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1. Quantum chemical modeling of organic enhanced atmospheric nucleation: A critical review

   https://doi.org/10.1002/wcms.1662  

   Elm, Jonas ; Ayoubi, Daniel ; Engsvang, Morten ; Jensen, Andreas Buchgraitz ; Knattrup, Yosef ; Kubečka, Jakub ; Bready, Conor J. ; Fowler, Vance R. ; Harold, Shannon E. ; Longsworth, Olivia M. ; et al ( May 2023 , WIREs Computational Molecular Science)

   Aerosol particles are important for our global climate, but the mechanisms and especially the relative importance of various vapors for new particles formation (NPF) remain uncertain. Quantum chemical (QC) studies on organic enhanced nucleation has for the past couple of decades attracted immense attention, but very little remains known about the exact organic compounds that potentially are important for NPF. Here we comprehensively review the QC literature on atmospheric cluster formation involving organic compounds. We outline the potential cluster systems that should be further investigated. Cluster formation involving complex multi‐functional organic accretion products warrant further investigations, but such systems are out of reach with currently applied methodologies. We suggest a “cluster of functional groups” approach to address this issue, which will allow for the identification of the potential structure of organic compounds that are involved in atmospheric NPF.

   This article is categorized under:

   Theoretical and Physical Chemistry > Reaction Dynamics and Kinetics

   Software > Quantum Chemistry

   Theoretical and Physical Chemistry > Thermochemistry

   Molecular and Statistical Mechanics > Molecular Interactions

    

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2. From Molecules to Molecular Surfaces. Exploiting the Interplay Between Organic Synthesis and Electrochemistry

   https://doi.org/10.1021/acs.accounts.9b00578  

   Jing, Q. ; Moeller, K. D. ( January 2020 , Accounts of chemical research)

   For many years, we looked at electrochemistry as a tool for exploring, developing, and implementing new synthetic methods for the construction of organic molecules. Those efforts examined electrochemical methods and mechanisms and then exploited them for synthetic gain. Chief among the tools utilized was the fact that in a constant current electrolysis the working potential at the electrodes automatically adjusted to the oxidation (anode) or reduction (cathode) potential of the substrates in solution. This allowed for a systematic examination of the radical cation intermediates that are involved in a host of oxidative cyclization reactions. The result has been a series of structure-activity studies that have led to far greater insight into the behavior of radical cation intermediates and in turn an expansion in our capabilities of using those intermediates to trigger interesting synthetic reactions. With that said, the relationship between synthetic organic chemistry and electrochemistry is not a "one-way" interaction. For example, we have been using modern synthetic methodology to construct complex addressable molecular surfaces on electroanalytical devices that in turn can be used to probe biological interactions between small molecules and biological receptors in "real-time" as the interactions happen. Synthetic chemistry can then be used to recover the molecules that give rise to positive signals so that they can be characterized. The result is an analytical method that both gives accurate data on the interactions and provides a unique level of quality control with respect to the molecules giving rise to that data. Synthetic organic chemistry is essential to this task because it is our ability to synthesize the surfaces that defines the nature of the biological problems that can be studied. But the relationship between the fields does not end there. Recently, we have begun to show that work to expand the scope of microelectrode arrays as bioanalytical devices is teaching us important lessons for preparative synthetic chemistry. These lessons come in two forms. First, the arrays have taught us about the on-site generation of chemical reagents, a lesson that is being used to expand the use of paired electrochemical strategies for synthesis. Second, the arrays have taught us that reagents can be generated and then confined to the surface of the electrode used for that generation. This has led to a new approach to taking advantage of molecular recognition events that occur on the surface of an electrode for controlling the selectivity of a preparative reaction. In short, the confinement strategy developed for the arrays is used to insure that the chemistry in a preparative electrolysis happens at the electrode surface and not in the bulk solution. This account details the interplay between synthetic chemistry and electrochemistry in our group through the years and highlights the opportunities that interplay has provided and will continue to provide in the future. 

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3. In vitro study of central nervous system foreign body response towards hydrogel particle modified planar substrate

   https://doi.org/10.1002/jbm.a.36180  

   Morin, Emily A. ; He, Wei ( August 2017 , Journal of Biomedical Materials Research Part A)

   Central nervous system (CNS) neural device functionality hinges on effective communication with surrounding neurons. This depends on both the permissiveness of the device material to promote neuron integration and the ability of the device to avoid a chronic inflammatory response. Previously our lab developed a method using surface adsorbed hydrogel particles (HPs) to promote neuron integration onto typically non‐neural‐permissive substrates. However, little information is known regarding CNS inflammatory cell type responses towards the modified HP surface.In vitroadhesion, proliferation, and activation studies were implemented using NIH 3T3, RAW 264.7, and A172 cell lines to model fibroblast, macrophages and activated microglia, and astrocytes, respectively. For all cell types, the HP modified substrates elicited cell adhesion and sustained cell metabolic activity during a 3‐day culture. RAW 264.7 cell activation was evaluated using a tumor necrosis factor‐alpha (TNF‐α) enzyme‐linked immunosorbent assay and scanning electron microscope (SEM) imaging. Quantified TNF‐α levels from the LbL/HP cells were greater than the control substrate, however, investigation with SEM suggested these cells’ morphology was different from a typical activated state. A172 cell activation was evaluated by fluorescent staining of glial fibrillary acidic protein (GFAP) and SEM imaging, which revealed similarly low GFAP levels on both bare and HP modified substrates. A172 cell morphology showed mainly an undifferentiated and non‐activated state. These results help lay the groundwork to design the HP system for futurein vitroandin vivoinvestigations to ultimately realize stable long‐term neural device communication. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3242–3250, 2017.

    

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4. Spatial variation in the intensity of interactions via heterospecific pollen transfer may contribute to local and global patterns of plant diversity

   https://doi.org/10.1093/aob/mcab082  

   Arceo-Gómez, Gerardo ( July 2021 , Annals of Botany)

   Studies that aim to understand the processes that generate and organize plant diversity in nature have a long history in ecology. Among these, the study of plant–plant interactions that take place indirectly via pollinator choice and floral visitation has been paramount. Current evidence, however, indicates that plants can interact more directly via heterospecific pollen (HP) transfer and that these interactions are ubiquitous and can have strong fitness effects. The intensity of HP interactions can also vary spatially, with important implications for floral evolution and community assembly.

   Interest in understanding the role of heterospecific pollen transfer in the diversification and organization of plant communities is rapidly rising. The existence of spatial variation in the intensity of species interactions and their role in shaping patterns of diversity is also well recognized. However, after 40 years of research, the importance of spatial variation in HP transfer intensity and effects remains poorly known, and thus we have ignored its potential in shaping patterns of diversity at local and global scales. Here, I develop a conceptual framework and summarize existing evidence for the ecological and evolutionary consequences of spatial variation in HP transfer interactions and outline future directions in this field.

   The drivers of variation in HP transfer discussed here illustrate the high potential for geographic variation in HP intensity and its effects, as well as in the evolutionary responses to HP receipt. So far, the study of pollinator-mediated plant–plant interactions has been almost entirely dominated by studies of pre-pollination interactions even though their outcomes can be influenced by plant–plant interactions that take place on the stigma. It is hence critical that we fully evaluate the consequences and context-dependency of HP transfer interactions in order to gain a more complete understanding of the role that plant–pollinator interactions play in generating and organizing plant biodiversity.

    

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5. Life Underground: Investigating Microbial Communities and Their Biomarkers in Mars‐Analog Lava Tubes at Craters of the Moon National Monument and Preserve

   https://doi.org/10.1029/2022JE007268  

   Weng, M. M. ; Zaikova, E. ; Millan, M. ; Williams, A. J. ; McAdam, A. C. ; Knudson, C. A. ; Fuqua, S. R. ; Wagner, N. Y. ; Craft, K. ; Kobs Nawotniak, S. ; et al ( November 2022 , Journal of Geophysical Research: Planets)

   Craters of the Moon National Monument and Preserve (CotM) is a strong terrestrial analog for lava tube formations on Mars. The commonality of its basalt composition to Martian lava tubes makes it especially useful for probing how interactions between water, rock, and life have developed over time, and what traces of these microbial communities may be detectable by current flight‐capable instrumentation. Our investigations found that secondary mineral deposits within these caves contain a range of underlying compositions that support diverse and active microbial communities. Examining the taxonomy, activity, and metabolic potential of these communities revealed largely heterotrophic life strategies supported by contributions from chemolithoautotrophs that facilitate key elemental cycles. Finally, traces of these microbial communities were detectable by flight‐capable pyrolysis and wet chemistry gas chromatography‐mass spectrometry methods comparable to those employed by the Sample Analysis at Mars (SAM) instrument aboard the Curiosity rover and the Mars Organic Molecule Analyzer (MOMA) on the upcoming Rosalind Franklin rover. Using a suite of methods for chemical derivatization of organic compounds is beneficial for resolving the greatest variety of biosignatures. Tetramethylammonium hydroxide (TMAH), for example, allowed for optimal resolution of long chain fatty acids. Taken together, these results have implications for the direction of mass spectrometry as a tool for biosignature detection on Mars, as well as informing the selection of sampling sites that could potentially host biosignatures.

    

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