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Iowa State University

2012

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Articles 1 - 28 of 28

Full-Text Articles in Physical Sciences and Mathematics

Effects Of Elevated Carbon Dioxide And Increased Temperature On Methane And Nitrous Oxide Fluxes: Evidence From Field Experiments, Feike A. Dijlstra, Stephen A. Prior, G. Brett Renion, H. Allen Torbert, Hanqin Tian, Chaoqun (Crystal) Lu, Rodney T. Venterea Dec 2012

Effects Of Elevated Carbon Dioxide And Increased Temperature On Methane And Nitrous Oxide Fluxes: Evidence From Field Experiments, Feike A. Dijlstra, Stephen A. Prior, G. Brett Renion, H. Allen Torbert, Hanqin Tian, Chaoqun (Crystal) Lu, Rodney T. Venterea

Chaoqun (Crystal) Lu

Climate change could alter terrestrial ecosystems, which are important sources and sinks of the potent green-house gases (GHGs) nitrous oxide (N2O) and methane (CH4), in ways that either stimulate or decrease the magnitude and duration of global warming. Using manipulative field experiments, we assessed how N2O and CH4 soil fluxes responded to a rise in atmospheric carbon dioxide (CO2) concentration and to increased air temperature. Nitrous oxide and CH4 responses varied greatly among studied ecosystems. Elevated CO2 often stimulated N2O emissions in fertilized systems and CH4 emissions in wetlands, peatlands, and rice paddy fields; both effects were stronger in clayey …

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Ultraviolet Photoinitiated On-Fiber Copolymerization Of Ionic Liquid Sorbent Coatings For Headspace And Direct Immersion Solid-Phase Microextraction, Tien D. Ho, Honglian Yu, William T.S. Cole, Jared L. Anderson Sep 2012

Ultraviolet Photoinitiated On-Fiber Copolymerization Of Ionic Liquid Sorbent Coatings For Headspace And Direct Immersion Solid-Phase Microextraction, Tien D. Ho, Honglian Yu, William T.S. Cole, Jared L. Anderson

Jared L. Anderson

A high-throughput method for the production of solid-phase microextraction (SPME) sorbent coatings via ultraviolet (UV) photoinitiated copolymerization of ionic liquid (IL) monomers on a fused silica support is described. The copolymerization of monocationic and dicationic IL cross-linkers was performed “on-fiber” using UV initiated free radical polymerization. Mixtures composed of various amounts of the IL cross-linker, UV initiator (DAROCUR 1173), and IL monomer were dip-coated onto an etched and derivatized fused silica support and placed in a high-capacity UV reactor. The method requires no organic dispersive solvent and is much more rapid compared to traditional methods in which polymeric ionic liquid …

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A Simple Two-Dimensional Model System To Study Electrostatic-Self-Assembly, Rebecca Cademartiri Aug 2012

A Simple Two-Dimensional Model System To Study Electrostatic-Self-Assembly, Rebecca Cademartiri

Rebecca Cademartiri

This paper surveys the variables controlling the lattice structure and charge in macroscopic Coulombic crystals made from electrically charged, millimeter-sized polymer objects (spheres, cubes, and cylinders). Mechanical agitation of these objects inside planar, bounded containers caused them to charge electrically through contact electrification, and to self-assemble. The processes of electrification and self-assembly, and the characteristics of the assemblies, depended on the type of motion used for agitation, on the type of materials used for the objects and the dish, on the size and shape of the objects and the dish, and on the number of objects. Each of the three …

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Replacing −Ch2ch2– With −Conh– Does Not Significantly Change Rates Of Charge Transport Through Agts-Sam//Ga2o3/Egain Junctions, Martin M. Thuo, William F. Reus, Felice C. Simeone, Choongik Kim, Michael D. Schulz, Hyo Jae Yoon, George M. Whitesides Jun 2012

Replacing −Ch2ch2– With −Conh– Does Not Significantly Change Rates Of Charge Transport Through Agts-Sam//Ga2o3/Egain Junctions, Martin M. Thuo, William F. Reus, Felice C. Simeone, Choongik Kim, Michael D. Schulz, Hyo Jae Yoon, George M. Whitesides

Martin M. Thuo

This paper describes physical-organic studies of charge transport by tunneling through self-assembled monolayers (SAMs), based on systematic variations of the structure of the molecules constituting the SAM. Replacing a −CH2CH2– group with a −CONH– group changes the dipole moment and polarizability of a portion of the molecule and has, in principle, the potential to change the rate of charge transport through the SAM. In practice, this substitution produces no significant change in the rate of charge transport across junctions of the structure AgTS-S(CH2)mX(CH2)nH//Ga2O3/EGaIn (TS = template stripped, X = −CH2CH2– or −CONH–, and EGaIn = eutectic alloy of gallium and …

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Century-Scale Responses Of Ecosystem Carbon Storage And Flux To Multiple Environmental Changes In The Southern United States, Hanqin Tian, Guangsheng Chen, Chi Zang, Mingliang Liu, Ge Sun, Arthur Chappelka, Wei Ren, Xiaofeng Xu, Chaoqun Lu, Shufen Pan, Hua Chen, Dafeng Hui, Steven Mcnulty, Graeme Lockaby, Eric Vance Jun 2012

Century-Scale Responses Of Ecosystem Carbon Storage And Flux To Multiple Environmental Changes In The Southern United States, Hanqin Tian, Guangsheng Chen, Chi Zang, Mingliang Liu, Ge Sun, Arthur Chappelka, Wei Ren, Xiaofeng Xu, Chaoqun Lu, Shufen Pan, Hua Chen, Dafeng Hui, Steven Mcnulty, Graeme Lockaby, Eric Vance

Chaoqun (Crystal) Lu

Terrestrial ecosystems in the southern United States (SUS) have experienced a complex set of changes in climate, atmospheric CO2 concentration, tropospheric ozone (O3), nitrogen (N) deposition, and land-use and land-cover change (LULCC) during the past century. Although each of these factors has received attention for its alterations on ecosystem carbon (C) dynamics, their combined effects and relative contributions are still not well understood. By using the Dynamic Land Ecosystem Model (DLEM) in combination with spatially explicit, long-term historical data series on multiple environmental factors, we examined the century-scale responses of ecosystem C storage and flux to multiple environmental changes in …

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A Reference-Free Algorithm For Computational Normalization Of Shotgun Sequencing Data, C. Titus Brown, Adina Howe, Qingpeng Zhang, Alexis B. Pyrkosz, Timothy H. Brom May 2012

A Reference-Free Algorithm For Computational Normalization Of Shotgun Sequencing Data, C. Titus Brown, Adina Howe, Qingpeng Zhang, Alexis B. Pyrkosz, Timothy H. Brom

Adina Howe

Deep shotgun sequencing and analysis of genomes, transcriptomes, amplified single-cell genomes, and metagenomes has enabled investigation of a wide range of organisms and ecosystems. However, sampling variation in short-read data sets and high sequencing error rates of modern sequencers present many new computational challenges in data interpretation. These challenges have led to the development of new classes of mapping tools and {\em de novo} assemblers. These algorithms are challenged by the continued improvement in sequencing throughput. We here describe digital normalization, a single-pass computational algorithm that systematizes coverage in shotgun sequencing data sets, thereby decreasing sampling variation, discarding redundant data, …

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The Sam, Not The Electrodes, Dominates Charge Transport In Metal-Monolayer//Ga2o3/Gallium–Indium Eutectic Junctions, William F. Reus, Martin M. Thuo, Nathan D. Shapiro, Christian A. Nijhuis, George M. Whitesides May 2012

The Sam, Not The Electrodes, Dominates Charge Transport In Metal-Monolayer//Ga2o3/Gallium–Indium Eutectic Junctions, William F. Reus, Martin M. Thuo, Nathan D. Shapiro, Christian A. Nijhuis, George M. Whitesides

Martin M. Thuo

The liquid–metal eutectic of gallium and indium (EGaIn) is a useful electrode for making soft electrical contacts to self-assembled monolayers (SAMs). This electrode has, however, one feature whose effect on charge transport has been incompletely understood: a thin (approximately 0.7 nm) film—consisting primarily of Ga2O3—that covers its surface when in contact with air. SAMs that rectify current have been measured using this electrode in AgTS-SAM//Ga2O3/EGaIn (where AgTS = template-stripped Ag surface) junctions. This paper organizes evidence, both published and unpublished, showing that the molecular structure of the SAM (specifically, the presence of an accessible molecular orbital asymmetrically located within the …

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Polycyclic Aromatic Triptycenes: Oxygen Substitution Cyclization Strategies, Brett Vanveller, Derek J. Schipper, Timothy M. Swager Apr 2012

Polycyclic Aromatic Triptycenes: Oxygen Substitution Cyclization Strategies, Brett Vanveller, Derek J. Schipper, Timothy M. Swager

Brett VanVeller

The cyclization and planarization of polycyclic aromatic hydrocarbons with concomitant oxygen substitution was achieved through acid catalyzed transetherification and oxygen-radical reactions. The triptycene scaffold enforces proximity of the alcohol and arene reacting partners and confers significant rigidity to the resulting π-system, expanding the tool set of iptycenes for materials applications.

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Multifactor Controls On Terrestrial N2o Flux Over North America From 1979 Through 2010, X. F. Xu, Hanqin Tian, G. S. Chen, M. L. Liu, Wei Ren, Chaoqun (Crystal) Lu, C. Zhang Apr 2012

Multifactor Controls On Terrestrial N2o Flux Over North America From 1979 Through 2010, X. F. Xu, Hanqin Tian, G. S. Chen, M. L. Liu, Wei Ren, Chaoqun (Crystal) Lu, C. Zhang

Chaoqun (Crystal) Lu

Nitrous oxide (N2O) is a potent greenhouse gas which also contributes to the depletion of stratospheric ozone (O3). However, the magnitude and underlying mechanisms for the spatiotemporal variations in the terrestrial sources of N2O are still far from certain. Using a process-based ecosystem model (DLEM – the Dynamic Land Ecosystem Model) driven by multiple global change factors, including climate variability, nitrogen (N) deposition, rising atmospheric carbon dioxide (CO2), tropospheric O3 pollution, N fertilizer application, and land conversion, this study examined the spatial and temporal variations in terrestrial N2O flux over North America and further attributed these variations to various driving …

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Measuring Markers Of Liver Function Using A Micropatterned Paper Device Designed For Blood From A Fingerstick, Sarah J. Vella, Patrick Beattie, Rebecca Cademartiri, Anna Laromaine, Andres W. Martinez, Scott T. Phillips, Katherine A. Mirica, George M. Whitesides Mar 2012

Measuring Markers Of Liver Function Using A Micropatterned Paper Device Designed For Blood From A Fingerstick, Sarah J. Vella, Patrick Beattie, Rebecca Cademartiri, Anna Laromaine, Andres W. Martinez, Scott T. Phillips, Katherine A. Mirica, George M. Whitesides

Rebecca Cademartiri

This paper describes a paper-based microfluidic device that measures two enzymatic markers of liver function (alkaline phosphatase, ALP, and aspartate aminotransferase, AST) and total serum protein. A device consists of four components: (i) a top plastic sheet, (ii) a filter membrane, (iii) a patterned paper chip containing the reagents necessary for analysis, and (iv) a bottom plastic sheet. The device performs both the sample preparation (separating blood plasma from erythrocytes) and the assays; it also enables both qualitative and quantitative analysis of data. The data obtained from the paper-microfluidic devices show standard deviations in calibration runs and “spiked” standards that …

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Statistical Tools For Analyzing Measurements Of Charge Transport, William F. Reus, Christian A. Nijhuis, Jabulani R. Barber, Martin M. Thuo, Simon Tricard, George M. Whitesides Feb 2012

Statistical Tools For Analyzing Measurements Of Charge Transport, William F. Reus, Christian A. Nijhuis, Jabulani R. Barber, Martin M. Thuo, Simon Tricard, George M. Whitesides

Martin M. Thuo

This paper applies statistical methods to analyze the large, noisy data sets produced in measurements of tunneling current density (J) through self-assembled monolayers (SAMs) in large-area junctions. It describes and compares the accuracy and precision of procedures for summarizing data for individual SAMs, for comparing two or more SAMs, and for determining the parameters of the Simmons model (β and J0). For data that contain significant numbers of outliers (i.e., most measurements of charge transport), commonly used statistical techniques—e.g., summarizing data with arithmetic mean and standard deviation and fitting data using a linear, least-squares algorithm—are prone to large errors. The …

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Electrical Resistance Of Agts–S(Ch2)N−1ch3//Ga2o3/Egain Tunneling Junctions, Ludovico Cademartiri, Martin M. Thuo, Christian A. Nijhuis, William F. Reus, Simon Tricard, Jubulani R. Barber, Rana N.S. Sodhi, Peter Brodersen, Choongik Kim, Ryan C. Chiechi, George M. Whitesides Feb 2012

Electrical Resistance Of Agts–S(Ch2)N−1ch3//Ga2o3/Egain Tunneling Junctions, Ludovico Cademartiri, Martin M. Thuo, Christian A. Nijhuis, William F. Reus, Simon Tricard, Jubulani R. Barber, Rana N.S. Sodhi, Peter Brodersen, Choongik Kim, Ryan C. Chiechi, George M. Whitesides

Martin M. Thuo

Tunneling junctions having the structure AgTS–S(CH2)n−1CH3//Ga2O3/EGaIn allow physical–organic studies of charge transport across self-assembled monolayers (SAMs). In ambient conditions, the surface of the liquid metal electrode (EGaIn, 75.5 wt % Ga, 24.5 wt % In, mp 15.7 °C) oxidizes and adsorbs―like other high-energy surfaces―adventitious contaminants. The interface between the EGaIn and the SAM thus includes a film of metal oxide, and probably also organic material adsorbed on this film; this interface will influence the properties and operation of the junctions. A combination of structural, chemical, and electrical characterizations leads to four conclusions about AgTS–S(CH2)n−1CH3//Ga2O3/EGaIn junctions. (i) The oxide is ∼0.7 …

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In Situ Phytoplankton Analysis: There’S Plenty Of Room At The Bottom, Jeffrey S. Erickson, Nicole N. Hashemi, James M. Sullivan, Alan D. Weidemann, Frances S. Ligler Jan 2012

In Situ Phytoplankton Analysis: There’S Plenty Of Room At The Bottom, Jeffrey S. Erickson, Nicole N. Hashemi, James M. Sullivan, Alan D. Weidemann, Frances S. Ligler

Nastaran Hashemi

Approximately 70% of the earth is covered with water, within which the most dominant organism is phytoplankton. Not only is phytoplankton at the base of the marine food web, but it also fixes excess carbon dioxide and regulates sulfur on a global scale.1 Changes in phytoplankton populations have been linked to toxicity to humans and marine life, pollution, and global climate change.2 Routine monitoring of both fresh and salt water ecosystems has been taking place formany years, with consortia set up explicitly for this purpose. Consensus indicates that five categories of information are useful for early warning systems.3,4 These are …

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Bacterial Isolation By Lectin-Modified Microengines, Susana Campuzano, Jahir Orozco, Daniel Kagan, Maria Guix, Wei Gao, Sirilak Sattayasamitsathit, Jonathan C. Claussen, Arben Merkoci, Joseph Wang Jan 2012

Bacterial Isolation By Lectin-Modified Microengines, Susana Campuzano, Jahir Orozco, Daniel Kagan, Maria Guix, Wei Gao, Sirilak Sattayasamitsathit, Jonathan C. Claussen, Arben Merkoci, Joseph Wang

Jonathan C. Claussen

New template-based self-propelled gold/nickel/polyaniline/platinum (Au/Ni/PANI/Pt) microtubular engines, functionalized with the Concanavalin A (ConA) lectin bioreceptor, are shown to be extremely useful for the rapid, real-time isolation of Escherichia coli (E. coli) bacteria from fuel-enhanced environmental, food, and clinical samples. These multifunctional microtube engines combine the selective capture of E. coli with the uptake of polymeric drug-carrier particles to provide an attractive motion-based theranostics strategy. Triggered release of the captured bacteria is demonstrated by movement through a low-pH glycine-based dissociation solution. The smaller size of the new polymer-metal microengines offers convenient, direct, and label-free optical visualization of the captured bacteria and …

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Food Benefit And Climate Warming Potential Of Nitrogen Fertilizer Uses In China, Hanqin Tian, Chaoqun (Crystal) Lu, Jerry Melillo, Wei Ren, Yao Huang, Xiaofeng Xu, Mingliang Liu, Chi Zhang, Guangsheng Chen, Shufen Pan, Jiyuan Liu, John Reilly Jan 2012

Food Benefit And Climate Warming Potential Of Nitrogen Fertilizer Uses In China, Hanqin Tian, Chaoqun (Crystal) Lu, Jerry Melillo, Wei Ren, Yao Huang, Xiaofeng Xu, Mingliang Liu, Chi Zhang, Guangsheng Chen, Shufen Pan, Jiyuan Liu, John Reilly

Chaoqun (Crystal) Lu

Chemical nitrogen (N) fertilizer has long been used to help meet the increasing food demands in China, the top N fertilizer consumer in the world. Growing concerns have been raised on the impacts of N fertilizer uses on food security and climate change, which is lack of quantification. Here we use a carbon–nitrogen (C–N) coupled ecosystem model, to quantify the food benefit and climate consequence of agronomic N addition in China over the six decades from 1949 to 2008. Results show that N fertilizer-induced crop yield and soil C sequestration had reached their peaks, while nitrous oxide (N2O) emission continued …

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Effect Of Nitrogen Deposition On China's Terrestrial Carbon Uptake In The Context Of Multifactor Environmental Changes, Chaoqun (Crystal) Lu, Hanqin Tian, Mingliang Liu, Wei Ren, Xiaofeng Xu, Guangsheng Chen, Chi Zhang Jan 2012

Effect Of Nitrogen Deposition On China's Terrestrial Carbon Uptake In The Context Of Multifactor Environmental Changes, Chaoqun (Crystal) Lu, Hanqin Tian, Mingliang Liu, Wei Ren, Xiaofeng Xu, Guangsheng Chen, Chi Zhang

Chaoqun (Crystal) Lu

The amount of atmospheric nitrogen (N) deposited on the land surface has increased globally and by nearly five times in China from 1901 to 2005. Little is known about how elevated reactive N input has affected the carbon (C) sequestration capability of China's terrestrial ecosystems, largely due to the lack of reliable data on N deposition. Here we have used a newly developed data set of historical N deposition at a spatial resolution of 10 km × 10 km in combination with other gridded historical information on climate, atmospheric composition, land use, and land management practices to drive a process-based …

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Contemporary And Projected Biogenic Fluxes Of Methane And Nitrous Oxide In North American Terrestrial Ecosystems, Hanqin Tian, Chaoqun (Crystal) Lu, Guangsheng Chen, Bo Tao, Shufen Pan, Stephen J. Del Grosso, Xiaofeng Xu, Lori Bruhwiler, Steven C. Wofsy, Eric A. Kort, Stephen A. Prior Jan 2012

Contemporary And Projected Biogenic Fluxes Of Methane And Nitrous Oxide In North American Terrestrial Ecosystems, Hanqin Tian, Chaoqun (Crystal) Lu, Guangsheng Chen, Bo Tao, Shufen Pan, Stephen J. Del Grosso, Xiaofeng Xu, Lori Bruhwiler, Steven C. Wofsy, Eric A. Kort, Stephen A. Prior

Chaoqun (Crystal) Lu

Accurately estimating biogenic methane (CH4) and nitrous oxide (N2O) fluxes in terrestrial ecosystems is critical for resolving global budgets of these greenhouse gases (GHGs) and continuing to mitigate climate warming. Here, we assess contemporary biogenic CH4 and N2O budgets and probable climate-change-related impacts on CH4 and N2O emissions in terrestrial North America. Multi-approach estimations show that, during 1990–2010, biogenic CH4 emissions ranged from 0.159 to 0.502 petagrams of carbon dioxide (CO2) equivalents per year (Pg CO2eq yr–1, where 1 Pg = 1 × 1015 g) and N2O emissions ranged from 0.802 to 1.016 Pg CO2eq yr–1, which offset 47–166% of …

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Mox/Cnts Hetero-Structures For Gas Sensing Applications: Role Of Cnts Defects, G. Neri, S. G. Leonardi, N. Donato, C. Marichy, Jean-Philippe Tessonnier, M.-G. Willinger, Kyeong-Hwan Lee, N. Pinna Jan 2012

Mox/Cnts Hetero-Structures For Gas Sensing Applications: Role Of Cnts Defects, G. Neri, S. G. Leonardi, N. Donato, C. Marichy, Jean-Philippe Tessonnier, M.-G. Willinger, Kyeong-Hwan Lee, N. Pinna

Jean-Philippe Tessonnier

The preparation, characterization and sensing properties of CNT composites with a thin metal oxide (MOx) surface layer is presented. Atomic layer deposition (ALD) was applied for the coating of the inner and outer CNTs walls with thin films of ZnO and SnO2 of precisely controlled thicknesses. Differently treated CNTs with different degree of surface functionalization were used as support for the oxide films. The sensing properties of the obtained composite materials towards NO2 were investigated and related to the morphological and microstructural characteristics of both the coating and support. SnO2-based composites on CNTs treated at 700 °C show enhanced performance …

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The Use Of A Ditopic Gd(Iii) Paramagnetic Probe For Investigating Α-Bungarotoxin Surface Accessibility, Andrea Bernini, Ottavia Spiga, Vincenzo Venditti, Filippo Prischi, Mauro Botta, Gianluca Croce, Angela Pui-Ling Tong, Wing-Talk Wong, Neri Niccolai Jan 2012

The Use Of A Ditopic Gd(Iii) Paramagnetic Probe For Investigating Α-Bungarotoxin Surface Accessibility, Andrea Bernini, Ottavia Spiga, Vincenzo Venditti, Filippo Prischi, Mauro Botta, Gianluca Croce, Angela Pui-Ling Tong, Wing-Talk Wong, Neri Niccolai

Vincenzo Venditti

Protein surface accessibility is a critical parameter which drives all intermolecular interaction processes. In this respect a big deal of information has been derived by analyzing paramagnetic perturbation profiles obtained from NMR protein spectra, particularly in the case that the effects due to different soluble paramagnets can be compared. Here Gd2L7, a neutral ditopic paramagnetic NMR probe, has been characterized in terms of structure and relaxivity and its paramagnetic perturbations on α-bungarotoxin CαH signals in 1H–13C HSQC (heteronuclear single quantum coherence) spectra have been analyzed. Then, these signal attenuations have been compared with the ones previously obtained in the presence …

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An Efficient Protocol For Incorporation Of An Unnatural Amino Acid In Perdeuterated Recombinant Proteins Using Glucose-Based Media, Vincenzo Venditti, Nicolas L. Fawzi, G. Marius Clore Jan 2012

An Efficient Protocol For Incorporation Of An Unnatural Amino Acid In Perdeuterated Recombinant Proteins Using Glucose-Based Media, Vincenzo Venditti, Nicolas L. Fawzi, G. Marius Clore

Vincenzo Venditti

The in vivo incorporation of unnatural amino acids into proteins is a well-established technique requiring an orthogonal tRNA/aminoacyl-tRNA synthetase pair specific for the unnatural amino acid that is incorporated at a position encoded by a TAG amber codon. Although this technology provides unique opportunities to engineer protein structures, poor protein yields are usually obtained in deuterated media, hampering its application in the protein NMR field. Here, we describe a novel protocol for incorporating unnatural amino acids into fully deuterated proteins using glucose-based media (which are relevant to the production, for example, of amino acid-specific methyl-labeled proteins used in the study …

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Conformational Selection And Substrate Binding Regulate The Monomer/Dimer Equilibrium Of The C-Terminal Domain Of Escherichia Coli Enzyme I, Vincenzo Venditti, G. Marius Clore Jan 2012

Conformational Selection And Substrate Binding Regulate The Monomer/Dimer Equilibrium Of The C-Terminal Domain Of Escherichia Coli Enzyme I, Vincenzo Venditti, G. Marius Clore

Vincenzo Venditti

The bacterial phosphotransferase system (PTS) is a signal transduction pathway that couples phosphoryl transfer to active sugar transport across the cell membrane. The PTS is initiated by the binding of phosphoenolpyruvate (PEP) to the C-terminal domain (EIC) of enzyme I (EI), a highly conserved protein that is common to all sugar branches of the PTS. EIC exists in a dynamic monomer/dimer equilibrium that is modulated by ligand binding and is thought to regulate the overall PTS. Isolation of EIC has proven challenging, and conformational dynamics within the EIC domain during the catalytic cycle are still largely unknown. Here, we present …

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Determination Of The Solubilizing Character Of 1-Methoxyethyl-1- Methylpiperidinium Tris(Pentafluoroethyl)Trifluorophosphate Based On The Abraham Solvation Parameter Model, Pamela Twu, Jared L. Anderson, Timothy W. Stephens, William E. Acree Jr., Michael H. Abraham Jan 2012

Determination Of The Solubilizing Character Of 1-Methoxyethyl-1- Methylpiperidinium Tris(Pentafluoroethyl)Trifluorophosphate Based On The Abraham Solvation Parameter Model, Pamela Twu, Jared L. Anderson, Timothy W. Stephens, William E. Acree Jr., Michael H. Abraham

Jared L. Anderson

Chromatographic retention data were measured for a chemically diverse set of organic solutes on an anhydrous 1-methoxyethyl-1-methylpiperidinium tris(pentafluoroethyl)trifluorophosphate, ([MeoeMPip]+ [FAP]–), stationary phase at both 323 K and 353 K. The experimental retention factors were combined with previously published thermodynamic data and gas-to-water partition coefficient data to yield gas-to-anhydrous ionic liquid (IL) and water-to-anhydrous IL partition coefficients. The three sets of partition coefficient data were analyzed in accordance with the Abraham model. The Abraham model correlations that were determined in the present study describe the observed gas-to-([MeoeMPip]+[FAP]–) (log K) and water-to-([MeoeMPip]+[FAP]–) (log P) partition coefficient data to within average standard deviations …

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Materials For Diabetes Therapeutics, Kaitlin M. Bratlie, Roger L. York, Michael A. Invernale, Robert Langer, Daniel G. Anderson Jan 2012

Materials For Diabetes Therapeutics, Kaitlin M. Bratlie, Roger L. York, Michael A. Invernale, Robert Langer, Daniel G. Anderson

Kaitlin M. Bratlie

This review is focused on the materials and methods used to fabricate closedloop systems for type 1 diabetes therapy. Herein, we give a brief overview of current methods used for patient care and discuss two types of possible treatments and the materials used for these therapies-(i) artificial pancreases, comprised of insulin producing cells embedded in a polymeric biomaterial, and (ii) totally synthetic pancreases formulated by integrating continuous glucose monitors with controlled insulin release through degradable polymers and glucose-responsive polymer systems. Both the artificial and the completely synthetic pancreas have two major design requirements: the device must be both biocompatible and …

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Scaling Metagenome Sequence Assembly With Probabilistic De Bruijn Graphs, Jason Pell, Rosangela Canino-Koning, Adina Howe, James Tiedje, C T. Brown Jan 2012

Scaling Metagenome Sequence Assembly With Probabilistic De Bruijn Graphs, Jason Pell, Rosangela Canino-Koning, Adina Howe, James Tiedje, C T. Brown

Adina Howe

Deep sequencing has enabled the investigation of a wide range of environmental microbial ecosystems, but the high memory requirements for de novo assembly of short-read shotgun sequencing data from these complex populations are an increasingly large practical barrier. Here we introduce a memory-efficient graph representation with which we can analyze the k-mer connectivity of metagenomic samples. The graph representation is based on a probabilistic data structure, a Bloom filter, that allows us to efficiently store assembly graphs in as little as 4 bits per k-mer, albeit inexactly. We show that this data structure accurately represents DNA assembly graphs in low …

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Overview Of Fuel Ethanol Production And Distillers Grains, Kurt A. Rosentrater Jan 2012

Overview Of Fuel Ethanol Production And Distillers Grains, Kurt A. Rosentrater

Kurt A. Rosentrater

Modern societies face many challenges, including growing populations, increased demands for food, clothing, housing, consumer goods, and the concomitant raw materials required to produce all of these. Additionally, there is a growing need for energy, which is most easily met by use of fossil fuels (e.g., coal, natural gas, and petroleum). In 2008, the overall U.S. demand for energy was 99.3 x 1015 Btu (1.05 x 1014 MJ); 84% of this was supplied by fossil sources (U.S. EIA, 2009). Transportation fuels accounted for 28% of all energy consumed during this time, and nearly 97% of this came from fossil sources. …

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Manufacturing Of Fuel Ethanol And Distillers Grains—Current And Evolving Processes, Kurt A. Rosentrater, Klein Ileleji, David B. Johnson Jan 2012

Manufacturing Of Fuel Ethanol And Distillers Grains—Current And Evolving Processes, Kurt A. Rosentrater, Klein Ileleji, David B. Johnson

Kurt A. Rosentrater

Before examining all of the different possible uses of distillers dried grains with solubles (DDGS), a discussion regarding ethanol and DDGS production methods is warranted. This chapter will cover current production processes and some of the new practices that have been developed and are being adopted at plants, including front-end fractionation and back-end fractionation. Additionally, standard coproduct definitions will be discussed, as they govern the marketing and sales of these materials.

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Labeling And Monitoring The Distribution Of Anchoring Sites On Functionalized Cnts By Atomic Layer Deposition, Catherine Marichy, Jean-Philippe Tessonnier, Marta C. Ferro, Kyeong-Hwan Lee, Robert Schlogl, Nicola Pinna, Marc-Georg Willinger Jan 2012

Labeling And Monitoring The Distribution Of Anchoring Sites On Functionalized Cnts By Atomic Layer Deposition, Catherine Marichy, Jean-Philippe Tessonnier, Marta C. Ferro, Kyeong-Hwan Lee, Robert Schlogl, Nicola Pinna, Marc-Georg Willinger

Jean-Philippe Tessonnier

The chemical inertness of graphite and, in the case of tubes, of rolled up few layer graphene sheets, requires some degree of "defect engineering" for the fabrication of carbon based heterostructured materials. It is shown that atomic layer deposition provides a means to specifically label anchoring sites and can be used to characterize the surface functionality of differently treated carbon nanotubes. Direct observation of deposited titania by analytical transmission electron microscopy reveals the location and density of anchoring sites as well as structure related concentrations of functional groups on the surface of the tubes. Controlled functionalization of the tubes therefore …

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Toward A Scientific Understanding Of Ddgs, Keshun Liu, Kurt A. Rosentrater Jan 2012

Toward A Scientific Understanding Of Ddgs, Keshun Liu, Kurt A. Rosentrater

Kurt A. Rosentrater

Recently, many people have asked what the fuel ethanol industry is going to do about the growing piles of nonfermented leftovers. Actually this question has been around for quite some time. As early as the 1940s, one report stated that "Grain distillers have developed equipment and an attractive market for their recovered grains" (Boruff, 1947), while another report described that "Distillers are recovering, drying, and marketing their destarched grain stillage as distillers dried grains and dried solubles" (Boruff, 1952). So it appears that a viable solution had already been developed as far back as the 1940s. And by the early …

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