scholarly journals Intestinal Glycoproteins of Germfree Rats. II. Further Studies of the Chemical Composition of Water-soluble Extracts from Intestinal Mucus.

1973 ◽  
Vol 27 ◽  
pp. 2997-3002 ◽  
Author(s):  
Jens K. Wold ◽  
Tore Midtvedt ◽  
Randi Winsnes ◽  
Petri Pajunen ◽  
Jouko Koskikallio ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Water Soluble ◽  
Intestinal Mucus ◽  
Chemical Composition Of Water ◽  
Germfree Rats

scholarly journals Molecular characterization of organic aerosol in the Himalayas: insight from ultra-high-resolution mass spectrometry

2019 ◽  
Vol 19 (2) ◽  
pp. 1115-1128 ◽  
Author(s):  
Yanqing An ◽  
Jianzhong Xu ◽  
Lin Feng ◽  
Xinghua Zhang ◽  
Yanmei Liu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chemical Composition ◽  
High Resolution Mass Spectrometry ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Ion Cyclotron Resonance ◽  
Chemical Composition Of Water ◽  
High Fraction ◽  
Molecular Number

Abstract. An increased trend in aerosol concentration has been observed in the Himalayas in recent years, but the understanding of the chemical composition and sources of aerosol remains poorly understood. In this study, molecular chemical composition of water-soluble organic matter (WSOM) from two filter samples collected during two high aerosol loading periods (denoted as P1 and P2) at a high-altitude station (Qomolangma Station, QOMS; 4276 m a.s.l.) in the northern Himalayas was identified using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR MS). More than 4000 molecular formulas were identified in each filter sample which were classified into two compound groups (CHO and CHON) based on their elemental composition, with both accounting for nearly equal contributions in number (45 %–55 %). The relative abundance weighted mole ratio of O∕Cw for P1 and P2 was 0.43 and 0.39, respectively, and the weighted double bond equivalents (DBEw), an index for the saturation of organic molecules, were 7.12 and 7.87, respectively. Although the O∕Cw mole ratio was comparable for CHO and CHON compounds, the DBEw was significantly higher in CHON compounds than CHO compounds. More than 50 % molecular formulas in the Van Krevelen (VK) diagram (H∕C vs. O∕C) were located in 1–1.5 (H∕C) and 0.2–0.6 (O∕C) regions, suggesting potential lignin-like compounds. The distributions of CHO and CHON compounds in the VK diagram, DBE vs. number of C atoms, and other diagnostic diagrams showed high similarities among each other, suggesting their similar source and/or atmospheric processes. Many formulas formed from biogenic volatile organic compounds (e.g., ozonolysis of α-pinene products) and biomass-burning-emitted compounds (e.g., phenolic compounds) were found in the WSOM, suggesting the important contribution of these two sources in the Himalayas. The high DBE and high fraction of nitrogen-containing aerosol can potentially impact aerosol light absorption in this remote region. Further comprehensive study is needed due to the complexity of organic aerosol and limited molecular number identified in this study.

scholarly journals Molecular characterization of organic aerosol in Himalayas: insight from ultra-high resolution mass spectrometry

2018 ◽  
Author(s):  
Yanqing An ◽  
Jianzhong Xu ◽  
Lin Feng ◽  
Xinhua Zhang ◽  
Yanmei Liu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chemical Composition ◽  
Relative Abundance ◽  
High Resolution Mass Spectrometry ◽  
Water Soluble ◽  
Ion Cyclotron Resonance ◽  
Chemical Composition Of Water ◽  
Molecular Information ◽  
The Common

Abstract. An increasing trend in aerosol concentration has been observed in Himalayas in recent years, but the understanding of the chemical composition and sources of aerosol remains poor. In this study, molecular chemical composition of water soluble organic matter (WSOM) from two filter samples (denoted as F30 and F43) collected during high aerosol loading periods at a high altitude station (Qomolangma Station, QOMS, 4276 m a.s.l.) in the northern Himalayas were identified by positive electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS). More than 4500 molecular formulas were identified in each filter sample which were classified into two compound groups (CHO and CHON) based on their elemental composition with both accounting for nearly equal contributions in number (45 %–55 %). The relative abundance weighted mole ratio of O / Cw for F30 and F43 are 0.43 and 0.38, respectively, and the weighted double bond equivalent (DBEw), an index for the saturation of organic molecules, were 6.26 and 6.92, respectively, suggesting their medium oxidation and saturation degrees. Although the O / Cw mole ratio was comparable for CHO and CHON compounds, the DBEw was significant higher in CHON compounds than CHO compounds. More than 50 % molecular formulas in Van Krevelen (VK) diagram (H / C vs. O / C) located in 1–1.5 (H / C) and 0.2–0.6 (O / C) regions, suggesting potential lignin-like compounds. The distributions of CHO and CHON compounds in VK diagram, DBE vs. number of C atoms, and other diagnose diagrams showed highly similarities between each other suggesting their similar source and/or atmospheric processes. Detailed molecular information in the common formula of these two filters was explored. Many formulas with their homologous series of compounds formed from biogenic volatile organic compounds and biomass mass burning emitted compounds were found in the WSOM with high relative abundance suggesting the important contribution of these two sources in Himalayas. The high DBE and high nitrogen containing of aerosol would have important implication for aerosol light absorption and biogeochemical cycle in this remote region.

scholarly journals Chemical Composition of Water Soluble Inorganic Species in Precipitation at Shihwa Basin, Korea

Atmosphere ◽  
2015 ◽  
Vol 6 (6) ◽  
pp. 732-750 ◽  
Author(s):  
Seung-Myung Park ◽  
Beom-Keun Seo ◽  
Gangwoong Lee ◽  
Sung-Hyun Kahng ◽  
Yu Jang
Keyword(s):  
Chemical Composition ◽  
Water Soluble ◽  
Chemical Composition Of Water ◽  
Inorganic Species

scholarly journals Seasonal variations in PM10 inorganic composition in the Andean city

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rasa Zalakeviciute ◽  
Katiuska Alexandrino ◽  
Yves Rybarczyk ◽  
Alexis Debut ◽  
Karla Vizuete ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Inductively Coupled Plasma ◽  
Chemical Elements ◽  
Large Fraction ◽  
Urban Pollution ◽  
Optical Emission ◽  
High Elevation ◽  
Water Soluble ◽  
Wet Season ◽  
Soluble Ions

Abstract Particulate matter (PM) is one of the key pollutants causing health risks worldwide. While the preoccupation for increased concentrations of these particles mainly depends on their sources and thus chemical composition, some regions are yet not well investigated. In this work the composition of chemical elements of atmospheric PM10 (particles with aerodynamic diameters ≤ 10 µm), collected at the urban and suburban sites in high elevation tropical city, were chemically analysed during the dry and wet seasons of 2017–2018. A large fraction (~ 68%) of PM10 composition in Quito, Ecuador is accounted for by water-soluble ions and 16 elements analysed using UV/VIS spectrophotometer and Inductively Coupled Plasma—Optical Emission Spectroscopy (ICP-OES). Hierarchical clustering analysis was performed to study a correlation between the chemical composition of urban pollution and meteorological parameters. The suburban area displays an increase in PM10 concentrations and natural elemental markers during the dry (increased wind intensity, resuspension of soil dust) season. Meanwhile, densely urbanized area shows increased total PM10 concentrations and anthropogenic elemental markers during the wet season, which may point to the worsened combustion and traffic conditions. This might indicate the prevalence of cardiovascular and respiratory problems in motorized areas of the cities in the developing world.

Chemical composition and in vitro antioxidant evaluation of a water-soluble Moldavian balm (Dracocephalum moldavica L.) extract

LWT ◽  
2007 ◽  
Vol 40 (2) ◽  
pp. 239-248 ◽  
Author(s):  
Keyvan Dastmalchi ◽  
H.J. Damien Dorman ◽  
Müberra Koşar ◽  
Raimo Hiltunen
Keyword(s):  
Chemical Composition ◽  
Water Soluble ◽  
Antioxidant Evaluation

scholarly journals Mixing state and compositional effects on CCN activity and droplet growth kinetics of size-resolved CCN in an urban environment

2012 ◽  
Vol 12 (21) ◽  
pp. 10239-10255 ◽  
Author(s):  
L. T. Padró ◽  
R. H. Moore ◽  
X. Zhang ◽  
N. Rastogi ◽  
R. J. Weber ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Water Soluble ◽  
Anthropogenic Sources ◽  
Droplet Growth ◽  
Mixing State ◽  
Aerosol Composition ◽  
Activation Kinetics ◽  
Aerosol Mixing State ◽  
Kinetics Of ◽  
Ccn Activity

Abstract. Aerosol composition and mixing state near anthropogenic sources can be highly variable and can challenge predictions of cloud condensation nuclei (CCN). The impacts of chemical composition on CCN activation kinetics is also an important, but largely unknown, aspect of cloud droplet formation. Towards this, we present in-situ size-resolved CCN measurements carried out during the 2008 summertime August Mini Intensive Gas and Aerosol Study (AMIGAS) campaign in Atlanta, GA. Aerosol chemical composition was measured by two particle-into-liquid samplers measuring water-soluble inorganic ions and total water-soluble organic carbon. Size-resolved CCN data were collected using the Scanning Mobility CCN Analysis (SMCA) method and were used to obtain characteristic aerosol hygroscopicity distributions, whose breadth reflects the aerosol compositional variability and mixing state. Knowledge of aerosol mixing state is important for accurate predictions of CCN concentrations and that the influence of an externally-mixed, CCN-active aerosol fraction varies with size from 31% for particle diameters less than 40 nm to 93% for accumulation mode aerosol during the day. Assuming size-dependent aerosol mixing state and size-invariant chemical composition decreases the average CCN concentration overprediction (for all but one mixing state and chemical composition scenario considered) from over 190–240% to less than 20%. CCN activity is parameterized using a single hygroscopicity parameter, κ, which averages to 0.16 ± 0.07 for 80 nm particles and exhibits considerable variability (from 0.03 to 0.48) throughout the study period. Particles in the 60–100 nm range exhibited similar hygroscopicity, with a κ range for 60 nm between 0.06–0.076 (mean of 0.18 ± 0.09). Smaller particles (40 nm) had on average greater κ, with a range of 0.20–0.92 (mean of 0.3 ± 0.12). Analysis of the droplet activation kinetics of the aerosol sampled suggests that most of the CCN activate as rapidly as calibration aerosol, suggesting that aerosol composition exhibits a minor (if any) impact on CCN activation kinetics.

Transfer of Abrasive Material at Grinding a Titanium Alloy with a Wheel of Cubic Boron Nitride

2021 ◽  
Vol 316 ◽  
pp. 521-526
Author(s):  
Vladimir A. Nosenko ◽  
Alexander V. Fetisov ◽  
Semen P. Kuznetsov
Keyword(s):  
Titanium Alloy ◽  
Chemical Composition ◽  
Boron Nitride ◽  
Chemical Elements ◽  
Cubic Boron Nitride ◽  
Water Soluble ◽  
Alloy Surface ◽  
Ceramic Bond ◽  
Abrasive Tools ◽  
Wear Products

The article summarizes the results of the of the titanium alloy surface morphology and chemical composition study after grinding with a wheel of cubic boron nitride on a ceramic bond. The titanium alloy was treated using the method of cut-in grinding in the finishing mode using a synthetic water-soluble lubricant-cooling liquid that does not contain mineral oil. The research was carried out using the FEI Versa 3D LoVac electron microscope. Digital photos of the titanium alloy surface at different magnifications are given. Individual objects’ morphology allows us to identify them as wear products of abrasive tools. The chemical composition of the selected objects was studied by local x-ray spectral analysis. CBN crystals are partially or completely pressed into the treated surface and covered with a layer of the treated material. On the surface of CBN crystals, there are chemical elements that are part of the abrasive tool bond.

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