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1. Observations of new particle formation, modal growth rates, and direct emissions of sub-10 nm particles in an urban environment.

   https://doi.org/doi.org/10.1016/j.atmosenv.2020.117835  

   Zimmerman, A. ( January 2020 , Atmospheric environment)

   null (Ed.)
2. Structural and Electronic Influences on Rates of Tertpyridine−Amine Co III −H Formation During Catalytic H 2 Evolution in an Aqueous Environment

   https://doi.org/10.1002/cphc.202100295  

   DiMarco, Brian N. ; Polyansky, Dmitry E. ; Grills, David C. ; Wang, Ping ; Kuwahara, Yutaka ; Zhao, Xuan ; Fujita, Etsuko ( June 2021 , ChemPhysChem)

   In this work, the differences in catalytic performance for a series of Co hydrogen evolution catalysts with different pentadentate polypyridyl ligands (L), have been rationalized by examining elementary steps of the catalytic cycle using a combination of electrochemical and transient pulse radiolysis (PR) studies in aqueous solution. Solvolysis of the [Co^II−Cl]⁺species results in the formation of [Co^II(κ⁴‐L)(OH₂)]²⁺. Further reduction produces [Co^I(κ⁴‐L)(OH₂)]⁺, which undergoes a rate‐limiting structural rearrangement to [Co^I(κ⁵‐L)]⁺before being protonated to form [Co^III−H]²⁺. The rate of [Co^III−H]²⁺formation is similar for all complexes in the series. UsingE_1/2values of various Co species and pK_avalues of [Co^III−H]²⁺estimated from PR experiments, we found that while the protonation of [Co^III−H]²⁺is unfavorable, [Co^II−H]⁺reacts with protons to produce H₂. The catalytic activity for H₂evolution tracks the hydricity of the [Co^II−H]⁺intermediate.

    

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3. Synergetic Effects of Isoprene and HO x on Biogenic New Particle Formation

   https://doi.org/10.1029/2023GL103545  

   Tiszenkel, Lee ; Lee, Shan‐Hu ( July 2023 , Geophysical Research Letters)

   New particle formation (NPF) has been observed at various locations, but NPF does not occur in isoprene‐dominant forests. Recent laboratory studies were conducted to understand the role of isoprene in biogenic NPF, and these studies show that isoprene can suppress biogenic NPF, with contradicting theories. To reconcile these discrepancies, we conducted flow tube experiments of biogenic nucleation under a wide range of isoprene over monoterpene carbon ratios (R) and oxidant conditions (OH vs. ozone). Our results show isoprene either suppresses or enhances biogenic NPF, depending onRand oxidation regimes, demonstrating the synergetic effects of isoprene and HO_x(OH and HO₂) on biogenic NPF. Whereas the suppression of NPF by isoprene is due to the product suppression effects of monoterpene dimers (C20), RO₂ + HO₂termination reactions also play important roles in suppressing the dimer formation, another likely process to suppress NPF in the atmosphere.

    

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4. New particle formation from sulfuric acid and amines: Comparison of monomethylamine, dimethylamine, and trimethylamine: Particle Formation From Different Amines

   https://doi.org/10.1002/2017JD026501  

   Olenius, Tinja ; Halonen, Roope ; Kurtén, Theo ; Henschel, Henning ; Kupiainen-Määttä, Oona ; Ortega, Ismael K. ; Jen, Coty N. ; Vehkamäki, Hanna ; Riipinen, Ilona ( July 2017 , Journal of Geophysical Research: Atmospheres)
5. Particle cycling rates at Station P as estimated from the inversion of POC concentration data

   https://doi.org/10.1525/elementa.2021.00018  

   Amaral, Vinícius J. ; Lam, Phoebe J. ; Marchal, Olivier ; Roca-Martí, Montserrat ; Fox, James ; Nelson, Norman B. ( January 2022 , Elementa: Science of the Anthropocene)

   Particle cycling rates in marine systems are difficult to measure directly, but of great interest in understanding how carbon and other elements are distributed throughout the ocean. Here, rates of particle production, aggregation, disaggregation, sinking, remineralization, and transport mediated by zooplankton diel vertical migration were estimated from size-fractionated measurements of particulate organic carbon (POC) concentration collected during the NASA EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) cruise at Station P in summer 2018. POC data were combined with a particle cycling model using an inverse method. Our estimates of the total POC settling flux throughout the water column are consistent with those derived from thorium-234 disequilibrium and sediment traps. A budget for POC in two size fractions, small (1–51 µm) and large (> 51 µm), was produced for both the euphotic zone (0–100 m) and the upper mesopelagic zone (100–500 m). We estimated that POC export at the base of the euphotic zone was 2.2 ± 0.8 mmol m−2 d−1, and that both small and large particles contributed considerably to the total export flux along the water column. The model results indicated that throughout the upper 500 m, remineralization leads to a larger loss of small POC than does aggregation, whereas disaggregation results in a larger loss of large POC than does remineralization. Of the processes explicitly represented in the model, zooplankton diel vertical migration is a larger source of large POC to the upper mesopelagic zone than the convergence of large POC due to particle sinking. Positive model residuals reveal an even larger unidentified source of large POC in the upper mesopelagic zone. Overall, our posterior estimates of particle cycling rate constants do not deviate much from values reported in the literature, i.e., size-fractionated POC concentration data collected at Station P are largely consistent with prior estimates given their uncertainties. Our budget estimates should provide a useful framework for the interpretation of process-specific observations obtained by various research groups in EXPORTS. Applying our inverse method to other systems could provide insight into how different biogeochemical processes affect the cycling of POC in the upper water column. 

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