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Gen M, Zheng H, Sun Y, Xu W, Ma N, Su H, Cheng Y, Wang S, Xing J, Zhang S, Xue L, Xue C, Mu Y, Tian X, Matsuki A, Song S. Rapid hydrolysis of NO 2 at High Ionic Strengths of Deliquesced Aerosol Particles. Environ Sci Technol 2024; 58:7904-7915. [PMID: 38661303 DOI: 10.1021/acs.est.3c08810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Nitrogen dioxide (NO2) hydrolysis in deliquesced aerosol particles forms nitrous acid and nitrate and thus impacts air quality, climate, and the nitrogen cycle. Traditionally, it is considered to proceed far too slowly in the atmosphere. However, the significance of this process is highly uncertain because kinetic studies have only been made in dilute aqueous solutions but not under high ionic strength conditions of the aerosol particles. Here, we use laboratory experiments, air quality models, and field measurements to examine the effect of the ionic strength on the reaction kinetics of NO2 hydrolysis. We find that high ionic strengths (I) enhance the reaction rate constants (kI) by more than an order of magnitude compared to that at infinite dilution (kI=0), yielding log10(kI/kI=0) = 0.04I or rate enhancement factor = 100.04I. A state-of-the-art air quality model shows that the enhanced NO2 hydrolysis reduces the negative bias in the simulated concentrations of nitrous acid by 28% on average when compared to field observations over the North China Plain. Rapid NO2 hydrolysis also enhances the levels of nitrous acid in other polluted regions such as North India and further promotes atmospheric oxidation capacity. This study highlights the need to evaluate various reaction kinetics of atmospheric aerosols with high ionic strengths.
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Affiliation(s)
- Masao Gen
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Haotian Zheng
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
- CMA-NKU Cooperative Laboratory for Atmospheric Environment Health Research, Tianjin 300350, China
| | - Yele Sun
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Wanyun Xu
- State Key Laboratory of Severe Weather, Key Laboratory for Atmospheric Chemistry, Institute of Atmospheric Composition and Environmental Meteorology, Chinese Academy of Meteorological Sciences, Beijing 100081, China
| | - Nan Ma
- Institute for Environmental and Climate Research (ECI), Jinan University, Guangzhou 511443, China
| | - Hang Su
- Max Planck Institute for Chemistry, Mainz 55128, Germany
| | - Yafang Cheng
- Max Planck Institute for Chemistry, Mainz 55128, Germany
| | - Shuxiao Wang
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Jia Xing
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Shuping Zhang
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Likun Xue
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Chaoyang Xue
- Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), CNRS - Université Orléans - CNES, Orléans Cedex 2 45071, France
| | - Yujing Mu
- Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xiao Tian
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Tianjin Key Laboratory of Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Atsushi Matsuki
- Institute of Nature and Environmental Technology, Kanazawa University, Kanazawa 920-1192, Japan
| | - Shaojie Song
- CMA-NKU Cooperative Laboratory for Atmospheric Environment Health Research, Tianjin 300350, China
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Tianjin Key Laboratory of Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
- Harvard-China on Energy, Economy, and Environment, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
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Abstract
The surface tension of aerosol particles can potentially affect cloud droplet activation. Hence, direct measurement of the surface tensions of deliquesced aerosol particles is essential but is challenging. Here, we report in situ surface tension measurements based on a novel method that couples a linear quadrupole electrodynamic balance (EDB) with quasi-elastic light scattering (QELS). The EDB-QELS is validated using surface tension measurements of atmospherically relevant inorganic and organic droplets. The surface tension results reasonably agree with the reference values in the range of ∼50-90 mN m-1. We find a significant size dependence for sodium chloride droplets containing surface-active species (sodium dodecyl sulfate) in the size range of ∼5-18 μm. The surface tension increases from ∼55 to 80 mN m-1 with decreased size. Relative humidity (RH)-dependent surface tensions of mixed ammonium sulfate (AS) and polyethylene glycol droplets reveal the onset of liquid-liquid phase separation. Droplets containing water-soluble matter extracted from ambient aerosol samples and 2.3-2.9 M AS exhibit a ∼30% reduction in surface tension in the presence of ∼50 mmol-C L-1 water-soluble organic carbon, compared to pure water (∼72 mN m-1). The approach can offer size-resolved and RH-dependent surface tension measurements of deliquesced aerosol particles.
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Affiliation(s)
- Masao Gen
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Akihide Hibara
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1-W4-19 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Phuong Nguyet Phung
- Graduate School of Environmental Studies, Nagoya University, Nagoya 464-8601, Japan
| | - Yuzo Miyazaki
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Michihiro Mochida
- Graduate School of Environmental Studies, Nagoya University, Nagoya 464-8601, Japan
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya 464-8601, Japan
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Fukuyama M, Nishinami S, Maruyama Y, Ozawa T, Tomita S, Ohhashi Y, Kasuya M, Gen M, Chatani E, Shiraki K, Hibara A. Detection of Fibril Nucleation in Micrometer-Sized Protein Condensates and Suppression of Sup35NM Fibril Nucleation by Liquid-Liquid Phase Separation. Anal Chem 2023. [PMID: 37347214 DOI: 10.1021/acs.analchem.3c00766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/23/2023]
Abstract
Elucidating the link between amyloid fibril formation and liquid-liquid phase separation (LLPS) is crucial in understanding the pathologies of various intractable human diseases. However, the effect of condensed protein droplets generated by LLPS on nucleation (the initial step of amyloid formation) remains unclear because of the lack of available quantitative analysis techniques. This study aimed to develop a measurement method for the amyloid droplet nucleation rate based on image analysis. We developed a method to fix micrometer-sized droplets in gel for long-term observation of protein droplets with known droplet volumes. By combining this method with image analysis, we determined the nucleation dynamics in droplets of a prion disease model protein, Sup35NM, at the single-event level. We found that the nucleation was unexpectedly suppressed by LLPS above the critical concentration (C*) and enhanced below C*. We also revealed that the lag time in the Thioflavin T assay, a semi-quantitative parameter of amyloid nucleation rate, does not necessarily reflect nucleation tendencies in droplets. Our results suggest that LLPS can suppress amyloid nucleation, contrary to the conventional hypothesis that LLPS enhances it. We believe that the proposed quantitative analytical method will provide insights into the role of LLPS from a pathological perspective.
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Affiliation(s)
- Mao Fukuyama
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Sendai, Miyagi 980-8577, Japan
- Organization for Advanced Studies, Tohoku University, 2-1-1 Katahira, Sendai, Miyagi 980-8577, Japan
| | - Suguru Nishinami
- Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennoudai, Tsukuba, Ibaraki 305-8573, Japan
| | - Yoko Maruyama
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Sendai, Miyagi 980-8577, Japan
| | - Taiki Ozawa
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Sendai, Miyagi 980-8577, Japan
| | - Shunsuke Tomita
- Health and Medical Research Institute, The National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Yumiko Ohhashi
- Graduate School of Science, Kobe University, 1-1, Rokkoudaichou, Nada, Kobe, Hyogo 657-8501, Japan
| | - Motohiro Kasuya
- Faculty of Production Systems Engineering and Sciences, Komatsu University, Nu 1-3, Yonchoumemachi, Komatsu, Ishikawa 923-0971, Japan
| | - Masao Gen
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Sendai, Miyagi 980-8577, Japan
| | - Eri Chatani
- Graduate School of Science, Kobe University, 1-1, Rokkoudaichou, Nada, Kobe, Hyogo 657-8501, Japan
| | - Kentaro Shiraki
- Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennoudai, Tsukuba, Ibaraki 305-8573, Japan
| | - Akihide Hibara
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Sendai, Miyagi 980-8577, Japan
- Riken, 2-1, Hirosawa, Wako, Saitama 351-0198, Japan
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Zvyagin SA, Ponomaryov AN, Wosnitza J, Hirai D, Hiroi Z, Gen M, Kohama Y, Matsuo A, Matsuda YH, Kindo K. Dimensional reduction and incommensurate dynamic correlations in the [Formula: see text] triangular-lattice antiferromagnet Ca 3ReO 5Cl 2. Nat Commun 2022; 13:6310. [PMID: 36274086 PMCID: PMC9588769 DOI: 10.1038/s41467-022-33992-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 10/07/2022] [Indexed: 12/03/2022] Open
Abstract
The observation of spinon excitations in the [Formula: see text] triangular antiferromagnet Ca3ReO5Cl2 reveals a quasi-one-dimensional (1D) nature of magnetic correlations, in spite of the nominally 2D magnetic structure. This phenomenon is known as frustration-induced dimensional reduction. Here, we present high-field electron spin resonance spectroscopy and magnetization studies of Ca3ReO5Cl2, allowing us not only to refine spin-Hamiltonian parameters, but also to investigate peculiarities of its low-energy spin dynamics. We argue that the presence of the uniform Dzyaloshinskii-Moriya interaction (DMI) shifts the spinon continuum in momentum space and, as a result, opens a zero-field gap at the Γ point. We observed this gap directly. The shift is found to be consistent with the structural modulation in the ordered state, suggesting this material as a perfect model triangular-lattice system, where a pure DMI-spiral ground state can be realized.
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Affiliation(s)
- S. A. Zvyagin
- Dresden High Magnetic Field Laboratory (HLD-EMFL) and Würzburg-Dresden Cluster of Excellence ct.qmat, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - A. N. Ponomaryov
- Dresden High Magnetic Field Laboratory (HLD-EMFL) and Würzburg-Dresden Cluster of Excellence ct.qmat, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
- Present Address: Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - J. Wosnitza
- Dresden High Magnetic Field Laboratory (HLD-EMFL) and Würzburg-Dresden Cluster of Excellence ct.qmat, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
- Institut für Festkörper- und Materialphysik, TU Dresden, 01062 Dresden, Germany
| | - D. Hirai
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 Japan
| | - Z. Hiroi
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 Japan
| | - M. Gen
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 Japan
| | - Y. Kohama
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 Japan
| | - A. Matsuo
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 Japan
| | - Y. H. Matsuda
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 Japan
| | - K. Kindo
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 Japan
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Abstract
We report a spray-drying method to fabricate silver nanoparticle (AgNP) aggregates for application in surface-enhanced Raman spectroscopy (SERS). A custom-built system was used to fabricate AgNP aggregates of four sizes, 48, 86, 151, and 218 nm, from drying droplets containing AgNPs atomized from an AgNP suspension. Sample solutions of Rhodamine B (RhB) at 10-6, 10-8, and 10-10 M concentrations were dropped onto the AgNP aggregates as probe molecules to examine the enhancement of the Raman signals of the RhB. The ordering of the analytical enhancement factors (AEFs) by aggregate size at a 10-6 M RhB was 86 nm > 218 nm > 151 nm > 48 nm. When RhB concentrations are below 10-8 M, the 86 and 151 nm AgNP aggregates show clear RhB peaks. The AEFs of the 86 nm AgNP aggregates were the highest in all four aggregates and higher than those of the 218-nm aggregates, although the 218-nm aggregates had more hot spots where Raman enhancement occurred. This finding was attributable to the deformation and damping of the electron cloud in the highly aggregated AgNPs, reducing the sensitivity for Raman enhancement. When RhB was premixed with the AgNP suspension prior to atomization, the AEFs at 10-8 M RhB rose ~ 100-fold compared to those in the earlier experiments (the post-dropping route). This significant enhancement was probably caused by the increased opportunity for the trapping of the probe molecules in the hot spots.
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Affiliation(s)
- Chigusa Matsumoto
- Graduate School of Science and Technology, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Masao Gen
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kanazawa, 920-1192, Japan.
| | - Atsushi Matsuki
- Institute of Nature and Environmental Technology, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Takafumi Seto
- Graduate School of Science and Technology, Kanazawa University, Kanazawa, 920-1192, Japan.
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Zhang R, Gen M, Liang Z, Li YJ, Chan CK. Photochemical Reactions of Glyoxal during Particulate Ammonium Nitrate Photolysis: Brown Carbon Formation, Enhanced Glyoxal Decay, and Organic Phase Formation. Environ Sci Technol 2022; 56:1605-1614. [PMID: 35023733 DOI: 10.1021/acs.est.1c07211] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Glyoxal is an important precursor of aqueous secondary organic aerosol (aqSOA). Its photooxidation to form organic acids and oligomers and reactions with reduced nitrogen compounds to form brown carbon (BrC) have been extensively investigated separately, although these two types of reactions can occur simultaneously during the daytime. Here, we examine the reactions of glyoxal during photooxidation and BrC formation in premixed NH4NO3 + Glyoxal droplets. We find that nitrate photolysis and photosensitization can enhance the decay rates of glyoxal by a factor of ∼5 and ∼6 compared to those under dark, respectively. A significantly enhanced glyoxal decay rate by a factor of ∼12 was observed in the presence of both nitrate photolysis and photosensitization. Furthermore, a new organic phase was formed in irradiated NH4NO3 + Glyoxal droplets, which had no noticeable degradation under prolonged photooxidation. It was attributed to the imidazole oxidation mediated by nitrate photolysis and/or photosensitization. The persistent organic phase suggests the potential to contribute to SOA formation in ambient fine particles. This study highlights that glyoxal photooxidation mediated by nitrate photolysis and photosensitization can significantly enhance the atmospheric sink of glyoxal, which may partially narrow the gap between model predictions and field measurements of ambient glyoxal concentrations.
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Affiliation(s)
- Ruifeng Zhang
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
| | - Masao Gen
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Zhancong Liang
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
| | - Yong Jie Li
- Department of Civil and Environmental Engineering, and Centre for Regional Oceans, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - Chak Keung Chan
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
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Wang Y, Huang DD, Huang W, Liu B, Chen Q, Huang R, Gen M, Mabato BRG, Chan CK, Li X, Hao T, Tan Y, Hoi KI, Mok KM, Li YJ. Enhanced Nitrite Production from the Aqueous Photolysis of Nitrate in the Presence of Vanillic Acid and Implications for the Roles of Light-Absorbing Organics. Environ Sci Technol 2021; 55:15694-15704. [PMID: 34784716 DOI: 10.1021/acs.est.1c04642] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A prominent source of hydroxyl radicals (•OH), nitrous acid (HONO) plays a key role in tropospheric chemistry. Apart from direct emission, HONO (or its conjugate base nitrite, NO2-) can be formed secondarily in the atmosphere. Yet, how secondary HONO forms requires elucidation, especially for heterogeneous processes involving numerous organic compounds in atmospheric aerosols. We investigated nitrite production from aqueous photolysis of nitrate for a range of conditions (pH, organic compound, nitrate concentration, and cation). Upon adding small oxygenates such as ethanol, n-butanol, or formate as •OH scavengers, the average intrinsic quantum yield of nitrite [Φ(NO2-)] was 0.75 ± 0.15%. With near-UV-light-absorbing vanillic acid (VA), however, the effective Φ(NO2-) was strongly pH-dependent, reaching 8.0 ± 2.1% at a pH of 8 and 1.5 ± 0.39% at a more atmospherically relevant pH of 5. Our results suggest that brown carbon (BrC) may greatly enhance the nitrite production from the aqueous nitrate photolysis through photosensitizing reactions, where the triplet excited state of BrC may generate solvated electrons, which reduce nitrate to NO2 for further conversion to nitrite. This photosensitization process by BrC chromophores during nitrate photolysis under mildly acidic conditions may partly explain the missing HONO in urban environments.
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Affiliation(s)
- Yalin Wang
- Department of Civil and Environmental Engineering, and Centre for Regional Oceans, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - Dan Dan Huang
- Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Wanyi Huang
- Department of Civil and Environmental Engineering, and Centre for Regional Oceans, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - Ben Liu
- Department of Civil and Environmental Engineering, and Centre for Regional Oceans, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - Qi Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, BIC-ESAT and IJRC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Rujin Huang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Masao Gen
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | | | - Chak K Chan
- School of Energy and Environment, City University of Hong Kong, Hong Kong 999077, China
| | - Xue Li
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou 510632, China
| | - Tianwei Hao
- Department of Civil and Environmental Engineering, and Centre for Regional Oceans, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - Yunkai Tan
- Department of Civil and Environmental Engineering, and Centre for Regional Oceans, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - Ka In Hoi
- Department of Civil and Environmental Engineering, and Centre for Regional Oceans, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - Kai Meng Mok
- Department of Civil and Environmental Engineering, and Centre for Regional Oceans, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - Yong Jie Li
- Department of Civil and Environmental Engineering, and Centre for Regional Oceans, Faculty of Science and Technology, University of Macau, Macau 999078, China
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Gen M, Zhang R, Chan CK. Nitrite/Nitrous Acid Generation from the Reaction of Nitrate and Fe(II) Promoted by Photolysis of Iron-Organic Complexes. Environ Sci Technol 2021; 55:15715-15723. [PMID: 34812628 DOI: 10.1021/acs.est.1c05641] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Gaseous nitrous acid (HONO) has the potential to greatly contribute to the atmospheric oxidation capacity. Increased attention has been paid to in-particle nitrite or nitrous acid, N(III), as one of the HONO sources. However, sources and formation mechanisms of N(III) remain uncertain. Here, we study a much less examined reaction of Fe(II) and nitrate as a source of N(III). The N(III) production was indirectly probed by its multiphase reaction with SO2 for sulfate production. Particles containing nitrate and Fe(III) were irradiated for generating Fe(II). Sulfate production was enhanced by the presence of UV and organic compounds likely because of the enhanced redox cycle between Fe(II) and Fe(III). Sulfate production rate increases with the concentration of iron-organic complexes in nitrate particles. Similarly, higher concentrations of iron-organic complexes yield higher nitrate decay rates. The estimated production rates of N(III) under simulated conditions in our study vary from 0.1 to 3.0 μg m-3 of air h-1. These values are comparable to HONO production rates of 0.2-1.6 ppbv h-1, which fall in the values reported in laboratory and field studies. The present study highlights a synergistic effect of the coexistence of iron-organic complexes and nitrate under irradiation as a source of N(III).
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Affiliation(s)
- Masao Gen
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong 999077, China
| | - Ruifeng Zhang
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong 999077, China
| | - Chak Keung Chan
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong 999077, China
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9
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Liang Z, Zhang R, Gen M, Chu Y, Chan CK. Nitrate Photolysis in Mixed Sucrose-Nitrate-Sulfate Particles at Different Relative Humidities. J Phys Chem A 2021; 125:3739-3747. [PMID: 33899478 DOI: 10.1021/acs.jpca.1c00669] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Atmospheric particles can be viscous. The limitation in diffusion impedes the mass transfer of oxidants from the gas phase to the particle phase and hinders multiphase oxidation processes. On the other hand, nitrate photolysis has been found to be effective in producing oxidants such as OH radicals within the particles. Whether nitrate photolysis can effectively proceed in viscous particles and how it may affect the physicochemical properties of the particle have not been much explored. In this study, we investigated particulate nitrate photolysis in mixed sucrose-nitrate-sulfate particles as surrogates of atmospheric viscous particles containing organic and inorganic components as a function of relative humidity (RH) and the molar fraction of sucrose to the total solute (FSU) with an in situ micro-Raman system. Sucrose suppressed nitrate crystallization, and high photolysis rate constants (∼10-5 s-1) were found, irrespective of the RH. For FSU = 0.5 and 0.33 particles under irradiation at 30% RH, we observed morphological changes from droplets to the formation of inclusions and then likely "hollow" semisolid particles, which did not show Raman signal at central locations. Together with the phase states of inorganics indicated by the full width at half-maxima (FWHM), images with bulged surfaces, and size increase of the particles in optical microscopic imaging, we inferred that the hindered diffusion of gaseous products (i.e., NOx, NOy) from nitrate photolysis is a likely reason for the morphological changes. Atmospheric implications of these results are also presented.
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Affiliation(s)
- Zhancong Liang
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue 83, Kowloon, Hong Kong, China
| | - Ruifeng Zhang
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue 83, Kowloon, Hong Kong, China
| | - Masao Gen
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Yangxi Chu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Chak K Chan
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue 83, Kowloon, Hong Kong, China
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Zhang R, Gen M, Fu TM, Chan CK. Production of Formate via Oxidation of Glyoxal Promoted by Particulate Nitrate Photolysis. Environ Sci Technol 2021; 55:5711-5720. [PMID: 33861585 DOI: 10.1021/acs.est.0c08199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Particulate nitrate photolysis can produce oxidants (i.e., OH, NO2, and NO2-/HNO2) in aqueous droplets and may play a potential role in increased atmospheric oxidative capacity. Our earlier works have reported on the SO2 oxidation promoted by nitrate photolysis to produce sulfate. Here, we used glyoxal as a model precursor to examine the role of particulate nitrate photolysis in the formation of secondary organic aerosol (SOA) from particle-phase oxidation of glyoxal by OH radicals. Particles containing sodium nitrate and glyoxal were irradiated at 300 nm. Interestingly, typical oxidation products of oxalic acid, glyoxylic acid, and higher-molecular-weight products reported in the literature were not found in the photooxidation process of glyoxal during nitrate photolysis in the particle phase. Instead, formic acid/formate production was found as the main oxidation product. At glyoxal concentration higher than 3 M, we found that the formic acid/formate production rate increases significantly with increasing glyoxal concentration. Such results suggest that oxidation of glyoxal at high concentrations by OH radicals produced from nitrate photolysis in aqueous particles may not contribute significantly to SOA formation since formic acid is a volatile species. Furthermore, recent predictions of formic acid/formate concentration from the most advanced chemical models are lower than ambient observations at both the ground level and high altitude. The present study reveals a new insight into the production of formic acid/formate as well as a sink of glyoxal in the atmosphere, which may partially narrow the gap between model predictions and field measurements in both species.
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Affiliation(s)
- Ruifeng Zhang
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Masao Gen
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Tzung-May Fu
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Chak K Chan
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
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11
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Gen M, Ikeda A, Kawachi S, Shitaokoshi T, Matsuda YH, Kohama Y, Nomura T. Higher magnetic-field generation by a mass-loaded single-turn coil. Rev Sci Instrum 2021; 92:033902. [PMID: 33819992 DOI: 10.1063/5.0038732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Single-turn coil (STC) technique is a convenient way to generate ultrahigh magnetic fields of more than 100 T. During the field generation, the STC explosively destructs outward due to the Maxwell stress and Joule heating. Unfortunately, the STC does not work at its full potential because it has already expanded when the maximum magnetic field is reached. Here, we propose an easy way to delay the expansion and increase the maximum field by using a mass-loaded STC. By loading clay on the STC, the field profile drastically changes, and the maximum field increases by 4%. This method offers access to higher magnetic fields for physical property measurements.
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Affiliation(s)
- M Gen
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - A Ikeda
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - S Kawachi
- Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8503, Japan
| | - T Shitaokoshi
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Y H Matsuda
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Y Kohama
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - T Nomura
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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12
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Abstract
Megacities are metropolitan areas with populations over 10 million, and many of them are facing significant global environmental challenges such as air pollution. Intense economic and human activities in megacities result in air pollution emissions, inducing high levels of air pollutants in the atmosphere that harm human health, cause regional haze and acid deposition, damage crops, influence regional air quality, and contribute to climate change. Since the Great London Smog and the first recognized episode of Los Angeles photochemical smog seventy years ago, substantial progress has been achieved in improving the scientific understanding of air pollution and in developing emissions reduction technologies and control measures. However, much remains to be understood about the complex processes of atmospheric transport and reaction mechanisms; the formation and evolution of secondary particles, especially those containing organic species; and the influence of emerging emissions sources and changing climate on air quality and health. Molina (DOI: ) has provided an excellent overview of the sources of emissions in megacities, atmospheric physicochemical processes, air quality trends and management, and the impacts on health and climate for the introductory lecture of this Faraday Discussion.
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Affiliation(s)
- Masao Gen
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
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13
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Bloss W, Brimblecombe P, Chen Y, Coe H, Gani S, Gen M, Grimmond S, Harrison R, McFiggans G, Mihaylova L, Pfrang C, Shi Z, Slater J, Srivastava D, Styring P, Velasco E, Wang P, Yu JZ. General discussion: Urban air quality; Meteorological influences and air quality trends. Faraday Discuss 2021; 226:191-206. [PMID: 33877223 DOI: 10.1039/d1fd90014e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Cheng C, Chan CK, Lee BP, Gen M, Li M, Yang S, Hao F, Wu C, Cheng P, Wu D, Li L, Huang Z, Gao W, Fu Z, Zhou Z. Single particle diversity and mixing state of carbonaceous aerosols in Guangzhou, China. Sci Total Environ 2021; 754:142182. [PMID: 33254891 DOI: 10.1016/j.scitotenv.2020.142182] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 08/14/2020] [Accepted: 09/02/2020] [Indexed: 06/12/2023]
Abstract
Many field studies have investigated the formation mechanisms of organic aerosol (OA) based on bulk analysis, yet the source and formation process of individual organic particles may be quite different due to the diversity of chemical composition and mixing state in single particles. Here we present the observation results of chemical composition and mixing state of carbonaceous single particles at an urban site in Guangzhou. The carbonaceous particles accounted for 74.6% of the total detected single particles, and were grouped into four types including elemental carbon-aged (EC-aged), elemental and organic carbon (ECOC), organic carbon-rich (OC-rich) and secondary ions-rich (SEC) particles. The formation of EC-aged particles was closely associated with the absorption of organics onto fresh EC particles from primary sources, and the further enrichment of organics in EC-aged particles resulted in the production of ECOC particles. In the daytime OC-rich and SEC particles were mainly produced from the photochemical reactions, while in the nighttime their sharp increases were found along with the enrichment of nitrate and organic nitrogen fragments, suggesting the heterogeneous formation of nitrate and organic nitrogen in OC-rich and SEC particles. The production rates of carbonaceous particles were also investigated in an episodic event, and the EC-aged particles showed the highest production rate compared to the other carbonaceous particles both in the daytime and nighttime, suggesting a significant role of EC in the formation and aging process of carbonaceous particles. The results from this work have revealed different formation processes and production rates of carbonaceous particles due to their diversity in mixing state, providing further insights into the formation mechanisms of OA in field studies.
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Affiliation(s)
- Chunlei Cheng
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for on-Line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Chak K Chan
- School of Energy and Environment, City University of Hong Kong, Hong Kong, China.
| | - Berto Paul Lee
- School of Energy and Environment, City University of Hong Kong, Hong Kong, China
| | - Masao Gen
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kanazawa 920-1192, Japan
| | - Mei Li
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for on-Line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China.
| | - Suxia Yang
- Institute for Environment and Climate Research, Jinan University, Guangzhou 510632, China
| | - Feng Hao
- Environmental Monitoring Center of Inner Mongolia Autonomous Region, Hohhot 010011, China
| | - Cheng Wu
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for on-Line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Peng Cheng
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for on-Line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Dui Wu
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for on-Line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Lei Li
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for on-Line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Zhengxu Huang
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for on-Line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Wei Gao
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for on-Line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Zhong Fu
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Zhen Zhou
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for on-Line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
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15
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Zheng H, Song S, Sarwar G, Gen M, Wang S, Ding D, Chang X, Zhang S, Xing J, Sun Y, Ji D, Chan CK, Gao J, McElroy MB. Contribution of Particulate Nitrate Photolysis to Heterogeneous Sulfate Formation for Winter Haze in China. Environ Sci Technol Lett 2020; 7:632-638. [PMID: 32984431 PMCID: PMC7510950 DOI: 10.1021/acs.estlett.0c00368] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Nitrate and sulfate are two key components of airborne particulate matter (PM). While multiple formation mechanisms have been proposed for sulfate, current air quality models commonly underestimate its concentrations and mass fractions during northern China winter haze events. On the other hand, current models usually overestimate the mass fractions of nitrate. Very recently, laboratory studies have proposed that nitrous acid (N(III)) produced by particulate nitrate photolysis can oxidize sulfur dioxide to produce sulfate. Here, for the first time, we parameterize this heterogeneous mechanism into the state-of-the-art Community Multi-scale Air Quality (CMAQ) model and quantify its contributions to sulfate formation. We find that the significance of this mechanism mainly depends on the enhancement effects (by 1-3 orders of magnitude as suggested by the available experimental studies) of nitrate photolysis rate constant (J NO 3 - ) in aerosol liquid water compared to that in the gas phase. Comparisons between model simulations and in-situ observations in Beijing suggest that this pathway can explain about 15% (assuming an enhancement factor (EF) of 10) to 65% (assuming EF = 100) of the model-observation gaps in sulfate concentrations during winter haze. Our study strongly calls for future research on reducing the uncertainty in EF.
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Affiliation(s)
- Haotian Zheng
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Shaojie Song
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Golam Sarwar
- Center for Environmental Measurement and Modeling, U.S. Environmental Protection Agency, 109 T.W. Alexander Drive, Research Triangle Park, NC, 27711, USA
| | - Masao Gen
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kanazawa 920-1192, Japan
| | - Shuxiao Wang
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Dian Ding
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Xing Chang
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Shuping Zhang
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
| | - Jia Xing
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Yele Sun
- State Key Laboratory of Atmospheric Boundary Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Dongsheng Ji
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Chak K Chan
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong 999077, China
| | - Jian Gao
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 10084, China
| | - Michael B McElroy
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
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16
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Gen M, Zhang R, Li Y, Chan CK. Multiphase Photochemistry of Iron-Chloride Containing Particles as a Source of Aqueous Chlorine Radicals and Its Effect on Sulfate Production. Environ Sci Technol 2020; 54:9862-9871. [PMID: 32668147 DOI: 10.1021/acs.est.0c01540] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Photolysis of iron chlorides is a well-known photolytic source of Cl• in environmental waters. However, the role of particulate chlorine radicals (Cl• and Cl2•-) in their multiphase oxidative potential has been much less explored. Herein, we examine the effect of Cl•/Cl2•- produced from photolysis of particulate iron chlorides on atmospheric multiphase oxidation. As a model system, experiments on multiphase oxidation of SO2 by Cl•/Cl2•- were performed. Fast sulfate production from SO2 oxidation was observed with reactive uptake coefficients of ∼10-5, comparable to the values necessary for explaining the observations in the haze events in China. The experimental and modeling results found a good positive correlation between the uptake coefficient, γSO2, and the Cl• production rate, d[Cl•]/dt, as γSO2 = 5.3 × 10-6 × log(d[Cl•]/dt) + 4.9 × 10-5. When commonly found particulate dicarboxylic acids (oxalic acid or malonic acid) were added, sulfate production was delayed due to the competition of Fe3+ between chloride and the dicarboxylic acid for its complexation at the initial stage. After the delay, comparable sulfate production was observed. The present study highlights the importance of photochemistry of particulate iron chlorides in multiphase oxidation processes in the atmosphere.
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Affiliation(s)
- Masao Gen
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Ruifeng Zhang
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Yongjie Li
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - Chak K Chan
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
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17
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Chen X, Chu Y, Lee AKY, Gen M, Kasthuriarachchi NY, Chan CK, Li YJ. Relative Humidity History Affects Hygroscopicity of Mixed Particles of Glyoxal and Reduced Nitrogenous Species. Environ Sci Technol 2020; 54:7097-7106. [PMID: 32428397 DOI: 10.1021/acs.est.0c00680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The relative humidity (RH) history that manifests the cycling of dehydration (water evaporation) and hydration (water uptake) may affect particle-phase reactions, products from which have strong influences on the physical properties and thus climatic effects of atmospheric particles. Using single-trapped particles, we show herein hygroscopic growths of mixed particles with reactive species undergoing three types of RH cycles, simulating different degrees of particle-phase reactions in the atmosphere. The reactive species are the widely known α-dicarbonyl glyoxal (GLY), and five reduced nitrogenous species, ammonium sulfate (AS), glycine (GC), l-alanine (AL), dimethylamine (DMA), and diethylamine (DEA). The results showed that the mixed particles after reactions generally had altered efflorescence relative humidity (ERH) and deliquescence relative humidity (DRH) values and reduced hygroscopic growths at moderately high RH (>80%) conditions. For example, with an additional slow drying step, the mean mass growth factors at 90% RH during dehydration dropped from 2.56 to 2.02 for GC/GLY mixed particles and from 2.45 to 1.23 for AL/GLY mixed particles. The reduced hygroscopicity with more RH cycling will thus lead to less efficient light scattering of the mixed particles, thereby resulting in less cooling and exacerbating direct heating due to light absorption by the products formed.
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Affiliation(s)
- Xi Chen
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau, People's Republic of China
| | - Yangxi Chu
- School of Energy and Environment, City University of Hong Kong, Hong Kong, People's Republic of China
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, People's Republic of China
| | - Alex K Y Lee
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore
| | - Masao Gen
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kanazawa 920-1192, Japan
| | | | - Chak K Chan
- School of Energy and Environment, City University of Hong Kong, Hong Kong, People's Republic of China
| | - Yong Jie Li
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau, People's Republic of China
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18
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Kusdianto K, Gen M, Wada M, Winardi S, Lenggoro IW. Deposition of ultrasonic nebulized aerosols onto a hydrophilic surface. Mal J Fund Appl Sci 2020. [DOI: 10.11113/mjfas.v16n3.1608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The effect of chemical treatment of a metallic substrate on the deposition of aerosols generated by an ultrasonic nebulizer was investigated. A single substrate with areas having different “level” of hydrophilicity (or hydrophobicity) was used as a model surface. The treated (more hydrophilic) area became more negatively-charged based on a surface electric potential meter. A low-pressure analysis method (electron-microscope image) and ordinary pressure methods (Raman spectroscopy and X-ray fluorescence) analytical results indicated that in comparison with the untreated area, the treated area trapped more particles in the case of the deposition of “wet” aerosols. In the case of the deposition of more “dry” aerosols, the untreated area trapped more particles rather than that of the treated one. The efficiency of particles deposition not only depended on the degree of hydrophilicity (or hydrophobicity) of the surface but also due to the conditions (wet or dry) of incoming aerosols.
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19
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Wexler AS, Patel K, Gen M, Chan CK. Reconciling Measurement and Prediction of Free and Solvated Water in Solution. ACS Omega 2020; 5:8754-8765. [PMID: 32337437 PMCID: PMC7178779 DOI: 10.1021/acsomega.0c00311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/18/2020] [Indexed: 06/11/2023]
Abstract
In 2019, Wexler showed that, by applying Raoult's law rigorously to aqueous solutions and properly accounting for hydration of solutes, equations can be derived that accurately describe solute and solvent activity over the full range of concentrations from infinitely dilute to pure solutes. One feature of this theory is that it also predicts the amount of water that is free and the amount that is bound to the solute. In 2004 and 2005, Choi and co-workers used an electrodynamic balance to measure (i) the concentration of a range of organic and electrolyte solutes as a function of water activity and (ii) the amount of free and bound water in these solutions using the fluorescence of pyranine as a probe. In the current work, we compare the predictions of Wexler's theory to the measurements of Choi. After the adjustments to the amount of free water obtained by these measurements, the predictions of Wexler's theory match the measurements of Choi. The potential reasons for the adjustments are discussed.
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Affiliation(s)
- Anthony S. Wexler
- Air
Quality Research Center and Departments of Mechanical and Aerospace
Engineering, Civil and Environmental Engineering, and Land, Air and
Water Resources, University of California, Davis, California 95616, United States
| | - Kunal Patel
- Department
of Chemical Engineering, University of California, Davis, California 95616, United States
| | - Masao Gen
- Faculty
of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Chak K. Chan
- School
of Energy and Environment, City University
of Hong Kong, Kowloon, Hong Kong, China
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20
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Zhang R, Gen M, Huang D, Li Y, Chan CK. Enhanced Sulfate Production by Nitrate Photolysis in the Presence of Halide Ions in Atmospheric Particles. Environ Sci Technol 2020; 54:3831-3839. [PMID: 32126769 DOI: 10.1021/acs.est.9b06445] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Heterogeneous oxidation of SO2 is an effective production pathway of sulfate in the atmosphere. We recently reported a novel pathway for the heterogeneous oxidation of SO2 by in-particle oxidants (OH, NO2, and NO2-/HNO2) produced from particulate nitrate photolysis (Environ. Sci. Technol. 2019, 53, 8757-8766). Particulate nitrate is often found to coexist with chloride and other halide ions, especially in aged sea-salt aerosols and combustion aerosols. Reactive uptake experiments of SO2 with UV-irradiated nitrate particles showed that sulfate production rates were enhanced by a factor of 1.4, 1.3, and 2.0 in the presence of Cl-, Br-, and I-, respectively, compared to those in the absence of halide ions. The larger sulfate production was attributed to enhanced nitrate photolysis promoted by the increased incomplete solvation of nitrate at the air-particle interface due to the presence of surface-active halide ions. Modeling results based on the experimental data showed that the nitrate photolysis rate constants increased by a factor of 2.0, 1.7, and 3.7 in the presence of Cl-, Br-, and I-, respectively. A linear relation was found between the nitrate photolysis rate constant, jNO3-, and the initial molar ratio of Cl- to NO3-, [Cl-]0/[NO3-]0, as jNO3- = 9.7 × 10-5[Cl-]0/[NO3-]0 + 1.9 × 10-5 at [Cl-]0/[NO3-]0 below 0.2. The present study demonstrates that the presence of halide ions enhances sulfate production produced during particulate nitrate photolysis and provides insights into the enhanced formation of in-particle oxidants that may increase atmospheric oxidative capacity.
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Affiliation(s)
- Ruifeng Zhang
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Masao Gen
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Dandan Huang
- Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Yongjie Li
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - Chak K Chan
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
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Mizukami M, Gen M, Hsu SY, Tsujii Y, Kurihara K. Dynamics of lubricious, concentrated PMMA brush layers studied by surface forces and resonance shear measurements. Soft Matter 2019; 15:7765-7776. [PMID: 31508654 DOI: 10.1039/c9sm01133a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We employed surface forces and resonance shear measurement (RSM) for studying the structure and properties of typical concentrated polymer brushes (CPBs) of poly(methylmethacrylate) (PMMA) in toluene, which are known to show very low friction. The surface forces measured between the silica surfaces bearing PMMA brush layers showed a steric repulsive force at distances between the silica surfaces of less than ca. 1050 nm (Donset). Upon retraction after compression of the PMMA brush layers, no adhesive force was observed. This indicated that the interpenetration of the polymer chain was not induced by the normal load. Based on the resonance shear measurement, the elastic (k2) and damping (viscous) (b2) parameters, which represent the dynamic properties, of the PMMA brush layers were obtained by analyzing the resonance curves. At distances below the Donset, the b2 value significantly increased and slightly decreased at the higher normal loads, and the k2 value monotonically increased with increasing load. These k2 and b2 values were greater than those obtained for a PMMA brush layer and a bare silica surface (PMMA-silica). This indicated that the mobility of the polymer chains for the PMMA-PMMA brush layers was more suppressed compared to that for the PMMA-silica, due to the interpenetration of the polymer chains. The interpenetration of the polymer chains, commonly not observed for CPBs, could be most probably induced by the application of both the normal load and oscillating shear motion. With increasing shear amplitude on the compressed PMMA-PMMA brushes (at L = 0.84, 1.34 and 4.28 mN), the b2 value first increased then decreased whilst the k2 value monotonically decreased. These tendencies can be explained by the change from the sticking condition due to interpenetration (high k2), small sliding under interpenetration (increase in b2, decrease in k2), and then smooth sliding by pulling out of interpenetrated polymer chains (decrease in b2 and k2). The obtained results indicated that the operating conditions are quite important for using polymer brush layers as tribological materials because they can exhibit both a high and low friction depending on the conditions such as the load and shear amplitude.
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Affiliation(s)
- Masashi Mizukami
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, 980-8577, Japan.
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Gen M, Zhang R, Huang DD, Li Y, Chan CK. Heterogeneous Oxidation of SO 2 in Sulfate Production during Nitrate Photolysis at 300 nm: Effect of pH, Relative Humidity, Irradiation Intensity, and the Presence of Organic Compounds. Environ Sci Technol 2019; 53:8757-8766. [PMID: 31241323 DOI: 10.1021/acs.est.9b01623] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Heterogeneous oxidation of SO2 is one of the promising mechanisms to account for high loading of sulfate during severe haze periods in China. Our earlier work reported on the SO2 oxidation by OH and NO2 produced during 250 nm nitrate photolysis (Environ. Sci. Technol. Lett. 2019, 6, 86-91). Here, we extend that work to examine sulfate production during nitrate photolysis at 300 nm irradiation, which can additionally generate NO2- or HNO2, N(III). Flow cell/in situ Raman experiments showed that the reactive uptake coefficient of SO2, γSO2, can be expressed as γSO2 = 1.64 × pNO3-, where pNO3- is the nitrate photolysis rate in the range of (1.0-8.0) × 10-5 M s-1. Our kinetic model with the pNO3- predicts that N(III) is the main contributor to the SO2 oxidation, followed by NO2 contribution. Furthermore, the addition of OH scavengers (e.g., glyoxal or oxalic acid) does not suppress the sulfate production because of the reduced N(III)-consuming reactions and the high particle pH sustained by their presence. Our calculations illustrate that under characteristic haze conditions, the nitrate photolysis mechanism can produce sulfate at ∼1 μg m-3 h-1 at pH 4-6 and pNO3- = 10-5 M s-1. The present study highlights the importance of in-particle nitrate photolysis in heterogeneous oxidation of SO2 by reactive nitrogen (NO2-/HNO2 and NO2) under atmospherically relevant actinic irradiation. However, the nitrate photolysis rate constant needs to be better constrained for ambient aerosols.
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Affiliation(s)
- Masao Gen
- School of Energy and Environment , City University of Hong Kong , Tat Chee Avenue , Kowloon , Hong Kong , China
| | - Ruifeng Zhang
- School of Energy and Environment , City University of Hong Kong , Tat Chee Avenue , Kowloon , Hong Kong , China
| | - Dan Dan Huang
- Shanghai Academy of Environmental Sciences , Shanghai 200233 , China
| | - Yongjie Li
- Department of Civil and Environmental Engineering, Faculty of Science and Technology , University of Macau , Macau 999078 , China
| | - Chak K Chan
- School of Energy and Environment , City University of Hong Kong , Tat Chee Avenue , Kowloon , Hong Kong , China
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Gen M, Huang DD, Chan CK. Reactive Uptake of Glyoxal by Ammonium-Containing Salt Particles as a Function of Relative Humidity. Environ Sci Technol 2018; 52:6903-6911. [PMID: 29775291 DOI: 10.1021/acs.est.8b00606] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Reactions between dissolved ammonia and carbonyls, which form light-absorbing species in atmospheric particles, can be accelerated by actively removing water from the reaction system. Here, we examine the effects of relative humidity (RH) on the reactive uptake of glyoxal (Gly) by aqueous particles of ammonium sulfate (AS), ammonium bisulfate, sodium sulfate, magnesium sulfate, ammonium nitrate (AN), and sodium nitrate. In situ Raman analysis was used to quantify particle-phase Gly and a colored product, 2,2'-biimidazole (BI), as a function of uptake time. Overall, the Gly uptake rate increases with decreasing RH, reflecting the "salting-in" effect. The BI formation rate increases significantly with decreasing RH or aerosol liquid water (ALW). Compared to that at 75% RH, the BI formation rate is enhanced by factors of 29 at 60% RH and 330 at 45% RH for AS particles and 65 at 60% RH, 210 at 45% RH, and 460 at 30% RH for AN particles. These enhancement factors are much larger than those estimated from increased reactant concentrations due to decreases in RH and ALW alone. We postulate that the reduction in ALW at low RH increases the Gly uptake rate via the "salting-in" effect and the BI formation rate by facilitating dehydration reactions.
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Affiliation(s)
- Masao Gen
- School of Energy and Environment , City University of Hong Kong , Tat Chee Avenue , Kowloon, Hong Kong , China
| | - Dan Dan Huang
- School of Energy and Environment , City University of Hong Kong , Tat Chee Avenue , Kowloon, Hong Kong , China
| | - Chak K Chan
- School of Energy and Environment , City University of Hong Kong , Tat Chee Avenue , Kowloon, Hong Kong , China
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Saallah S, Naim MN, Lenggoro IW, Mokhtar MN, Abu Bakar NF, Gen M. Immobilisation of cyclodextrin glucanotransferase into polyvinyl alcohol (PVA) nanofibres via electrospinning. ACTA ACUST UNITED AC 2016; 10:44-48. [PMID: 28352523 PMCID: PMC5040860 DOI: 10.1016/j.btre.2016.03.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/07/2016] [Accepted: 03/07/2016] [Indexed: 11/16/2022]
Abstract
Fabrication of enzyme-carrying polymeric nanofibers by electrospinning. PVA nanofibers structure and size were not affected by the addition of enzyme. The electrospun CGTase/PVA nanofibers show excellent immobilisation efficiency.
Immobilisation of cyclodextrin glucanotransferase (CGTase) on nanofibres was demonstrated. CGTase solution (1% v/v) and PVA (8 wt%) solution were mixed followed by electrospinning (−9 kV, 3 h). CGTase/PVA nanofibres with an average diameter of 176 ± 46 nm were successfully produced. The nanofibres that consist of immobilised CGTase were crosslinked with glutaraldehyde vapour. A CGTase/PVA film made up from the same mixture and treated the same way was used as a control experiment. The immobilised CGTase on nanofibres showed superior performance with nearly a 2.5 fold higher enzyme loading and 31% higher enzyme activity in comparison with the film.
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Affiliation(s)
- Suryani Saallah
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan; Biotechnology Research Institute, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia
| | - M Nazli Naim
- Department of Process and Food Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - I Wuled Lenggoro
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan; Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan
| | - Mohd Noriznan Mokhtar
- Department of Process and Food Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Noor Fitrah Abu Bakar
- Faculty of Chemical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
| | - Masao Gen
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan; Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
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Gen M, Lenggoro IW. Probing a dip-coated layer of organic molecules by an aerosol nanoparticle sensor with sub-100 nm resolution based on surface-enhanced Raman scattering. RSC Adv 2015. [DOI: 10.1039/c4ra03850a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A surface coated with organic molecules has been probed by a sub 100 nm resolution particulate sensor by surface-enhanced Raman scattering (SERS) technique.
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Affiliation(s)
- Masao Gen
- Graduate School of Bio-Applications and Systems Engineering (BASE)
- Tokyo University of Agriculture and Technology
- Koganei
- Japan
| | - I. Wuled Lenggoro
- Graduate School of Bio-Applications and Systems Engineering (BASE)
- Tokyo University of Agriculture and Technology
- Koganei
- Japan
- Department of Chemical Engineering
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Saallah S, Naim MN, Mokhtar MN, Abu Bakar NF, Gen M, Lenggoro IW. Transformation of cyclodextrin glucanotransferase (CGTase) from aqueous suspension to fine solid particles via electrospraying. Enzyme Microb Technol 2014; 64-65:52-9. [DOI: 10.1016/j.enzmictec.2014.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 06/17/2014] [Accepted: 06/21/2014] [Indexed: 10/25/2022]
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Gen M. [Effects of bisphosphonates on vitamin A-induced bone resorption in thyroparathyroidectomized rat]. Nihon Seikeigeka Gakkai Zasshi 1995; 69:1193-207. [PMID: 8568374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A bone resorption model in which osteoclasts were selectively activated was made by administering vitamin A--a bone resorption agent--to juvenile thyroparathyroidectomized rat. Inhibition of bone resorption by YM-175--a third generation bisphosphonate--was studied using this model based on bone histomorphometry of the proximal part of the tibia and on biochemical data. Six-week-old male SD rats were thyroparathyroidectomized (TPTX). On the 11th day following TPTX they were treated with vitamin A (etretinate). In the calcitonin group, salmon calcitonin or its vehicle was added, and in the bisphosphonate group, YM-175 or its vehicle was added. They were sacrificed on the 21st day following TPTX. Calcitonin was used to confirm its inhibitory activity of bone resorption in this model. Cancellous bone in the epiphysis was subjected to histomorphometry using tetracycline labeling or TRAP staining, and the number of primary trabeculae at the metaphysis was counted to evaluate bone resorption activity. Serum calcium, phosphorus, urinary calcium, phosphorus, pyridinoline and deoxypyridinoline were measured for biochemical analysis. YM-175 did not change any bone formation parameters in the histomorphometry of the epiphysis, while it significantly decreased resorption parameters both histomorphometrically and biochemically. Primary trabeculae at the metaphysis were found to be longer and denser after administration of YM-175. The effect of YM-175 as a bone resorption inhibitor was observed even in a short duration experiment. There was no damage to mineralization, and no inhibiting effect was observed on bone formation. Similar results were observed by calcitonin. YM-175 was concluded to be an inhibitor of bone resorption caused by vitamin A administration.
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Affiliation(s)
- M Gen
- Department of Orthopedic Surgery, Akita University School of Medicine, Japan
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Iyama K, Watahiki H, Saitou M, Tatami M, Dodo S, Yamamoto H, Higuchi T, Gen M, Nagata H, Ogawa H. [A case of actinomycosis of the greater omentum]. Nihon Shokakibyo Gakkai Zasshi 1995; 92:894-8. [PMID: 7783384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- K Iyama
- Department of Gastroenterology, Seirei Mikatahara General Hospital
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Affiliation(s)
- D Browne
- Oregon Health Sciences University, Portland 97201
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Nagatani M, Mori S, Takimoto N, Arita N, Ushio Y, Hayakawa T, Gen M, Uozumi T, Mogami H. Primary myxoma in the pituitary fossa: case report. Neurosurgery 1987; 20:329-31. [PMID: 3561744 DOI: 10.1227/00006123-198702000-00024] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A case of primary myxoma in the pituitary fossa is described. The tumor presented as an intrasellar and suprasellar mass and was successfully removed during a transsphenoidal operation. It was verified as a myxoma by histopathological studies, and there was no evidence that it was a metastasis. This is thought to be the first report of this tumor occurring in the pituitary fossa.
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Abstract
Six prolactinoma patients were studied endocrinologically and their tumors were examined histologically after long term bromocriptine therapy. In patient 1 with a large prolactinoma, a marked reduction in size and a remarkable decrease in elevated serum PRL levels occurred after bromocriptine treatment for 8 months. The histological findings consisted of two components, i.e. shrunken island-like cell nests and acellular spaces. Some degenerative and necrotic tumor cells, hyaline substance, and fibrosis were observed with light and electron microscopy in these acellular spaces. Island-like cell nests consisted of atrophic cells having disproportionally scanty cytoplasm. The same histological findings were observed in four other patients. However, in another patient whose tumor decreased in size only slightly during bromocriptine therapy, the specimen had few acellular spaces. Thus, long term bromocriptine treatment of patients with prolactinomas may result in necrosis of some adenoma cells in some patients.
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Shima T, Okada Y, Gen M, Uozumi T. [A case of internal carotid dolichoectasia]. No Shinkei Geka 1984; 12:407-12. [PMID: 6462350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A 50-year-old woman noticed right motor and sensory paralysis in the morning of December 15, 1978, which improved gradually to be able to walk during 20 days. She had recurrence of incomplete paralysis of right extremities with speech disturbance and admitted to our department on April 7. Neurological examination revealed right hemiparesis. Plain skull rentogenorgram showed a calcification extending posteriorly from the left anterior clinoid process. CT scan showed a mass lesion located at the left frontal lobe to the ambient cistern. The mass lesion showed high density, but its midportion was isodensity. The left carotid angiogram demonstrated abnormally curved, tortuous and dilated internal carotid artery at the intracavernous portion (C3) to bifurcation (C1). The cerebral circulation time was greatly delayed, which regained about 6 seconds for the visualization of the distal portion of the middle cerebral artery. On the basis of the above, we considered that the first right hemiparesis was due to emboli produced in the dolichoectasia and the following progressive stroke was attributable to the low perfusion demonstrated by a great delay of circulation time. The operation was performed to trap the dolichoectasia after STA-MCA anastomosis. However, trapping procedure was very difficult because of hardness of the distal portion of the involved artery. Therefore, surgery was concluded with STA-MCA anastomosis and only proximal internal carotid clipping. The postoperative angiography demonstrated well functional anastomosis and obliteration of dolichoectasia. She discharged on improvement of her condition on the 23rd day after operation. CT scan performed 6 months after operations showed the mass lesion to have become definitely reduced in size. The application of bypass surgery to the internal carotid dolichoectasia was reported with review of the literatures.
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Muraki K, Nishi Y, Usui T, Sakoda K, Gen M. [Pituitary dwarfism caused by transsphenoidal meningoencephalocele]. Horumon To Rinsho 1983; 31 Suppl:17-9. [PMID: 6616908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Gen M, Uozumi T, Shinohara S, Naito M, Ito A, Mori S, Kajiwara H. Does bromocriptine have a cytocidal effect on prolactinoma cells? Report of a case. Neurol Med Chir (Tokyo) 1983; 23:61-5. [PMID: 6188984 DOI: 10.2176/nmc.23.61] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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Kiya K, Sakoda K, Gen M, Harada K, Uozumi T, Ito H. [A case of aspergillotic meningoencephalitis associated with trigeminal neuralgia]. No Shinkei Geka 1982; 10:861-6. [PMID: 7133307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A case of aspergillotic meningoencephalitis associated with trigeminal neuralgia was reported. The patient, a 41-year-old female, was admitted to our hospital on Nov. 20, 1977 with the chief complaint of right trigeminal neuralgia. On admission right facial paresthesia and right abducens palsy were found. The skull x-ray and tomogram showed enlargement of the right superior orbital fissure. Ct scan revealed an irregular high density around the right superior orbital fissure. The examination of spinal fluid showed 75 mg/dl protein, 72 mg/dl sugar and 11 cells. A biopsy of the mass and trigeminal rhizotomy were performed on Dec. 21, 1977. Microscopically, the specimen was composed of nonspecific granulomatous inflammatory tissue. Thereafter, loss of visual acuity, total ophthalmoplegia and facial paresis gradually appeared on the right side with high fever elevation. Immunologically, peripheral blood lymphocytes responded normally to PHA and PWM, but numbers of lymphocytes showed a tendancy of decrease with deterioration. On the other hand, serum IgG and IgM levels were rather increased. CT scan showed that an irregular high density mass extended to the right orbital apex and the pterygoid fossa. Spinal fluid revealed 260 mmH2O pressure with 76 mg/dl protein, 55 mg/dl sugar and 293 cells, but no organisms were demonstrated. Four months after the operation, swelling of the right subtemporal region became remarkable, in which region a puncture revealed much pus retention, and Aspergillus fumigatus was cultured from the aspirated pus. The patient became comatose and died on May 20, 1978. Autopsy showed thick, yellowish green pseudomembranes covering from the right temporal tip to the basal cistern. The both of cerebral hemispheres were swollen and revealed multiple small softenings all over the brain. Small hemorrhage occupying the right temporal subcortex and microabscess located in the left thalamus were also seen. Microscopical examination disclosed that the pseudomembrane was composed of the necrotizing suppurative inflammation with branched septate hypha of Aspergillus. There have been a few reports of aspergillotic meningoencephalitis associated with trigeminal neuralgia and enlargement of the superior orbital fissure like this case. Some discussion was made on the importance for the diagnosis of aspergillosis to perform fungal culture and histological examination of materials obtained from the inflammatory site, and immunological data of this case was also presented.
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