Search Menu
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information
Search Scholarly Publications

8 Search Results

Sorted by Relevance
Save Results
...

  1. Microbiome differences in sugarcane and metabolically engineered oilcane accessions and their implications for bioenergy production

    Yang, Jihoon ; Sooksa-nguan, Thanwalee ; Kannan, Baskaran ; ... - Biotechnology for Biofuels and Bioproducts
    Abstract Oilcane is a metabolically engineered sugarcane ( Saccharum spp. hybrid) that hyper-accumulates lipids in its vegetable biomass to provide an advanced feedstock for biodiesel production. The potential impact of hyper-accumulation of lipids in vegetable biomass on microbiomes and the consequences of altered microbiomes on plant growth and lipid accumulation have not been explored so far. Here, we explore differences in the microbiome structure of different oilcane accessions and non-modified sugarcane. 16S SSU rRNA and ITS rRNA amplicon sequencing were performed to compare the characteristics of the microbiome structure from different plant compartments (leaf, stem, root, rhizosphere, and bulk soil)more » of four greenhouse-grown oilcane accessions and non-modified sugarcane. Significant differences were only observed in the bacterial microbiomes. In leaf and stem microbiomes, more than 90% of the entire microbiome of non-modified sugarcane and oilcane was dominated by similar core taxa. Taxa associated with Proteobacteria led to differences in the non-modified sugarcane and oilcane microbiome structure. While differences were observed between multiple accessions, accession 1566 was notable in that it was consistently observed to differ in its microbial membership than other accessions and had the lowest abundance of taxa associated with plant-growth-promoting bacteria. Accession 1566 is also unique among oilcane accessions in that it has the highest constitutive expression of the WRI 1 transgene. The WRI 1 transcription factor is known to contribute to significant changes in the global gene expression profile, impacting plant fatty acid biosynthesis and photomorphogenesis. This study reveals for the first time that genetically modified oilcanes associate with distinct microbiomes. Our findings suggest potential relationships between core taxa, biomass yield, and TAG in oilcane accessions and support further research on the relationship between plant genotypes and their microbiomes.« less

  2. Decoding the 2D IR spectrum of the aqueous proton with high-level VSCF/VCI calculations

    Carpenter, William B. ; Yu, Qi ; Hack, John H. ; ... - Journal of Chemical Physics
    The aqueous proton is a common and long-studied species in chemistry, yet there is currently intense interest devoted to understanding its hydration structure and transport dynamics. Typically described in terms of two limiting structures observed in gas-phase clusters, the Zundel H5O2+ and Eigen H9O4+ ions, the aqueous structure is less clear due to the heterogeneity of hydrogen bonding environments and room-temperature structural fluctuations in water. The linear infrared (IR) spectrum, which reports on structural configurations, is challenging to interpret because it appears as a continuum of absorption, and the underlying vibrational modes are strongly anharmonically coupled to each other. Recentmore » two-dimensional IR (2D IR) experiments presented strong evidence for asymmetric Zundel-like motifs in solution, but true structure–spectrum correlations are missing and complicated by the anharmonicity of the system. In this study, we employ high-level vibrational self-consistent field/virtual state configuration interaction calculations to demonstrate that the 2D IR spectrum reports on a broad distribution of geometric configurations of the aqueous proton. We find that the diagonal 2D IR spectrum around 1200 cm–1 is dominated by the proton stretch vibrations of Zundel-like and intermediate geometries, broadened by the heterogeneity of aqueous configurations. There is a wide distribution of multidimensional potential shapes for the proton stretching vibration with varying degrees of potential asymmetry and confinement. In conclusion, we find specific cross peak patterns due to aqueous Zundel-like species. These studies provide clarity on highly debated spectral assignments and stringent spectroscopic benchmarks for future simulations.« less

  3. Assessing the Viability of Recovery of Hydroxycinnamic Acids from Lignocellulosic Biorefinery Alkaline Pretreatment Waste Streams

    Karlen, Steven D. ; Fasahati, Peyman ; Mazaheri, Mona ; ... - ChemSusChem

  4. IR spectral assignments for the hydrated excess proton in liquid water

    Biswas, Rajib ; Carpenter, William ; Fournier, Joseph A. ; ... - Journal of Chemical Physics
    The local environmental sensitivity of infrared (IR) spectroscopy to a hydrogen-bonding structure makes it a powerful tool for investigating the structure and dynamics of excess protons in water. Although of significant interest, the line broadening that results from the ultrafast evolution of different solvated proton-water structures makes the assignment of liquid-phase IR spectra a challenging task. In this paper, we apply a normal mode analysis using density functional theory of thousands of proton-water clusters taken from reactive molecular dynamics trajectories of the latest generation multistate empirical valence bond proton model (MS-EVB 3.2). These calculations are used to obtain a vibrationalmore » density of states and IR spectral density, which are decomposed on the basis of solvated proton structure and the frequency dependent mode character. Decompositions are presented on the basis of the proton sharing parameter δ, often used to distinguish Eigen and Zundel species, the stretch and bend character of the modes, the mode delocalization, and the vibrational mode symmetry. We find there is a wide distribution of vibrational frequencies spanning 1200-3000 cm-1 for every local proton configuration, with the region 2000-2600 cm-1 being mostly governed by the distorted Eigen-like configuration. Finally, we find a continuous red shift of the special-pair O∙∙∙H+∙∙∙O stretching frequency, and an increase in the flanking water bending intensity with decreasing δ. Also, we find that the flanking water stretch mode of the Zundel-like species is strongly mixed with the flanking water bend, and the special pair proton oscillation band is strongly coupled with the bend modes of the central H 5 O 2 + moiety.« less

  5. Acid additives enhancing the conductivity of spiro-OMeTAD toward high-efficiency and hysteresis-less planar perovskite solar cells

    Li, Zhen ; Tinkham, Jonathan ; Schulz, Philip ; ... - Advanced Energy Materials
    A general doping strategy, using a wide range of acids with different pKa values as additive, is demonstrated to enhance the conductivity of spiro-OMeTAD, the dominant hole transport material in perovskite solar cells (PSCs). Here, hysteresis-less planar PSCs with ≈19% efficiency and better open-circuit voltage and fill factor is achieved with acid doped spiro-OMeTAD.

  6. Global structure search for molecules on surfaces: Efficient sampling with curvilinear coordinates

    Krautgasser, Konstantin ; Panosetti, Chiara ; Palagin, Dennis ; ... - Journal of Chemical Physics
    Efficient structure search is a major challenge in computational materials science. Here, we present a modification of the basin hopping global geometry optimization approach that uses a curvilinear coordinate system to describe global trial moves. This approach has recently been shown to be efficient in structure determination of clusters [C. Panosetti et al., Nano Lett. 15, 8044–8048 (2015)] and is here extended for its application to covalent, complex molecules and large adsorbates on surfaces. The employed automatically constructed delocalized internal coordinates are similar to molecular vibrations, which enhances the generation of chemically meaningful trial structures. By introducing flexible constraints andmore » local translation and rotation of independent geometrical subunits, we enable the use of this method for molecules adsorbed on surfaces and interfaces. For two test systems, trans-β-ionylideneacetic acid adsorbed on a Au(111) surface and methane adsorbed on a Ag(111) surface, we obtain superior performance of the method compared to standard optimization moves based on Cartesian coordinates.« less

  7. Three-dimensional imaging of cholesterol and sphingolipids within a Madin-Darby canine kidney cell

    Yeager, Ashley N. ; Weber, Peter K. ; Kraft, Mary L. - Biointerphases
    Metabolic stable isotope incorporation and secondary ion mass spectrometry(SIMS) depth profiling performed on a Cameca NanoSIMS 50 were used to image the 18O-cholesterol and 15N-sphingolipid distributions within a portion of a Madin-Darby canine kidney (MDCK) cell. Three-dimensional representations of the component-specific isotope distributions show clearly defined regions of 18O-cholesterol and 15N-sphingolipid enrichment that seem to be separate subcellular compartments. Furthermore, the low levels of nitrogen-containing secondary ions detected at the 18O-enriched regions suggest that these 18O-cholesterol-rich structures may be lipiddroplets, which have a core consisting of cholesterol esters and triacylglycerides.

  8. Proton or Metal? The H/D Exchange of Arenes in Acidic Solvents

    Munz, Dominik ; Webster-Gardiner, Michael ; Fu, Ross ; ... - ACS Catalysis
    In this work, the H/D exchange of arenes in acidic media by transition and main group metal complexes and common inorganic salts was studied. The influence of Lewis acidity, anions, charge, and ligands was evaluated. The results indicate that the deter-mination of H/D exchange activity in acidic media is not related to the formation of metal – carbon bonds (i.e., C–H activation). The combined experimental data (regioselectivity, activation energy, kinetics, isotope effects, solvent effects) and DFT calculations point toward a proton catalysis mechanism. Thus, highly Lewis acidic metal compounds, such as alumi-num(III) triflate, were extraordinarily active for the H/D ex-changemore » reactions. Indeed, the degree of H/D exchange reactivi-ty allows for a comparative measurement of Lewis acidities.« less
...
Search for:
All Records
Subject
hypohalous acids
Refine by:
Article Type
Availability
Journal
more less
Creator / Author
more less
Publication Date
Research Organization
more less