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1. Biosystems Design to Accelerate C ₃ -to-CAM Progression

   https://doi.org/10.34133/2020/3686791  

   Yuan, Guoliang; Hassan, Md. Mahmudul; Liu, Degao; Lim, Sung Don; Yim, Won Cheol; Cushman, John C.; Markel, Kasey; Shih, Patrick M.; Lu, Haiwei; Weston, David J.; et al (October 2020, BioDesign Research)

   Global demand for food and bioenergy production has increased rapidly, while the area of arable land has been declining for decades due to damage caused by erosion, pollution, sea level rise, urban development, soil salinization, and water scarcity driven by global climate change. In order to overcome this conflict, there is an urgent need to adapt conventional agriculture to water-limited and hotter conditions with plant crop systems that display higher water-use efficiency (WUE). Crassulacean acid metabolism (CAM) species have substantially higher WUE than species performing C 3 or C 4 photosynthesis. CAM plants are derived from C 3 photosynthesis ancestors. However, it is extremely unlikely that the C 3 or C 4 crop plants would evolve rapidly into CAM photosynthesis without human intervention. Currently, there is growing interest in improving WUE through transferring CAM into C 3 crops. However, engineering a major metabolic plant pathway, like CAM, is challenging and requires a comprehensive deep understanding of the enzymatic reactions and regulatory networks in both C 3 and CAM photosynthesis, as well as overcoming physiometabolic limitations such as diurnal stomatal regulation. Recent advances in CAM evolutionary genomics research, genome editing, and synthetic biology have increased the likelihood of successful acceleration of C 3 -to-CAM progression. Here, we first summarize the systems biology-level understanding of the molecular processes in the CAM pathway. Then, we review the principles of CAM engineering in an evolutionary context. Lastly, we discuss the technical approaches to accelerate the C 3 -to-CAM transition in plants using synthetic biology toolboxes. 

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2. p-Type BiVO ₄ for Solar O ₂ Reduction to H ₂ O ₂

   https://doi.org/10.1021/jacs.4c13290  

   Seo, Daye; Somjit, Vrindaa; Wi, Dae Han; Galli, Giulia; Choi, Kyoung-Shin (January 2025, Journal of the American Chemical Society)
3. Conversion of Catechol to 4-Nitrocatechol in Aqueous Microdroplets Exposed to O ₃ and NO ₂

   https://doi.org/10.1021/acsestair.3c00001  

   Rana, Md Sohel; Bradley, Seth T.; Guzman, Marcelo I. (February 2024, ACS ES&T Air)

   Catechol is a widespread atmospheric dihydroxybenzene present in vehicle emissions, biomass burning, and combustion pollution plumes. Although the daytime reactivity of catechol is controlled by ozone (O3) and hydroxyl radicals (HO), the action of nitrate radicals (NO3) on the surface of aqueous atmospheric particles should become significant at night. This work simulates nighttime interfacial chemistry between hydrated catechol and adsorbed NO3 to form 4-nitrocatechol during experiments lasting ≤1 μs. Surface-sensitive online electrospray ionization mass spectrometry (OESI-MS) examines the reaction on the water surface under variable ratios of [NO2] and [O3]. The produced 4-nitrocatechol is quantified by a standard addition in real-time experiments under [NO2]:[O3] ratios of 1:1, 2:1, 3:1, and 4:1. Three mechanisms contribute to produce 4-nitrocatechol: (1) electron and proton transfers from catechol to NO3, forming a semiquinone radical, (2) electrophilic NO3 attack to the ring to yield a cyclohexadienyl radical intermediate, and (3) electrophilic attack to the ring by nitronium ion (NO2+) formed at the interface of water by colliding N2O5(g) at low pH. Ozonolysis competes strongly with nitration when using [NO2]:[O3] ratios 1:1 or smaller. Instead, nighttime chemistry under higher molar ratios proceeds mainly by nitration with a maximum yield of 0.90 for [NO2]:[O3] = 4:1. 

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4. Planar defect-driven electrocatalysis of CO ₂ -to-C ₂ H ₄ conversion

   https://doi.org/10.1039/d1ta02565a  

   Li, Zhengyuan; Fang, Yanbo; Zhang, Jianfang; Zhang, Tianyu; Jimenez, Juan D.; Senanayake, Sanjaya D.; Shanov, Vesselin; Yang, Shize; Wu, Jingjie (January 2021, Journal of Materials Chemistry A)

   null (Ed.)

   The selectivity towards a specific C 2+ product, such as ethylene (C 2 H 4 ), is sensitive to the surface structure of copper (Cu) catalysts in carbon dioxide (CO 2 ) electro-reduction. The fundamental understanding of such sensitivity can guide the development of advanced electrocatalysts, although it remains challenging at the atomic level. Here we demonstrated that planar defects, such as stacking faults, could drive the electrocatalysis of CO 2 -to-C 2 H 4 conversion with higher selectivity and productivity than Cu(100) facets in the intermediate potential region (−0.50 ∼ −0.65 V vs. RHE). The unique right bipyramidal Cu nanocrystals containing a combination of (100) facets and a set of parallel planar defects delivered 67% faradaic efficiency (FE) for C 2 H 4 and a partial current density of 217 mA cm −2 at −0.63 V vs. RHE. In contrast, Cu nanocubes with exclusive (100) facets exhibited only 46% FE for C 2 H 4 and a partial current density of 87 mA cm −2 at an identical potential. Both ex situ CO temperature-programmed desorption and in situ Raman spectroscopy analysis implied that the stronger *CO adsorption on planar defect sites facilitates CO generation kinetics, which contributes to a higher surface coverage of *CO and in turn an enhanced reaction rate of C–C coupling towards C 2+ products, especially C 2 H 4 . 

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5. Flux Synthesis of MgNi ₂ Bi ₄ and Its Structural Relationship to NiBi ₃

   https://doi.org/10.1021/acs.inorgchem.9b03196  

   Hertz, Mary B.; Baumbach, Ryan E.; Latturner, Susan E. (January 2020, Inorganic Chemistry)