| 1. |
- Parts, Leopold, et al.
(author)
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Extent, causes, and consequences of small RNA expression variation in human adipose tissue.
- 2012
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In: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 8:5
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Journal article (peer-reviewed)abstract
- Small RNAs are functional molecules that modulate mRNA transcripts and have been implicated in the aetiology of several common diseases. However, little is known about the extent of their variability within the human population. Here, we characterise the extent, causes, and effects of naturally occurring variation in expression and sequence of small RNAs from adipose tissue in relation to genotype, gene expression, and metabolic traits in the MuTHER reference cohort. We profiled the expression of 15 to 30 base pair RNA molecules in subcutaneous adipose tissue from 131 individuals using high-throughput sequencing, and quantified levels of 591 microRNAs and small nucleolar RNAs. We identified three genetic variants and three RNA editing events. Highly expressed small RNAs are more conserved within mammals than average, as are those with highly variable expression. We identified 14 genetic loci significantly associated with nearby small RNA expression levels, seven of which also regulate an mRNA transcript level in the same region. In addition, these loci are enriched for variants significant in genome-wide association studies for body mass index. Contrary to expectation, we found no evidence for negative correlation between expression level of a microRNA and its target mRNAs. Trunk fat mass, body mass index, and fasting insulin were associated with more than twenty small RNA expression levels each, while fasting glucose had no significant associations. This study highlights the similar genetic complexity and shared genetic control of small RNA and mRNA transcripts, and gives a quantitative picture of small RNA expression variation in the human population.
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| 2. |
- Enright, Michael J., et al.
(author)
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Role of Atomic Structure on Exciton Dynamics and Photoluminescence in NIR Emissive InAs/InP/ZnSe Quantum Dots
- 2022
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In: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 126:17, s. 7576-7587
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Journal article (peer-reviewed)abstract
- The development of bright, near-infrared-emissive quantum dots (QDs) is a necessary requirement for the realization of important new classes of technology. Specifically, there exist significant needs for brighter, heavy metal-free, near-infrared (NIR) QDs for applications with high radiative efficiency that span diverse applications, including down-conversion emitters for high-performance luminescent solar concentrators. We use a combination of theoretical and experimental approaches to synthesize bright, NIR luminescent InAs/InP/ZnSe QDs and elucidate fundamental material attributes that remain obstacles for development of near-unity NIR QD luminophores. First, using Monte Carlo ray tracing, we identify the atomic and electronic structural attributes of InAs core/shell, NIR emitters, whose luminescence properties can be tailored by synthetic design to match most beneficially those of high-performance, single-band-gap photovoltaic devices based on important semiconductor materials, such Si or GaAs. Second, we synthesize InAs/InP/ZnSe QDs based on the optical attributes found to maximize LSC performance and develop methods to improve the emissive qualities of NIR emitters with large, tunable Stokes ratios, narrow emission linewidths, and high luminescence quantum yields (here reaching 60 +/- 2%). Third, we employ atomistic electronic structure calculations to explore charge carrier behavior at the nanoscale affected by interfacial atomic structures and find that significant exciton occupation of the InP shell occurs in most cases despite the InAs/InP type I bulk band alignment. Furthermore, the density of the valence band maximum state extends anisotropically through the (111) crystal planes to the terminal InP surfaces/interfaces, indicating that surface defects, such as unpassivated phosphorus dangling bonds, located on the (111) facets play an outsized role in disrupting the valence band maximum and quenching photoluminescence.
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| 3. |
- Li, Yuanyuan, et al.
(author)
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Dynamic structure of active sites in ceria-supported Pt catalysts for the water gas shift reaction
- 2021
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In: Nature Communications. - : Springer Nature. - 2041-1723. ; 12:1
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Journal article (peer-reviewed)abstract
- Oxide-supported noble metal catalysts have been extensively studied for decades for the water gas shift (WGS) reaction, a catalytic transformation central to a host of large volume processes that variously utilize or produce hydrogen. There remains considerable uncertainty as to how the specific features of the active metal-support interfacial bonding-perhaps most importantly the temporal dynamic changes occurring therein-serve to enable high activity and selectivity. Here we report the dynamic characteristics of a Pt/CeO2 system at the atomic level for the WGS reaction and specifically reveal the synergistic effects of metal-support bonding at the perimeter region. We find that the perimeter Pt-0-O vacancy-Ce3+ sites are formed in the active structure, transformed at working temperatures and their appearance regulates the adsorbate behaviors. We find that the dynamic nature of this site is a key mechanistic step for the WGS reaction. Revealing the structure and dynamics of active sites is essential to understand catalytic mechanisms. Here the authors demonstrate the dynamic nature of perimeter Pt-0-O vacancy-Ce3+ sites in Pt/CeO2 and the key effects of their dynamics on the mechanism of the water gas shift reaction.
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| 4. |
- Potter, Maggie M., et al.
(author)
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Autonomous Light Management in Flexible Photoelectrochromic Films Integrating High Performance Silicon Solar Microcells
- 2020
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In: ACS Applied Energy Materials. - : AMER CHEMICAL SOC. - 2574-0962. ; 3:2, s. 1540-1551
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Journal article (peer-reviewed)abstract
- Commercial smart window technologies for dynamic light and heat management in building and automotive environments traditionally rely on electrochromic (EC) materials powered by an external source. This design complicates building-scale installation requirements and substantially increases costs for applications in retrofit construction. Self-powered photoelectrochromic (PEC) windows are an intuitive alternative wherein a photovoltaic (PV) material is used to power the EC device, which modulates the transmission of the incident solar flux. The PV component in this application must be sufficiently transparent and produce enough power to efficiently modulate the EC device transmission. Here, we propose Si solar microcells (mu-cells) that are (i) small enough to be visually transparent to the eye and (ii) thin enough to enable flexible PEC devices. Visual transparency is achieved when Si mu-cells are arranged in high pitch (i.e., low-integration density) form factors while maintaining the advantages of a single-crystalline PV material (i.e., long lifetime and high performance). Additionally, the thin dimensions of these Si mu-cells enable fabrication on flexible substrates to realize flexible PEC devices. The current work demonstrates this concept using WO3 as the EC material and V2O5 as the ion storage layer, where each component is fabricated via sol-gel methods that afford improved prospects for scalability and tunability in comparison to thermal evaporation methods. The EC devices display fast switching times, as low as 8 s, with a modulation in transmission as high as 33%. Integration with two Si mu-cells in series (affording a 1.12 V output) demonstrates an integrated PEC module design with switching times of less than 3 min and a modulation in transmission of 32% with an unprecedented EC:PV areal ratio.
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| 5. |
- Potter, Maggie M., et al.
(author)
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Silicon Heterojunction Microcells
- 2021
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In: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 13:38, s. 45600-45608
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Journal article (peer-reviewed)abstract
- We report the design, fabrication, and characterization of silicon heterojunction microcells, a new type of photovoltaic cell that leverages high-efficiency bulk wafers in a microscale form factor, while also addressing the challenge of passivating microcell sidewalls to mitigate carrier recombination. We present synthesis methods exploiting either dry etching or laser cutting to realize microcells with native oxide-based edge passivation. Measured microcell performance for both fabrication processes is compared to that in simulations. We characterize the dependence of microcell open-circuit voltage (V-oc) on the cell area-perimeter ratio and examine synthesis processes that affect edge passivation quality, such as sidewall damage removal, the passivation material, and the deposition technique. We report the highest Si microcell V-oc to date (588 mV, for a 400 mu m x 400 mu m x 80 mu m device), demonstrate V-oc improvements with deposited edge passivation of up to 55 mV, and outline a pathway to achieve microcell efficiencies surpassing 15% for such device sizes.
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