ORCID Profile
0000-0003-1559-7463
Current Organisation
University of California Santa Barbara
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Publisher: Elsevier BV
Date: 12-1995
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 2011
Publisher: Wiley
Date: 18-09-2019
Publisher: Springer Science and Business Media LLC
Date: 09-10-2020
Publisher: Elsevier BV
Date: 10-2011
Publisher: American Geophysical Union (AGU)
Date: 06-2015
DOI: 10.1002/2015GC005779
Publisher: Elsevier BV
Date: 02-2022
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0SC05655C
Abstract: Phenazines were explored as novel low-midpoint potential molecules for wiring cyanobacteria to electrodes.
Publisher: Oxford University Press (OUP)
Date: 15-06-2014
Publisher: Elsevier BV
Date: 08-2023
Publisher: Elsevier BV
Date: 08-2000
Publisher: Elsevier BV
Date: 2008
Publisher: Elsevier BV
Date: 05-2001
Publisher: Wiley
Date: 09-2008
Publisher: Geological Society of America
Date: 23-06-2015
DOI: 10.1130/G36641.1
Publisher: Springer Science and Business Media LLC
Date: 10-1984
DOI: 10.1007/BF00381296
Publisher: Springer Science and Business Media LLC
Date: 07-03-2022
DOI: 10.1038/S41563-022-01205-5
Abstract: The rewiring of photosynthetic biomachineries to electrodes is a forward-looking semi-artificial route for sustainable bio-electricity and fuel generation. Currently, it is unclear how the electrode and biomaterial interface can be designed to meet the complex requirements for high biophotoelectrochemical performance. Here we developed an aerosol jet printing method for generating hierarchical electrode structures using indium tin oxide nanoparticles. We printed libraries of micropillar array electrodes varying in height and submicrometre surface features, and studied the energy/electron transfer processes across the bio-electrode interfaces. When wired to the cyanobacterium Synechocystis sp. PCC 6803, micropillar array electrodes with microbranches exhibited favourable biocatalyst loading, light utilization and electron flux output, ultimately almost doubling the photocurrent of state-of-the-art porous structures of the same height. When the micropillars' heights were increased to 600 µm, milestone mediated photocurrent densities of 245 µA cm
Publisher: Cold Spring Harbor Laboratory
Date: 04-2021
DOI: 10.1101/2021.04.01.437897
Abstract: Photosynthetic microorganisms can export electrons outside their cells, a phenomenon called exoelectrogenesis, which can be harnessed for solar energy conversion. However, the route electrons take from thylakoid membranes to the cell exterior is not understood. Electrochemistry is a powerful analytical technique for studying electron transfer pathways. Here, we show how photoelectrochemistry can be used to compare electron flux from cyanobacterial cells of different growth stages, species and with the outer layers systematically removed. We show that the periplasmic space contributes significantly to the photocurrent profile complexity of whole cells, indicating that it gates electron transfer in exoelectrogenesis. We found that although components of the type IV pili machinery do not have a role in exoelectrogenesis, they contribute significantly to cell-electrode adherence. This study establishes that analytical photoelectrochemistry and molecular microbiology provide a powerful combination to study exoelectrogenesis, enabling future studies to answer biological questions and advance solar energy conversion applications.
Publisher: Elsevier BV
Date: 09-2018
Publisher: Springer Science and Business Media LLC
Date: 05-2001
DOI: 10.1038/35075048
Publisher: Elsevier
Date: 2003
Publisher: Elsevier BV
Date: 08-2008
Publisher: Elsevier BV
Date: 06-2014
Publisher: Elsevier BV
Date: 02-2007
Publisher: Elsevier BV
Date: 09-2004
Publisher: Cambridge University Press (CUP)
Date: 09-07-2021
DOI: 10.33774/CHEMRXIV-2021-RRG7Q-V2
Abstract: The re-wiring of photosynthetic bio-machineries to electrodes is a forward-looking semi-artificial route for sustainable bio-electricity and fuel generation. Currently, it is unclear how the bio-material interface can be designed to meet the complex requirements for high bio-photoelectrochemical performance. Here, we developed an aerosol jet printing method for generating hierarchical electrode structures using indium tin oxide nanoparticles. We printed libraries of micropillar array electrodes varying in height and sub-micron surface features and studied the energy/electron transfer processes across the bio-electrode interfaces. When wired to the cyanobacterium Synechocysis sp. PCC 6803, micropillar array electrodes with micro-branches exhibited favourable biocatalyst loading, light utilisation and electron flux output, ultimately almost doubling the photocurrent of state-of-the-art porous structures of the same height. When the micropillars’ heights were increased from 50 to 600 µm, milestone mediated photocurrent densities of 245 µA cm–2 (the closest thus far to theoretical predictions) and external quantum efficiencies of up to 29% could be reached. This study demonstrates how bioenergy from photosynthesis could be more efficiently harnessed in the future and provide new tools for 3D electrode design.
Publisher: Elsevier BV
Date: 08-2016
Publisher: The Electrochemical Society
Date: 30-06-2019
Abstract: The photoelectrochemistry of natural photosynthetic machineries forms the foundations of many upcoming biotechnologies, whilst also providing valuable insights into the bioenergetics of the complex biological systems. Here, I will show recent developments in the integration of cyanobacterial components, including isolated photosystems, thylakoids and live biofilms into inverse opal mesoporous electrodes for photoelectrochemical studies. The systematic comparison of the different components, each being one step removed in metabolic complexity, allows the electron transfer processes at each level to be more effectively teased out. I will also showcase the coupling of photoelectrochemistry with additional biophysical techniques, including quartz crystal microbalance and dissipation, ATR-IR spectroscopy, fluorescence microscopy, and rotating ring disk electrode, for providing complemental insights into the bio-material interface.
Publisher: Elsevier BV
Date: 12-2007
Publisher: Elsevier BV
Date: 04-1998
Publisher: American Association for the Advancement of Science (AAAS)
Date: 22-01-2016
Abstract: The ghost of continental crust long eroded away may exist in certain element ratios found in Archean rocks. Tang et al. used Ni/Co and Cr/Zn ratios as a proxy for the magnesium oxide that long ago weathered away in Earth's oldest rocks. This allowed a reconstruction of rock composition, which appears to be very different from that of the crust today. The shift to contemporary crust composition occurred after the Archean era, suggesting the onset of plate tectonics. Science , this issue p. 372
Publisher: Elsevier BV
Date: 05-2002
Publisher: Wiley
Date: 09-12-2011
Publisher: Elsevier BV
Date: 06-2008
Publisher: American Chemical Society (ACS)
Date: 06-09-2018
DOI: 10.1021/JACS.8B08784
Publisher: American Association for the Advancement of Science (AAAS)
Date: 15-09-2000
DOI: 10.1126/SCIENCE.289.5486.1912
Abstract: Thermobarometric and Os isotopic data for peridotite xenoliths from late Miocene and younger lavas in the Sierra Nevada reveal that the lithospheric mantle is vertically stratified: the shallowest portions ( to 60 kilometers) are cold (670° to 740°C) and show evidence for heating and yield Proterozoic Os model ages, whereas the deeper portions (45 to 100 kilometers) yield Phanerozoic Os model ages and show evidence for extensive cooling from temperatures °C to 750°C. Because a variety of isotopic evidence suggests that the Sierran batholith formed on preexisting Proterozoic lithosphere, most of the original lithospheric mantle appears to have been removed before the late Miocene, leaving only a sliver of ancient mantle beneath the crust.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 06-2000
Publisher: Geological Society of London
Date: 1986
Publisher: Springer Science and Business Media LLC
Date: 13-05-2020
Publisher: Elsevier BV
Date: 06-2023
Publisher: Elsevier BV
Date: 2023
Publisher: Springer Science and Business Media LLC
Date: 17-07-2008
Publisher: Elsevier BV
Date: 07-2018
Publisher: Springer Science and Business Media LLC
Date: 22-03-2023
Publisher: Elsevier BV
Date: 08-2023
Publisher: Elsevier BV
Date: 08-2017
Publisher: American Geophysical Union (AGU)
Date: 08-2010
DOI: 10.1029/2010GC003063
Publisher: Elsevier BV
Date: 04-2008
Publisher: Springer Science and Business Media LLC
Date: 04-03-2019
Publisher: Elsevier BV
Date: 30-03-2003
Publisher: Cambridge University Press (CUP)
Date: 09-07-2021
DOI: 10.33774/CHEMRXIV-2021-RRG7Q
Abstract: The re-wiring of photosynthetic bio-machineries to electrodes is a forward-looking semi-artificial route for sustainable bio-electricity and fuel generation. Currently, it is unclear how the bio-material interface can be designed to meet the complex requirements for high bio-photoelectrochemical performance. Here, we developed an aerosol jet printing method for generating hierarchical electrode structures using indium tin oxide nanoparticles. We printed libraries of micropillar array electrodes varying in height and sub-micron surface features and studied the energy/electron transfer processes across the bio-electrode interfaces. When wired to the cyanobacterium Synechocysis sp. PCC 6803, micropillar array electrodes with micro-branches gave rise to substantially enhanced biocatalyst loading, light input, and electron flux output compared to state-of-the-art porous structures of the same height. Micropillar electrodes 600 µm in height reached milestone mediated photocurrent densities of 245 µA cm–2 (the closest thus far to theoretical predictions) and external quantum efficiencies of up to 29%. This study provides a blueprint for bio-hybrid electrode design, and tools for where electrode architecture is vital for performance.
Publisher: The Electrochemical Society
Date: 30-06-2019
Abstract: The emerging field of semi-artificial photosynthesis aims to combine the strengths of materials chemistry with biology to explore novel pathways for solar-to-chemical conversion. Here, I will describe the wiring of the water oxidation enzyme, photosystem II (PSII), to high surface area electrodes, thus allowing for electrons extracted from the first step of photosynthesis to be better harnessed for driving solar fuel conversion reactions and for interrogating enzyme functionality. I will focus on recently developed semi-artificial Z-schemes that rationally combines synthetic light harvesters with PSII to utilise more of the solar spectrum and achieve bias-free solar fuel production. These include tandem systems that utilise a p-Si based photocathode, and another that utilises a dye-sensitised PSII photoanode.
Publisher: Geological Society of America
Date: 2011
Publisher: American Association for the Advancement of Science (AAAS)
Date: 06-05-2022
Abstract: Synthetic biology research and its industrial applications rely on deterministic spatiotemporal control of gene expression. Recently, electrochemical control of gene expression has been demonstrated in electrogenetic systems (redox-responsive promoters used alongside redox inducers and electrodes), allowing for the direct integration of electronics with biological processes. However, the use of electrogenetic systems is limited by poor activity, tunability, and standardization. In this work, we developed a strong, unidirectional, redox-responsive promoter before deriving a mutant promoter library with a spectrum of strengths. We constructed genetic circuits with these parts and demonstrated their activation by multiple classes of redox molecules. Last, we demonstrated electrochemical activation of gene expression under aerobic conditions using a novel, modular bioelectrochemical device. These genetic and electrochemical tools facilitate the design and improve the performance of electrogenetic systems. Furthermore, the genetic design strategies used can be applied to other redox-responsive promoters to further expand the available tools for electrogenetics.
Publisher: Springer Science and Business Media LLC
Date: 21-12-2019
Publisher: Springer Science and Business Media LLC
Date: 12-2004
DOI: 10.1038/NATURE03162
Abstract: Foundering of mafic lower continental crust into underlying convecting mantle has been proposed as one means to explain the unusually evolved chemical composition of Earth's continental crust, yet direct evidence of this process has been scarce. Here we report that Late Jurassic high-magnesium andesites, dacites and adakites (siliceous lavas with high strontium and low heavy-rare-earth element and yttrium contents) from the North China craton have chemical and petrographic features consistent with their origin as partial melts of eclogite that subsequently interacted with mantle peridotite. Similar features observed in adakites and some Archaean sodium-rich granitoids of the tonalite-trondhjemite-granodiorite series have been interpreted to result from interaction of slab melts with the mantle wedge. Unlike their arc-related counterparts, however, the Chinese magmas carry inherited Archaean zircons and have neodymium and strontium isotopic compositions overlapping those of eclogite xenoliths derived from the lower crust of the North China craton. Such features cannot be produced by crustal assimilation of slab melts, given the high Mg#, nickel and chromium contents of the lavas. We infer that the Chinese lavas derive from ancient mafic lower crust that foundered into the convecting mantle and subsequently melted and interacted with peridotite. We suggest that lower crustal foundering occurred within the North China craton during the Late Jurassic, and thus provides constraints on the timing of lithosphere removal beneath the North China craton.
Publisher: Elsevier BV
Date: 06-2022
Publisher: Elsevier BV
Date: 10-2018
Publisher: Wiley
Date: 17-07-2018
Publisher: Elsevier BV
Date: 08-2010
Publisher: Elsevier BV
Date: 04-2000
Publisher: American Geophysical Union (AGU)
Date: 07-2018
DOI: 10.1029/2018GC007534
Abstract: Some seismic models derived from tomographic studies indicate elevated shear‐wave velocities (≥4.7 km/s) around 120–150 km depth in cratonic lithospheric mantle. These velocities are higher than those of cratonic peridotites, even assuming a cold cratonic geotherm (i.e., 35 mW/m 2 surface heat flux) and accounting for compositional heterogeneity in cratonic peridotite xenoliths and the effects of anelasticity. We reviewed various geophysical and petrologic constraints on the nature of cratonic roots (seismic velocities, lithology/mineralogy, electrical conductivity, and gravity) and explored a range of permissible rock and mineral assemblages that can explain the high seismic velocities. These constraints suggest that diamond and eclogite are the most likely high‐ V s candidates to explain the observed velocities, but matching the high shear‐wave velocities requires either a large proportion of eclogite ( vol.%) or the presence of up to 3 vol.% diamond, with the exact values depending on peridotite and eclogite compositions and the geotherm. Both of these estimates are higher than predicted by observations made on natural s les from kimberlites. However, a combination of ≤20 vol.% eclogite and ~2 vol.% diamond may account for high shear‐wave velocities, in proportions consistent with multiple geophysical observables, data from natural s les, and within mass balance constraints for global carbon. Our results further show that cratonic thermal structure need not be significantly cooler than determined from xenolith thermobarometry.
Publisher: Geological Society of America
Date: 20-04-2023
DOI: 10.1130/B36836.1
Abstract: Petrologic and geochronologic data for metapelitic lower crustal xenoliths from New Mexico (USA) and Chihuahua (Mexico) states provide evidence for both a magmatic and collisional component to the enigmatic Mesoproterozoic Picuris orogeny. These garnet-sillimanite-bearing metapelites are found within the southern Rio Grande rift at Kilbourne Hole and Potrillo Maar in southern New Mexico and northern Chihuahua. Geothermobarometry and rutile with Quaternary U-Pb dates indicate equilibration in the local lower crust, which is actively undergoing ultra-high temperature (UHT) metamorphism (Cipar et al., 2020). The s les contain older detrital zircons dating back to the Paleoproterozoic, marking their deposition at the surface. Coupled zircon U-Pb dates and trace-element ratios (e.g., Gd/Yb) show a clear transition from oscillatory-zoned, low-Gd/Yb detrital magmatic zircon to featureless, high-Gd/Yb metamorphic zircon between 1500 and 1400 Ma, marking the transition from subduction to collision during this period. Metamorphic zircon and monazite grew in two major intervals. The first, between ca. 1450 and 1350 Ma, documents the journey of the sediments to depth within the orogen and provides evidence of extended Mesoproterozoic metamorphism in the region. The second corresponds with UHT metamorphism that commenced at ca. 32 Ma and is associated with the Rio Grande rift. Whereas nearly all garnets are homogeneous in both major and trace elements, a single garnet from one s le has a core defined by abundant quartz and acicular sillimanite inclusions. The core and rim of this garnet is homogeneous in major and most trace elements, but the rim is enriched in the slowest diffusing elements, Zr and Hf, which likely indicates rim growth at higher temperatures. We interpret the garnet core to have grown at the time of emplacement of the sediments into the lower crust. Because this occurred in the sillimanite stability field and because the metamorphic zircon and monazite all have negative Eu anomalies, indicating their equilibration with feldspar (stable at depths of & km), we conclude that the sediments were not emplaced via subduction and/or relamination of forearc sediments, but were instead metamorphosed under warmer, shallower conditions in an orogenic setting. Collectively, the data point to a collisional orogen during the inferred timing of the Picuris orogeny. These s les may therefore define the location of the Picuris suture zone, a key feature of this orogenic event.
Publisher: Mineralogical Society of America
Date: 2017
Publisher: Proceedings of the National Academy of Sciences
Date: 19-12-2011
Abstract: Chemical weathering, as well as physical erosion, changes the composition and shapes the surface of the continental crust. However, the amount of continental material that has been lost over Earth’s history due to chemical weathering is poorly constrained. Using a mass balance model for lithium inputs and outputs from the continental crust, we find that the mass of continental crust that has been lost due to chemical weathering is at least 15% of the original mass of the juvenile continental crust, and may be as high as 60%, with a best estimate of approximately 45%. Our results suggest that chemical weathering and subsequent subduction of soluble elements have major impacts on both the mass and the compositional evolution of the continental crust.
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 09-2008
Publisher: Elsevier BV
Date: 09-2006
Publisher: Mineralogical Society of America
Date: 08-2020
Publisher: Elsevier BV
Date: 05-2015
Publisher: Elsevier BV
Date: 12-2009
Publisher: Springer Science and Business Media LLC
Date: 30-01-2009
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 07-2011
Publisher: Elsevier BV
Date: 11-2004
Publisher: Elsevier BV
Date: 10-2004
Publisher: Elsevier BV
Date: 12-2010
Publisher: American Geophysical Union (AGU)
Date: 09-2013
DOI: 10.1002/GGGE.20238
Publisher: Elsevier BV
Date: 03-2016
Publisher: Elsevier BV
Date: 07-2023
Publisher: Springer Science and Business Media LLC
Date: 05-1998
DOI: 10.1038/29966
Publisher: Springer Science and Business Media LLC
Date: 22-08-2023
Publisher: IOP Publishing
Date: 22-06-2022
Abstract: Renewable fuel generation is essential for a low carbon footprint economy. Thus, over the last five decades, a significant effort has been dedicated towards increasing the performance of solar fuels generating devices. Specifically, the solar to hydrogen efficiency of photoelectrochemical cells has progressed steadily towards its fundamental limit, and the faradaic efficiency towards valuable products in CO 2 reduction systems has increased dramatically. However, there are still numerous scientific and engineering challenges that must be overcame in order to turn solar fuels into a viable technology. At the electrode and device level, the conversion efficiency, stability and products selectivity must be increased significantly. Meanwhile, these performance metrics must be maintained when scaling up devices and systems while maintaining an acceptable cost and carbon footprint. This roadmap surveys different aspects of this endeavor: system benchmarking, device scaling, various approaches for photoelectrodes design, materials discovery, and catalysis. Each of the sections in the roadmap focuses on a single topic, discussing the state of the art, the key challenges and advancements required to meet them. The roadmap can be used as a guide for researchers and funding agencies highlighting the most pressing needs of the field.
Publisher: Elsevier BV
Date: 08-2022
Publisher: American Chemical Society (ACS)
Date: 09-07-2021
DOI: 10.26434/CHEMRXIV-2021-RRG7Q-V2
Abstract: The re-wiring of photosynthetic bio-machineries to electrodes is a forward-looking semi-artificial route for sustainable bio-electricity and fuel generation. Currently, it is unclear how the bio-material interface can be designed to meet the complex requirements for high bio-photoelectrochemical performance. Here, we developed an aerosol jet printing method for generating hierarchical electrode structures using indium tin oxide nanoparticles. We printed libraries of micropillar array electrodes varying in height and sub-micron surface features and studied the energy/electron transfer processes across the bio-electrode interfaces. When wired to the cyanobacterium Synechocysis sp. PCC 6803, micropillar array electrodes with micro-branches exhibited favourable biocatalyst loading, light utilisation and electron flux output, ultimately almost doubling the photocurrent of state-of-the-art porous structures of the same height. When the micropillars’ heights were increased from 50 to 600 µm, milestone mediated photocurrent densities of 245 µA cm–2 (the closest thus far to theoretical predictions) and external quantum efficiencies of up to 29% could be reached. This study demonstrates how bioenergy from photosynthesis could be more efficiently harnessed in the future and provide new tools for 3D electrode design.
Publisher: Springer Science and Business Media LLC
Date: 03-09-2018
Publisher: Elsevier BV
Date: 12-2003
Publisher: Cold Spring Harbor Laboratory
Date: 11-09-2021
DOI: 10.1101/2021.09.10.459750
Abstract: Synthetic biology research and its industrial applications rely on the deterministic spatiotemporal control of gene expression. Recently, electrochemical control of gene expression has been demonstrated in electrogenetic systems (redox-responsive promoters used alongside redox inducers and an electrode), allowing for the direct integration of electronics with complex biological processes for a variety of new applications. However, the use of electrogenetic systems is limited by poor activity, tunability and standardisation. Here, we have developed a variety of genetic and electrochemical tools that facilitate the design and vastly improve the performance of electrogenetic systems. We developed a strong, unidirectional, redox-responsive promoter before deriving a mutant promoter library with a spectrum of strengths. We then constructed genetic circuits with these parts and demonstrated their activation by multiple classes of redox molecules. Finally, we demonstrated electrochemical activation of gene expression in aerobic conditions utilising a novel, modular bioelectrochemical device. This toolset provides researchers with all the elements needed to design and build optimised electrogenetic systems for specific applications.
Publisher: Oxford University Press (OUP)
Date: 03-09-2009
Publisher: Elsevier BV
Date: 11-2004
Publisher: American Chemical Society (ACS)
Date: 05-2019
Publisher: Elsevier
Date: 2003
Publisher: Elsevier BV
Date: 11-2014
Publisher: American Geophysical Union (AGU)
Date: 06-2013
DOI: 10.1002/GGGE.20129
Publisher: Elsevier BV
Date: 06-2020
Publisher: Springer Science and Business Media LLC
Date: 21-02-2020
Publisher: European Association of Geochemistry
Date: 06-2022
Publisher: Elsevier BV
Date: 08-2013
Publisher: Elsevier BV
Date: 2011
Publisher: Elsevier BV
Date: 10-2016
Publisher: Elsevier BV
Date: 15-04-2007
Publisher: American Association for the Advancement of Science (AAAS)
Date: 14-01-2000
DOI: 10.1126/SCIENCE.287.5451.278
Abstract: A mass imbalance exists in Earth for Nb, Ta, and possibly Ti: continental crust and depleted mantle both have subchondritic Nb/Ta, Nb/La, and Ti/Zr, which requires the existence of an additional reservoir with superchondritic ratios, such as refractory eclogite produced by slab melting. Trace element compositions of minerals in xenolithic eclogites derived from cratonic lithospheric mantle show that rutile dominates the budget of Nb and Ta in the eclogites and imparts a superchondritic Nb/Ta, Nb/La, and Ti/Zr to the whole rocks. About 1 to 6 percent by weight of eclogite is required to solve the mass imbalance in the silicate Earth, and this reservoir must have an Nb concentration ≥ 2 parts per million, Nb/La ≥ 1.2, and Nb/Ta between 19 and 37—values that overlap those of the xenolithic eclogites. As the mass of eclogite in the continental lithosphere is significantly lower than this, much of this material may reside in the lower mantle, perhaps as deep as the core-mantle boundary.
Publisher: Proceedings of the National Academy of Sciences
Date: 09-03-2023
Abstract: The transition from mafic to felsic upper continental crust (UCC) is crucial to habitability of Earth, and may be related to the onset of plate tectonics. Thus, defining when this crustal transition occurred has great significance for the evolution of Earth and its inhabitants. We demonstrate that V isotope ratios (reported as δ 51 V) provide insights into this transition because they correlate positively with SiO 2 and negatively with MgO contents during igneous differentiation in both subduction zones and intraplate settings. Because δ 51 V is not affected by chemical weathering and fluid–rock interactions, δ 51 V of the fine-grained matrix of Archean to Paleozoic (3 to 0.3 Ga) glacial diamictite composites, which s le the UCC at the time of glaciation, reflect the chemical composition of the UCC through time. The δ 51 V values of glacial diamictites systematically increase with time, indicating a dominantly mafic UCC at ~3 Ga the UCC was dominated by felsic rocks only after 3 Ga, coinciding with widespread continental emergence and many independent estimates for the onset of plate tectonics.
Publisher: Elsevier BV
Date: 11-2009
Publisher: Elsevier BV
Date: 11-2010
Publisher: Elsevier BV
Date: 04-1999
Publisher: Geological Society of America
Date: 1991
Publisher: Elsevier BV
Date: 09-2017
Publisher: IOP Publishing
Date: 30-07-2012
Publisher: Geological Society of America
Date: 23-10-2015
DOI: 10.1130/G37259.1
Publisher: Mineralogical Society of America
Date: 10-2006
DOI: 10.2138/AM.2006.2083
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 10-2015
Publisher: Wiley
Date: 16-10-2019
Publisher: Elsevier BV
Date: 12-2019
Publisher: Routledge
Date: 25-03-2013
Publisher: Elsevier BV
Date: 04-2007
Publisher: American Geophysical Union (AGU)
Date: 10-2022
DOI: 10.1029/2022GC010497
Abstract: Coupled U‐Pb and trace‐element analyses of accessory phases in crustal xenoliths from the Late Devonian Udachnaya kimberlite (Siberian craton, Russia) are used to constrain Moho temperature and crustal heat production at the time of kimberlite eruption. Rutile and apatite in lower‐crustal garnet granulites record U‐Pb dates that extend from 1.8 Ga to 360 Ma (timing of kimberlite eruption). This contrasts with upper‐crustal tonalites and hibolites that contain solely Paleoproterozoic apatite. Depth profiling of rutile from the lower‐crustal xenoliths show that U‐Pb dates increase gradually from rim to core over μm‐scale distances, with slower‐diffusing elements (e.g., Al) increasing in concentration across similar length‐scales. The U‐Pb and trace element gradients in rutile are incompatible with partial Pb loss during slow cooling, but are consistent with neocrystallization and re‐heating of the lower crust for Myr prior to eruption. Because Paleoproterozoic rutile and apatite dates are preserved, we infer that long‐term ambient lower‐crustal temperatures before this thermal perturbation were cooler than the Pb closure temperature of rutile and probably apatite ( °C). The lower‐crustal temperature bounds from these data are consistent with pressure‐temperature arrays of Udachnaya peridotite xenoliths that suggest relatively cool geothermal gradients, signifying that the mantle xenoliths accurately capture the thermal state of the lithosphere prior to eruption. Combined, the xenolith data imply low crustal heat production for the Siberian craton (∼0.3 μW/m 3 ). Nevertheless, such values produce surface heat flow values of 20–40 mW/m 2 , higher than measured around Udachnaya (average 19 mW/m 2 ), suggesting that the surface heat flow measurements are inaccurate.
Publisher: Wiley
Date: 02-02-2015
Publisher: Springer International Publishing
Date: 2017
Publisher: Elsevier BV
Date: 03-2020
Publisher: American Chemical Society (ACS)
Date: 19-12-2018
DOI: 10.1021/ACS.BIOCONJCHEM.8B00792
Abstract: A series of peptides based on the prostate-specific antigen (PSA)-specific sequence histidine-serine-serine-lysine-leucine-glutamine were functionalized with an anthraquinone fluorophore at the C-terminal residue side chain using the copper(I)-catalyzed azide-alkyne cycloaddition reaction. The effect of incorporating a negatively charged N-terminal tetra-glutamic acid group into the substrate and the effect of masking the negatively charged C-terminal carboxylic acid functionality of the substrate were investigated using confocal fluorescence microscopy in two cell lines, DLD-1 and LnCaP. The addition of a tetra-glutamic acid group to the N-terminus of the intact sequence was shown to reduce cellular uptake of the intact substrate prior to activation by PSA. In contrast, masking the C-terminal carboxylic acid group of the substrate as a methyl ester was shown to improve cellular uptake of the peptide fragment after activation by PSA. The synthesized C-terminal methyl ester substrates with the anthraquinone attached to the side chain were confirmed to be cleaved by PSA in LC-MS analysis, and the cytotoxicity of the substrates was shown to increase in the presence of PSA, consistent with cleavage and uptake of the C-terminal fragment. The results indicate that C- and N-terminal functionalization of peptide substrates targeting PSA can be used to modulate the cellular uptake of peptides before and after enzymatic activation, which may thus be an important consideration in the design of tumor-activated prodrugs.
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 04-2005
Publisher: Elsevier BV
Date: 2009
Publisher: Elsevier BV
Date: 11-2002
Publisher: American Chemical Society (ACS)
Date: 28-01-2019
Publisher: Elsevier BV
Date: 12-2014
Publisher: Elsevier BV
Date: 09-2015
Publisher: Elsevier BV
Date: 2007
Publisher: Elsevier BV
Date: 07-2001
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-09-2023
Publisher: Elsevier BV
Date: 11-2012
Publisher: American Chemical Society (ACS)
Date: 09-07-2021
DOI: 10.26434/CHEMRXIV-2021-RRG7Q
Abstract: The re-wiring of photosynthetic bio-machineries to electrodes is a forward-looking semi-artificial route for sustainable bio-electricity and fuel generation. Currently, it is unclear how the bio-material interface can be designed to meet the complex requirements for high bio-photoelectrochemical performance. Here, we developed an aerosol jet printing method for generating hierarchical electrode structures using indium tin oxide nanoparticles. We printed libraries of micropillar array electrodes varying in height and sub-micron surface features and studied the energy/electron transfer processes across the bio-electrode interfaces. When wired to the cyanobacterium Synechocysis sp. PCC 6803, micropillar array electrodes with micro-branches gave rise to substantially enhanced biocatalyst loading, light input, and electron flux output compared to state-of-the-art porous structures of the same height. Micropillar electrodes 600 µm in height reached milestone mediated photocurrent densities of 245 µA cm–2 (the closest thus far to theoretical predictions) and external quantum efficiencies of up to 29%. This study provides a blueprint for bio-hybrid electrode design, and tools for where electrode architecture is vital for performance.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 12-2002
Publisher: Informa UK Limited
Date: 07-2005
DOI: 10.1080/14763140508522866
Abstract: The aim of this study was to determine whether a constructivist approach, in particular a visit to a zoo, could be effective in consolidating mechanical concepts and applying those concepts to coaching and teaching. Ten students in their final year of their Bachelor of Physical Education at the University of Edinburgh participated in a visit to Edinburgh Zoo. During the visit students completed a worksheet of questions and engaged interactively in discussing how various animals are adapted mechanically to survive in their environments. Immediately after the visit they completed a questionnaire with four sections. The first section assessed whether they could apply the mechanical concepts discussed during the visit to human sports performance. The second canvassed their opinions on whether the visit was effective in reinforcing mechanical concepts, in developing 'lateral thinking' about mechanical concepts, and in improving their ability to apply mechanical concepts to coaching and teaching. The third canvassed their opinions on whether the visit would be effective for senior high school Physical Education and Sports Science students for developing mechanical concepts and applying them to coaching. The fourth section canvassed their opinions on when the visit should be conducted for Physical Education and Sports Science students in universities and in senior high schools. The results indicated that the visit was effective in reinforcing mechanical concepts and in applying them laterally to improve understanding of human sports performance. Participants believed that the visit would also be effective for senior high school students. All participants believed that the visit would be most beneficial after at least one course in biomechanics that covers the basic biomechanical principles.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 05-2009
Publisher: Elsevier BV
Date: 03-2006
Publisher: Springer Science and Business Media LLC
Date: 10-2018
DOI: 10.1038/S41565-018-0251-7
Abstract: Semi-artificial photosynthetic systems aim to overcome the limitations of natural and artificial photosynthesis while providing an opportunity to investigate their respective functionality. The progress and studies of these hybrid systems is the focus of this forward-looking perspective. In this Review, we discuss how enzymes have been interfaced with synthetic materials and employed for semi-artificial fuel production. In parallel, we examine how more complex living cellular systems can be recruited for in vivo fuel and chemical production in an approach where inorganic nanostructures are hybridized with photosynthetic and non-photosynthetic microorganisms. Side-by-side comparisons reveal strengths and limitations of enzyme- and microorganism-based hybrid systems, and how lessons extracted from studying enzyme hybrids can be applied to investigations of microorganism-hybrid devices. We conclude by putting semi-artificial photosynthesis in the context of its own ambitions and discuss how it can help address the grand challenges facing artificial systems for the efficient generation of solar fuels and chemicals.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Wiley
Date: 09-2021
DOI: 10.1111/MAPS.13733
Publisher: Elsevier BV
Date: 08-2023
Publisher: Wiley
Date: 17-04-2016
DOI: 10.1111/MAPS.12643
Location: United States of America
Start Date: 2007
End Date: 2010
Funder: National Science Foundation - Directorate for Geosciences
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Funder: National Science Foundation - Directorate for Geosciences
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Funder: Directorate for Geosciences
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Funder: Council for International Exchange of Scholars
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Funder: Directorate for Geosciences
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Funder: Directorate for Geosciences
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Funder: Directorate for Education & Human Resources
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Funder: Directorate for Geosciences
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Funder: Directorate for Geosciences
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Funder: Directorate for Geosciences
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Funder: Directorate for Geosciences
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