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Sample records for site-specific ion desorption

  1. Surface Electronic Properties and Site-Specific Laser Desorption Processes of Highly Structured Nanoporous MgO Thin Films

    SciTech Connect

    Henyk, Matthias; Beck, Kenneth M.; Engelhard, Mark H.; Joly, Alan G.; Hess, Wayne P.; Dickinson, J T.

    2005-11-20

    O films, we find that the laser fluence required for oxygen desorption is much lower in comparison to the single-crystal MgO (100) surface. The detected neutral oxygen desorption occurs with a single photon power dependence from nanoporous MgO thin films. This contrasts to the two-photon power dependence observed from MgO single crystals. In fact, the single photon energy of the laser lies within the charge-transfer transition in surface ion pairs with three-coordinated anions ({approx} 4.7 eV), while a two-photon absorption regime easily lies within the four-coordinated anion charge transfer transition near 5.4 eV [3]. In summary, our XPS studies and laser desorption experiments indicate new surface-site-specific excitation regimes, which might eventually allow for site-specific manipulation of surface morphology.

  2. Site-Specific Fragmentation of Polystyrene Molecule Using Size-Selected Ar Gas Cluster Ion Beam

    NASA Astrophysics Data System (ADS)

    Moritani, Kousuke; Mukai, Gen; Hashinokuchi, Michihiro; Mochiji, Kozo

    2009-04-01

    The secondary ion mass spectrum (SIMS) of a polystyrene thin film was investigated using a size-selected Ar gas cluster ion beam (GCIB). The fragmentation in the SIM spectrum varied by kinetic energy per atom (Eatom); the Eatom dependence of the secondary ion intensity of the fragment species of polystyrene can be essentially classified into three types based on the relationship between Eatom and the dissociation energy of a specific bonding site in the molecule. These results indicate that adjusting Eatom of size-selected GCIB may realize site-specific bond breaking within a molecule.

  3. Site-Specific Mapping of Sialic Acid Linkage Isomers by Ion Mobility Spectrometry.

    PubMed

    Guttman, Miklos; Lee, Kelly K

    2016-05-17

    Detailed structural elucidation of protein glycosylation is a tedious process often involving several techniques. Glycomics and glycoproteomics approaches with mass spectrometry offer a rapid platform for glycan profiling but are limited by the inability to resolve isobaric species such as linkage and positional isomers. Recently, ion mobility spectrometry (IMS) has been shown to effectively resolve isobaric oligosaccharides, but the utility of IMS to obtain glycan structural information on a site-specific level with proteomic analyses has yet to be investigated. Here, we report that the addition of IMS to conventional glycoproteomics platforms adds additional information regarding glycan structure and is particularly useful for differentiation of sialic acid linkage isomers on both N- and O-linked glycopeptides. With further development IMS may hold the potential for rapid and complete structural elucidation of glycan chains at a site-specific level. PMID:27089023

  4. Site-Specific Characterization of d-Amino Acid Containing Peptide Epimers by Ion Mobility Spectrometry

    PubMed Central

    2013-01-01

    Traditionally, the d-amino acid containing peptide (DAACP) candidate can be discovered by observing the differences of biological activity and chromatographic retention time between the synthetic peptides and naturally occurring peptides. However, it is difficult to determine the exact position of d-amino acid in the DAACP candidates. Herein, we developed a novel site-specific strategy to rapidly and precisely localize d-amino acids in peptides by ion mobility spectrometry (IMS) analysis of mass spectrometry (MS)-generated epimeric fragment ions. Briefly, the d/l-peptide epimers were separated by online reversed-phase liquid chromatography and fragmented by collision-induced dissociation (CID), followed by IMS analysis. The epimeric fragment ions resulting from d/l-peptide epimers exhibit conformational differences, thus showing different mobilities in IMS. The arrival time shift between the epimeric fragment ions was used as criteria to localize the d-amino acid substitution. The utility of this strategy was demonstrated by analysis of peptide epimers with different molecular sizes, [d-Trp]-melanocyte-stimulating hormone, [d-Ala]-deltorphin, [d-Phe]-achatin-I, and their counterparts that contain all-l amino acids. Furthermore, the crustacean hyperglycemia hormones (CHHs, 8.5 kDa) were isolated from the American lobster Homarus americanus and identified by integration of MS-based bottom-up and top-down sequencing approaches. The IMS data acquired using our novel site-specific strategy localized the site of isomerization of l- to d-Phe at the third residue of the CHHs from the N-terminus. Collectively, this study demonstrates a new method for discovery of DAACPs using IMS technique with the ability to localize d-amino acid residues. PMID:24328107

  5. Integrated field emission array for ion desorption

    DOEpatents

    Resnick, Paul J; Hertz, Kristin L; Holland, Christopher; Chichester, David; Schwoebel, Paul

    2013-09-17

    An integrated field emission array for ion desorption includes an electrically conductive substrate; a dielectric layer lying over the electrically conductive substrate comprising a plurality of laterally separated cavities extending through the dielectric layer; a like plurality of conically-shaped emitter tips on posts, each emitter tip/post disposed concentrically within a laterally separated cavity and electrically contacting the substrate; and a gate electrode structure lying over the dielectric layer, including a like plurality of circular gate apertures, each gate aperture disposed concentrically above an emitter tip/post to provide a like plurality of annular gate electrodes and wherein the lower edge of each annular gate electrode proximate the like emitter tip/post is rounded. Also disclosed herein are methods for fabricating an integrated field emission array.

  6. Integrated field emission array for ion desorption

    DOEpatents

    Resnick, Paul J; Hertz, Kristin L.; Holland, Christopher; Chichester, David

    2016-08-23

    An integrated field emission array for ion desorption includes an electrically conductive substrate; a dielectric layer lying over the electrically conductive substrate comprising a plurality of laterally separated cavities extending through the dielectric layer; a like plurality of conically-shaped emitter tips on posts, each emitter tip/post disposed concentrically within a laterally separated cavity and electrically contacting the substrate; and a gate electrode structure lying over the dielectric layer, including a like plurality of circular gate apertures, each gate aperture disposed concentrically above an emitter tip/post to provide a like plurality of annular gate electrodes and wherein the lower edge of each annular gate electrode proximate the like emitter tip/post is rounded. Also disclosed herein are methods for fabricating an integrated field emission array.

  7. Heavy-ion induced electronic desorption of gas from metals

    SciTech Connect

    Molvik, A W; Kollmus, H; Mahner, E; Covo, M K; Bellachioma, M C; Bender, M; Bieniosek, F M; Hedlund, E; Kramer, A; Kwan, J; Malyshev, O B; Prost, L; Seidl, P A; Westenskow, G; Westerberg, L

    2006-12-19

    During heavy ion operation in several particle accelerators world-wide, dynamic pressure rises of orders of magnitude were triggered by lost beam ions that bombarded the vacuum chamber walls. This ion-induced molecular desorption, observed at CERN, GSI, and BNL, can seriously limit the ion beam lifetime and intensity of the accelerator. From dedicated test stand experiments we have discovered that heavy-ion induced gas desorption scales with the electronic energy loss (dE{sub e}/d/dx) of the ions slowing down in matter; but it varies only little with the ion impact angle, unlike electronic sputtering.

  8. Site-specific specimen preparation by focused ion beam milling for transmission electron microscopy of metal matrix composites.

    PubMed

    Gasser, Philippe; Klotz, Ulrich E; Khalid, Fazal A; Beffort, Olivier

    2004-04-01

    This work describes the application and usefulness of the focused ion beam (FIB) technique for the preparation of transmission electron microscopy (TEM) samples from metal matrix composite materials. Results on an Aldiamond composite, manufactured by the squeeze casting infiltration process, were chosen for demonstration. It is almost impossible to prepare TEM specimens of this material by any other conventional method owing to the presence of highly inhomogeneous phases and reinforcement diamond particles. The present article gives a detailed account of the salient features of the FIB technique and its operation. One of the big advantages is the possibility to prepare site-specific TEM specimens with high spatial resolution. The artifacts occurring during the specimen preparation, for example, Ga-ion implantation, curtain effects, amorphous layers, bending of the lamella, or different milling behaviors of the materials have been discussed. Furthermore, TEM examination of the specimens prepared revealed an ultrafine amorphous layer of graphite formed at the interface between the Al and diamond particles that may affect the interfacial properties of the composite materials. This may not have been feasible without the successful application of the FIB technique for production of good quality site-specific TEM specimens. PMID:15306057

  9. Site-Specific Cryo-focused Ion Beam Sample Preparation Guided by 3D Correlative Microscopy.

    PubMed

    Arnold, Jan; Mahamid, Julia; Lucic, Vladan; de Marco, Alex; Fernandez, Jose-Jesus; Laugks, Tim; Mayer, Tobias; Hyman, Anthony A; Baumeister, Wolfgang; Plitzko, Jürgen M

    2016-02-23

    The development of cryo-focused ion beam (cryo-FIB) for the thinning of frozen-hydrated biological specimens enabled cryo-electron tomography (cryo-ET) analysis in unperturbed cells and tissues. However, the volume represented within a typical FIB lamella constitutes a small fraction of the biological specimen. Retaining low-abundance and dynamic subcellular structures or macromolecular assemblies within such limited volumes requires precise targeting of the FIB milling process. In this study, we present the development of a cryo-stage allowing for spinning-disk confocal light microscopy at cryogenic temperatures and describe the incorporation of the new hardware into existing workflows for cellular sample preparation by cryo-FIB. Introduction of fiducial markers and subsequent computation of three-dimensional coordinate transformations provide correlation between light microscopy and scanning electron microscopy/FIB. The correlative approach is employed to guide the FIB milling process of vitrified cellular samples and to capture specific structures, namely fluorescently labeled lipid droplets, in lamellas that are 300 nm thick. The correlation procedure is then applied to localize the fluorescently labeled structures in the transmission electron microscopy image of the lamella. This approach can be employed to navigate the acquisition of cryo-ET data within FIB-lamellas at specific locations, unambiguously identified by fluorescence microscopy. PMID:26769364

  10. Ion Desorption Stability in Superconducting High Energy Physics Proton Colliders

    SciTech Connect

    Turner, W.C.

    1995-05-29

    In this paper we extend our previous analysis of cold beam tube vacuum in a superconducting proton collider to include ion desorption in addition to thermal desorption and synchrotron radiation induced photodesorption. The new ion desorption terms introduce the possibility of vacuum instability. This is similar to the classical room temperature case but now modified by the inclusion of ion desorption coefficients for cryosorbed (physisorbed) molecules which can greatly exceed the coefficients for tightly bound molecules. The sojourn time concept for physisorbed H{sub 2} is generalized to include photodesorption and ion desorption as well as the usually considered thermal desorption. The ion desorption rate is density dependent and divergent so at the onset of instability the sojourn time goes to zero. Experimental data are used to evaluate the H{sub 2} sojourn time for the conditions of the Large Hadron Collider (LHC) and the situation is found to be stable. The sojourn time is dominated by photodesorption for surface density s(H{sub 2}) less than a monolayer and by thermal deposition for s(H{sub 2}) greater than a monolayer. For a few percent of a monolayer, characteristic of a beam screen, the photodesorption rate exceeds ion desorption rate by more than two orders of magnitude. The photodesorption rate corresponds to a sojourn time of approximately 100 sec. The paper next turns to the evaluation of stability margins and inclusion of gases heavier than H{sub 2} (CO, CO{sub 2} and CH{sub 4}), where ion desorption introduces coupling between molecular species. Stability conditions are worked out for a simple cold beam tube, a cold beam tube pumped from the ends and a cold beam tube with a co-axial perforated beam screen. In each case a simple inequality for stability of a single component is replaced by a determinant that must be greater than zero for a gas mixture. The connection with the general theory of feedback stability is made and it is shown that the gains

  11. Increasing ion sorption and desorption rates of conductive electrodes

    SciTech Connect

    DePaoli, David William; Kiggans, Jr., James O; Tsouris, Costas; Bourcier, William; Campbell, Robert; Mayes, Richard T

    2014-12-30

    An electrolyte system includes a reactor having a pair of electrodes that may sorb ions from an electrolyte. The electrolyte system also includes at least one power supply in electrical communication with the reactor. The at least one power supply may supply a DC signal and an AC signal to the pair of electrodes during sorption of the ions. In addition, the power supply may supply only the AC signal to the pair of electrodes during desorption of the ions.

  12. Ambient pressure laser desorption and laser-induced acoustic desorption ion mobility spectrometry detection of explosives.

    PubMed

    Ehlert, Sven; Walte, Andreas; Zimmermann, Ralf

    2013-11-19

    The development of fast, mobile, and sensitive detection systems for security-relevant substances is of enormous importance. Because of the low vapor pressures of explosives and improvised explosive devices, adequate sampling procedures are crucial. Ion mobility spectrometers (IMSs) are fast and sensitive instruments that are used as detection systems for explosives. Ambient pressure laser desorption (APLD) and ambient pressure laser-induced acoustic desorption (AP-LIAD) are new tools suitable to evaporate explosives in order to detect them in the vapor phase. Indeed, the most important advantage of APLD or AP-LIAD is the capability to sample directly from the surface of interest without any transfer of the analyte to other surfaces such as wipe pads. A much more gentle desorption, compared to classical thermal-based desorption, is possible with laser-based desorption using very short laser pulses. With this approach the analyte molecules are evaporated in a very fast process, comparable to a shock wave. The thermal intake is reduced considerably. The functionality of APLD and AP-LIAD techniques combined with a hand-held IMS system is shown for a wide range of common explosives such as EGDN (ethylene glycol dinitrate), urea nitrate, PETN (pentaerythritol tetranitrate), HMTD (hexamethylene triperoxide diamine), RDX (hexogen), tetryl (2,4,6-trinitrophenylmethylnitramine), and TNT (trinitrotoluene). Detection limits down to the low nanogram range are obtained. The successful combination of IMS detection and APLD/AP-LIAD sampling is shown. PMID:24116702

  13. Laser desorption in an ion trap mass spectrometer

    SciTech Connect

    Eiden, G.C.; Cisper, M.E.; Alexander, M.L.; Hemberger, P.H.; Nogar, N.S.

    1993-02-01

    Laser desorption in a ion-trap mass spectrometer shows significant promise for both qualitative and trace analysis. Several aspects of this methodology are discussed in this work. We previously demonstrated the generation of both negative and positive ions by laser desorption directly within a quadrupole ion trap. In the present work, we explore various combinations of d.c., r.f., and time-varying fields in order to optimize laser generated signals. In addition, we report on the application of this method to analyze samples containing compounds such as amines, metal complexes, carbon clusters, and polynuclear aromatic hydrocarbons. In some cases the ability to rapidly switch between positive and negative ion modes provides sufficient specificity to distinguish different compounds of a mixture with a single stage of mass spectrometry. In other experiments, we combined intensity variation studies with tandem mass spectrometry experiments and positive and negative ion detection to further enhance specificity.

  14. Desorption yield for valine as induced by fast heavy ions

    SciTech Connect

    Beining, P.; Scheer, J.; Nieschler, E.; Nees, B.; Voit, H.

    1988-11-01

    The dependence of the desorption yield for the amino acid valine on the energy of different MeV primary ions has been measured. The primary-ion energies cover a relatively large range with corresponding energy losses between 2 and 55 keV/(..mu..g/cm/sup 2/). The observed energy dependence can be understood in the framework of a simple macroscopic model.

  15. Laser desorption lamp ionization source for ion trap mass spectrometry.

    PubMed

    Wu, Qinghao; Zare, Richard N

    2015-01-01

    A two-step laser desorption lamp ionization source coupled to an ion trap mass spectrometer (LDLI-ITMS) has been constructed and characterized. The pulsed infrared (IR) output of an Nd:YAG laser (1064 nm) is directed to a target inside a chamber evacuated to ~15 Pa causing desorption of molecules from the target's surface. The desorbed molecules are ionized by a vacuum ultraviolet (VUV) lamp (filled with xenon, major wavelength at 148 nm). The resulting ions are stored and detected in a three-dimensional quadrupole ion trap modified from a Finnigan Mat LCQ mass spectrometer operated at a pressure of ≥ 0.004 Pa. The limit of detection for desorbed coronene molecules is 1.5 pmol, which is about two orders of magnitude more sensitive than laser desorption laser ionization mass spectrometry using a fluorine excimer laser (157 nm) as the ionization source. The mass spectrum of four standard aromatic compounds (pyrene, coronene, rubrene and 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine (OPC)) shows that parent ions dominate. By increasing the infrared laser power, this instrument is capable of detecting inorganic compounds. PMID:25601688

  16. A Microarray-Matrix-assisted Laser Desorption/Ionization-Mass Spectrometry Approach for Site-specific Protein N-glycosylation Analysis, as Demonstrated for Human Serum Immunoglobulin M (IgM)*

    PubMed Central

    Pabst, Martin; Küster, Simon Karl; Wahl, Fabian; Krismer, Jasmin; Dittrich, Petra S.; Zenobi, Renato

    2015-01-01

    We demonstrate a new approach for the site-specific identification and characterization of protein N-glycosylation. It is based on a nano-liquid chromatography microarray-matrix assisted laser desorption/ionization-MS platform, which employs droplet microfluidics for on-plate nanoliter reactions. A chromatographic separation of a proteolytic digest is deposited at a high frequency on the microarray. In this way, a short separation run is archived into thousands of nanoliter reaction cavities, and chromatographic peaks are spread over multiple array spots. After fractionation, each other spot is treated with PNGaseF to generate two correlated traces within one run, one with treated spots where glycans are enzymatically released from the peptides, and one containing the intact glycopeptides. Mining for distinct glycosites is performed by searching for the predicted deglycosylated peptides in the treated trace. An identified peptide then leads directly to the position of the “intact” glycopeptide clusters, which are located in the adjacent spots. Furthermore, the deglycosylated peptide can be sequenced efficiently in a simple collision-induced dissociation-MS experiment. We applied the microarray approach to a detailed site-specific glycosylation analysis of human serum IgM. By scanning the treated spots with low-resolution matrix assisted laser desorption/ionization-time-of-flight-MS, we observed all five deglycosylated peptides, including the one originating from the secretory chain. A detailed glycopeptide characterization was then accomplished on the adjacent, untreated spots with high mass resolution and high mass accuracy using a matrix assisted laser desorption ionization-Fourier transform-MS. We present the first detailed and comprehensive mass spectrometric analysis on the glycopeptide level for human polyclonal IgM with high mass accuracy. Besides complex type glycans on Asn 395, 332, 171, and on the J chain, we observed oligomannosidic glycans on Asn

  17. Prompt Gas Desorption Due to Ion Impact on Accelerator Structures

    NASA Astrophysics Data System (ADS)

    Vijay, Sagar; Seidl, Peter A.; Faltens, Andy; Lidia, Steven M.

    2011-10-01

    The repetition rate and peak current of high intensity ion accelerators for inertial fusion or other applications may be limited under certain conditions by the desorption of gas molecules and atoms due to stray ions striking the accelerator structure. We have measured the prompt yield of atoms in close proximity to the point of impact of the ions on a surface. Using the 300-keV, K+ ion beam of the Neutralized Drift Compression Experiment (NDCX-I), ions strike a metal target in a 5-10 microsecond bunch. The collector of a Bayert-Alpert style ionization gauge is used to detect the local pressure burst several centimeters away. Pressure transients are observed on a micro-second time scale due to the initial burst of desorbed gas, and on a much longer (~1 second) timescale, corresponding to the equilibration of the pressure after many ``bounces'' of atoms in the vacuum chamber. We report on these time dependent pressure measurements, modeling of the pressure transient, and implications for high-intensity ion accelerators. Work performed under auspices of U.S. DOE by LBNL under Contract DE-AC02-05CH1123.

  18. Auger Stimulated Ion Desorption of Negative Ions via K -Capture Radioactive Decay

    SciTech Connect

    Verkhoturov, S. V.; Schweikert, E. A.; Chechik, Victor; Sabapathy, Rajaram C.; Crooks, Richard M.; Parilis, E. S.

    2001-07-16

    We report on Auger stimulated ion desorption via Coulomb explosion from surface self-assembled alkylthiol and fluorocarbon molecular layers, triggered by K -capture decay of an imbedded radioactive {sup 55}Fe atom. The charge state of the ejecta is determined by charge exchange in binary atomic collisions in bulk and electron tunneling outside the solid, as well as by fragmentation of electronically excited molecules or molecular fragments. We describe the first nonbeam experiments documenting positive and abundant negative ion desorption due solely to core electron excitation after radioactive decay.

  19. Site specific isolated nanostructure array formation on a large area by broad ion beam without any mask and resist

    NASA Astrophysics Data System (ADS)

    Karmakar, Prasanta; Satpati, Biswarup

    2014-06-01

    We report the formation of isolated nanostructure arrays on a large area via broad ion beam implantation without the aid of any mask or resist. Desired ions have been implanted at specific locations of the prefabricated silicon ripple or triangular structures by exploiting the variation of local ion impact angles. We have shown that the implantation of Fe ions on an O+ ions induced pre fabricated triangular shaped patterned Si surface results in a self-organized periodic array of striped magnetic nanostructures having several micron length and about 50 nm width arranged with a spacial separation of ˜200 nm. The morphology, composition, crystalline structure, and magnetic property of these nanopatterns have been analyzed using high-resolution cross-sectional transmission electron microscopy and atomic force microscopy. A geometrical model has been proposed to explain the fundamental features of such ion-induced nanopattern structures.

  20. Auger decay mechanism in photon-stimulated desorption of ions from surfaces

    SciTech Connect

    Parks, C.C.

    1983-11-01

    Photon-stimulated desorption (PSD) of positive ions was studied with synchrotron radiation using an angle-integrating time-of-flight mass spectrometer. Ion yields as functions of photon energy near core levels were measured from condensed gases, alkali fluorides, and other alkali and alkaline earth halides. These results are compared to bulk photoabsorption measurements with emphasis on understanding fundamental desorption mechanisms. The applicability of the Auger decay mechanism, in which ion desorption is strictly proportional to surface absorption, is discussed in detail. The Auger decay model is developed in detail to describe Na/sup +/ and F/sup +/ desorption from NaF following Na(1s) excitation. The major decay pathways of the Na(1s) hole leading to desorption are described and equations for the energetics of ion desorption are developed. Ion desorption spectra of H/sup +/, Li/sup +/, and F/sup +/ are compared to bulk photoabsorption near the F(2s) and Li(1s) edges of LiF. A strong photon beam exposure dependence of ion yields from alkali fluorides is revealed, which may indicate the predominance of metal ion desorption from defect sites. The large role of indirect mechanisms in ion desorption condensed N/sub 2/-O/sub 2/ multilayers is demonstrated and discussed. Ion desorption spectra from several alkali halides and alkaline earth halides are compared to bulk photoabsorption spectra. Relative ion yields from BaF/sub 2/ and a series of alkali halides are discussed in terms of desorption mechanisms.

  1. Carbon dioxide ion dissociations after inner shell excitation and ionization: The origin of site-specific effects

    SciTech Connect

    Eland, J. H. D.; Zagorodskikh, S.; Mucke, M.; Squibb, R. J.; Feifel, R.; Sorensen, S. L.

    2014-05-14

    Multi-coincidence experiments with detection of both electrons and ions from decay of core-excited and core-ionized states of CO{sub 2} confirm that O{sub 2}{sup +} is formed specifically in Auger decay from the C1s-π* and O1s-π* resonances. Molecular rearrangement occurs by bending in the resonant states, and O{sub 2}{sup +} is produced by both single and double Auger decay. It is suggested that electron capture by C{sup +} after partial dissociation in the doubly ionized core of excited CO{sub 2}{sup +}, formed by shake-up in spectator resonant Auger decay, accounts for high kinetic energy and high internal energy in some C + O{sub 2}{sup +} fragments.

  2. Cytoxicity of vitamin C and metal ions: a site-specific Fenton mechanism. Progress report, July 1981-June 1982

    SciTech Connect

    Samuni, A.; Aronovitch, J.; Godinger, D.; Chevion, M.; Czapski, G.

    1982-01-01

    The toxicity of ascorbate toward phages T2 through T7 has been investigated. The T-odd bacteriophages are highly susceptible to ascorbate-induced damage, whereas the t-even phages are practically resistant. The toxicity of ascorbate is dependent on the presence of copper (or iron) ions and on oxygen. The dependence on oxygen does not exist in the presence of hydrogen perioxide. Hydrogen peroxide enhances the damage and is essential for the ascorbate induced biological damage, as catalase fully protects the phages. Chelating agents such as salicylate or 1,10-phenanthroline do not prevent the damage, though they reduce the rate of phage inactivation roughly 5-fold. By contrast, EDTA or histidine fully protect the phages. OH-scavengers such as sucrose, formate, mannitol, t-BuOH or polyethylene glycol do not protect. Experiments with isotopically labeled DNA indicate that both phage adsorption to the host and the injection of its DNA are impaired as a result of the exposure to ascorbate and copper. It is also possible that some failure to express the viral genetic information contributes towards the loss of phage PFA.

  3. Gas Desorption and Electron Emission from 1 MeV Potassium Ion Bombardment of Stainless Steel

    SciTech Connect

    Molvik, A W; Covo, M K; Bieniosek, F M; Prost, L; Seidl, P A; Baca, D; Coorey, A; Sakumi, A

    2004-07-19

    Gas desorption and electron emission coefficients were measured for 1 MeV potassium ions incident on stainless steel at grazing angles (between 80 and 88 from normal incidence) using a new gas-electron source diagnostic (GESD). Issues addressed in design and commissioning of the GESD include effects from backscattering of ions at the surface, space-charge limited emission current, and reproducibility of desorption measurements. We find that electron emission coefficients {gamma}{sub e} scale as 1/cos({theta}) up to angles of 86, where {gamma}{sub e} = 90. Nearer grazing incidence, {gamma}{sub e} is reduced below the 1/cos({theta}) scaling by nuclear scattering of ions through large angles, reaching {gamma}{sub e} = 135 at 88. Electrons were emitted with a measured temperature of {approx}30 eV. Gas desorption coefficients {gamma}{sub sigma} were much larger, of order {gamma}{sub sigma} = 104. They also varied with angle, but much more slowly than 1/cos({theta}). From this we conclude that the desorption was not entirely from adsorbed layers of gas on the surface. Two mitigation techniques were investigated: rough surfaces reduced electron emission by a factor of ten and gas desorption by a factor of two; a mild bake to 230 had no effect on electron emission, but decreased gas desorption by 15% near grazing incidence. We propose that gas desorption is due to electronic sputtering.

  4. Polarization dependent fragmentation of ions produced by laser desorption from nanopost arrays.

    PubMed

    Stolee, Jessica A; Vertes, Akos

    2011-05-28

    Tailored silicon nanopost arrays (NAPA) enable controlled and resonant ion production in laser desorption ionization experiments and have been termed nanophotonic ion sources (Walker et al., J. Phys. Chem. C, 2010, 114, 4835-4840). As the post dimensions are comparable to or smaller than the laser wavelength, near-field effects and localized electromagnetic fields are present in their vicinity. In this contribution, we explore the desorption and ionization mechanism by studying how surface derivatization affects ion yields and fragmentation. We demonstrate that by increasing the laser fluence on derivatized NAPA with less polar surfaces that have decreased interaction energy between the structured silicon substrate and the adsorbate, the spectrum changes from exhibiting primarily molecular ions to showing a growing variety and abundance of fragments. The polarization angle of the laser beam had been shown to dramatically affect the ion yields of adsorbates. For the first time, we report that by rotating the plane of polarization of the desorption laser, the internal energy of the adsorbate can also be modulated resulting in polarization dependent fragmentation. This polarization effect also resulted in selective fragmentation of vitamin B(12). To explore the internal energy of NAPA generated ions, the effect of the post aspect ratios on the laser desorption thresholds and on the internal energy of a preformed ion was studied. Elevated surface temperatures and enhanced near fields in the vicinity of high aspect ratio posts are thought to contribute to desorption and ionization from NAPA. Comparison of the fluence dependence of the internal energies of ions produced from nanoporous silicon and NAPA substrates indicates that surface restructuring or transient melting by the desorption laser is a prerequisite for the former but not for the latter. PMID:21437297

  5. Electron stimulated desorption of negative ions: A time-of-flight experiment

    NASA Astrophysics Data System (ADS)

    Goeden, C.; Dollinger, G.

    2002-08-01

    We present a setup for stimulated desorption experiments of negative ions using low energy incident electrons and time-of-flight identification of the desorbed ions. It consists of a pulsed electron gun, an electrostatic focusing system, and a channel plate detector setup. Electron beams down to sub-eV energies can be used due to electrostatic shielding and the compensation of the earth's magnetic field by a set of Helmholtz coils. The main advantage is the large acceptance for ions of all masses, energies, and desorption angles at the same time, which keeps measuring time reasonably short and allows us to gain information before degeneration of the irradiated sample occurs, even if weak desorption channels are investigated. We demonstrate the power of our setup with first results from a boron doped, (100)-oriented diamond sample, which is partly oxidized and partly hydrogenated with some water contaminations on it. Different binding states of oxygen are disclosed clearly by different desorption thresholds. The C-O binding on oxidized diamond forms a carbonyl group. The 1b2 orbital of water can be seen in a O desorption threshold. The yield of negative hydrogen desorption shows a linear increase for incident electron energies higher than 13 eV. It results from a dipolar dissociation as has been published previously.

  6. Site-specific photochemistry

    NASA Astrophysics Data System (ADS)

    Koplitz, Brent D.; Brum, Jeffrey L.; Deshmukh, Subhash; Xu, Xiaodong; Wang, Zhongrui; Yen, Yu-Fong

    1992-04-01

    We present results on `site-specific' H-atom production in photolysis experiments conducted under collisionless conditions. H and D atoms are used as labels to investigate the site(s) at which C-H (or C-D) bond cleavage occurs in a variety of haloalkane systems. Experiments using two photolysis lasers clearly indicate that photon absorption by an intermediate, presumably an alkyl radical, is important in many of the systems studied. The site(s) (e.g., (alpha) , (beta) , or (gamma) ) at which C-H (or C-D) bond cleavage occurs is dependent not only on the nature of the molecule, but also on the photolysis wavelength. As a diagnostic tool, H- and D-atom Doppler spectroscopy allows us to gain insight into the energetics associated with the various dissociation processes. Our overall aim is to gain a further understanding of the photolysis properties of a variety of simple molecules and their associated radicals.

  7. Remote mass spectrometric sampling of electrospray- and desorption electrospray-generated ions using an air ejector.

    PubMed

    Dixon, R Brent; Bereman, Michael S; Muddiman, David C; Hawkridge, Adam M

    2007-10-01

    A commercial air ejector was coupled to an electrospray ionization linear ion trap mass spectrometer (LTQ) to transport remotely generated ions from both electrospray (ESI) and desorption electrospray ionization (DESI) sources. We demonstrate the remote analysis of a series of analyte ions that range from small molecules and polymers to polypeptides using the AE-LTQ interface. The details of the ESI-AE-LTQ and DESI-AE-LTQ experimental configurations are described and preliminary mass spectrometric data are presented. PMID:17716909

  8. Remote Mass Spectrometric Sampling of Electrospray- and Desorption Electrospray-Generated Ions Using an Air Ejector

    PubMed Central

    Dixon, R. Brent; Bereman, Michael S.; Muddiman, David C.; Hawkridge, Adam M.

    2007-01-01

    A commercial air ejector was coupled to an electrospray ionization linear ion trap mass spectrometer (LTQ) to transport remotely generated ions from both electrospray (ESI) and desorption electrospray ionization (DESI) sources. We demonstrate the remote analysis of a series of analyte ions that range from small molecules and polymers to polypeptides using the AE-LTQ interface. The details of the ESI-AE-LTQ and DESI-AE-LTQ experimental configurations are described and preliminary mass spectrometric data is presented. PMID:17716909

  9. Novel sampling methods for use with thermal desorption ion trap mass spectrometry

    SciTech Connect

    Barshick, S.A.; Buchanan, M.V.

    1994-12-31

    Novel sampling approaches have been investigated to improve the analytical utility of thermal desorption Direct Sampling Ion Trap Mass Spectrometry (DSITMS). Because DSITMS involves the direct introduction of samples into an ion trap mass spectrometer, problems with detection capabilities (sensitivity and selectivity) can often occur when performing trace analysis in complex matrices. Various sampling approaches have been evaluated to improve thermal desorption detection capabilities and to extend the utilities of DSITMS methodologies without significantly increasing analysis times or the cost-effectiveness of DSITMS methods. Three sampling approaches have been investigated including solid phase microextraction (SPME), solid phase extraction columns (SPEC), and purge and trap.

  10. Photon-stimulated ion desorption from molybdenum oxides following Mo 2p3/2 excitation.

    PubMed

    Wu, G; Baba, Y; Sekiguchi, T; Shimoyama, I

    2001-03-01

    Photon-stimulated ion desorption from solid MoO3 following the Mo 2p3/2 resonant transition has been investigated. In the XANES spectrum, Mo 2p3/2 peak is split into two components corresponding to the excitations from Mo 2p3/2 into the t2g and e(g) orbitals. It was observed that the desorption yield of O+ ions at the Mo 2p3/2-->e(g) resonance is higher than that at the Mo 2p3/2-->t2g resonance. The Auger decay spectra reveal that there exist two kinds of spectator Auger decays. The high desorption yield at the 2p3/2-->e(g) resonance is interpreted by the fast breaking of the Mo-O bond due to the localization of the electrons in the highly antibonding e(g). PMID:11512817

  11. Rhodium Oxide Cluster Ions Studied by Thermal Desorption Spectrometry.

    PubMed

    Mafuné, Fumitaka; Takenouchi, Masato; Miyajima, Ken; Kudoh, Satoshi

    2016-01-28

    Gas-phase rhodium oxide clusters, RhnOm(+), were investigated by measuring the rate constants of oxidation and thermal desorption spectrometry. RhnOm(+) was suggested to be categorized into different states as m/n ≤ 1, 1 < m/n ≤ 1.5, and 1.5 < m/n in terms of energy and kinetics. For m/n ≤ 1, the O atoms readily adsorbed on the cluster with a large binding energy until RhO was formed. Under the O2-rich environment, oxidation proceeded until Rh2O3 was formed with a moderate binding energy. In addition, O2 molecules attached weakly to the cluster, and Rh2O3 formed RhnOm(+) (1.5 < m/n). The energetics and geometries of Rh6Om(+) (m = 6-12) were obtained using density functional theory calculations and were found to be consistent with the experimental results. PMID:26730616

  12. Study on the desorption yield for natural botanic sample induced by energetic heavy ions

    NASA Astrophysics Data System (ADS)

    Xue, J. M.; Wang, Y. G.; Du, G. H.; Yan, S.; Zhao, W. J.

    2002-12-01

    The dependence of desorption yield for the natural botanic sample bombarded with heavy ion on the electronic stopping power ( Se) and dose has been measured by weighing sample mass before and after irradiation. Primary ions including 50 keV N +, 1.5 MeV F +, 3.0 MeV F 2+, 4.0 MeV F 2+ and 3.0 MeV Si 2+ were used in the experiment. Three megaelectron volts of F 2+ with doses ranging from 4×10 15 to 4×10 16 ions/cm 2 were used in order to investigate the influence of ion dose. A mass spectrum from the sample bombarded with 3 MeV Si 2+ was also taken for a better understanding of the desorption process. Results show that the natural botanic sample is very easily to be desorpted. The yield of MeV heavy ions can be as high as thousands CH 2O/ion, and significantly depends on both the Se and dose. The measured yields increase quickly with Se, but drop down with increasing ion dose. These results fit roughly with the prediction of the pressure pulse model.

  13. Nonlinear effects in desorption of valine with fast incident molecular ions

    SciTech Connect

    Salehpour, M.; Fishel, D.L.; Hunt, J.E.

    1988-12-15

    Fast molecular ions as primary particles have been used to study secondary-ion desorption from organic layers. The secondary molecular-ion yield of the amino acid valine (molecular weight, 117) has been measured as a function of the velocity of primary atomic and molecular incident ions. The primary ions used were C/sup +/, O/sup +/, Ar/sup +/, C/sub 2//sup +/, O/sub 2//sup +/ , CO/sup +/, CO/sub 2//sup +/, CH/sup +/, CH/sub 3//sup +/, CF/sup +/, CF/sub 3//sup +/, C/sub 3/F/sub 5//sup +/, and C/sub 4/F/sub 7//sup +/ in the energy range 600 keV--3.7 MeV. The secondary molecular-ion yields, when compared to yields for atomic constituents, unambiguously show that collective effects exist in desorption with incident molecular ions. Results are discussed in the framework of enhancement in the electronic stopping power per atom for molecular ions due to the vicinage of the fast-moving charges in the material. The resulting high-yield enhancements, especially with the use of large incident ions such as C/sub 3/F/sub 5//sup +/ and C/sub 4/F/sub 7//sup +/, are very encouraging for the future of mass spectrometry of large organic molecules.

  14. Laser desorption with corona discharge ion mobility spectrometry for direct surface detection of explosives.

    PubMed

    Sabo, M; Malásková, M; Matejčík, S

    2014-10-21

    We present a new highly sensitive technique for the detection of explosives directly from the surface using laser desorption-corona discharge-ion mobility spectrometry (LD-CD-IMS). We have developed LD based on laser diode modules (LDM) and the technique was tested using three different LDM (445, 532 and 665 nm). The explosives were detected directly from the surface without any further preparation. We discuss the mechanism of the LD and the limitations of this technique such as desorption time, transport time and desorption area. After the evaluation of experimental data, we estimated the potential limits of detection of this method to be 0.6 pg for TNT, 2.8 pg for RDX and 8.4 pg for PETN. PMID:25118619

  15. Formation of Metal-Related Ions in Matrix-Assisted Laser Desorption Ionization.

    PubMed

    Lee, Chuping; Lu, I-Chung; Hsu, Hsu Chen; Lin, Hou-Yu; Liang, Sheng-Ping; Lee, Yuan-Tseh; Ni, Chi-Kung

    2016-09-01

    In a study of the metal-related ion generation mechanism in matrix-assisted laser desorption ionization (MALDI), crystals of matrix used in MALDI were grown from matrix- and salt-containing solutions. The intensities of metal ion and metal adducts of the matrix ion obtained from unwashed crystals were higher than those from crystals washed with deionized water, indicating that metal ions and metal adducts of the matrix ions are mainly generated from the surface of crystals. The contributions of preformed metal ions and metal adducts of the matrix ions inside the matrix crystals were minor. Metal adducts of the matrix and analyte ion intensities generated from a mixture of dried matrix, salt, and analyte powders were similar to or higher than those generated from the powder of dried droplet crystals, indicating that the contributions of the preformed metal adducts of the matrix and analyte ions were insignificant. Correlation between metal-related ion intensity fluctuation and protonated ion intensity fluctuation was observed, indicating that the generation mechanism of the metal-related ions is similar to that of the protonated ions. Because the thermally induced proton transfer model effectively describes the generation of the protonated ions, we suggest that metal-related ions are mainly generated from the salt dissolution in the matrix melted by the laser. Graphical Abstract ᅟ. PMID:27306427

  16. Formation of Metal-Related Ions in Matrix-Assisted Laser Desorption Ionization

    NASA Astrophysics Data System (ADS)

    Lee, Chuping; Lu, I.-Chung; Hsu, Hsu Chen; Lin, Hou-Yu; Liang, Sheng-Ping; Lee, Yuan-Tseh; Ni, Chi-Kung

    2016-06-01

    In a study of the metal-related ion generation mechanism in matrix-assisted laser desorption ionization (MALDI), crystals of matrix used in MALDI were grown from matrix- and salt-containing solutions. The intensities of metal ion and metal adducts of the matrix ion obtained from unwashed crystals were higher than those from crystals washed with deionized water, indicating that metal ions and metal adducts of the matrix ions are mainly generated from the surface of crystals. The contributions of preformed metal ions and metal adducts of the matrix ions inside the matrix crystals were minor. Metal adducts of the matrix and analyte ion intensities generated from a mixture of dried matrix, salt, and analyte powders were similar to or higher than those generated from the powder of dried droplet crystals, indicating that the contributions of the preformed metal adducts of the matrix and analyte ions were insignificant. Correlation between metal-related ion intensity fluctuation and protonated ion intensity fluctuation was observed, indicating that the generation mechanism of the metal-related ions is similar to that of the protonated ions. Because the thermally induced proton transfer model effectively describes the generation of the protonated ions, we suggest that metal-related ions are mainly generated from the salt dissolution in the matrix melted by the laser.

  17. Formation of Metal-Related Ions in Matrix-Assisted Laser Desorption Ionization

    NASA Astrophysics Data System (ADS)

    Lee, Chuping; Lu, I.-Chung; Hsu, Hsu Chen; Lin, Hou-Yu; Liang, Sheng-Ping; Lee, Yuan-Tseh; Ni, Chi-Kung

    2016-09-01

    In a study of the metal-related ion generation mechanism in matrix-assisted laser desorption ionization (MALDI), crystals of matrix used in MALDI were grown from matrix- and salt-containing solutions. The intensities of metal ion and metal adducts of the matrix ion obtained from unwashed crystals were higher than those from crystals washed with deionized water, indicating that metal ions and metal adducts of the matrix ions are mainly generated from the surface of crystals. The contributions of preformed metal ions and metal adducts of the matrix ions inside the matrix crystals were minor. Metal adducts of the matrix and analyte ion intensities generated from a mixture of dried matrix, salt, and analyte powders were similar to or higher than those generated from the powder of dried droplet crystals, indicating that the contributions of the preformed metal adducts of the matrix and analyte ions were insignificant. Correlation between metal-related ion intensity fluctuation and protonated ion intensity fluctuation was observed, indicating that the generation mechanism of the metal-related ions is similar to that of the protonated ions. Because the thermally induced proton transfer model effectively describes the generation of the protonated ions, we suggest that metal-related ions are mainly generated from the salt dissolution in the matrix melted by the laser.

  18. Liquid Beam Ion Desorption Mass Spectrometry for Evaluating CASSINI Data

    NASA Astrophysics Data System (ADS)

    Stolz, Ferdinand; Reviol, Rene; Srama, Ralf; Trieloff, Mario; Postberg, Frank; Abel, Bernd

    2013-04-01

    Saturn's moon Enceladus emits plumes of ice particles from an area near its south pole which are detected and chemically analyzed by the Cosmic Dust Analyzer (CDA) on board the CASSINI spacecraft. Studying these ice particles provides unique insights into Enceladus geological properties. Technically the CDA is a time-of-flight mass spectrometer which delivers mass spectra of the particles and their fragments. Since interpretation of the available CDA data is particularly challenging we employ a laboratory experiment to imitate experimental conditions in space. Key part of our experimental setup is a micron-sized water beam in high vacuum. This beam is rapidly heated up by an infrared laser pulse, which is tuned to excite the OH-stretch vibration of water molecules. This causes the water beam to dissipate into small droplets, some of which carry a net charge even though the laser energy is well below the molecular ionisation energy. The charged droplets are then analyzed in a time-of-flight mass spectrometer. With this experimental setup we successfully simulated the space born ice particles measured at Enceladus. By varying the laser intensity in our experiments, we can vary the amount of energy deposited in the liquid beam, and thus model different particle velocities. Also, variation of solute concentration in the water beam provides valuable information about ice particle composition. Some examples for anorganic solutes studied so far are sodium chloride, ammonia and hydrogen sulfite. A special feature of our experimental technique is that desorption of particles from the liquid beam is particularly soft. This is explained by the fact that all laser energy is absorbed by the water molecules. In this way molecular bonds of solutes stay intact and molecular solutes are transferred into the droplet phase without getting destroyed. This is particularly interesting in the context of analyzing organic compounds - some of which have been detected at Enceladus. Using

  19. Brominated Tyrosine and Polyelectrolyte Multilayer Analysis by Laser Desorption VUV Postionization and Secondary Ion Mass Spectrometry

    PubMed Central

    Melvin Blaze, M.T.; Takahashi, Lynelle K.; Zhou, Jia; Ahmed, Musahid; Gasper, Gerald L.; Pleticha, F. Douglas; Hanley, Luke

    2011-01-01

    The small molecular analyte 3,5-dibromotyrosine (Br2Y) and chitosan-alginate polyelectrolyte multilayers (PEM) with and without adsorbed Br2Y were analyzed by laser desorption postionization mass spectrometry (LDPI-MS). LDPI-MS using 7.87 eV laser and tunable 8 – 12.5 eV synchrotron vacuum ultraviolet (VUV) radiation found that desorption of clusters from Br2Y films allowed detection by ≤8 eV single photon ionization. Thermal desorption and electronic structure calculations determined the ionization energy of Br2Y to be ~8.3±0.1 eV and further indicated that the lower ionization energies of clusters permitted their detection at ≤8 eV photon energies. However, single photon ionization could only detect Br2Y adsorbed within PEMs when using either higher photon energies or matrix addition to the sample. All samples were also analyzed by 25 keV Bi3+ secondary ion mass spectrometry (SIMS), with the negative ion spectra showing strong parent ion signal which complemented that observed by LDPI-MS. However, the negative ion SIMS appeared strongly dependent on the high electron affinity of this specific analyte and the analyte’s condensed phase environment. PMID:21548612

  20. Brominated Tyrosine and Polyelectrolyte Multilayer Analysis by Laser Desorption VUV Postionization and Secondary Ion Mass Spectrometry

    SciTech Connect

    University of Illinois at Chicago; Blaze, Melvin M. T.; Takahashi, Lynelle; Zhou, Jia; Ahmed, Musahid; Gasper, Gerald; Pleticha, F. Douglas; Hanley, Luke

    2011-03-14

    The small molecular analyte 3,5-dibromotyrosine (Br2Y) and chitosan-alginate polyelectrolyte multilayers (PEM) with and without adsorbed Br2Y were analyzed by laser desorption postionization mass spectrometry (LDPI-MS). LDPI-MS using 7.87 eV laser and tunable 8 ? 12.5 eV synchrotron vacuum ultraviolet (VUV) radiation found that desorption of clusters from Br2Y films allowed detection by≤8 eV single photon ionization. Thermal desorption and electronic structure calculations determined the ionization energy of Br2Y to be ~;;8.3?0.1 eV and further indicated that the lower ionization energies of clusters permitted their detection at≤8 eV photon energies. However, single photon ionization could only detect Br2Y adsorbed within PEMs when using either higher photon energies or matrix addition to the sample. All samples were also analyzed by 25 keV Bi3 + secondary ion mass spectrometry (SIMS), with the negative ion spectra showing strong parent ion signal which complemented that observed by LDPI-MS. The negative ion SIMS depended strongly on the high electron affinity of this specific analyte and the analyte?s condensed phase environment.

  1. Silica-fiber microextraction for laser desorption ion trap mass spectrometry

    SciTech Connect

    Cisper, M.E.; Earl, W.L.; Nogar, N.S.; Hemberger, P.H. )

    1994-06-01

    We have coupled sample collection by solid-phase microextraction on disposable fused silica optical fibers with analysis by laser desorption ion trap mass spectrometry for rapid screening of organic contaminants in complex matrices. Because the silica-fiber probe serves as both the sampling medium and the sample support for laser desorption, traditional methods of sample preparation are eliminated with the expected gains in speed and simplicity. Pyrene was the benchmark compound in these experiments but we show that the technique is also applicable to other polycyclic aromatic hydrocarbons (PAHs) and semivolatile compounds, laser dyes, pesticides, and peptides. Derivatizing the silica fiber improves the analyte collection efficiency, and firing the laser during a ring electrode rf ramp promotes dependable trapping of laser-desorbed ions. 32 refs., 5 figs.

  2. Development of microscopy for lithium analysis using medium-energy ion-stimulated desorption

    NASA Astrophysics Data System (ADS)

    Kobayashi, Takane; Kamoshida, Atsushi; Akiyama, Hideo; Watanabe, Ken; Ohnishi, Tsuyoshi; Takada, Kazunori; Suzuki, Taku T.

    2014-10-01

    A medium-energy ion-stimulated desorption spectroscope was combined with a helium ion microscope to develop a microscope for lithium (Li) analysis with high spatial resolution below 10 nm. The analysis of Li is based on time-of-flight (TOF) spectroscopy. A clear Li peak was observed in the TOF spectra for the samples containing Li. The capability of the microscope was demonstrated using a LiCoO2/Nb doped SrTiO3 sample. Furthermore, the Li distribution on the sample was successfully observed by measuring the Li+ peak intensity as a function of the helium irradiation position.

  3. Competing ion decomposition channels in matrix-assisted laser desorption ionization.

    PubMed

    Luo, Guanghong; Marginean, Ioan; Ye, Louise; Vertes, Akos

    2008-06-12

    We gauged the internal energy transfer for two dissociative ion decomposition channels in matrix-assisted laser desorption ionization (MALDI) using the benzyltriphenylphosphonium (BTP) thermometer ion [PhCH 2PPh 3] (+). Common MALDI matrixes [alpha-cyano-4-hydroxycinnamic acid (CHCA), 3,5-dimethoxy-4-hydroxycinnamic acid (sinapinic acid, SA), and 2,5-dihydroxycinnamic acid (DHB)] were studied with nitrogen laser (4 ns pulse length) and mode-locked 3 x omega Nd:YAG laser (22 ps pulse length) excitation. Despite the higher fluence required to initiate fragmentation, BTP ions indicated lower internal energy transfer with the picosecond laser in all three matrixes. These differences can be rationalized in terms of phase explosion induced by the nanosecond laser vs a stress-confinement-driven desorption mechanism for the picosecond laser. For the two ion production channels of the BTP thermometer ion, breaking a single bond can result in the formation of benzyl/tropylium ions, F1, or triphenylphosphine ions, F2. In SA and DHB, as well as in CHCA at low fluence levels, the efficiency of these channels (expressed by the branching ratio I F1/ I F2) is moderately in favor of producing tropylium ions, 1 < I F1/ I F2 < 6. As the laser fluence is increased, for CHCA, there is a dramatic shift in favor of the tropylium ion production, with I F1/ I F2 approximately 30 for the nanosecond and the picosecond laser, respectively. This change is correlated with the sudden increase in the BTP internal energies in CHCA in the same laser fluence range. The large changes observed in internal energy deposition for CHCA with laser fluence can account for its ability to induce fragmentation in peptides more readily than SA and DHB. PMID:18489138

  4. Swift heavy ion irradiation of Pt nanocrystals: II. Structural changes and H desorption

    SciTech Connect

    Giulian, R.; Araujo, L.L.; Kluth, P.; Sprouster, D.J.; Schnohr, C.S.; Byrne, A.P.; Ridgway, M.C.

    2014-09-24

    The structural properties and H desorption from embedded Pt nanocrystals (NCs) following irradiation with swift heavy ions were investigated as a function of energy and fluence. From x-ray absorption near-edge spectroscopy analysis, Pt-H bonding was identified in NCs annealed in a forming gas (95% N{sub 2} + 5% H{sub 2}) ambient. The H content decreased upon irradiation and the desorption process was NC-size dependent such that larger NCs required a higher fluence to achieve a H-free state. Pt-H bonding and NC dissolution both perturbed the NC structural parameters (coordination number, bond-length and mean-square relative displacement) as determined with extended x-ray absorption fine structure measurements.

  5. Angular distributions of surface produced H{sup −} ions for reflection and desorption processes

    SciTech Connect

    Wada, M. Kasuya, T.; Kenmotsu, T.; Sasao, M.

    2014-02-15

    A numerical simulation code, Atomic Collision in Amorphous Target, has been run to clarify the effects due to the incident angle of hydrogen flux onto surface collision cascade in the subsurface region of a Cs covered Mo plasma grid. The code has taken into account the threshold energy for negative hydrogen (H{sup −}) ions to leave the surface. This modification has caused the shift of energy distribution functions of H{sup −} from that of hydrogen atoms leaving the surface. The results have shown that large incident angle of hydrogen particle tilt the angular distribution of reflection component, while it caused a small effect onto the angular distribution of desorption component. The reflection coefficient has increased, while the desorption yield has decreased for increased angle of incidence measured from the surface normal.

  6. Metal ion sorption and desorption on zeolitized tuffs from the Nevada Test Site

    SciTech Connect

    Um, Wooyong; Papelis, Charalambos

    2004-01-15

    Because of the hundreds of nuclear weapon tests conducted on the Nevada Test Site (NTS) during the Cold War, the migration of radionuclides and contaminants is a potential concern. The mobility of these compounds and our ability to remediate contaminated sites are controlled by sorption and desorption processes, which depend frequently on the nature of the contaminant, the mineralogy of the site, and the geochemical conditions. The sorption and desorption behavior of strontium (Sr) and lead (Pb), two metal cations with different chemistries, commonly found on nuclear test sites were studied. Strontium showed pH-independent and ionic-strength-dependent sorption, consistent with ion exchange processes at permanent charge sorption sites. The sorption uptake of Sr increased with decreasing ionic strength of background solution. Strontium desorption from the adsorbents was enhanced by increased background electrolyte concentration and was a function of background electrolyte composition . The fractional uptake of Pb was higher, compared to Sr, and was only pH dependent at the highest ionic strength used (1.0 M). This pH-dependent sorption behavior, consistent with formation of surface complexes at amphoteric surface hydroxyl sites or formation of surface precipitates, could explain the decreased Pb desorption, compared to Sr, especially at increased background electrolyte concentrations. Under conditions typical for the groundwater at the NTS (I = 0.003 M, pH = 8.0), both Pb and Sr are expected to bind strongly on tuffs with composition similar to the zeolitized tuffs used in this study. Any increase in the dissolved ion concentration of the groundwater, however, may result in, at least partial, release of Sr and enhanced Sr mobility.

  7. Site-specific cleavage by metal ion cofactors and inhibitors of M1 RNA, the catalytic subunit of RNase P from Escherichia coli.

    PubMed Central

    Kazakov, S; Altman, S

    1991-01-01

    The location of phosphate residues involved in specific centers for binding of metal ions in M1 RNA, the catalytic RNA subunit of RNase P from Escherichia coli, was determined by analysis of induction of cleavage of RNA by metal ions. At pH 9.5, Mg2+ catalyzes cleavage of M1 RNA at five principal sites. Under certain conditions, Mn2+ and Ca2+ can each replace Mg2+ as the cofactor in the processing of precursor tRNAs by M1 RNA and P RNA, the RNA subunit of RNase P from Bacillus subtilis. These cations, as well as various metal ion inhibitors of the catalytic activity of M1 RNA, also promote cleavage of M1 RNA in a specific manner. Certain conditions that affect the catalytic activity of M1 RNA also alter the rate of metal ion-induced cleavage at the various sites. From these results and a comparison of cleavage of M1 RNA with that of a deletion mutant of M1 RNA and of P RNA, we have identified two different centers for binding of metal ions in M1 RNA that are important for the processing of the precursor to tRNA(Tyr) from E. coli. There is also a center for the binding of metal ions in the substrate, close to the site of cleavage by M1 RNA. Images PMID:1718000

  8. Unravelling the secrets of Cs controlled secondary ion formation: Evidence of the dominance of site specific surface chemistry, alloying and ionic bonding

    NASA Astrophysics Data System (ADS)

    Wittmaack, Klaus

    2013-03-01

    Exposure of ion bombarded solids to Cs gives rise to a very strong enhancement of the yields of negatively charged secondary ions and, concurrently, to a lowering of positive ion yields. The phenomena have been explored in a large number of experimental and theoretical studies but attempts to clarify the mechanism of ion formation were not as successful as assumed. This review examines the state of the art in Cs controlled secondary ion mass spectrometry (SIMS) in great detail, with due consideration of low-energy alkali-ion scattering.In very basic studies on alkali induced secondary ion yield changes, sub-monolayer quantities of Cs or Li were deposited on the sample surface, followed by low-fluence ion bombardment, to avoid significant damage. If SIMS is applied to characterise the composition of solid materials, the simplest approach to achieving sample erosion as well as high negative-ion yields is bombardment with primary ions of Cs. Two other methods of sample loading with Cs provide more flexibility, (i) exposure to a collimated beam of Cs vapour and concurrent bombardment with high-energy non-Cs ions and (ii) the mixed-beam approach involving quasi-simultaneous bombardment with Cs and Xe ions. Both concepts have the advantage that undesirable sample overload with Cs can be avoided. High Cs concentrations reduce the formation probability of target specific molecular ions and lower the yields of all types of positive secondary ions, including Cs+, M+, X+, MCs+ and XCs+ (M and X denoting matrix and impurity elements). Quantitative SIMS analysis using MCs+ and XCs+ ions appears feasible, provided the Cs coverage is kept below about 5%.The semi-classical model of resonant charge transfer, also known as the tunnelling model, has long been considered a solid framework for the interpretation of Cs and Li based SIMS data. The model predicts ionisation probabilities for cases in which, at shallow distances from the surface, the affinity (ionisation) level of the

  9. Unravelling the secrets of Cs controlled secondary ion formation: Evidence of the dominance of site specific surface chemistry, alloying and ionic bonding

    NASA Astrophysics Data System (ADS)

    Wittmaack, Klaus

    2013-03-01

    Exposure of ion bombarded solids to Cs gives rise to a very strong enhancement of the yields of negatively charged secondary ions and, concurrently, to a lowering of positive ion yields. The phenomena have been explored in a large number of experimental and theoretical studies but attempts to clarify the mechanism of ion formation were not as successful as assumed. This review examines the state of the art in Cs controlled secondary ion mass spectrometry (SIMS) in great detail, with due consideration of low-energy alkali-ion scattering. In very basic studies on alkali induced secondary ion yield changes, sub-monolayer quantities of Cs or Li were deposited on the sample surface, followed by low-fluence ion bombardment, to avoid significant damage. If SIMS is applied to characterise the composition of solid materials, the simplest approach to achieving sample erosion as well as high negative-ion yields is bombardment with primary ions of Cs. Two other methods of sample loading with Cs provide more flexibility, (i) exposure to a collimated beam of Cs vapour and concurrent bombardment with high-energy non-Cs ions and (ii) the mixed-beam approach involving quasi-simultaneous bombardment with Cs and Xe ions. Both concepts have the advantage that undesirable sample overload with Cs can be avoided. High Cs concentrations reduce the formation probability of target specific molecular ions and lower the yields of all types of positive secondary ions, including Cs+, M+, X+, MCs+ and XCs+ (M and X denoting matrix and impurity elements). Quantitative SIMS analysis using MCs+ and XCs+ ions appears feasible, provided the Cs coverage is kept below about 5%. The semi-classical model of resonant charge transfer, also known as the tunnelling model, has long been considered a solid framework for the interpretation of Cs and Li based SIMS data. The model predicts ionisation probabilities for cases in which, at shallow distances from the surface, the affinity (ionisation) level of the

  10. Review of heavy-ion induced desorption studies for particle accelerators

    NASA Astrophysics Data System (ADS)

    Mahner, Edgar

    2008-10-01

    During high-intensity heavy-ion operation of several particle accelerators worldwide, large dynamic pressure rises of orders of magnitude were caused by lost beam ions that impacted under grazing angle onto the vacuum chamber walls. This ion-induced desorption, observed, for example, at CERN, GSI, and BNL, can seriously limit the ion intensity, luminosity, and beam lifetime of the accelerator. For the heavy-ion program at CERN’s Large Hadron Collider collisions between beams of fully stripped lead (Pb82+208) ions with a beam energy of 2.76TeV/u and a nominal luminosity of 1027cm-2s-1 are foreseen. The GSI future project FAIR (Facility for Antiproton and Ion Research) aims at a beam intensity of 1012 uranium (U28+238) ions per second to be extracted from the synchrotron SIS18. Over the past years an experimental effort has been made to study the observed dynamic vacuum degradations, which are important to understand and overcome for present and future particle accelerators. The paper reviews the results obtained in several laboratories using dedicated test setups, the mitigation techniques found, and their implementation in accelerators.

  11. Ion-selective Marangoni instability coupled with the nonlinear adsorption/desorption rate.

    PubMed

    Hosohama, Tsugihiko; Megumi, Keitaro; Terakawa, Syuji; Nishimura, Junya; Iida, Youhei; Ban, Takahiko; Shioi, Akihisa

    2011-12-01

    An oil/water interface containing bis(2-ethylhexyl)phosphate and Ca(2+) or Fe(3+) exhibits spontaneous Marangoni instability associated with the fluctuation in interfacial tension. This instability rarely appears for oil/water systems with Mg(2+), Sr(2+), Ba(2+), Cu(2+), or Co(2+). The same ion selectivity is observed for n-heptane and nitrobenzene despite their significant differences in density, viscosity, and the dielectric constant of oil. We studied this instability under acidic pH conditions to avoid the neutralization reaction effects. The result of the equilibrium interfacial tension and the extraction ratio of cations indicates that a large number of oil-soluble complexes form at the interfaces of Ca(2+)-containing systems and probably for Fe(3+)-containing systems. The results obtained by oscillating drop tensiometry and Brewster angle microscopy indicate that desorption, rather than adsorption, is more significant to the onset of instability and that the resulting complex tends to form aggregates in the interface. This aggregation gives the nonlinear desorption rate of the oil-soluble complex. Then, exfoliation of the aggregating matter occurs, which triggers the Marangoni instability. The induced convection removes the oil-soluble complex accumulated at the interface, creating a renewed interface, which is necessary for the successive occurrence of the Marangoni instability. For the other cations, the oil-soluble compounds are insignificant, and they rarely form aggregates. In such cases, adsorption/desorption proceeds without instability. PMID:22017536

  12. Desorption/ionization of acrylamide in aqueous solutions in atmospheric pressure air using a microdischarge with vortex focusing of ions

    NASA Astrophysics Data System (ADS)

    Pervukhin, V. V.; Sheven', D. G.

    2014-09-01

    A method of desorption/ionization in a microdischarge with ion vortex focusing (vortex focusing microdischarge, VFM) is suggested. A glow microdischarge is initiated in an air flow, and resulting ions act on the surface of interest. As a model compound, an aqueous solution of acrylamide is taken. Desorption/ionization taking place under atmospheric pressure is followed by the mass-spectrometric identification of the ions. The operating parameters of the VFM system are studied and optimized. Upon optimization of the system, the detection limit of acrylamide trace amounts in aqueous solutions is determined using the suggested method of desorption/ionization and analyte ion focusing with a vortex (swirling) jet. The acrylamide detection limit is found to be 2 × 10-3 g/L.

  13. Free-electron-laser (FEL)-induced desorption of ions from tooth dentine

    NASA Astrophysics Data System (ADS)

    Ogino, Seiji; Awazu, Kunio; Tomimasu, Takio

    1997-05-01

    Free electron laser (FEL) with the wide wavelength tunability has been developed and used for various applications. The FEL gives high efficiency for the photo- induced ablation when the laser is tuned to an absorption maximum of the target. This study investigates the FEL induced desorption of ions from tooth dentine to find new possibility for laser dentistry. The FEL was tuned to 9.4 (Mu) m, which is an absorption maximum of phosphoric acid ion known as major component of dentine. The FEL pulse length was several ps. The output average power was varied from 5 to 20mW by filters. A time-of-flight mass spectroscopy systems were developed for the purpose of analyzing the desorbed ions of varying masses. After the 9.4 micrometers FEL irradiation, the dentine surface was ablated, and visible light emission was observed. As a result, positive ions which correspond to Na+ and many phosphoric acid ions were measured. The positive ions, however were not observed when the FEL was not tuned to the absorption peak of the target. Therefore, this wavelength dependence points to resonant multiphoton vibrational excitation of molecules by the 9.4 micrometers FEL irradiation.

  14. Rapid determination of nicotine in urine by direct thermal desorption ion trap mass spectrometry

    SciTech Connect

    Wise, M.B.; Ilgner, R.H.; Guerin, M.R.

    1990-01-01

    The measurement of nicotine and cotinine in physiological fluids (urine, blood serum, and saliva) is widely used as a means of assessing human exposure to environmental tobacco smoke (ETS). Although numerous analytical methods exist for these measurements, they generally involve extensive sample preparation which increases cost and decreases sample throughput. We report the use of thermal desorption directly into an ion trap mass spectrometer (ITMS) for the rapid determination of nicotine and cotinine in urine. A 1{mu}L aliquot of urine is injected into a specially designed inlet and flash vaporized directly into an ITMS through an open-split capillary restrictor interface. Isobutane chemical ionization is used to generate (M+H){sup +} ions of the analytes and collision induced dissociation is used to generate characteristic fragment ions which are used to confirm their identity. Quantification is achieved by integrating the ion current for the characteristic ions and comparing with an external working curve. Detection limits are approximately 50 pg per analyte and the sample turnaround time is approximately 3 minutes without the need for extensive sample preparation. 12 refs., 5 figs.

  15. A focused ion beam milling and lift-out approach for site-specific preparation of frozen-hydrated lamellas from multicellular organisms.

    PubMed

    Mahamid, Julia; Schampers, Ruud; Persoon, Hans; Hyman, Anthony A; Baumeister, Wolfgang; Plitzko, Jürgen M

    2015-11-01

    Cryo-electron tomography provides 3D views of cellular architecture with molecular resolution. A principal limitation of cryo-transmission electron microscopy performed on cells or tissues is the accessible specimen thickness. Recently it has been shown that cryo-focused ion beam milling of plunge-frozen eukaryotic cells can produce homogeneously thin, distortion free lamellas for cryo-electron tomography. Multicellular organisms and tissue cannot be properly vitrified and thinned using this technique because they are considerably thicker. High pressure freezing is therefore necessary to provide optimal preservation. Here, we describe a workflow for preparing lamellas from Caenorhabditis elegans worms using cryo-FIB applied to high pressure frozen samples. We employ cryo-planing followed by correlative cryo-fluorescence microscopy to navigate this large multicellular volume and to localize specific targets within. To produce vitreous lamellas amenable to cryo-TEM observations at these targeted locations, we have developed a dedicated lift-out procedure at cryogenic temperature. PMID:26216184

  16. Assessment of Laser-Induced Thermal Load on Silicon Nanostructures Based on Ion Desorption Yields

    SciTech Connect

    Walker, Bennett N; Stolee, Jessica A; Pickel, Deanna L; Retterer, Scott T; Vertes, Akos

    2010-01-01

    Laser heating of macroscopic objects follows the Fourier law of diffusive heat conduction. However, when the dimensions of a structure approach the mean free path of the phonons, heat transport is properly described by the equations of ballistic-diffusive or ballistic transport. Due to the coexistence of these different mechanisms in most nanostructures, the description of their rapid laser heating becomes complex. Experimental assessment of the thermal load on these structures through IR imaging is currently too slow and lacks the spatial resolution to be useful. In this paper, we introduce a method based on measuring the laser-induced yields of quasimolecular ions that enables the comparison of the thermal loads on different structures. Due to the difference in the activation energies of the desorption processes, sodiated and potassiated peptide ion intensities become equal at a certain surface temperature. The laser fluences at which these ion yields are equal for two different structures correspond to equivalent thermal loads. As an example, we compare the nanosecond laser heating of silicon nanopost arrays (NAPA) with diverse post diameters and periodicities. Assessment of the thermal load through ion yield measurements can also be used to verify model assumptions for heat transport regimes of nanostructures.

  17. Helium reemission, desorption and microstructure evolution of graphites under helium ion implantation

    NASA Astrophysics Data System (ADS)

    Alimov, V. Kh.; Scherzer, B. M. U.; Chernikov, V. N.; Ullmaier, H.

    1995-07-01

    Helium reemission, trapping, and thermal desorption from highly ordered pyrolytic graphite (HOPG and HPG) of different orientation, polycrystalline graphite (EK98), and titanium doped graphite (RG-Ti-91) have been measured at irradiation temperatures of 300 K and 800 K. The implantation was performed with a 40 keV 4He ion beam. Detailed transmission electron microscopy (TEM) investigation of the microstructure evolution was made on the implanted specimens. He reemission from basal oriented (BO) highly oriented pyrolytic graphite is accompanied by blistering and flaking leading to repetitive gas bursts. On edge oriented (EO) pyrolytic graphite three reemission peaks are observed during room temperature implantation, the first and smallest one being assigned to He release from intrinsic lenticular cavities, the second one occurs during early bubble formation when a small amount of implanted gas still escapes accumulation, and the third and largest peak being due to He release by bubble coalescence. The He reemission rate grows very slowly at room temperature and does not reach 100% up to the highest implanted fluence of 3.5ṡ1018 He/cm2. At 800 K the He reemission rate from EO pyrolytic graphite reaches 100% immediately after starting implantation due to the high diffusive mobility of He. EK98 and RG-Ti-91 show similar reemission behaviour. No gas bursts due to blistering are observed. The initial reemission rate at 300 K is higher than in EO pyrolytic graphite due to release of He via a network of intergranular channels. At 800 K reemission is rather similar to that from EO pyrolytic graphite. No thermal desorption of He from BO HOPG up to 1200 K is observed for implanted fluences ≤1016 He/cm2. At higher fluences the onset temperature of desorption decreases from 750 K at 2ṡ1016 He/cm2 to 380 K at 1017 He/cm2 caused by thermal flaking due to pressure increase of He in submicroscopic cracks. In the other materials two desorption peaks are observed, the first one

  18. Ammonium Ion Exchanged Zeolite for Laser Desorption/Ionization Mass Spectrometry of Phosphorylated Peptides

    PubMed Central

    Yang, Mengrui; Fujino, Tatsuya

    2015-01-01

    α-Cyano-4-hydroxycinnamic acid (CHCA), an organic matrix molecule for matrix-assisted laser desorption/ionization mass spectrometry, was adsorbed to NH4+-type zeolite surface, and this new matrix was used for the detection of low-molecular-weight compounds. It was found that this matrix could simplify the mass spectrum in the low-molecular-weight region and prevent interference from fragments and alkali metal ion adducted species. CHCA adsorbed to NH4+-type ZSM5 zeolite (CHCA/NH4ZSM5) was used to measure atropine and aconitine, two toxic alkaloids in plants. In addition, CHCA/NH4ZSM5 enabled us to detect phosphorylated peptides; peaks of the protonated peptides had higher intensities than the peaks observed using CHCA only. PMID:26448749

  19. Leidenfrost Phenomenon-assisted Thermal Desorption (LPTD) and Its Application to Open Ion Sources at Atmospheric Pressure Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Saha, Subhrakanti; Chen, Lee Chuin; Mandal, Mridul Kanti; Hiraoka, Kenzo

    2013-03-01

    This work describes the development and application of a new thermal desorption technique that makes use of the Leidenfrost phenomenon in open ion sources at atmospheric pressure for direct mass spectrometric detection of ultratrace levels of illicit, therapeutic, and stimulant drugs, toxicants, and peptides (molecular weight above 1 kDa) in their unaltered state from complex real world samples without or with minor sample pretreatment. A low temperature dielectric barrier discharge ion source was used throughout the experiments and the analytical figures of merit of this technique were investigated. Further, this desorption technique coupled with other ionization sources such as electrospray ionization (ESI) and dc corona discharge atmospheric pressure chemical ionization (APCI) in open atmosphere was also investigated. The use of the high-resolution `Exactive Orbitrap' mass spectrometer provided unambiguous identification of trace levels of the targeted compounds from complex mixtures and background noise; the limits of detection for various small organic molecules and peptides treated with this technique were at the level of parts per trillion and 10-9 M, respectively. The high sensitivity of the present technique is attributed to the spontaneous enrichment of analyte molecules during the slow evaporation of the solvent, as well as to the sequential desorption of molecules from complex mixtures based on their volatilities. This newly developed desorption technique is simple and fast, while molecular ions are observed as the major ions.

  20. Leidenfrost phenomenon-assisted thermal desorption (LPTD) and its application to open ion sources at atmospheric pressure mass spectrometry.

    PubMed

    Saha, Subhrakanti; Chen, Lee Chuin; Mandal, Mridul Kanti; Hiraoka, Kenzo

    2013-03-01

    This work describes the development and application of a new thermal desorption technique that makes use of the Leidenfrost phenomenon in open ion sources at atmospheric pressure for direct mass spectrometric detection of ultratrace levels of illicit, therapeutic, and stimulant drugs, toxicants, and peptides (molecular weight above 1 kDa) in their unaltered state from complex real world samples without or with minor sample pretreatment. A low temperature dielectric barrier discharge ion source was used throughout the experiments and the analytical figures of merit of this technique were investigated. Further, this desorption technique coupled with other ionization sources such as electrospray ionization (ESI) and dc corona discharge atmospheric pressure chemical ionization (APCI) in open atmosphere was also investigated. The use of the high-resolution 'Exactive Orbitrap' mass spectrometer provided unambiguous identification of trace levels of the targeted compounds from complex mixtures and background noise; the limits of detection for various small organic molecules and peptides treated with this technique were at the level of parts per trillion and 10(-9) M, respectively. The high sensitivity of the present technique is attributed to the spontaneous enrichment of analyte molecules during the slow evaporation of the solvent, as well as to the sequential desorption of molecules from complex mixtures based on their volatilities. This newly developed desorption technique is simple and fast, while molecular ions are observed as the major ions. PMID:23423791

  1. Characterization of the Cathode Electrolyte Interface in Lithium Ion Batteries by Desorption Electrospray Ionization Mass Spectrometry.

    PubMed

    Liu, Yao-Min; G Nicolau, Bruno; Esbenshade, Jennifer L; Gewirth, Andrew A

    2016-07-19

    The solid electrolyte interface (SEI) formed via electrolyte decomposition on the anode of lithium ion batteries is largely responsible for the stable cycling of conventional lithium ion batteries. Similarly, there is a lesser-known analogous layer on the cathode side of a lithium ion battery, termed the cathode electrolyte interface (CEI), whose composition and role are debated. To confirm the existence and composition of the CEI, desorption electrospray ionization mass spectrometry (DESI-MS) is applied to study common lithium ion battery cathodes. We observe CEI formation on the LiMn2O4 cathode material after cycling between 3.5 and 4.5 V vs Li/Li(+) in electrolyte solution containing 1 M LiPF6 or LiClO4 in 1:1 (v/v) ethylene carbonate (EC) and dimethyl carbonate (DMC). Intact poly(ethylene glycol) dimethyl ether is identified as the electrolyte degradation product on the cathode surface by the high mass-resolution Orbitrap mass spectrometer. When EC is paired with ethyl methyl carbonate (EMC), poly(ethylene glycol) dimethyl ether, poly(ethylene glycol) ethyl methyl ether, and poly(ethylene glycol) are found on the surface simultaneously. The presence of ethoxy and methoxy end groups indicates both methoxide and ethoxide are produced and involved in the process of oligomerization. Au surfaces cycled under different electrochemical windows as model systems for Li-ion battery anodes are also examined. Interestingly, the identical oligomeric species to those found in the CEI are found on Au surfaces after running five cycles between 2.0 and 0.1 V vs Li/Li(+) in half-cells. These results show that DESI-MS provides intact molecular information on battery electrodes, enabling deeper understanding of the SEI or CEI composition. PMID:27346184

  2. Structural characterization of phospholipids by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Marto, J A; White, F M; Seldomridge, S; Marshall, A G

    1995-11-01

    Matrix-assisted laser desorption/ionization (MALDI) Fourier transform ion cyclotron resonance mass spectrometry provides for structural analysis of the principal biological phospholipids: glycerophosphatidylcholine, -ethanolamine, -serine, and -inositol. Both positive and negative molecular or quasimolecular ions are generated in high abundance. Isolated molecular ions may be collisionally activated in the source side of a dual trap mass analyzer, yielding fragments serving to identify the polar head group (positive ion mode) and fatty acid side chains (negative ion mode). Azimuthal quadrupolar excitation following collisionally activated dissociation refocuses productions close to the solenoid axis; subsequent transfer of product ions to the analyzer ion trap allows for high-resolution mass analysis. Cyro-cooling of the sample probe with liquid nitrogen greatly reduces matrix adduction encountered in the negative ion mode. PMID:8633761

  3. [Adsorption-desorption Characteristics of Fermented Rice Husk for Ferrous and Sulfur Ions].

    PubMed

    Xie, Xiao-mei; Liao, Min; Hua, Jia-yuan; Chen, Na; Zhang, Nan; Xu, Pei-zhi; Xie Kai-zhi; XU, Chang-xu; Liu, Guang-rong

    2015-10-01

    To understand the potential of rice husk to fix Fe2+ and S2- ions, the sorption of Fe2+ and S2- by fermented rice husk was studied by using batch incubation experiments in the present study. The effects of adsorption time, Fe2+ and S2- concentration, pH, the temperature and ionic strength in adsorption reaction solution on the sorption were investigated. Therefore, the stability of Fe2+ and S2- adsorbed by fermented rice husk was further validated by desorption experiments performed under similar conditions as adsorption. The results showed that, the adsorption kinetics of Fe2+ (r = 0.912 1) and S2- (r = 0.901 1) by fermented rice husk fits the Elovich kinetics equation, and Freundlich isotherm model could simulate the isotherm adsorption processes of Fe2+ (R2 = 0.965 1) and S2- (R2 = 0.936 6) on fermented rice husk was better than other models. The adsorption processes on fermented rice husk were non- preferential adsorption for Fe2+ and S2, while the adsorption process of Fe2+ on fermented rice husk was spontaneous reaction and the adsorption process of S2- was non-spontaneous reaction. The adsorption processes of Fe2+ and S2- on fermented rice husk were endothermic process since high temperature could benefit to the adsorption. The adsorption mechanism of Fe2+ on fermented rice husk was mainly controlled by coordination adsorption, the adsorption mechanism of S2- on fermented rice husk was mainly controlled by ligand exchange adsorption. The adsorption processes of Fe2+ and S2- on fermented rice husk showed greater pH adaptability which ranged from 1.50 to 11.50. With the increasing of ionic strength, the amount of adsorbed Fe2+ on fermented rice husk wasincreased in some extent, the amount of adsorbed S2- on fermented rice husk was slightly decreased, which further proved the adsorption of Fe2+ was major in inner sphere complexation and the adsorption of S2- was major in outer complexation. The desorption rates of Fe2+ and S2- which was adsorbed by fermented

  4. Optimized thermal desorption for improved sensitivity in trace explosives detection by ion mobility spectrometry.

    PubMed

    Najarro, Marcela; Dávila Morris, Melissa E; Staymates, Matthew E; Fletcher, Robert; Gillen, Greg

    2012-06-01

    In this work we evaluate the influence of thermal desorber temperature on the analytical response of a swipe-based thermal desorption ion mobility spectrometer (IMS) for detection of trace explosives. IMS response for several common high explosives ranging from 0.1 ng to 100 ng was measured over a thermal desorber temperature range from 60 °C to 280 °C. Most of the explosives examined demonstrated a well-defined maximum IMS signal response at a temperature slightly below the melting point. Optimal temperatures, giving the highest IMS peak intensity, were 80 °C for trinitrotoluene (TNT), 100 °C for pentaerythritol tetranitrate (PETN), 160 °C for cyclotrimethylenetrinitramine (RDX) and 200 °C for cyclotetramethylenetetranitramine (HMX). By modifying the desorber temperature, we were able to increase cumulative IMS signal by a factor of 5 for TNT and HMX, and by a factor of 10 for RDX and PETN. Similar signal enhancements were observed for the same compounds formulated as plastic-bonded explosives (Composition 4 (C-4), Detasheet, and Semtex). In addition, mixtures of the explosives exhibited similar enhancements in analyte peak intensities. The increases in sensitivity were obtained at the expense of increased analysis times of up to 20 seconds. A slow sample heating rate as well as slower vapor-phase analyte introduction rate caused by low-temperature desorption enhanced the analytical sensitivity of individual explosives, plastic-bonded explosives, and explosives mixtures by IMS. Several possible mechanisms that can affect IMS signal response were investigated such as thermal degradation of the analytes, ionization efficiency, competitive ionization from background, and aerosol emission. PMID:22498665

  5. Enhanced capabilities for imaging gangliosides in murine brain with matrix-assisted laser desorption/ionization and desorption electrospray ionization mass spectrometry coupled to ion mobility separation.

    PubMed

    Škrášková, Karolina; Claude, Emmanuelle; Jones, Emrys A; Towers, Mark; Ellis, Shane R; Heeren, Ron M A

    2016-07-15

    The increased interest in lipidomics calls for improved yet simplified methods of lipid analysis. Over the past two decades, mass spectrometry imaging (MSI) has been established as a powerful technique for the analysis of molecular distribution of a variety of compounds across tissue surfaces. Matrix-assisted laser desorption/ionization (MALDI) MSI is widely used to study the spatial distribution of common lipids. However, a thorough sample preparation and necessity of vacuum for efficient ionization might hamper its use for high-throughput lipid analysis. Desorption electrospray ionization (DESI) is a relatively young MS technique. In DESI, ionization of molecules occurs under ambient conditions, which alleviates sample preparation. Moreover, DESI does not require the application of an external matrix, making the detection of low mass species more feasible due to the lack of chemical matrix background. However, irrespective of the ionization method, the final information obtained during an MSI experiment is very complex and its analysis becomes challenging. It was shown that coupling MSI to ion mobility separation (IMS) simplifies imaging data interpretation. Here we employed DESI and MALDI MSI for a lipidomic analysis of the murine brain using the same IMS-enabled instrument. We report for the first time on the DESI IMS-MSI of multiply sialylated ganglioside species, as well as their acetylated versions, which we detected directly from the murine brain tissue. We show that poly-sialylated gangliosides can be imaged as multiply charged ions using DESI, while they are clearly separated from the rest of the lipid classes based on their charge state using ion mobility. This represents a major improvement in MSI of intact fragile lipid species. We additionally show that complementary lipid information is reached under particular conditions when DESI is compared to MALDI MSI. PMID:26922843

  6. Detection of native protein ions in aqueous solution under ambient conditions by electrospray laser desorption/ionization mass spectrometry.

    PubMed

    Shiea, Jentaie; Yuan, Cheng-Hui; Huang, Min-Zong; Cheng, Sy-Chyi; Ma, Ya-Lin; Tseng, Wei-Lung; Chang, Hui-Chiu; Hung, Wen-Chun

    2008-07-01

    Liquid electrospray laser desorption/ionization (ELDI) mass spectrometry allows desorption and ionization of proteins directly from aqueous solutions and biological fluids under ambient conditions. Native protein ions such as those of myoglobin, cytochrome c, and hemoglobin were obtained. A droplet (ca. 5 microL) containing the protein molecules and micrometer-sized particles (e.g., carbon graphite powder) is irradiated with a pulsed UV laser. The laser energy adsorbed by the inert particles is transferred to the surrounding solvent and protein molecules, leading to their desorption; the desorbed gaseous molecules are then postionized within an electrospray (ESI) plume to generate the ESI-like protein ions. With the use of this technique, we detected only the protonated protein ions in various biological fluids (including human tears, cow milk, serum, and bacterial extracts) without interference from their corresponding sodiated or potassiated adduct ions. In addition, we rapidly quantified the levels of glycosylated hemoglobin present in drops of whole blood obtained from diabetic patients without the need of sample pretreatment. PMID:18510347

  7. Ion-to-Neutral Ratios and Thermal Proton Transfer in Matrix-Assisted Laser Desorption/Ionization.

    PubMed

    Lu, I-Chung; Chu, Kuan Yu; Lin, Chih-Yuan; Wu, Shang-Yun; Dyakov, Yuri A; Chen, Jien-Lian; Gray-Weale, Angus; Lee, Yuan-Tseh; Ni, Chi-Kung

    2015-07-01

    The ion-to-neutral ratios of four commonly used solid matrices, α-cyano-4-hydroxycinnamic acid (CHCA), 2,5-dihydroxybenzoic acid (2,5-DHB), sinapinic acid (SA), and ferulic acid (FA) in matrix-assisted laser desorption/ionization (MALDI) at 355 nm are reported. Ions are measured using a time-of-flight mass spectrometer combined with a time-sliced ion imaging detector. Neutrals are measured using a rotatable quadrupole mass spectrometer. The ion-to-neutral ratios of CHCA are three orders of magnitude larger than those of the other matrices at the same laser fluence. The ion-to-neutral ratios predicted using the thermal proton transfer model are similar to the experimental measurements, indicating that thermal proton transfer reactions play a major role in generating ions in ultraviolet-MALDI. PMID:25851654

  8. Ion-to-Neutral Ratios and Thermal Proton Transfer in Matrix-Assisted Laser Desorption/Ionization

    NASA Astrophysics Data System (ADS)

    Lu, I.-Chung; Chu, Kuan Yu; Lin, Chih-Yuan; Wu, Shang-Yun; Dyakov, Yuri A.; Chen, Jien-Lian; Gray-Weale, Angus; Lee, Yuan-Tseh; Ni, Chi-Kung

    2015-07-01

    The ion-to-neutral ratios of four commonly used solid matrices, α-cyano-4-hydroxycinnamic acid (CHCA), 2,5-dihydroxybenzoic acid (2,5-DHB), sinapinic acid (SA), and ferulic acid (FA) in matrix-assisted laser desorption/ionization (MALDI) at 355 nm are reported. Ions are measured using a time-of-flight mass spectrometer combined with a time-sliced ion imaging detector. Neutrals are measured using a rotatable quadrupole mass spectrometer. The ion-to-neutral ratios of CHCA are three orders of magnitude larger than those of the other matrices at the same laser fluence. The ion-to-neutral ratios predicted using the thermal proton transfer model are similar to the experimental measurements, indicating that thermal proton transfer reactions play a major role in generating ions in ultraviolet-MALDI.

  9. The dissociation kinetics of NO on Rh(111) as studied by temperature programmed static secondary ion mass spectrometry and desorption

    NASA Astrophysics Data System (ADS)

    Borg, H. J.; Reijerse, J. F. C.-J. M.; van Santen, R. A.; Niemantsverdriet, J. W.

    1994-12-01

    Temperature programmed static secondary ion mass spectrometry (TPSSIMS) and temperature programmed desorption (TPD) have been used to study the kinetics of adsorption, dissociation, and desorption of NO on Rh(111). At 100 K, NO adsorption is molecular and proceeds via mobile precursor state kinetics with a high initial sticking probability. SSIMS indicates the presence of two distinct NO adsorption states, indicative of threefold adsorption at low coverage, and occupation of bridge sites at higher coverages. Three characteristic coverage regimes appear with respect to NO dissociation. At low coverages θNO<0.25 ML, NO dissociates completely at temperatures between 275 and 340 K. If we neglect lateral interactions and assume pure first order dissociation kinetics, we find effective values for the activation barrier and preexponential factor of 40±6 kJ/mol and 106±1 s-1 for the dissociation of 0.15-0.20 ML NO. However, if we assume that a NO molecule needs an ensemble of three to four vacant sites in order to dissociate, the preexponential factor and activation energy are ˜1011 s-1 and 65 kJ/mol, in better agreement with transition state theory expectations. The Nads and Oads dissociation products desorb as N2 and O2, respectively, with desorption parameters Edes=118±10 kJ/mol and νdes=1010.1±1.0 s-1 for N2 in the zero coverage limit. At higher coverages, the desorption kinetics of N2 is strongly influenced by the presence of coadsorbed oxygen. In the medium coverage range 0.25<θNO<0.50 ML, part of the NO desorbs molecularly, with an estimated desorption barrier of 113±10 kJ/mol and a preexponential of 1013.5±1.0 s-1. Dissociation of NO becomes progressively inhibited due to site blocking, the onset shifting from 275 K at 0.25 ML to 400 K, coinciding with the NO desorption temperature, at a coverage of 0.50 ML. The accumulation of nitrogen and oxygen atoms on the highly covered surface causes a destabilization of the nitrogen atoms, which results in an

  10. Site-Specific Carbon Isotopes in Organics

    NASA Astrophysics Data System (ADS)

    Piasecki, A.; Eiler, J. M.

    2012-12-01

    Natural organic molecules exhibit a wide range of internal site-specific isotope variation (i.e., molecules with same isotopic substitution type but different site). Such variations are generally unconstrained by bulk isotopic measurements. If known, site-specific variations might constrain temperatures of equilibrium, mechanisms of formation or consumption reactions, and possibly other details. For example, lipids can exhibit carbon isotope differences of up to 30‰ between adjacent carbon sites as a result of fractionations arising during decarboxylation of pyruvate and other steps in lipid biosynthesis(1). We present a method for site-specific carbon isotope analysis of propane, based on high-resolution, multi-collector gas source mass spectrometry, using a novel prototype instrument - the Thermo MAT 253 Ultra. This machine has an inlet system and electron bombardment ion source resembling those in conventional stable isotope gas source mass spectrometers, and the energy filter, magnet, and detector array resembling those in multi-collector ICPMS and TIMS. The detector array has 7 detector positions, 6 of which are movable, and each of which can collect ions with either a faraday cup (read through amplifiers ranging from 107-1012 ohms) or an SEM. High mass resolving power (up to 27,000, MRP = M/dM definition) is achieved through a narrow entrance slit, adjustable from 250 to 5 μm. Such resolution can cleanly separate isobaric interferences between isotopologues of organic molecules having the same cardinal mass (e.g., 13CH3 and 12CH2D). We use this technology to analyze the isotopologues and fragments of propane, and use such data to solve for the site-specific carbon isotope fractionation. By measuring isotopologues of both the one-carbon (13CH3) and the two-carbon (13C12CH4) fragment ion, we can solve for both bulk δ13C and the difference in δ13C between the terminal and central carbon position. We tested this method by analyzing mixtures between natural

  11. Adsorption and Desorption of Nickel(II) Ions from Aqueous Solution by a Lignocellulose/Montmorillonite Nanocomposite

    PubMed Central

    Zhang, Xiaotao; Wang, Ximing

    2015-01-01

    A new and inexpensive lignocellulose/montmorillonite (LNC/MMT) nanocomposite was prepared by a chemical intercalation of LNC into MMT and was subsequently investigated as an adsorbent in batch systems for the adsorption-desorption of Ni(II) ions in an aqueous solution. The optimum conditions for the Ni(II) ion adsorption capacity of the LNC/MMT nanocomposite were studied in detail by varying parameters such as the initial Ni(II) concentration, the solution pH value, the adsorption temperature and time. The results indicated that the maximum adsorption capacity of Ni(II) reached 94.86 mg/g at an initial Ni(II) concentration of 0.0032 mol/L, a solution pH of 6.8, an adsorption temperature of 70°C, and adsorption time of 40 min. The represented adsorption kinetics model exhibited good agreement between the experimental data and the pseudo-second-order kinetic model. The Langmuir isotherm equation best fit the experimental data. The structure of the LNC/MMT nanocomposite was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), whereas the adsorption mechanism was discussed in combination with the results obtained from scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy analyses (FTIR). The desorption capacity of the LNC/MMT nanocomposite depended on parameters such as HNO3 concentration, desorption temperature, and desorption time. The satisfactory desorption capacity of 81.34 mg/g was obtained at a HNO3 concentration, desorption temperature, and desorption time of 0.2 mol/L, 60 ºC, and 30 min, respectively. The regeneration studies showed that the adsorption capacity of the LNC/MMT nanocomposite was consistent for five cycles without any appreciable loss in the batch process and confirmed that the LNC/MMT nanocomposite was reusable. The overall study revealed that the LNC/MMT nanocomposite functioned as an effective adsorbent in the detoxification of Ni

  12. Effects of matrix structure/acidity on ion formation in matrix-assisted laser desorption ionization mass spectrometry

    SciTech Connect

    Gimon-Kinsel, M.; Preston-Schaffter, L.M.; Kinsel, G.R.; Russell, D.H.

    1997-03-12

    The involvement of ground and excited state proton transfer reactions in matrix-assisted laser desorption ionization (MALDI) of bradykinin and bovine insulin is examined using a series of p-substituted aniline compounds as matrices. Semiempirical calculations of ground and excited state acidity of the p-substituted aniline and anilinium ions are presented. A linear correlation between log (analyte [A + H]{sup +} ion yield) and matrix acidity is obtained. The behavior of the seven p-substituted anilines is discussed in terms of the relationship between matrix compound structure, reactivity, and ability to act as a MALDI matrix. 44 refs., 4 figs., 5 tabs.

  13. A new approach for detection of explosives based on ion mobility spectrometry and laser desorption/ionization on porous silicon

    NASA Astrophysics Data System (ADS)

    Kuzishchin, Yury; Kotkovskii, Gennadii; Martynov, Igor; Dovzhenko, Dmitriy; Chistyakov, Alexander

    2016-05-01

    We demonstrate a new way for detection ultralow concentration of explosives in this study. It combines an ion mobility spectrometry (IMS) and a promising method of laser desorption/ionization on silicon (DIOS). The DIOS is widely used in mass spectrometry due to the possibility of small molecule detection and high sensitivity. It is known that IMS based on laser ion source is a power method for the fast detection of ultralow concentration of organic molecules. However requirement of using high energy pulse ultraviolet laser increases weight and size of the device. The use of DIOS in an ion source of IMS could decrease energy pulse requirements and allows one to construct both compact and high sensitive device for analyzing gas and liquid probes. On the other hand mechanisms of DIOS in gas media is poorly studied, especially in case of nitroaromatic compounds. The investigation of the desorption/ionization on porous silicon (pSi) surface of nitroaromatic compounds has been carried out for 2,4,6-trinitrotoluene (TNT) using IMS and mass spectrometry (MS). It has been demonstrated that TNT ion formation in a gas medium is a complicated process and includes both an electron emission from the pSi surface with subsequent ion-molecular reactions in a gas phase and a proton transfer between pSi surface and TNT molecule.

  14. Study of tritium desorption by energetic ion bombardment from tungsten material

    NASA Astrophysics Data System (ADS)

    Kato, Shuichi; Ito, Atsushi M.; Takayama, Arimichi; Sasao, Mamiko; Wada, Motoi; Nakamura, Hiroaki

    2016-01-01

    To solve the problem of tritium retention in a nuclear fusion reactor, the removal of hydrogen isotopes retained in a tungsten material by exposure to the other hydrogen isotope plasma was investigated. We proposed the balance equation between the absorption and desorption of the hydrogen isotope atoms in the tungsten material. Absorption ratio and desorption yield were calculated by binary collision approximation simulation. Simulation results showed that desorption yield was proportional to the concentration of the retained hydrogen isotope. Therefore, the decrease in the retained hydrogen isotope atoms by hydrogen plasma irradiation can be regarded as approximately exponential decay. The decay rate in the case that retained deuterium atoms are removed by light hydrogen irradiation was two thirds of the decay rate in the case that retained tritium atoms are removed by deuterium irradiation.

  15. Thermal desorption behavior of deuterium for 6 MeV Fe ion irradiated W with various damage concentrations

    NASA Astrophysics Data System (ADS)

    Oya, Yasuhisa; Li, Xiaochun; Sato, Misaki; Yuyama, Kenta; Zhang, Long; Kondo, Sosuke; Hinoki, Tatsuya; Hatano, Yuji; Watanabe, Hideo; Yoshida, Naoaki; Chikada, Takumi

    2015-06-01

    W samples were irradiated at 300 K with 6 MeV Fe ion with damage concentrations in the range from 0.0003 to 1.0 displacements per atom (dpa) and then implanted at 300 K with 500 eV D ions to a fluence of 5 × 1021 D/m2. Deuterium retention in the damaged samples was examined in situ by thermal desorption spectrometry (TDS). Simulation of the TDS spectra was performed using the Hydrogen Isotope Diffusion and Trapping (HIDT) simulation code to reveal the binding energies for deuterium captured by the ion-induced defects. It has been shown that the deuterium TDS spectra consist of two or three peaks (depending on the damage concentration) at about 400, 600 and 800 K, and can be simulated by the HIDT simulation code with the use of hydrogen-trap binding energies of 0.65, 1.25, and 1.55 eV.

  16. Roxarsone desorption from the surface of goethite by competitive anions, phosphate and hydroxide ions: Significance of the presence of metal ions.

    PubMed

    Wang, Ling-Yuan; Wang, Shao-Wei; Chen, Wan-Ru

    2016-06-01

    Aromatic organoarsenical roxarsone (ROX) is a common additive for livestock feed. This arsenic containing pollutant could be discharged into the environment through agricultural application of animal manure, and pose potential threats to both humans and the wider environment. In this study, the influence of pH, competing anions and metal ions on the adsorption and desorption of ROX on goethite were investigated in order to understand their mobility in the environment. Both hydroxide ions and phosphate are common substances in the environment, and both are potential competing anions for ROX. Our results showed the addition of phosphate desorbed more ROX than the addition of hydroxide ions. As pH increased, the effect of phosphate did not show much difference to that of hydroxide ion. The results indicate that the presence of phosphate will greatly increase the mobility of ROX at low pH. Six common metal ions, including Zn(2+), Cu(2+), Fe(3+), Mn(2+), Mg(2+), and Ca(2+), were tested and all spiked metal ions enhanced the stability of ROX adsorption on the surface of goethite, and led to less desorption when phosphate was added. The results demonstrate that metal ions may form complex/surface precipitation with ROX to enhance its adsorption. The effect from Fe(3+), Zn(2+) and Cu(2+) was more pronounced than other metal ions, which might result from the fact that these three metal ions tend to associate with hydroxide ions and decrease the pH. The results of this research may shed light on the environmental fate and transportation of aromatic organoarsenicals in soil. PMID:26999752

  17. Automated ambient desorption-ionization platform for surface imaging integrated with a commercial Fourier transform ion cyclotron resonance mass spectrometer.

    PubMed

    Pól, Jaroslav; Vidová, Veronika; Kruppa, Gary; Kobliha, Václav; Novák, Petr; Lemr, Karel; Kotiaho, Tapio; Kostiainen, Risto; Havlícek, Vladimír; Volný, Michael

    2009-10-15

    A fully automated atmospheric pressure ionization platform has been built and coupled with a commercial high-resolution Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS) instrument. The outstanding performance of this instrument allowed screening on the basis of exact masses in imaging mode. The main novel aspect was in the integration of the atmospheric pressure ionization imaging into the current software for matrix-assisted laser desorption ionization (MALDI) imaging, which allows the user of this commercial dual-source mass spectrometer to perform MALDI-MS and different ambient MS imaging from the same user interface and to utilize the same software tools. Desorption electrospray ionization (DESI) and desorption atmospheric pressure photoionization (DAPPI) were chosen to test the ambient surface imaging capabilities of this new ionization platform. Results of DESI imaging experiments performed on brain tissue sections are in agreement with previous MS imaging reports obtained by DESI imaging, but due to the high resolution and mass accuracy of the FTICR instrument it was possible to resolve several ions at the same nominal mass in the DESI-MS spectra of brain tissue. These isobaric interferences at low resolution are due to the overlap of ions from different lipid classes with different biological relevance. It was demonstrated that with the use of high-resolution MS fast imaging screening of lipids can be achieved without any preseparation steps. DAPPI, which is a relatively new and less developed ambient ionization technique compared to DESI, was used in imaging mode for the first time ever. It showed promise in imaging of phytocompounds from plant leaves, and selective ionization of a sterol lipid was achieved by DAPPI from a brain tissue sample. PMID:19761221

  18. Photon-stimulated desorption of F(-) ions from CF(3)Cl adsorbed on Si(111)-7x7.

    PubMed

    Wen, C-R; Chou, L-C

    2004-06-15

    We report the photon-stimulated desorption of negative ions induced by direct dipolar dissociation and dissociative electron attachment. The photon-stimulated desorption of F(-) ions from CF(3)Cl physisorbed on a Si(111)-7x7 surface at 30 K in the photon energy range 12-35 eV was studied. The F(-) ion yield exhibits four resonances, at 12.8, 16.2, 19.5, and 22.3 eV, quite unlike the gas phase photodissociation cross section. The intensities of these resonances depend strongly on the CF(3)Cl coverage in a manner which varies from peak to peak. The resonances at 19.5 and 22.3 eV, which have a significant enhancement in the monolayer regime, are due to electron mediated dipolar dissociation of adsorbed CF(3)Cl molecules. The enhancement is attributed to surface electron attachment following molecular excitation. A significant enhancement in the monolayer regime has also been observed for the resonances at 12.8 and 16.2 eV. These two resonances are ascribable to a combination of electron mediated dipolar dissociation and dissociative electron attachment driven by photoelectrons generated in the neighboring molecules. PMID:15268144

  19. Electron-ion dynamics in laser-assisted desorption of hydrogen atoms from H-Si(111) surface

    SciTech Connect

    Bubin, Sergiy; Varga, Kalman

    2011-09-15

    In the framework of real time real space time-dependent density functional theory we have studied the electron-ion dynamics of a hydrogen-terminated silicon surface H-Si(111) subjected to intense laser irradiation. Two surface fragments of different sizes have been used in the simulations. When the intensity and duration of the laser exceed certain levels (which depend on the wavelength) we observe the desorption of the hydrogen atoms, while the underlying silicon layer remains essentially undamaged. Upon further increase of the laser intensity, the chemical bonds between silicon atoms break as well. The results of the simulations suggest that with an appropriate choice of laser parameters it should be possible to remove the hydrogen layer from the H-Si(111) surface in a matter of a few tens of femtoseconds. We have also observed that at high laser field intensities (2-4 V/A in this work) the desorption occurs even when the laser frequency is smaller than the optical gap of the silicon surface fragments. Therefore, nonlinear phenomena must play an essential role in such desorption processes.

  20. Collection method for chemical particulates on surfaces with detection using thermal desorption-ion trap mass spectrometry.

    PubMed

    Ewing, K J; Gibson, D; Sanghera, J; Miklos, F

    2013-05-01

    Successful analysis of particulate/low vapor pressure analytes such as explosives and toxic chemicals, and commercial pesticides require new sampling tools that enable detection of these analytes using current vapor phase detection instruments. We describe a sampling approach that uses stainless steel screens coated with a sticky polydimethyl siloxane (PDMS) coating to capture particulates from surfaces. Preliminary results for the collection of dimethyl methylphosphonate (DMMP) sorbed onto silica gel (SG) particulates (DMMP/SG) from a surface with subsequent analysis by thermal desorption-cylindrical ion trap mass spectrometry (TD-CITMS) are reported. PMID:23601282

  1. NORMAL LOAD BEARING BY SITE SPECIFIC CANISTER

    SciTech Connect

    NA

    2005-03-23

    The overall purpose of this calculation is to perform a preliminary analysis of the Site Specific Canister/Basket, subject to static gravity loads that include the self weight of the Canister Shell, the Basket, the Spent Nuclear Fuel, the Shield Plug and the related hardware, so that the loads are approximately known for sizing purposes. Based on these loads the stress levels in various components of the Site Specific Canister/Basket are evaluated.

  2. Vitamin D-metabolites from human plasma and mass spectrometric analysis by fast heavy ion induced desorption

    NASA Astrophysics Data System (ADS)

    Fohlman, J.; Peterson, P. A.; Kamensky, I.; Håkansson, P.; Sundqvist, B.

    1982-07-01

    D-vitamin metabolites have been isolated from human serum employing chromatographic techniques. The serum carrier protein for vitamin D (DBP) was first isolated by immunosorbent chromatography. Lipid ligands associated with DBP were then extracted with hexane and separated by high pressure liquid chromatography (HPLC). Detection of vitamin D metabolites by their absorbance of ultraviolet light is not sufficiently sensitive to monitor all vitamin D derivatives from a few millilitres of serum. Therefore, further analyses are necessary to quantitate these compounds. We have begun to develop a mass spectrometric method to achieve a reliable, quantitative procedure. As a first step towards this goal a number of pure samples of vitamin D compounds have been studied in a time-of-flight mass spectrometer based on fast heavy ion induced desorption. All vitamin D compounds examined could be detected and identified by their molecular ion and fragment spectra.

  3. Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides

    NASA Astrophysics Data System (ADS)

    McMillen, Chelsea L.; Wright, Patience M.; Cassady, Carolyn J.

    2016-05-01

    Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides.

  4. Laser mass spectrometry of biological molecular ions produced by matrix assisted laser desorption ionization (MALDI)

    NASA Astrophysics Data System (ADS)

    Jia, W. J.; Kosmidis, C.; Ledingham, K. W. D.; Scott, C. T. J.; Singhal, R. P.

    1996-10-01

    A tandem reflectron laser mass spectrometer is used for investigations of the photo fragmentation of molecular ions. The observed fragmentation patterns for 2,5-dihydrobenzoic acid and its fragments ions are analysed. PTH-trytophan and PTH-valine ions, generated by MALDI, are photodissociated and their fragmentation pattern is discussed.

  5. Thermodynamic basis of site-specific cooperativity.

    PubMed

    Di Cera, E

    1994-08-01

    Cooperative phenomena in biological macromolecules arise from the interaction of many distinct subsystems, such as structural domains or binding sites. Cooperative properties of the system as a whole, like protein folding or allosteric transitions, are subject to the restrictions imposed by thermodynamic stability. These restrictions, however, do not apply in the case of individual subsystems open to interactions with the rest of the macromolecule. The site-specific properties of such subsystems can be understood in general thermodynamic terms from those of a multicomponent system under particular conditions. The analogy provides a thermodynamic basis for site-specific cooperativity. PMID:8075382

  6. DOE site-specific threat assessment

    SciTech Connect

    West, D.J.; Al-Ayat, R.A.; Judd, B.R.

    1985-07-12

    A facility manager faced with the challenges of protecting a nuclear facility against potential threats must consider the likelihood and consequences of such threats, know the capabilities of the facility safeguards and security systems, and make informed decisions about the cost-effectivness of safeguards and security upgrades. To help meet these challenges, the San Francisco Operations Office of the Department of Energy, in conjunction with the Lawrence Livermore Laboratory, has developed a site-specific threat assessment approach and a quantitative model to improve the quality and consistency of site-specific threat assessment and resultant security upgrade decisions at sensitive Department of Energy facilities. 5 figs.

  7. Site-Specific Infrared Probes of Proteins

    PubMed Central

    Ma, Jianqiang; Pazos, Ileana M.; Zhang, Wenkai; Culik, Robert M.; Gai, Feng

    2015-01-01

    Infrared spectroscopy has played an instrumental role in studying a wide variety of biological questions. However, in many cases it is impossible or difficult to rely on the intrinsic vibrational modes of biological molecules of interest, such as proteins, to reveal structural and/or environmental information in a site-specific manner. To overcome this limitation, many recent efforts have been dedicated to the development and application of various extrinsic vibrational probes that can be incorporated into biological molecules and used to site-specifically interrogate their structural and/or environmental properties. In this Review, we highlight some recent advancements of this rapidly growing research area. PMID:25580624

  8. Matrix-assisted laser desorption using a fast-atom bombardment ion source and a magnetic mass spectrometer.

    PubMed

    Annan, R S; Köchling, H J; Hill, J A; Biemann, K

    1992-04-01

    A conventional fast-atom bombardment (FAB) ion source was used to achieve matrix-assisted laser desorption (MALD) in a high-mass, double-focusing, magnetic mass spectrometer. The pulsed ion signals generated by irradiation of a mixture of sample and matrix (2,5-dihydroxybenzoic acid) with either a XeF excimer laser (353 nm) or a nitrogen laser (337 nm) were recorded with a focal-plane detector. A resolution (full-width at half maximum) of 4500 was achieved at m/z 1347.7 (the peptide substance P), 2500 for CsI cluster ions at m/z 10,005.7, and 1250 for the isotope cluster of the small protein cytochrome c (horse) [M+H]+ = m/z 12,360 (average). Sensitivity is demonstrated with 11 fmol of substance P. A survey scan is taken to locate the m/z of the sample molecular ion. The segment that contains the sample can then be integrated for a longer time to produce a better signal-to-noise ratio. In addition to higher sensitivity and lower matrix interference, the advantage of MALD over FAB is the former's lower susceptibility to the presence of salts, and competition between hydrophobic and hydrophilic components of a mixture. This feature is demonstrated by the complete MALD spectrum of a crude partial tryptic digest of sperm-whale apomyoglobin, containing 24 peptides, representing the entire sequence of this protein. PMID:1373978

  9. Matrix-free mass spectrometric imaging using laser desorption ionisation Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Goodwin, Richard J A; Pitt, Andrew R; Harrison, David; Weidt, Stefan K; Langridge-Smith, Pat R R; Barrett, Michael P; Logan Mackay, C

    2011-04-15

    Mass spectrometry imaging (MSI) is a powerful tool in metabolomics and proteomics for the spatial localization and identification of pharmaceuticals, metabolites, lipids, peptides and proteins in biological tissues. However, sample preparation remains a crucial variable in obtaining the most accurate distributions. Common washing steps used to remove salts, and solvent-based matrix application, allow analyte spreading to occur. Solvent-free matrix applications can reduce this risk, but increase the possibility of ionisation bias due to matrix adhesion to tissue sections. We report here the use of matrix-free MSI using laser desorption ionisation performed on a 12 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. We used unprocessed tissue with no post-processing following thaw-mounting on matrix-assisted laser desorption ionisation (MALDI) indium-tin oxide (ITO) target plates. The identification and distribution of a range of phospholipids in mouse brain and kidney sections are presented and compared with previously published MALDI time-of-flight (TOF) MSI distributions. PMID:21416534

  10. Critical evaluation of adsorption-desorption hysteresis of heavy metal ions from carbon nanotubes: influence of wall number and surface functionalization.

    PubMed

    Li, Jie; Chen, Changlun; Zhang, Shouwei; Ren, Xuemei; Tan, Xiaoli; Wang, Xiangke

    2014-04-01

    Single-, double-, and multi-walled carbon nanotubes (SWCNTs, DWCNTs, and MWCNTs), and two oxidized MWCNTs with different oxygen contents (2.51 wt % and 3.5 wt %) were used to study the effect of the wall number and surface functionalization of CNTs on their adsorption capacity and adsorption-desorption hysteresis for heavy metal ions (Ni(II), Cd(II), and Pb(II)). Metal ions adsorbed on CNTs could be desorbed by lowering the solution pH. Adsoprtion of heavy metal ions was not completely reversible when the supernatant was replaced with metal ion-free electrolyte solution. With increasing wall number and amount of surface functional groups, CNTs had more surface defects and exhibited higher adsorption capacity and higher adsorption-desorption hysteresis index (HI) values. The coverage of heavy metal ions on the surface of CNTs, solution pH, and temperature affect the metal ion adsorption-desorption hysteresis. A possible shift in the adsorption mechanism from mainly irreversible to largely reversible processes may take place, as the amount of metal ions adsorbed on CNTs increases. Heavy metal ions may be irreversibly adsorbed on defect sites. PMID:24488899

  11. Rapid analysis of animal drug residues by microcolumn solid-phase extraction and thermal desorption-ion trap mass spectrometry

    SciTech Connect

    Barshick, S.A.; Buchanan, M.V.

    1994-11-01

    A new approach was developed for the rapid and quantitative determination of an anthelmintic drug, phenothiazine, in milk. The technique involves a simple extraction procedure using a C{sub 18} microcolumn disc, followed by thermal desorption of the analyte from the disc directly into an ion trap mass spectrometer. The compounds are selectively ionized by isobutane chemical ionization and detected by tandem mass spectrometry. With this approach, 10 ppb detection limits were achieved with as little as 100 {mu}L mild and only 10 min of analysis time. This approach was used to analyze samples of milk taken from a cow administered a one-time therapeutic dose of phenothiazine. The target compound could be detected at 56 post-dosage, corresponding to a concentration of 30 ppb. 13 refs., 3 figs., 2 tabs.

  12. Nanoparticles for Site Specific Genome Editing

    NASA Astrophysics Data System (ADS)

    McNeer, Nicole Ali

    Triplex-forming peptide nucleic acids (PNAs) can be used to coordinate the recombination of short 50-60 by "donor DNA" fragments into genomic DNA, resulting in site-specific correction of genetic mutations or the introduction of advantageous genetic modifications. Site-specific gene editing in hematopoietic stem and progenitor cells (HSPCs) could result in treatment or cure of inherited disorders of the blood such as beta-thalassemia. Gene editing in HSPCs and differentiated T cells could help combat HIV/AIDs by modifying receptors, such as CCR5, necessary for R5-tropic HIV entry. However, translation of genome modification technologies to clinical practice is limited by challenges in intracellular delivery, especially in difficult-to-transfect hematolymphoid cells. In vivo gene editing could also provide novel treatment for systemic monogenic disorders such as cystic fibrosis, an autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane receptor. Here, we have engineered biodegradable nanoparticles to deliver oligonucleotides for site-specific genome editing of disease-relevant genes in human cells, with high efficiency, low toxicity, and editing of clinically relevant cell types. We designed nanoparticles to edit the human beta-globin and CCR5 genes in hematopoietic cells. We show that poly(lactic-co-glycolic acid) (PLGA) nanoparticles can delivery PNA and donor DNA for site-specific gene modification in human hematopoietic cells in vitro and in vivo in NOD-scid IL2rgammanull mice. Nanoparticles delivered by tail vein localized to hematopoietic compartments in the spleen and bone marrow of humanized mice, resulting in modification of the beta-globin and CCR5 genes. Modification frequencies ranged from 0.005 to 20% of cells depending on the organ and cell type, without detectable toxicity. This project developed highly versatile methods for delivery of therapeutics to hematolymphoid cells and hematopoietic stem cells, and will help to

  13. Transposon-specified site-specific recombination.

    PubMed Central

    Kitts, P; Symington, L; Burke, M; Reed, R; Sherratt, D

    1982-01-01

    Cointegrate DNA molecules containing two copies of a transposable element appear to be intermediates in the transposition process. These structures are resolved by site-specific recombination to yield the normal end products of transposition. The transposable element gamma delta (Tn1000) synthesizes a product interchangeable with the Tn1/3tnpR protein in promoting Tn1/3 site-specific recombination. These data support the hypothesis that cointegrates containing directly repeated copies of Tn1/3 are obligatory intermediates in interreplicon transposition of Tn1/3. In addition, we show here that the reaction is independent of the element-encoded tnpA gene product. Tn501, which specifies mercury resistance, also produces cointegrates as intermediates in interreplicon transposition. The appearance of Tn501-specified recombination activity that can act on these cointegrates requires growth of cells in the presence of Hg2+. Images PMID:6275390

  14. Site-Specific PEGylation of Therapeutic Proteins

    PubMed Central

    Dozier, Jonathan K.; Distefano, Mark D.

    2015-01-01

    The use of proteins as therapeutics has a long history and is becoming ever more common in modern medicine. While the number of protein-based drugs is growing every year, significant problems still remain with their use. Among these problems are rapid degradation and excretion from patients, thus requiring frequent dosing, which in turn increases the chances for an immunological response as well as increasing the cost of therapy. One of the main strategies to alleviate these problems is to link a polyethylene glycol (PEG) group to the protein of interest. This process, called PEGylation, has grown dramatically in recent years resulting in several approved drugs. Installing a single PEG chain at a defined site in a protein is challenging. Recently, there is has been considerable research into various methods for the site-specific PEGylation of proteins. This review seeks to summarize that work and provide background and context for how site-specific PEGylation is performed. After introducing the topic of site-specific PEGylation, recent developments using chemical methods are described. That is followed by a more extensive discussion of bioorthogonal reactions and enzymatic labeling. PMID:26516849

  15. The roles of electronic and nuclear stopping in the desorption valine negative molecular ions

    SciTech Connect

    Hunt, J.E.; Salehpour, M.; Fishel, D.L.; Tou, J.C.

    1988-01-01

    The yield of valine negative molecular ions has been measured as a function of Xe/sup +/, Kr/sup +/, and Ar/sup +/ primary ion velocity. The electronic and nuclear stopping powers are comparable in magnitude and opposite in slope in the experimental velocity region. The yield data are explained in terms of electronic stopping power alone, with no contribution from nuclear stopping power within the experimental error. Low molecular weight atomic species are found to be best described by a nuclear stopping power related process. 18 refs., 3 figs.

  16. Sorption and desorption of Cr(VI) ions from water by biochars in different environmental conditions.

    PubMed

    Tytłak, Aleksandra; Oleszczuk, Patryk; Dobrowolski, Ryszard

    2015-04-01

    In the present research, the potential of two biochars produced by the thermal decomposition of wheat straw (BCS) and wicker (BCW) for Cr(VI) ions removing from wastewater was investigated. The pH and the presence of chlorides and nitrates were also investigated. The Freundlich and Langmuir models were applied for the characterization of adsorption isotherms. The Langmuir model has better fitting of adsorption isotherms than the Freundlich model. The sorption process can be described by the pseudo second-order equation. The optimal adsorption capacities were obtained at pH 2 and were 24.6 and 23.6 mg/g for BCS and BCW, respectively. X-ray photoelectron spectroscopy (XPS) studies confirmed that Cr(III) ions were the most abundant chromium species on the biochars' surface. The results indicated that the sorption mechanism of Cr(VI) on biochar involves anionic and cationic adsorption combined with Cr(VI) species reduction. PMID:25378029

  17. Laser desorption-ion mobility spectrometry as a useful tool for imaging of thin layer chromatography surface.

    PubMed

    Ilbeigi, Vahideh; Sabo, Martin; Valadbeigi, Younes; Matejcik, Stefan; Tabrizchi, Mahmoud

    2016-08-12

    We present a novel method for coupling thin layer chromatography (TLC) with ion mobility spectrometry (IMS) using laser desorption technique (LD). After separation of the compounds by TLC, the TLC surface was sampled by the LD-IMS without any further manipulation or preparation. The position of the laser was fixed and the TLC plate was moved in desired directions by the motorized micro-positioning stage. The method was successfully applied to analyze the TLC plates containing explosives (tri nitro toluene, 1,3,5-trinitro- 1,3,5-triazacyclohexane, pentaerythritol tetranitrate, 2,4-dinitro toluene and 3,4-dinitro toluene), amino acids (alanine, proline and isoleucine), nicotine and diphenylamine mixtures and detection limits for these compounds were determined. Combination of TLC with LD-IMS technique offers additional separation dimension, allowing separation of overlapping TLC analytes. The time for TLC sampling by LD-IMS was less than 80s. The scan rate for LD is adjustable so that fast and effective analysis of the mixtures is possible with the proposed method. PMID:27397925

  18. Vacuum compatible sample positioning device for matrix assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry imaging

    PubMed Central

    Aizikov, Konstantin; Smith, Donald F.; Chargin, David A.; Ivanov, Sergei; Lin, Tzu-Yung; Heeren, Ron M. A.; O’Connor, Peter B.

    2011-01-01

    The high mass accuracy and resolving power of Fourier transform ion cyclotron resonance mass spectrometers (FT-ICR MS) make them ideal mass detectors for mass spectrometry imaging (MSI), promising to provide unmatched molecular resolution capabilities. The intrinsic low tolerance of FT-ICR MS to RF interference, however, along with typically vertical positioning of the sample, and MSI acquisition speed requirements present numerous engineering challenges in creating robotics capable of achieving the spatial resolution to match. This work discusses a two-dimensional positioning stage designed to address these issues. The stage is capable of operating in ∼1 × 10–8 mbar vacuum. The range of motion is set to 100 mm × 100 mm to accommodate large samples, while the positioning accuracy is demonstrated to be less than 0.4 micron in both directions under vertical load over the entire range. This device was integrated into three different matrix assisted laser desorption/ionization (MALDI) FT-ICR instruments and showed no detectable RF noise. The “oversampling” MALDI-MSI experiments, under which the sample is completely ablated at each position, followed by the target movement of the distance smaller than the laser beam, conducted on the custom-built 7T FT-ICR MS demonstrate the stability and positional accuracy of the stage robotics which delivers high spatial resolution mass spectral images at a fraction of the laser spot diameter. PMID:21639522

  19. Isotherms and Kinetics of Water Vapor Sorption/Desorption for Surface Films of Polyion-Surfactant Ion Complex Salts.

    PubMed

    Gustavsson, Charlotte; Piculell, Lennart

    2016-07-14

    Thin films of "complex salts" (CS = ionic surfactants with polymeric counterions) have recently been shown to respond to humidity changes in ambient air by changing their liquid crystalline structure. We here report isotherms and kinetics of water sorption/desorption for ∼10-100 μm films of alkyltrimethylammonium polyacrylate CS, measured in a dynamic gravimetric vapor sorption instrument over a 0-95% relative humidity (RH) range. The sorption per ion pair was similar to that observed for common ionomers. A kinetic model for the water exchange is presented, assuming that the "external" transport between the vapor reservoir and the film surface is rate-determining. The model predicts that the water content, after a small stepwise change of the reservoir RH, should vary exponentially with time, with a time constant proportional to both the slope of the sorption isotherm and the film thickness. These predictions were confirmed for our films over large RH ranges, and the external mass transfer coefficient in our setup was calculated from the experimental data. Expressions derived for the Biot number (ratio of characteristic times for internal and external water transport) for the considered limiting case strongly indicate that external water transport should quite generally affect, or even dominate, the measured kinetics for similarly thin hydrated films. PMID:27327628

  20. Vacuum compatible sample positioning device for matrix assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry imaging

    SciTech Connect

    Aizikov, Konstantin; Lin, Tzu-Yung; Smith, Donald F.; Heeren, Ron M. A.; Chargin, David A.; Ivanov, Sergei; O'Connor, Peter B.

    2011-05-15

    The high mass accuracy and resolving power of Fourier transform ion cyclotron resonance mass spectrometers (FT-ICR MS) make them ideal mass detectors for mass spectrometry imaging (MSI), promising to provide unmatched molecular resolution capabilities. The intrinsic low tolerance of FT-ICR MS to RF interference, however, along with typically vertical positioning of the sample, and MSI acquisition speed requirements present numerous engineering challenges in creating robotics capable of achieving the spatial resolution to match. This work discusses a two-dimensional positioning stage designed to address these issues. The stage is capable of operating in {approx}1 x 10{sup -8} mbar vacuum. The range of motion is set to 100 mm x 100 mm to accommodate large samples, while the positioning accuracy is demonstrated to be less than 0.4 micron in both directions under vertical load over the entire range. This device was integrated into three different matrix assisted laser desorption/ionization (MALDI) FT-ICR instruments and showed no detectable RF noise. The ''oversampling'' MALDI-MSI experiments, under which the sample is completely ablated at each position, followed by the target movement of the distance smaller than the laser beam, conducted on the custom-built 7T FT-ICR MS demonstrate the stability and positional accuracy of the stage robotics which delivers high spatial resolution mass spectral images at a fraction of the laser spot diameter.

  1. Hand-held portable desorption atmospheric pressure chemical ionization ion source for in situ analysis of nitroaromatic explosives.

    PubMed

    Jjunju, Fred P M; Maher, Simon; Li, Anyin; Syed, Sarfaraz U; Smith, Barry; Heeren, Ron M A; Taylor, Stephen; Cooks, R Graham

    2015-10-01

    A novel, lightweight (0.6 kg), solvent- and gas-cylinder-free, hand-held ion source based on desorption atmospheric pressure chemical ionization has been developed and deployed for the analysis of nitroaromatic explosives on surfaces in open air, offering portability for in-field analysis. A small, inexpensive, rechargeable lithium polymer battery was used to power the custom-designed circuitry within the device, which generates up to ±5 kV dc voltage to ignite a corona discharge plasma in air for up to 12 h of continuous operation, and allowing positive- and negative-ion mass spectrometry. The generated plasma is pneumatically transported to the surface to be interrogated by ambient air at a rate of 1-3.5 L/min, compressed using a small on-board diaphragm pump. The plasma source allows liquid or solid samples to be examined almost instantaneously without any sample preparation in the open environment. The advantages of low carrier gas and low power consumption (<6 W), as well as zero solvent usage, have aided in developing the field-ready, hand-held device for trigger-based, "near-real-time" sampling/ionization. Individual nitroaromatic explosives (such as 2,4,6-trinitrotoluene) can be easily detected in amounts as low as 5.8 pg with a linear dynamic range of at least 10 (10-100 pg), a relative standard deviation of ca. 7%, and an R(2) value of 0.9986. Direct detection of several nitroaromatic compounds in a complex mixture without prior sample preparation is demonstrated, and their identities are confirmed by tandem mass spectrometry fragmentation patterns. PMID:26329926

  2. Savannah River Site's Site Specific Plan

    SciTech Connect

    Not Available

    1991-08-01

    This Site Specific Plan (SSP) has been prepared by the Savannah River Site (SRS) in order to show the Environmental Restoration and Waste Management activities that were identified during the preparation of the Department of Energy-Headquarters (DOE-HQ) Environmental Restoration and Waste Management Five-Year Plan (FYP) for FY 1992--1996. The SSP has been prepared in accordance with guidance received from DOE-HQ. DOE-SR is accountable to DOE-HQ for the implementation of this plan. The purpose of the SSP is to develop a baseline for policy, budget, and schedules for the DOE Environmental Restoration and Waste Management activities. The plan explains accomplishments since the Fiscal Year (FY) 1990 plan, demonstrates how present and future activities are prioritized, identifies currently funded activities and activities that are planned to be funded in the upcoming fiscal year, and describes future activities that SRS is considering.

  3. Initial velocity distributions of ions generated by in-flight laser desorption/ionization of individual polystyrene latex microparticles as studied by the delayed ion extraction method.

    PubMed

    Vera, César Costa; Trimborn, Achim; Hinz, Klaus-Peter; Spengler, Bernhard

    2005-01-01

    The delayed ion extraction method has been used to study characteristics of the initial velocity distributions of positive and negative ions produced simultaneously by laser desorption/ionization (LDI) from non-impacted single aerosol polymeric particles, using a bipolar time-of-flight (TOF) instrument (LAMPAS 2). Due to the geometry of the setup and the characteristics of the ablation process, only the projections of the velocities on the axis of the mass spectrometer can be directly studied. Additionally, since the mean initial velocity under these conditions should be close to zero, it was necessary to extend the method by taking into account higher order contributions of the velocity distribution. Theoretical expressions for these higher order terms are presented and discussed. The bipolar characteristics of the instrument permit evaluation and treatment of a possible instrumental artifact caused by small inclinations of the ionizing laser with respect to the ideal incidence direction. Results of a number of experiments are presented and discussed in relation to the theoretical expressions presented, and to possible ablation scenarios. Evidence pointing out that, under our experimental conditions, only partial ablation of the latex particles occurs was obtained. The variance of the distribution of the projection of the initial velocities can be directly estimated from these results. By assuming that the total initial velocities of the ions are developed completely according to a single-temperature adiabatic expansion mechanism, temperatures of approximately 50 K/Da can be assigned to the ion clouds from the variance estimations. If a two-temperature model is used, a radial temperature of about 100 K/Da results. These values are in reasonable agreement with results for polymer ablation from the literature. PMID:15593241

  4. Coupling laser ablation/desorption electrospray ionization to atmospheric pressure drift tube ion mobility spectrometry for the screening of antimalarial drug quality.

    PubMed

    Harris, Glenn A; Graf, Stephan; Knochenmuss, Richard; Fernández, Facundo M

    2012-07-01

    Significant developments in the field of ambient desorption/ionization mass spectrometry (MS) have led to high-throughput direct analysis and imaging capabilities. However, advances in coupling ambient ionization techniques with standalone drift tube ion mobility spectrometry (DTIMS) have been comparatively slower, despite the attractive ruggedness and simplicity of IMS. In this study, we have developed and characterized a laser ablation/desorption electrospray ionization (LADESI) DTIMS platform, and applied it to the detection of active pharmaceutical ingredients (APIs) in antimalarial tablets collected in developing countries. The overarching goal of this work was to perform an initial evaluation of LADESI DTIMS as a technique with the potential for constituting the core of a portable drug quality-testing platform. The set-up consisted of an IR laser for desorption and an electrospray ionizer for capturing the ablated plume coupled to a high-resolution monolithic resistive glass drift tube ion mobility spectrometer. For more confident API identification, tablet extracts were also investigated via electrospray IM MS to correlate LADESI DTIMS reduced mobility (K(0)) values to m/z values. Overall, it was found that the IR LADESI DTIMS platform provided distinct ion mobility spectral fingerprints that could be used to detect the presence of the expected APIs, helping to distinguish counterfeit drugs from their genuine counterparts. PMID:22606690

  5. A high-resolution scanning microprobe matrix-assisted laser desorption/ionization ion source for imaging analysis on an ion trap/Fourier transform ion cyclotron resonance mass spectrometer.

    PubMed

    Koestler, Martin; Kirsch, Dieter; Hester, Alfons; Leisner, Arne; Guenther, Sabine; Spengler, Bernhard

    2008-10-01

    A new scanning microprobe matrix-assisted laser desorption/ionization (SMALDI) ion source for high spatial resolution has been developed for linear ion trap and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). The source is fully compatible with commercial ion trap flanges (such as the LTQ series, Thermo Fisher Scientific). The source is designed for atmospheric pressure (AP) operation but is also suitable for mid-pressure operation. The AP mode is especially useful for investigating volatile compounds. The source can be interchanged with other ion sources within a minute when operated in the AP mode. Combining high-lateral resolution MALDI imaging with high mass resolution and high mass accuracy mass spectrometry, available in the FT-ICR mode, provides a new quality of analytical information, e.g. from biological samples. First results obtained with the new ion source demonstrate a maximum lateral resolution of 0.6 by 0.5 microm. Depending on the limit of detection of the chosen mass analyzer, however, the size of the focus had to be enlarged to a diameter of up to 8 microm in the FT-ICR mode, in order to create enough ions for detection. Mass spectra acquired for analytical imaging were obtained from single laser pulses per pixel in all the experiments. This mode allows us to investigate biological thin sections with desorption focus diameters in the micrometer range, known to cause complete evaporation of material under the laser focus with a very limited number of laser pulses. As a first example, peptide samples deposited in microstructures were investigated with the new setup. A high quality and validity of the acquired images were obtained in the ion trap mode due to the low limit of detection. High mass resolution and accuracy but poorer image quality were obtained in the ICR mode due to the lower detection sensitivity of the ICR detector. PMID:18819119

  6. The Connectivity Between Site-Specific Life Cycle Impact Assessment and Site-Specific Weighting

    EPA Science Inventory

    The goal of many LCIAs is to come to a single score with all of the impacts from a wide variety of impact assessments weighted to form this single score. My past experiences with developing site-specific impact assessment methodologies and how this can change the valuation porti...

  7. Site-specific seismic hazard analyses

    NASA Astrophysics Data System (ADS)

    Montalva, Gonzalo Andres

    Current seismic hazard analyses are generally performed using probabilistic methods. When dealing with a specific site, the typical methodology involves using a ground motion prediction equation (GMPE) to estimate the rock outcrop ground motion and associated variability, then the ground motion is propagated to the ground surface by site response analysis. The site response process is inherently variable. Including this uncertainty in site response analyses without modifying the input ground motion uncertainty produces double counting of the uncertainty associated with site response. In this dissertation the total uncertainty is partitioned into its several contributing components, quantifying these components, and proposing methods to perform site-specific seismic hazard analyses without double counting uncertainties. Four random field models were developed, and an existing one was fitted to a different database. These models can be used to generate shear-wave velocity profiles for site response analyses. Two types of models are presented, using Gaussian random fields, and using Markov Chains. The first ones showed better performance, and among those a stationary Gaussian model (stationary on rho) showed the best performance, and it is the simplest among the five models. Three GMPE's were developed, one only from surface records, one from "at-depth" records, and a third one combining surface and "at-depth" records. The results show the iv same magnitude and distance scaling for the three equations. For stations that recorded a large number of records, total uncertainty was measured by the standard deviation of the observed minus predicted, and similarly for intra-event residuals. These statistics serve as lower bounds for site-specific seismic hazard analyses, note that these standard deviations are non-ergodic. The use of a GMPE capable of predicting bedrock and surface median ground motions, allows the partition of the components of the total uncertainty at the

  8. A mass spectrometric system for analyzing thermal desorption spectra of ion-implanted argon and cesium in tungsten. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Wood, G. M., Jr.

    1974-01-01

    A mass spectrometric system for determining the characteristics of materials used in instrumental development and aerospace applications was developed. The desorption spectra of cesium that was ion-implanted into polycrystalline tungsten and the effects on the spectra of bombardment of the tungsten by low energy (70 eV) electrons were investigated. Work function changes were measured by the retarding potential diode method. Flash desorption characteristics were observed and gas-reaction mechanisms of the surface of heated metal filaments were studied. Desorption spectra were measured by linearly increasing the sample temperature at a selected rate, the temperature cycling being generated from a ramp-driven dc power supply, with the mass spectrometer tuned to a mass number of interest. Results of the study indicate an anomolous desorption mechanism following an electron bombardment of the sample surface. The enhanced spectra are a function of the post-bombardment time and energy and are suggestive of an increased concentration of cesium atoms, up to 10 or more angstroms below the surface.

  9. Ultrasensitive characterization of site-specific glycosylation of affinity-purified haptoglobin from lung cancer patient plasma using 10 μm i.d. porous layer open tubular liquid chromatography-linear ion trap collision-induced dissociation/electron transfer dissociation mass spectrometry.

    PubMed

    Wang, Dongdong; Hincapie, Marina; Rejtar, Tomas; Karger, Barry L

    2011-03-15

    Site-specific analysis of protein glycosylation is important for biochemical and clinical research efforts. Glycopeptide analysis using liquid chromatography-collision-induced dissociation/electron transfer dissociation mass spectrometry (LC-CID/ETD-MS) allows simultaneous characterization of the glycan structure and attached peptide site. However, due to the low ionization efficiency of glycopeptides during electrospray ionization, 200-500 fmol of sample per injection is needed for a single LC-MS run, which makes it challenging for the analysis of limited amounts of glycoprotein purified from biological matrixes. To improve the sensitivity of LC-MS analysis for glycopeptides, an ultranarrow porous layer open tubular (PLOT) LC column (2.5 m × 10 μm i.d.) was coupled to a linear ion trap (LTQ) collision-induced dissociation/electron transfer dissociation mass spectrometer to provide sensitive analysis of N-linked protein glycosylation heterogeneity. The potential of the developed method is demonstrated by the characterization of site-specific glycosylation using haptoglobin (Hpt) as a model protein. To limit the amount of haptoglobin to low picomole amounts of protein, we affinity purified it from 1 μL of pooled lung cancer patient plasma. A total of 26 glycoforms/glycan compositions on three Hpt tryptic glycopeptides were identified and quantified from 10 LC-MS runs with a consumption of 100 fmol of Hpt digest (13 ng of protein, 10 fmol per injection). Included in this analysis was the determination of the glycan occupancy level. At this sample consumption level, the high sensitivity of the PLOT LC-LTQ-CID/ETD-MS system allowed glycopeptide identification and structure determination, along with relative quantitation of glycans presented on the same peptide backbone, even for low abundant glycopeptides at the ∼100 amol level. The PLOT LC-MS system is shown to have sufficient sensitivity to allow characterization of site-specific protein glycosylation from trace

  10. RESRAD. Site-Specific Residual Radioactivity

    SciTech Connect

    Yu, C.

    1989-06-01

    RESRAD is designed to derive site-specific guidelines for allowable residual concentrations of radionuclides in soil. A guideline is defined as a radionuclide concentration or a level of radiation or radioactivity that is acceptable if a site is to be used without radiological restrictions. Guidelines are expressed as (1) concentrations of residual radionuclides in soil, (2) concentrations of airborne radon decay products, (3) levels of external gamma radiation, (4) levels of radioactivity from surface contamination, and (5) concentrations of residual radionuclides in air and water. Soil is defined as unconsolidated earth material, including rubble and debris that may be present. The controlling principles of all guidelines are (1) the annual radiation dose received by a member of the critical population group from the residual radioactive material - predicted by a realistic but reasonably conservative analysis and averaged over a 50 year period - should not exceed 100 mrem/yr, and (2) doses should be kept as low as reasonably achievable. All significant exposure pathways for the critical population group are considered in deriving soil guidelines. These pathways include direct exposure to external radiation from the contaminated soil material; internal radiation from inhalation of airborne radionuclides; and internal radiation from ingestion of plant foods grown in the contaminated soil, meat and milk from livestock fed with contaminated fodder and water, drinking water from a contaminated well, and fish from a contaminated pond.

  11. Characterization of pyrogenic black carbon by desorption atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Podgorski, David C; Hamdan, Rasha; McKenna, Amy M; Nyadong, Leonard; Rodgers, Ryan P; Marshall, Alan G; Cooper, William T

    2012-02-01

    We present a new method for molecular characterization of intact biochar directly, without sample preparation or pretreatment, on the basis of desorption atmospheric pressure photoionization (DAPPI) coupled to Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Conventional ionization methods (e.g., electrospray or atmospheric pressure photoionization) for characterization of natural organic matter have limited utility for the characterization of chars due to incomplete solubility in common solvents. Therefore, direct ionization techniques that do not require sample dissolution prior to analysis are ideal. Here, we apply DAPPI FTICR mass spectrometry to enable the first molecular characterization of uncharred parent oak biomass and after combustion (250 °C) or pyrolysis (400 °C). Parent oak is primarily composed of cellulose-, lignin-, and resin-like compounds. Oak combusted at 250 °C contains condensed aromatic compounds with low H/C and O/C ratios while retaining compounds with high H/C and O/C ratios. The bimodal distribution of aromatic and aliphatic compounds observed in the combusted oak sample is attributed to incomplete thermal degradation of lignin and hemicellulose. Pyrolyzed oak constituents exhibit lower H/C and O/C ratios: approximately three-quarters of the identified species are aromatic. DAPPI FTICR MS results agree with bulk elemental composition as well as functional group distributions determined by elemental analysis and solid state (13)C NMR spectroscopy. Complete molecular characterization of biomass upon thermal transformation may provide insight into the biogeochemical cycles of biochar and future renewable energy sources, particularly for samples currently limited by solubility, separation, and sample preparation. PMID:22242739

  12. Experimental investigations of the internal energy of molecules evaporated via laser-induced acoustic desorption into a Fourier transform ion cyclotron resonance mass spectrometer.

    PubMed

    Shea, Ryan C; Petzold, Christopher J; Liu, Ji-Ang; Kenttämaa, Hilkka I

    2007-03-01

    The internal energy of neutral gas-phase organic and biomolecules, evaporated by means of laser-induced acoustic desorption (LIAD) into a Fourier transform ion cyclotron resonance mass spectrometer, was investigated through several experimental approaches. The desorbed molecules were demonstrated not to undergo degradation during the desorption process by collecting LIAD-evaporated molecules and subjecting them to analysis by electrospray ionization/quadrupole ion trap mass spectrometry. Previously established gas-phase basicity values were remeasured for LIAD-evaporated organic molecules and biomolecules with the use of the bracketing method. No endothermic reactions were observed. The remeasured basicity values are in close agreement with the values reported in the literature. The amount of internal energy deposited during LIAD is concluded to be less than a few kilocalories per mole. Chemical ionization with a series of proton-transfer reagents was employed to obtain a breakdown curve for a protonated dipeptide, Val-Pro, evaporated by LIAD. Comparison of this breakdown curve with a previously published analogous curve obtained by using substrate-assisted laser desorption (SALD) to evaporate the peptide suggests that the molecules evaporated via LIAD have a similar internal energy as those evaporated via SALD. PMID:17263513

  13. Site-Specific, Climate-Friendly Farming

    NASA Astrophysics Data System (ADS)

    Brown, D. J.; Brooks, E. S.; Eitel, J.; Huggins, D. R.; Painter, K.; Rupp, R.; Smith, J. L.; Stockle, C.; Vierling, L. A.

    2011-12-01

    Of the four most important atmospheric greenhouse gasses (GHG) enriched through human activities, only nitrous oxide (N2O) emissions are due primarily to agriculture. However, reductions in the application of synthetic N fertilizers could have significant negative consequences for a growing world population given the crucial role that these fertilizers have played in cereal yield increases since WWII. Increasing N use efficiency (NUE) through precision management of agricultural N in space and time will therefore play a central role in the reduction of agricultural N2O emissions. Precision N management requires a greater understanding of the spatio-temporal variability of factors supporting N management decisions such as crop yield, water and N availability, utilization and losses. We present an overview of a large, collaborative, multi-disciplinary project designed to improve our basic understanding of nitrogen (N), carbon (C) and water (H2O) spatio-temporal dynamics for wheat-based cropping systems on complex landscapes, and develop management tools to optimize water- and nitrogen-use efficiency for these systems and landscapes. Major components of this project include: (a) cropping systems experiments addressing nitrogen application rate and seeding density for different landscape positions; (b) GHG flux experiments and monitoring; (c) soil microbial genetics and stable isotope analyses to elucidate biochemical pathways for N2O production; (d) proximal soil sensing for construction of detailed soil maps; (e) LiDAR and optical remote sensing for crop growth monitoring; (f) hydrologic experiments, monitoring, and modeling; (g) refining the CropSyst simulation model to estimate biophysical processes and GHG emissions under a variety of management and climatic scenarios; and (h) linking farm-scale enterprise budgets to simulation modeling in order to provide growers with economically viable site-specific climate-friendly farming guidance.

  14. Evaluation of combined matrix-assisted laser desorption/ionization time-of-flight and matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry experiments for peptide mass fingerprinting analysis.

    PubMed

    da Silva, David; Wasselin, Thierry; Carré, Vincent; Chaimbault, Patrick; Bezdetnaya, Lina; Maunit, Benoît; Muller, Jean-François

    2011-07-15

    Peptide Mass Fingerprinting (PMF) is still of significant interest in proteomics because it allows a large number of complex samples to be rapidly screened and characterized. The main part of post-translational modifications is generally preserved. In some specific cases, PMF suffers from ambiguous or unsuccessful identification. In order to improve its reliability, a combined approach using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICRMS) was evaluated. The study was carried out on bovine serum albumin (BSA) digest. The influence of several important parameters (the matrix, the sample preparation method, the amount of the analyte) on the MOWSE score and the protein sequence coverage were evaluated to allow the identification of specific effects. A careful investigation of the sequence coverage obtained by each kind of experiment ensured the detection of specific peptides for each experimental condition. Results highlighted that DHB-FTICRMS and DHB- or CHCA-TOFMS are the most suited combinations of experimental conditions to achieve PMF analysis. The association (convolution) of the data obtained by each of these techniques ensured a significant increase in the MOWSE score and the protein sequence coverage. PMID:21638364

  15. Matrix-assisted laser desorption/ionization mass spectrometric imaging of complete rat sections using a triple quadrupole linear ion trap.

    PubMed

    Hopfgartner, Gérard; Varesio, Emmanuel; Stoeckli, Markus

    2009-03-01

    The fast imaging of complete rat sections by matrix-assisted laser desorption/ionization on a triple quadrupole linear ion trap is demonstrated. After administration of the pharmaceutical compound (MW=467.4 u) at 0.5 mg/kg the parent drug could be identified in full scan mode and in the enhanced product ion spectrum mode. Furthermore, the precursor ion mode could also be used to monitor the presence of the parent drug in the tissue section. In the selected reaction monitoring mode, using a laser frequency of 1000 Hz and a rastering speed of about 18 mm/s, a targeted representative image of drug distribution in a rat section could be obtained in less than 15 min. PMID:19206086

  16. Comparative study of electron stimulated positive-ion desorption from LiCl and 1-ethyl-3-methylimidazolium bis[trifluoromethylsulfonyl]imide

    NASA Astrophysics Data System (ADS)

    Souda, Ryutaro

    2009-08-01

    The mechanism of electron stimulated desorption (ESD) from LiCl has been investigated in comparison with that from a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium bis[trifluoromethylsulfonyl]imide, [emim][Tf2N]. The bonding natures of these materials are discussed based on the matrix effect in positive-ion yields. The [emim]+ and fragment ions are emitted from the [emim][Tf2N] molecule unless it is in direct contact with a metal surface, suggesting that the ions are emitted provided that the electronic excitation can be localized in each molecule. In contrast, the electronic excitation tends to be delocalized over the LiCl film, as evidenced by a monotonic increase of a Li+ yield in the multilayer regime. The Li+ ion is created via gas-phase ionization of desorbed neutrals or emitted directly from the surface, in which self-trapped excitons or hot carriers created in the bulk play a role. The Li+ and Li+(LiCl) ions are emitted efficiently from LiCl nanoclusters formed on a rare-gas solid film via Coulombic fission. The delocalized nature of hot holes is also manifested by steep decay of the ion yields with increasing LiCl coverage. The structural transformation of [emim][Tf2N] during the phase transition is also revealed based on ESD positive-ion yields as a function of temperature.

  17. Comparative study of electron stimulated positive-ion desorption from LiCl and 1-ethyl-3-methylimidazolium bis[trifluoromethylsulfonyl]imide.

    PubMed

    Souda, Ryutaro

    2009-08-28

    The mechanism of electron stimulated desorption (ESD) from LiCl has been investigated in comparison with that from a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium bis[trifluoromethylsulfonyl]imide, [emim][Tf(2)N]. The bonding natures of these materials are discussed based on the matrix effect in positive-ion yields. The [emim](+) and fragment ions are emitted from the [emim][Tf(2)N] molecule unless it is in direct contact with a metal surface, suggesting that the ions are emitted provided that the electronic excitation can be localized in each molecule. In contrast, the electronic excitation tends to be delocalized over the LiCl film, as evidenced by a monotonic increase of a Li(+) yield in the multilayer regime. The Li(+) ion is created via gas-phase ionization of desorbed neutrals or emitted directly from the surface, in which self-trapped excitons or hot carriers created in the bulk play a role. The Li(+) and Li(+)(LiCl) ions are emitted efficiently from LiCl nanoclusters formed on a rare-gas solid film via Coulombic fission. The delocalized nature of hot holes is also manifested by steep decay of the ion yields with increasing LiCl coverage. The structural transformation of [emim][Tf(2)N] during the phase transition is also revealed based on ESD positive-ion yields as a function of temperature. PMID:19725616

  18. Design and Characterization of a High-power Laser-induced Acoustic Desorption (LIAD) Probe Coupled with a Fourier-transform Ion Cyclotron Resonance Mass Spectrometer

    PubMed Central

    Shea, Ryan C.; Habicht, Steven C.; Vaughn, Weldon E.; Kenttämaa, Hilkka I.

    2008-01-01

    We report here the construction and characterization of a high-power laser-induced acoustic desorption (LIAD) probe designed for Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometers to facilitate analysis of non-volatile, thermally labile compounds. This “next generation” LIAD probe offers significant improvements in sensitivity and desorption efficiency for analytes with larger molecular weights via the use of higher laser irradiances. Unlike the previous probes which utilized a power limiting optical fiber to transmit the laser pulses through the probe, this probe employs a set of mirrors and a focusing lens. At the end of the probe, the energy from the laser pulses propagates through a thin metal foil as an acoustic wave, resulting in desorption of neutral molecules from the opposite side of the foil. Following desorption, the molecules can be ionized by electron impact or chemical ionization. Almost an order of magnitude greater power density (up to 5.0 × 109 W/cm2) is achievable on the backside of the foil with the high-power LIAD probe compared to the earlier LIAD probes (maximum power density ~9.0 × 108 W/cm2). The use of higher laser irradiances is demonstrated not to cause fragmentation of the analyte. The use of higher laser irradiances increases sensitivity since it results in the evaporation of a greater number of molecules per laser pulse. Measurement of the average velocities of LIAD evaporated molecules demonstrates that higher laser irradiances do not correlate with higher velocities of the gaseous analyte molecules. PMID:17319645

  19. New design for a time-of-flight mass spectrometer with a liquid beam laser desorption ion source for the analysis of biomolecules

    NASA Astrophysics Data System (ADS)

    Charvat, A.; Lugovoj, E.; Faubel, M.; Abel, B.

    2004-05-01

    We describe a novel liquid beam mass spectrometer, based on a recently discovered nanosecond laser desorption phenomenon, [W. Kleinekofort, J. Avdiev, and B. Brutschy, Int. J. Mass Ion. Processes 152, 135 (1996)] which allows the liquid-to-vacuum transfer, and subsequent mass analysis of pre-existing ions and ionic associates from liquid microjets of aqueous solutions. The goal of our novel technical approach is to establish a system with good mass resolution that implements improvements on critical components that make the system more reliable and easier to operate. For laser desorption pulsed dye-laser difference frequency mixing is used that provides tunable infrared light near the absorption maximum of liquid water around 3 μm. Different types of liquid beam glass nozzles (convergent capillary and aperture plate nozzles) are investigated and characterized. Starting from theoretical considerations of hydrodynamic drag forces on micrometer size droplets in supersonic rarefied gas flows we succeeded in capturing efficiently the liquid beam in a liquid beam recycling trap operating at the vapor pressure of liquid water. For improving the pollution resistance, the liquid jet high vacuum ion source region is spatially separated from the reflectron time-of-flight mass spectrometer (TOF-MS) working behind a gate valve in an ultrahigh vacuum environment. A simple (simulation optimized) ion optics is employed for the ion transfer from the source to the high vacuum region. This new feature is also mostly responsible for the improved mass resolution. With the present tandem-TOF-MS setup a resolution of m/Δm≈1800 for the low and m/Δm≈700 in the high mass region has been obtained for several biomolecules of different mass and complexity (amino acids, insulin, and cytochrome c).

  20. Exploring Biosignatures Associated with Thenardite by Geomatrix-Assisted Laser Desorption/Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (GALDI-FTICR-MS)

    SciTech Connect

    C. Doc Richardson; Nancy W. Hinman; Timothy R. McJunkin; J. Michelle Kotler; Jill R. Scott

    2008-10-01

    Geomatrix-assisted laser desorption/ionization (GALDI) in conjunction with a Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS) has been employed to determine how effectively bio/organic molecules associated with the mineral thenardite (Na2SO4) can be detected. GALDI is based on the ability of the mineral host to assist desorption and ionization of bio/organic molecules without additional sample preparation. When glycine was mixed with thenardite, glycine was deprotonated to produce C2H4NO-2 at m/z 74.025. The combination of stearic acid with thenardite produced a complex cluster ion at m/z 390.258 in the negative mode, which was assigned a composition ofC18H39O7Na-. Anatural sample of thenardite from Searles Lake in California also produced a peak at m/z 390.260. The bio/organic signatures in both the laboratory-based and natural samples were heterogeneously dispersed as revealed by chemical imaging. The detection limits for the stearic acid and thenardite combination were estimated to be 3 parts per trillion or~7 zeptomoles (10-21) per laser spot. Attempts to improve the signal-to-noise ratio by co-adding FTICR-MS data predetermined to contain the biosignatures of interest revealed problems due to a lack of phase coherence between data sets.

  1. Direct analysis of pharmaceutical drug formulations using ion mobility spectrometry/quadrupole-time-of-flight mass spectrometry combined with desorption electrospray ionization.

    PubMed

    Weston, Daniel J; Bateman, Robert; Wilson, Ian D; Wood, Tim R; Creaser, Colin S

    2005-12-01

    A novel approach to the rapid analysis of pharmaceutical drug formulations using hyphenated ion mobility spectrometry (IMS) and time-of-flight mass spectrometry (ToF-MS) that requires no sample pretreatment or chromatographic separation is described. A modified quadrupole time-of-flight mass spectrometer containing an ion mobility drift cell was used for gas-phase electrophoretic separation of ions prior to ToF-MS detection. The generation of sample ions directly from tablets and cream formulations was effected by desorption electrospray ionization (DESI) using a modified electrospray ion source. The analysis of a range of over-the-counter and prescription tablet formulations is described, including histamine H2 receptor antagonist (ranitidine), analgesic (paracetamol), opiate (codeine), and aromatase inhibitor anticancer (anastrozole) drugs. The successful determination of active drugs from soft formulations, such as an antiseptic cream (chlorhexidine) and a nicotine-containing skin patch, is also presented. Limits of detection for the active drugs using the DESI/IMS/ToF-MS method fell within the high-picomole to nanomole range. In all cases, the use of ion mobility drift tube separation showed increased selectivity for active drug responses (present as low as 0.14% w/w) over excipient responses such as poly(ethylene glycol). Tandem mass spectrometric analysis of precursor ions separated by IMS allowed positive confirmation of active drugs with little loss of ion mobility efficiency. The ability to analyze hard or soft pharmaceutical formulations directly by DESI combined with ion mobility spectrometry/mass spectrometry in approximately 2 min demonstrates the potential applicability of this novel method to pharmaceutical screening of low-molecular-weight drug formulations with high selectivity over the formulation vehicle. PMID:16316164

  2. Removal of Co(II), Cu(II) and Pb(II) ions by polymer based 2-hydroxyethyl methacrylate: thermodynamics and desorption studies

    PubMed Central

    2012-01-01

    Removal thermodynamics and desorption studies of some heavy metal ions such as Co(II), Cu(II) and Pb(II) by polymeric surfaces such as poly 2-hydroxyethyl methacrylate (PHEMA) and copolymer 2-hydroxyethyl methacrylate with monomer methyl methacrylate P(MMA-HEMA) as adsorbent surfaces from aqueous single solution were investigated with respect to the changes in pH of solution, adsorbent composition, contact time and temperature in the individual aqueous solution. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained and the results revealed that the Langmuir isotherm fitted the experiment results better than Freundlich isotherm. Using the Langmuir model equation, the monolayer removal capacity of PHEMA surface was found to be 0.7388, 0.8396 and 3.0367 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions and removal capacity of P(MMA-HEMA) was found to be 28.8442, 31.1526 and 31.4465 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions, respectively. Changes in the standard Gibbs free energy (ΔG0), standard enthalpy (ΔH0) and standard entropy (ΔS0) showed that the removals of mentioned ions onto PHEMA and P(MMA-HEMA) are spontaneous and exothermic at 293–323 K. The maximum desorption efficiency was 75.26% for Pb(II) using 0.100 M HNO3, 70.10% for Cu(II) using 0.100 M HCl, 59.20% for 0.100 M HCl 63.67% Co(II). PMID:23369255

  3. Site Specific Management of Cotton Production in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific management or precision agriculture, as it is evolving in large-scale crop production, offers promising new methods for managing cotton production for optimized yields, maximized profitability, and minimized environmental pollution. However, adaptation of site-specific theory and meth...

  4. Site-specific crop management using geophysical proximal sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Key components of site-specific crop management are (i) identifying the site-specific factors that influence within-field crop yield variation and (ii) spatially characterizing those factors. Geo-referenced measurements of apparent soil electrical conductivity (ECa) provide a potential means of cha...

  5. Double clicking for site-specific coupling of multiple enzymes.

    PubMed

    Lim, Sung In; Cho, Jinhwan; Kwon, Inchan

    2015-09-14

    A method to site-specifically couple multiple enzymes is reported. The approach is based on the site-specific incorporation of a clickable non-natural amino acid into enzymes and two compatible click reactions. The multi-enzyme reaction system exhibited enhanced catalytic efficiency over the respective free enzymes. PMID:26191550

  6. Site-Specific Weed Management: Myth or Magic?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific weed management (SSWM) is a potential method to reduce the risks of herbicide use on water quality and public health without impacting crop yield. With site-specific weed management, areas of the field are left untreated where control is not economically justified. Where control is nee...

  7. SITE-SPECIFIC CHARACTERIZATION OF SOIL RADON POTENTIALS

    EPA Science Inventory

    The report presents a theoretical basis for measuring site-specific radon potentials. However, the empirical measurements suggest that the precision of such measurements is marginal, leaving an uncertainty of about a factor of 2 in site-specific estimates. Although this may be us...

  8. Enhancing adoption of site-specific variable rate sprinkler systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than twenty years of private and public research on site-specific variable-rate sprinkler irrigation (SS-VRI) has resulted in very limited commercial adoption of the technology. Documented and proven water conservation strategies using site-specific irrigation are quite limited, and its cost-ef...

  9. 77 FR 22772 - Environmental Management Site-Specific Advisory Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-17

    ... Environmental Management Site-Specific Advisory Board AGENCY: Office of Environmental Management, Department of... Administration, notice is hereby given that the Environmental Management Site-Specific Advisory Board (EM SSAB... recommendations to the Assistant Secretary for Environmental Management (EM) concerning issues affecting the......

  10. Charge-state dependence of fast heavy-ion-induced desorption yields described in a thermal model

    SciTech Connect

    Nieschler, E.; Nees, B.; Voit, H.

    1988-11-01

    Yields for secondary ions desorbed from valine, tetrabutylammonium tetraphenylborate, and CsI samples by 13- and 30-MeV /sup 16/O ions have been measured as a function of the primary-ion charge state. The experimental data can be reproduced in terms of a simple thermal model.

  11. Ion Yields in the Coupled Chemical and Physical Dynamics Model of Matrix-Assisted Laser Desorption/Ionization

    NASA Astrophysics Data System (ADS)

    Knochenmuss, Richard

    2015-08-01

    The Coupled Chemical and Physical Dynamics (CPCD) model of matrix assisted laser desorption ionization has been restricted to relative rather than absolute yield comparisons because the rate constant for one step in the model was not accurately known. Recent measurements are used to constrain this constant, leading to good agreement with experimental yield versus fluence data for 2,5-dihydroxybenzoic acid. Parameters for alpha-cyano-4-hydroxycinnamic acid are also estimated, including contributions from a possible triplet state. The results are compared with the polar fluid model, the CPCD is found to give better agreement with the data.

  12. Momentum resolved electron stimulated desorption ion angular distribution, a new technique, probing the low frequency motion of adsorbed molecules on single crystal surfaces

    SciTech Connect

    Ahner, J.; Mocuta, D.; Yates, J.T. Jr.

    1999-07-01

    A new technique, momentum resolved electron stimulated desorption ion angular distribution (ESDIAD), provides a method for taking snapshots of the zero-point position and lateral momentum of particles adsorbed on crystalline surfaces. By employing state-of-the-art electronics and computer technology it is possible to record for each desorbing particle the desorption direction together with the flight time. High momentum and directional resolved images are obtained, with time-of-flight resolution in the picosecond range and data acquisition rates up to 100 kHz. This enables us to deconvolute spatial and momentum contributions to the ESDIAD pattern and to map the low frequency motion of the adsorbed particles. These maps reflect the adsorbate interactions with the substrate and with neighboring species on the substrate. For selected examples it is demonstrated that by measuring the three dimensional momentum vector for each desorbing particle it is possible to probe the lowest energy states of adsorbed species, as well as to measure the momentum distribution when the adsorbed species gains thermal energy. Such information can be used as a basis for thinking about anisotropies in lateral motion of particles on surfaces. One major opportunity involves the study of dissimilar chemisorbed species which, when imaged together in momentum and real space, give new insights into the first stages of interaction between the species, leading ultimately to a chemical reaction. {copyright} {ital 1999 American Vacuum Society.}

  13. Comparing Laser Desorption Ionization and Atmospheric Pressure Photoionization Coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry To Characterize Shale Oils at the Molecular Level

    USGS Publications Warehouse

    Cho, Yunjo; Jin, Jang Mi; Witt, Matthias; Birdwell, Justin E.; Na, Jeong-Geol; Roh, Nam-Sun; Kim, Sunghwan

    2013-01-01

    Laser desorption ionization (LDI) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to analyze shale oils. Previous work showed that LDI is a sensitive ionization technique for assessing aromatic nitrogen compounds, and oils generated from Green River Formation oil shales are well-documented as being rich in nitrogen. The data presented here demonstrate that LDI is effective in ionizing high-double-bond-equivalent (DBE) compounds and, therefore, is a suitable method for characterizing compounds with condensed structures. Additionally, LDI generates radical cations and protonated ions concurrently, the distribution of which depends upon the molecular structures and elemental compositions, and the basicity of compounds is closely related to the generation of protonated ions. This study demonstrates that LDI FT-ICR MS is an effective ionization technique for use in the study of shale oils at the molecular level. To the best of our knowledge, this is the first time that LDI FT-ICR MS has been applied to shale oils.

  14. Laser-desorption mass spectrometry/mass spectrometry and the mechanism of desorption ionization

    SciTech Connect

    Zakett, D.; Schoen, A.E.; Cooks, R.G.; Hemberger, P.H.

    1981-03-11

    This paper reports sucrose mass spectra obtained by combining laser desorption with mass spectrometry/mass spectrometry. Remarkable similarities in fragmentation behavior with secondary ion mass spectra (SIMS) provide evidence for mechanistic similarities between SIMS and laser desorption (LD). Attachment of alkali metals to organic molecules (cationization) is a common feature of desorption ionization. This process also occurs during laser desorption of involatile compounds which further indicates the existence of underlying similarities between LD and SIMS. Steady ion currents (several thousand ions per laser pulse) of cationized sucrose are obtained for relatively long periods (minutes).

  15. Analysis of neutral oligosaccharides for structural characterization by matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry.

    PubMed

    Ojima, Noriyuki; Masuda, Katsuyoshi; Tanaka, Koichi; Nishimura, Osamu

    2005-03-01

    We have acquired multi-stage mass spectra (MSn) of four branched N-glycans derived from human serum IgG by matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF-MS) in order to demonstrate high sensitivity structural analysis. [M+H]+ and [M+Na]+ ions were detected in the positive mode. The detection limit of [M+Na]+ in MS/MS and MS3 measurements for structural analysis was found to be 100 fmol, better than that for [M+H]+. The [M+H]+ ions subsequently fragmented to produce predominantly a Y series of fragments, whereas [M+Na]+ ions fragmented to give a complex mixture of B and Y ions together with some cross-ring fragments. Three features of MALDI-QIT-CID fragmentation of [M+Na]+ were cleared by the analysis of MS/MS, MS3 and MS4 spectra: (1) the fragment ions resulting from the breaking of a bond are more easily generated than that from multi-bond dissociation; (2) the trimannosyl-chitobiose core is either hardly dissociated, easily ionized or it is easy to break a bond between N-acetylglucosamine and mannose; (3) the fragmentation by loss of only galactose from the non-reducing terminus is not observed. We could determine the existence ratios of candidates for each fragment ion in the MS/MS spectrum of [M+Na]+ by considering these features. These results indicate that MSn analysis of [M+Na]+ ions is more useful for the analysis of complicated oligosaccharide structures than MS/MS analysis of [M+H]+, owing to the higher sensitivity and enhanced structural information. Furthermore, two kinds of glycans, with differing branch structures, could be distinguished by comparing the relative fragment ion abundances in the MS3 spectrum of [M+Na]+. These analyses demonstrate that the MSn technology incorporated in MALDI-QIT-TOF-MS can facilitate the elucidation of structure of complex branched oligosaccharides. PMID:15712371

  16. Electronic Desorption of gas from metals

    SciTech Connect

    Molvik, A W; Kollmus, H; Mahner, E; Covo, M K; Bender, M; Bieniosek, F M; Kramer, A; Kwan, J; Prost, L; Seidl, P A; Westenskow, G

    2006-11-02

    During heavy ion operation in several particle accelerators world-wide, dynamic pressure rises of orders of magnitude were triggered by lost beam ions that bombarded the vacuum chamber walls. This ion-induced molecular desorption, observed at CERN, GSI, and BNL, can seriously limit the ion beam lifetime and intensity of the accelerator. From dedicated test stand experiments we have discovered that heavy-ion induced gas desorption scales with the electronic energy loss (dE{sub e}/dx) of the ions slowing down in matter; but it varies only little with the ion impact angle, unlike electronic sputtering.

  17. Site-specific recombinases as tools for heterologous gene integration.

    PubMed

    Hirano, Nobutaka; Muroi, Tetsurou; Takahashi, Hideo; Haruki, Mitsuru

    2011-10-01

    Site-specific recombinases are the enzymes that catalyze site-specific recombination between two specific DNA sequences to mediate DNA integration, excision, resolution, or inversion and that play a pivotal role in the life cycles of many microorganisms including bacteria and bacteriophages. These enzymes are classified as tyrosine-type or serine-type recombinases based on whether a tyrosine or serine residue mediates catalysis. All known tyrosine-type recombinases catalyze the formation of a Holliday junction intermediate, whereas the catalytic mechanism of all known serine-type recombinases includes the 180° rotation and rejoining of cleaved substrate DNAs. Both recombinase families are further subdivided into two families; the tyrosine-type recombinases are subdivided by the recombination directionality, and the serine-type recombinases are subdivided by the protein size. Over more than two decades, many different site-specific recombinases have been applied to in vivo genome engineering, and some of them have been used successfully to mediate integration, deletion, or inversion in a wide variety of heterologous genomes, including those from bacteria to higher eukaryotes. Here, we review the recombination mechanisms of the best characterized recombinases in each site-specific recombinase family and recent advances in the application of these recombinases to genomic manipulation, especially manipulations involving site-specific gene integration into heterologous genomes. PMID:21822899

  18. Dithranol as a Matrix for Matrix Assisted Laser Desorption/Ionization Imaging on a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

    PubMed Central

    Le, Cuong H.; Han, Jun; Borchers, Christoph H.

    2013-01-01

    Mass spectrometry imaging (MSI) determines the spatial localization and distribution patterns of compounds on the surface of a tissue section, mainly using MALDI (matrix assisted laser desorption/ionization)-based analytical techniques. New matrices for small-molecule MSI, which can improve the analysis of low-molecular weight (MW) compounds, are needed. These matrices should provide increased analyte signals while decreasing MALDI background signals. In addition, the use of ultrahigh-resolution instruments, such as Fourier transform ion cyclotron resonance (FTICR) mass spectrometers, has the ability to resolve analyte signals from matrix signals, and this can partially overcome many problems associated with the background originating from the MALDI matrix. The reduction in the intensities of the metastable matrix clusters by FTICR MS can also help to overcome some of the interferences associated with matrix peaks on other instruments. High-resolution instruments such as the FTICR mass spectrometers are advantageous as they can produce distribution patterns of many compounds simultaneously while still providing confidence in chemical identifications. Dithranol (DT; 1,8-dihydroxy-9,10-dihydroanthracen-9-one) has previously been reported as a MALDI matrix for tissue imaging. In this work, a protocol for the use of DT for MALDI imaging of endogenous lipids from the surfaces of mammalian tissue sections, by positive-ion MALDI-MS, on an ultrahigh-resolution hybrid quadrupole FTICR instrument has been provided. PMID:24300588

  19. Structural characterisation of tyrosine-nitrated peptides by ultraviolet and infrared matrix-assisted laser desorption/ionisation Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Petre, Brínduşa-Alina; Youhnovski, Nikolay; Lukkari, Juho; Weber, Reinhold; Przybylski, Michael

    2005-01-01

    Nitration of tyrosine residues in proteins may occur in cells upon oxidative stress and inflammation processes mediated through generation of reactive nitroxyl from peroxynitrite. Tyrosine nitration from oxidative pathways may generate cytotoxic species that cause protein dysfunction and pathogenesis. A number of protein nitrations in vivo have been reported and some specific Tyrosine nitration sites have been recently identified using mass spectrometric methods. High-resolution Fourier transform ion cyclotron resonance mass spectrometry (MALDI) FT-ICR-MS) is shown here to be a highly efficient method in the determination of protein nitrations. Following the identification of nitration of the catalytic site Tyr-430 residue of bovine prostacyclin synthase, we synthesised several model peptides containing both unmodified tyrosine and 3-nitro-tyrosine residues, using solid-phase peptide synthesis (SPPS). The structures of the nitrotyrosine peptides were characterised both by ESI- and by matrix-assisted laser desorption/ionisation (MALDI)-FT-ICR-MS, using a standard ultraviolet (UV) nitrogen nitrogen laser and a 2.97 microm Nd-YAG infrared laser. Using UV-MALDI-MS, 3-nitrotyrosyl-peptides were found to undergo extensive photochemical fragmentation at the nitrophenyl group, which may hamper or prevent the unequivocal identification of Tyr-nitrations in cellular proteins. In contrast, infrared-MALDI-FT-ICR-MS did not produce fragmentation of molecular ions of Tyr-nitrated peptides. PMID:16322657

  20. Dithranol as a matrix for matrix assisted laser desorption/ionization imaging on a fourier transform ion cyclotron resonance mass spectrometer.

    PubMed

    Le, Cuong H; Han, Jun; Borchers, Christoph H

    2013-01-01

    Mass spectrometry imaging (MSI) determines the spatial localization and distribution patterns of compounds on the surface of a tissue section, mainly using MALDI (matrix assisted laser desorption/ionization)-based analytical techniques. New matrices for small-molecule MSI, which can improve the analysis of low-molecular weight (MW) compounds, are needed. These matrices should provide increased analyte signals while decreasing MALDI background signals. In addition, the use of ultrahigh-resolution instruments, such as Fourier transform ion cyclotron resonance (FTICR) mass spectrometers, has the ability to resolve analyte signals from matrix signals, and this can partially overcome many problems associated with the background originating from the MALDI matrix. The reduction in the intensities of the metastable matrix clusters by FTICR MS can also help to overcome some of the interferences associated with matrix peaks on other instruments. High-resolution instruments such as the FTICR mass spectrometers are advantageous as they can produce distribution patterns of many compounds simultaneously while still providing confidence in chemical identifications. Dithranol (DT; 1,8-dihydroxy-9,10-dihydroanthracen-9-one) has previously been reported as a MALDI matrix for tissue imaging. In this work, a protocol for the use of DT for MALDI imaging of endogenous lipids from the surfaces of mammalian tissue sections, by positive-ion MALDI-MS, on an ultrahigh-resolution hybrid quadrupole FTICR instrument has been provided. PMID:24300588

  1. Petroleomic Analysis of Bio- Oils from the Fast Pyrolysis or Biomass: Laser Desorption Ionization-Linear Ion Trap-Orbitrap mass Spectrometry Approach

    SciTech Connect

    Smith, Erica A.; Lee, Young Jin

    2010-08-23

    Fast pyrolysis of biomass produces bio-oils that can be upgraded into biofuels. Despite similar physical properties to petroleum, the chemical properties of bio-oils are quite different and their chemical compositions, particularly those of non-volatile compounds, are not well-known. Here, we report the first time attempt at analyzing bio-oils using high-resolution mass spectrometry (MS), which employed laser desorption ionization-linear ion trap-Orbitrap MS. Besides a few limitations, we could determine chemical compositions for over 100 molecular compounds in a bio-oil sample produced from the pyrolysis of a loblolly pine tree. These compounds consist of 3-6 oxygens and 9-17 double-bond equivalents (DBEs). Among those, O{sub 4} compounds with a DBE of 9-13 were most abundant. Unlike petroleum oils, the lack of nearby molecules within a {+-}2 Da mass window for major components enabled clear isolation of precursor ions for subsequent MS/MS structural investigations. Petroleomic analysis and a comparison to low-mass components in hydrolytic lignin suggest that they are dimers and trimers of depolymerized lignin.

  2. Utilization of Site-Specific Recombination in Biopharmaceutical Production

    PubMed Central

    Ahmadi, Maryam; Damavandi, Narges; Akbari, Mohammad Reza; Davami, Fatemeh

    2016-01-01

    Mammalian expression systems, due to their capacity in post-translational modification, are preferred systems for biopharmaceutical protein production. Several recombinant protein systems have been introduced to the market, most of which are under clinical development. In spite of significant improvements such as cell line engineering, introducing novel expression methods, gene silencing and process development, expression level is unpredictable and unstable because of the random location of integration in the genome. Site-specific recombination techniques are capable of producing stable and high producer clonal cells; therefore, they are gaining more importance in the biopharmaceutical production. Site-specific recombination methods increase the recombinant protein production by specifically inserting a vector at a locus with specific expression trait. The present review focused on the latest developments in site-specific recombination techniques, their specific features and comparisons. PMID:26602035

  3. Combined Approaches to Site-Specific Modification of RNA

    PubMed Central

    Chow, Christine S.; Mahto, Santosh K.; Lamichhane, Tek N.

    2008-01-01

    Both natural and unnatural modifications in RNA are of interest to biologists and chemists. More than 100 different analogs of the four standard RNA nucleosides have been identified in nature. Unnatural modifications are useful for structure and mechanistic studies of RNA. This Review highlights chemical, enzymatic, and combined (semisynthesis) approaches to generate site-specifically modified RNAs. The availability of these methods for site-specific modifications of RNAs of all sizes is important in order to study the relationships between RNA chemical composition, structure, and function. PMID:18177002

  4. The role of physical and chemical properties of Pd nanostructured materials immobilized on inorganic carriers on ion formation in atmospheric pressure laser desorption/ionization mass spectrometry.

    PubMed

    Silina, Yuliya E; Koch, Marcus; Volmer, Dietrich A

    2014-06-01

    Fundamental parameters influencing the ion-producing efficiency of palladium nanostructures (nanoparticles [Pd-NP], nanoflowers, nanofilms) during laser irradiation were studied in this paper. The nanostructures were immobilized on the surface of different solid inorganic carrier materials (porous and mono-crystalline silicon, anodic porous aluminum oxide, glass and polished steel) by using classical galvanic deposition, electroless local deposition and sputtering. It was the goal of this study to investigate the influence of both the nanoparticular layer as well as the carrier material on ion production for selected analyte molecules. Our experiments demonstrated that the dimensions of the synthesized nanostructures, the thickness of the active layers, surface disorders, thermal conductivity and physically or chemically adsorbed water influenced signal intensities of analyte ions during surface-assisted laser desorption/ionization (SALDI) while no effects such as plasmon resonance, photoelectric effect or catalytic activity were expected to occur. Excellent LDI abilities were seen for Pd-NPs immobilized on steel, while Pd nanoflowers on porous silicon exhibited several disadvantages; viz, strong memory effects, dependency of the analytical signal on amount of physically and chemically adsorbed water inside porous carrier, reduced SALDI activity from unstable connections between Pd and semiconductor material, decrease of the melting point of pure silicon after Pd immobilization and resulting strong laser ablation of metal/semiconductor complex, as well as significantly changed surface morphology after laser irradiation. The analytical performance of Pd-NP/steel was further improved by applying a hydrophobic coating to the steel surface before galvanic deposition. This procedure increased the distance between Pd-NPs, thus reducing thermal stress upon LDI; it simultaneously decreased spot sizes of deposited sample solutions. PMID:24913399

  5. Evidence for phosphorylation of serine 753 in CFTR using a novel metal-ion affinity resin and matrix-assisted laser desorption mass spectrometry.

    PubMed Central

    Neville, D. C.; Rozanas, C. R.; Price, E. M.; Gruis, D. B.; Verkman, A. S.; Townsend, R. R.

    1997-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) gene encodes an apical membrane Cl- channel regulated by protein phosphorylation. To identify cAMP-dependent protein kinase (PKA)-phosphorylated residues in full-length CFTR, immobilized metal-ion affinity chromatography (IMAC) was used to selectively purify phosphopeptides. The greater specificity of iron-loaded (Fe3+) nitrilotriacetic (NTA). Sepharose compared to iminodiacetic acid (IDA) metal-chelating matrices was demonstrated using a PKA-phosphorylated recombinant NBD1-R protein from CFTR. Fe(3+)-loaded NTA Sepharose preferentially bound phosphopeptides, whereas acidic and poly-His-containing peptides were co-purified using the conventional IDA matrices. IMAC using NTA Sepharose enabled the selective recovery of phosphopeptides and identification of phosphorylated residues from a complex proteolytic digest. Phosphopeptides from PKA-phosphorylated full-length CFTR, generated in Hi5 insect cells using a baculovirus expression system, were purified using NTA Sepharose. Phosphopeptides were identified using matrix-assisted laser desorption mass spectrometry (MALDI/MS) with post-source decay (PSD) analysis and collision-induced dissociation (CID) experiments. Phosphorylated peptides were identified by mass and by the metastable loss of HPO3 and H3PO4 from the parent ions. Peptide sequence and phosphorylation at CFTR residues 660Ser, 737Ser, and 795Ser were confirmed using MALDI/PSD analysis. Peptide sequences and phosphorylation at CFTR residues 700Ser, 712Ser, 768Ser, and 813Ser were deduced from peptide mass, metastable fragment ion formation, and PKA consensus sequences. Peptide sequence and phosphorylation at residue 753Ser was confirmed using MALDI/CID analysis. This is the first report of phosphorylation of 753Ser in full-length CFTR. PMID:9385646

  6. Delineating site-specific management units with proximal sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conventional farming uniformly manages fields with no consideration for spatial variability. This causes reduced productivity, misuse of finite resources (e.g., water and fertilizer), and detriment impacts on the environment. Site-specific management units (SSMUs) have been proposed as a means of ...

  7. Multispectral Imaging Technology for Site-Specific Crop Fertilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural fields are variable and require site-specific crop management. Nitrogen (N) is an essential nutrient required for plant growth and is a major component of the chlorophyll molecule enhancing photosynthesis. However, excessive N fertilizer leaches into groundwater and creates serious envi...

  8. Uncertainty Analysis with Site Specific Groundwater Models: Experiences and Observations

    SciTech Connect

    Brewer, K.

    2003-07-15

    Groundwater flow and transport predictions are a major component of remedial action evaluations for contaminated groundwater at the Savannah River Site. Because all groundwater modeling results are subject to uncertainty from various causes; quantification of the level of uncertainty in the modeling predictions is beneficial to project decision makers. Complex site-specific models present formidable challenges for implementing an uncertainty analysis.

  9. Wireless Site-specific Irrigation - The Future of Intelligent Agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless site-specific irrigation system was developed with a distributed wireless sensor network. The system allows growers to remotely access field conditions and an irrigation operation at the home or office via wireless radio communication, directing individual sprinklers on how much water to ...

  10. Site-Specific GlcNAcylation of Human Erythrocyte Proteins

    PubMed Central

    Wang, Zihao; Park, Kyoungsook; Comer, Frank; Hsieh-Wilson, Linda C.; Saudek, Christopher D.; Hart, Gerald W.

    2009-01-01

    OBJECTIVE—O-linked N-acetylglucosamine (O-GlcNAc) is upregulated in diabetic tissues and plays a role in insulin resistance and glucose toxicity. Here, we investigated the extent of GlcNAcylation on human erythrocyte proteins and compared site-specific GlcNAcylation on erythrocyte proteins from diabetic and normal individuals. RESEARCH DESIGN AND METHODS—GlcNAcylated erythrocyte proteins or GlcNAcylated peptides were tagged and selectively enriched by a chemoenzymatic approach and identified by mass spectrometry. The enrichment approach was combined with solid-phase chemical derivatization and isotopic labeling to detect O-GlcNAc modification sites and to compare site-specific O-GlcNAc occupancy levels between normal and diabetic erythrocyte proteins. RESULTS—The enzymes that catalyze the cycling (addition and removal) of O-GlcNAc were detected in human erythrocytes. Twenty-five GlcNAcylated erythrocyte proteins were identified. Protein expression levels were compared between diabetic and normal erythrocytes. Thirty-five O-GlcNAc sites were reproducibly identified, and their site-specific O-GlcNAc occupancy ratios were calculated. CONCLUSIONS—GlcNAcylation is differentially regulated at individual sites on erythrocyte proteins in response to glycemic status. These data suggest not only that site-specific O-GlcNAc levels reflect the glycemic status of an individual but also that O-GlcNAc site occupancy on erythrocyte proteins may be eventually useful as a diagnostic tool for the early detection of diabetes. PMID:18984734

  11. Evaluation of potential water conservation using site-specific irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the advent of site-specific variable-rate irrigation (VRI) systems, irrigation can be spatially managed within sub-field-sized zones. Spatial irrigation management can optimize spatial water use efficiency and may conserve water. Spatial VRI systems are currently being managed by consultants ...

  12. Adoption of site-specific variable rate sprinkler irrigation systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than twenty years of private and public research on site-specific variable-rate sprinkler irrigation (SS-VRI) technology has resulted in limited commercial adoption of the technology. Competing patents, liability and proprietary software have affected industry’s willingness to move into a new t...

  13. Invasive Weed Management Is Site-Specific Weed Management.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific weed management in crops and invasive weed management in natural lands and rangelands appear to be unrelated research areas but there are many connections in the research problems, approaches and solutions. An obvious link is technology. The technology of precision agriculture - GPS, ...

  14. Confident Assignment of Site-Specific Glycosylation in Complex Glycoproteins in a Single Step

    PubMed Central

    2015-01-01

    A glycoprotein may contain several sites of glycosylation, each of which is heterogeneous. As a consequence of glycoform diversity and signal suppression from nonglycosylated peptides that ionize more efficiently, typical reversed-phase LC–MS and bottom–up proteomics database searching workflows do not perform well for identification of site-specific glycosylation for complex glycoproteins. We present an LC–MS system for enrichment, separation, and analysis of glycopeptides from complex glycoproteins (>4 N-glycosylation sequons) in a single step. This system uses an online HILIC enrichment trap prior to reversed-phase C18-MS analysis. We demonstrated the effectiveness of the system using a set of glycoproteins including human transferrin (2 sequons), human alpha-1-acid glycoprotein (5 sequons), and influenza A virus hemagglutinin (9 sequons). The online enrichment renders glycopeptides the most abundant ions detected, thereby facilitating the generation of high-quality data-dependent tandem mass spectra. The tandem mass spectra exhibited product ions from both glycan and peptide backbone dissociation for a majority of the glycopeptides tested using collisionally activated dissociation that served to confidently assign site-specific glycosylation. We demonstrated the value of our system to define site-specific glycosylation using a hemagglutinin containing 9 N-glycosylation sequons from a single HILIC-C18-MS acquisition. PMID:25153361

  15. Identification of N-glycans from Ebola virus glycoproteins by matrix-assisted laser desorption/ionisation time-of-flight and negative ion electrospray tandem mass spectrometry

    PubMed Central

    Ritchie, Gayle; Harvey, David J.; Stroeher, Ute; Feldmann, Friederike; Feldmann, Heinz; Wahl-Jensen, Victoria; Royle, Louise; Dwek, Raymond A.; Rudd, Pauline M.

    2012-01-01

    The larger fragment of the transmembrane glycoprotein (GP1) and the soluble glycoprotein (sGP) of Ebola virus were expressed in human embryonic kidney cells and the secreted products were purified from the supernatant for carbohydrate analysis. The N-glycans were released with PNGase F from within sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS-PAGE) gels. Identification of the glycans was made with normal-phase high-performance liquid chromatography (HPLC), matrix-assisted laser desorption/ionisation mass spectrometry, negative ion electrospray ionisation fragmentation mass spectrometry and exoglycosidase digestion. Most glycans were complex bi-, tri-and tetra-antennary compounds with reduced amounts of galactose. No bisected compounds were detected. Triantennary glycans were branched on the 6-antenna; fucose was attached to the core GlcNAc residue. Sialylated glycans were present on sGP but were largely absent from GP1, the larger fragment of the transmembrane glycoprotein. Consistent with this was the generally higher level of processing of carbohydrates found on sGP as evidenced by a higher percentage of galactose and lower levels of high-mannose glycans than were found on GP1. These results confirm and expand previous findings on partial characterisation of the Ebola virus transmembrane glycoprotein. They represent the first detailed data on carbohydrate structures of the Ebola virus sGP. PMID:20131323

  16. Surface-Induced Dissociation of Ions Produced by Matrix-Assisted Laser Desorption Ionization in a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

    SciTech Connect

    Laskin, Julia; Beck, Kenneth M.; Hache, John J.; Futrell, Jean H.

    2004-01-15

    Intermediate pressure matrix assisted laser ionization (MALDI) source was constructed and interfaced with a 6T Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) specially configured for surface-induced dissociation (SID) studies.

  17. Detection of Biosignatures using Geomatrix-Assisted Laser Desorption/Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: Implications for the Search for Life in the Solar System

    NASA Astrophysics Data System (ADS)

    Richardson, C. D.; Kotler, J. M.; Hinman, N. W.; Scott, J. R.

    2008-12-01

    Detection of bio/organic signatures, defined as an organic structure produced by living organisms or derived from other biogenic organic compounds, is essential to investigating the origin and distribution of extant or extinct life in the solar system. In conjunction with mineralogical, inorganic, and isotopic data, the detection and identification of bio/organic signatures can assist in linking biochemical and geochemical processes. Geomatrix-assisted laser desorption/ionization (GALDI) in conjunction with a Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) is a proven method of obtaining bio/organic signatures from a range of geological materials. Sulfate salts were studied because they are found on Mars and Jovian satellites. The goal here was to determine (1) which combinations of bio/organic compounds and sulfate salts produced distinctive spectral signatures, and (2) the detection limit of the method. In these experiments, thenardite (Na2SO4) was mixed with stearic acid to determine the detection limit of GALDI-FTICR-MS, previously estimated to be 3 ppt, which corresponds to approximately 7 zeptomoles (10-21) per laser shot. All spectra were collected with little to no sample preparation and were acquired using a single laser shot. Unlike conventional analytical practices, the signal-to-noise ratio increased as the concentration of bio/organic compounds decreased relative to the mineral host. In combination with thenardite, aromatic amino acids were observed to undergo simple cation attachment ([M+Na]+) due to the π-bonded aromatic ring. Subsequent cation substitution of the carboxyl group led to formation of peaks representing double cation attachment ([M-H+Na]Na+). Spectra from naturally occurring thenardite and jarosite (XFe3(OH)6(SO4)2) revealed the presence of high mass cluster ions; analysis of their isotopic distribution suggested the presence of bio/organic compounds. High mass cluster ions, both organic and inorganic, readily

  18. Site-Specific Covalent Labeling of RNA by Enzymatic Transglycosylation.

    PubMed

    Alexander, Seth C; Busby, Kayla N; Cole, Christian M; Zhou, Cun Yu; Devaraj, Neal K

    2015-10-14

    We demonstrate the site-specific incorporation of nucleobase derivatives bearing fluorophores or affinity labels into a short RNA stem loop recognition motif by exchange of a guanine residue. The RNA-TAG (transglycosylation at guanosine) is carried out by a bacterial (E. coli) tRNA guanine transglycosylase (TGT), whose natural substrate is the nitrogenous base PreQ1. Remarkably, we have successfully incorporated large functional groups including biotin, BODIPY, thiazole orange, and Cy7 through a polyethylene glycol linker attached to the exocyclic amine of PreQ1. Larger RNAs, such as mRNA transcripts, can be site-specifically labeled if they possess the 17-nucleotide hairpin recognition motif. The RNA-TAG methodology could facilitate the detection and manipulation of RNA molecules by enabling the direct incorporation of functional artificial nucleobases using a simple hairpin recognition element. PMID:26393285

  19. Adapter Reagents for Protein Site Specific Dye Labeling

    PubMed Central

    Thompson, Darren A.; Evans, Eric G. B.; Kasza, Tomas; Millhauser, Glenn L.; Dawson, Philip E.

    2016-01-01

    Chemoselective protein labeling remains a significant challenge in chemical biology. Although many selective labeling chemistries have been reported, the practicalities of matching the reaction with appropriately functionalized proteins and labeling reagents is often a challenge. For example, we encountered the challenge of site specifically labeling the cellular form of the murine Prion protein with a fluorescent dye. To facilitate this labeling, a protein was expressed with site specific p-acetylphenylalanine. However, the utility of this aceto-phenone reactive group is hampered by the severe lack of commercially available aminooxy fluorophores. Here we outline a general strategy for the efficient solid phase synthesis of adapter reagents capable of converting maleimido-labels into aminooxy or azide functional groups that can be further tuned for desired length or solubility properties. The utility of the adapter strategy is demonstrated in the context of fluorescent labeling of the murine Prion protein through an adapted aminooxy-Alexa dye. PMID:24599728

  20. Chemoenzymatic Methods for Site-Specific Protein Modification

    PubMed Central

    Rabuka, David

    2010-01-01

    In the past decade, numerous chemical technologies have been developed to allow the site-specific post-translational modification of proteins. Traditionally covalent chemical protein modification has been accomplished by the attachment of synthetic groups to nucleophilic amino acids on protein surfaces. These chemistries, however, are rarely sufficiently selective to distinguish one residue within a literal sea of chemical functionality. One solution to this problem is to introduce a unique chemical handle into the target protein that is orthogonal to the remainder of the proteome. In practice, this handle can be a novel peptide sequence, which forms a “tag” that is selectively and irreversibly modified by enzymes. Furthermore, if the enzymes can tolerate substrate analogs, it becomes possible to engineer chemically modified proteins in a site-specific fashion. This review details the significant progress in creating techniques for the chemoenzymatic generation of protein-small molecule constructs and provides examples of novel applications of these methodologies. PMID:21030291

  1. Site-specific magnetization reversal studies of magnetite

    SciTech Connect

    Cady, A.; Haskel, D.; Lang, J. C.; Islam, Z.; Srajer, G.; Ankudinov, A.; Subias, G.; Garcia, J.

    2006-04-01

    The mechanism of magnetization reversal in magnetite (Fe{sub 3}O{sub 4}) single crystals was studied using site-specific magnetic sensitive diffraction anomalous near-edge structure. By exploiting the angular dependence of the cross section, we are able to show that the mechanism of reversal involves a mixture of coherent rotation and domain formation. The results reveal additional details to that provided by XMCD measurements, which average over nonequivalent sites.

  2. Site-specific gene modification by PNAs conjugated to psoralen.

    PubMed

    Kim, Ki-Hyun; Nielsen, Peter E; Glazer, Peter M

    2006-01-10

    DNA-binding molecules, including triplex-forming oligonucleotides (TFOs) and peptide nucleic acids (PNAs), can be utilized to introduce site-specific mutations or to promote recombination at selected genomic sites. To further evaluate the utility of PNAs for site-specific gene modification, we tested dimeric bis-PNAs conjugated to psoralen. These PNAs are designed to form a triplex-invasion complex within the supF reporter gene in an episomal shuttle vector and to direct site-specific photoadduct formation by the conjugated psoralen. The psoralen-bis-PNA conjugate was found to direct photoadduct formation to the intended 5'-TpA base step next to the PNA-binding site, and the photoadduct formation efficiency displayed both concentration and UVA irradiation dependence. The effect of PNA-targeted photoadducts in a mammalian system was tested by SV40-based shuttle vector assay. After in vitro binding, we found that photoadducts directed by PNAs conjugated to psoralen-induced mutations at frequencies in the range of 0.46%, 6.5-fold above the background. In a protocol for intracellular gene targeting in the episomal shuttle vector, the psoralen-PNA-induced mutation frequency was 0.13%, 3.5-fold higher than the background. Most of the induced mutations were deletions and single-base-pair substitutions at or adjacent to the targeted PNA-binding and photoadduct-formation sites. When the results are taken together, they demonstrate the ability of bis-PNAs conjugated with psoralen to mediate site-specific gene modification, and they further support the development of PNAs as tools for gene-targeting applications. PMID:16388608

  3. Pretargeted PET Imaging Using a Site-Specifically Labeled Immunoconjugate.

    PubMed

    Cook, Brendon E; Adumeau, Pierre; Membreno, Rosemery; Carnazza, Kathryn E; Brand, Christian; Reiner, Thomas; Agnew, Brian J; Lewis, Jason S; Zeglis, Brian M

    2016-08-17

    In recent years, both site-specific bioconjugation techniques and bioorthogonal pretargeting strategies have emerged as exciting technologies with the potential to improve the safety and efficacy of antibody-based nuclear imaging. In the work at hand, we have combined these two approaches to create a pretargeted PET imaging strategy based on the rapid and bioorthogonal inverse electron demand Diels-Alder reaction between a (64)Cu-labeled tetrazine radioligand ((64)Cu-Tz-SarAr) and a site-specifically modified huA33-trans-cyclooctene immunoconjugate ((ss)huA33-PEG12-TCO). A bioconjugation strategy that harnesses enzymatic transformations and strain-promoted azide-alkyne click chemistry was used to site-specifically append PEGylated TCO moieties to the heavy chain glycans of the colorectal cancer-targeting huA33 antibody. Preclinical in vivo validation studies were performed in athymic nude mice bearing A33 antigen-expressing SW1222 human colorectal carcinoma xenografts. To this end, mice were administered (ss)huA33-PEG12-TCO via tail vein injection and-following accumulation intervals of 24 or 48 h-(64)Cu-Tz-SarAr. PET imaging and biodistribution studies reveal that this strategy clearly delineates tumor tissue as early as 1 h post-injection (6.7 ± 1.7%ID/g at 1 h p.i.), producing images with excellent contrast and high tumor-to-background activity concentration ratios (tumor:muscle = 21.5 ± 5.6 at 24 h p.i.). Furthermore, dosimetric calculations illustrate that this pretargeting approach produces only a fraction of the overall effective dose (0.0214 mSv/MBq; 0.079 rem/mCi) of directly labeled radioimmunoconjugates. Ultimately, this method effectively facilitates the high contrast pretargeted PET imaging of colorectal carcinoma using a site-specifically modified immunoconjugate. PMID:27356886

  4. A general approach to site-specific antibody drug conjugates

    PubMed Central

    Tian, Feng; Lu, Yingchun; Manibusan, Anthony; Sellers, Aaron; Tran, Hon; Sun, Ying; Phuong, Trung; Barnett, Richard; Hehli, Brad; Song, Frank; DeGuzman, Michael J.; Ensari, Semsi; Pinkstaff, Jason K.; Sullivan, Lorraine M.; Biroc, Sandra L.; Cho, Ho; Schultz, Peter G.; DiJoseph, John; Dougher, Maureen; Ma, Dangshe; Dushin, Russell; Leal, Mauricio; Tchistiakova, Lioudmila; Feyfant, Eric; Gerber, Hans-Peter; Sapra, Puja

    2014-01-01

    Using an expanded genetic code, antibodies with site-specifically incorporated nonnative amino acids were produced in stable cell lines derived from a CHO cell line with titers over 1 g/L. Using anti-5T4 and anti-Her2 antibodies as model systems, site-specific antibody drug conjugates (NDCs) were produced, via oxime bond formation between ketones on the side chain of the incorporated nonnative amino acid and hydroxylamine functionalized monomethyl auristatin D with either protease-cleavable or noncleavable linkers. When noncleavable linkers were used, these conjugates were highly stable and displayed improved in vitro efficacy as well as in vivo efficacy and pharmacokinetic stability in rodent models relative to conventional antibody drug conjugates conjugated through either engineered surface-exposed or reduced interchain disulfide bond cysteine residues. The advantages of the oxime-bonded, site-specific NDCs were even more apparent when low–antigen-expressing (2+) target cell lines were used in the comparative studies. NDCs generated with protease-cleavable linkers demonstrated that the site of conjugation had a significant impact on the stability of these rationally designed prodrug linkers. In a single-dose rat toxicology study, a site-specific anti-Her2 NDC was well tolerated at dose levels up to 90 mg/kg. These experiments support the notion that chemically defined antibody conjugates can be synthesized in commercially relevant yields and can lead to antibody drug conjugates with improved properties relative to the heterogeneous conjugates formed by nonspecific chemical modification. PMID:24443552

  5. A general approach to site-specific antibody drug conjugates.

    PubMed

    Tian, Feng; Lu, Yingchun; Manibusan, Anthony; Sellers, Aaron; Tran, Hon; Sun, Ying; Phuong, Trung; Barnett, Richard; Hehli, Brad; Song, Frank; DeGuzman, Michael J; Ensari, Semsi; Pinkstaff, Jason K; Sullivan, Lorraine M; Biroc, Sandra L; Cho, Ho; Schultz, Peter G; DiJoseph, John; Dougher, Maureen; Ma, Dangshe; Dushin, Russell; Leal, Mauricio; Tchistiakova, Lioudmila; Feyfant, Eric; Gerber, Hans-Peter; Sapra, Puja

    2014-02-01

    Using an expanded genetic code, antibodies with site-specifically incorporated nonnative amino acids were produced in stable cell lines derived from a CHO cell line with titers over 1 g/L. Using anti-5T4 and anti-Her2 antibodies as model systems, site-specific antibody drug conjugates (NDCs) were produced, via oxime bond formation between ketones on the side chain of the incorporated nonnative amino acid and hydroxylamine functionalized monomethyl auristatin D with either protease-cleavable or noncleavable linkers. When noncleavable linkers were used, these conjugates were highly stable and displayed improved in vitro efficacy as well as in vivo efficacy and pharmacokinetic stability in rodent models relative to conventional antibody drug conjugates conjugated through either engineered surface-exposed or reduced interchain disulfide bond cysteine residues. The advantages of the oxime-bonded, site-specific NDCs were even more apparent when low-antigen-expressing (2+) target cell lines were used in the comparative studies. NDCs generated with protease-cleavable linkers demonstrated that the site of conjugation had a significant impact on the stability of these rationally designed prodrug linkers. In a single-dose rat toxicology study, a site-specific anti-Her2 NDC was well tolerated at dose levels up to 90 mg/kg. These experiments support the notion that chemically defined antibody conjugates can be synthesized in commercially relevant yields and can lead to antibody drug conjugates with improved properties relative to the heterogeneous conjugates formed by nonspecific chemical modification. PMID:24443552

  6. POLYMER DELIVERY SYSTEMS FOR SITE-SPECIFIC GENOME EDITING

    PubMed Central

    McNeer, Nicole Ali; Schleifman, Erica B.; Glazer, Peter M.; Saltzman, W. Mark

    2011-01-01

    Triplex-forming peptide nucleic acids (PNAs) can be used to coordinate the recombination of short 50–60 bp “donor DNA” fragments into genomic DNA, resulting in site-specific correction of genetic mutations or the introduction of advantageous genetic modifications. Site-specific gene editing in hematopoietic stem and progenitor cells (HSPCs) could result in the treatment or cure of inherited disorders of the blood such as β-thalassemia or sickle cell anemia. Gene editing in HSPCs and differentiated T cells could also help combat HIV infection by modifying the HIV co-receptor CCR5, which is necessary for R5-tropic HIV entry. However, translation of genome modification technologies to clinical practice is limited by challenges in intracellular delivery, especially in difficult-to-transfect hematolymphoid cells. Here, we review the use of engineered biodegradable polymer nanoparticles for site-specific genome editing in human hematopoietic cells, which represent a promising approach for ex vivo and in vivo gene therapy. PMID:21620910

  7. Site specific atomic polarizabilities in endohedral fullerenes and carbon onions

    SciTech Connect

    Zope, Rajendra R. Baruah, Tunna; Bhusal, Shusil; Basurto, Luis; Jackson, Koblar

    2015-08-28

    We investigate the polarizability of trimetallic nitride endohedral fullerenes by partitioning the total polarizability into site specific components. This analysis indicates that the polarizability of the endohedral fullerene is essentially due to the outer fullerene cage and has insignificant contribution from the encapsulated unit. Thus, the outer fullerene cages effectively shield the encapsulated clusters and behave like Faraday cages. The polarizability of endohedral fullerenes is slightly smaller than the polarizability of the corresponding bare carbon fullerenes. The application of the site specific polarizabilities to C{sub 60}@C{sub 240} and C{sub 60}@C{sub 180} onions shows that, compared to the polarizability of isolated C{sub 60} fullerene, the encapsulation of the C{sub 60} in C{sub 240} and C{sub 180} fullerenes reduces its polarizability by 75% and 83%, respectively. The differences in the polarizability of C{sub 60} in the two onions is a result of differences in the bonding (intershell electron transfer), fullerene shell relaxations, and intershell separations. The site specific analysis further shows that the outer atoms in a fullerene shell contribute most to the fullerene polarizability.

  8. Site specific atomic polarizabilities in endohedral fullerenes and carbon onions

    NASA Astrophysics Data System (ADS)

    Zope, Rajendra R.; Bhusal, Shusil; Basurto, Luis; Baruah, Tunna; Jackson, Koblar

    2015-08-01

    We investigate the polarizability of trimetallic nitride endohedral fullerenes by partitioning the total polarizability into site specific components. This analysis indicates that the polarizability of the endohedral fullerene is essentially due to the outer fullerene cage and has insignificant contribution from the encapsulated unit. Thus, the outer fullerene cages effectively shield the encapsulated clusters and behave like Faraday cages. The polarizability of endohedral fullerenes is slightly smaller than the polarizability of the corresponding bare carbon fullerenes. The application of the site specific polarizabilities to C60@C240 and C60@C180 onions shows that, compared to the polarizability of isolated C60 fullerene, the encapsulation of the C60 in C240 and C180 fullerenes reduces its polarizability by 75% and 83%, respectively. The differences in the polarizability of C60 in the two onions is a result of differences in the bonding (intershell electron transfer), fullerene shell relaxations, and intershell separations. The site specific analysis further shows that the outer atoms in a fullerene shell contribute most to the fullerene polarizability.

  9. Site specific atomic polarizabilities in endohedral fullerenes and carbon onions.

    PubMed

    Zope, Rajendra R; Bhusal, Shusil; Basurto, Luis; Baruah, Tunna; Jackson, Koblar

    2015-08-28

    We investigate the polarizability of trimetallic nitride endohedral fullerenes by partitioning the total polarizability into site specific components. This analysis indicates that the polarizability of the endohedral fullerene is essentially due to the outer fullerene cage and has insignificant contribution from the encapsulated unit. Thus, the outer fullerene cages effectively shield the encapsulated clusters and behave like Faraday cages. The polarizability of endohedral fullerenes is slightly smaller than the polarizability of the corresponding bare carbon fullerenes. The application of the site specific polarizabilities to C60@C240 and C60@C180 onions shows that, compared to the polarizability of isolated C60 fullerene, the encapsulation of the C60 in C240 and C180 fullerenes reduces its polarizability by 75% and 83%, respectively. The differences in the polarizability of C60 in the two onions is a result of differences in the bonding (intershell electron transfer), fullerene shell relaxations, and intershell separations. The site specific analysis further shows that the outer atoms in a fullerene shell contribute most to the fullerene polarizability. PMID:26328842

  10. MoS2/Ag nanohybrid: A novel matrix with synergistic effect for small molecule drugs analysis by negative-ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    PubMed

    Zhao, Yaju; Deng, Guoqing; Liu, Xiaohui; Sun, Liang; Li, Hui; Cheng, Quan; Xi, Kai; Xu, Danke

    2016-09-21

    This paper reports a facile synthesis of molybdenum disulfide nanosheets/silver nanoparticles (MoS2/Ag) hybrid and its use as an effective matrix in negative ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The nanohybrid exerts a strong synergistic effect, leading to high performance detection of small molecule analytes including amino acids, peptides, fatty acids and drugs. The enhancement of laser desorption/ionization (LDI) efficiency is largely attributed to the high surface roughness and large surface area for analyte adsorption, better dispersibility, increased thermal conductivity and enhanced UV energy absorption as compared to pure MoS2. Moreover, both Ag nanoparticles and the edge of the MoS2 layers function as deprotonation sites for proton capture, facilitating the charging process in negative ion mode and promoting formation of negative ions. As a result, the MoS2/Ag nanohybrid proves to be a highly attractive matrix in MALDI-TOF MS, with desired features such as high desorption/ionization efficiency, low fragmentation interference, high salt tolerance, and no sweet-spots for mass signal. These characteristic properties allowed for simultaneous analysis of eight different drugs and quantification of acetylsalicylic acid in the spiked human serum. This work demonstrates for the first time the fabrication and application of a novel MoS2/Ag hybrid, and provides a new platform for use in the rapid and high throughput analysis of small molecules by mass spectrometry. PMID:27590549

  11. Charge Assisted Laser Desorption/Ionization Mass Spectrometry of Droplets

    PubMed Central

    Jorabchi, Kaveh; Westphall, Michael S.; Smith, Lloyd M.

    2008-01-01

    We propose and evaluate a new mechanism to account for analyte ion signal enhancement in ultraviolet-laser desorption mass spectrometry of droplets in the presence of corona ions. Our new insights are based on timing control of corona ion production, laser desorption, and peptide ion extraction achieved by a novel pulsed corona apparatus. We demonstrate that droplet charging rather than gas-phase ion-neutral reactions is the major contributor to analyte ion generation from an electrically isolated droplet. Implications of the new mechanism, termed charge assisted laser desorption/ionization (CALDI), are discussed and contrasted to those of the laser desorption atmospheric pressure chemical ionization method (LD-APCI). It is also demonstrated that analyte ion generation in CALDI occurs with external electric fields about one order of magnitude lower than those needed for atmospheric pressure matrix assisted laser desorption/ionization or electrospray ionization of droplets. PMID:18387311

  12. Chemical tags for site-specific fluorescent labeling of biomolecules.

    PubMed

    Freidel, Christoph; Kaloyanova, Stefka; Peneva, Kalina

    2016-06-01

    This review focuses on the various approaches to covalently attach a chromophore to a biomolecule of interest in site-specific manner. Novel methods like inverse electron-demand Diels-Alder reaction, Pictet-Spengler ligation and enzyme tags like SNAP and Halo-tags are critically discussed and compared to established techniques like copper-free click reaction and native chemical ligation. Selected examples in which the tags have been exploited for in vitro or in vivo imaging are reviewed and evaluated. PMID:26969255

  13. Site Specific Probable Maximum Precipitation Estimates and Professional Judgement

    NASA Astrophysics Data System (ADS)

    Hayes, B. D.; Kao, S. C.; Kanney, J. F.; Quinlan, K. R.; DeNeale, S. T.

    2015-12-01

    State and federal regulatory authorities currently rely upon the US National Weather Service Hydrometeorological Reports (HMRs) to determine probable maximum precipitation (PMP) estimates (i.e., rainfall depths and durations) for estimating flooding hazards for relatively broad regions in the US. PMP estimates for the contributing watersheds upstream of vulnerable facilities are used to estimate riverine flooding hazards while site-specific estimates for small water sheds are appropriate for individual facilities such as nuclear power plants. The HMRs are often criticized due to their limitations on basin size, questionable applicability in regions affected by orographic effects, their lack of consist methods, and generally by their age. HMR-51 for generalized PMP estimates for the United States east of the 105th meridian, was published in 1978 and is sometimes perceived as overly conservative. The US Nuclear Regulatory Commission (NRC), is currently reviewing several flood hazard evaluation reports that rely on site specific PMP estimates that have been commercially developed. As such, NRC has recently investigated key areas of expert judgement via a generic audit and one in-depth site specific review as they relate to identifying and quantifying actual and potential storm moisture sources, determining storm transposition limits, and adjusting available moisture during storm transposition. Though much of the approach reviewed was considered a logical extension of HMRs, two key points of expert judgement stood out for further in-depth review. The first relates primarily to small storms and the use of a heuristic for storm representative dew point adjustment developed for the Electric Power Research Institute by North American Weather Consultants in 1993 in order to harmonize historic storms for which only 12 hour dew point data was available with more recent storms in a single database. The second issue relates to the use of climatological averages for spatially

  14. Rapid Profiling of Bovine and Human Milk Gangliosides by Matrix-Assisted Laser Desorption/Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    PubMed Central

    Lee, Hyeyoung; An, Hyun Joo; Lerno, Larry A.; German, J. Bruce; Lebrilla, Carlito B.

    2010-01-01

    Gangliosides are anionic glycosphingolipids widely distributed in vertebrate tissues and fluids. Their structural and quantitative expression patterns depend on phylogeny and are distinct down to the species level. In milk, gangliosides are exclusively associated with the milk fat globule membrane. They may participate in diverse biological processes but more specifically to host-pathogen interactions. However, due to the molecular complexities, the analysis needs extensive sample preparation, chromatographic separation, and even chemical reaction, which makes the process very complex and time-consuming. Here, we describe a rapid profiling method for bovine and human milk gangliosides employing matrix-assisted desorption/ionization (MALDI) Fourier transform ion cyclotron resonance (FTICR) mass spectrometry (MS). Prior to the analyses of biological samples, milk ganglioside standards GM3 and GD3 fractions were first analyzed in order to validate this method. High mass accuracy and high resolution obtained from MALDI FTICR MS allow for the confident assignment of chain length and degree of unsaturation of the ceramide. For the structural elucidation, tandem mass spectrometry (MS/MS), specifically as collision-induced dissociation (CID) and infrared multiphoton dissociation (IRMPD) were employed. Complex ganglioside mixtures from bovine and human milk were further analyzed with this method. The samples were prepared by two consecutive chloroform/methanol extraction and solid phase extraction. We observed a number of differences between bovine milk and human milk. The common gangliosides in bovine and human milk are NeuAc-NeuAc-Hex-Hex-Cer (GD3) and NeuAc-Hex-Hex-Cer (GM3); whereas, the ion intensities of ganglioside species are different between two milk samples. Kendrick mass defect plot yields grouping of ganglioside peaks according to their structural similarities. Gangliosides were further probed by tandem MS to confirm the compositional and structural assignments

  15. Experimental Investigations of the Internal Energy of Molecules Evaporated via Laser-induced Acoustic Desorption into a Fourier-transform Ion Cyclotron Resonance Mass Spectrometer (LIAD/FT-ICR)

    PubMed Central

    Shea, Ryan C.; Petzold, Christopher J.; Liu, Ji-ang; Kenttämaa, Hilkka I.

    2008-01-01

    The internal energy of neutral gas-phase organic and biomolecules, evaporated by means of laser-induced acoustic desorption (LIAD) into a Fourier-transform ion cyclotron resonance mass spectrometer (FT-ICR), was investigated through several experimental approaches. The desorbed molecules were demonstrated not to undergo degradation during the desorption process by collecting LIAD-evaporated molecules and subjecting them to analysis by electrospray ionization/quadrupole ion trap mass spectrometry. Previously established gas-phase basicity (GB) values were remeasured for LIAD-evaporated organic molecules and biomolecules with the use of the bracketing method. No endothermic reactions were observed. The remeasured basicity values are in close agreement with the values reported in the literature. The amount of internal energy deposited during LIAD is concluded to be less than a few kcal/mol. Chemical ionization with a series of proton transfer reagents was employed to obtain a breakdown curve for a protonated dipeptide, val-pro, evaporated by LIAD. Comparison of this breakdown curve with a previously published analogous curve obtained by using substrate-assisted laser desorption (SALD) to evaporate the peptide suggests that the molecules evaporated via LIAD have less internal energy than those evaporated via SALD. PMID:17263513

  16. Site-specific calibration of the Hanford personnel neutron dosimeter

    SciTech Connect

    Endres, A.W.; Brackenbush, L.W.; Baumgartner, W.V.; Rathbone, B.A.

    1994-10-01

    A new personnel dosimetry system, employing a standard Hanford thermoluminescent dosimeter (TLD) and a combination dosimeter with both CR-39 nuclear track and TLD-albedo elements, is being implemented at Hanford. Measurements were made in workplace environments in order to verify the accuracy of the system and establish site-specific factors to account for the differences in dosimeter response between the workplace and calibration laboratory. Neutron measurements were performed using sources at Hanford`s Plutonium Finishing Plant under high-scatter conditions to calibrate the new neutron dosimeter design to site-specific neutron spectra. The dosimeter was also calibrated using bare and moderated {sup 252}Cf sources under low-scatter conditions available in the Hanford Calibration Laboratory. Dose equivalent rates in the workplace were calculated from spectrometer measurements using tissue equivalent proportional counter (TEPC) and multisphere spectrometers. The accuracy of the spectrometers was verified by measurements on neutron sources with calibrations directly traceable to the National Institute of Standards and Technology (NIST).

  17. Site Specific Genetic Incorporation of Azidophenylalanine in Schizosaccharomyces pombe

    PubMed Central

    Shao, Nan; Singh, N. Sadananda; Slade, Susan E.; Jones, Alexandra M. E.; Balasubramanian, Mohan K.

    2015-01-01

    The diversity of protein functions is impacted in significant part by the chemical properties of the twenty amino acids, which are used as building blocks for nearly all proteins. The ability to incorporate unnatural amino acids (UAA) into proteins in a site specific manner can vastly expand the repertoire of protein functions and also allows detailed analysis of protein function. In recent years UAAs have been incorporated in a site-specific manner into proteins in a number of organisms. In nearly all cases, the amber codon is used as a sense codon, and an orthogonal tRNA/aminoacyl-tRNA synthetase (RS) pair is used to generate amber suppressing tRNAs charged with the UAA. In this work, we have developed tools to incorporate the cross-linking amino acid azido-phenylalanine (AzF) through the use of bacterial tRNATyr and a modified version of TyrRS, AzFRS, in Schizosaccharomyces pombe, which is an attractive model organism for the study of cell behavior and function. We have incorporated AzF into three different proteins. We show that the majority of AzF is modified to amino-phenyl alanine, but protein cross-linking was still observed. These studies set the stage for exploitation of this new technology for the analysis of S. pombe proteins. PMID:26597962

  18. Site-specific antibody drug conjugates for cancer therapy

    PubMed Central

    Panowksi, Siler; Bhakta, Sunil; Raab, Helga; Polakis, Paul; Junutula, Jagath R

    2014-01-01

    Antibody therapeutics have revolutionized the treatment of cancer over the past two decades. Antibodies that specifically bind tumor surface antigens can be effective therapeutics; however, many unmodified antibodies lack therapeutic activity. These antibodies can instead be applied successfully as guided missiles to deliver potent cytotoxic drugs in the form of antibody drug conjugates (ADCs). The success of ADCs is dependent on four factors—target antigen, antibody, linker, and payload. The field has made great progress in these areas, marked by the recent approval by the US Food and Drug Administration of two ADCs, brentuximab vedotin (Adcetris®) and ado-trastuzumab emtansine (Kadcyla®). However, the therapeutic window for many ADCs that are currently in pre-clinical or clinical development remains narrow and further improvements may be required to enhance the therapeutic potential of these ADCs. Production of ADCs is an area where improvement is needed because current methods yield heterogeneous mixtures that may include 0–8 drug species per antibody molecule. Site-specific conjugation has been recently shown to eliminate heterogeneity, improve conjugate stability, and increase the therapeutic window. Here, we review and describe various site-specific conjugation strategies that are currently used for the production of ADCs, including use of engineered cysteine residues, unnatural amino acids, and enzymatic conjugation through glycotransferases and transglutaminases. In addition, we also summarize differences among these methods and highlight critical considerations when building next-generation ADC therapeutics. PMID:24423619

  19. Site-specific antibody drug conjugates for cancer therapy.

    PubMed

    Panowski, Siler; Bhakta, Sunil; Raab, Helga; Polakis, Paul; Junutula, Jagath R

    2014-01-01

    Antibody therapeutics have revolutionized the treatment of cancer over the past two decades. Antibodies that specifically bind tumor surface antigens can be effective therapeutics; however, many unmodified antibodies lack therapeutic activity. These antibodies can instead be applied successfully as guided missiles to deliver potent cytotoxic drugs in the form of antibody drug conjugates (ADCs). The success of ADCs is dependent on four factors--target antigen, antibody, linker, and payload. The field has made great progress in these areas, marked by the recent approval by the US Food and Drug Administration of two ADCs, brentuximab vedotin (Adcetris) and ado-trastuzumab emtansine (Kadcyla). However, the therapeutic window for many ADCs that are currently in pre-clinical or clinical development remains narrow and further improvements may be required to enhance the therapeutic potential of these ADCs. Production of ADCs is an area where improvement is needed because current methods yield heterogeneous mixtures that may include 0-8 drug species per antibody molecule. Site-specific conjugation has been recently shown to eliminate heterogeneity, improve conjugate stability, and increase the therapeutic window. Here, we review and describe various site-specific conjugation strategies that are currently used for the production of ADCs, including use of engineered cysteine residues, unnatural amino acids, and enzymatic conjugation through glycotransferases and transglutaminases. In addition, we also summarize differences among these methods and highlight critical considerations when building next-generation ADC therapeutics. PMID:24423619

  20. Site-specific analysis of dielectric properties of finite systems.

    SciTech Connect

    Jackson, K.; Yang, M.; Jellinek, J.; Chemistry; Central Michigan Univ.

    2007-12-06

    A new scheme for decomposing the total dipole moment and polarizability of a system into site-specific contributions is presented. The scheme is based on partitioning the system volume into cells associated with its atoms or groups of atoms. The site-specific dipole moments and polarizabilities are computed from the charge densities within the individual cells and the responses of these densities to an external electric field. These dipole moments and polarizabilities are further partitioned into local/dipole and charge-transfer components. The utility of the scheme is illustrated through analysis of the structure-/shape- and size-specific aspects of the dipole moments and polarizabilities of silicon clusters. It is shown that the polarizabilities associated with the individual constituent Si atoms vary considerably with the structure/shape of the cluster and the location of the atom or site within a given structure. Surface atoms, and especially those at edges, have larger polarizabilities than interior atoms. The overall contribution of the charge-transfer components to the total cluster polarizability increases with the cluster size. Finally, the anisotropy of the total polarizability correlates with the anisotropy of the cluster shape, and the charge-transfer component is the part dominantly responsible for the polarizability anisotropy.

  1. Site-specific features influence sediment stability of intertidal flats

    NASA Astrophysics Data System (ADS)

    Defew, Emma C.; Tolhurst, Trevor J.; Paterson, David M.

    The factors that influence the sediment stability and the transport of estuarine mudflats are not yet fully understood but knowledge of them is essential in coastal engineering applications and pollution ecology studies. The suggestion that variation in predictive models of sediment stability might be due to site-specific characteristics is investigated using data from four estuarine mudflats (Eden Estuary, Scotland, the Biezelingsche Ham, Zandkreek, and Molenplaat mudflats in The Netherlands). These estuaries differ in their environmental conditions, macrofaunal species composition and local features (e.g. Enteromorpha mats, migratory biofilms). Stable and unstable sediments were compared, and mean chlorophyll-a concentrations and granulometry of the sediments were significantly different between the two groups. Step-wise multiple linear regressions were applied to the sediment stability data of all sites to establish the influences on erosion threshold of microphytobenthic biomass, water content, granulometry, organic carbon content and the abundance of dominant macrofaunal species. The stability of each site was influenced by different factors. Sediment stability of the Eden Estuary was affected by the Enteromorpha bloom; Biezelingsche Ham was influenced by the highly migratory nature of the diatom biofilms and the abundance of Corophium volutator; the polychaete worm Arenicola marina had a net negative effect on sediment stability of the Zandkreek; and the Molenplaat was influenced by microphytobenthic biomass. This research highlights the need for site-specific calibration of models and suggests that a universal proxy parameter for sediment stability is unlikely to be obtained.

  2. Structure and Composition of Air-Plane Soots and Surrogates Analyzed by Raman Spectroscopy and Laser/Ions Desorption Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ortega, Ismael; Chazallon, Bertrand; Carpentier, Yvain; Irimiea, Cornelia; Focsa, Cristian; Ouf, François-Xavier; Salm, François; Delhaye, David; Gaffié, Daniel; Yon, Jérôme

    2015-04-01

    Aviation alters the composition of the atmosphere globally and can thus drive climate change and ozone depletion [1]. An aircraft exhaust plume contains species emitted by the engines, species formed in the plume from the emitted species and atmospheric species that become entrained into the plume. The majority of emitted species (gases and soot particles) are produced by the combustion of kerosene with ambient air in the combustion chamber of the engine. Emissions of soot particles by air-planes produce persistent contrails in the upper troposphere in ice-supersaturated air masses that contribute to cloudiness and impact the radiative properties of the atmosphere. These aerosol-cloud interactions represent one of the largest sources of uncertainty in global climate models [2]. Though the formation of atmospheric ice particles has been studied since many years [3], there are still numerous opened questions on nucleation properties of soot particles [4], as the ice nucleation experiments showed a large spread in results depending on the nucleation mode chosen and origin of the soot produced. Most likely one of the reasons behind these discrepancies resides in the different physico-chemical properties (composition, structure) of soot particles produced in different conditions, e.g. with respect to fuel or combustion techniques. In this work, we use Raman microscopy (266, 514 and 785 nm excitation) and ablation techniques (SIMS, Secondary Ions Mass Spectrometry, and Laser Desorption Mass Spectrometry) to characterize soot particles produced from air-plane at different engine regimes simulating a landing and taking-off (LTO) cycle. First, the spectral parameters of the first-order Raman band of various soot samples, collected from three different sources in the frame of the MERMOSE project (http://mermose.onera.fr/): PowerJet SaM-146 turbofan (four engine regimes), CAST generator (propane fuel, four different global equivalence ratios), and Kerosene laboratory flame

  3. Analysis of the site-specific carbon isotope composition of propane by gas source isotope ratio mass spectrometer

    NASA Astrophysics Data System (ADS)

    Piasecki, Alison; Sessions, Alex; Lawson, Michael; Ferreira, A. A.; Neto, E. V. Santos; Eiler, John M.

    2016-09-01

    Site-specific isotope ratio measurements potentially provide valuable information about the formation and degradation of complex molecules-information that is lost in conventional bulk isotopic measurements. Here we discuss the background and possible applications of such measurements, and present a technique for studying the site-specific carbon isotope composition of propane at natural abundance based on mass spectrometric analysis of the intact propane molecule and its fragment ions. We demonstrate the feasibility of this approach through measurements of mixtures of natural propane and propane synthesized with site-specific 13C enrichment, and we document the limits of precision of our technique. We show that mass balance calculations of the bulk δ13C of propane based on our site-specific measurements is generally consistent with independent constraints on bulk δ13C. We further demonstrate the accuracy of the technique, and illustrate one of its simpler applications by documenting the site-specific carbon isotope signature associated with gas phase diffusion of propane, confirming that our measurements conform to the predictions of the kinetic theory of gases. This method can be applied to propane samples of moderate size (tens of micromoles) isolated from natural gases. Thus, it provides a means of studying the site-specific stable isotope systematics of propane at natural isotope abundances on sample sizes that are readily recovered from many natural environments. This method may also serve as a model for future techniques that apply high-resolution mass spectrometry to study the site-specific isotopic distributions of larger organic molecules, with potential applications to biosynthesis, forensics and other geochemical subjects.

  4. Site-Specific Genome Engineering in Human Pluripotent Stem Cells.

    PubMed

    Merkert, Sylvia; Martin, Ulrich

    2016-01-01

    The possibility to generate patient-specific induced pluripotent stem cells (iPSCs) offers an unprecedented potential of applications in clinical therapy and medical research. Human iPSCs and their differentiated derivatives are tools for diseases modelling, drug discovery, safety pharmacology, and toxicology. Moreover, they allow for the engineering of bioartificial tissue and are promising candidates for cellular therapies. For many of these applications, the ability to genetically modify pluripotent stem cells (PSCs) is indispensable, but efficient site-specific and safe technologies for genetic engineering of PSCs were developed only recently. By now, customized engineered nucleases provide excellent tools for targeted genome editing, opening new perspectives for biomedical research and cellular therapies. PMID:27347935

  5. Cre-mediated site-specific recombination in zebrafish embryos.

    PubMed

    Thummel, Ryan; Burket, Christopher T; Brewer, Jeffrey L; Sarras, Michael P; Li, Li; Perry, Martin; McDermott, Jeffrey P; Sauer, Brian; Hyde, David R; Godwin, Alan R

    2005-08-01

    Cre-mediated site-specific recombination has become an invaluable tool for manipulation of the murine genome. The ability to conditionally activate gene expression or to generate chromosomal alterations with this same tool would greatly enhance zebrafish genetics. This study demonstrates that the HSP70 promoter can be used to inducibly control expression of an enhanced green fluorescent protein (EGFP) -Cre fusion protein. The EGFP-Cre fusion protein is capable of promoting recombination between lox sites in injected plasmids or in stably inherited transgenes as early as 2 hr post-heat shock induction. Finally, the levels of Cre expression achieved in a transgenic fish line carrying the HSP70-EGFP-cre transgene are compatible with viability and both male and female transgenic fish are fertile subsequent to induction of EGFP-Cre expression. Hence, our data suggests that Cre-mediated recombination is a viable means of manipulating gene expression in zebrafish. PMID:15977183

  6. Measuring fluctuations in shear stretched DNAs using site specific labeling

    NASA Astrophysics Data System (ADS)

    Price, Allen; Graham, Thomas; Loparo, Joseph; Eaves, Joel

    2012-02-01

    We report a new technique for measuring the internal dynamics of surface tethered DNAs in shear flow. Previous studies have used end labeling or intercolating dyes which label the entire length of the DNA. Neither prior method can resolve the internal longitudinal fluctuations of the DNA. Our technique accomplishes this by site specific labeling of five sites in lambda phage DNA using EcoRI labeled with fluorescent quantum dots. We used our technique to determine the two point cross correlation functions of the longitudinal and transverse fluctuations of the DNA under shear flow. Our technique allows us to test current models of the non-equilibrium fluctuations of DNA in shear flow in a way previously inaccessible.

  7. Methods for generating phosphorylation site-specific immunological reagents

    DOEpatents

    Anderson, Carl W.; Appella, Ettore; Sakaguchi, Kazuyasu

    2001-01-01

    The present invention provides methods for generating phosphorylation site-specific immunological reagents. More specifically, a phosphopeptide mimetic is incorporated into a polypeptide in place of a phosphorylated amino acid. The polypeptide is used as antigen by standard methods to generate either monoclonal or polyclonal antibodies which cross-react with the naturally phosphorylated polypeptide. The phosphopeptide mimetic preferably contains a non-hydrolyzable linkage from the appropriate carbon atom of the amino acid residue to a phosphate group. A preferred linkage is a CF.sub.2 group. Such a linkage is used to generate the phosphoserine mimetic F.sub.2 Pab, which is incorporated into a polypeptide sequence derived from p53 to produce antibodies which recognize a specific phosphorylation state of p53. A CF.sub.2 group linkage is also used to produce the phosphothreonine mimetic F.sub.2 Pmb, and to produce the phosphotyrosine mimetic, F.sub.2 Pmp.

  8. Site-Specific Genome Engineering in Human Pluripotent Stem Cells

    PubMed Central

    Merkert, Sylvia; Martin, Ulrich

    2016-01-01

    The possibility to generate patient-specific induced pluripotent stem cells (iPSCs) offers an unprecedented potential of applications in clinical therapy and medical research. Human iPSCs and their differentiated derivatives are tools for diseases modelling, drug discovery, safety pharmacology, and toxicology. Moreover, they allow for the engineering of bioartificial tissue and are promising candidates for cellular therapies. For many of these applications, the ability to genetically modify pluripotent stem cells (PSCs) is indispensable, but efficient site-specific and safe technologies for genetic engineering of PSCs were developed only recently. By now, customized engineered nucleases provide excellent tools for targeted genome editing, opening new perspectives for biomedical research and cellular therapies. PMID:27347935

  9. Site Specific Analyses of a Spent Nuclear Fuel Transportation Accident

    SciTech Connect

    Biwer, B. M.; Chen, S. Y.

    2003-02-24

    The number of spent nuclear fuel (SNF) shipments is expected to increase significantly during the time period that the United States' inventory of SNF is sent to a final disposal site. Prior work estimated that the highest accident risks of a SNF shipping campaign to the proposed geologic repository at Yucca Mountain were in the corridor states, such as Illinois. The largest potential human health impacts would be expected to occur in areas with high population densities such as urban settings. Thus, our current study examined the human health impacts from the most plausible severe SNF transportation accidents in the Chicago metropolitan area. The RISKIND 2.0 program was used to model site-specific data for an area where the largest impacts might occur. The results have shown that the radiological human health consequences of a severe SNF rail transportation accident on average might be similar to one year of exposure to natural background radiation for those persons living a nd working in the most affected areas downwind of the actual accident location. For maximally exposed individuals, an exposure similar to about two years of exposure to natural background radiation was estimated. In addition to the accident probabilities being very low (approximately 1 chance in 10,000 or less during the entire shipping campaign), the actual human health impacts are expected to be lower if any of the accidents considered did occur, because the results are dependent on the specific location and weather conditions, such as wind speed and direction, that were selected to maximize the results. Also, comparison of the results of longer duration accident scenarios against U.S. Environmental Protection Agency guidelines was made to demonstrate the usefulness of this site-specific analysis for emergency planning purposes.

  10. Flow Shear Stress and Atherosclerosis: A Matter of Site Specificity

    PubMed Central

    Nigro, Patrizia; Abe, Jun-ichi

    2011-01-01

    Abstract It is well accepted that atherosclerosis occurs in a site-specific manner especially at branch points where disturbed blood flow (d-flow) predisposes to the development of plaques. Investigations both in vivo and in vitro have shown that d-flow is pro-atherogenic by promoting oxidative and inflammatory states in the artery wall. In contrast, steady laminar blood flow (s-flow) is atheroprotective by inhibition of oxidative stress and inflammation in the vessel wall. The mechanism for inflammation in endothelial cells (ECs) exposed to d-flow has been well studied and includes redox-dependent activation of apoptosis signal-regulating kinase 1 (ASK1) and Jun NH2-terminal kinase (JNK) that ultimately lead to the expression of adhesive molecules. In contrast, s-flow leads to the activation of the mitogen extracellular-signal-regulated kinase kinase 5/extracellular signal-regulated kinase-5 (MEK5/ERK5) pathway that prevents pro-inflammatory signaling. Important transcriptional events that reflect the pro-oxidant and pro-inflammatory condition of ECs in d-flow include the activation of activator protein 1 (AP-1) and nuclear factor kappaB (NFκB), whereas in s-flow, activation of Krüppel-like factor 2 (KLF2) and nuclear factor erythroid 2-like 2 (Nrf2) are dominant. Recent studies have shown that protein kinase c zeta (PKCζ) is highly activated under d-flow conditions and may represent a molecular switch for EC signaling and gene expression. The targeted modulation of proteins activated in a site-specific manner holds the promise for a new approach to limit atherosclerosis. Antioxid. Redox Signal. 15, 1405–1414. PMID:21050140

  11. The λ Integrase Site-specific Recombination Pathway.

    PubMed

    Landy, Arthur

    2015-04-01

    The site-specific recombinase encoded by bacteriophage λ (Int) is responsible for integrating and excising the viral chromosome into and out of the chromosome of its Escherichia coli host. Int carries out a reaction that is highly directional, tightly regulated, and depends upon an ensemble of accessory DNA bending proteins acting on 240 bp of DNA encoding 16 protein binding sites. This additional complexity enables two pathways, integrative and excisive recombination, whose opposite, and effectively irreversible, directions are dictated by different physiological and environmental signals. Int recombinase is a heterobivalent DNA binding protein and each of the four Int protomers, within a multiprotein 400 kDa recombinogenic complex, is thought to bind and, with the aid of DNA bending proteins, bridge one arm- and one core-type DNA site. In the 12 years since the publication of the last review focused solely on the λ site-specific recombination pathway in Mobile DNA II, there has been a great deal of progress in elucidating the molecular details of this pathway. The most dramatic advances in our understanding of the reaction have been in the area of X-ray crystallography where protein-DNA structures have now been determined for of all of the DNA-protein interfaces driving the Int pathway. Building on this foundation of structures, it has been possible to derive models for the assembly of components that determine the regulatory apparatus in the P-arm, and for the overall architectures that define excisive and integrative recombinogenic complexes. The most fundamental additional mechanistic insights derive from the application of hexapeptide inhibitors and single molecule kinetics. PMID:26104711

  12. Improving Site-Specific Radiological Performance Assessments - 13431

    SciTech Connect

    Tauxe, John; Black, Paul; Catlett, Kate; Lee, Robert; Perona, Ralph; Stockton, Tom; Sully, Mike

    2013-07-01

    An improved approach is presented for conducting complete and defensible radiological site-specific performance assessments (PAs) to support radioactive waste disposal decisions. The basic tenets of PA were initiated some thirty years ago, focusing on geologic disposals and evaluating compliance with regulations. Some of these regulations were inherently probabilistic (i.e., addressing uncertainty in a quantitative fashion), such as the containment requirements of the U.S. Environmental Protection Agency's (EPA's) 40 CFR 191, Environmental Radiation Protection Standards for Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes, Chap. 191.13 [1]. Methods of analysis were developed to meet those requirements, but at their core early PAs used 'conservative' parameter values and modeling approaches. This limited the utility of such PAs to compliance evaluation, and did little to inform decisions about optimizing disposal, closure and long-term monitoring and maintenance, or, in general, maintaining doses 'as low as reasonably achievable' (ALARA). This basic approach to PA development in the United States was employed essentially unchanged through the end of the 20. century, principally by the U.S. Department of Energy (DOE). Performance assessments developed in support of private radioactive waste disposal operations, regulated by the U.S. Nuclear Regulatory Commission (NRC) and its agreement states, were typically not as sophisticated. Discussion of new approaches to PA is timely, since at the time of this writing, the DOE is in the midst of revising its Order 435.1, Radioactive Waste Management [2], and the NRC is revising 10 CFR 61, Licensing Requirements for Land Disposal of Radioactive Waste [3]. Over the previous decade, theoretical developments and improved computational technology have provided the foundation for integrating decision analysis (DA) concepts and objective-focused thinking, plus a Bayesian approach to

  13. Viral induction of site-specific chromosome damage.

    PubMed

    Fortunato, Elizabeth A; Spector, Deborah H

    2003-01-01

    The advent of advanced cell culture and cytogenetics techniques in the 1950s opened a new avenue for research on the pathogenic interactions between animal viruses and their hosts. Studies of many viruses revealed their ability to nonspecifically induce cytogenetic damage to their host cell's chromosomes. However, only three viruses, the oncogenic adenoviruses, herpes simplex virus (HSV) and human cytomegalovirus (HCMV), have been found to cause non-random, site-specific chromosomal damage. Adenovirus (Ad) type 12 induces fragility at four distinct loci (RNU1, RNU2, RN5S and PSU1) in many different types of human cells. A common feature of these loci is that they contain a repeated array of transcriptionally active genes encoding small structural RNAs. Site-specific induction of breaks also requires the virally encoded E1B protein of M(r) 55000 and the C-terminus of the cellular p53 protein. Analysis of the induction of damage by HSV and HCMV necessitates consideration of several factors, including the strain of virus used, the timing of infection, the type of cell used, and the multiplicity of infection. Both HSV strains 1 and 2 are cytotoxic, although the former seems to be more proficient at inducing damage. At early times post infection, HSV induces breaks and specific uncoiling of the centromeres of chromosomes 1, 9 and 16. This is followed at later times by a more complete severing of all of the chromosomes, termed pulverisation. Damage by HSV requires viral entry and de novo viral protein synthesis, with immediate early viral proteins responsible for the induction of breaks and uncoiling and early gene products (most likely nucleases) involved in the extensive pulverisation seen later. HCMV has been studied primarily in permissive human fibroblasts. Its ability to induce specific damage in chromosome 1 at two loci, 1q21 and 1q42, was only recently revealed as the cells must be in S-phase when they are infected for the breaks to be observed. In contrast to

  14. Monomeric site-specific nucleases for genome editing

    PubMed Central

    Kleinstiver, Benjamin P.; Wolfs, Jason M.; Kolaczyk, Tomasz; Roberts, Alanna K.; Hu, Sherry X.; Edgell, David R.

    2012-01-01

    Targeted manipulation of complex genomes often requires the introduction of a double-strand break at defined locations by site-specific DNA endonucleases. Here, we describe a monomeric nuclease domain derived from GIY-YIG homing endonucleases for genome-editing applications. Fusion of the GIY-YIG nuclease domain to three-member zinc-finger DNA binding domains generated chimeric GIY-zinc finger endonucleases (GIY-ZFEs). Significantly, the I-TevI-derived fusions (Tev-ZFEs) function in vitro as monomers to introduce a double-strand break, and discriminate in vitro and in bacterial and yeast assays against substrates lacking a preferred 5′-CNNNG-3′ cleavage motif. The Tev-ZFEs function to induce recombination in a yeast-based assay with activity on par with a homodimeric Zif268 zinc-finger nuclease. We also fused the I-TevI nuclease domain to a catalytically inactive LADGLIDADG homing endonuclease (LHE) scaffold. The monomeric Tev-LHEs are active in vivo and similarly discriminate against substrates lacking the 5′-CNNNG-3′ motif. The monomeric Tev-ZFEs and Tev-LHEs are distinct from the FokI-derived zinc-finger nuclease and TAL effector nuclease platforms as the GIY-YIG domain alleviates the requirement to design two nuclease fusions to target a given sequence, highlighting the diversity of nuclease domains with distinctive biochemical properties suitable for genome-editing applications. PMID:22566637

  15. Analysis of Chemokine Receptor Trafficking by Site-Specific Biotinylation

    PubMed Central

    Liebick, Marcel; Schläger, Christian; Oppermann, Martin

    2016-01-01

    Chemokine receptors undergo internalization and desensitization in response to ligand activation. Internalized receptors are either preferentially directed towards recycling pathways (e.g. CCR5) or sorted for proteasomal degradation (e.g. CXCR4). Here we describe a method for the analysis of receptor internalization and recycling based on specific Bir A-mediated biotinylation of an acceptor peptide coupled to the receptor, which allows a more detailed analysis of receptor trafficking compared to classical antibody-based detection methods. Studies on constitutive internalization of the chemokine receptors CXCR4 (12.1% ± 0.99% receptor internalization/h) and CCR5 (13.7% ± 0.68%/h) reveals modulation of these processes by inverse (TAK779; 10.9% ± 0.95%/h) or partial agonists (Met-CCL5; 15.6% ± 0.5%/h). These results suggest an actively driven internalization process. We also demonstrate the advantages of specific biotinylation compared to classical antibody detection during agonist-induced receptor internalization, which may be used for immunofluorescence analysis as well. Site-specific biotinylation may be applicable to studies on trafficking of transmembrane proteins, in general. PMID:27310579

  16. Site-specific group selection drives locally adapted group compositions.

    PubMed

    Pruitt, Jonathan N; Goodnight, Charles J

    2014-10-16

    Group selection may be defined as selection caused by the differential extinction or proliferation of groups. The socially polymorphic spider Anelosimus studiosus exhibits a behavioural polymorphism in which females exhibit either a 'docile' or 'aggressive' behavioural phenotype. Natural colonies are composed of a mixture of related docile and aggressive individuals, and populations differ in colonies' characteristic docile:aggressive ratios. Using experimentally constructed colonies of known composition, here we demonstrate that population-level divergence in docile:aggressive ratios is driven by site-specific selection at the group level--certain ratios yield high survivorship at some sites but not others. Our data also indicate that colonies responded to the risk of extinction: perturbed colonies tended to adjust their composition over two generations to match the ratio characteristic of their native site, thus promoting their long-term survival in their natal habitat. However, colonies of displaced individuals continued to shift their compositions towards mixtures that would have promoted their survival had they remained at their home sites, regardless of their contemporary environment. Thus, the regulatory mechanisms that colonies use to adjust their composition appear to be locally adapted. Our data provide experimental evidence of group selection driving collective traits in wild populations. PMID:25274310

  17. Site-specific anticancer effects of dietary flavonoid quercetin.

    PubMed

    Sak, Katrin

    2014-01-01

    Food-derived flavonoid quercetin, widely distributed in onions, apples, and tea, is able to inhibit growth of various cancer cells indicating that this compound can be considered as a good candidate for anticancer therapy. Although the exact mechanism of this action is not thoroughly understood, behaving as antioxidant and/or prooxidant as well as modulating different intracellular signalling cascades may all play a certain role. Such inhibitory activity of quercetin has been shown to depend first of all on cell lines and cancer types; however, no comprehensive site-specific analysis of this effect has been published. In this review article, cytotoxicity constants of quercetin measured in various human malignant cell lines of different origin were compiled from literature and a clear cancer selective action was demonstrated. The most sensitive malignant sites for quercetin revealed to be cancers of blood, brain, lung, uterine, and salivary gland as well as melanoma whereas cytotoxic activity was higher in more aggressive cells compared to the slowly growing cells showing that the most harmful cells for the organism are probably targeted. More research is needed to overcome the issues of poor water solubility and relatively low bioavailability of quercetin as the major obstacles limiting its clinical use. PMID:24377461

  18. Site Specific Cleavage Mediated by MMPs Regulates Function of Agrin

    PubMed Central

    McFarlane, Ainsley; Xie, Irene; Overall, Christopher M.; Stetefeld, Jörg

    2012-01-01

    Background Agrin is the key inducer of postsynaptic differentiations at the neuromuscular junction. The multidomain heparan sulfate proteoglycan is mediating via its N-terminal segment the interaction with laminin, whereas the C-terminal portion is responsible for Dystroglycan binding and clustering of the Acetylcholine receptor. Matrix metalloproteinases (MMP) are known to play essential roles in matrix remodeling, degradation and regulation of extracellular signaling networks. Principal Findings Site-specific processing of Agrin provides key insight into regulatory effects of Matrix metalloproteinases (MMPs). Here, we present a detailed study of agrin processing by different MMPs together with a molecular understanding of binding and cleavage at both terminal fragments. The data suggest for a regulatory effect of MMP cleavage at particularly important functional sites of agrin. Cleave of agrin abolishes the agrin-laminin complex formation and the Acetylcholine receptor clustering at the neuromuscular junction. Conclusion/Significance Agrin is a target of specific MMP processing resulting in agrin subfragments with different regulatory activities. MMP processing is a powerful tool to regulate extracellular signaling networks. PMID:22984437

  19. Bone site-specific delivery of siRNA

    PubMed Central

    Liu, Xinli

    2016-01-01

    Abstract Small interfering RNAs (siRNA) have enormous potential as therapeutics to target and treat various bone disorders such as osteoporosis and cancer bone metastases. However, effective and specific delivery of siRNA therapeutics to bone and bone-specific cells in vivo is very challenging. To realize the full therapeutic potential of siRNA in treating bone disorders, a safe and efficient, tissue- and cell-specific delivery system must be developed. This review focuses on recent advances in bone site-specific delivery of siRNA at the tissue or cellular level. Bone-targeted nanoparticulate siRNA carriers and various bone-targeted moieties such as bisphosphonates, oligopeptides (Asp)8 and (AspSerSer)6, and aptamers are highlighted. Incorporation of these bone-seeking targeting moieties into siRNA carriers allows for recognition of different sub-tissue functional domains of bone and also specific cell types residing in bone tissue. It also provides a means for bone-formation surface-, bone-resorption surface-, or osteoblast-specific targeting and transportation of siRNA therapeutics. The discussion mainly focuses on systemic and local bone-specific delivery of siRNA in osteoporosis and bone metastasis preclinical models. PMID:26642236

  20. Site-specific PEGylation of lidamycin and its antitumor activity.

    PubMed

    Li, Liang; Shang, Boyang; Hu, Lei; Shao, Rongguang; Zhen, Yongsu

    2015-05-01

    In this study, N-terminal site-specific mono-PEGylation of the recombinant lidamycin apoprotein (rLDP) of lidamycin (LDM) was prepared using a polyethyleneglycol (PEG) derivative (M w 20 kDa) through a reactive terminal aldehyde group under weak acidic conditions (pH 5.5). The biochemical properties of mPEG-rLDP-AE, an enediyne-integrated conjugate, were analyzed by SDS-PAGE, RP-HPLC, SEC-HPLC and MALDI-TOF. Meanwhile, in vitro and in vivo antitumor activity of mPEG-rLDP-AE was evaluated by MTT assays and in xenograft model. The results indicated that mPEG-rLDP-AE showed significant antitumor activity both in vitro and in vivo. After PEGylation, mPEG-rLDP still retained the binding capability to the enediyne AE and presented the physicochemical characteristics similar to that of native LDP. It is of interest that the PEGylation did not diminish the antitumor efficacy of LDM, implying the possibility that this derivative may function as a payload to deliver novel tumor-targeted drugs. PMID:26579455

  1. Micro-tattoo guided OCT imaging of site specific inflammation

    NASA Astrophysics Data System (ADS)

    Phillips, Kevin G.; Choudhury, Niloy; Samatham, Ravikant V.; Singh, Harvinder; Jacques, Steven L.

    2010-02-01

    Epithelial biologists studying human skin diseases such as cancer formation and psoriasis commonly utilize mouse models to characterize the interplay among cells and intracellular signal transduction pathways that result in programmed changes in gene expression and cellular behaviors. The information obtained from animal models is useful only when phenotypic presentations of disease recapitulate those observed in humans. Excision of tissues followed by histochemical analysis is currently the primary means of establishing the morphological presentation. Non invasive imaging of animal models provides an alternate means to characterize tissue morphology associated with the disease of interest in vivo. While useful, the ability to perform in vivo imaging at different time points in the same tissue location has been a challenge. This information is key to understanding site specific changes as the imaged tissue can now be extracted and analyzed for mRNA expression. We present a method employing a micro-tattoo to guide optical coherence tomography (OCT) imaging of ultraviolet induced inflammation over time in the same tissue locations.

  2. Site-specific basal body duplication in Chlamydomonas.

    PubMed

    O'Toole, Eileen T; Dutcher, Susan K

    2014-02-01

    Correct centriole/basal body positioning is required for numerous biological processes, yet how the cell establishes this positioning is poorly understood. Analysis of centriolar/basal body duplication provides a key to understanding basal body positioning and function. Chlamydomonas basal bodies contain structural features that enable specific triplet microtubules to be specified. Electron tomography of cultures enriched in mitotic cells allowed us to follow basal body duplication and identify a specific triplet at which duplication occurs. Probasal bodies elongate in prophase, assemble transitional fibers (TF) and are segregated with a mature basal body near the poles of the mitotic spindle. A ring of nine-singlet microtubules is initiated at metaphase, orthogonal to triplet eight. At telophase/cytokinesis, triplet microtubule blades assemble first at the distal end, rather than at the proximal cartwheel. The cartwheel undergoes significant changes in length during duplication, which provides further support for its scaffolding role. The uni1-1 mutant contains short basal bodies with reduced or absent TF and defective transition zones, suggesting that the UNI1 gene product is important for coordinated probasal body elongation and maturation. We suggest that this site-specific basal body duplication ensures the correct positioning of the basal body to generate landmarks for intracellular patterning in the next generation. PMID:24166861

  3. CuFe2O4 magnetic nanocrystal clusters as a matrix for the analysis of small molecules by negative-ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    PubMed

    Lin, Zian; Zheng, Jiangnan; Bian, Wei; Cai, Zongwei

    2015-08-01

    CuFe2O4 magnetic nanocrystal clusters (CuFe2O4 MNCs) were proposed as a new matrix for small molecule analysis by negative ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the first time. We demonstrated its advantages over conventional organic matrices in the detection of small molecules such as amino acids, peptides, nucleobases, fatty acids, and steroid hormones. A systematic comparison of CuFe2O4 MNCs with different ionization modes revealed that MS spectra obtained for the CuFe2O4 MNC matrix in the negative ion mode was only featured by deprotonated ion peaks with a free matrix background, which was different from the complicated alkali metal adducts produced in the positive ion mode. The developed method was found relatively tolerant to salt contamination and exhibited good reproducibility. A detection limit down to the subpicomolar level was achieved when testosterone was analyzed. In addition, by comparison of the MS spectra obtained from bare Fe3O4 and MFe2O4 MNC (M = Co, Ni, Cu, Zn) matrices, two main factors of MFe2O4 MNC matrices were revealed to play a vital role in assisting the negative ion desorption/ionization (D/I) process: doping transition metals into ferrite nanocrystals favoring laser absorption and energy transfer and a good match between the UV absorption of MFe2O4 MNCs and the excitation of nitrogen laser source facilitating LDI efficiency. This work creates a new branch of application for MFe2O4 MNCs and provides an alternative solution for small molecule analysis. PMID:26086699

  4. Site-Specific Seismic Site Response Model for the Waste Treatment Plant, Hanford, Washington

    SciTech Connect

    Rohay, Alan C.; Reidel, Steve P.

    2005-02-24

    This interim report documents the collection of site-specific geologic and geophysical data characterizing the Waste Treatment Plant site and the modeling of the site-specific structure response to earthquake ground motions.

  5. 75 FR 56526 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-16

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION... Environmental Management Site-Specific Advisory Board (EM SSAB), Portsmouth. The Federal Advisory Committee Act... areas of environmental restoration, waste management and related activities. Tentative Agenda...

  6. Site-specific hydrogen diffusion rates during clinopyroxene dehydration

    NASA Astrophysics Data System (ADS)

    Ferriss, Elizabeth; Plank, Terry; Walker, David

    2016-06-01

    The rate of hydrogen diffusion in clinopyroxene is relevant to interpreting hydrogen ("water") concentrations in xenoliths, phenocrysts, and clinopyroxene-hosted melt inclusions to provide insight into the deep-earth water cycle and volcanic explosivity. Here, we determine bulk and site-specific hydrogen diffusivities in two diopsides and an augite by heating initially homogeneous water-bearing samples in a 1-atm CO/CO2 gas-mixing furnace at 800-1000 °C and oxygen fugacity at the quartz-fayalite-magnetite buffer and observing H-loss profiles. The O-H stretching range between wavenumbers 3000 and 4000 cm-1 in FTIR spectra is resolved into 4-6 peaks, each of which is assumed to represent a distinct defect site for the hydrogen, to determine peak-specific diffusivities using our previously published whole-block method. For the diopside from the Kunlun Mts. in China, Arrhenius relations are reported for peaks at 3645, 3617, 3540, 3443, and 3355 cm-1 based on measurements at 816, 904, and 1000 °C. Bulk and site-specific diffusivities are determined for the same set of peaks at 904 °C for the second diopside (Jaipur). The augite (PMR-53) was a triangular thin slab, and hydrogen diffusivities were determined for bulk hydrogen and peaks at 3620, 3550, 3460, and 3355 cm-1 in the thickness direction at 800 °C. Bulk hydrogen diffusivity in the Jaipur diopside is consistent with previous work, and hydrogen diffusivity in augite PMR-53 is slightly lower than the fast direction diffusivities measured || [100] and [001]* in Jaipur diopside. Both diopsides show 1-2 orders of magnitude differences in the peaks-specific diffusivities, with the fastest diffusivities at 3450 cm-1 and the slowest at 3645 cm-1. However, the hydrogen diffusivities in Jaipur diopside are 2-4 orders of magnitude higher than those in Kunlun diopside for bulk hydrogen and all peaks. Thus, peak-specific differences cannot by themselves adequately explain the 5 orders of magnitude range in hydrogen

  7. Oxygen as a site specific structural probe in neutron diffraction

    SciTech Connect

    Neuefeind, Joerg C; Simonson, J Michael {Mike}; Salmon, Phil; Zeidler, Anita; Fischer, Henry E; Rauch, Helmut; Markland, Thomas; Lemmel, Hartmut

    2011-01-01

    Oxygen is a ubiquitous element, playing an essential role in most scientific and technological disciplines, and is often incorporated within a structurally disordered material where examples include molten silicates in planetary science, glasses used for lasers and optical communication, and water in biological processes. Establishing the structure of a liquid or glassy oxide and thereby its relation to the functional properties of a material is not, however, a trivial task owing to the complexity associated with atomic disorder. Here we approach this challenge by measuring the bound coherent neutron scattering lengths of the oxygen isotopes with the sensitive technique of neutron interferometry. We find that there is a small but finite contrast of 0.204(6) fm between the scattering lengths of the isotope 18O and oxygen of natural isotopic abundance natO, contrary to tables of recommended values. This has enabled us to investigate the structure of both light and heavy water by exploiting, for the first time, the method of oxygen isotope substitution in neutron diffraction, thus circumventing many of the significant problems associated with more traditional methods in which hydrogen is substituted by deuterium. We find a difference of ~0.5% between the O-H and O-D intra-molecular bond distances which is much smaller than recent estimates based on diffraction data and is found to be in excellent agreement with path integral molecular dynamics simulations made with a flexible polarisable water model. Our results demonstrate the potential for using oxygen isotope substitution as a powerful and effective site specific probe in a plethora of materials, of pertinence as instrumentation at next generation neutron sources comes online

  8. Effect of site-specific modification on restriction endonucleases and DNA modification methyltransferases.

    PubMed Central

    McClelland, M; Nelson, M; Raschke, E

    1994-01-01

    Restriction endonucleases have site-specific interactions with DNA that can often be inhibited by site-specific DNA methylation and other site-specific DNA modifications. However, such inhibition cannot generally be predicted. The empirically acquired data on these effects are tabulated for over 320 restriction endonucleases. In addition, a table of known site-specific DNA modification methyltransferases and their specificities is presented along with EMBL database accession numbers for cloned genes. PMID:7937074

  9. Hetero-site-specific X-ray pump-probe spectroscopy for femtosecond intramolecular dynamics.

    PubMed

    Picón, A; Lehmann, C S; Bostedt, C; Rudenko, A; Marinelli, A; Osipov, T; Rolles, D; Berrah, N; Bomme, C; Bucher, M; Doumy, G; Erk, B; Ferguson, K R; Gorkhover, T; Ho, P J; Kanter, E P; Krässig, B; Krzywinski, J; Lutman, A A; March, A M; Moonshiram, D; Ray, D; Young, L; Pratt, S T; Southworth, S H

    2016-01-01

    New capabilities at X-ray free-electron laser facilities allow the generation of two-colour femtosecond X-ray pulses, opening the possibility of performing ultrafast studies of X-ray-induced phenomena. Particularly, the experimental realization of hetero-site-specific X-ray-pump/X-ray-probe spectroscopy is of special interest, in which an X-ray pump pulse is absorbed at one site within a molecule and an X-ray probe pulse follows the X-ray-induced dynamics at another site within the same molecule. Here we show experimental evidence of a hetero-site pump-probe signal. By using two-colour 10-fs X-ray pulses, we are able to observe the femtosecond time dependence for the formation of F ions during the fragmentation of XeF2 molecules following X-ray absorption at the Xe site. PMID:27212390

  10. Hetero-site-specific X-ray pump-probe spectroscopy for femtosecond intramolecular dynamics

    NASA Astrophysics Data System (ADS)

    Picón, A.; Lehmann, C. S.; Bostedt, C.; Rudenko, A.; Marinelli, A.; Osipov, T.; Rolles, D.; Berrah, N.; Bomme, C.; Bucher, M.; Doumy, G.; Erk, B.; Ferguson, K. R.; Gorkhover, T.; Ho, P. J.; Kanter, E. P.; Krässig, B.; Krzywinski, J.; Lutman, A. A.; March, A. M.; Moonshiram, D.; Ray, D.; Young, L.; Pratt, S. T.; Southworth, S. H.

    2016-05-01

    New capabilities at X-ray free-electron laser facilities allow the generation of two-colour femtosecond X-ray pulses, opening the possibility of performing ultrafast studies of X-ray-induced phenomena. Particularly, the experimental realization of hetero-site-specific X-ray-pump/X-ray-probe spectroscopy is of special interest, in which an X-ray pump pulse is absorbed at one site within a molecule and an X-ray probe pulse follows the X-ray-induced dynamics at another site within the same molecule. Here we show experimental evidence of a hetero-site pump-probe signal. By using two-colour 10-fs X-ray pulses, we are able to observe the femtosecond time dependence for the formation of F ions during the fragmentation of XeF2 molecules following X-ray absorption at the Xe site.

  11. Hetero-site-specific X-ray pump-probe spectroscopy for femtosecond intramolecular dynamics

    PubMed Central

    Picón, A.; Lehmann, C. S.; Bostedt, C.; Rudenko, A.; Marinelli, A.; Osipov, T.; Rolles, D.; Berrah, N.; Bomme, C.; Bucher, M.; Doumy, G.; Erk, B.; Ferguson, K. R.; Gorkhover, T.; Ho, P. J.; Kanter, E. P.; Krässig, B.; Krzywinski, J.; Lutman, A. A.; March, A. M.; Moonshiram, D.; Ray, D.; Young, L.; Pratt, S. T.; Southworth, S. H.

    2016-01-01

    New capabilities at X-ray free-electron laser facilities allow the generation of two-colour femtosecond X-ray pulses, opening the possibility of performing ultrafast studies of X-ray-induced phenomena. Particularly, the experimental realization of hetero-site-specific X-ray-pump/X-ray-probe spectroscopy is of special interest, in which an X-ray pump pulse is absorbed at one site within a molecule and an X-ray probe pulse follows the X-ray-induced dynamics at another site within the same molecule. Here we show experimental evidence of a hetero-site pump-probe signal. By using two-colour 10-fs X-ray pulses, we are able to observe the femtosecond time dependence for the formation of F ions during the fragmentation of XeF2 molecules following X-ray absorption at the Xe site. PMID:27212390

  12. THERMAL DESORPTION TREATMENT

    EPA Science Inventory

    Thermal desorption is an ex situ means to physically separate volatile and some semivolatile contaminants from soil, sediments, sludges, and filter cakes. or wastes containing up to 10% organics or less, thermal desorption can be used alone for site remediation. t also may find a...

  13. Light-stimulated cargo release from a core–shell structured nanocomposite for site-specific delivery

    SciTech Connect

    Cai, Yun; Ling, Li; Li, Xiaofang; Chen, Meng; Su, Likai

    2015-03-15

    This paper reported a core–shell structured site-specific delivery system with a light switch triggered by low energy light (λ=510 nm). Its core was composed of supermagnetic Fe{sub 3}O{sub 4} nanoparticles for magnetic guiding and targeting. Its outer shell consisted of mesoporous silica molecular sieve MCM-41 which offered highly ordered hexagonal tunnels for cargo capacity. A light switch N1-(4aH-cyclopenta[1,2-b:5,4-b′]dipyridin-5(5aH)-ylidene)benzene-1, 4-diamine (CBD) was covalently grafted into these hexagonal tunnels, serving as light stimuli acceptor with loading content of 1.1 μM/g. This composite was fully characterized and confirmed by SEM, TEM, XRD patterns, N{sub 2} adsorption/desorption, thermogravimetric analysis, IR, UV–vis absorption and emission spectra. Experimental data suggested that this composite had a core as wide as 150 nm and could be magnetically guided to specific sites. Its hexagonal tunnels were as long as 180 nm. Upon light stimuli of “on” and “off” states, controllable release was observed with short release time of ~900 s (90% capacity). - Graphical abstract: A core–shell structured site-specific delivery system with a light switch triggered by yellow light was constructed. Controllable release was observed with short release time of ~900 s (90% capacity). - Highlights: • A core–shell structured site-specific delivery system was constructed. • It consisted of Fe{sub 3}O{sub 4} core and MCM-41 shell grafted with light switch. • This delivery system was triggered by low energy light. • Controllable release was observed with short release time of ~900 s.

  14. Dopant-Assisted Positive Photoionization Ion Mobility Spectrometry Coupled with Time-Resolved Thermal Desorption for On-Site Detection of Triacetone Triperoxide and Hexamethylene Trioxide Diamine in Complex Matrices.

    PubMed

    Jiang, Dandan; Peng, Liying; Wen, Meng; Zhou, Qinghua; Chen, Chuang; Wang, Xin; Chen, Wendong; Li, Haiyang

    2016-04-19

    Peroxide explosives, such as triacetone triperoxide (TATP) and hexamethylene trioxide diamine (HMTD), were often used in the terrorist attacks due to their easy synthesis from readily starting materials. Therefore, an on-site detection method for TATP and HMTD is urgently needed. Herein, we developed a stand-alone dopant-assisted positive photoionization ion mobility spectrometry (DAPP-IMS) coupled with time-resolved thermal desorption introduction for rapid and sensitive detection of TATP and HMTD in complex matrices, such as white solids, soft drinks, and cosmetics. Acetone was chosen as the optimal dopant for better separation between reactant ion peaks and product ion peaks as well as higher sensitivity, and the limits of detection (LODs) of TATP and HMTD standard samples were 23.3 and 0.2 ng, respectively. Explosives on the sampling swab were thermally desorbed and carried into the ionization region dynamically within 10 s, and the maximum released concentration of TATP or HMTD could be time-resolved from the matrix interference owing to the different volatility. Furthermore, with the combination of the fast response thermal desorber (within 0.8 s) and the quick data acquisition software to DAPP-IMS, two-dimensional data related to drift time (TATP: 6.98 ms, K0 = 2.05 cm(2) V(-1) s(-1); HMTD: 9.36 ms, K0 = 1.53 cm(2) V(-1) s(-1)) and desorption time was obtained for TATP and HMTD, which is beneficial for their identification in complex matrices. PMID:27031877

  15. Ultraviolet laser desorption/ionization mass spectrometry of single-core and multi-core polyaromatic hydrocarbons under variable conditions of collisional cooling: insights into the generation of molecular ions, fragments and oligomers.

    PubMed

    Gámez, Francisco; Hortal, Ana R; Martínez-Haya, Bruno; Soltwisch, Jens; Dreisewerd, Klaus

    2014-11-01

    The ultraviolet laser desorption/ionization of polyaromatic hydrocarbons (PAHs) has been investigated under different background pressures of an inert gas (up to 1.2 mbar of N2) in the ion source of a hybrid, orthogonal-extracting time-of-flight mass spectrometer (oTOF-MS). The study includes an ensemble of six model PAHs with isolated single polyaromatic cores and four ones with multiple cross-linked aromatic and polyaromatic cores. In combination with a weak ion extraction field, the variation of the buffer gas pressure allowed to control the degree of collisional cooling of the desorbed PAHs and, thus, to modulate their decomposition into fragments. The dominant fragmentation channels observed are related to dehydrogenation of the PAHs, in most cases through the cleavage of even numbers of C-H bonds. Breakage of C-C bonds leading to the fragmentation of rings, side chains and core linkages is also observed, in particular, at low buffer gas pressures. The precise patterns of the combined fragmentation processes vary significantly between the PAHs. The highest abundances of molecular PAH ions and cleanest mass spectra were consistently obtained at the highest buffer gas pressure of 1.2 mbar. The effective quenching of the fragmentation pathways at this elevated pressure improves the sensitivity and data interpretation for analytical applications, although the fragmentation of side chains and of bonds between (poly)aromatic cores is not completely suppressed in all cases. Moreover, these results suggest that the detected fragments are generated through thermal equilibrium processes rather than as a result of rapid photolysis. This assumption is further corroborated by a laser desorption/ionization post-source decay analysis using an axial time-of-flight MS. In line with these findings, covalent oligomers of the PAHs, which are presumably formed by association of two or more dehydrogenated fragments, are detected with higher abundances at the lower buffer gas

  16. Field desorption of Na and Cs from graphene on iridium

    NASA Astrophysics Data System (ADS)

    Bernatskii, D. P.; Pavlov, V. G.

    2015-08-01

    Field electron and desorption microscopy has been used to study specific features of the field desorption of sodium and cesium ions adsorbed on the surface of iridium with graphene. It was found that adsorbed sodium atoms most strongly reduce the work function on graphene islands situated over densely packed faces of iridium. A strong electric field qualitatively similarly affects the sodium and cesium desorption processes from a field emitter to give two desorption phases and has no noticeable effect on the disintegration of the graphene layer.

  17. Source-Identifying Biomarker Ions between Environmental and Clinical Burkholderia pseudomallei Using Whole-Cell Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS)

    PubMed Central

    Srisanga, Kitima; Roytrakul, Sittiruk; Tungpradabkul, Sumalee

    2014-01-01

    Burkholderia pseudomallei is the causative agent of melioidosis, which is an endemic disease in Northeast Thailand and Northern Australia. Environmental reservoirs, including wet soils and muddy water, serve as the major sources for contributing bacterial infection to both humans and animals. The whole-cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (whole-cell MALDI-TOF MS) has recently been applied as a rapid, accurate, and high-throughput tool for clinical diagnosis and microbiological research. In this present study, we employed a whole-cell MALDI-TOF MS approach for assessing its potency in clustering a total of 11 different B. pseudomallei isolates (consisting of 5 environmental and 6 clinical isolates) with respect to their origins and to further investigate the source-identifying biomarker ions belonging to each bacterial group. The cluster analysis demonstrated that six out of eleven isolates were grouped correctly to their sources. Our results revealed a total of ten source-identifying biomarker ions, which exhibited statistically significant differences in peak intensity between average environmental and clinical mass spectra using ClinProTools software. Six out of ten mass ions were assigned as environmental-identifying biomarker ions (EIBIs), including, m/z 4,056, 4,214, 5,814, 7,545, 7,895, and 8,112, whereas the remaining four mass ions were defined as clinical-identifying biomarker ions (CIBIs) consisting of m/z 3,658, 6,322, 7,035, and 7,984. Hence, our findings represented, for the first time, the source-specific biomarkers of environmental and clinical B. pseudomallei. PMID:24914956

  18. Characterization by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry of the major photoproducts of temoporfin (m-THPC) and bacteriochlorin (m-THPBC).

    PubMed

    Angotti, M; Maunit, B; Muller, J F; Bezdetnaya, L; Guillemin, F

    2001-07-01

    The photobleaching of 5,10,15,20-tetrakis(m-hydroxyphenyl)chlorin (temoporfin, m-THPC) and 5,10,15,20-tetrakis(m-hydroxyphenyl)bacteriochlorin (bacteriochlorin, m-THPBC) was studied in ethanol-water (1 : 99, v/v) and in physiological medium (phosphate-buffered saline, PBS) with or without fetal calf serum (FCS). m-THPC solution was irradiated with the laser radiation of 650 nm, whereas m-THPBC solution underwent two consecutive irradiations at 532 and 650 nm. The photoproducts were characterized by UV-visible absorption spectrophotometry and by matrix-assisted laser desorption/ionization (MALDI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). Independent of the solvent used, the phototransformation of either photosensitizer yielded the formation of 5,10,15,20-tetrakis (m-hydroxyphenyl)porphyrin (m-THPP) through a major dehydrogenation process. PMID:11473406

  19. BEAM PIPE DESORPTION RATE IN RHIC.

    SciTech Connect

    HUANG, H.; FISCHER, W.; HE, P.; HSEUH, H.C.; IRISO, U.; PTITSYN, V.; TRBOJEVIC, D.; WEI, J.; YANG, S.Y.

    2006-06-23

    In the past, an increase of beam intensity in RHIC has caused several decades of pressure rises in the warm sections during operation. This has been a major factor limiting the RHIC luminosity. About 430 meters of NEG coated beam pipes have been installed in the warm sections to ameliorate this problem. Beam ion induced desorption is one possible cause of pressure rises. A series beam studies in RHIC has been dedicated to estimate the desorption rate of various beam pipes (regular and NEG coated) at various warm sections. Correctors were used to generate local beam losses and consequently local pressure rises. The experimental results are presented and analyzed in this paper.

  20. STATIC AND KINETIC SITE-SPECIFIC PROTEIN-DNA PHOTOCROSSLINKING: ANALYSIS OF BACTERIAL TRANSCRIPTION INITIATION COMPLEXES

    PubMed Central

    Naryshkin, Nikolai; Druzhinin, Sergei; Revyakin, Andrei; Kim, Younggyu; Mekler, Vladimir; Ebright, Richard H.

    2009-01-01

    Static site-specific protein-DNA photocrosslinking permits identification of protein-DNA interactions within multiprotein-DNA complexes. Kinetic site-specific protein-DNA photocrosslinking--involving rapid-quench-flow mixing and pulsed-laser irradiation--permits elucidation of pathways and kinetics of formation of protein-DNA interactions within multiprotein-DNA complexes. We present detailed protocols for application of static and kinetic site-specific protein-DNA photocrosslinking to bacterial transcription initiation complexes. PMID:19378179

  1. Stable isotope, site-specific mass tagging for protein identification

    DOEpatents

    Chen, Xian

    2006-10-24

    Proteolytic peptide mass mapping as measured by mass spectrometry provides an important method for the identification of proteins, which are usually identified by matching the measured and calculated m/z values of the proteolytic peptides. A unique identification is, however, heavily dependent upon the mass accuracy and sequence coverage of the fragment ions generated by peptide ionization. The present invention describes a method for increasing the specificity, accuracy and efficiency of the assignments of particular proteolytic peptides and consequent protein identification, by the incorporation of selected amino acid residue(s) enriched with stable isotope(s) into the protein sequence without the need for ultrahigh instrumental accuracy. Selected amino acid(s) are labeled with .sup.13C/.sup.15N/.sup.2H and incorporated into proteins in a sequence-specific manner during cell culturing. Each of these labeled amino acids carries a defined mass change encoded in its monoisotopic distribution pattern. Through their characteristic patterns, the peptides with mass tag(s) can then be readily distinguished from other peptides in mass spectra. The present method of identifying unique proteins can also be extended to protein complexes and will significantly increase data search specificity, efficiency and accuracy for protein identifications.

  2. Tracing Site-Specific Reactions at Mineral/Fluid Interfaces

    NASA Astrophysics Data System (ADS)

    Boily, Jean-François

    2016-04-01

    Mineral surfaces are reactive transformation centres and sinks for gases, solutes and solvents. Under environmental conditions these surfaces are populated by (hydr)oxo functional groups that can undergo protonation, ligand exchange, and form intricate networks of hydrogen bonds. Knowledge of the types, distributions and orientations of these groups is essential for understanding molecular-scale processes taking place at mineral surfaces. This work is focused on the properties of hydroxo groups on important crystallographic planes of synthetic nano-sized iron and aluminum (oxyhydr)oxides exposed to vacuum, water vapor and/or carbon dioxide. Vibration spectroscopic signatures of hydroxo groups on these minerals will be presented alongside predictions from molecular dynamics simulations. This body of work forms the basis for a molecular-scale understanding of reactions taking place at surfaces of geochemically relevant mineral particles. These reactions are not only limited to ion and solvent exchange but are also extended to understand particle-particle interactions in the context of oriented aggregation.

  3. On-Chip Solid-Phase Extraction Preconcentration/Focusing Substrates Coupled to Atmospheric Pressure Matrix-Assisted Laser Desorption/Ionization Ion Trap Mass Spectrometry for High Sensitivity Biomolecule Analysis

    PubMed Central

    Navare, Arti; Nouzova, Marcela; Noriega, Fernando G.; Hernández-Martínez, Salvador; Menzel, Christoph; Fernández, Facundo M.

    2009-01-01

    Atmospheric pressure matrix-assisted laser desorption/ionization (AP-MALDI) has proven a convenient and rapid method for ion production in the mass spectrometric analysis of biomolecules. AP-MALDI and electrospray ion sources are easily interchangeable in most mass spectrometers. However, AP-MALDI suffers from less-than-optimal sensitivity due to ion losses during transport from the atmosphere into the vacuum of the mass spectrometer. Here, we study the signal-to-noise (S/N) ratio gains observed when an on-chip dynamic preconcentration/focusing approach is coupled to AP-MALDI for the MS analysis of neuropeptides and protein digests. It was found that, in comparison with conventional AP-MALDI targets, focusing targets showed (1) a sensitivity enhancement of approximately two orders of magnitude with S/N gains of 200–900 for hydrophobic substrates, and 150–400 for weak cation exchange (WCX) substrates; (2) improved detection limits as low as 5 fmol/μL for standard peptides; (3) significantly reduced matrix background; and (4) higher inter-day reproducibility. The improved sensitivity allowed successful tandem MS sequencing of dilute solutions of a derivatized tryptic digest of a protein standard, and enabled the first reported AP-MALDI MS detection of neuropeptides from Aedes aegypti mosquito heads. PMID:19140128

  4. Generalized theory on the mechanism of site-specific DNA–protein interactions

    NASA Astrophysics Data System (ADS)

    Niranjani, G.; Murugan, R.

    2016-05-01

    We develop a generalized theoretical framework on the binding of transcription factor proteins (TFs) with specific sites on DNA that takes into account the interplay of various factors regarding overall electrostatic potential at the DNA–protein interface, occurrence of kinetic traps along the DNA sequence, presence of other roadblock protein molecules along DNA and crowded environment, conformational fluctuations in the DNA binding domains (DBDs) of TFs, and the conformational state of the DNA. Starting from a Smolochowski type theoretical framework on site-specific binding of TFs we logically build our model by adding the effects of these factors one by one. Our generalized two-step model suggests that the electrostatic attractive forces present inbetween the positively charged DBDs of TFs and the negatively charged phosphate backbone of DNA, along with the counteracting shielding effects of solvent ions, is the core factor that creates a fluidic type environment at the DNA–protein interface. This in turn facilitates various one-dimensional diffusion (1Dd) processes such as sliding, hopping and intersegmental transfers. These facilitating processes as well as flipping dynamics of conformational states of DBDs of TFs between stationary and mobile states can enhance the 1Dd coefficient on a par with three-dimensional diffusion (3Dd). The random coil conformation of DNA also plays critical roles in enhancing the site-specific association rate. The extent of enhancement over the 3Dd controlled rate seems to be directly proportional to the maximum possible 1Dd length. We show that the overall site-specific binding rate scales with the length of DNA in an asymptotic way. For relaxed DNA, the specific binding rate will be independent of the length of DNA as length increases towards infinity. For condensed DNA as in in vivo conditions, the specific binding rate depends on the length of DNA in a turnover way with a maximum. This maximum rate seems to scale with the

  5. Site-specific O-Glycosylation Analysis of Human Blood Plasma Proteins*

    PubMed Central

    Hoffmann, Marcus; Marx, Kristina; Reichl, Udo; Wuhrer, Manfred; Rapp, Erdmann

    2016-01-01

    Site-specific glycosylation analysis is key to investigate structure-function relationships of glycoproteins, e.g. in the context of antigenicity and disease progression. The analysis, though, is quite challenging and time consuming, in particular for O-glycosylated proteins. In consequence, despite their clinical and biopharmaceutical importance, many human blood plasma glycoproteins have not been characterized comprehensively with respect to their O-glycosylation. Here, we report on the site-specific O-glycosylation analysis of human blood plasma glycoproteins. To this end pooled human blood plasma of healthy donors was proteolytically digested using a broad-specific enzyme (Proteinase K), followed by a precipitation step, as well as a glycopeptide enrichment and fractionation step via hydrophilic interaction liquid chromatography, the latter being optimized for intact O-glycopeptides carrying short mucin-type core-1 and -2 O-glycans, which represent the vast majority of O-glycans on human blood plasma proteins. Enriched O-glycopeptide fractions were subjected to mass spectrometric analysis using reversed-phase liquid chromatography coupled online to an ion trap mass spectrometer operated in positive-ion mode. Peptide identity and glycan composition were derived from low-energy collision-induced dissociation fragment spectra acquired in multistage mode. To pinpoint the O-glycosylation sites glycopeptides were fragmented using electron transfer dissociation. Spectra were annotated by database searches as well as manually. Overall, 31 O-glycosylation sites and regions belonging to 22 proteins were identified, the majority being acute-phase proteins. Strikingly, also 11 novel O-glycosylation sites and regions were identified. In total 23 O-glycosylation sites could be pinpointed. Interestingly, the use of Proteinase K proved to be particularly beneficial in this context. The identified O-glycan compositions most probably correspond to mono- and disialylated core-1

  6. 75 FR 6370 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-09

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific...: Wednesday, March 10, 2010, 5 p.m. ADDRESSES: Centennial Hills Library, 6711 North Buffalo Drive, Las...

  7. 77 FR 45345 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-31

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  8. 78 FR 3890 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-17

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  9. 76 FR 4644 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-26

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  10. 77 FR 23470 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-19

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  11. 77 FR 9219 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-16

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of Energy,...

  12. 76 FR 78908 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-20

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  13. 76 FR 65190 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-20

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  14. 76 FR 9572 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-18

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  15. 77 FR 29996 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-21

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  16. 76 FR 17637 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-30

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  17. 75 FR 24685 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  18. 75 FR 57462 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-21

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  19. 78 FR 63171 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ... Management Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation; Meeting AGENCY: Department...

  20. 76 FR 52944 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-24

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  1. 78 FR 75552 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-12

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  2. 78 FR 44942 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-25

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  3. 75 FR 82001 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  4. 76 FR 29732 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-23

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  5. 76 FR 36101 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-21

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  6. 75 FR 13268 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-19

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  7. 75 FR 65466 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-25

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  8. 77 FR 18243 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-27

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  9. 75 FR 27998 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-19

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  10. 75 FR 3455 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-21

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  11. 76 FR 59393 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-26

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  12. 78 FR 23241 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-18

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  13. 78 FR 12746 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  14. 77 FR 2714 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-19

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  15. 75 FR 51027 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-18

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  16. 75 FR 43518 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-26

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  17. 75 FR 71424 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-23

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  18. 77 FR 74836 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-18

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  19. 77 FR 58364 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-20

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  20. 75 FR 7576 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-22

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  1. 76 FR 28759 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-18

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  2. 75 FR 35447 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-22

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  3. 76 FR 22388 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-21

    ... Site-Specific Advisory Board (EM SSAB), Oak Ridge Reservation. The Federal Advisory Committee Act (Pub... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  4. Site-specific control of silica mineralization on DNA using a designed peptide.

    PubMed

    Ozaki, Makoto; Nagai, Kazuma; Nishiyama, Hiroto; Tsuruoka, Takaaki; Fujii, Satoshi; Endoh, Tamaki; Imai, Takahito; Tomizaki, Kin-Ya; Usui, Kenji

    2016-03-01

    We developed a site-specific method for precipitating inorganic compounds using organic compounds, DNA, and designed peptides with peptide nucleic acids (PNAs). Such a system for site-specific precipitation represents a powerful tool for use in nanobiochemistry and materials chemistry. PMID:26690695

  5. 76 FR 38143 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-29

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy, DOE... Site-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L... CONTACT: Gerri Flemming, Office of External Affairs, Department of Energy, Savannah River...

  6. FLP recombinase-mediated site-specific recombination in silkworm, Bombyx mori

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A comprehensive understanding of gene function and the production of site-specific genetically modified mutants are two major goals of genetic engineering in the post-genomic era. Although site-specific recombination systems have been powerful tools for genome manipulation of many organisms, they h...

  7. 75 FR 19630 - Environmental Management Site-Specific Advisory Board Charter Renewal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board Charter Renewal Pursuant to Section 14(a)(2)(A) of the... renewal of the Environmental Management Site- Specific Advisory Board has been determined to be...

  8. A cyclopropene-modified nucleotide for site-specific RNA labeling using genetic alphabet expansion transcription.

    PubMed

    Eggert, F; Kath-Schorr, S

    2016-06-01

    Site-specific RNA modification with methyl cyclopropene moieties is performed by T7 in vitro transcription. An existing unnatural base is functionalized with a cyclopropene moiety and used in transcription reactions to produce site-specifically cyclopropene-modified RNA molecules. The posttranscriptional inverse electron demand Diels-Alder cycloaddition reaction with a selected tetrazine-fluorophore conjugate is demonstrated. PMID:27181840

  9. 7 CFR 1726.404 - Non-site specific construction contract closeout.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE ELECTRIC SYSTEM CONSTRUCTION POLICIES AND PROCEDURES Contract Closeout § 1726.404 Non-site specific construction contract closeout. This section is applicable to... 7 Agriculture 11 2010-01-01 2010-01-01 false Non-site specific construction contract...

  10. 76 FR 28218 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-16

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific...: Purpose of the Board: The purpose of the Board is to make recommendations to DOE-EM and site management...

  11. 75 FR 48662 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-11

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Nevada Test Site. The Federal Advisory Committee Act (Pub. L. 92-463, 86...

  12. 77 FR 16542 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-21

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific...: Purpose of the Board: The purpose of the Board is to make recommendations to DOE-EM and site management...

  13. 77 FR 75627 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-21

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Nevada. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat....

  14. 40 CFR 170.232 - Knowledge of labeling and site-specific information.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Knowledge of labeling and site-specific information. 170.232 Section 170.232 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS WORKER PROTECTION STANDARD Standard for Pesticide Handlers § 170.232 Knowledge of labeling and site-specific...

  15. 76 FR 51362 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-18

    ... activities. Tentative Agenda 1. Update--Site-Specific Environmental Impact Statement Committee. 2. Update... advance of the meeting at the phone number listed above. Written statements may be filed with the Board... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice...

  16. 76 FR 53888 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-30

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance of the public at its...

  17. 75 FR 56527 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-16

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act.... Overview Legacy Management--Long-Term Land Use at Idaho National Laboratory. Integrated Waste...

  18. 78 FR 58294 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-23

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... SSAB, Idaho National Laboratory, welcomes the attendance of the public at its advisory...

  19. 77 FR 76475 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-28

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Laboratory/ICP Public Involvement/ Communications Sodium Bearing Waste Treatment Plant Update ICP End...

  20. 75 FR 9590 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-03

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Laboratory, welcomes the attendance of the public at its advisory committee meetings and will make...

  1. 75 FR 346 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Decision. Public Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance of...

  2. 77 FR 38276 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-27

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Management Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee... Center Status Public Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance...

  3. 76 FR 25682 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-05

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National ] Laboratory. The Federal Advisory Committee Act... National Laboratory, welcomes the attendance of the public at its advisory committee meetings and will...

  4. 75 FR 39008 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Laboratory, welcomes the attendance of the public at its advisory committee meetings and will make...

  5. 78 FR 12747 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance of the public at its...

  6. 76 FR 39080 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-05

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... National Laboratory (INL) 101. INL EM Budget. Calcine Path Forward. Advanced Mixed Waste Treatment...

  7. 77 FR 53192 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-31

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Closeout Process Public Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance...

  8. 75 FR 24685 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... to Cleanup Idaho National Laboratory Site Wide Review--CERCLA Long-Term Ecological Program...

  9. 76 FR 68179 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-03

    ... Management Site-Specific Advisory Board, Idaho National Laboratory (76 FR 66917). This document makes a... page at: http://inlcab.energy.gov/ . Correction In the Federal Register of October 28, 2011, in FR Doc... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of...

  10. 77 FR 65374 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... National Laboratory/ICP Public Involvement/ Communications Public Participation: The EM SSAB,...

  11. 75 FR 82004 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance of the public at its...

  12. 76 FR 10018 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-23

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Public Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance of the public...

  13. 77 FR 10485 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-22

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act...--Future Work Plan Public Participation: The EM SSAB, Idaho National Laboratory, welcomes the attendance...

  14. 76 FR 66917 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act... Environmental Assessment Public Participation: The EM SSAB, Idaho National Laboratory, welcomes the...

  15. 78 FR 30910 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-23

    ... Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Idaho National Laboratory. The Federal Advisory Committee Act...: The EM SSAB, Idaho National Laboratory, welcomes the attendance of the public at its...

  16. SITE-SPECIFIC RECOMBINATION FOR PLANT GENETIC ENGINEERING: STRATEGY FOR AGRO-MEDIATED GENE STACKING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The precise rearrangement of DNA in planta can be achieved through site-specific recombination. For the past decade and a half, laboratory experiments have shown that site-specific recombination can delete genomic DNA, regulate gene expression, recombine chromosomes, and target new DNA into designat...

  17. 40 CFR 60.2095 - What site-specific documentation is required?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false What site-specific documentation is... site-specific documentation is required? (a) Documentation must be available at the facility and....2055 through 60.2065. (9) Procedures for handling ash. (10) A list of the wastes burned during...

  18. 40 CFR 62.14620 - What site-specific documentation is required?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 9 2014-07-01 2014-07-01 false What site-specific documentation is... site-specific documentation is required? (a) Documentation must be available at the facility and....14580 through 62.14590. (9) Procedures for handling ash. (10) A list of the wastes burned during...

  19. 40 CFR 60.2095 - What site-specific documentation is required?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false What site-specific documentation is... site-specific documentation is required? (a) Documentation must be available at the facility and....2055 through 60.2065. (9) Procedures for handling ash. (10) A list of the wastes burned during...

  20. 40 CFR 62.14620 - What site-specific documentation is required?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 9 2012-07-01 2012-07-01 false What site-specific documentation is... site-specific documentation is required? (a) Documentation must be available at the facility and....14580 through 62.14590. (9) Procedures for handling ash. (10) A list of the wastes burned during...

  1. 40 CFR 60.2095 - What site-specific documentation is required?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false What site-specific documentation is... Training and Qualification § 60.2095 What site-specific documentation is required? (a) Documentation must... required under §§ 60.2055 through 60.2065. (9) Procedures for handling ash. (10) A list of the...

  2. 40 CFR 62.14620 - What site-specific documentation is required?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 9 2013-07-01 2013-07-01 false What site-specific documentation is... site-specific documentation is required? (a) Documentation must be available at the facility and....14580 through 62.14590. (9) Procedures for handling ash. (10) A list of the wastes burned during...

  3. 75 FR 64718 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-20

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... the areas of environmental restoration, waste management, and related activities. Tentative...

  4. 76 FR 51361 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-18

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy (DoE... Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L... Center, 1508 Paseo de Pueblo Sur, Taos, New Mexico. FOR FURTHER INFORMATION CONTACT: Menice...

  5. 76 FR 36101 - Environmental Management Site-Specific Advisory Board, Northern New Mexico; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-21

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico; Meeting AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L... Drive, Los Alamos, New Mexico. FOR FURTHER INFORMATION CONTACT: Menice Santistevan, Northern New...

  6. 78 FR 63171 - Environmental Management Site-Specific Advisory Board, Northern New Mexico; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico; Meeting AGENCY: Department of Energy... Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L... New Mexico 291, San Juan Pueblo, New Mexico 87566. FOR FURTHER INFORMATION CONTACT: Menice...

  7. On-the-go nitrogen sensing and fertilizer control for site-specific crop management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In-field site-specific nitrogen (N) management increases crop yield, reduces N application to minimize the risk of nitrate contamination of ground water, and thus reduces farming cost. Real-time N sensing and fertilization is required for efficient N management. An ‘on-the-go’ site-specific N manage...

  8. 76 FR 19003 - Land Disposal Restrictions: Nevada and California; Site Specific Treatment Variances for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-06

    ...: Proposed rule. SUMMARY: EPA is proposing to issue both a site-specific treatment variance to U.S. Ecology... proposes to issue both a site-specific treatment variance to U.S. Ecology Nevada (USEN) located in Beatty... section of this document. II. Does this action apply to me? This proposal applies only to U. S....

  9. 29 CFR 1926.752 - Site layout, site-specific erection plan and construction sequence.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Site layout, site-specific erection plan and construction... Steel Erection § 1926.752 Site layout, site-specific erection plan and construction sequence. (a... strength or sufficient strength to support the loads imposed during steel erection. (c) Site layout....

  10. 76 FR 80354 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-23

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  11. 76 FR 17118 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-28

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... Board is to make recommendations to DOE-EM and site management in the areas of environmental...

  12. 78 FR 61348 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-03

    ..., 2013 of the Environmental Management Site-Specific Advisory Board, Portsmouth (78 FR 56871). This... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy. ACTION: Notice of Cancellation of Open Meeting. SUMMARY: On September 16, 2013, in FR Doc. 2013-22453, on page...

  13. 78 FR 4139 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-18

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  14. 75 FR 17701 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-07

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... environmental restoration, waste management, and related activities. Tentative Agenda Topics: Wednesday,...

  15. 78 FR 49738 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-15

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  16. 78 FR 20311 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-04

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of Open Webinar. SUMMARY: This notice announces a webinar of the Environmental Management Site-Specific... recommendations to DOE-EM and site management in the areas of environmental restoration, waste management,...

  17. 77 FR 39234 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-02

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  18. 76 FR 5365 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-31

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  19. 76 FR 63613 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-13

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  20. 75 FR 13269 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-19

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  1. 77 FR 28368 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-14

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental ] Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  2. 78 FR 26635 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-07

    ... Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy. ACTION: Notice of... of open meeting announcing a meeting on May 16, 2013 of the Environmental Management Site-Specific Advisory Board, Paducah (78 FR 25064). This document makes a correction to that notice. FOR...

  3. 75 FR 2859 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-19

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  4. 77 FR 64112 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-18

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  5. 78 FR 68431 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-14

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  6. 77 FR 55813 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... Board is to make recommendations to DOE-EM and site management in the areas of environmental...

  7. 78 FR 59012 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-25

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... environmental restoration, waste management, and related activities. Tentative Agenda Topics: Wednesday,...

  8. 76 FR 50204 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-12

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of... (EIS) Committee of the Environmental Management Site- Specific Advisory Board (EM SSAB), Nevada. The... environmental restoration, waste management, and related activities. Purpose of the Committee: The purpose...

  9. 75 FR 51450 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-20

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... the Board is to make recommendations ] to DOE-EM and site management in the areas of...

  10. 78 FR 64208 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-28

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... environmental restoration, waste management, and related activities. Tentative Agenda Topics: Tuesday,...

  11. 77 FR 4027 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-26

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  12. 78 FR 64932 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-30

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... recommendations to DOE-EM and site management in the areas of environmental restoration, waste management,...

  13. 75 FR 6018 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-05

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... the Board is to make recommendations to DOE-EM and site management in the areas of...

  14. 77 FR 12044 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-28

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... recommendations to DOE-EM and site management in the areas of environmental restoration, waste management,...

  15. 75 FR 8050 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  16. 76 FR 20651 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-13

    ... Environmental Management Site-Specific Advisory Board Chairs (76 FR 17118). This notice announces the... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of cancellation of open meeting. SUMMARY: On March 28, 2011, in FR Doc. 2011-7243, on page 17118, the...

  17. 78 FR 23760 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-22

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  18. 76 FR 4645 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-26

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... management in the areas of environmental restoration, waste management, and related activities....

  19. 78 FR 53135 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-28

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... recommendations to DOE-EM and site management in the areas of environmental restoration, waste management,...

  20. 75 FR 82004 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  1. 75 FR 65310 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-22

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  2. 76 FR 52944 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-24

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of... (EIS) Committee of the Environmental Management Site- Specific Advisory Board (EM SSAB), Nevada. The... environmental restoration, waste management, and related activities. Purpose of the Committee: The purpose...

  3. 78 FR 28207 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-14

    ... Environmental Management Site-Specific Advisory Board, Hanford AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... and site management in the areas of environmental restoration, waste management, and...

  4. 76 FR 55370 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-07

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of... (EIS) Committee of the Environmental Management Site- Specific Advisory Board (EM SSAB), Nevada. The... environmental restoration, waste management, and related activities. Purpose of the Committee: The purpose...

  5. 77 FR 16021 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-19

    ... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site-Specific... recommendations to DOE-EM and site management in the areas of environmental restoration, waste management,...

  6. 40 CFR 62.14620 - What site-specific documentation is required?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 8 2011-07-01 2011-07-01 false What site-specific documentation is... POLLUTANTS Federal Plan Requirements for Commercial and Industrial Solid Waste Incineration Units That... site-specific documentation is required? (a) Documentation must be available at the facility...

  7. 40 CFR 60.2095 - What site-specific documentation is required?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Commercial and Industrial Solid Waste Incineration Units for Which Construction Is Commenced After November... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What site-specific documentation is... Training and Qualification § 60.2095 What site-specific documentation is required? (a) Documentation...

  8. 77 FR 26273 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-03

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy, DoE... Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L... New Mexico Citizens' Advisory Board (NNMCAB), 94 Cities of Gold Road, Santa Fe, NM 87506. Phone...

  9. 75 FR 24686 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy. ACTION... Management Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act...: Ohkay Owingeh Conference Center, North Taos Highway 68, San Juan Pueblo, New Mexico 87566. FOR...

  10. Site-specific fluorescence spectrum detection and characterization of hASIC1a channels upon toxin mambalgin-1 binding in live mammalian cells.

    PubMed

    Wen, Ming; Guo, Xiaoqi; Sun, Peibei; Xiao, Liang; Li, Juan; Xiong, Ying; Bao, Jin; Xue, Tian; Zhang, Longhua; Tian, Changlin

    2015-05-11

    The synthesis of fluorescent unnatural amino-acid Anap was optimized and the Anap was incorporated into four sites in an acid-pocket or a transmembrane region of human acid-sensing ion channel-1a (hASIC1a). Combinational Anap fluorescence spectra and patch-clamp electrophysiology data illustrated site-specific conformational responses upon toxin mambalgin-1 binding. This combinational approach can be used to analyse conformational properties of many different eukaryotic proteins in their functional states, in a site-specific manner in live mammalian cells. PMID:25873388

  11. Ammonium Sulfate Improves Detection of Hydrophilic Quaternary Ammonium Compounds through Decreased Ion Suppression in Matrix-Assisted Laser Desorption/Ionization Imaging Mass Spectrometry.

    PubMed

    Sugiyama, Eiji; Masaki, Noritaka; Matsushita, Shoko; Setou, Mitsutoshi

    2015-11-17

    Hydrophilic quaternary ammonium compounds (QACs) include derivatives of carnitine (Car) or choline, which are known to have essential bioactivities. Here we developed a technique for improving the detection of hydrophilic QACs using ammonium sulfate (AS) in matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS). In MALDI mass spectrometry for brain homogenates, the addition of AS greatly increased the signal intensities of Car, acetylcarnitine (AcCar), and glycerophosphocholine (GPC) by approximately 300-, 700-, and 2500-fold. The marked improvement required a higher AS concentration than that needed for suppressing the potassium adduction on phosphatidylcholine and 2,5-dihydroxybenzoic acid. Adding AS also increased the signal intensities of Car, AcCar, and GPC by approximately 10-, 20-, and 40-fold in MALDI-IMS. Consequently, the distributions of five hydrophilic QACs (Car, AcCar, GPC, choline, and phosphocholine) were simultaneously visualized by this technique. The distinct mechanism from other techniques such as improved matrix application, derivatization, or postionization suggests the great potential of AS addition to achieve higher sensitivity of MALDI-IMS for various analytes. PMID:26492538

  12. Site-Specific Ser/Thr/Tyr Phosphoproteome of Sinorhizobium meliloti at Stationary Phase

    PubMed Central

    Liu, Tao; Tian, Chang Fu; Chen, Wen Xin

    2015-01-01

    Sinorhizobium meliloti, a facultative microsymbiont of alfalfa, should fine-tune its cellular processes to live saprophytically in soils characterized with limited nutrients and diverse stresses. In this study, TiO2 enrichment and LC-MS/MS were used to uncover the site-specific Ser/Thr/Tyr phosphoproteome of S. meliloti in minimum medium at stationary phase. There are a total of 96 unique phosphorylated sites, with a Ser/Thr/Tyr distribution of 63:28:5, in 77 proteins. Phosphoproteins identified in S. meliloti showed a wide distribution pattern regarding to functional categories, such as replication, transcription, translation, posttranslational modification, transport and metabolism of amino acids, carbohydrate, inorganic ion, succinoglycan etc. Ser/Thr/Tyr phosphosites identified within the conserved motif in proteins of key cellular function indicate a crucial role of phosphorylation in modulating cellular physiology. Moreover, phosphorylation in proteins involved in processes related to rhizobial adaptation was also discussed, such as those identified in SMa0114 and PhaP2 (polyhydroxybutyrate synthesis), ActR (pH stress and microaerobic adaption), SupA (potassium stress), chaperonin GroEL2 (viability and potentially symbiosis), and ExoP (succinoglycan synthesis and secretion). These Ser/Thr/Tyr phosphosites identified herein would be helpful for our further investigation and understanding of the role of phosphorylation in rhizobial physiology. PMID:26401955

  13. Membrane blebbing as a recovery manoeuvre in site-specific sonoporation mediated by targeted microbubbles

    PubMed Central

    Leow, Ruen Shan; Wan, Jennifer M. F.; Yu, Alfred C. H.

    2015-01-01

    Site-specific perforation of the plasma membrane can be achieved through ultrasound-triggered cavitation of a single microbubble positioned adjacent to the cell. However, for this perforation approach (sonoporation), the recovery manoeuvres invoked by the cell are unknown. Here, we report new findings on how membrane blebbing can be a recovery manoeuvre that may take place in sonoporation episodes whose pores are of micrometres in diameter. Each sonoporation site was created using a protocol involving single-shot ultrasound exposure (frequency: 1 MHz; pulse length: 30 cycles; peak negative pressure: 0.45 MPa) which triggered inertial cavitation of a single targeted microbubble (diameter: 1–5 µm). Over this process, live confocal microscopy was conducted in situ to monitor membrane dynamics, model drug uptake kinetics and cytoplasmic calcium ion (Ca2+) distribution. Results show that blebbing would occur at a recovering sonoporation site after its resealing, and it may emerge elsewhere along the membrane periphery. The bleb size was correlated with the pre-exposure microbubble diameter, and 99% of blebbing cases at sonoporation sites were inflicted by microbubbles larger than 1.5 µm diameter (analysed over 124 sonoporation episodes). Blebs were not observed at irreversible sonoporation sites or when sonoporation site repair was inhibited via extracellular Ca2+ chelation. Functionally, the bleb volume was found to serve as a buffer compartment to accommodate the cytoplasmic Ca2+ excess brought about by Ca2+ influx during sonoporation. These findings suggest that membrane blebbing would help sonoporated cells restore homeostasis. PMID:25694544

  14. Amorphous Semiconductor Nanowires Created by Site-Specific Heteroatom Substitution with Significantly Enhanced Photoelectrochemical Performance.

    PubMed

    He, Ting; Zu, Lianhai; Zhang, Yan; Mao, Chengliang; Xu, Xiaoxiang; Yang, Jinhu; Yang, Shihe

    2016-08-23

    Semiconductor nanowires that have been extensively studied are typically in a crystalline phase. Much less studied are amorphous semiconductor nanowires due to the difficulty for their synthesis, despite a set of characteristics desirable for photoelectric devices, such as higher surface area, higher surface activity, and higher light harvesting. In this work of combined experiment and computation, taking Zn2GeO4 (ZGO) as an example, we propose a site-specific heteroatom substitution strategy through a solution-phase ions-alternative-deposition route to prepare amorphous/crystalline Si-incorporated ZGO nanowires with tunable band structures. The substitution of Si atoms for the Zn or Ge atoms distorts the bonding network to a different extent, leading to the formation of amorphous Zn1.7Si0.3GeO4 (ZSGO) or crystalline Zn2(GeO4)0.88(SiO4)0.12 (ZGSO) nanowires, respectively, with different bandgaps. The amorphous ZSGO nanowire arrays exhibit significantly enhanced performance in photoelectrochemical water splitting, such as higher and more stable photocurrent, and faster photoresponse and recovery, relative to crystalline ZGSO and ZGO nanowires in this work, as well as ZGO photocatalysts reported previously. The remarkable performance highlights the advantages of the ZSGO amorphous nanowires for photoelectric devices, such as higher light harvesting capability, faster charge separation, lower charge recombination, and higher surface catalytic activity. PMID:27494205

  15. Adsorption isotherms, kinetics, thermodynamics and desorption studies for uranium and thorium ions from aqueous solution by novel microporous composite P(HEMA-EP)

    NASA Astrophysics Data System (ADS)

    Akkaya, Recep; Akkaya, Birnur

    2013-03-01

    In this research, a novel composite, poly(2-hydroxyethylmethacrylate-expanded perlite) [P(HEMA-EP)], was synthesized and its adsorptive features were investigated. P(HEMA-EP)'s adsorptive features were evaluated for UO22+ and Th4+ ions in terms of the dependency upon the ion concentration, pH, temperature, and time. P(HEMA-EP) was able to bind UO22+ and Th4+ ions with strong chemical affinity. The adsorption results were fitted to the classical Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) sorption models. P(HEMA-EP) was also used to study the removal of UO22+ and Th4+ ions from aqueous solutions in a batch system. The adsorption capacity (XL) of UO22+ and Th4+ ions was found to be 0.29 and 0.44 mol kg-1, respectively. The kinetic data corresponds well to the pseudo-second-order equation. Changes in the enthalpy and entropy values demonstrated that the overall adsorption process was spontaneous (ΔG < 0), endothermic (ΔH > 0), and had increased entropy (ΔS > 0), as expected. The reusability of the composites was confirmed for five sequential reuses.

  16. Characterization of gallotannins from Astronium species by flow injection analysis- electrospray ionization-ion trap-tandem mass spectrometry and matrix-assisted laser desorption/ionization time-of- flight mass spectrometry.

    PubMed

    da Silva, Viviane Cândida; Napolitano, Assunta; Eletto, Daniela; Rodrigues, Clenilson Martins; Pizza, Cosimo; Vilegas, Wagner

    2011-01-01

    The species Astronium urundeuva (Allemao) Engl. and Astronium graveolens Jacq., which are used in Brazilian folk medicine to treat allergies, inflammation, diarrhea and ulcers, were investigated for their composition. The aim of this study was to define a rapid and reliable analytical approach, based on the flow-injection analysis-electrospray ionization-ion trap-tandem mass spectrometry (FIA-ESI-IT-MS-MS) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-ToF-MS), to investigate the full range of hydrolyzable tannins present in the extracts of these Astronium species. The MALDI-ToF-MS analysis allowed us to ascertain the presence of hydrolysable tannins in both Astronium species as a series of gallotannins with degrees of polymerization of 7 to 13 galloyl units. Moreover, the analysis by FIA-ESI-IT-MS-MS, as well as confirming this result and chemically defining gallotannins as galloylglucose compounds, highlighted the presence of further classes of hydrolysable tannins, such as hexahydrodiphenoyl esters of glucose and some gallic acid derivatives, providing information about their structure by a careful study of their fragmentation patterns. Finally, the evaluation of the number of positional isomers of gallotannins occurring in both Astronium species was obtained by high-performance liquid chromatography-electrospray ionization-ion trap mass spectrometry (HPLC/ESI-IT-MS). This is the first mass spectrometric evidence relating to the existence of gallotannins in Astronium genus. PMID:22006629

  17. Molecular characterization of S- and N-containing organic constituents in ambient aerosols by negative ion mode high-resolution Nanospray Desorption Electrospray Ionization Mass Spectrometry: CalNex 2010 field study

    NASA Astrophysics Data System (ADS)

    O'Brien, Rachel E.; Laskin, Alexander; Laskin, Julia; Rubitschun, Caitlin L.; Surratt, Jason D.; Goldstein, Allen H.

    2014-11-01

    Samples of ambient aerosols from the 2010 California Research at the Nexus of Air Quality and Climate Change (CalNex) field study were analyzed using negative ion mode Nanospray Desorption Electrospray Ionization High-Resolution Mass Spectrometry (nano-DESI/MS). Four samples per day (6 h each) were collected in Bakersfield, CA on 20-24 June. Four characteristic groups were identified: molecules composed of carbon, hydrogen, and oxygen only (CHO), sulfur- (CHOS), nitrogen- (CHON), and both nitrogen- and sulfur-containing organics (CHONS). The chemical formula and elemental ratios were consistent with the presence of organonitrates, organosulfate, and nitroxy organosulfates in the negative ion mode mass spectra. The number of observed CHO compounds increased in the afternoon samples, suggesting photochemical processing as a source. The average number of CHOS compounds had the smallest changes during the day, consistent with a more broadly distributed source. Both of the nitrogen-containing groups (CHONS and CHON) had greater numbers of compounds in the early morning (midnight to 6 A.M.) and night (6 P.M. to midnight) samples, respectively, consistent with nitrate radical chemistry as a likely source for those compounds. Most of the compounds were found in submicron particles. The size distribution of the number of CHON compounds was bimodal, potentially indicating two types of sources. We conclude that the majority of the compounds observed were secondary in nature with both biogenic and anthropogenic sources. These data are complementary to previous results from positive ion mode nano-DESI/MS analysis of a subset of the same samples providing a more complete view of aerosol chemical composition at Bakersfield.

  18. Development of site-specific earthquake response spectra for eastern US sites

    SciTech Connect

    Beavers, J.E.; Brock, W.R.; Hunt, R.J.; Shaffer, K.E.

    1993-08-01

    Site-specific earthquake, uniform-hazard response spectra have been defined for the Department of Energy Oak Ridge, Tennessee, and Portsmouth, Ohio, sites for use in evaluating existing facilities and designing new facilities. The site-specific response spectra were defined from probabilistic and deterministic seismic hazard studies following the requirements in DOE-STD-1024-92, ``Guidelines for Probabilistic Seismic Hazard Curves at DOE Sites.` For these two sites, the results show that site-specific uniform-hazard response spectra are slightly higher in the high-frequency range and considerably lower in the low-frequency range compared with response spectra defined for these sites in the past.

  19. [Advances in the study of site-specific antibody-drug conjugates].

    PubMed

    Sun, Yu; Huang, Rong; Sun, Bai-wang

    2015-10-01

    Antibody drug conjugates (ADCs) are an emerging class of targeted therapeutics with the potential to improve therapeutic index over the traditional chemotherapy. However, it is difficult to control the site and stoichiometry of conjugation in mAb, typically resulting in heterogeneous mixtures of ADCs that are difficult to optimize. New methods for site-specific drug attachment allow development of more homogeneous conjugates and control of the site of drug attachment. In this article, the new literature on development of ADCs and site-specific ADCs is reviewed. In addition, we summarized the various strategies in production of site-specific ADCs. PMID:26837166

  20. NEXAFS spectroscopy and site-specific fragmentation of N-methylformamide, N,N-dimethylformamide, and N,N-dimethylacetamide

    NASA Astrophysics Data System (ADS)

    Salén, Peter; Yatsyna, Vasyl; Schio, Luca; Feifel, Raimund; Richter, Robert; Alagia, Michele; Stranges, Stefano; Zhaunerchyk, Vitali

    2016-06-01

    Near-edge X-ray absorption fine-structure (NEXAFS) spectra measured at the C, N, and O K-edges for three molecules containing the amide moiety, N-methylformamide (HCONHCH3), N,N-dimethylformamide (HCON(CH3)2), and N,N-dimethylacetamide (CH3CON(CH3)2) are presented. These molecules have similar structures and differ by the number of methyl groups located at the molecular ends. The fragmentation of these molecules after resonant excitation at different K-edge resonances is also investigated, using a 3D-ion imaging time-of-flight spectrometer. A comparison between the molecules with respect to the relative contributions of the fragments created upon excitation at distinct resonances reveals site-specific fragmentation. Further information about the character of the core-excitation and dissociation process is obtained from the angular distributions of the ion fragments.

  1. Thermal desorption of deuterium implanted into beryllium

    SciTech Connect

    Markin, A.V.; Chernikov, V.N.; Zakharov, A.P.

    1995-09-01

    By means of TDS measurements it is shown that the desorption of deuterium from Be implanted with 5 keV D ions to fluences, {Phi}, from 1x10{sup 20} D/m{sup 2} to 1x10{sup 21} D/m{sup 2} proceeds in one high temperature stage B, while at {Phi} {ge} 1.2x10{sup 21}D/m{sup 2} one more stage A is added. The desorption maximum A is narrow and consists of two peaks A{sub 1} and A{sub 2} at about 460 K and 490 K, respectively. Peak A{sub 1} is attributed to the desorption of deuterium from the walls of opened channels formed under D ion implantation. Peak {sub A}2 is a consequence of the opening of a part of closed bubbles/channels to the outer surface. The position of maximum B shifts noticeably and nonsteadily on the fluence in a range from 850 to 1050 K. The origin of this maximum is the liberation of D atoms bound at vacancy complexes discussed previously by Wampler. The dependence of Tm(B) on the fluence is governed by the interaction of freely migrating D atoms with partly opened or fully closed gas cavity arrangements which are created under temperature ramping, but differently in specimens implanted with D ions to different fluences.

  2. Light-stimulated cargo release from a core-shell structured nanocomposite for site-specific delivery

    NASA Astrophysics Data System (ADS)

    Cai, Yun; Ling, Li; Li, Xiaofang; Chen, Meng; Su, Likai

    2015-03-01

    This paper reported a core-shell structured site-specific delivery system with a light switch triggered by low energy light (λ=510 nm). Its core was composed of supermagnetic Fe3O4 nanoparticles for magnetic guiding and targeting. Its outer shell consisted of mesoporous silica molecular sieve MCM-41 which offered highly ordered hexagonal tunnels for cargo capacity. A light switch N1-(4aH-cyclopenta[1,2-b:5,4-b‧]dipyridin-5(5aH)-ylidene)benzene-1,4-diamine (CBD) was covalently grafted into these hexagonal tunnels, serving as light stimuli acceptor with loading content of 1.1 μM/g. This composite was fully characterized and confirmed by SEM, TEM, XRD patterns, N2 adsorption/desorption, thermogravimetric analysis, IR, UV-vis absorption and emission spectra. Experimental data suggested that this composite had a core as wide as 150 nm and could be magnetically guided to specific sites. Its hexagonal tunnels were as long as 180 nm. Upon light stimuli of "on" and "off" states, controllable release was observed with short release time of ~900 s (90% capacity).

  3. SUPPORTING THE REDEVELOPMENT OF BROWNFIELD SITES USING SITE-SPECIFIC MANAGEMENT APPROACHES AND REDEVELOPMENT TOOLS (SMART)

    EPA Science Inventory

    The Site-Specific Management Approaches and Redevelopment Tools (SMART) provides potential solutions for facilitating the redevelopment of brownfield sites. The term "brownfield site" refers to previously developed property whose reuse may be complicated by the presence of hazar...

  4. 40 CFR 60.3019 - What site-specific documentation is required?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Model Rule-Operator Training and Qualification § 60.3019 What site-specific documentation is required... air supply levels. (5) Procedures for operating the incinerator and associated air pollution...

  5. 40 CFR 60.3019 - What site-specific documentation is required?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Model Rule-Operator Training and Qualification § 60.3019 What site-specific documentation is required... air supply levels. (5) Procedures for operating the incinerator and associated air pollution...

  6. 40 CFR 60.3019 - What site-specific documentation is required?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Model Rule-Operator Training and Qualification § 60.3019 What site-specific documentation is required... air supply levels. (5) Procedures for operating the incinerator and associated air pollution...

  7. 40 CFR 60.3019 - What site-specific documentation is required?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Model Rule-Operator Training and Qualification § 60.3019 What site-specific documentation is required... air supply levels. (5) Procedures for operating the incinerator and associated air pollution...

  8. 78 FR 75552 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-12

    ... and Remediation Committee and Waste Management Committee of the Environmental Management Site-Specific... restoration, waste management, and related activities. Purpose of the Environmental Monitoring and Remediation... environmental remediation activities resulting from historical Los Alamos National Laboratory operations and,...

  9. 77 FR 11516 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-27

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy (DOE). ACTION... FURTHER INFORMATION CONTACT: Reinhard Knerr, Deputy Designated Federal Officer, Department of...

  10. 77 FR 20014 - Environmental Management Site-Specific Advisory Board, Paducah, KY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-03

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Paducah, KY AGENCY: Department of Energy (DOE). ACTION... FURTHER INFORMATION CONTACT: Reinhard Knerr, Deputy Designated Federal Officer, Department of...

  11. 77 FR 51789 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-27

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy (DOE). ACTION... FURTHER INFORMATION CONTACT: Reinhard Knerr, Deputy Designated Federal Officer, Department of...

  12. Site specific irrigation management-Precision agriculture for improved water use efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Precision agriculture involves aspects of sensing, crop protection, field sampling, precision tillage and planting, fertilizer application, pest control, irrigation, on-the-go yield monitoring and other emerging applications. Site specific irrigation management (SSIM) focuses on the delivery of app...

  13. A METHOD FOR THE MEASUREMENT OF SITE-SPECIFIC TAUTOMERIC AND ZWITTERIONIC MICROSPECIES EQUILIBRIUM CONSTANTS

    EPA Science Inventory

    We describe a method for the individual measurement of simultaneously occurring, unimolecular, site-specific "microequilibrium" constants as in, for example, prototropic tautomerism and zwitterionic equilibria. Our method represents an elaboration of that of Nygren et al. (Anal. ...

  14. METHOD FOR THE MEASUREMENT OF SITE-SPECIFIC TAUTOMERIC AND ZWITTERIONIC MICROSPECIES EQUILIBRIUM CONSTANTS

    EPA Science Inventory

    We describe a method for the individual measurement of simultaneously occurring, unimolecular, site-specific “microequilibrium” constants as in, for example, prototropic tautomerism and zwitterionic equilibria. Our method represents an elaboration of that of Nygren et al. (Anal. ...

  15. SMART GUIDANCE AND SMARTE - TOOLS FOR DEVELOPING SITE SPECIFIC REDEVELOPMENT PLANS

    EPA Science Inventory

    Site-specific Management Approaches and Redevelopment Tools (SMART) Guidance and its electronic counterpart, SMARTe are being developed jointly with the German Federal Ministry of Education and Research and the Interstate Technology Regulatory Council. These products will assist ...

  16. 75 FR 82003 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... environmental restoration, waste management and related activities. Tentative Agenda: Call to...

  17. 76 FR 78909 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-20

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... environmental restoration, waste management, and related activities. Tentative Agenda Call to...

  18. 76 FR 64329 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-18

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... environmental restoration, waste management and related activities. Tentative Agenda: Call to...

  19. 76 FR 8359 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-14

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... environmental restoration, waste management and related activities. Tentative Agenda Call to...

  20. 78 FR 10611 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-14

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... environmental restoration, waste management and related activities. Tentative Agenda Call to...

  1. 75 FR 7577 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-22

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... environmental restoration, waste management and related activities. Tentative Agenda: Call to...

  2. Mass spectrometric characterization of transglutaminase based site-specific antibody-drug conjugates.

    PubMed

    Farias, Santiago E; Strop, Pavel; Delaria, Kathy; Galindo Casas, Meritxell; Dorywalska, Magdalena; Shelton, David L; Pons, Jaume; Rajpal, Arvind

    2014-02-19

    Antibody drug conjugates (ADCs) are becoming an important new class of therapeutic agents for the treatment of cancer. ADCs are produced through the linkage of a cytotoxic small molecule (drug) to monoclonal antibodies that target tumor cells. Traditionally, most ADCs rely on chemical conjugation methods that yield heterogeneous mixtures of varying number of drugs attached at different positions. The potential benefits of site-specific drug conjugation in terms of stability, manufacturing, and improved therapeutic index has recently led to the development of several new site-specific conjugation technologies. However, detailed characterization of the degree of site specificity is currently lacking. In this study we utilize mass spectrometry to characterize the extent of site-specificity of an enzyme-based site-specific antibody-drug conjugation technology that we recently developed. We found that, in addition to conjugation of the engineered site, a small amount of aglycosylated antibody present in starting material led to conjugation at position Q295, resulting in approximately 1.3% of off-target conjugation. Based on our detection limits, we show that Q295N mutant eliminates the off-target conjugation yielding highly homogeneous conjugates that are better than 99.8% site-specific. Our study demonstrates the importance of detailed characterization of ADCs and describes methods that can be utilized to characterize not only our enzyme based conjugates, but also ADCs generated by other conjugation technologies. PMID:24359082

  3. Desorption from interstellar grains

    NASA Technical Reports Server (NTRS)

    Leger, A.; Jura, M.; Omont, A.

    1985-01-01

    Different desorption mechanisms from interstellar grains are considered to resolve the conflict between the observed presence of gaseous species in molecular clouds and their expected depletion onto grains. The physics of desorption is discussed with particular reference to the process of grain heating and the specific heat of the dust material. Impulsive heating by X-rays and cosmic rays is addressed. Spot heating of the grains by cosmic rays and how this can lead to desorption of mantles from very large grains is considered. It is concluded that CO depletion on grains will be small in regions with A(V) less than five from the cloud surface and n(H) less than 10,000, in agreement with observations and in contrast to expectations from pure thermal equilibrium. Even in very dense and obscured regions and in the absence of internal ultraviolet sources, the classical evaporation of CO or N2 and O2-rich mantles by cosmic rays is important.

  4. Application and field test of a mobile thermal desorption - single photon ionization - ion trap mass spectrometer (TD-SPI-ITMS) for trace detection of security relevant substances

    NASA Astrophysics Data System (ADS)

    Schramm, Elisabeth; Heindl, Thomas; Hölzer, Jasper; McNeish, Alexander; Puetz, Michael; Ries, Hermann; Schall, Patricia; Schulte-Ladbeck, Rasmus; Schultze, Rainer; Sklorz, Martin; Spieker, Gerd; Trebbe, Roman; Ulrich, Andreas; Wieser, Jochen; Zimmermann, Ralf

    2009-05-01

    The objective of this accomplished project funded by the German BMBF was to develop a single photon ionization ion trap mass spectrometer (SPI-ITMS) for detection of security relevant substances in complex matrices at low concentrations. The advantage of such a soft ionization technique is a reduction of target ion fragmentation allowing identification of signals from complex matrices and enabling MS/MS capability. To obtain low detection limits, the applied photon energy has to be below the ionization potential (IP) of the bulk matrix components. Therefore, photon energies between 8 eV (155 nm) and 12 eV (103 nm) are necessary which was achieved with newly developed electron beam excimer lamps (EBEL). They generate light at different wavelengths depending on the selected rare gas emitting wavelengths adapted to the analyzed substances. So, e.g. with a krypton-EBEL with 8.4 eV photon energy most narcotics can be ionized without notable fragmentation. Due to their higher IPs, EBEL with higher photon energy have to be used for most explosives. Very low false-positive and false-negative rates have been achieved using MS/MS studies. First field tests of a demonstrator provided the proof of principle.

  5. Facile Synthesis of N-Doped Carbon Dots as a New Matrix for Detection of Hydroxy-Polycyclic Aromatic Hydrocarbons by Negative-Ion Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry.

    PubMed

    Lu, Wenjing; Li, Yong; Li, Ruijin; Shuang, Shaomin; Dong, Chuan; Cai, Zongwei

    2016-05-25

    N-doping carbon dots (N-CDs) were prepared by microwave-assisted pyrolysis of dl-malic acid and ethanolamine as precursors. The material served as an excellent matrix for the detection of the environmental pollutants hydroxy-polycyclic aromatic hydrocarbons (OH-PAHs) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in negative ion mode. The obtained N-CDs exhibited good UV absorption capacity and favorable solubility. The use of the N-CDs matrix exhibited low matrix background interference and was beneficial to improve the signal response due to the specific π-conjugated polyaromatic structure and the doping of nitrogen atoms. The developed method was found to have good reproducibility and sensitivity. The N-CDs as a new matrix also were employed for the detection of OH-PAHs in real PM2.5 samples. The mass concentrations of Σ-hydroxy-pyrene, Σ-dihydroxy-anthraquinone, and Σ-dihydroxy-benzo(a)pyrene on the collected PM2.5 samples ranged from 0.125 to 0.136 ng/m(3), 0.039 to 0.052 ng/m(3), and 0.053 to 0.072 ng/m(3), respectively. This work extends the application field of N-CDs and provides a good candidate of matrix for MALDI-TOF MS detection of environmental pollutants. PMID:27180617

  6. On-column tryptic mapping of proteins using metal-ion-chelated magnetic silica microspheres by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    PubMed

    Li, Yan; Yan, Bo; Xu, Xiuqing; Deng, Chunhui; Yang, Pengyuan; Shen, Xizhong; Zhang, Xiangmin

    2007-01-01

    Peptide mapping analysis, utilizing an easily replaceable and regenerable on-column enzymatic microreactor with metal-ion-chelated adsorption of enzyme on magnetic silica microspheres, combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), was developed. Firstly, magnetic microspheres of small size and strong magnetism were prepared through solvothermal reaction. Thereafter, by introducing tetraethyl orthosilicate (TEOS), magnetic silica (MS) microspheres were formed. Trypsin could then be immobilized onto the MS microspheres based on the Lewis acid-base interaction through the divalent cation chelators such as iminodiacetic acid (IDA), which was chemically bound to the microspheres through the introduction of glycidoxypropyltrimethoxysilane (GLYMO). The trypsin-immobilized MS microspheres were then locally packed into the capillary by the application of a strong magnetic field using a magnet. The performance of the method was exemplified with digestion of bovine serum albumin for 5 min at 50 degrees C and the result was comparable to the 12 h in-solution digestion. The ability of regeneration of the prepared on-column microreactor and good reproducibility of microreactor before and after regeneration were also demonstrated. PMID:17577873

  7. Beryllium Desorption from Sediments

    NASA Astrophysics Data System (ADS)

    Boschi, V.; Willenbring, J. K.

    2015-12-01

    Beryllium isotopes have provided a useful tool in the field of geochronology and geomorphology over the last 25 years. The amount of cosmogenic meteoric 10Be and native 9Be absorbed to soils often scales with the residence time and chemical weathering of sediments in a landscape, respectively. Thus, the concentrations in river sediment may be used to quantify the denudation of specific watersheds. When deposited in ocean sediment, these concentrations are thought to record the history of denudation on Earth over the last ~10 Ma. The use of both isotopes often relies on the premise of beryllium retention to sediment surfaces in order to preserve a landscape's erosion and weathering signature. Changes in setting, en route from the soil to fluvial system to the ocean, can cause beryllium desorption and may preclude some applications of the 10Be/9Be system. Four mechanisms were tested to determine the desorption potential of beryllium including a reduction in pH, an increase in ionic strength and complexation with soluble organic and inorganic species. These processes have the potential to mobilize beryllium into solution. For example, by both reducing the pH and increasing the ionic strength, competition for adsorption sites increases, potentially liberating beryllium from the sediment surface. In addition, organic and inorganic ligands can complex beryllium causing it to become mobilized. To determine which of these alterations influence beryllium desorption and to quantify the effect, we prepared separate solutions of beryllium bound to minerals and organic compounds and measured beryllium concentrations in solution before and after adjusting the pH, ionic strength, and changing inorganic and organic ligand concentrations. We conclude from our observations that overall, beryllium sorbed to organic compounds was more resistant to desorption relative to mineral-associated beryllium. Among the methods tested, a reduction in pH resulted in the greatest amount of

  8. How Suitable is Matrix-Assisted Laser Desorption/Ionization-Time-of-Flight for Metabolite Imaging from Clinical Formalin-Fixed and Paraffin-Embedded Tissue Samples in Comparison to Matrix-Assisted Laser Desorption/Ionization-Fourier Transform Ion Cyclotron Resonance Mass Spectrometry?

    PubMed

    Buck, Achim; Balluff, Benjamin; Voss, Andreas; Langer, Rupert; Zitzelsberger, Horst; Aichler, Michaela; Walch, Axel

    2016-05-17

    In research and clinical settings, formalin-fixed and paraffin-embedded (FFPE) tissue specimens are collected routinely and therefore this material constitutes a highly valuable source to gather insight in metabolic changes of diseases. Among mass spectrometry techniques to examine the molecular content of FFPE tissue, mass spectrometry imaging (MSI) is the most appropriate when morphological and histological features are to be related to metabolic information. Currently, high-resolution mass spectrometers are widely used for metabolomics studies. However, with regards to matrix-assisted laser desorption/ionization (MALDI) MSI, no study has so far addressed the necessity of instrumental mass resolving power in terms of clinical diagnosis and prognosis using archived FFPE tissue. For this matter we performed for the first time a comprehensive comparison between a high mass resolution Fourier-transform ion cyclotron resonance (FTICR) mass spectrometer and a time-of-flight (TOF) instrument with lower mass resolving power. Spectra analysis revealed that about one-third of the detected peaks remained unresolved by MALDI-TOF, which led to a 3-5 times lower number of m/z features compared to FTICR measurements. Overlaid peak information and background noise in TOF images made a precise assignment of molecular attributes to morphological features more difficult and limited classification approaches. This clearly demonstrates the need for high-mass resolution capabilities for metabolite imaging. Nevertheless, MALDI-TOF allowed reproducing and verifying individual markers identified previously by MALDI-FTICR MSI. The systematic comparison gives rise to a synergistic combination of the different MSI platforms for high-throughput discovery and validation of biomarkers. PMID:27065343

  9. High-resolution and site-specific scanning spreading resistance microscopy and its applications to silicon devices

    SciTech Connect

    Zhang, L.; Koike, M.; Takeno, S.; Hara, K.

    2012-11-06

    Due to the continuous reduction of the critical dimensions of semiconductor devices, it becomes very important to know the two dimensional (2D) doping profile for improving device performance. Scanning spreading resistance microscopy (SSRM) performed in high vacuum is a powerful technique for quantitative 2D-doping profiling, with high spatial resolution and wide dynamic range of carrier concentration, as well as capability of site-specific analysis for accurate position. In this paper, we review SSRM applications to source/drain engineering in Si devices and their correlation with device characteristics by demonstrating several case studies. Direct observation of (110)/(100) CMOSFETs clarified significant differences between both pFETs and nFETs on (110) and (100) silicon substrates, revealing 2D channeling effect of boron ion implantation in pFETs; as well as silicidation impact on junction leakage-current characteristics in nFETs. Furthermore, our sample-preparation breakthrough enables site-specific SSRM characterization within 60 nm ultra thin samples and therefore failure analysis of real SRAM devices, demonstrating the high potential of SSRM technology for further device scaling and for failure analysis.

  10. Site-specific Pt Deposition and Etching on Electrically and Thermally Isolated SiO2 Micro-disk Surfaces

    SciTech Connect

    Saraf, Laxmikant V.

    2010-03-22

    Electrically and thermally isolated surfaces are often crucial for improving the detection sensitivity of microelectronic sensors. The site specific in-situ growth of Pt nano-rods on thermally and electrically isolated micro-fabricated SiO2 disks using wet chemical etching and focused ion/electron dual-beam (FIB-SEM) is demonstrated in this work. Fabrication of an array of micro-cavities on top of micro-disk is also demonstrated. FIB source is also utilized to fabricate through-holes in the micro-disks. The nature of Ga Gaussian distribution in the Ga-implanted region using a FIB source can naturally create more conducting layer on the sidewalls of through-holes on the micro-disks. Some sensor design concepts based on micro-fabrication of SiO2 micro-disks utilizing thermally and electrically isolated surfaces are discussed from the viewpoint of applications in photonics and bio-sensing.

  11. Industrial energy conservation-center-pivot site specific irrigation. Final report, January 1995--December 1996

    SciTech Connect

    McCann, I.R.; King, B.A.; Brady, R.

    1996-12-27

    This project was to aid in the development and commercial transfer of site specific technology to industry and farmers. This report contains the results of data collected during the fall of 1996 on a site near Aberdeen, Idaho. This site was equipped to apply water at variable rates predetermined by a digital control map that resided in a computer controller. The flow rates were then adjusted to maintain desired pressure with an Adjustable Speed Drive. Energy consumption was monitored during implementation of site specific irrigation practices and normal irrigation practices. This final report covers the impact that site specific irrigation has on energy use on a irrigated small grain crop near Aberdeen, Idaho. 3 refs., 20 figs., 1 tab.

  12. Bifunctional chelating agent for the design and development of site specific radiopharmaceuticals and biomolecule conjugation strategy

    DOEpatents

    Katti, Kattesh V.; Prabhu, Kandikere R.; Gali, Hariprasad; Pillarsetty, Nagavara Kishore; Volkert, Wynn A.

    2003-10-21

    There is provided a method of labeling a biomolecule with a transition metal or radiometal in a site specific manner to produce a diagnostic or therapeutic pharmaceutical compound by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radio metal or a transition metal, and covalently linking the resulting metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. Also provided is a method of synthesizing the --PR.sub.2 containing biomolecules by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radiometal or a transition metal, and covalently linking the resulting radio metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. There is provided a therapeutic or diagnostic agent comprising a --PR.sub.2 containing biomolecule.

  13. Outside the Box: Site-Specific Productions Put the Audience and the Actors in a New Light.

    ERIC Educational Resources Information Center

    Cantor, Jon

    2002-01-01

    Suggests site-specific theatrical productions can create innovative productions in nontraditional spaces. Discusses the experiences of the author as he directed a site-specific production (Wendy MacLeod's "The Shallow End," set at an indoor pool) and addresses the lessons he learned from it. Includes advice on creating site-specific productions.…

  14. Versatile and Efficient Site-Specific Protein Functionalization by Tubulin Tyrosine Ligase.

    PubMed

    Schumacher, Dominik; Helma, Jonas; Mann, Florian A; Pichler, Garwin; Natale, Francesco; Krause, Eberhard; Cardoso, M Cristina; Hackenberger, Christian P R; Leonhardt, Heinrich

    2015-11-01

    A novel chemoenzymatic approach for simple and fast site-specific protein labeling is reported. Recombinant tubulin tyrosine ligase (TTL) was repurposed to attach various unnatural tyrosine derivatives as small bioorthogonal handles to proteins containing a short tubulin-derived recognition sequence (Tub-tag). This novel strategy enables a broad range of high-yielding and fast chemoselective C-terminal protein modifications on isolated proteins or in cell lysates for applications in biochemistry, cell biology, and beyond, as demonstrated by the site-specific labeling of nanobodies, GFP, and ubiquitin. PMID:26404067

  15. Site-specific carbon deposition for hierarchically ordered core/shell-structured graphitic carbon with remarkable electrochemical performance.

    PubMed

    Lv, Yingying; Wu, Zhangxiong; Qian, Xufang; Fang, Yin; Feng, Dan; Xia, Yongyao; Tu, Bo; Zhao, Dongyuan

    2013-10-01

    A fascinating core-shell-structured graphitic carbon material composed of ordered microporous core and uniform mesoporous shell is fabricated for the first time through a site-specific chemical vapor deposition process by using a nanozeolite@mesostructured silica composite molecular sieve as the template. The mesostructure-directing agent cetyltrimethylammonium bromide in the shell of the template can be either burned off or carbonized so that it is successfully utilized as a pore switch to turn the shell of the template "on" or "off" to allow selective carbon deposition. The preferred carbon deposition process can be performed only in the inner microporous zeolite cores or just within the outer mesoporous shells, resulting in a zeolite-like ordered microporous carbon or a hollow mesoporous carbon. Full carbon deposition in the template leads to the new core-shell-structured microporous@mesoporous carbon with a nanographene-constructed framework for fast electron transport, a microporous nanocore with large surface area for high-capacity storage of lithium ions, a mesoporous shell with highly opened mesopores as a transport layer for lithium ions and electron channels to access inner cores. The ordered micropores are protected by the mesoporous shell, avoiding pore blockage as the formation of solid electrolyte interphase layers. Such a unique core-shell-structured microporous@mesoporous carbon material represents a newly established lithium ion storage model, demonstrating high reversible energy storage, excellent rate capability, and long cyclic stability. PMID:24039038

  16. OTEC gas desorption studies

    NASA Astrophysics Data System (ADS)

    Chen, F. C.; Golshani, A.

    1982-02-01

    Experiments on deaeration in packed columns and barometric intake systems, and with hydraulic air compression for open-cycle OTEC systems are reported. A gas desorption test loop consisting of water storage tanks, a vacuum system, a liquid recirculating system, an air supply, a column test section, and two barometric leg test sections was used to perform the tests. The aerated water was directed through columns filled with either ceramic Raschig rings or plastic pall rings, and the system vacuum pressure, which drives the deaeration process, was found to be dependent on water velocity and intake pipe height. The addition of a barometric intake pipe increased the deaeration effect 10%, and further tests were run with lengths of PVC pipe as potential means for noncondensibles disposal through hydraulic air compression. Using the kinetic energy from the effluent flow to condense steam in the noncondensible stream improved the system efficiency.

  17. 40 CFR 170.232 - Knowledge of labeling and site-specific information.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Knowledge of labeling and site... (CONTINUED) PESTICIDE PROGRAMS WORKER PROTECTION STANDARD Standard for Pesticide Handlers § 170.232 Knowledge of labeling and site-specific information. (a) Knowledge of labeling information. (1) The...

  18. Automated measurement of site-specific N-glycosylation occupancy with SWATH-MS.

    PubMed

    Xu, Ying; Bailey, Ulla-Maja; Schulz, Benjamin L

    2015-07-01

    Asparagine-linked glycosylation is a common post-translational modification of proteins catalyzed by oligosaccharyltransferase that is important in regulating many aspects of protein function. Analysis of protein glycosylation, including glycoproteomic measurement of the site-specific extent of glycosylation, remains challenging. Here, we developed methods combining enzymatic deglycosylation and protease digestion with SWATH-MS to enable automated measurement of site-specific occupancy at many glycosylation sites. Deglycosylation with peptide-endoglycosidase H, leaving a remnant N-acetylglucosamine on asparagines previously carrying high-mannose glycans, followed by trypsin digestion allowed robust automated measurement of occupancy at many sites. Combining deglycosylation with the more general peptide-N-glycosidase F enzyme with AspN protease digest allowed robust automated differentiation of nonglycosylated and deglycosylated forms of a given glycosylation site. Ratiometric analysis of deglycosylated peptides and the total intensities of all peptides from the corresponding proteins allowed relative quantification of site-specific glycosylation occupancy between yeast strains with various isoforms of oligosaccharyltransferase. This approach also allowed robust measurement of glycosylation sites in human salivary glycoproteins. This method for automated relative quantification of site-specific glycosylation occupancy will be a useful tool for research with model systems and clinical samples. PMID:25737293

  19. Site-specific risk factors for ray blight in Tasmanian pyrethrum fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ray blight of pyrethrum, caused by Phoma ligulicola var. inoxydablis can cause significant reductions in crop growth and pyrethrin yield. Weather and site-specific disease risk factors for ray blight have not been identified or quantified in terms of relative risk, which has limited the efficiency ...

  20. Performance evaluation of quantitative adiabatic (13)C NMR pulse sequences for site-specific isotopic measurements.

    PubMed

    Thibaudeau, Christophe; Remaud, Gérald; Silvestre, Virginie; Akoka, Serge

    2010-07-01

    (2)H/(1)H and (13)C/(12)C site-specific isotope ratios determined by NMR spectroscopy may be used to discriminate pharmaceutically active ingredients based on the synthetic process used in production. Extending the Site-specific Natural Isotope Fractionation NMR (SNIF-NMR) method to (13)C is highly beneficial for complex organic molecules when measurements of (2)H/(1)H ratios lead to poorly defined molecular fingerprints. The current NMR methodology to determine (13)C/(12)C site-specific isotope ratios suffers from poor sensitivity and long experimental times. In this work, several NMR pulse sequences based on polarization transfer were evaluated and optimized to measure precise quantitative (13)C NMR spectra within a short time. Adiabatic 180 degrees (1)H and (13)C pulses were incorporated into distortionless enhancement by polarization transfer (DEPT) and refocused insensitive nuclei enhanced by polarization transfer (INEPT) to minimize the influence of 180 degrees pulse imperfections and of off-resonance effects on the precision of the measured (13)C peak areas. The adiabatic DEPT sequence was applied to draw up a precise site-specific (13)C isotope profile of ibuprofen. A modified heteronuclear cross-polarization (HCP) experiment featuring (1)H and (13)C spin-locks with adiabatic 180 degrees pulses is also introduced. This sequence enables efficient magnetization transfer across a wide (13)C frequency range although not enough for an application in quantitative (13)C isotopic analysis. PMID:20527737

  1. Software Design for Wireless Sensor-based Site-specific Irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In-field sensor-based site-specific irrigation management is of benefit to producers for efficient water management. Integration of the decision making process with the controls is a viable option for determining when and where to irrigate, and how much water to apply. This research presents the des...

  2. Multispectral Imaging Systems for Airborne Remote Sensing to Support Site-Specific Agricultural Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Remote sensing has shown promise as a tool for site-specific management in agricultural application and production. Earth-observing satellite systems have an advantage for large-scale analysis at regional levels but are limited in spatial resolution. High-resolution satellite systems have been avail...

  3. 30 CFR 46.11 - Site-specific hazard awareness training.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Site-specific hazard awareness training. 46.11 Section 46.11 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR EDUCATION AND TRAINING TRAINING AND RETRAINING OF MINERS ENGAGED IN SHELL DREDGING OR EMPLOYED AT SAND, GRAVEL,...

  4. 30 CFR 46.11 - Site-specific hazard awareness training.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Site-specific hazard awareness training. 46.11 Section 46.11 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR EDUCATION AND TRAINING TRAINING AND RETRAINING OF MINERS ENGAGED IN SHELL DREDGING OR EMPLOYED AT SAND, GRAVEL,...

  5. 30 CFR 46.11 - Site-specific hazard awareness training.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Site-specific hazard awareness training. 46.11 Section 46.11 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR EDUCATION AND TRAINING TRAINING AND RETRAINING OF MINERS ENGAGED IN SHELL DREDGING OR EMPLOYED AT SAND, GRAVEL,...

  6. 30 CFR 46.11 - Site-specific hazard awareness training.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Site-specific hazard awareness training. 46.11 Section 46.11 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR EDUCATION AND TRAINING TRAINING AND RETRAINING OF MINERS ENGAGED IN SHELL DREDGING OR EMPLOYED AT SAND, GRAVEL,...

  7. 30 CFR 46.11 - Site-specific hazard awareness training.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Site-specific hazard awareness training. 46.11 Section 46.11 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR EDUCATION AND TRAINING TRAINING AND RETRAINING OF MINERS ENGAGED IN SHELL DREDGING OR EMPLOYED AT SAND, GRAVEL,...

  8. CRISPR Outsourcing: Commissioning IHF for Site-Specific Integration of Foreign DNA at the CRISPR Array.

    PubMed

    Wei, Yunzhou; Terns, Michael P

    2016-06-16

    In this issue of Molecular Cell, Nuñez et al. (2016) report that site-specific integration of foreign DNA into CRISPR loci by the Cas1-Cas2 integrase complex is promoted by a host factor, IHF (integration host factor), that binds and bends CRISPR leader DNA. PMID:27315553

  9. Is it enough to have one ECa map for the site-specific management delineation?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The soil apparent electrical conductivity (ECa) has been used to map soil spatial variability and to relate it to the variability of various soil properties thus delineating zones of site-specific management. Most often, a single ECa survey is done and the generated ECa map is considered to infer t...

  10. 76 FR 1415 - Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-10

    ... Ridge Reservation. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat. 770) requires that... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Oak Ridge Reservation AGENCY: Department of...

  11. Site-specific management of soil pH and nutrients in blueberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific management of soil pH and fertilizers is one of the most promising strategies in precision agriculture and is potentially applicable to many horticultural crops, including blueberry. Unlike most fruit crops, blueberry is adapted to low soil pH conditions in the range of 4-5.5 and has ...

  12. Site-specific management of pH-induced iron chlorosis of maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted over nine site/years in Nebraska, USA between 2004 and 2005 to evaluate the potential to predict chlorosis-prone areas within fields which are relatively stable in space and time. The study also investigated the potential benefits of site-specific cultivar management according ...

  13. Environmental Restoration Site-Specific Plan for the Portsmouth Gaseous Diffusion Plant, FY 93

    SciTech Connect

    Not Available

    1993-01-15

    The purpose of this Site-Specific Plan (SSP) is to describe past, present, and future activities undertaken to implement Environmental Restoration and Waste Management goals at the Portsmouth Gaseous Diffusion Plant (PORTS). The SSP is presented in sections emphasizing Environmental Restoration description of activities, resources, and milestones.

  14. Use of an Unmanned Aerial system for Site-Specific Management of Cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Remote sensing is a promising technology for site-specific management of in situ crop stress. In particular, compared to reflective regions of the spectrum, thermal infrared imagery is a more direct metric of crop response. However, in practice the expense associated with acquiring thermal infrare...

  15. 76 FR 55369 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-07

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463... Flemming, Office of External Affairs, Department of Energy, Savannah River Operations Office, P.O. Box...

  16. 76 FR 25682 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-05

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463... of External Affairs, Department of Energy, Savannah River Operations Office, P.O. Box A, Aiken,...

  17. 78 FR 14088 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-04

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act requires that... Affairs, Department of Energy, Savannah River Operations Office, P.O. Box A, Aiken, SC 29802; Phone:...

  18. 76 FR 65706 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-24

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463... Flemming, Office of External Affairs, Department of Energy, Savannah River Operations Office, P.O. Box...

  19. 76 FR 11772 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-03

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463... of External Affairs, Department of Energy, Savannah River Operations Office, P.O. Box A, Aiken,...

  20. 78 FR 26005 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-03

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463...: Gerri Flemming, Office of External Affairs, Department of Energy, Savannah River Operations Office,...

  1. 78 FR 40130 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-03

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. No. 92... CONTACT: Gerri Flemming, Office of External Affairs, Department of Energy, Savannah River...

  2. 75 FR 65466 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-25

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463... Flemming, Office of External Affairs, Department of Energy, Savannah River Operations Office, P.O. Box...

  3. 75 FR 39007 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ...This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat. 770) requires that public notice of this meeting be announced in the Federal...

  4. 75 FR 24684 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463... of External Affairs, Department of Energy, Savannah River Operations Office, P.O. Box A, Aiken,...

  5. 77 FR 60688 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-04

    ...This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat. 770) requires that public notice of this meeting be announced in the Federal...

  6. 75 FR 9885 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463... External Affairs, Department of Energy, Savannah River Operations Office, P.O. Box A, Aiken, SC...

  7. 75 FR 82001 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act requires that... Affairs, Department of Energy, Savannah River Operations Office, P.O. Box A, Aiken, SC 29802; Phone:...

  8. Use of GIS-based site-specific nitrogen management for improving energy efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen (N) is a significant energy component of in support of crop production but it can be highly variable within fields. To our knowledge, no efforts have been made to employ GIS-based site-specific N management (SSNM) to assess and improve energy costs and efficiency. We examine recent SSNM ca...

  9. 77 FR 13104 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-05

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463... of External Affairs, Department of Energy, Savannah River Operations Office, P.O. Box A, Aiken,...

  10. 78 FR 54461 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-04

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463... CONTACT: Gerri Flemming, Office of External Affairs, Department of Energy, Savannah River...

  11. 75 FR 57462 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-21

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. No. 92...: Gerri Flemming, Office of External Affairs, Department of Energy, Savannah River Operations Office,...

  12. 78 FR 65979 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-04

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463..., Office of External Affairs, Department of Energy, Savannah River Operations Office, P.O. Box A, Aiken,...

  13. 77 FR 39235 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-02

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463...: Gerri Flemming, Office of External Affairs, Department of Energy, Savannah River Operations Office,...

  14. 76 FR 81487 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-28

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463... Flemming, Office of External Affairs, Department of Energy, Savannah River Operations Office, P.O. Box...

  15. 75 FR 983 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-07

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463... Smith, Office of External Affairs, Department of Energy, Savannah River Operations Office, P.O. Box...

  16. 77 FR 24695 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-25

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. . 92... Flemming, Office of External Affairs, Department of Energy, Savannah River Operations Office, P.O. Box...

  17. 77 FR 53193 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-31

    ... Environmental Management Site-Specific Advisory Board, Savannah River Site AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463... CONTACT: Gerri Flemming, Office of External Affairs, Department of Energy, Savannah River...

  18. Using site-specific soil samples as a substitution for improved hydrological and nonpoint source predictions.

    PubMed

    Chen, Lei; Wang, Guobo; Zhong, Yucen; Zhao, Xin; Shen, Zhenyao

    2016-08-01

    Soil databases are one of the most important inputs for watershed models, and the quality of soil properties affects how well a model performs. The objectives of this study were to (1) quantify the sensitivity of model outputs to soil properties and to (2) use site-specific soil properties as a substitution for more accurate hydrological and nonpoint source (H/NPS) predictions. Soil samples were collected from a typical mountainous watershed in China, and the impacts of soil sample parameters on H/NPS predictions were quantified using the Soil and Water Assessment Tool (SWAT). The most sensitive parameters related to predicting flow, sediment, and total phosphorus (TP) mainly were the soil hydrological, the channel erosion processes, and the initial soil chemical environment, respectively. When the site-specific soil properties were used, the uncertainties (coefficient of variation) related to predicting the hydrology, sediment and TP decreased by 75∼80 %, 75∼84 %, and 46∼61 %, respectively. Based on changes in the Nash-Sutcliff coefficient, the model performance improved by 4.9 and 19.45 % for the hydrological and sediment model, accordingly. However, site-specific soil properties did not contribute to better TP predictions because of the high spatial variability of the soil P concentrations across the large watershed. Thus, although site-specific soil samples can be used to obtain more accurate H/NPS predictions, more sampling sites are required to apply this method in large watersheds. PMID:27146539

  19. 40 CFR 258.62 - Approval of site-specific flexibility requests in Indian country.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Approval of site-specific flexibility requests in Indian country. (a) Lake County Municipal Landfill final cover requirements. Paragraph (a) of this section applies to the Lake County Landfill, a municipal solid waste landfill owned and operated by Lake County on the Confederated Salish and Kootenai...

  20. 40 CFR 258.62 - Approval of site-specific flexibility requests in Indian country.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Approval of site-specific flexibility requests in Indian country. (a) Lake County Municipal Landfill final cover requirements. Paragraph (a) of this section applies to the Lake County Landfill, a municipal solid waste landfill owned and operated by Lake County on the Confederated Salish and Kootenai...

  1. 78 FR 63172 - Environmental Management Site-Specific Advisory Board, Paducah; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ...This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Paducah. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat. 770) requires that public notice of this meeting be announced in the Federal...

  2. 40 CFR 60.3019 - What site-specific documentation is required?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... procedures. (8) The waste management plan required under §§ 60.3010 through 60.3012. (9) Procedures for... Times for Other Solid Waste Incineration Units That Commenced Construction On or Before December 9, 2004 Model Rule-Operator Training and Qualification § 60.3019 What site-specific documentation is...

  3. CAN SITE-SPECIFIC TRENDS BE EXTRAPOLATED TO A REGION? AN ACIDIFICATION EXAMPLE FOR THE NORTHEAST

    EPA Science Inventory

    In the absence of true regional data on changes in the acid/base status of lakes in the northeastern United States, we explore the possibility of using site-specific trends information from a judgment sample of lakes to assess the efficacy of the Clean Air Act Amendments. A meta-...

  4. 76 FR 17636 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-30

    ... Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy (DOE). ACTION...-Specific Advisory Board (EM SSAB), Paducah. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat..., April 21, 2011; 6 p.m. ADDRESSES: Barkley Centre, 111 Memorial Drive, Paducah, Kentucky 42001....

  5. 76 FR 31599 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-01

    ... Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy (DOE). ACTION...-Specific Advisory Board (EM SSAB), Paducah. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat..., June 23, 2011, 6 p.m. ADDRESSES: Barkley Centre, 111 Memorial Drive, Paducah, Kentucky 42001....

  6. 76 FR 11228 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-01

    ... Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy (DOE). ACTION...-Specific Advisory Board (EM SSAB), Paducah. The Federal Advisory Committee Act (Pub. L. No. 92-463, 86 Stat..., March 17, 2011; 6 p.m. ADDRESSES: Barkley Centre, 111 Memorial Drive, Paducah, Kentucky 42001....

  7. 75 FR 37782 - Environmental Management Site-Specific Advisory Board, Paducah, KY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-30

    ... Environmental Management Site-Specific Advisory Board, Paducah, KY AGENCY: Department of Energy (DOE). ACTION...-Specific Advisory Board (EM SSAB), Paducah. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat..., July 15, 2010, 6 p.m. ADDRESSES: Barkley Centre, 111 Memorial Drive, Paducah, Kentucky 42001....

  8. 76 FR 49757 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-11

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... Board is to make recommendations to DOE-EM and site management in the areas of environmental...

  9. 77 FR 75626 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-21

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... Board is to make recommendations to DOE-EM and site management in the areas of environmental...

  10. 76 FR 21878 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-19

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... Board is to make recommendations to DOE-EM and site management in the areas of environmental...

  11. Comparison of site-specific and conventional uniform irrigation management on potatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-Specific Irrigation Management (SSIM) can be defined as irrigation management (depth, timing) based on crop need to defined sub-areas of a field referred to as management zones. Implementation of SSIM will require additional irrigation system hardware, labor and information on soil and/or plant...

  12. 75 FR 27999 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-19

    ...This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Hanford. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat. 770) requires that public notice of this meeting be announced in the Federal...

  13. The parA resolvase performs site-specific genomic excision in Arabidopsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have designed a site-specific excision detection system in Arabidopsis to study the in planta activity of the small serine recombinase ParA. Using a transient expression assay as well as stable transgenic plant lines, we show that the ParA recombinase is catalytically active and capable of perfo...

  14. Semiparametric Geographically Weighted Response Curves with Application to Site Specific Agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lack of basic knowledge about spatial and treatment varying crop response to irrigation hinders irrigation management and economic analysis for site-specific agriculture. One model that has been postulated for relating crop-specific economic quantities to irrigation is a quadratic response curve of...

  15. Selective pressures to maintain attachment site specificity of integrative and conjugative elements.

    PubMed

    Menard, Kayla L; Grossman, Alan D

    2013-01-01

    Integrative and conjugative elements (ICEs) are widespread mobile genetic elements that are usually found integrated in bacterial chromosomes. They are important agents of evolution and contribute to the acquisition of new traits, including antibiotic resistances. ICEs can excise from the chromosome and transfer to recipients by conjugation. Many ICEs are site-specific in that they integrate preferentially into a primary attachment site in the bacterial genome. Site-specific ICEs can also integrate into secondary locations, particularly if the primary site is absent. However, little is known about the consequences of integration of ICEs into alternative attachment sites or what drives the apparent maintenance and prevalence of the many ICEs that use a single attachment site. Using ICEBs1, a site-specific ICE from Bacillus subtilis that integrates into a tRNA gene, we found that integration into secondary sites was detrimental to both ICEBs1 and the host cell. Excision of ICEBs1 from secondary sites was impaired either partially or completely, limiting the spread of ICEBs1. Furthermore, induction of ICEBs1 gene expression caused a substantial drop in proliferation and cell viability within three hours. This drop was dependent on rolling circle replication of ICEBs1 that was unable to excise from the chromosome. Together, these detrimental effects provide selective pressure against the survival and dissemination of ICEs that have integrated into alternative sites and may explain the maintenance of site-specific integration for many ICEs. PMID:23874222

  16. Site-specific mouth rinsing can improve oral odor by altering bacterial counts

    PubMed Central

    Alqumber, Mohammed A.; Arafa, Khaled A.

    2014-01-01

    Objectives: To determine whether site-specific mouth rinsing with oral disinfectants can improve oral odor beyond the traditional panoral mouth disinfection with mouth rinses by targeting specifically oral malodor implicated anaerobic bacteria Methods: Twenty healthy fasting subjects volunteered for a blinded prospective, descriptive correlational crossover cross-section clinical trial conducted during the month of Ramadan between July and August 2013 in Albaha province in Saudi Arabia involving the application of Listerine® Cool Mint® mouth rinse by either the traditional panoral rinsing method, or a site-specific disinfection method targeting the subgingival and supragingival plaque and the posterior third of the tongue dorsum, while avoiding the remaining locations within the oral cavity. The viable anaerobic and aerobic bacterial counts, volatile sulfur compounds (VSCs) levels, organoleptic assessment of oral odor, and the tongue-coating index were compared at baseline, one, 5, and 9 hours after the treatment. Results: The site-specific disinfection method reduced the VSCs and anaerobic bacterial loads while keeping the aerobic bacterial numbers higher than the traditional panoral rinsing method. Conclusion: Site-specific disinfection can more effectively maintain a healthy oral cavity by predominantly disinfecting the niches of anaerobic bacteria within the oral cavity. PMID:25399224

  17. Appreciating "Thirdspace": An Alternative Way of Viewing and Valuing Site-Specific Dance Performance

    ERIC Educational Resources Information Center

    Munjee, Tara

    2014-01-01

    Site-specific dance performance involves the presentation of choreography in connection with a site. The context of the site combined with a viewer's personal history, beliefs, and identity impact the reading and appreciation of the performance. Although both stage and site dance performance valuing elicit multiple interpretations of artistic…

  18. 77 FR 66962 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-08

    ... Environmental Impact Statement Briefing/Update 3. Nye County Drilling Presentation 4. Industrial Sites-Closing... above. Written statements may be filed with the Board either before or after the meeting. Individuals... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice...

  19. 76 FR 21878 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-19

    .... Greater-Than-Class-C Draft Environmental Impact Statement (EIS) Committee Update. 3. Site-Wide EIS Update... Rupp at least seven days in advance of the meeting at the phone number listed above. Written statements... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice...

  20. 76 FR 29229 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-20

    ... Agenda: 1. Recommendation Development: Greater-Than-Class C Draft Environmental Impact Statement (EIS) 2... number listed above. Written statements may be filed with the Board either before or after the meeting... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice...

  1. 76 FR 59393 - Environmental Management Site-Specific Advisory Board, Nevada

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-26

    ... Impact Statement Public Participation: The EM SSAB, Nevada, welcomes the attendance of the public at its... least seven days in advance of the meeting at the phone number listed above. Written statements may be... Environmental Management Site-Specific Advisory Board, Nevada AGENCY: Department of Energy. ACTION: Notice...

  2. 75 FR 11872 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-12

    ..., Idaho National Laboratory to be held on March 16, 2010 75 FR 9590. In that notice, the meeting address... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Idaho National Laboratory AGENCY: Department of...

  3. Evaluation of closed-loop site-specific irrigation with wireless sensor network

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Automated site-specific sprinkler irrigation system can save water and maximize productivity, but implementing automated irrigation is challenging in system integration and decision making. A controllable irrigation system was integrated into a closed-loop control with a distributed wireless in-fiel...

  4. Design, development and evaluation of a tree planting-site-specific fumigant applicator

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this research was to use recent advances in the global positioning system (GPS) and computer technology to apply just the right amount of fumigant where it is most needed (i.e., tree-planting-site-specific application) to decrease the incidence of replant disease, and achieve the environ...

  5. 76 FR 78909 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-20

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L. 92-463..., Pojoaque, New Mexico 87506. FOR FURTHER INFORMATION CONTACT: Menice Santistevan, Northern New...

  6. 77 FR 66599 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-06

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L. 92-463... Gold Road, Pojoaque, NM 87506. FOR FURTHER INFORMATION CONTACT: Menice Santistevan, Northern New...

  7. 77 FR 53192 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-31

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L. 92-463... 2013 Work Priorities, New Mexico Environment Department (NMED) and DOE 4:00 p.m. Items from...

  8. 75 FR 9886 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L. 92-463..., Santa Fe, New Mexico 87501. FOR FURTHER INFORMATION CONTACT: Menice Santistevan, Northern New...

  9. 75 FR 82003 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L. 92-463..., New Mexico. FOR FURTHER INFORMATION CONTACT: Menice Santistevan, Northern New Mexico...

  10. 78 FR 49739 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-15

    ...This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat. 770) requires that public notice of this meeting be announced in the Federal...

  11. 78 FR 10612 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-14

    ...This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat. 770) requires that public notice of this meeting be announced in the Federal...

  12. 75 FR 35446 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-22

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L. No. 92... Drive, Los Alamos, New Mexico 87544. FOR FURTHER INFORMATION CONTACT: Menice Santistevan, Northern...

  13. 77 FR 12044 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-28

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L. 92-463... Road NE., Albuquerque, New Mexico 87109. FOR FURTHER INFORMATION CONTACT: Menice Santistevan,...

  14. 76 FR 80915 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-27

    ... Environmental Management Site-Specific Advisory Board, Northern New Mexico AGENCY: Department of Energy. ACTION...-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal Advisory Committee Act (Pub. L. 92-463... Road, Santa Fe, New Mexico 87506. FOR FURTHER INFORMATION CONTACT: Menice Santistevan, Northern...

  15. Use of GIS-based Site-specific Nitrogen Management for Improving Energy Efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To our knowledge, geographical information system (GIS)-based site-specific nitrogen management (SSNM) techniques have not been used to assess agricultural energy costs and efficiency. This chapter uses SSNM case studies for corn (Zea mays L.) grown in Missouri and cotton (Gossypium hirsutum L.) gro...

  16. Beyond Patch Spraying: Site-specific Weed Mmanagement With Multiple Herbicides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific weed management can include both limiting herbicide to areas of the field where weed pressure is above the economic threshold (patch spraying) and varying the choice of herbicide for most cost-effective weed control of local populations. The benefits of patch spraying with multiple, po...

  17. Development of Unmanned Aerial Vehicles for Site-Specific Crop Production Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Unmanned Aerial Vehicles (UAV) have been developed and applied to support the practice of precision agriculture. Compared to piloted aircrafts, an Unmanned Aerial Vehicle can focus on much smaller crop fields with much lower flight altitude than regular airplanes to perform site-specific management ...

  18. Evaluation of water-effect ratio methodology for establishing site-specific water quality criteria

    SciTech Connect

    Welsh, P.G.; Lipton, J.; Chapman, G.A.

    2000-06-01

    One approach outlined by the US Environmental Protection Agency (US EPA) for derivation of site-specific water quality criteria for metals in natural surface waters involves the development of water-effect ratios (WERs). This approach entails multiplying national water quality criteria by an experimentally derived WER, where the WER is defined as the ratio of the toxicity of the metal in the site water to the toxicity of the same metal in standard laboratory water. The authors discuss technical issues associated with test methods described in the US EPA WER guidance documents that may lead to inappropriate WERs. Critical issues include accounting for differences in calcium and magnesium concentrations (Ca:Mg ratios), alkalinity, and pH between site and laboratory waters; ensuring appropriate fish acclimation; and accounting for interspecies variability, multiple metals interactions, end-point variability, and temporal and spatial variability in the derivation of the WER. Failure to address these issues may have the unintended effect of deriving site-specific water quality criteria that are underprotective of aquatic life. The authors recommend that WER testing and future regulatory guidance for derivation of site-specific water quality criteria incorporate consideration of these potential confounding variables so that site-specific criteria can be established with greater confidence.

  19. 78 FR 716 - Environmental Management Site-Specific Advisory Board, Savannah River Site

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-04

    ...This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Savannah River Site. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat. 770) requires that public notice of this meeting be announced in the Federal...

  20. Germinal transmission of site-specific excised genomic DNA by the bacterial ParA resolvase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genome engineering is an essential tool in research and product development. Behind some of the recent advances in plant gene transfer is the development of site-specific recombination systems that enable the precise manipulation of DNA, e.g. the deletion, integration or translocation of DNA. DNA ...

  1. Integrated decision support, sensor networks and adaptive control for wireless site-specific sprinkler irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of site-specific sprinkler irrigation water management systems will be a major factor in future efforts to improve the various efficiencies of water-use and to support a sustainable irrigated environment. The challenge is to develop fully integrated management systems with supporting...

  2. Integrated Decision Support, Sensor Networks and Adaptive Control for Wireless Site-specific Sprinkler Irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of site-specific sprinkler irrigation water management systems will be a major factor in future efforts to improve the various efficiencies of water-use and to support a sustainable irrigated environment. The challenge is to develop fully integrated management systems with supporting...

  3. Hellsgate Big Game Winter Range Wildlife Mitigation Site Specific Management Plan for the Hellsgate Project.

    SciTech Connect

    Berger, Matthew T.; Judd, Steven L.

    1999-01-01

    This report contains a detailed site-specific management plan for the Hellsgate Winter Range Wildlife Mitigation Project. The report provides background information about the mitigation process, the review process, mitigation acquisitions, Habitat Evaluation Procedures (HEP) and mitigation crediting, current habitat conditions, desired future habitat conditions, restoration/enhancements efforts and maps.

  4. SITE-SPECIFIC PROTOCOL FOR MEASURING SOIL RADON POTENTIALS FOR FLORIDA HOUSES

    EPA Science Inventory

    The report describes a protocol for site-specific measurement of radon potentials for Florida houses that is consistent with existing residential radon protection maps. The protocol gives further guidance on the possible need for radon-protective house construction features. In a...

  5. 76 FR 14386 - Environmental Management Site-Specific Advisory Board, Hanford

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-16

    ...This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Hanford. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat. 770) requires that public notice of this meeting be announced in the Federal...

  6. 78 FR 56871 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-16

    ...This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Portsmouth. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat. 770) requires that public notice of this meeting be announced in the Federal...

  7. 78 FR 69657 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-20

    ...This notice announces a meeting of the Environmental Management Site-Specific Advisory Board (EM SSAB), Portsmouth. The Federal Advisory Committee Act (Pub. L. 92-463, 86 Stat. 770) requires that public notice of this meeting be announced in the Federal...

  8. Site-Specific Recombination Systems for the Genetic Manipulation of Eukaryotic Genomes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific recombination systems, such as the bacteriophage Cre-lox and yeast FLP-FRT systems, have become valuable tools for the rearrangement of DNA in higher eukaryotes. As a first step to expanding the repertoire of recombination tools, we screened recombination systems derived from the reso...

  9. 75 FR 61711 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-06

    ... Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy (DOE). ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... management in the areas of environmental restoration, waste management and related activities....

  10. 75 FR 51026 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-18

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... Board is to make recommendations to DOE-EM and site management in the areas of environmental...

  11. 76 FR 80355 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-23

    ... Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy (DOE). ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... and site management in the areas of environmental restoration, waste management, and...

  12. 78 FR 16260 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-14

    ... Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy (DOE). ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... management in the areas of environmental restoration, waste management and related activities....

  13. 75 FR 66074 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-27

    ... Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy (DOE). ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... management in the areas of environmental restoration, waste management and related activities....

  14. 77 FR 37390 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-21

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... Board is to make recommendations to DOE-EM and site management in the areas of environmental...

  15. 77 FR 63300 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-16

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy (DOE). ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... Board is to make recommendations to DOE-EM and site management in the areas of environmental...

  16. 76 FR 48148 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-08

    ... Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy (DOE). ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... management in the areas of environmental restoration, waste management and related activities....

  17. 75 FR 24686 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ... Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy (DOE). ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... management in the areas of environmental restoration, waste management and related activities....

  18. 77 FR 43583 - Environmental Management Site-Specific Advisory Board, Paducah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-25

    ... Environmental Management Site-Specific Advisory Board, Paducah AGENCY: Department of Energy (DOE). ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... management in the areas of environmental restoration, waste management and related activities....

  19. 76 FR 36100 - Environmental Management Site-Specific Advisory Board, Portsmouth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-21

    ... Environmental Management Site-Specific Advisory Board, Portsmouth AGENCY: Department of Energy. DOE. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Environmental Management Site... Board is to make recommendations to DOE-EM and site management in the areas of environmental...

  20. 76 FR 62054 - Environmental Management Site-Specific Advisory Board Chairs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-06

    ... Environmental Management Site-Specific Advisory Board Chairs AGENCY: Department of Energy. ACTION: Notice of open teleconference. SUMMARY: This notice announces a teleconference of the Environmental Management... make recommendations to DOE-EM and site management in the areas of environmental restoration,...