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https://www.readbyqxmd.com/read/29468292/compact-devices-for-generation-of-reference-trace-voc-mixtures-a-new-concept-in-assuring-quality-at-chemical-and-biochemical-laboratories
#1
Alessia Demichelis, Céline Pascale, Maricarmen Lecuna, Bernhard Niederhauser, Guido Sassi, Maria Paola Sassi
Volatile organic compounds (VOCs) in gas mixtures at trace level (nmol/mol) are routinely measured by chemical and biochemical laboratories as climate indicators, indoor air quality pollutants from building materials emissions, contaminants in food and beverages, and biomarkers in body fluids (blood, urine, breath) of occupational exposure or human diseases. Current analytical instruments used for measurements are gas chromatographs equipped with various injector and detector configurations. The assurance of measurement quality is done by using a huge amount of certified liquid VOC standard solutions (or gaseous VOC standard cylinders) with multiple dilutions to reach the required trace level...
February 22, 2018: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/29466295/can-plant-defence-mechanisms-provide-new-approaches-for-the-sustainable-control-of-the-two-spotted-spider-mite-tetranychus-urticae
#2
REVIEW
Blas Agut, Victoria Pastor, Josep A Jaques, Victor Flors
Tetranychus urticae ( T. urticae ) Koch is a cosmopolitan, polyphagous mite which causes economic losses in both agricultural and ornamental plants. Some traits of T. urticae hamper its management, including a short life cycle, arrhenotokous parthenogenesis, its haplodiploid sex determination system, and its extraordinary ability to adapt to different hosts and environmental conditions. Currently, the use of chemical and biological control are the major control methods used against this mite. In recent years, some studies have focused on plant defence mechanisms against herbivores...
February 21, 2018: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29465294/occupational-health-risk-assessment-of-volatile-organic-compounds-emitted-from-coke-production-unit-of-a-steel-plant
#3
Fateme Dehghani, Fariborz Omidi, Omidreza Heravizadeh, Saied Barati Chamgordani, Vahid Gharibi, Akbar Sotoudeh Manesh
In this study, cancer and non-cancer risks of exposure to Volatile Organic Compounds (VOCs) in the coke production unit of a steel plant were evaluated. To determine individual exposure to benzene, toluene, xylene, and ethylbenzene (BTEX), personal samples were taken from the breathing zone of workers according to the National Institute for Occupational Safety and Health (NIOSH) 1501. Cancer and non-cancer risk assessment was performed, using United States Environmental Protection Agency (US EPA) methods. Samples analysis showed that concentration of benzene in the energy and biochemistry and benzol refinement sections was higher than occupational exposure limits (OELs)...
February 21, 2018: International Journal of Occupational Safety and Ergonomics: JOSE
https://www.readbyqxmd.com/read/29465005/influence-of-airborne-particulates-on-respiratory-tract-deposition-of-inhaled-toluene-and-naphthalene-in-the-rat
#4
Stephen M Roberts, Annette C Rohr, Vladimir B Mikheev, John Munson, Tara Sabo-Attwood
OBJECTIVE: Most studies report that inhaled volatile and semivolatile organic compounds (VOCs/SVOCs) tend to deposit in the upper respiratory tract, while ultrafine (or near ultrafine) particulate matter (PM) (∼100 nm) reaches the lower airways. The objective of this study was to determine whether carbon particle co-exposure carries VOCs/SVOCs deeper into the lungs where they are deposited. MATERIALS AND METHODS: Male Sprague-Dawley rats were exposed by inhalation (nose-only) to radiolabeled toluene (20 ppm) or naphthalene (20 ppm) on a single occasion for 1 h, with or without concurrent carbon particle exposure (∼5 mg/m3 )...
February 21, 2018: Inhalation Toxicology
https://www.readbyqxmd.com/read/29464601/using-a-multi-method-approach-based-on-soil-radon-deficit-resistivity-and-induced-polarization-measurements-to-monitor-non-aqueous-phase-liquid-contamination-in-two-study-areas-in-italy-and-india
#5
Mauro Castelluccio, Sudha Agrahari, Gabriele De Simone, Francesca Pompilj, Carlo Lucchetti, Debashish Sengupta, Gianfranco Galli, Pierluigi Friello, Pierpaolo Curatolo, Riccardo Giorgi, Paola Tuccimei
Geochemical and geophysical surveys employing radon deficit, resistivity, and induced polarization (IP) measurements were undertaken on soil contaminated with non-aqueous phase liquids (NAPLs) in two different sites in India and in Italy. Radon deficit, validated through the comparison with average soil radon in reference unpolluted areas, shows the extension of contamination in the upper part of the unsaturated aquifers. In site 1 (Italy), the spill is not recent. A residual film of kerosene covers soil grains, inhibiting their chargeability and reducing electrical resistivity difference with background unpolluted areas...
February 20, 2018: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29464255/plasmonic-nose-integrating-the-mof-enabled-molecular-preconcentration-effect-with-a-plasmonic-array-for-recognition-of-molecular-level-volatile-organic-compounds
#6
Charlynn Sher Lin Koh, Hiang Kwee Lee, Xuemei Han, Howard Yi Fan Sim, Xing Yi Ling
Timely detection of toxic vapor is vital for safeguarding people's lives. Herein, we design a plasmonic nose based on a zeolitic imidazolate framework (ZIF)-encapsulated Ag nanocube array for ultratrace recognition of VOC vapor. The plasmonic nose enables in situ adsorption kinetics and recognition of various VOCs at ppm levels, eliminating false positives. Our approach provides a paradigm shift to next-generation, effective and specific gas sensors.
February 21, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29463885/machine-learning-for-the-meta-analyses-of-microbial-pathogens-volatile-signatures
#7
Susana I C J Palma, Ana P Traguedo, Ana R Porteira, Maria J Frias, Hugo Gamboa, Ana C A Roque
Non-invasive and fast diagnostic tools based on volatolomics hold great promise in the control of infectious diseases. However, the tools to identify microbial volatile organic compounds (VOCs) discriminating between human pathogens are still missing. Artificial intelligence is increasingly recognised as an essential tool in health sciences. Machine learning algorithms based in support vector machines and features selection tools were here applied to find sets of microbial VOCs with pathogen-discrimination power...
February 20, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29463782/endogenous-volatile-organic-compounds-in-acute-myeloid-leukemia-origins-and-potential-clinical-applications
#8
Dibyendu Dutta, Ngee S Chong, Seah H Lim
Not unlike many cancer types, acute myeloid leukemia (AML) exhibits many metabolic changes and reprogramming, causing changes in lipid metabolism. Some of the distinct molecular abnormalities associated with AML also modify the metabolic changes. Both processes result in changes in the production of endogenous volatile organic compounds (VOCs). The increasing availability of highly sensitive methods for detecting trace chemicals provides the opportunity to investigate the role of patient-specific VOC finger-prints as biomarkers for detecting early relapse or minimal residual disease (MRD) in AML...
February 21, 2018: Journal of Breath Research
https://www.readbyqxmd.com/read/29462388/the-impact-of-nod2-variants-on-fecal-microbiota-in-crohn-s-disease-and-controls-without-gastrointestinal-disease
#9
Nicholas A Kennedy, Christopher A Lamb, Susan H Berry, Alan W Walker, John Mansfield, Miles Parkes, Rachel Simpkins, Mark Tremelling, Sarah Nutland, Julian Parkhill, Chris Probert, Georgina L Hold, Charlie W Lees
Background/Aims: Current models of Crohn's disease (CD) describe an inappropriate immune response to gut microbiota in genetically susceptible individuals. NOD2 variants are strongly associated with development of CD, and NOD2 is part of the innate immune response to bacteria. This study aimed to identify differences in fecal microbiota in CD patients and non-IBD controls stratified by NOD2 genotype. Methods: Patients with CD and non-IBD controls of known NOD2 genotype were identified from patients in previous UK IBD genetics studies and the Cambridge bioresource (genotyped/phenotyped volunteers)...
February 15, 2018: Inflammatory Bowel Diseases
https://www.readbyqxmd.com/read/29462320/air-quality-inside-police-drug-safes-and-drug-storage-areas
#10
Gregory S Doran, Ralph Deans, Carlo De Filippis, Chris Kostakis, Julia A Howitt
Storage of drug-based evidence inside sealed safes may allow chemical vapors to accumulate, creating concerns of drug exposure by inhalation, or the possibility of cross-contamination of drug evidence. Air samples were taken from inside eight drug safes and one small storage room at nine city and country police stations, as well as a large centralized drug evidence storage vault, in New South Wales (NSW), Australia. Sorbent tubes containing charcoal were used to determine whether any drug residues could be detected in the air, and to identify the types of chemicals present...
February 15, 2018: Journal of Analytical Toxicology
https://www.readbyqxmd.com/read/29460984/a-laboratory-high-throughput-glass-chamber-using-dynamic-headspace-td-gc-ms-method-for-the-analysis-of-whole-brassica-napus-l-plantlet-volatiles-under-cadmium-related-abiotic-stress
#11
Bastien Durenne, Alodie Blondel, Philippe Druart, Marie-Laure Fauconnier
INTRODUCTION: The dynamic headspace sampling technique using thermal desorption, gas chromatography-mass spectrometry (TD-GC/MS) is a powerful method for analysing plant emissions of volatile organic compounds (VOCs), and experiments performed in sterile and controlled conditions can be useful for VOC metabolism investigations. OBJECTIVE: The main purpose of this study was to set up a laboratory high-throughput glass chamber for whole plant volatiles analysis. Brassica napus L...
February 20, 2018: Phytochemical Analysis: PCA
https://www.readbyqxmd.com/read/29459850/bacterial-seed-endophytes-of-domesticated-cucurbits-antagonize-fungal-and-oomycete-pathogens-including-powdery-mildew
#12
Eman M Khalaf, Manish N Raizada
The cucurbit vegetables, including cucumbers, melons and pumpkins, have been cultivated for thousands of years without fungicides. However, their seed germination stage is prone to be infected by soil-borne fungal and oomycete pathogens. Endophytes are symbionts that reside inside plant tissues including seeds. Seed endophytes are founders of the juvenile plant microbiome and can promote host defense at seed germination and later stages. We previously isolated 169 bacterial endophytes associated with seeds of diverse cultivated cucurbits...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29455129/comparative-study-of-volatile-organic-compounds-in-ambient-air-using-observed-mixing-ratios-and-initial-mixing-ratios-taking-chemical-loss-into-account-a-case-study-in-a-typical-urban-area-in-beijing
#13
Jian Gao, Jie Zhang, Hong Li, Lei Li, Linghong Xu, Yujie Zhang, Zhanshan Wang, Xuezhong Wang, Weiqi Zhang, Yizhen Chen, Xi Cheng, Hao Zhang, Liang Peng, Fahe Chai, Yongjie Wei
Volatile organic compounds (VOCs) can react with atmospheric radicals while being transported after being emitted, resulting in substantial losses. Using only observed VOC mixing ratios to assess VOC pollution, is therefore problematic. The observed mixing ratios and initial mixing ratios taking chemical loss into consideration were performed using data for 90 VOCs in the atmosphere in a typical urban area in Beijing in winter 2013 to gain a more accurate view of VOC pollution. The VOC sources, ambient VOC mixing ratios and compositions, variability and influencing factors, contributions to near-ground-ozone and health risks posed were assessed...
February 15, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29455126/removal-mechanisms-of-volatile-organic-compounds-vocs-from-effluent-of-common-effluent-treatment-plant-cetp
#14
Ashwini V Padalkar, Rakesh Kumar
This study investigated the occurrence, removal and influence of plant-operating conditions on removal mechanisms of 83 VOCs in different treatment units of a CETP in Mumbai, treating industrial waste on primary and secondary level. A mass balance approach was used to predict VOC removal by volatilization, stripping, weir drop, adsorption, and biodegradation. Results indicate that ∼17% of VOCs were removed by stripping in equalization tank and ∼8% were removed by weir drop in primary clari-flocculator respectively...
February 1, 2018: Chemosphere
https://www.readbyqxmd.com/read/29454692/from-milk-to-cheese-evolution-of-flavor-fingerprint-of-milk-cream-curd-whey-ricotta-scotta-and-ripened-cheese-obtained-during-summer-alpine-pasture
#15
M Bergamaschi, G Bittante
The role of each step of cheese and ricotta making in development of flavor of cheese and other dairy products is not yet well known. The objectives of this study were to characterize volatile organic compounds (VOC) in cheese and ricotta making with bulk milk from cows grazing in a highland area and to evaluate their evolution in the various dairy products and by-products obtained during the production processes. A group of 148 cows was grazed day and night on pasture from June to September. A total of 7 cheese-making sessions were carried out using the bulk milk collected every 2 wk during summer pasturing according to the artisanal procedure used for Malga cheese production...
February 14, 2018: Journal of Dairy Science
https://www.readbyqxmd.com/read/29454218/atmospheric-pattern-of-volatile-organochlorine-compounds-and-hexachlorobenzene-in-the-surroundings-of-a-chlor-alkali-plant
#16
Barend L van Drooge, Esther Marco, Joan O Grimalt
The outdoor atmospheric distributions of chlorinated volatile organic compounds (VOCs) from locations receiving the emissions of a chlor-alkali plant have been studied. Trichloroethylene and tetrachloroethylene (medians 2.4 μg/m 3 and 1.7 μg/m 3 , respectively) were the most abundant compounds, which was in accordance with the production processes from these installations. The concentrations of trichlorofluoromethane, median 1.6 μg/m 3 , are rather similar to the average levels described in general in the troposphere and cannot be attributed to this specific source...
February 14, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29454209/reconciling-discrepancies-in-the-source-characterization-of-vocs-between-emission-inventories-and-receptor-modeling
#17
Jiamin Ou, Junyu Zheng, Zibing Yuan, Dabo Guan, Zhijiong Huang, Fei Yu, Min Shao, Peter K K Louie
Emission inventory (EI) and receptor model (RM) are two of the three source apportionment (SA) methods recommended by Ministry of Environment of China and used widely to provide independent views on emission source identifications. How to interpret the mixed results they provide, however, were less studied. In this study, a cross-validation study was conducted in one of China's fast-developing and highly populated city cluster- the Pearl River Delta (PRD) region. By utilizing a highly resolved speciated regional EI and a region-wide gridded volatile organic compounds (VOCs) speciation measurement campaign, we elucidated underlying factors for discrepancies between EI and RM and proposed ways for their interpretations with the aim to achieve a scientifically plausible source identification...
February 14, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29451904/phytoforensics-trees-as-bioindicators-of-potential-indoor-exposure-via-vapor-intrusion
#18
Jordan L Wilson, V A Samaranayake, Matt A Limmer, Joel G Burken
Human exposure to volatile organic compounds (VOCs) via vapor intrusion (VI) is an emerging public health concern with notable detrimental impacts on public health. Phytoforensics, plant sampling to semi-quantitatively delineate subsurface contamination, provides a potential non-invasive screening approach to detect VI potential, and plant sampling is effective and also time- and cost-efficient. Existing VI assessment methods are time- and resource-intensive, invasive, and require access into residential and commercial buildings to drill holes through basement slabs to install sampling ports or require substantial equipment to install groundwater or soil vapor sampling outside the home...
2018: PloS One
https://www.readbyqxmd.com/read/29449485/volatile-chemical-products-emerging-as-largest-petrochemical-source-of-urban-organic-emissions
#19
Brian C McDonald, Joost A de Gouw, Jessica B Gilman, Shantanu H Jathar, Ali Akherati, Christopher D Cappa, Jose L Jimenez, Julia Lee-Taylor, Patrick L Hayes, Stuart A McKeen, Yu Yan Cui, Si-Wan Kim, Drew R Gentner, Gabriel Isaacman-VanWertz, Allen H Goldstein, Robert A Harley, Gregory J Frost, James M Roberts, Thomas B Ryerson, Michael Trainer
A gap in emission inventories of urban volatile organic compound (VOC) sources, which contribute to regional ozone and aerosol burdens, has increased as transportation emissions in the United States and Europe have declined rapidly. A detailed mass balance demonstrates that the use of volatile chemical products (VCPs)-including pesticides, coatings, printing inks, adhesives, cleaning agents, and personal care products-now constitutes half of fossil fuel VOC emissions in industrialized cities. The high fraction of VCP emissions is consistent with observed urban outdoor and indoor air measurements...
February 16, 2018: Science
https://www.readbyqxmd.com/read/29448573/sol-gel-deposited-double-layer-tio%C3%A2-and-al%C3%A2-o%C3%A2-anti-reflection-coating-for-silicon-solar-cell
#20
Jinsu Jung, Azmira Jannat, M Shaheer Akhtar, O-Bong Yang
In this work, the deposition of double layer ARC on p-type Si solar cells was carried out by simple spin coating using sol-gel derived Al2O3 and TiO2 precursors for the fabrication of crystalline Si solar cells. The first ARC layer was created by freshly prepared sol-gel derived Al2O3 precursor using spin coating technique and then second ARC layer of TiO2 was deposited with sol-gel derived TiO2 precursor, which was finally annealed at 400 °C. The double layer Al2O3/TiO2 ARC on Si wafer exhibited the low average reflectance of 4...
February 1, 2018: Journal of Nanoscience and Nanotechnology
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