LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 59

Search options

  1. Article ; Online: Always Lost but Never Forgotten: Gas-Phase Wall Losses Are Important in All Teflon Environmental Chambers.

    Krechmer, Jordan E / Day, Douglas A / Jimenez, Jose L

    Environmental science & technology

    2020  Volume 54, Issue 20, Page(s) 12890–12897

    Abstract: Yields of secondary organic aerosol (SOA) formation from oxidation of volatile organic compounds are measured in laboratory chambers and then applied in regional and global models. Gas-phase losses to large Teflon-walled environmental chambers have been ... ...

    Abstract Yields of secondary organic aerosol (SOA) formation from oxidation of volatile organic compounds are measured in laboratory chambers and then applied in regional and global models. Gas-phase losses to large Teflon-walled environmental chambers have been recently shown to reduce SOA yields. Historically, most chambers have operated in batch mode. Increasingly, however, continuous flow (CF) mode is being used, in which reactants and products are continuously introduced and exhausted from the chamber. Recent literature reports indicate a belief that SOA yields measured in CF chambers are not affected by gas-phase wall losses (GWL). Here, we use an experimentally-constrained box model to show that gas-phase wall losses impact both types of chambers when run under similar conditions. We find CF experiments do mitigate some effects of gas-phase wall losses after long (>2 days) experiment run times, but they have significant losses for typical literature experiment times of 1 day. However, this mitigation phenomenon is an experiment- and mechanism-dependent, and GWL still affects the absolute SOA yield. Finally, we show that at condensation sink values higher than the wall loss rate a lack of change in yield vs seed surface area does not necessarily indicate whether GWL affects the experiment and does not suggest the magnitude.
    MeSH term(s) Aerosols/analysis ; Air Pollutants ; Oxidation-Reduction ; Polytetrafluoroethylene ; Volatile Organic Compounds/analysis
    Chemical Substances Aerosols ; Air Pollutants ; Volatile Organic Compounds ; Polytetrafluoroethylene (9002-84-0)
    Language English
    Publishing date 2020-09-30
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ISSN 1520-5851
    ISSN (online) 1520-5851
    DOI 10.1021/acs.est.0c03381
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article ; Online: The influence of personal care products on ozone-skin surface chemistry.

    Morrison, Glenn / Eftekhari, Azin / Fan, Aixing / Majluf, Francesca / Krechmer, Jordan E

    PloS one

    2022  Volume 17, Issue 9, Page(s) e0268263

    Abstract: Personal care products are increasingly being marketed to protect skin from the potentially harmful effects of air pollution. Here, we experimentally measure ozone deposition rates to skin and the generation rates and yields of oxidized products from ... ...

    Abstract Personal care products are increasingly being marketed to protect skin from the potentially harmful effects of air pollution. Here, we experimentally measure ozone deposition rates to skin and the generation rates and yields of oxidized products from bare skin and skin coated with various lotion formulations. Lotions reduced the ozone flux to the skin surface by 12% to 25%; this may be due to dilution of reactive skin lipids with inert lotion compounds or by reducing ozone diffusivity within the resulting mixture. The yields of volatile squalene oxidation products were 25% to 70% lower for a commercial sunscreen and for a base lotion with an added polymer or with antioxidants. Lower yields are likely due to competitive reactions of ozone with lotion ingredients including some ingredients that are not intended to be ozone sinks. The dynamics of the emissions of squalene ozonation product 6 methyl-2-heptenone (6MHO) suggest that lotions can dramatically reduce the solubility of products in the skin film. While some lotions appear to reduce the rate of oxidation of squalene by ozone, this evidence does not yet demonstrate that the lotions reduce the impact of air pollution on skin health.
    MeSH term(s) Emollients ; Lipids ; Ozone ; Polymers ; Squalene ; Sunscreening Agents
    Chemical Substances Emollients ; Lipids ; Polymers ; Sunscreening Agents ; Ozone (66H7ZZK23N) ; Squalene (7QWM220FJH)
    Language English
    Publishing date 2022-09-29
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2267670-3
    ISSN 1932-6203 ; 1932-6203
    ISSN (online) 1932-6203
    ISSN 1932-6203
    DOI 10.1371/journal.pone.0268263
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article ; Online: Quantification of natural gas and other hydrocarbons from production sites in northern West Virginia using tracer flux ratio methodology.

    Daube, Conner / Herndon, Scott C / Krechmer, Jordan E / Johnson, Derek / Clark, Nigel / Footer, Tracey L / Thoma, Eben D

    Atmospheric Environment: X

    2023  Volume 19, Page(s) 1–8

    Abstract: Tracer flux ratio (TFR) methodology performed downwind of 15 active oil and natural gas production sites in Ohio County, West Virginia sought to quantify air pollutant emissions over two weeks in April 2018. In coordination with a production company, ... ...

    Abstract Tracer flux ratio (TFR) methodology performed downwind of 15 active oil and natural gas production sites in Ohio County, West Virginia sought to quantify air pollutant emissions over two weeks in April 2018. In coordination with a production company, sites were randomly selected depending on wind forecasts and nearby road access. Methane (CH
    Language English
    Publishing date 2023-04-17
    Publishing country England
    Document type Journal Article
    ISSN 2590-1621
    ISSN (online) 2590-1621
    DOI 10.1016/j.aeaoa.2023.100220
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Article ; Online: Yields and Variability of Ozone Reaction Products from Human Skin.

    Morrison, Glenn C / Eftekhari, Azin / Majluf, Francesca / Krechmer, Jordan E

    Environmental science & technology

    2020  Volume 55, Issue 1, Page(s) 179–187

    Abstract: The skin of 20 human participants was exposed to ∼110 ppb ... ...

    Abstract The skin of 20 human participants was exposed to ∼110 ppb O
    MeSH term(s) Air Pollution, Indoor/analysis ; Humans ; Lipids ; Ozone/analysis ; Skin/chemistry ; Squalene
    Chemical Substances Lipids ; Ozone (66H7ZZK23N) ; Squalene (7QWM220FJH)
    Language English
    Publishing date 2020-12-18
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1520-5851
    ISSN (online) 1520-5851
    DOI 10.1021/acs.est.0c05262
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article ; Online: Influence of the NO/NO

    Nihill, Kevin J / Ye, Qing / Majluf, Francesca / Krechmer, Jordan E / Canagaratna, Manjula R / Kroll, Jesse H

    Environmental science & technology

    2021  Volume 55, Issue 10, Page(s) 6594–6601

    Abstract: Organic oxidation reactions in the atmosphere can be challenging to parse due to the large number of branching points within each molecule's reaction mechanism. This complexity can complicate the attribution of observed effects to a particular chemical ... ...

    Abstract Organic oxidation reactions in the atmosphere can be challenging to parse due to the large number of branching points within each molecule's reaction mechanism. This complexity can complicate the attribution of observed effects to a particular chemical pathway. In this study, we simplify the chemistry of atmospherically relevant systems, and particularly the role of NO
    MeSH term(s) Aerosols ; Atmosphere ; Nitrites ; Nitrogen Dioxide ; Oxidation-Reduction
    Chemical Substances Aerosols ; Nitrites ; alkyl nitrite ; Nitrogen Dioxide (S7G510RUBH)
    Language English
    Publishing date 2021-04-26
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ISSN 1520-5851
    ISSN (online) 1520-5851
    DOI 10.1021/acs.est.0c07621
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article: Always Lost but Never Forgotten: Gas-Phase Wall Losses Are Important in All Teflon Environmental Chambers

    Krechmer, Jordan E / Day, Douglas A / Jimenez, Jose L

    Environmental science & technology. 2020 Sept. 15, v. 54, no. 20

    2020  

    Abstract: Yields of secondary organic aerosol (SOA) formation from oxidation of volatile organic compounds are measured in laboratory chambers and then applied in regional and global models. Gas-phase losses to large Teflon-walled environmental chambers have been ... ...

    Abstract Yields of secondary organic aerosol (SOA) formation from oxidation of volatile organic compounds are measured in laboratory chambers and then applied in regional and global models. Gas-phase losses to large Teflon-walled environmental chambers have been recently shown to reduce SOA yields. Historically, most chambers have operated in batch mode. Increasingly, however, continuous flow (CF) mode is being used, in which reactants and products are continuously introduced and exhausted from the chamber. Recent literature reports indicate a belief that SOA yields measured in CF chambers are not affected by gas-phase wall losses (GWL). Here, we use an experimentally-constrained box model to show that gas-phase wall losses impact both types of chambers when run under similar conditions. We find CF experiments do mitigate some effects of gas-phase wall losses after long (>2 days) experiment run times, but they have significant losses for typical literature experiment times of 1 day. However, this mitigation phenomenon is an experiment- and mechanism-dependent, and GWL still affects the absolute SOA yield. Finally, we show that at condensation sink values higher than the wall loss rate a lack of change in yield vs seed surface area does not necessarily indicate whether GWL affects the experiment and does not suggest the magnitude.
    Keywords aerosols ; environmental science ; models ; oxidation ; polytetrafluoroethylene ; surface area ; technology ; volatile organic compounds
    Language English
    Dates of publication 2020-0915
    Size p. 12890-12897.
    Publishing place American Chemical Society
    Document type Article
    Note NAL-AP-2-clean
    ISSN 1520-5851
    DOI 10.1021/acs.est.0c03381
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  7. Article: Automating methods for estimating metabolite volatility.

    Meredith, Laura K / Ledford, S Marshall / Riemer, Kristina / Geffre, Parker / Graves, Kelsey / Honeker, Linnea K / LeBauer, David / Tfaily, Malak M / Krechmer, Jordan

    Frontiers in microbiology

    2023  Volume 14, Page(s) 1267234

    Abstract: The volatility of metabolites can influence their biological roles and inform optimal methods for their detection. Yet, volatility information is not readily available for the large number of described metabolites, limiting the exploration of volatility ... ...

    Abstract The volatility of metabolites can influence their biological roles and inform optimal methods for their detection. Yet, volatility information is not readily available for the large number of described metabolites, limiting the exploration of volatility as a fundamental trait of metabolites. Here, we adapted methods to estimate vapor pressure from the functional group composition of individual molecules (SIMPOL.1) to predict the gas-phase partitioning of compounds in different environments. We implemented these methods in a new open pipeline called
    Language English
    Publishing date 2023-12-14
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2587354-4
    ISSN 1664-302X
    ISSN 1664-302X
    DOI 10.3389/fmicb.2023.1267234
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  8. Article ; Online: Molecular mechanism for rapid autoxidation in α-pinene ozonolysis.

    Iyer, Siddharth / Rissanen, Matti P / Valiev, Rashid / Barua, Shawon / Krechmer, Jordan E / Thornton, Joel / Ehn, Mikael / Kurtén, Theo

    Nature communications

    2021  Volume 12, Issue 1, Page(s) 878

    Abstract: Aerosol affects Earth's climate and the health of its inhabitants. A major contributor to aerosol formation is the oxidation of volatile organic compounds. Monoterpenes are an important class of volatile organic compounds, and recent research demonstrate ...

    Abstract Aerosol affects Earth's climate and the health of its inhabitants. A major contributor to aerosol formation is the oxidation of volatile organic compounds. Monoterpenes are an important class of volatile organic compounds, and recent research demonstrate that they can be converted to low-volatility aerosol precursors on sub-second timescales following a single oxidant attack. The α-pinene + O
    Language English
    Publishing date 2021-02-09
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-021-21172-w
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Article ; Online: Laboratory Investigation of Renoxification from the Photolysis of Inorganic Particulate Nitrate.

    Shi, Qianwen / Tao, Ye / Krechmer, Jordan E / Heald, Colette L / Murphy, Jennifer G / Kroll, Jesse H / Ye, Qing

    Environmental science & technology

    2021  Volume 55, Issue 2, Page(s) 854–861

    Abstract: Nitrogen oxides ( ... ...

    Abstract Nitrogen oxides (NO
    MeSH term(s) Aerosols ; Laboratories ; Nitrates ; Nitric Acid ; Nitrogen Oxides/analysis ; Photolysis
    Chemical Substances Aerosols ; Nitrates ; Nitrogen Oxides ; Nitric Acid (411VRN1TV4)
    Language English
    Publishing date 2021-01-04
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ISSN 1520-5851
    ISSN (online) 1520-5851
    DOI 10.1021/acs.est.0c06049
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Book ; Online: Versatile soil gas concentration and isotope monitoring

    Gil-Loaiza, Juliana / Roscioli, Joseph R. / Shorter, Joanne H. / Volkmann, Till H. M. / Ng, Wei-Ren / Krechmer, Jordan E. / Meredith, Laura K.

    eISSN: 1726-4189

    optimization and integration of novel soil gas probes with online trace gas detection

    2022  

    Abstract: Gas concentrations and isotopic signatures can unveil microbial metabolisms and their responses to environmental changes in soil. Currently, few methods measure in situ soil trace gases such as the products of nitrogen and carbon cycling or volatile ... ...

    Abstract Gas concentrations and isotopic signatures can unveil microbial metabolisms and their responses to environmental changes in soil. Currently, few methods measure in situ soil trace gases such as the products of nitrogen and carbon cycling or volatile organic compounds (VOCs) that constrain microbial biochemical processes like nitrification, methanogenesis, respiration, and microbial communication. Versatile trace gas sampling systems that integrate soil probes with sensitive trace gas analyzers could fill this gap with in situ soil gas measurements that resolve spatial (centimeters) and temporal (minutes) patterns. We developed a system that integrates new porous and hydrophobic sintered polytetrafluoroethylene (sPTFE) diffusive soil gas probes that non-disruptively collect soil gas samples with a transfer system to direct gas from multiple probes to one or more central gas analyzer(s) such as laser and mass spectrometers. Here, we demonstrate the feasibility and versatility of this automated multiprobe system for soil gas measurements of isotopic ratios of nitrous oxide ( δ 18 O, δ 15 N, and the 15 N site preference of N 2 O), methane, carbon dioxide ( δ 13 C), and VOCs. First, we used an inert silica matrix to challenge probe measurements under controlled gas conditions. By changing and controlling system flow parameters, including the probe flow rate, we optimized recovery of representative soil gas samples while reducing sampling artifacts on subsurface concentrations. Second, we used this system to provide a real-time window into the impact of environmental manipulation of irrigation and soil redox conditions on in situ N 2 O and VOC concentrations. Moreover, to reveal the dynamics in the stable isotope ratios of N 2 O (i.e., 14 N 14 N 16 O, 14 N 15 N 16 O, 15 N 14 N 16 O, and 14 N 14 N 18 O), we developed a new high-precision laser spectrometer with a reduced sample volume demand. Our integrated system – a tunable infrared laser direct absorption spectrometry (TILDAS) in parallel with Vocus proton transfer reaction mass spectrometry (PTR-MS), in line with sPTFE soil gas probes – successfully quantified isotopic signatures for N 2 O, CO 2 , and VOCs in real time as responses to changes in the dry–wetting cycle and redox conditions. Broadening the collection of trace gases that can be monitored in the subsurface is critical for monitoring biogeochemical cycles, ecosystem health, and management practices at scales relevant to the soil system.
    Subject code 333 ; 511
    Language English
    Publishing date 2022-01-10
    Publishing country de
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

To top