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Showing papers by "Pacific Northwest National Laboratory published in 2010"


Journal ArticleDOI
TL;DR: Graphene has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and mass production).
Abstract: Graphene, emerging as a true 2-dimensional material, has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and mass production). This article selectively reviews recent advances in graphene-based electrochemical sensors and biosensors. In particular, graphene for direct electrochemistry of enzyme, its electrocatalytic activity toward small biomolecules (hydrogen peroxide, NADH, dopamine, etc.), and graphenebased enzyme biosensors have been summarized in more detail; Graphene-based DNA sensing and environmental analysis have been discussed. Future perspectives in this rapidly developing field are also discussed.

2,866 citations


Journal ArticleDOI
Koji Nakamura1, K. Hagiwara, Ken Ichi Hikasa2, Hitoshi Murayama3  +180 moreInstitutions (92)
TL;DR: In this article, a biennial review summarizes much of particle physics using data from previous editions, plus 2158 new measurements from 551 papers, they list, evaluate and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons.
Abstract: This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2158 new measurements from 551 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on neutrino mass, mixing, and oscillations, QCD, top quark, CKM quark-mixing matrix, V-ud & V-us, V-cb & V-ub, fragmentation functions, particle detectors for accelerator and non-accelerator physics, magnetic monopoles, cosmological parameters, and big bang cosmology.

2,788 citations


Journal ArticleDOI
07 Apr 2010-ACS Nano
TL;DR: A facile strategy to prepare N-doped graphene by using nitrogen plasma treatment of graphene synthesized via a chemical method is reported, which has displayed high electrocatalytic activity for reduction of hydrogen peroxide and fast direct electron transfer kinetics for glucose oxidase.
Abstract: Chemical doping with foreign atoms is an effective method to intrinsically modify the properties of host materials. Among them, nitrogen doping plays a critical role in regulating the electronic properties of carbon materials. Recently, graphene, as a true two-dimensional carbon material, has shown fascinating applications in bioelectronics and biosensors. In this paper, we report a facile strategy to prepare N-doped graphene by using nitrogen plasma treatment of graphene synthesized via a chemical method. Meanwhile, a possible schematic diagram has been proposed to detail the structure of N-doped graphene. By controlling the exposure time, the N percentage in host graphene can be regulated, ranging from 0.11 to 1.35%. Moreover, the as-prepared N-doped graphene has displayed high electrocatalytic activity for reduction of hydrogen peroxide and fast direct electron transfer kinetics for glucose oxidase. The N-doped graphene has further been used for glucose biosensing with concentrations as low as 0.01 mM ...

1,907 citations


Journal ArticleDOI
TL;DR: The maximum sustainable technical potential of biochar to mitigate climate change is estimated, which shows that it has a larger climate-change mitigation potential than combustion of the same sustainably procured biomass for bioenergy, except when fertile soils are amended while coal is the fuel being offset.
Abstract: Production of biochar (the carbon (C)-rich solid formed by pyrolysis of biomass) and its storage in soils have been suggested as a means of abating climate change by sequestering carbon, while simultaneously providing energy and increasing crop yields. Substantial uncertainties exist, however, regarding the impact, capacity and sustainability of biochar at the global level. In this paper we estimate the maximum sustainable technical potential of biochar to mitigate climate change. Annual net emissions of carbon dioxide (CO 2 ), methane and nitrous oxide could be reduced by a maximum of 1.8 Pg CO 2 -C equivalent (CO 2 -C e ) per year (12 % of current anthropogenic CO 2 -C e emissions; 1 Pg = 1 Gt), and total net emissions over the course of a century by 130 Pg CO 2 -C e , without endangering food security, habitat or soil conservation. Biochar has a larger climate-change mitigation potential than combustion of the same sustainably procured biomass for bioenergy, except when fertile soils are amended while coal is the fuel being offset.

1,893 citations


Journal ArticleDOI
10 Dec 2010-Science
TL;DR: Because lithiation-induced volume expansion, plasticity, and pulverization of electrode materials are the major mechanical effects that plague the performance and lifetime of high-capacity anodes in lithium-ion batteries, these observations provide important mechanistic insight for the design of advanced batteries.
Abstract: We report the creation of a nanoscale electrochemical device inside a transmission electron microscope--consisting of a single tin dioxide (SnO(2)) nanowire anode, an ionic liquid electrolyte, and a bulk lithium cobalt dioxide (LiCoO(2)) cathode--and the in situ observation of the lithiation of the SnO(2) nanowire during electrochemical charging. Upon charging, a reaction front propagated progressively along the nanowire, causing the nanowire to swell, elongate, and spiral. The reaction front is a "Medusa zone" containing a high density of mobile dislocations, which are continuously nucleated and absorbed at the moving front. This dislocation cloud indicates large in-plane misfit stresses and is a structural precursor to electrochemically driven solid-state amorphization. Because lithiation-induced volume expansion, plasticity, and pulverization of electrode materials are the major mechanical effects that plague the performance and lifetime of high-capacity anodes in lithium-ion batteries, our observations provide important mechanistic insight for the design of advanced batteries.

1,398 citations


Journal ArticleDOI
18 Mar 2010-Nature
TL;DR: Comparison of genomes of three phenotypically diverse Fusarium species revealed lineage-specific genomic regions in F. oxysporum that include four entire chromosomes and account for more than one-quarter of the genome, putting the evolution of fungal pathogenicity into a new perspective.
Abstract: Fusarium species are among the most important phytopathogenic and toxigenic fungi. To understand the molecular underpinnings of pathogenicity in the genus Fusarium, we compared the genomes of three phenotypically diverse species: Fusarium graminearum, Fusarium verticillioides and Fusarium oxysporum f. sp. lycopersici. Our analysis revealed lineage-specific (LS) genomic regions in F. oxysporum that include four entire chromosomes and account for more than one-quarter of the genome. LS regions are rich in transposons and genes with distinct evolutionary profiles but related to pathogenicity, indicative of horizontal acquisition. Experimentally, we demonstrate the transfer of two LS chromosomes between strains of F. oxysporum, converting a non-pathogenic strain into a pathogen. Transfer of LS chromosomes between otherwise genetically isolated strains explains the polyphyletic origin of host specificity and the emergence of new pathogenic lineages in F. oxysporum. These findings put the evolution of fungal pathogenicity into a new perspective.

1,386 citations


Journal ArticleDOI
TL;DR: The dramatic delivery, protection, and sensing capabilities of GO-nS in living cells indicate that graphene oxide could be a robust candidate for many biological fields, such as DNA and protein analysis, gene and drug delivering, and intracellular tracking.
Abstract: Graphene has shown fascinating applications in bionanotechnology, including DNA sensing, protein assays, and drug delivery. However, exploration of graphene with intracellular monitoring and in situ molecular probing is still at an early stage. In this regard, we have designed an aptamer-carboxyfluorescein (FAM)/graphene oxide nanosheet (GO-nS) nanocomplex to investigate its ability for molecular probing in living cells. Results demonstrate that uptake of aptamer-FAM/GO-nS nanocomplex and cellular target monitoring were realized successfully. The dramatic delivery, protection, and sensing capabilities of GO-nS in living cells indicate that graphene oxide could be a robust candidate for many biological fields, such as DNA and protein analysis, gene and drug delivering, and intracellular tracking.

1,025 citations


Journal ArticleDOI
TL;DR: In this paper, Nitrogen-doped graphene (N-graphene) is obtained by exposing graphene to nitrogen plasma, and it exhibits much higher electrocatalytic activity toward oxygen reduction and H2O2 reduction than graphene, and much higher durability and selectivity than the widely used expensive Pt for oxygen reduction.
Abstract: Nitrogen-doped graphene (N-graphene) is obtained by exposing graphene to nitrogen plasma. N-graphene exhibits much higher electrocatalytic activity toward oxygen reduction and H2O2 reduction than graphene, and much higher durability and selectivity than the widely-used expensive Pt for oxygen reduction. The excellent electrochemical performance of N-graphene is attributed to nitrogen functional groups and the specific properties of graphene. This indicates that N-graphene is promising for applications in electrochemical energy devices (fuel cells, metal–air batteries) and biosensors.

1,017 citations


Journal ArticleDOI
TL;DR: A series of titanium dioxide and graphene sheets composites were synthesized with a sol-gel method using tetrabutyl titanate and graphite oxide (GO) as the starting materials.
Abstract: A series of titanium dioxide and graphene sheets (GSs) composites were synthesized with a sol–gel method using tetrabutyl titanate and graphite oxide (GO) as the starting materials. The obtained TiO2/GSs photocatalysts are characterized by X-ray diffraction, N2 adsorption analysis, Raman spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy. The photocatalytic activity of the as-prepared samples was evaluated by hydrogen evolution from water photo-splitting under UV-vis illumination. The influence of GSs content and calcinations atmosphere on the photocatalytic activity was also investigated. The results show that both GSs content and the calcinations atmosphere can affect the photocatalytic activity of the obtained composites.

985 citations


Book ChapterDOI
04 Mar 2010
TL;DR: Keywords, which the authors define as a sequence of one or more words, provide a compact representation of a document’s content.
Abstract: Keywords, which we define as a sequence of one or more words, provide a compact representation of a document’s content. Ideally, keywords represent in condensed form the essential content of a document.

975 citations


Journal ArticleDOI
TL;DR: In this article, a review describes the properties of biochar and suggests possible reactions that may occur after the addition of biochars to soil, including dissolution-precipitation, adsorption-desorption, acid-base, and redox reactions.
Abstract: Interactions between biochar, soil, microbes, and plant roots may occur within a short period of time after application to the soil. The extent, rates, and implications of these interactions, however, are far from understood. This review describes the properties of biochars and suggests possible reactions that may occur after the addition of biochars to soil. These include dissolution-precipitation, adsorption-desorption, acid-base, and redox reactions. Attention is given to reactions occurring within pores, and to interactions with roots, microorganisms, and soil fauna. Examination of biochars (from chicken litter, greenwaste, and paper mill sludges) weathered for 1 and 2 years in an Australian Ferrosol provides evidence for some of the mechanisms described in this review and offers an insight to reactions at a molecular scale. These interactions are biochar- and site-specific. Therefore, suitable experimental trials—combining biochar types and different pedoclimatic conditions—are needed to determine the extent to which these reactions influence the potential of biochar as a soil amendment and tool for carbon sequestration.

Journal ArticleDOI
25 Feb 2010-ACS Nano
TL;DR: A ternary self-assembly approach using graphene as fundamental building blocks to construct ordered metal oxide-graphene nanocomposite films and electrodes is demonstrated and a new class of layered Nanocomposites is formed containing stable, ordered alternating layers of nanocrystalline metal oxides with graphene or graphene stacks.
Abstract: Surfactant or polymer directed self-assembly has been widely investigated to prepare nanostructured metal oxides, semiconductors, and polymers, but this approach is mostly limited to two-phase materials, organic/inorganic hybrids, and nanoparticle or polymer-based nanocomposites. Self-assembled nanostructures from more complex, multiscale, and multiphase building blocks have been investigated with limited success. Here, we demonstrate a ternary self-assembly approach using graphene as fundamental building blocks to construct ordered metal oxide−graphene nanocomposites. A new class of layered nanocomposites is formed containing stable, ordered alternating layers of nanocrystalline metal oxides with graphene or graphene stacks. Alternatively, the graphene or graphene stacks can be incorporated into liquid-crystal-templated nanoporous structures to form high surface area, conductive networks. The self-assembly method can also be used to fabricate free-standing, flexible metal oxide−graphene nanocomposite fil...

Journal ArticleDOI
TL;DR: The electrochemically reduced graphene oxide (ER-G) has shown promising features for applications in energy storage, biosensors, and electrocatalysis as discussed by the authors, which can be used for energy storage.
Abstract: Graphene oxide is electrochemically reduced which is called electrochemically reduced graphene oxide (ER-G). ER-G is characterized with scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The oxygen content is significantly decreased and the sp2 carbon is restored after electrochemical reduction. ER-G exhibits much higher electrochemical capacitance and cycling durability than carbon nanotubes (CNTs) and chemically reduced graphene; the specific capacitance measured with cyclic voltammetry (20 mV s−1) is ∼165, ∼86, and ∼100 F g−1 for ER-G, CNTs, and chemically reduced graphene, respectively. The electrochemical reduction of oxygen and hydrogen peroxide are greatly enhanced on ER-G electrodes as compared with CNTs. ER-G has shown promising features for applications in energy storage, biosensors, and electrocatalysis.

Journal ArticleDOI
TL;DR: In this paper, disordered nanocomposites comprised of polyethylene oxide and exfoliated MoS2 are cycled in the voltage range of 0.01−3.0 V.
Abstract: Disordered nanocomposites comprised of polyethylene oxide and exfoliated MoS2 are cycled in the voltage range of 0.01−3.0 V. The nanocomposites showed a significant increase in reversible capacity and cycle stability when compared to exfoliated or bulk MoS2 and may be used as anode material in lithium ion batteries.

Journal ArticleDOI
TL;DR: In this paper, the performance of a Cu ion-exchanged SSZ-13 zeolite in the selective catalytic reduction (SCR) of NO x with NH 3 was observed, in comparison with Cu-beta and ZSM-5 zeolites.

Journal ArticleDOI
01 Jan 2010
TL;DR: This article has given a broadbrush description of issues related to smart-grid security; in some cases solutions exist, whereas in others research investments will be needed.
Abstract: This article has given a broadbrush description of issues related to smart-grid security. Designing solutions in at this stage, before widespread deployment, would be beneficial; in some cases solutions exist, whereas in others research investments will be needed. Several open questions about goals still require discussion, especially around such topics as how (and how much) privacy can be supported.

Journal ArticleDOI
15 May 2010-Talanta
TL;DR: An electrochemical sensor based on the electrocatalytic activity of functionalized graphene for sensitive detection of paracetamol is presented and shows great promise for simple, sensitive, and quantitative detection and screening of par acetamol.

Journal ArticleDOI
TL;DR: In this paper, the authors measured an increase in CO2 production from soils after biochar amendment which increased with increasing rates of biochar, confirming that biochar contributed to the CO2 flux.
Abstract: The low temperature pyrolysis of organic material produces biochar, a charcoal like substance. Biochar is being promoted as a soil amendment to enhance soil quality, it is also seen as a mechanism of long-term sequestration of carbon. Our experiments tested the hypothesis that biochar is inert in soil. However, we measured an increase in CO2 production from soils after biochar amendment which increased with increasing rates of biochar. The ∂13C signature of the CO2 evolved in the first several days of the incubation was the same as the ∂13C signature of the biochar, confirming that biochar contributed to the CO2 flux. This effect diminished by day 6 of the incubation suggesting that most of the biochar C is slowly decomposing. Thus, aside from this short-term mineralization increasing soil C with young biochar may indeed be a long-term C storage mechanism.

Journal ArticleDOI
TL;DR: A comprehensive review on materials of electrodes and electrolytes for the Na-beta alumina batteries and discusses the challenges ahead for further technology improvement can be found in this paper, where the authors also discuss the challenges that hinders broad applications and market penetration of the technologies.

Journal ArticleDOI
TL;DR: The wood-degrading fungus Schizophyllum commune is both a genetically tractable model for studying mushroom development and a likely source of enzymes capable of efficient degradation of lignocellulosic biomass.
Abstract: Much remains to be learned about the biology of mushroom-forming fungi, which are an important source of food, secondary metabolites and industrial enzymes. The wood-degrading fungus Schizophyllum commune is both a genetically tractable model for studying mushroom development and a likely source of enzymes capable of efficient degradation of lignocellulosic biomass. Comparative analyses of its 38.5-megabase genome, which encodes 13,210 predicted genes, reveal the species's unique wood-degrading machinery. One-third of the 471 genes predicted to encode transcription factors are differentially expressed during sexual development of S. commune. Whereas inactivation of one of these, fst4, prevented mushroom formation, inactivation of another, fst3, resulted in more, albeit smaller, mushrooms than in the wild-type fungus. Antisense transcripts may also have a role in the formation of fruiting bodies. Better insight into the mechanisms underlying mushroom formation should affect commercial production of mushrooms and their industrial use for producing enzymes and pharmaceuticals.

Journal ArticleDOI
TL;DR: The SRDB database as discussed by the authors is a compendium of published soil respiration data, and is available to the scientific community both as a traditional static archive and as a dynamic community database that may be updated over time by interested users.
Abstract: . Soil respiration – RS, the flux of CO2 from the soil to the atmosphere – is probably the least well constrained component of the terrestrial carbon cycle. Here we introduce the SRDB database, a near-universal compendium of published RS data, and make it available to the scientific community both as a traditional static archive and as a dynamic community database that may be updated over time by interested users. The database encompasses all published studies that report one of the following data measured in the field (not laboratory): annual RS, mean seasonal RS, a seasonal or annual partitioning of RS into its sources fluxes, RS temperature response (Q10), or RS at 10 °C. Its orientation is thus to seasonal and annual fluxes, not shorter-term or chamber-specific measurements. To date, data from 818 studies have been entered into the database, constituting 3379 records. The data span the measurement years 1961–2007 and are dominated by temperate, well-drained forests. We briefly examine some aspects of the SRDB data – its climate space coverage, mean annual RS fluxes and their correlation with other carbon fluxes, RS variability, temperature sensitivities, and the partitioning of RS source flux – and suggest some potential lines of research that could be explored using these data. The SRDB database is available online in a permanent archive as well as via a project-hosting repository; the latter source leverages open-source software technologies to encourage wider participation in the database's future development. Ultimately, we hope that the updating of, and corrections to, the SRDB will become a shared project, managed by the users of these data in the scientific community.

Journal ArticleDOI
TL;DR: Hadoop and the MapReduce programming paradigm already have a substantial base in the bioinformatics community, especially in the field of next-generation sequencing analysis, and such use is increasing, due to the cost-effectiveness of Hadoop-based analysis on commodity Linux clusters, and in the cloud via data upload to cloud vendors who have implemented Hadooper/HBase.
Abstract: Bioinformatics researchers are now confronted with analysis of ultra large-scale data sets, a problem that will only increase at an alarming rate in coming years. Recent developments in open source software, that is, the Hadoop project and associated software, provide a foundation for scaling to petabyte scale data warehouses on Linux clusters, providing fault-tolerant parallelized analysis on such data using a programming style named MapReduce. An overview is given of the current usage within the bioinformatics community of Hadoop, a top-level Apache Software Foundation project, and of associated open source software projects. The concepts behind Hadoop and the associated HBase project are defined, and current bioinformatics software that employ Hadoop is described. The focus is on next-generation sequencing, as the leading application area to date. Hadoop and the MapReduce programming paradigm already have a substantial base in the bioinformatics community, especially in the field of next-generation sequencing analysis, and such use is increasing. This is due to the cost-effectiveness of Hadoop-based analysis on commodity Linux clusters, and in the cloud via data upload to cloud vendors who have implemented Hadoop/HBase; and due to the effectiveness and ease-of-use of the MapReduce method in parallelization of many data analysis algorithms.

Journal ArticleDOI
TL;DR: A novel electrochemical immunosensor for sensitive detection of cancer biomarker alpha-fetoprotein (AFP) is described that uses a graphene sheet sensor platform and functionalized carbon nanospheres labeled with horseradish peroxidase-secondary antibodies (HRP-Ab2) based on a dual signal amplification strategy.
Abstract: A novel electrochemical immunosensor for sensitive detection of cancer biomarker α-fetoprotein (AFP) is described that uses a graphene sheet sensor platform and functionalized carbon nanospheres (CNSs) labeled with horseradish peroxidase-secondary antibodies (HRP-Ab2). Greatly enhanced sensitivity for the cancer biomarker is based on a dual signal amplification strategy: first, the synthesized CNSs yielded a homogeneous and narrow size distribution, which allowed several binding events of HRP-Ab2 on each nanosphere. Enhanced sensitivity was achieved by introducing the multibioconjugates of HRP-Ab2-CNSs onto the electrode surface through “sandwich” immunoreactions. Second, functionalized graphene sheets used for the biosensor platform increased the surface area to capture a large amount of primary antibodies (Ab1), thus amplifying the detection response. On the basis of the dual signal amplification strategy of graphene sheets and the multienzyme labeling, the developed immunosensor showed a 7-fold increas...

Journal ArticleDOI
TL;DR: The results confirm the hypothesis that for liquid-based in vitro systems, the dose-rates and target cell doses for all particles are not equal; they can vary significantly, in direct contrast to the assumption of dose-equivalency implicit in the use of mass-based media concentrations as metrics of exposure for dose-response assessment.
Abstract: Background: The difficulty of directly measuring cellular dose is a significant obstacle to application of target tissue dosimetry for nanoparticle and microparticle toxicity assessment, particularly for in vitro systems. As a consequence, the target tissue paradigm for dosimetry and hazard assessment of nanoparticles has largely been ignored in favor of using metrics of exposure (e.g. μg particle/mL culture medium, particle surface area/mL, particle number/mL). We have developed a computational model of solution particokinetics (sedimentation, diffusion) and dosimetry for non-interacting spherical particles and their agglomerates in monolayer cell culture systems. Particle transport to cells is calculated by simultaneous solution of Stokes Law (sedimentation) and the Stokes-Einstein equation (diffusion). Results: The In vitro Sedimentation, Diffusion and Dosimetry model (ISDD) was tested against measured transport rates or cellular doses for multiple sizes of polystyrene spheres (20-1100 nm), 35 nm amorphous silica, and large agglomerates of 30 nm iron oxide particles. Overall, without adjusting any parameters, model predicted cellular doses were in close agreement with the experimental data, differing from as little as 5% to as much as three-fold, but in most cases approximately two-fold, within the limits of the accuracy of the measurement systems. Applying the model, we generalize the effects of particle size, particle density, agglomeration state and agglomerate characteristics on target cell dosimetry in vitro. Conclusions: Our results confirm our hypothesis that for liquid-based in vitro systems, the dose-rates and target cell doses for all particles are not equal; they can vary significantly, in direct contrast to the assumption of doseequivalency implicit in the use of mass-based media concentrations as metrics of exposure for dose-response assessment. The difference between equivalent nominal media concentration exposures on a μg/mL basis and target cell doses on a particle surface area or number basis can be as high as three to six orders of magnitude. As a consequence, in vitro hazard assessments utilizing mass-based exposure metrics have inherently high errors where particle number or surface areas target cells doses are believed to drive response. The gold standard for particle dosimetry for in vitro nanotoxicology studies should be direct experimental measurement of the cellular content of the studied particle. However, where such measurements are impractical, unfeasible, and before such measurements become common, particle dosimetry models such as ISDD provide a valuable, immediately useful alternative, and eventually, an adjunct to such measurements.

Journal ArticleDOI
TL;DR: In this paper, a process-based treatment of ice supersaturation and ice nucleation is implemented in the National Center for Atmospheric Research Community Atmosphere Model (CAM), which is able to reproduce field observations of ice mass and mixed phase cloud occurrence better than previous versions.
Abstract: [1] A process-based treatment of ice supersaturation and ice nucleation is implemented in the National Center for Atmospheric Research Community Atmosphere Model (CAM). The new scheme is designed to allow (1) supersaturation with respect to ice, (2) ice nucleation by aerosol particles, and (3) ice cloud cover consistent with ice microphysics. The scheme is implemented with a two-moment microphysics code and is used to evaluate ice cloud nucleation mechanisms and supersaturation in CAM. The new model is able to reproduce field observations of ice mass and mixed phase cloud occurrence better than previous versions. The model is able to reproduce observed patterns and frequency of ice supersaturation. Simulations indicate homogeneous freezing of sulfate and heterogeneous freezing on dust are both important ice nucleation mechanisms, in different regions. Simulated cloud forcing and climate is sensitive to different formulations of the ice microphysics. Arctic surface radiative fluxes are sensitive to the parameterization of ice clouds. These results indicate that ice clouds are potentially an important part of understanding cloud forcing and potential cloud feedbacks, particularly in the Arctic.

Journal ArticleDOI
16 Aug 2010-Analyst
TL;DR: Nanospray desorption electrospray ionization (nano-DESI) mass spectrometry is presented as an ambient pressure liquid extraction-ionization technique for analysis of organic and biological molecules on substrates and its potential for imaging applications is discussed.
Abstract: Nanospray desorption electrospray ionization (nano-DESI) mass spectrometry is presented as an ambient pressure liquid extraction-ionization technique for analysis of organic and biological molecules on substrates. Analyte is desorbed into a solvent bridge formed between two capillaries and the analysis surface. One capillary supplies solvent to create and maintain the bridge, while the second capillary transports the dissolved analyte from the bridge to the mass spectrometer. A high voltage applied between the inlet of mass spectrometer and the primary capillary creates a self-aspirating nanospray. This approach enables the separation of desorption and ionization events, thus providing independent control of desorption, ionization, and transport of the analyte. We present analytical capabilities of the method and discuss its potential for imaging applications.

Journal ArticleDOI
TL;DR: In this paper, the advantages of both single-layer graphene and highly graphitic carbon were reported as a durable alternative support material for Pt nanoparticles for oxygen reduction in fuel cells.

Journal ArticleDOI
TL;DR: In this paper, the authors performed proteomic and lipidomic profiling over a time course of acute hepatitis C virus (HCV) infection in cultured Huh-7.5 cells to gain new insights into the intracellular processes influenced by this virus.
Abstract: Proteomic and lipidomic profiling was performed over a time course of acute hepatitis C virus (HCV) infection in cultured Huh-7.5 cells to gain new insights into the intracellular processes influenced by this virus. Our proteomic data suggest that HCV induces early perturbations in glycolysis, the pentose phosphate pathway, and the citric acid cycle, which favor host biosynthetic activities supporting viral replication and propagation. This is followed by a compensatory shift in metabolism aimed at maintaining energy homeostasis and cell viability during elevated viral replication and increasing cellular stress. Complementary lipidomic analyses identified numerous temporal perturbations in select lipid species (e.g. phospholipids and sphingomyelins) predicted to play important roles in viral replication and downstream assembly and secretion events. The elevation of lipotoxic ceramide species suggests a potential link between HCV-associated biochemical alterations and the direct cytopathic effect observed in this in vitro system. Using innovative computational modeling approaches, we further identified mitochondrial fatty acid oxidation enzymes, which are comparably regulated during in vitro infection and in patients with histological evidence of fibrosis, as possible targets through which HCV regulates temporal alterations in cellular metabolic homeostasis.

Journal ArticleDOI
TL;DR: The results demonstrate that the quantum dot-based lateral flow test strip is capable of rapid, sensitive, and quantitative detection of nitrated ceruloplasmin and hold a great promise for point-of-care and in field analysis of other protein biomarkers.
Abstract: A portable fluorescence biosensor with rapid and ultrasensitive response for protein biomarker has been built up with quantum dots and a lateral flow test strip. The superior signal brightness and high photostability of quantum dots are combined with the promising advantages of a lateral flow test strip and result in high sensitivity and selectivity and speed for protein detection. Nitrated ceruloplasmin, a significant biomarker for cardiovascular disease, lung cancer, and stress response to smoking, was used as model protein biomarker to demonstrate the good performances of this proposed quantum dot-based lateral flow test strip. Quantitative detection of nitrated ceruloplasmin was realized by recording the fluorescence intensity of quantum dots captured on the test line. Under optimal conditions, this portable fluorescence biosensor displays rapid responses for nitrated ceruloplasmin with the concentration as low as 1 ng/mL. Furthermore, the biosensor was successfully utilized for spiked human plasma sa...

BookDOI
27 Aug 2010
TL;DR: In this paper, the authors discuss the role of catalysts in catalytic reduction of molecular Nitrogen Interconversion of Mo(NH3) and Mo(N2) using the second coordination sphere to control the movement of Protons between the metal and the exterior of the molecular catalysts.
Abstract: Preface CATALYSIS INVOLVING THE H*TRANSFER REACTIONS OF FIRST-ROW TRANSITION METALS H*Transfer Between M-H Bonds and Organic Radicals H*Transfer Between Ligands and Organic Radicals H*Transfer Between M-H and C-C Bonds Chain Transfer Catalysis Catalysis of Radical Cyclizations Competing Methods for the Cyclization of Dienes Summary and Conclusions CATALYYTIC REDUCTION OF DINITROGEN TO AMMONIA BY MOLYBDENUM Introduction Some Characteristics of Triamidoamine Complexes Possible [HIPTN3N]Mo Intermediates in a Catalytic Reduction of Molecular Nitrogen Interconversion of Mo(NH3) and Mo(N2) Catalytic Reduction of Dinitrogen MoH and Mo(H2) Ligand and Metal Variations Comments MOLYBDENUM AND TUNGSTEN CATALYSTS FOR HYDROGENATION, HYDROSILYLATION AND HYDROLYSIS Introduction Proton Transfer Reactions of Metal Hydrides Hydride Transfer Reactdions of Metal Hydrides Stoichiometric Hydride Transfer Reactivity of Anionic Metal Hydride Complexes Catalytic Hydrogenation of Ketones with Anionic Metal Hydrides Ionic Hydrogenation of Ketones Using Metal Hydrides and Added Acid Ionic Hydrogenations from Dihydrides: Delivery of the Proton and Hydride from One Metal Catalytic Ionic Hydrogenations With Mo and W Catalysts Mo Phosphine Catalysts With Improved Lifetimes Tungsten Hydrogenation Catalysts with N-Heterocyclic Carbene Ligands Catalysts for Hydrosilylation of Ketones Cp2Mo Catalysts for Hydrolysis, Hydrogenations and Hydrations Conclusion MODERN ALCHEMY: REPLACING PRECIOUS METALS WITH IRON IN CATALYTIC ALKENE AND CARBONYL HYDROGENATION REACTIONS Introduction Alkene Hydrogenation Carbonyl Hydrogenation Outlook OLEFIN OOLIGOMERIZATIONS AND POLYMERIZATIONS CATALYZED BY IRON AND COBALT COMPLEXES BEARING BIS(IMINO)PYRIDINE LIGANDS Introduction Precatalyst Synthesis Precatalyst Activation and Catalysis The Active Catalyst and Mechanism Other Applications Conclusions and Outlook COBALT AND NICKEL CATALYZED REACTIONS INVOLVING C-H AND C-N ACTIVATION REACTIONS Introduction Catalysis with Cobalt Catalysis with Nickel A MODULAR APPROACH TO THE DEVELOPMENT OF MOLECULAR ELECTROCATALYSTS FOR H2 OXIDATION AND PRODUCTION BASED ON INEXPENSIVE METALS Introduction Concepts in Catalyst Design Based on Structural Studies of Hydrogenase Enzymes A Layered or Modular Approach to Catalyst Design Using the First Coordination Sphere to Control the Energies of Catalytic Intermediates Using the Second Coordination Sphere to Control the Movement of Protons between the Metal and the Exterior of the Molecular Catalyst Integration of the First and Second Coordination Spheres Summary NICKEL-CATALYZED REDUCTIVE COUPLINGS AND CYCLIZATIONS Introduction Couplings of Alkynes with alpha, beta-Unsaturated Carbonyls Couplings of Alkynes with Aldehydes Conclusions and Outlook COPPER-CATALYZED LIGAND PROMOTED ULLMANN-TYPE COUPLING REACTIONS Introduction C-N Bond Formation C-O Bond Formation C-C Bond Formation C-S Bond Formation C-P Bond Formation Conclusion COPPER-CATALYZED LIGAND PROMOTED ULLMANN-TYPE COUPLING REACTIONS Introduction C-N Bond Formation C-O Bond Formation C-C Bond Formation C-S Bond Formation C-P Bond Formation Conclusion COPPER-CATALYZED AZIDE-ALKYNE CYCLOADDITION (CuAAC) Introduction Azide-Alkyne Cycloaddition: Basics Copper-Catalyzed Cycloadditions "FRUSTRATED LEWIS PAIRS": A METAL-FREE STRATEGY FOR HYDROGENATION CATALYSIS Phosphine-Borane Activation of H2 "Frustrated Lewis Pairs" Metal-Free Catalytic Hydrogenation Future Considerations