scholarly journals Measurement report: Indirect evidence for the controlling influence of acidity on the speciation of iodine in Atlantic aerosols

2021 ◽  
Vol 21 (17) ◽  
pp. 13067-13076
Author(s):  
Alex R. Baker ◽  
Chan Yodle
Keyword(s):  
Indirect Evidence ◽  
Sea Spray ◽  
Ion Composition ◽  
Dominant Component ◽  
Iodine Compounds ◽  
Iodine Speciation ◽  
Modelling Studies ◽  
Fine Mode ◽  
Acidic Conditions ◽  
High Concentrations

Abstract. The speciation of soluble iodine and major-ion composition were determined in size-fractionated aerosols collected during the AMT21 cruise between Avonmouth, UK, and Punta Arenas, Chile, in September–November 2011. The proportions of iodine species (iodide, iodate and soluble organic iodine (SOI)) varied markedly between size fractions and with the extent to which the samples were influenced by pollutants. In general, fine mode aerosols (< 1 µm) contained higher proportions of both iodide and SOI, while iodate was the dominant component of coarse (< 1 µm) aerosols. The highest proportions of iodate were observed in aerosols that contained (alkaline) unpolluted sea spray or mineral dust. Fine mode samples with high concentrations of acidic species (e.g. non-sea-salt sulfate) contained very little iodate and elevated proportions of iodide and SOI. These results are in agreement with modelling studies that indicate that iodate can be reduced under acidic conditions and that the resulting hypoiodous acid (HOI) can react with organic matter to produce SOI and iodide. Further work that investigates the link between iodine speciation and aerosol pH directly, as well as studies on the formation and decay of organo-iodine compounds under aerosol conditions, will be necessary before the importance of this chemistry in regulating aerosol iodine speciation can be confirmed.

scholarly journals Measurement report: Indirect evidence for the controlling influence of acidity on the speciation of iodine in Atlantic aerosols

2021 ◽  
Author(s):  
Alex R. Baker ◽  
Chan Yodle
Keyword(s):  
Indirect Evidence ◽  
Ion Composition ◽  
Iodine Species ◽  
Dominant Component ◽  
Iodine Compounds ◽  
Iodine Speciation ◽  
Modelling Studies ◽  
Fine Mode ◽  
Acidic Conditions ◽  
High Concentrations

Abstract. The speciation of iodine and major ion composition were determined in size-fractionated aerosols collected during the AMT21 cruise between Avonmouth, UK and Punta Arenas, Chile in September–November 2011. The proportions of iodine species (iodide, iodate and soluble organic iodine (SOI)) varied markedly between size fractions and with the extent to which the samples were influenced by pollutants. In general, fine mode aerosols (< 1 µm) contained higher proportions of both iodide and SOI, while iodate was the dominant component of coarse (< 1 µm) aerosols. The highest proportions of iodate were observed in aerosols that contained (alkaline) unpolluted seaspray or mineral dust. Fine mode samples with high concentrations of acidic species (e.g. non-seasalt sulfate) contained very little iodate and elevated proportions of iodide and SOI. These results are in agreement with modelling studies that indicate that iodate can be reduced under acidic conditions and that the resulting hypoiodous acid (HOI) can react with organic matter to produce SOI and iodide. Further work that investigates the link between iodine speciation and aerosol pH directly, as well as studies on the formation and decay of organo-iodine compounds under aerosol conditions, will be necessary before the importance of this chemistry in regulating aerosol iodine speciation can be confirmed.

scholarly journals Iodine speciation and size distribution in ambient aerosols at a coastal new particle formation hotspot in China

2019 ◽  
Vol 19 (6) ◽  
pp. 4025-4039 ◽  
Author(s):  
Huan Yu ◽  
Lili Ren ◽  
Xiangpeng Huang ◽  
Mingjie Xie ◽  
Jun He ◽  
...  
Keyword(s):  
Particle Formation ◽  
Coastal Areas ◽  
Aerosol Sample ◽  
Size Distributions ◽  
New Particle Formation ◽  
Nucleation Mode ◽  
Iodine Species ◽  
Organic Iodine ◽  
Iodine Compounds ◽  
Iodine Speciation

Abstract. Intense new particle formation (NPF) events were observed in the coastal atmosphere during algae growth and farming season at Xiangshan gulf of the east China coast. High nucleation-mode iodine concentrations measured by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) confirmed that the NPF events were induced by iodine species. Our study provides important information on iodine speciation, size distributions, and its role in NPF in the context of heavy air pollution in China's coastal areas. For the first time, we identified 5 inorganic iodine species, 45 organic iodine compounds (35 molecular formulas), and a group of iodide–organic adducts in aerosols. The concentrations and size distributions of iodine species down to 10 nm were measured during the iodine-induced NPF, continental NPF, and non-NPF days at the coastal site and compared to those at an inland site. The iodine in the above four aerosol sample types were characterized by iodate, aromatic iodine compounds, iodoacetic acid or iodopropenoic acid, and iodide–organic adducts, respectively. Iodide and organic iodine compounds were found in the nucleation-mode particles; however, it is still not clear whether they contributed to nucleation or just new particle growth. Wild algae, as well as farmed algae, could be an important NPF source in China's coastal areas.

scholarly journals Amphiphilic Block Copolymers Bearing Hydrophobic γ-Tocopherol Groups with Labile Acetal Bond

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 36
Author(s):  
Shotaro Yukioka ◽  
Takuya Kitadume ◽  
Suchismita Chatterjee ◽  
Gan Ning ◽  
Tooru Ooya ◽  
...  
Keyword(s):  
Diblock Copolymer ◽  
Main Chain ◽  
Polymer Micelles ◽  
Poly Ethylene Glycol ◽  
The Core ◽  
Anticancer Effects ◽  
Acidic Conditions ◽  
High Concentrations ◽  
Poly Ethylene ◽  
Hydrophobic Cores

High concentrations of γ-tocopherol (γTCP) tend to show antioxidant, anti-inflammatory, and anticancer effects. In this study, we prepared polymer micelles under acidic conditions with a controlled release of γTCP due to the decomposition of pendant acetal bonds. First, a precursor diblock copolymer composed of poly(ethylene glycol) (PEG) and acrylic acid (AA) was prepared. This was followed by the synthesis of an amphiphilic diblock copolymer (PEG54-P(AA/VE6/γTCP29)140), incorporated into hydrophobic γTCP pendant groups attached to the main chain through an acetal bond. The prepared PEG54-P(AA/VE6/γTCP29)140 was further dispersed in water to form polymer micelles composed of hydrophobic cores that were generated from a hydrophobic block containing γTCPs and hydrophilic shells on the surface. Under acidic conditions, γTCP was then released from the core of the polymer micelles due to the decomposition of the pendant acetal bonds. In addition, polymer micelles swelled under acidic conditions due to hydration of the core.

scholarly journals Investigating size-segregated sources of elemental composition of particulate matter in the South China Sea during the 2011 Vasco Cruise

2019 ◽  
Author(s):  
Miguel Ricardo A. Hilario ◽  
Melliza T. Cruz ◽  
Maria Obiminda L. Cambaliza ◽  
Jeffrey S. Reid ◽  
Peng Xian ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Linear Regression ◽  
South China Sea ◽  
Biomass Burning ◽  
South China ◽  
The South China Sea ◽  
Sea Spray ◽  
Soil Dust ◽  
Back Trajectories ◽  
Fine Mode

Abstract. The South China Sea/West Philippine Sea (SCS/WPS) is a receptor of various natural and anthropogenic aerosol species from throughout greater Asia. In combination with its archipelagic/peninsular terrain and strong Asian monsoon climate, the SCS/WPS hosts one of the most complex aerosol-meteorological systems in the world. However, aside from the well-known biomass burning emissions from Indonesia and Borneo, the current understanding of aerosol sources is limited-especially in remote marine environments. In September 2011, a 2-week research cruise was conducted near Palawan, Philippines to sample the remote SCS/WPS environment. Size-segregated aerosol data was collected using a Davis Rotating-drum Unit size-cut Monitor sampler and analyzed for concentrations of 28 selected elements. Positive Matrix Factorization (PMF) was performed separately on the coarse, fine, and ultrafine size ranges to determine possible sources and their contributions to the total particulate matter mass. Additionally, size distribution plots, time series plots, back trajectories and satellite data were used in interpreting factors. Using tracers of various sources, a linear regression analysis and correlation matrices showed the presence of soil dust and sea spray in the coarse mode, biomass burning in the fine mode and oil combustion in the ultrafine mode. Mass distributions showed elevated aerosol concentrations towards the end of the sampling period which coincided with a shift of air mass back trajectories to Southern Kalimantan. Covariance between coarse and fine mode sources were observed. The PMF analysis resolved five sources across the three size ranges: biomass burning, oil combustion, soil dust, sea spray and a fly ash factor largely composed of heavy metals. The agreement between the PMF and the linear regression analyses suggests the robustness of the PMF solution. While biomass burning is indeed a key source of aerosol, the study shows the presence of other important sources in the SCS/WPS. Understanding these sources is key to characterizing the chemical profile of the SCS/WPS and, by extension, developing our understanding of aerosol-cloud behavior in the region.

scholarly journals Inherited dysfunctional platelet P2Y12 receptor mutations associated with bleeding disorders

2016 ◽  
Vol 36 (04) ◽  
pp. 279-283 ◽  
Author(s):  
Anna Lecchi ◽  
Eti Femia ◽  
Silvia Paoletta ◽  
Arnaud Dupuis ◽  
Philippe Ohlmann ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Structural Integrity ◽  
Present Report ◽  
Critical Role ◽  
Receptor Expression ◽  
Severe Bleeding ◽  
Modelling Studies ◽  
Agonist And Antagonist ◽  
High Concentrations

SummaryThe platelet adenosine 5’-diphosphate (ADP) receptor P2Y12 (P2Y12R) plays a critical role in platelet aggregation. The present report illustrates an update of dysfunctional platelet P2Y12R mutations diagnosed with congenital lifelong bleeding problems. Described patients with heterozygous or homozygous substitution in the P2Y12R gene and qualitative abnormalities of the platelet P2Y12R are summarized. Recently, a further dysfunctional variant of P2Y12R has been identified in two brothers who presented with a lifelong severe bleeding disorder. During in vitro aggregation studies, the patient´s platelets show a markedly reduced and rapid reversible ADP-promoted aggregation. A homozygous c.561T>A substitution that changes the codon for His187 to Gln (p.His187Gln) in the P2Y12R gene has been identified. This mutation causes no change in receptor expression but decreases the affinity of the ligand for the receptor, even at high concentrations. Structure modelling studies indicated that the p.His187Gln mutation, located in the fifth transmembrane spanning domain (TM5), impairs conformational changes of the receptor. Structural integrity of the TM5 region is necessary for agonist and antagonist binding and for correct receptor function.

scholarly journals A New Fungal Isolate, Penidiella sp. Strain T9, Accumulates the Rare Earth Element Dysprosium

2015 ◽  
Vol 81 (9) ◽  
pp. 3062-3068 ◽  
Author(s):  
Takumi Horiike ◽  
Mitsuo Yamashita
Keyword(s):  
Rare Earth ◽  
Mine Drainage ◽  
Liquid Waste ◽  
Morphological Characterization ◽  
Rrna Gene ◽  
Content Type ◽  
Cell Pellet ◽  
Acidic Conditions ◽  
High Concentrations ◽  
Rrna Gene Sequencing

ABSTRACTWith an aim to develop a highly efficient method for the recovery of rare earth elements (REEs) by using microorganisms, we attempted to isolate dysprosium (Dy)-accumulating microorganisms that grow under acidic conditions from environmental samples containing high concentrations of heavy metals. One acidophilic strain, T9, which was isolated from an abandoned mine, decreased the concentration of Dy in medium that contained 100 mg/liter Dy to 53 mg/liter Dy after 3 days of cultivation at pH 2.5. The Dy content in the cell pellet of the T9 strain was 910 μg/mg of dry cells. The T9 strain also accumulated other REEs. Based on the results of 28S-D1/D2 rRNA gene sequencing and morphological characterization, we designated this fungal strainPenidiellasp. T9. Bioaccumulation of Dy was observed on the cell surface of the T9 strain by elemental mapping using scanning electron microscopy-energy dispersive X-ray spectroscopy. Our results indicate thatPenidiellasp. T9 has the potential to recover REEs such as Dy from mine drainage and industrial liquid waste under acidic conditions.

scholarly journals A theoretical interpretation of ion composition measured on board the 'Active' satellite in the European sector during April 10−12, 1990 geomagnetic storm

1995 ◽  
Vol 13 (6) ◽  
pp. 608-616 ◽  
Author(s):  
M. Förster ◽  
V. Mikhailov ◽  
A. Mikhailov ◽  
J. Smilauer
Keyword(s):  
Geomagnetic Storm ◽  
Theoretical Calculations ◽  
Recovery Phase ◽  
Molecular Ions ◽  
Ion Concentration ◽  
Theoretical Interpretation ◽  
Ion Composition ◽  
Light Ions ◽  
High Concentrations ◽  
European Sector

Abstract. Ion composition measurements on board the ACTIVE satellite during the recovery phase of a strong geomagnetic storm of 10-12 April 1990 revealed extremely high concentrations (up to 103 cm-3) of the NO+, O+2, N+2 molecular ions in the topside F2-region of the European high-latitude zone. Concentrations of O+, N+, He+, H+ light ions were slightly decreased relative to prestorm quite conditions. Theoretical calculations were used to analyze the observed variations in ion concentration. Increased neutral temperature and [O2], [N2] are shown to be the main reasons for the observed ion concentration variations.

scholarly journals Marine productivity and synoptic meteorology drive summer-time variability in Southern Ocean aerosols

2020 ◽  
Vol 20 (13) ◽  
pp. 8047-8062
Author(s):  
Joel Alroe ◽  
Luke T. Cravigan ◽  
Branka Miljevic ◽  
Graham R. Johnson ◽  
Paul Selleck ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Cloud Condensation Nuclei ◽  
Large Diameter ◽  
Convective Transport ◽  
Sea Spray ◽  
Strong Wind ◽  
Condensation Nuclei ◽  
Air Mass ◽  
Air Masses ◽  
High Concentrations

Abstract. Cloud–radiation interactions over the Southern Ocean are not well constrained in climate models, in part due to uncertainties in the sources, concentrations, and cloud-forming potential of aerosol in this region. To date, most studies in this region have reported measurements from fixed terrestrial stations or a limited set of instrumentation and often present findings as broad seasonal or latitudinal trends. Here, we present an extensive set of aerosol and meteorological observations obtained during an austral summer cruise across the full width of the Southern Ocean south of Australia. Three episodes of continental-influenced air masses were identified, including an apparent transition between the Ferrel atmospheric cell and the polar cell at approximately 64∘ S, and accompanied by the highest median cloud condensation nuclei (CCN) concentrations, at 252 cm−3. During the other two episodes, synoptic-scale weather patterns diverted air masses across distances greater than 1000 km from the Australian and Antarctic coastlines, respectively, indicating that a large proportion of the Southern Ocean may be periodically influenced by continental air masses. In all three cases, a highly cloud-active accumulation mode dominated the size distribution, with up to 93 % of the total number concentration activating as CCN. Frequent cyclonic weather conditions were observed at high latitudes and the associated strong wind speeds led to predictions of high concentrations of sea spray aerosol. However, these modelled concentrations were not achieved due to increased aerosol scavenging rates from precipitation and convective transport into the free troposphere, which decoupled the air mass from the sea spray flux at the ocean surface. CCN concentrations were more strongly impacted by high concentrations of large-diameter Aitken mode aerosol in air masses which passed over regions of elevated marine biological productivity, potentially contributing up to 56 % of the cloud condensation nuclei concentration. Weather systems were vital for aerosol growth in biologically influenced air masses and in their absence ultrafine aerosol diameters were less than 30 nm. These results demonstrate that air mass meteorological history must be considered when modelling sea spray concentrations and highlight the potential importance of sub-grid-scale variability when modelling atmospheric conditions in the remote Southern Ocean.

scholarly journals Odstraňování rtuti z kyselých roztoků chloridu rtuťnatého sorbenty připravenými katalyzovanou vulkanizací rostlinných olejů

2022 ◽  
Vol 116 (1) ◽  
pp. 48-55
Author(s):  
Karel Svoboda ◽  
Tomáš Ružovič ◽  
Michael Pohořelý ◽  
Miloslav Hartman ◽  
Michal Šyc
Keyword(s):  
Flue Gas ◽  
Hot Water ◽  
Metallic Elements ◽  
Mercury Ions ◽  
Metallic Mercury ◽  
Acidic Solutions ◽  
Mercury Compounds ◽  
Acidic Conditions ◽  
High Concentrations ◽  
Neutral Conditions

Mercury is a metallic element, dangerous and toxic for the environment. Presently, the incineration of municipal solid waste (MSW) belongs to important sources of Hg emissions. Methods of conversion of metallic mercury and mercury compounds from soluble and toxic forms into water insoluble/non-toxic form (HgS) are sought after. Gaseous HCl and a significant part of HgCl2 vapors present in flue gas from incineration of MSW can be removed there by absorption in hot water. Efficiencies of Hg2+ removal from acidic water solutions by means of sorbents prepared by catalyzed reaction of sulfur with vegetable oils (inverse vulcanization) were studied. These kinds of sorbents were tested and found to be exploitable for selective removal of mercury ions from aqueous solutions, particularly from acidic solutions containing HCl at higher temperatures (50–75 °C). Presence of relatively high concentrations of salts of some other metallic elements (Fe, Zn, Ca) had only very small effects on Hg-sorption. Mercury adsorbed on such sorbents converts relatively quickly into a non-toxic form (HgS). Reactive sulfides and SH‑groups present on the surface of the sorbent particles contribute to a faster sorption of mercury and its conversion to HgS. Leaching of zinc from the catalyst (Zn‑diethyldithiocarbamate) present in the vulcanized sorbents is negligible at neutral conditions and small (about 10 %) at acidic conditions (pH = 1.5).

Variations in FLT3 ligand levels during the course of AML treatment.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 7026-7026 ◽  
Author(s):  
Michael Richard Grunwald ◽  
Mark J. Levis
Keyword(s):  
Kinase Inhibitors ◽  
Indirect Evidence ◽  
Flt3 Ligand ◽  
Consolidation Chemotherapy ◽  
Stromal Microenvironment ◽  
Transient Rise ◽  
High Concentrations ◽  
One Year ◽  
The Relationship

7026 Background: FLT3 ligand (FL) is a hematopoietic growth factor expressed in many tissues. AML patients who are administered myeloablative therapy exhibit a marked and transient rise in plasma FL concentrations. Furthermore, the presence of high concentrations (1000 pg/mL) of FL impedes the efficacy of FLT3 tyrosine kinase inhibitors in vitro. However, the behavior of FL concentrations throughout the course of AML treatment remains unknown. This pilot study was undertaken to track the relationship between AML therapy and FL levels over time. Methods: Ten AML patients were enrolled in an IRB-approved procurement protocol. Blood samples were collected at weekly intervals for one year, and plasma was isolated by centrifugation. Plasma FL and stem cell factor (SCF) concentrations were measured by ELISA. Results: We observed four distinct patterns in FL fluctuations. First, in all cases where induction or consolidation chemotherapy resulted in an aplastic bone marrow (nine patients), FL concentrations rose markedly and consistently to levels >1000 pg/mL following the administration of chemotherapy. Second, in three of four patients whose leukemia was refractory to induction chemotherapy, FL concentrations remained below 500 pg/mL during induction. Third, in two patients receiving the FLT3 TKI sorafenib, FL concentrations did not rise above 500 pg/mL while on this medication. Fourth, in one patient receiving the hypomethylating agent 5-azacitidine, FL concentrations remained below 100 pg/mL throughout the course of therapy. SCF concentrations did not vary throughout the course of chemotherapy. Conclusions: An “FL surge” was seen when cytotoxic chemotherapy resulted in aplasia. This FL surge was not seen with sorafenib or 5-azacitidine. In addition, the FL surge was attenuated in three patients whose leukemia was refractory to chemotherapy. These observations give rise to two new hypotheses regarding FL: 1) It is possible to maintain lower FL levels with targeted agents than with chemotherapy; and 2) Residual leukemia appears to inhibit the FL surge, providing indirect evidence of cross-talk between leukemia and the stromal microenvironment. This inhibition may be the explanation for why AML patients develop pancytopenia early in relapse.

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