The mechanism for spread of SARS-CoV-2 has been attributed to large particles produced by coughing and sneezing. There is controversy whether smaller airborne particles may transport SARS-CoV-2. ...Smaller particles, particularly fine particulate matter (≤ 2.5 µm in diameter), can remain airborne for longer periods than larger particles and after inhalation will penetrate deeply into the lungs. Little is known about the size distribution and location of airborne SARS-CoV-2 RNA.
As a measure of hospital-related exposure, air samples of three particle sizes (> 10.0 µm, 10.0-2.5 µm, and ≤ 2.5 µm) were collected in a Boston, Massachusetts (USA) hospital from April to May 2020 (N = 90 size-fractionated samples). Locations included outside negative-pressure COVID-19 wards, a hospital ward not directly involved in COVID-19 patient care, and the emergency department.
SARS-CoV-2 RNA was present in 9% of samples and in all size fractions at concentrations of 5 to 51 copies m
. Locations outside COVID-19 wards had the fewest positive samples. A non-COVID-19 ward had the highest number of positive samples, likely reflecting staff congregation. The probability of a positive sample was positively associated (r = 0.95, p < 0.01) with the number of COVID-19 patients in the hospital. The number of COVID-19 patients in the hospital was positively associated (r = 0.99, p < 0.01) with the number of new daily cases in Massachusetts.
More frequent detection of positive samples in non-COVID-19 than COVID-19 hospital areas indicates effectiveness of COVID-ward hospital controls in controlling air concentrations and suggests the potential for disease spread in areas without the strictest precautions. The positive associations regarding the probability of a positive sample, COVID-19 cases in the hospital, and cases in Massachusetts suggests that hospital air sample positivity was related to community burden. SARS-CoV-2 RNA with fine particulate matter supports the possibility of airborne transmission over distances greater than six feet. The findings support guidelines that limit exposure to airborne particles including fine particles capable of longer distance transport and greater lung penetration.
Road dust particles play an important role in atmospheric pollution and are associated with adverse human health effects. Traffic emissions are a major source of particles in road dust. However, ...there has been limited information about the relationship between distance from road and traffic-related elements levels in road dust. We investigated the relationships between proximity to the nearest major roadway and trace element mass fractions in PM
10
and PM
2.5
re-suspended from the road surface, based on measurements at three different distance ranges. We found that mass fractions of Ba, Cu, Zr, Zn, Cl, Co, Cr, Ca, Ti in PM
10
road dust as well as Zr, Cu, Cl, Zn, Cr, Ti, Mn, Ca, Ni, and Fe in PM
2.5
road dust, significantly decreased with distance from major road. Most of these elements are associated with road traffic emissions, including both tailpipe and non-tailpipe emissions. The decrease rates differed among elements due to differences in local traffic contributions. The decreases for elements which are mainly associated with non-tailpipe traffic emissions (e.g., Ba, Zr) were more dramatic. Our results indicate that traffic emissions, especially non-tailpipe emissions, contribute substantially to road dust, suggesting the need for control strategies for non-tailpipe emissions.
Implications: We investigated the relationships between road proximity with trace element mass fractions in PM10 and PM2.5 re-suspended from the road surface. We observed significant decrease of traffic-related elements in PM10 and PM2.5 road dust with log distance from major road. We also found that the mass fractions for elements, which mainly come from traffic decrease more sharply compared to elements which come from both traffic and other sources. Our results indicate that traffic emissions contribute substantially to road dust, and imply that the distance to major road can be used as a proxy for ambient exposure.
Traffic-related particulate matter (PM) plays an important role in urban air pollution. However, sources of urban pollution are difficult to distinguish. This study utilises a mobile particle ...concentrator platform and statistical tools to investigate factors affecting roadway ambient coarse particle (PM10–2.5) and fine particle (PM2.5–0.2) concentrations in greater Boston, USA. Positive matrix factorization (PMF) identified six PM10–2.5 sources (exhaust, road salt, brake wear, regional pollution, road dust resuspension and tyre-road abrasion) and seven fine particle sources. The seven PM2.5–0.2 sources include the six PM10–2.5 sources and a source rich in Cr and Ni. Non- exhaust traffic-related sources together accounted for 65.6% and 29.1% of the PM10–2.5 and PM2.5–0.2 mass, respectively. While the respective contributions of exhaust sources were 10.4% and 20.7%. The biggest non-exhaust contributor in the PM10–2.5 was road dust resuspension, accounting for 29.6%, while for the PM2.5–0.2, the biggest non-exhaust source was road-tyre abrasion, accounting for 12.3%. We used stepwise general additive models (sGAMs) and found statistically significant (p < 0.05) effects of temperature, number of vehicles and rush hour periods on exhaust, brake wear, road dust resuspension and road-tyre abrasion with relative importance between 19.1 and 62.2%, 12.5–42.1% and 4.4–42.2% of the sGAM model's explained variability. Speed limit and road type were also important factors for exhaust, road-tyre and brake wear sources. Meteorological variables of wind speed and relative humidity were significantly associated with both coarse and fine road dust resuspension and had a combined relative importance of 38% and 48%. The quantifying results of the factors that influence traffic-related sources can offer key insights to policies aiming to improve near-road air quality.
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•Sources of PM10–2.5 and PM2.5–0.2 were investigated in 90 near-road environments.•Coarse and fine non-exhaust traffic-related sources combined accounted 65.6% and 29.1% respectively.•Stepwise GAM identified ambient and road factors affecting coarse and fine non-exhaust sources.•Temperature, vehicle number and rush-hours influenced all non-exhaust sources.•Road dust resuspension & road-tyre abrasion were influenced by wind speed, relative humidity and vehicle speed.
Traffic-related air pollution is associated with various adverse health effects. In the absence of more complicated exposure assessment techniques, many environmental health studies have used the ...natural logarithm of distance to road as a proxy for traffic-related exposures. However, research validating this proxy and further explaining the spatial patterns and elemental composition of traffic-related particulate matter air pollution remains limited. In this study, we collected air samples using a mobile particle concentrator that allowed for high sample loading from major roadways in the Greater Boston Area. We found that concentrations of Cl, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Sr, Zr, Sn, Ba, and Pb were significantly associated with the natural logarithm of distance to road in coarse particulate matter, and total fine particulate mass concentrations of Al, Ca, Ti, Cr, Mn, Fe, Cu, and Zn were significantly associated with natural logarithm of distance to road in fine particulate matter. Road type (A1 or A2 primary roads or highways versus A3 secondary and connecting roads) was not a significant predictor of any traffic-related elements in particulate matter air pollution. Our results help identify traffic-related elements in particulate matter air pollution and support the use of logarithm of distance to road as a proxy for traffic-related particulate matter air pollution exposure assessment in epidemiological studies.
Asthma is a chronic inflammatory disease that can be difficult to treat due to its complex pathophysiology. Most current drugs focus on controlling the inflammatory process, but are unable to revert ...the changes of tissue remodeling. Human mesenchymal stromal cells (MSCs) are effective at reducing inflammation and tissue remodeling; nevertheless, no study has evaluated the therapeutic effects of extracellular vesicles (EVs) obtained from human adipose tissue-derived MSCs (AD-MSC) on established airway remodeling in experimental allergic asthma.
C57BL/6 female mice were sensitized and challenged with ovalbumin (OVA). Control (CTRL) animals received saline solution using the same protocol. One day after the last challenge, each group received saline, 10
human AD-MSCs, or EVs (released by 10
AD-MSCs). Seven days after treatment, animals were anesthetized for lung function assessment and subsequently euthanized. Bronchoalveolar lavage fluid (BALF), lungs, thymus, and mediastinal lymph nodes were harvested for analysis of inflammation. Collagen fiber content of airways and lung parenchyma were also evaluated.
In OVA animals, AD-MSCs and EVs acted differently on static lung elastance and on BALF regulatory T cells, CD3
CD4
T cells, and pro-inflammatory mediators (interleukin IL-4, IL-5, IL-13, and eotaxin), but similarly reduced eosinophils in lung tissue, collagen fiber content in airways and lung parenchyma, levels of transforming growth factor-β in lung tissue, and CD3
CD4
T cell counts in the thymus. No significant changes were observed in total cell count or percentage of CD3
CD4
T cells in the mediastinal lymph nodes.
In this immunocompetent mouse model of allergic asthma, human AD-MSCs and EVs effectively reduced eosinophil counts in lung tissue and BALF and modulated airway remodeling, but their effects on T cells differed in lung and thymus. EVs may hold promise for asthma; however, further studies are required to elucidate the different mechanisms of action of AD-MSCs versus their EVs.
Distal slope and basin depositional systems in deep waters of the Pará‐Maranhão Basin, Equatorial Brazil, are investigated using a high‐resolution 3D seismic volume, borehole data and multispectral ...satellite imagery. A Neogene calciclastic submarine fan and a series of channel‐levee systems are analysed at water depths of 100–3,500 m. Channel‐levee systems have sinuous and straight morphologies and are of different sizes. Their origin is related to turbidity flows sourced and funnelled from the carbonate shelf to submarine canyons and gullies, as well as from areas with marked slope instability. A mixed calciclastic‐siliciclastic sediment input is recognised with autochthonous calcarenites and calcilutites comprising the bulk of sediment on the mid and outer continental shelf. Minor amounts of siliciclastic sediment sourced from small rivers occur on the inner shelf. Sedimentation processes of a distally steepened carbonate ramp are discussed considering a general depositional setting dominated by fluctuations in relative sea‐level. Cross‐sectional and planar parameters of mixed calciclastic‐siliciclastic channel‐levee systems are compared to their siliciclastic counterparts. Morphological results show similarities between calciclastic and siliciclastic channel‐levee systems. As a corollary, three types of channel‐levee systems are described: (a) channels related to calciclastic submarine fans, (b) low‐sinuosity, aggradational channels, and (c) high‐sinuosity channels.
Channel‐levee systems are found in deep and ultra‐deep waters of Equatorial Brazil with a mixed calciclastic‐siliciclastic depositional system.
Purpose
To investigate the incidence and risk factors for oral mucositis (OM) in patients with childhood cancer undergoing chemotherapy.
Methods
Eight hundred and twenty-nine cycles of chemotherapy ...were evaluated in 112 patients with childhood cancer undergoing chemotherapy. Chemotherapy protocol, hematological, hepatic, and renal function parameters were collected and compared to presence and severity of OM, as graded by the World Health Organization (WHO) scale. Patients received counseling on oral hygiene and those who presented with OM (grade ≥1) received photobiomodulation therapy (PBMT).
Results
Age ranged from 0 to 17 years (mean/SD, 8.58 ± 5.05) and fifty-one patients (45.54%) were females. The most common baseline diseases were leukemia (51%) followed by sarcomas (23%) and lymphomas (18%). Eight hundred and twenty-nine cycles of chemotherapy were evaluated, and OM was diagnosed in 527 cycles (63.57%). Higher incidence and severity of OM was observed in protocols using high-dose methotrexate (MTX-HD), MTX-HD cyclophosphamide/doxorubicin combination, and MTX-HD combined with cyclophosphamide (
p
<0.001). Patients with severe OM had lower levels of leukocytes (
p
= 0.003), hemoglobin (
p
= 0.005), platelets (
p
= 0.034), and higher levels of total bilirubin (
p
= 0.027), alanine aminotransferase (ALT) (
p
= 0.001), and creatinine (
p
= 0.007).
Conclusion
The study contributes to the elucidation of the risk factors for OM in pediatric cancer patients. Chemotherapy protocols using MTX-HD, MTX-HD associated with doxorubicin and cyclophosphamide, and MTX-HD and cyclophosphamide a have higher incidence of severe grades of OM. Other toxicities such as hematological, hepatic, and renal also developed in patients with OM.
The effects of initial rift inversion over the geometry of a far-foreland intracratonic fold-and-thrust belt are investigated. A total of 25 seismic reflection lines and stratigraphic data from 9 ...wells are used in association to digital elevation and field geological data, to investigate the geometric relationship between shallow thrust development and initial positive inversion of buried rift faults in a cratonic environment, where inversion tectonics is not common. The study case is conducted in the meeting region of the opposed-verging Brasília and Araçuaí foreland fold-and-thrust Neoproterozoic belts, located in central Brazil, formed in the first stages of West Gondwana amalgamation. Seismic reflection sections are used to map buried paleorift faults and trust ramps. The best 5 sections are also interpreted in detail in terms of fold and thrust geometry and their relationship to the inverted rifts is analyzed. They show high correlation between shallow fold-and-thrust geometry and the shortening of synrift strata, caused by rift inversion. Results indicate that initial positive rift fault reactivation exerts a determinant control over the locus of thrust ramp nucleation, by causing syn-rift strata to overfold and drape fold. The passive folding propagates upwards forming gentle folds in the décollement plane, where thrust ramps tend to nucleate. Back-thrust-forethrust pairs tend to form over elevated horsts, where higher topographic plateaus are preserved. Multiple thrusting and lower relief occur over buried rifts with multiple inverted faults. Strata over non-rifted basement remain practically unaffected by thrusting and folding. Moreover, the development of thrust salients and recesses are demonstrated to be conditioned by the morphology of buried rifts. The study also contributes with a more precise mapping of the buried rift system and thrust system in the area, and brings new insights about the structural evolution of the Brasiliano-Pan Africano orogeny affecting the São Francisco craton basement and covers.
•Initial paleorift inversion detected in intracratonic setting.•Thrust ramps nucleate where paleorift inversion folds décollement.•Strain channeling within paleorift results in thrust curvature.•Thrust-related breccia occurs under thrust-ramp, on thrust terminations.•Paleorift initial inversion influences geomorphological evolution.
The aim of this study was to investigate, in a well-controlled experimental environment, whether air pollution from an urban center would affect inflammatory and cardiorespiratory responses during ...prolonged moderate exercise (i.e., 90 min). Ten healthy men performed two experimental trials under filtered and polluted air, inside an environmental chamber located in Sao Paulo downtown, Brazil. Blood samples were obtained at rest, 30, 60, and 90 min of the exercise to determine the serum cytokines concentration, while arterial pressure was recorded immediately after the exercise. The serum cytokines were not altered until 60 min of exercise for both conditions (P > 0.05). Otherwise, at 90 min of exercise, the IL-6 (P = 0.047) and vascular endothelial growth factor (VEGF) (P = 0.026) were significantly higher and IL-10 tended to decrease (P = 0.061) in polluted air condition compared to filtered air condition. In addition, both systolic (P = 0.031) and diastolic (P = 0.009) arterial pressure were higher in polluted air condition than filtered air condition. These findings demonstrate that the exercise of longer duration (i.e., 90 min), but not of shorter duration (i.e., <60 min), performed in vehicular air pollution condition results in pronounced pro-inflammatory and increased arterial pressure responses.
•Effects of air pollution during exercise seem to be dependent on exercise duration.•Air pollution during long duration exercise might increase post arterial pressure.•Systemic inflammation occurs after long exercise under air pollution exposure.•Distance should be considered in active transportation under air pollution exposure.
Asthma represents one of the leading chronic diseases worldwide and causes a high global burden of death and disability. In asthmatic patients, the exacerbation and chronification of the inflammatory ...response are often related to a failure in the resolution phase of inflammation. We reviewed the role of the main arachidonic acid (AA) specialized pro-resolving mediators (SPMs) in the resolution of chronic lung inflammation of asthmatics. AA is metabolized by two classes of enzymes, cyclooxygenases (COX), which produce prostaglandins (PGs) and thromboxanes, and lypoxygenases (LOX), which form leukotrienes and lipoxins (LXs). In asthma, two primary pro-resolving derived mediators from COXs are PGE
and the cyclopentenone prostaglandin15-Deoxy-Delta-12,14-PGJ
(15d-PGJ
) while from LOXs are the LXA
and LXB
. In different models of asthma, PGE
, 15d-PGJ
, and LXs reduced lung inflammation and remodeling. Furthermore, these SPMs inhibited chemotaxis and function of several inflammatory cells involved in asthma pathogenesis, such as eosinophils, and presented an antiremodeling effect in airway epithelial, smooth muscle cells and fibroblasts
. In addition, PGE
, 15d-PGJ
, and LXs are all able to induce macrophage reprogramming to an alternative M2 pro-resolving phenotype
and
. Although PGE
and LXA
showed some beneficial effects in asthmatic patients, there are limitations to their clinical use, since PGE
caused side effects, while LXA
presented low stability. Therefore, despite the strong evidence that these AA-derived SPMs induce resolution of both inflammatory response and tissue remodeling in asthma, safer and more stable analogs must be developed for further clinical investigation of their application in asthma treatment.
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