scholarly journals Large Contributions from Biogenic Monoterpenes and Sesquiterpenes to Organic Aerosol in the Southeastern United States

2018 ◽  
Author(s):  
Lu Xu ◽  
Havala O. T. Pye ◽  
Jia He ◽  
Yunle Chen ◽  
Benjamin N. Murphy ◽  
...  
Keyword(s):  
Field Experiments ◽  
Field Studies ◽  
Organic Aerosol ◽  
Atmospheric Model ◽  
Average Concentration ◽  
Mass Spectrometry Data ◽  
World Health ◽  
Atmospheric Conditions ◽  
Considerable Uncertainty ◽  
Health Organization

Abstract. Atmospheric organic aerosol (OA) has important impacts on climate and human health but its sources remain poorly understood. Biogenic monoterpenes and sesquiterpenes are critical precursors of OA. The OA generation from these precursors predicted by models has considerable uncertainty owing to a lack of appropriate observations as constraints. Here, we perform novel lab-in-the-field experiments, which allow us to study OA formation under realistic atmospheric conditions and offer a connection between laboratory and field studies. Based on the lab-in-the-field experimental approach and positive matrix factorization analysis on aerosol mass spectrometry data, we provide a measure of OA from monoterpenes and sesquiterpenes in the southeastern U.S. Further, we use an upgraded atmospheric model and reproduce the measured OA concentration from monoterpenes and sesquiterpenes at multiple sites in the southeastern U.S., building confidence in the observed attribution of monoterpene SOA. We show that the annual average concentration of OA from monoterpenes and sesquiterpenes in the southeastern U.S. is ~ 2.1 µg m−3. This amount is substantially higher than represented in current regional models and accounts for 21 % of World Health Organization PM2.5 standard, indicating a significant contributor of environmental risk to the 77 million habitants in the southeastern U.S.

scholarly journals Experimental and model estimates of the contributions from biogenic monoterpenes and sesquiterpenes to secondary organic aerosol in the southeastern United States

2018 ◽  
Vol 18 (17) ◽  
pp. 12613-12637 ◽  
Author(s):  
Lu Xu ◽  
Havala O. T. Pye ◽  
Jia He ◽  
Yunle Chen ◽  
Benjamin N. Murphy ◽  
...  
Keyword(s):  
Field Experiments ◽  
Secondary Organic Aerosol ◽  
Ground Level ◽  
Ambient Air ◽  
Organic Aerosol ◽  
Atmospheric Model ◽  
Average Concentration ◽  
Aerosol Mass ◽  
Southeastern Us ◽  
Annual Average Concentration

Abstract. Atmospheric organic aerosol (OA) has important impacts on climate and human health but its sources remain poorly understood. Biogenic monoterpenes and sesquiterpenes are important precursors of secondary organic aerosol (SOA), but the amounts and pathways of SOA generation from these precursors are not well constrained by observations. We propose that the less-oxidized oxygenated organic aerosol (LO-OOA) factor resolved from positive matrix factorization (PMF) analysis on aerosol mass spectrometry (AMS) data can be used as a surrogate for fresh SOA from monoterpenes and sesquiterpenes in the southeastern US. This hypothesis is supported by multiple lines of evidence, including lab-in-the-field perturbation experiments, extensive ambient ground-level measurements, and state-of-the-art modeling. We performed lab-in-the-field experiments in which the ambient air is perturbed by the injection of selected monoterpenes and sesquiterpenes, and the subsequent SOA formation is investigated. PMF analysis on the perturbation experiments provides an objective link between LO-OOA and fresh SOA from monoterpenes and sesquiterpenes as well as insights into the sources of other OA factors. Further, we use an upgraded atmospheric model and show that modeled SOA concentrations from monoterpenes and sesquiterpenes could reproduce both the magnitude and diurnal variation of LO-OOA at multiple sites in the southeastern US, building confidence in our hypothesis. We estimate the annual average concentration of SOA from monoterpenes and sesquiterpenes in the southeastern US to be roughly 2 µg m−3.

scholarly journals Improving the Role and Contribution of Pharmacokinetic Analyses in Antimalarial Drug Clinical Trials

2014 ◽  
Vol 58 (10) ◽  
pp. 5643-5649 ◽  
Author(s):  
Katherine Kay ◽  
Eva Maria Hodel ◽  
Ian M. Hastings
Keyword(s):  
Antimalarial Drug ◽  
Theoretical Data ◽  
Drug Efficacy ◽  
Cost Effective ◽  
Field Studies ◽  
World Health ◽  
Efficacy Trials ◽  
Drug Concentrations ◽  
Health Organization ◽  
Study Designs

ABSTRACTIt is now World Health Organization (WHO) policy that drug concentrations on day 7 be measured as part of routine assessment in antimalarial drug efficacy trials. The rationale is that this single pharmacological measure serves as a simple and practical predictor of treatment outcome for antimalarial drugs with long half-lives. Herein we review theoretical data and field studies and conclude that the day 7 drug concentration (d7c) actually appears to be a poor predictor of therapeutic outcome. This poor predictive capability combined with the fact that many routine antimalarial trials will have few or no failures means that there appears to be little justification for this WHO recommendation. Pharmacological studies have a huge potential to improve antimalarial dosing, and we propose study designs that use more-focused, sophisticated, and cost-effective ways of generating these data than the mass collection of single d7c concentrations.

scholarly journals Molecular profiling predicts meningioma recurrence and reveals loss of DREAM complex repression in aggressive tumors

2019 ◽  
Vol 116 (43) ◽  
pp. 21715-21726 ◽  
Author(s):  
Akash J. Patel ◽  
Ying-Wooi Wan ◽  
Rami Al-Ouran ◽  
Jean-Pierre Revelli ◽  
Maria F. Cardenas ◽  
...  
Keyword(s):  
World Health ◽  
Sequencing Data ◽  
Histopathological Classification ◽  
Considerable Uncertainty ◽  
Cell Cycle Activation ◽  
Targeted Treatments ◽  
Meningioma Recurrence ◽  
Aggressive Tumors ◽  
Biochemical Analyses ◽  
Health Organization

Meningiomas account for one-third of all primary brain tumors. Although typically benign, about 20% of meningiomas are aggressive, and despite the rigor of the current histopathological classification system there remains considerable uncertainty in predicting tumor behavior. Here, we analyzed 160 tumors from all 3 World Health Organization (WHO) grades (I through III) using clinical, gene expression, and sequencing data. Unsupervised clustering analysis identified 3 molecular types (A, B, and C) that reliably predicted recurrence. These groups did not directly correlate with the WHO grading system, which classifies more than half of the tumors in the most aggressive molecular type as benign. Transcriptional and biochemical analyses revealed that aggressive meningiomas involve loss of the repressor function of the DREAM complex, which results in cell-cycle activation; only tumors in this category tend to recur after full resection. These findings should improve our ability to predict recurrence and develop targeted treatments for these clinically challenging tumors.

scholarly journals Sources and atmospheric dynamics of organic aerosol in New Delhi, India: insights from receptor modeling

2020 ◽  
Vol 20 (2) ◽  
pp. 735-752 ◽  
Author(s):  
Sahil Bhandari ◽  
Shahzad Gani ◽  
Kanan Patel ◽  
Dongyu S. Wang ◽  
Prashant Soni ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Chemical Characterization ◽  
Organic Aerosol ◽  
Receptor Modeling ◽  
World Health ◽  
Aerosol Composition ◽  
Time Resolved ◽  
Online Measurements ◽  
Using Data ◽  
Health Organization

Abstract. Delhi, India, is the second most populated city in the world and routinely experiences some of the highest particulate matter concentrations of any megacity on the planet, posing acute challenges to public health (World Health Organization, 2018). However, the current understanding of the sources and dynamics of PM pollution in Delhi is limited. Measurements at the Delhi Aerosol Supersite (DAS) provide long-term chemical characterization of ambient submicron aerosol in Delhi, with near-continuous online measurements of aerosol composition. Here we report on source apportionment based on positive matrix factorization (PMF), conducted on 15 months of highly time-resolved speciated submicron non-refractory PM1 (NR-PM1) between January 2017 and March 2018. We report on seasonal variability across four seasons of 2017 and interannual variability using data from the two winters and springs of 2017 and 2018. We show that a modified tracer-based organic component analysis provides an opportunity for a real-time source apportionment approach for organics in Delhi. Phase equilibrium modeling of aerosols using the extended aerosol inorganics model (E-AIM) predicts equilibrium gas-phase concentrations and allows evaluation of the importance of the ventilation coefficient (VC) and temperature in controlling primary and secondary organic aerosol. We also find that primary aerosol dominates severe air pollution episodes, and secondary aerosol dominates seasonal averages.

scholarly journals Comparison of mice’ sperm parameters exposed to some hazardous physical agents

2021 ◽  
Vol 36 (3) ◽  
pp. e2021013
Author(s):  
Mohammad-Bagher Abdollahi ◽  
Somayeh Farhang Dehghan ◽  
Faezeh Abasi Balochkhaneh ◽  
Manouchehr Ahmadi Moghadam ◽  
Hamzeh Mohammadi
Keyword(s):  
Sperm Count ◽  
Semen Analysis ◽  
Field Studies ◽  
Sperm Parameters ◽  
World Health ◽  
Control Group ◽  
Normal Morphology ◽  
Progressive Motility ◽  
Noise Vibration ◽  
Health Organization

The present study was aimed to compare the effects of exposure to noise, vibration, lighting, and microwave on male mice’ sperm parameters. The mice were randomly assigned to five groups of eight, which comprised of the unexposed group and exposure groups including the lighting (1000 lux), noise (100 dB(A)), vibration (acceleration of 1.2 m/s2) and microwave (power density of 5 watts). The exposure groups were subjected to the four agents for 8 hours a day, 5 days a week during a 2-week period. Semen analysis were done according to World Health Organization guidelines. The highest significant mean difference in sperm count (-1.35×106/mL) had being observed between the microwave group and the control one (P=0.001). The highest difference in immotile percent (25.88 %) had being observed between the noise group and the control one (P=0.001). The highest difference in normal morphology (-27.06 %) observed between the lighting exposure group and the control group (P=0.001). The four agents can cause changes in different sperm parameters, however for definite conclusion; more laboratory and field studies are required. In total, exposure to microwave has had the greatest effect on sperm count and exposure to light has had the greatest effect on normal morphology and non-progressive motility. Moreover, exposure to noise has had the greatest effect on progressive motility and immotile percent, respectively.

scholarly journals Air Pollution with Asbestos Fibers in Some Heavy Traffic Areas of Baghdad

2021 ◽  
pp. 2143-2152
Author(s):  
Nahla Sh. Ajeel ◽  
Nada A. Fleeh ◽  
Matham A. Sultan
Keyword(s):  
Membrane Filter ◽  
Heavy Traffic ◽  
Ambient Air ◽  
Average Concentration ◽  
World Health ◽  
Low Flow ◽  
Cellulose Ester ◽  
Industrial Sites ◽  
Asbestos Fibers ◽  
Health Organization

     This research was conducted to measure the levels of asbestos fibers in the air of some dense sites of Baghdad city, which were monitored in autumn 2019. Samples collection was conducted via directing air flow to a mixed cellulose ester membrane filter mounted on an open‑faced filter holder using sniffer with a low flow sampling pump. Air samples were collected from four studied areas selected in some high traffic areas of Baghdad city, two of them were located in Karkh (Al-Bayaa and Al-Shurta tunnel) and two in Rusafa (Al-Jadriya and Al-Meshin complex), then analyzed to determine concentrations of asbestos. Measuring of levels of asbestos fibers on the filters was carried out via using scanning electron microscope SEM together with  an energy dispersive X‑ray system (EDS). The results showed that the lowest level was recorded in Al-Jadriya intersection (0.0352 fiber/ml), while the maximum concentration was in Al-Bayaa (0.156 f/ml). Asbestos average concentration in the ambient air of the four studied areas was 0.0718 f/ml, which exceeded the standards of world health organization (WHO) for air which is equal to 0.0022 f/ml. This may be due to the presence of crowded traffic and the occurrence of industries near the city. Therefore, plans such as management of traffic, changing locations of industrial sites, and products substitution can be effective in minimizing the concentrations of airborne fibers.

scholarly journals Standard review and update for tropical comfort shift of the built environment

2018 ◽  
Vol 67 ◽  
pp. 04013 ◽  
Author(s):  
FX Teddy Badai Samodra ◽  
Irvansyah ◽  
Collinthia Erwindi
Keyword(s):  
Built Environment ◽  
Thermal Comfort ◽  
Field Study ◽  
Building Design ◽  
Field Studies ◽  
Tropical Climate ◽  
National Standard ◽  
World Health ◽  
Comparison Results ◽  
Health Organization

The urban building standards recommend adaptable shift on heat and noise criteria as the main issues related to the high-density environment. The previous studies relating to building thermal comfort provided the comparison results between the past and recent conditions. This study reviews the guidelines and regulations of international standard, overseas countries, and specific region of tropical climate research in Indonesia. The evaluation is focused on tropical climate in order to reach the accurate thermal comfort and noise criteria comparison for Indonesia. Furthermore, the field study of the 71 of the tropical built environment respondents was also conducted in order to update and compare to the existing standards. The review results show that compared to 17°C to 31°C thermal comfort range from the World Health Organization, the tropical thermal comfort should be determined with a range of 29.3°C to 31°C. Based on the field studies, for lowland is formulated by 1.4x+29.3 and in highland is 1.5x+29.3 as two representative regions of the tropical environment. For noise criteria, some countries set the policy for determining noise limits which has the same value between day and night condition as the result of the constant number of noise source with the similar level of annoyance. Based on the field study, this study updates the noise criteria which the denser environment, lowland, has limits of noise in 49.9 dBA when in highland is 47.8 dBA. Both of them are lower than 55 dBA of Indonesian Standard. Noise perception by occupants in nighttime shows that both in the lowland and in the highland, the vote is lower than daytime. The noise limits are 45.9 dBA and 40.0 dBA for lowland and highland, respectively. In general, the updated standard completes the existing and the detail of Indonesia national standard and the will be useful to guide the tropical building design.

Environmental Effects of Aluminum Used in Water Treatment Plants of Rio de Janeiro State, Brazil

1994 ◽  
Vol 29 (4) ◽  
pp. 571-580
Author(s):  
Jose M. Azcue ◽  
Olaf Malam ◽  
Wolfgang G. Pfeiffer
Keyword(s):  
Water Treatment ◽  
Rio De Janeiro ◽  
River System ◽  
Average Concentration ◽  
World Health ◽  
Water Treatment Plants ◽  
Alum Sludge ◽  
Health Organization ◽  
The City ◽  
Janeiro State

Abstract The effect of the extended use of alum on the concentration of aluminum in water treatment was investigated. Water from the Paraiba do Sul-Guandu River (PSR-GR) system, collected after conventional treatment, was analyzed from the six water treatment plants (WTPs). One of the WTPs, the Guandu WTP, supplies water to the city of Rio de Janeiro (11 million inhabitants) with a flow of 40 m3/s. The concentrations of aluminum found were near and sometimes over the values recommended by the World Health Organization (200 µg/L), with an average concentration of 306 µg/L, reaching seasonally maximum values of 877 µg/L at the WTP and 2,100 µg/L in household taps. The discharge of alum sludge back to the river system is the predominant pathway in the aluminum cycling in the study area, followed by sedimentation and enhanced availability to the biota.

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