Publications

Exploration of the bio-analogous asymmetric C–C coupling mechanism in tandem CO2 electroreduction

CCDC 2034513: Experimental Crystal Structure Determination

<i>Operando</i> Electrochemical Liquid-Cell 4D-STEM Studies of Dynamic Evolution of Cu Nanocatalysts for CO2 Reduction

Journal Article Operando Electrochemical Liquid-Cell 4D-STEM Studies of Dynamic Evolution of Cu Nanocatalysts for CO2 Reduction Get access Yao Yang, Yao Yang Department of Chemistry, Miller Institute, UC Berkeley, Berkeley, CA, United StatesSchool of Applied and Engineering Physics, Cornell University, Ithaca, NY, United States Search for other works by this author on: Oxford Academic Google Scholar Yu-Tsun Shao, Yu-Tsun Shao Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, United StatesDepartment of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, United States Search for other works by this author on: Oxford Academic Google Scholar Héctor D Abruña, Héctor D Abruña Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, United States Search for other works by this author on: Oxford Academic Google Scholar David A Muller, David A Muller Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, United States Search for other works by this author on: Oxford Academic Google Scholar Peidong Yang Peidong Yang Department of Chemistry, Miller Institute, UC Berkeley, Berkeley, CA, United States Corresponding author: p_yang@berkeley.edu Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 29, Issue Supplement_1, 1 August 2023, Pages 1300–1301, https://doi.org/10.1093/micmic/ozad067.665 Published: 22 July 2023

Development of a General Aza-Cope Reaction Trigger Applied to Fluorescence Imaging of Formaldehyde in Living Cells

Formaldehyde (FA) is a reactive signaling molecule that is continuously produced through a number of central biological pathways spanning epigenetics to one-carbon metabolism. On the other hand, aberrant, elevated levels of FA are implicated in disease states ranging from asthma to neurodegenerative disorders. In this context, fluorescence-based probes for FA imaging are emerging as potentially powerful chemical tools to help disentangle the complexities of FA homeostasis and its physiological and pathological contributions. Currently available FA indicators require direct modification of the fluorophore backbone through complex synthetic considerations to enable FA detection, often limiting the generalization of designs to other fluorophore classes. To address this challenge, we now present the rational, iterative development of a general reaction-based trigger utilizing 2-aza-Cope reactivity for selective and sensitive detection of FA in living systems. Specifically, we developed a homoallylamine functionality that can undergo a subsequent self-immolative β-elimination, creating a FA-responsive trigger that is capable of masking a phenol on a fluorophore or any other potential chemical scaffold for related imaging and/or therapeutic applications. We demonstrate the utility of this trigger by creating a series of fluorescent probes for FA with excitation and emission wavelengths that span the UV to visible spectral regions through caging of a variety of dye units. In particular, Formaldehyde Probe 573 (FAP573), based on a resorufin scaffold, is the most red-shifted and FA sensitive in this series in terms of signal-to-noise responses and enables identification of alcohol dehydrogenase 5 (ADH5) as an enzyme that regulates FA metabolism in living cells. The results provide a starting point for the broader use of 2-aza-Cope reactivity for probing and manipulating FA biology.

CCDC 1899148: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Adsorbate-adsorbate interactions and the ordering of organic monolayers on metal surfaces

Faculty Opinions recommendation of Plant root exudates increase methane emissions through direct and indirect pathways.

Abrasive Wear Behavior of Heat‐Treated ABC‐Silicon Carbide

Hot‐pressed silicon carbide, containing aluminum, boron, and carbon additives (ABC‐SiC), was subjected to three‐body and two‐body wear testing using diamond abrasives over a range of sizes. In general, the wear resistance of ABC‐SiC, with suitable heat treatment, was superior to that of commercial SiC. When the fine‐scale (3 μm) diamond abrasives were used, it was found that thermal annealing at 1300°C increased the resistance to three‐body wear by a factor of almost three, and two‐body wear by a factor of almost two, compared with as‐hot‐pressed samples. Higher annealing temperatures, however, led to a decline in wear resistance from its highest value. Similar behavior was seen for 1300°C‐annealed samples subjected to 15 μm diamond abrasive, although higher‐temperature annealing at 1500°–1600°C enhanced the wear resistance again. When coarse abrasives (72 μm) were used, the wear resistance progressively increased with increased annealing temperature from ∼1000° to 1600°C. Corresponding transmission and scanning electron microscopy studies indicated that, whereas transgranular, conchoidal cracking was dominant in the mild abrasive wear with fine‐scale (3 μm) abrasives, intergranular cracking and subsequent grain pullout was far more predominant in the more severe abrasive wear with coarse abrasives. Because the hardness and indentation toughness were barely altered during thermal treatment, the observed wear behavior was attributed mainly to the thermally induced microstructural changes, including the crystallization of glassy grain‐boundary films, the possible strengthening of the boundaries due to the enhancement of the aluminum, and the formation of aluminum‐rich, coherent nanoscale precipitates in the matrix grains above 1300°C.

Subcanopy Solar Radiation model: Predicting solar radiation across a heavily vegetated landscape using LiDAR and GIS solar radiation models

The Role of Electronic Properties in the Electrochemical Behavior of Intercalation Compounds From a First Principles Vantage Point

Geochronological Constraints on the Evolution and Petrogenesis of the Malwa Plateau Subprovince of the Deccan Traps

Abstract The eruptive history of the Malwa Plateau Subprovince of the Deccan Traps is addressed by dating 21 lavas spanning the exposed stratigraphic extent, using the 40 Ar/ 39 Ar method applied to plagioclase separates. Major, minor, and trace element geochemistry was determined for each of the dated lavas and four additional ones. Dating results indicate that the eruptions began prior to 66.8 Ma, at least 400 ka before the oldest known lava in the more extensively studied Western Ghats, representative of the main Deccan province, to the south. Eruption rates peaked from 66.4 to 66.3 Ma and then diminished until 65.6 Ma. The peak in eruption rates coincides with the well‐documented Late Maastrichtian Warming event. Malwa lavas show some major and trace element affinities with geochemically defined lava flow formations of the Western Ghats, but are generally out of the stratigraphic sequence manifest in the Western Ghats. The distinct geochemical evolution of Malwa Plateau lavas compared with those of the Western Ghats is at least in part a consequence of differences in crustal composition between the two subprovinces. Modeling of REE concentration patterns of Malwa lavas suggests that they were derived by slightly lower degrees of partial melting, at lower mantle temperatures and depths, than those in the Western Ghats. The Malwa Plateau thus appears to record an earlier, cooler stage of the Deccan plume's evolution and continued to erupt through a large part of the lifetime of the main Deccan province.

CCDC 2210566: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Long-Term Profile Variability of Double-Peaked Emitters

Monitoring the Biodegradation of Dendritic Near-Infrared Nanoprobes by <i>in Vivo</i> Fluorescence Imaging

Synthetic polymers and dendrimers have been widely used by the medical community to overcome biological barriers and enhance in vivo biomedical applications. Despite the widespread use of biomaterials it has been generally extremely difficult to monitor noninvasively their fate in vivo. Here we report multilayered nanoprobes, consisting of a near-infrared core, nanoencapsulated in a biodegradable dendrimer, and surrounded by a shell of polyethylene oxide. Covalent encapsulation of the near-infrared fluorophores in the dendritic scaffold conferred enhanced stability to the nanoprobe with added resistance to enzymatic oxidation and prolonged blood residence time. Insight into the time course of biodegradation of the dendritic aliphatic polyester nanoprobe was gained using noninvasive whole body in vivo fluorescence lifetime imaging. As the dendritic shell biodegrades the NIR probe becomes exposed, enabling monitoring of fluorescence lifetime changes in vivo.

Photosynthetic responses to temperature across leaf–canopy–ecosystem scales: a 15-year study in a Californian oak-grass savanna

Low growth hormone response to growth hormone–releasing hormone in child depression

The Electrochemical Impedance of Porous Nickel Electrodes in Alkaline Media: I . Experimental Studies

Electrochemical impedance and capacity data for porous nickel electrodes in 31% at ambient temperature were obtained as a function of cycle number. The isopotential impedance magnitude at any given frequency, |Z|, decreased and the capacity of two types of sintered porous nickel electrodes increased during the first few hundred cycles, before becoming constant. The electrodes were cycled for about 1400 cycles under two different cycling regimes simulating low earth orbit operation and stress charging/discharging. Electrochemical impedance data were also obtained for a planar nickel electrode in 31% as a function of applied dc potential to provide fundamental data for simulating the and phases within the pores. These data are used in Part II of this series to model porous nickel electrodes in terms of nonuniform transmission lines.

CCDC 1424238: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.