDLINE | ID: mdl-38662282

ABSTRACT

Aerosol optical depth (AOD) serves as a crucial indicator for assessing regional air quality. To address regional and urban pollution issues, there is a requirement for high-resolution AOD products, as the existing data is of very coarse resolution. To address this issue, we retrieved high-resolution AOD over Kanpur (26.4499°N, 80.3319°E), located in the Indo-Gangetic Plain (IGP) region using Landsat 8 imageries and implemented the algorithm SEMARA, which combines SARA (Simplified Aerosol Retrieval Algorithm) and SREM (Simplified and Robust Surface Reflectance Estimation). Our approach leveraged the green band of the Landsat 8, resulting in an impressive spatial resolution of 30 m of AOD and rigorously validated with available AERONET observations. The retrieved AOD is in good agreement with high correlation coefficients (r) of 0.997, a low root mean squared error of 0.035, and root mean bias of - 4.91%. We evaluated the retrieved AOD with downscaled MODIS (MCD19A2) AOD products across various land classes for cropped and harvested period of agriculture cycle over the study region. It is noticed that over the built-up region of Kanpur, the SEMARA algorithm exhibits a stronger correlation with the MODIS AOD product compared to vegetation, barren areas and water bodies. The SEMARA approach proved to be more effective for AOD retrieval over the barren and built-up land categories for harvested period compared with the cropping period. This study offers a first comparative examination of SEMARA-retrieved high-resolution AOD and MODIS AOD product over a station of IGP.


Subject(s)
Aerosols , Air Pollutants , Cities , Environmental Monitoring , Satellite Imagery , India , Environmental Monitoring/methods , Aerosols/analysis , Air Pollutants/analysis , Air Pollution/statistics & numerical data , Algorithms
15.
PLoS One ; 19(4): e0300050, 2024.
Article in English | MEDLINE | ID: mdl-38574045

ABSTRACT

The quantification of aerosol size distributions is crucial for understanding the climate and health impacts of aerosols, validating models, and identifying aerosol sources. This work provides one of the first continuous measurements of aerosol size distribution from 1.02 to 8671 nm near the shore of Lake Michigan. The data were collected during the Lake Michigan Ozone Study (LMOS 2017), a comprehensive air quality measurement campaign in May and June 2017. The time-resolved (2-min) size distribution are reported herein alongside meteorology, remotely sensed data, gravimetric filters, and gas-phase variables. Mean concentrations of key aerosol parameters include PM2.5 (6.4 µg m-3), number from 1 to 3 nm (1.80x104 cm-3) and number greater than 3 nm (8x103 cm-3). During the field campaign, approximately half of days showed daytime ultrafine burst events, characterized by particle growth from sub 10 nm to 25-100 nm. A specific investigation of ultrafine lake spray aerosol was conducted due to enhanced ultrafine particles in onshore flows coupled with sustained wave breaking conditions during the campaign. Upon closer examination, the relationships between the size distribution, wind direction, wind speed, and wave height did not qualitatively support ultrafine particle production from lake spray aerosol; statistical analysis of particle number and wind speed also failed to show a relationship. The alternative hypothesis of enhanced ultrafine particles in onshore flow originating mainly from new particle formation activity is supported by multiple lines of evidence.


Subject(s)
Air Pollutants , Lakes , Lakes/analysis , Particle Size , Aerosolized Particles and Droplets , Particulate Matter/analysis , Aerosols/analysis , Air Pollutants/analysis , Environmental Monitoring
16.
Environ Sci Technol ; 58(16): 7196-7207, 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38597822

ABSTRACT

Aerosols produced in the amine carbon capture process can lead to secondary environmental pollution. This study employs molecular dynamics (MD) simulations to investigate cluster formation, amine behavior, and aerosol growth of amines, essential for reducing amine aerosol emissions. Results showed that the cluster evolution process can be divided into cluster formation and growth in terms of molecular content, and the nucleation rate for the present systems was estimated in the order of 1028 cm-3 s-1. CO2 absorption was observed alongside successful nucleation, with CO2 predominantly localizing in the cluster's outer layer postabsorption. Monoethanolamine (MEA) exhibited robust electrostatic interactions with other components via hydrogen bonding, leading to its migration toward regions where CO2 and H2O coexisted within the cluster. While MEA presence markedly spurred cluster formation, its concentration had a marginal effect on the final cluster size. Elevating water content can augment the aerosol growth rate. However, altering the gas saturation is possible only within narrow confines by introducing vapor. Contrarily, gas cooling introduced dual, opposing effects on aerosol growth. These findings, including diffusion coefficients and growth rates, enhance theoretical frameworks for predicting aerosol formation in absorbers, aiding in mitigating environmental impacts of amine-based carbon capture.


Subject(s)
Aerosols , Carbon Dioxide , Carbon Dioxide/chemistry , Molecular Dynamics Simulation , Amines/chemistry
17.
Rapid Commun Mass Spectrom ; 38(10): e9737, 2024 May 30.
Article in English | MEDLINE | ID: mdl-38533583

ABSTRACT

RATIONALE: Human exhaled breath usually contains unique proteins that may provide clues to characterize individual physiological activities and many diseases. However, the concentration of exhaled proteins in exhaled breath is extremely low and usually does not reach the detection limits of all online breath mass spectrometry instruments. Therefore, developing a new breath sampler for collecting and characterizing exhaled proteins is important. METHODS: In this study, a new mask-based wearable sampler was developed by fixing metal materials into the inner surface of the KN95 mask. Human exhaled proteins could be directly adsorbed onto the metal material while wearing the mask. After sampling, the collected proteins were eluted, digested, and identified using nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS). RESULTS: The adsorption of exhaled proteins was evaluated, showing that modified gold foil is an effective material for collecting exhaled proteins. Various endogenous proteins were successfully identified from exhaled breath, many of which can be potential biomarkers for disease diagnosis. CONCLUSIONS: By coupling the newly developed mask sampler with nano-LC-MS/MS, human exhaled proteins were successfully collected and identified. Our results show that the mask sampler is wearable, simple, and convenient, and the method is noninvasive for investigating disease diagnosis and human health.


Subject(s)
Tandem Mass Spectrometry , Wearable Electronic Devices , Humans , Tandem Mass Spectrometry/methods , Pilot Projects , Breath Tests/methods , Chromatography, Liquid/methods , Aerosols
18.
J Environ Sci (China) ; 142: 248-258, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38527890

ABSTRACT

Brown carbon (BrC) is one of the important light absorption substances that have high light absorption ability under short wavelength light. However, limit studies have focused on the BrC emission from ships. In this study, size-segregated particulate matters (PM) were collected from three different types of ships, light absorption characteristics and size distribution of methanol-soluble BrC and water-soluble BrC in PM from ship exhausts were investigated. Results showed that four-stroke low-power diesel fishing boat (4-LDF) had the highest mass concentrations of methanol-soluble organic carbon (MSOC) and water-soluble organic carbon (WSOC), followed by 2-stroke high-power heavy-fuel-oil vessel (2-HHV), and four-stroke high-power marine-diesel vessel (4-HMV). While 2-HHV had obviously higher light absorption coefficients of methanol-soluble BrC (Abs365,M) and water-soluble BrC (Abs365,W) in unit weight of PM than the other two types of ships. The tested ships presented comparable or higher absorption efficiency of BrC in water extracts (MAE365,W) compared with other BrC emission sources. Majority of BrC was concentrated in fine particles, and the particle size distributions of both Abs365,M and Abs365,W showed bimodal patterns, peaking at 0.43-0.65 µm and 4.7-5.8 µm, respectively. However, different particle size distributions were found for MAE365,M between diesel and heavy fuel oil ships. Besides, different wavelength dependence in particles with different size were also detected. Ship exhaust could be confirmed as a non-ignorable BrC emission source, and complex influencing factor could affect the light absorption characteristics of ship emissions. Particle size should also be considered when light absorption ability of BrC was evaluated.


Subject(s)
Air Pollutants , Air Pollutants/analysis , Ships , Carbon/analysis , Methanol , Environmental Monitoring/methods , Aerosols/analysis , Particulate Matter/analysis , Vehicle Emissions , Water , China
19.
Gynecol Endocrinol ; 40(1): 2328619, 2024 Dec.
Article in English | MEDLINE | ID: mdl-38528806

ABSTRACT

OBJECTIVE: To synthesize the primary evidence on the efficacy and safety of visnadine on symptoms of sexual dysfunction (SD) in heterosexual women. METHODS: We conducted a systematic review of randomized clinical trials (RCTs) with a primary search without language restriction in PubMed/Medline, Scopus, Embase, Web of Science, Cochrane Library, and international clinical trial registries. Trials reporting the use of visnadine by any route in women with SD were eligible. We performed screening, data extraction, and risk of bias assessment in a double-blind approach. The primary outcomes were the Female Sexual Function Index (FSFI) and its domains. Secondary outcomes were safety, arousal, lubrication, pleasure, orgasm, negative sensations, duration, and overall satisfaction. RESULTS: Initially, 242 records were retrieved. We selected nine papers for full-text reading and finally included two RCTs: one with a parallel design and one with a crossover design with a total of 96 patients. One study compared visnadine aerosol with a placebo, while the other compared different frequencies of visnadine aerosol use. Visnadine use showed a statistically significant improvement (p < 0.05) in overall FSFI scores, regardless of the frequency of use. A meta-analysis was not possible due to the high clinical and methodological heterogeneity between available studies. CONCLUSION: RCTs regarding the use of visnadine for the Female SD are scarce and methodologically limited. This preliminary evidence shows visnadine as a potentially effective and safe option to alleviate some of the clinical symptoms of SD in heterosexual women. However, future better-designed randomized studies with larger sample numbers are required.


Subject(s)
Chromans , Heterosexuality , Sexual Dysfunction, Physiological , Female , Humans , Randomized Controlled Trials as Topic , Sexual Dysfunction, Physiological/drug therapy , Aerosols/therapeutic use
20.
Biosensors (Basel) ; 14(3)2024 Feb 24.
Article in English | MEDLINE | ID: mdl-38534229

ABSTRACT

Bioaerosols are small airborne particles composed of microbiological fragments, including bacteria, viruses, fungi, pollens, and/or by-products of cells, which may be viable or non-viable wherever applicable. Exposure to these agents can cause a variety of health issues, such as allergic and infectious diseases, neurological disorders, and cancer. Therefore, detecting and identifying bioaerosols is crucial, and bioaerosol sampling is a key step in any bioaerosol investigation. This review provides an overview of the current bioaerosol sampling methods, both passive and active, as well as their applications and limitations for rapid on-site monitoring. The challenges and trends for detecting airborne microorganisms using molecular and immunological methods are also discussed, along with a summary and outlook for the development of prompt monitoring technologies.


Subject(s)
Air Microbiology , Viruses , Aerosols/analysis , Bacteria , Fungi , Environmental Monitoring/methods
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