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Sample records for collision-induced dissociation mass

  1. Collision-induced dissociation with Fourier transform mass spectrometry

    International Nuclear Information System (INIS)

    Cody, R.B.; Burnier, R.C.; Freiser, B.S.

    1982-01-01

    Collision-induced dissociations (CID) is demonstrated on a number of primary and secondary ions using a Nicolet prototype Fourier transform mass spectrometer (FT-MS). Like the triple quadrupole technique, CID using FT-MS is a relatively low energy and efficient process. The ability to study a wide range of ion-molecule reaction products is exemplified by results on proton-bound dimers and transition metal containing ionic species. Variation of collision energy by varying the RF irradiation level can provide information about product distributions as a function of energy as well as yield ion structural information. Like the triple quadrupole technique, no slits are employed and virtually all of the fragment ions formed by the CID process may be detected. Unlike all previous mass spectrometric techniques for studying CID, a tandem instrument is not required, and different experiments are performed by making software modifications rather than hardware modifications

  2. Collision-Induced Dissociation Mass Spectrometry: A Powerful Tool for Natural Product Structure Elucidation.

    Science.gov (United States)

    Johnson, Andrew R; Carlson, Erin E

    2015-11-03

    Mass spectrometry is a powerful tool in natural product structure elucidation, but our ability to directly correlate fragmentation spectra to these structures lags far behind similar efforts in peptide sequencing and proteomics. Often, manual data interpretation is required and our knowledge of the expected fragmentation patterns for many scaffolds is limited, further complicating analysis. Here, we summarize advances in natural product structure elucidation based upon the application of collision induced dissociation fragmentation mechanisms.

  3. A high-resolution tandem mass spectrometer for the collision-induced dissociation of large molecule ions

    International Nuclear Information System (INIS)

    Ouwerkerk, C.E.D.

    1988-01-01

    Instrumental development in the field of tandem mass spectrometry is described in order to use the technique for the analysis of large organic molecules. Experiments are also described in which the process of collision-induced dissociation (CID) is investigated. The fragmentation pattern of CH 4 + has been measured for three different target gases He, Ar and Xe. From these measurements fragmentation cross sections are calculated. 192 refs.; 47 figs.; 6 tabs

  4. Collision induced dissociation of protonated N-nitrosodimethylamine by ion trap mass spectrometry: Ultimate carcinogens in gas phase

    Science.gov (United States)

    Kulikova, Natalia; Baker, Michael; Gabryelski, Wojciech

    2009-12-01

    Collision induced dissociation of protonated N-nitrosodimethylamine (NDMA) and isotopically labeled N-nitrosodimethyl-d6-amine (NDMA-d6) was investigated by sequential ion trap mass spectrometry to establish mechanisms of gas phase reactions leading to intriguing products of this potent carcinogen. The fragmentation of (NDMA + H+) occurs via two dissociation pathways. In the alkylation pathway, homolytic cleavage of the N-O bond of N-dimethyl, N'-hydroxydiazenium ion generates N-dimethyldiazenium distonic ion which reacts further by a CH3 radical loss to form methanediazonium ion. Both methanediazonium ion and its precursor are involved in ion/molecule reactions. Methanediazonium ion showed to be capable of methylating water and methanol molecules in the gas phase of the ion trap and N-dimethyldiazenium distonic ion showed to abstract a hydrogen atom from a solvent molecule. In the denitrosation pathway, a tautomerization of N-dimethyl, N'-hydroxydiazenium ion to N-nitrosodimethylammonium intermediate ion results in radical cleavage of the N-N bond of the intermediate ion to form N-dimethylaminium radical cation which reacts further through [alpha]-cleavage to generate N-methylmethylenimmonium ion. Although the reactions of NDMA in the gas phase are different to those for enzymatic conversion of NDMA in biological systems, each activation method generates the same products. We will show that collision induced dissociation of N-nitrosodiethylamine (NDEA) and N-nitrosodipropylamine (NDPA) is also a feasible approach to gain information on formation, stability, and reactivity of alkylating agents originating from NDEA and NDPA. Investigating such biologically relevant, but highly reactive intermediates in the condensed phase is hampered by the short life-times of these transient species.

  5. Fragmentation study of iridoid glucosides through positive and negative electrospray ionization, collision-induced dissociation and tandem mass spectrometry.

    Science.gov (United States)

    Es-Safi, Nour-Eddine; Kerhoas, Lucien; Ducrot, Paul-Henri

    2007-01-01

    Mass spectrometric methodology based on the combined use of positive and negative electrospray ionization, collision-induced dissociation (CID) and tandem mass spectrometry (MS/MS) has been applied to the mass spectral study of a series of six naturally occurring iridoids through in-source fragmentation of the protonated [M+H]+, deprotonated [M--H]- and sodiated [M+Na]+ ions. This led to the unambiguous determination of the molecular masses of the studied compounds and allowed CID spectra of the molecular ions to be obtained. Valuable structural information regarding the nature of both the glycoside and the aglycone moiety was thus obtained. Glycosidic cleavage and ring cleavages of both aglycone and sugar moieties were the major fragmentation pathways observed during CID, where the losses of small molecules, the cinnamoyl and the cinnamate parts were also observed. The formation of the ionized aglycones, sugars and their product ions was thus obtained giving information on their basic skeleton. The protonated, i.e. [M+H]+ and deprotonated [M--H]-, ions were found to fragment mainly by glycosidic cleavages. MS/MS spectra of the [M+Na]+ ions gave complementary information for the structural characterization of the studied compounds. Unlike the dissociation of protonated molecular ions, that of sodiated molecules also provided sodiated sugar fragments where the C0+ fragment corresponding to the glucose ion was obtained as base peak for all the studied compounds. Copyright (c) 2007 John Wiley & Sons, Ltd.

  6. In-source collision induced dissociation of inorganic explosives for mass spectrometric signature detection and chemical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Forbes, Thomas P., E-mail: thomas.forbes@nist.gov; Sisco, Edward

    2015-09-10

    The trace detection, bulk quantification, and chemical imaging of inorganic explosives and components was demonstrated utilizing in-source collision induced dissociation (CID) coupled with laser desorption/ionization mass spectrometry (LDI-MS). The incorporation of in-source CID provided direct control over the extent of adduct and cluster fragmentation as well as organic noise reduction for the enhanced detection of both the elemental and molecular ion signatures of fuel-oxidizer mixtures and other inorganic components of explosive devices. Investigation of oxidizer molecular anions, specifically, nitrates, chlorates, and perchlorates, identified that the optimal in-source CID existed at the transition between fragmentation of the ionic salt bonds and molecular anion bonds. The chemical imaging of oxidizer particles from latent fingerprints was demonstrated, including both cation and anion components in positive and negative mode mass spectrometry, respectively. This investigation demonstrated LDI-MS with in-source CID as a versatile tool for security fields, as well as environmental monitoring and nuclear safeguards, facilitating the detection of elemental and molecular inorganic compounds at nanogram levels. - Highlights: • In-source CID enhanced detection of elemental inorganics up to 1000-fold. • In-source CID optimization of polyatomic oxidizers enhanced detection up to 100-fold. • Optimal CID identified at transition from breaking ionic salt to molecular anion bonds. • Trace detection of inorganic explosives at nanogram levels was demonstrated. • Oxidizer particles were chemically imaged directly from latent fingerprints.

  7. Development of a collision induced dissociation ion cyclotron resonance spectrometer

    International Nuclear Information System (INIS)

    Fan, Y.N.

    1982-01-01

    A transient analysis ion cyclotron resonance spectrometer is developed to investigate the phenomena of collision induced dissociation. The Fourier transform method and the modified maximum entropy spectral analysis or covariance least square method are implemented in measuring the mass spectrum of the ion ensemble. The Fourier transform method can be used in quantitative analysis while the maximum entropy method as developed here is useful for qualitative analysis only. The cyclotron resonance frequency, relaxation time constant, and the relative ion population are observable from the Fourier transform spectrum. These parameters are very important in investigating collision induced dissociation process and other topics in gas phase chemistry. The ion cyclotron resonance spectrometer is not only developed to study fragments and their abundance from a parent ion, but also to determine the threshold energy and reaction cross section in the collision induced dissociation process. When hard sphere model is used in the ion-molecule collision, the radius of acetone ion measured from the reactive cross section is 2.2 angstrom which is very close to the physical dimension of acetone. The threshold energy for acetone ion in collision induced dissociation process is 1.8 eV which is similar to the result obtained by the angle-resolved mass spectrometer

  8. Gas chromatography/chemical ionization triple quadrupole mass spectrometry analysis of anabolic steroids: ionization and collision-induced dissociation behavior.

    Science.gov (United States)

    Polet, Michael; Van Gansbeke, Wim; Van Eenoo, Peter; Deventer, Koen

    2016-02-28

    The detection of new anabolic steroid metabolites and new designer steroids is a challenging task in doping analysis. Switching from electron ionization gas chromatography triple quadrupole mass spectrometry (GC/EI-MS/MS) to chemical ionization (CI) has proven to be an efficient way to increase the sensitivity of GC/MS/MS analyses and facilitate the detection of anabolic steroids. CI also extends the possibilities of GC/MS/MS analyses as the molecular ion is retained in its protonated form due to the softer ionization. In EI it can be difficult to find previously unknown but expected metabolites due to the low abundance or absence of the molecular ion and the extensive (and to a large extent unpredictable) fragmentation. The main aim of this work was to study the CI and collision-induced dissociation (CID) behavior of a large number of anabolic androgenic steroids (AAS) as their trimethylsilyl derivatives in order to determine correlations between structures and CID fragmentation. Clarification of these correlations is needed for the elucidation of structures of unknown steroids and new metabolites. The ionization and CID behavior of 65 AAS have been studied using GC/CI-MS/MS with ammonia as the reagent gas. Glucuronidated AAS reference standards were first hydrolyzed to obtain their free forms. Afterwards, all the standards were derivatized to their trimethylsilyl forms. Full scan and product ion scan analyses were used to examine the ionization and CID behavior. Full scan and product ion scan analyses revealed clear correlations between AAS structure and the obtained mass spectra. These correlations were confirmed by analysis of multiple hydroxylated, methylated, chlorinated and deuterated analogs. AAS have been divided into three groups according to their ionization behavior and into seven groups according to their CID behavior. Correlations between fragmentation and structure were revealed and fragmentation pathways were postulated. Copyright © 2016 John Wiley

  9. Collision-induced dissociation of aflatoxins.

    Science.gov (United States)

    Tóth, Katalin; Nagy, Lajos; Mándi, Attila; Kuki, Ákos; Mézes, Miklós; Zsuga, Miklós; Kéki, Sándor

    2013-02-28

    The aflatoxin mycotoxins are particularly hazardous to health when present in food. Therefore, from an analytical point of view, knowledge of their mass spectrometric properties is essential. The aim of the present study was to describe the collision-induced dissociation behavior of the four most common aflatoxins: B1, B2, G1 and G2. Protonated aflatoxins were produced using atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) combined with high-performance liquid chromatography (HPLC). For the tandem mass spectrometry (MS/MS) experiments nitrogen was used as the collision gas and the collision energies were varied in the range of 9-44 eV (in the laboratory frame). The major APCI-MS/MS fragmentations of protonated aflatoxins occurred at 30 eV collision energy. The main fragmentation channels were found to be the losses of a series of carbon monoxide molecules and loss of a methyl radical, leading to the formation of radical-type product ions. In addition, if the aflatoxin molecule contained an ether- or lactone-oxygen atom linked to a saturated carbon atom, loss of a water molecule was observed from the [M + H](+) ion, especially in the case of aflatoxins G1 and G2. A relatively small modification in the structure of aflatoxins dramatically altered the fragmentation pathways and this was particularly true for aflatoxins B1 and B2. Due to the presence of a C = C double bond connected to the ether group in aflatoxin B1 no elimination of water was observed but, instead, formation of radical-type product ions occurred. Fragmentation of protonated aflatoxin B1 yielded the most abundant radical-type cations. Copyright © 2013 John Wiley & Sons, Ltd.

  10. Collision-induced dissociation of diatomic ions

    International Nuclear Information System (INIS)

    Los, J.; Govers, T.R.

    1978-01-01

    An attempt is made to illustrate how mass spectrometric studies of dissociation in diatomic molecular ions can provide information on the dynamics of these collisions and on the predissociative states involved. Restriction is made to primary beam energies of the order of at least keV. The review covers the dynamics of dissociation, experimental techniques, direct dissociation in heavy-particle collisions, and translational spectroscopy. 120 references

  11. Implementation of dipolar direct current (DDC) collision-induced dissociation in storage and transmission modes on a quadrupole/time-of-flight tandem mass spectrometer.

    Science.gov (United States)

    Webb, Ian K; Londry, Frank A; McLuckey, Scott A

    2011-09-15

    Means for effecting dipolar direct current collision-induced dissociation (DDC CID) on a quadrupole/time-of-flight in a mass spectrometer have been implemented for the broadband dissociation of a wide range of analyte ions. The DDC fragmentation method in electrodynamic storage and transmission devices provides a means for inducing fragmentation of ions over a large mass-to-charge range simultaneously. It can be effected within an ion storage step in a quadrupole collision cell that is operated as a linear ion trap or as ions are continuously transmitted through the collision cell. A DDC potential is applied across one pair of rods in the quadrupole collision cell of a QqTOF hybrid mass spectrometer to effect fragmentation. In this study, ions derived from a small drug molecule, a model peptide, a small protein, and an oligonucleotide were subjected to the DDC CID method in either an ion trapping or an ion transmission mode (or both). Several key experimental parameters that affect DDC CID results, such as time, voltage, low mass cutoff, and bath gas pressure, are illustrated with protonated leucine enkephalin. The DDC CID dissociation method gives a readily tunable, broadband tool for probing the primary structures of a wide range of analyte ions. The method provides an alternative to the narrow resonance conditions of conventional ion trap CID and it can access more extensive sequential fragmentation, depending upon conditions. The DDC CID approach constitutes a collision analog to infrared multiphoton dissociation (IRMPD). Copyright © 2011 John Wiley & Sons, Ltd.

  12. Identification of monohydroxy progesterones produced by CYP106A2 using comparative HPLC and electrospray ionisation collision-induced dissociation mass spectrometry

    International Nuclear Information System (INIS)

    Lisurek, Michael; Kang, M.-J.; Hartmann, Rolf W.; Bernhardt, Rita

    2004-01-01

    Two previously uncharacterised products, produced by recombinant CYP106A2 of Bacillus megaterium ATCC 13368 using progesterone as substrate, were identified. For this purpose a combination of comparative HPLC and electrospray ionisation collision induced dissociation mass spectrometry (ESI CID MS) was established and applied for rapid identification of the steroids, which were identified as 11α-hydroxyprogesterone and 9α-hydroxyprogesterone. The pharmaceutical relevance of these steroids is discussed. Furthermore, the hydroxylation activity was quantified for all monohydroxylation products (15β-hydroxyprogesterone, 6β-hydroxyprogesterone, 11α-hydroxyprogesterone, and 9α-hydroxyprogesterone). The V max values for 15β-hydroxyprogesterone, 6β-hydroxyprogesterone, 11α-hydroxyprogesterone, and 9α-hydroxyprogesterone were determined as 337.3 ± 43.7, 22.3 ± 0.9, 17.5 ± 0.9, and 6.5 ± 0.3 nmol product/min/nmol CYP106A2, respectively

  13. Quantitative correlations between collision induced dissociation mass spectrometry coupled with electrospray ionization or atmospheric pressure chemical ionization mass spectrometry - Experiment and theory

    Science.gov (United States)

    Ivanova, Bojidarka; Spiteller, Michael

    2018-04-01

    The problematic that we consider in this paper treats the quantitative correlation model equations between experimental kinetic and thermodynamic parameters of coupled electrospray ionization (ESI) mass spectrometry (MS) or atmospheric pressure chemical ionization (APCI) mass spectrometry with collision induced dissociation mass spectrometry, accounting for the fact that the physical phenomena and mechanisms of ESI- and APCI-ion formation are completely different. There are described forty two fragment reactions of three analytes under independent ESI- and APCI-measurements. The developed new quantitative models allow us to study correlatively the reaction kinetics and thermodynamics using the methods of mass spectrometry, which complementary application with the methods of the quantum chemistry provide 3D structural information of the analytes. Both static and dynamic quantum chemical computations are carried out. The object of analyses are [2,3-dimethyl-4-(4-methyl-benzoyl)-2,3-di-p-tolyl-cyclobutyl]-p-tolyl-methanone (1) and the polycyclic aromatic hydrocarbons derivatives of dibenzoperylen (2) and tetrabenzo [a,c,fg,op]naphthacene (3), respectively. As far as (1) is known to be a product of [2π+2π] cycloaddition reactions of chalcone (1,3-di-p-tolyl-propenone), however producing cyclic derivatives with different stereo selectivity, so that the study provide crucial data about the capability of mass spectrometry to provide determine the stereo selectivity of the analytes. This work also first provides quantitative treatment of the relations '3D molecular/electronic structures'-'quantum chemical diffusion coefficient'-'mass spectrometric diffusion coefficient', thus extending the capability of the mass spectrometry for determination of the exact 3D structure of the analytes using independent measurements and computations of the diffusion coefficients. The determination of the experimental diffusion parameters is carried out within the 'current monitoring method

  14. Differentiating chondroitin sulfate glycosaminoglycans using collision-induced dissociation; uronic acid cross-ring diagnostic fragments in a single stage of tandem mass spectrometry.

    Science.gov (United States)

    Kailemia, Muchena J; Patel, Anish B; Johnson, Dane T; Li, Lingyun; Linhardt, Robert J; Amster, I Jonathan

    2015-01-01

    The stereochemistry of the hexuronic acid residues of the structure of glycosaminoglycans (GAGs) is a key feature that affects their interactions with proteins and other biological functions. Electron based tandem mass spectrometry methods, in particular electron detachment dissociation (EDD), have been able to distinguish glucuronic acid (GlcA) from iduronic acid (IdoA) residues in some heparan sulfate tetrasaccharides by producing epimer-specific fragments. Similarly, the relative abundance of glycosidic fragment ions produced by collision-induced dissociation (CID) or EDD has been shown to correlate with the type of hexuronic acid present in chondroitin sulfate GAGs. The present work examines the effect of charge state and degree of sodium cationization on the CID fragmentation products that can be used to distinguish GlcA and IdoA containing chondroitin sulfate A and dermatan sulfate chains. The cross-ring fragments (2,4)A(n) and (0,2)X(n) formed within the hexuronic acid residues are highly preferential for chains containing GlcA, distinguishing it from IdoA. The diagnostic capability of the fragments requires the selection of a molecular ion and fragment ions with specific ionization characteristics, namely charge state and number of ionizable protons. The ions with the appropriate characteristics display diagnostic properties for all the chondroitin sulfate and dermatan sulfate chains (degree of polymerization of 4-10) studied.

  15. Statistical modeling of competitive threshold collision-induced dissociation

    Science.gov (United States)

    Rodgers, M. T.; Armentrout, P. B.

    1998-08-01

    Collision-induced dissociation of (R1OH)Li+(R2OH) with xenon is studied using guided ion beam mass spectrometry. R1OH and R2OH include the following molecules: water, methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol. In all cases, the primary products formed correspond to endothermic loss of one of the neutral alcohols, with minor products that include those formed by ligand exchange and loss of both ligands. The cross-section thresholds are interpreted to yield 0 and 298 K bond energies for (R1OH)Li+-R2OH and relative Li+ binding affinities of the R1OH and R2OH ligands after accounting for the effects of multiple ion-molecule collisions, internal energy of the reactant ions, and dissociation lifetimes. We introduce a means to simultaneously analyze the cross sections for these competitive dissociations using statistical theories to predict the energy dependent branching ratio. Thermochemistry in good agreement with previous work is obtained in all cases. In essence, this statistical approach provides a detailed means of correcting for the "competitive shift" inherent in multichannel processes.

  16. Direct glycan structure determination of intact N-linked glycopeptides by low-energy collision-induced dissociation tandem mass spectrometry and predicted spectral library searching.

    Science.gov (United States)

    Pai, Pei-Jing; Hu, Yingwei; Lam, Henry

    2016-08-31

    Intact glycopeptide MS analysis to reveal site-specific protein glycosylation is an important frontier of proteomics. However, computational tools for analyzing MS/MS spectra of intact glycopeptides are still limited and not well-integrated into existing workflows. In this work, a new computational tool which combines the spectral library building/searching tool, SpectraST (Lam et al. Nat. Methods2008, 5, 873-875), and the glycopeptide fragmentation prediction tool, MassAnalyzer (Zhang et al. Anal. Chem.2010, 82, 10194-10202) for intact glycopeptide analysis has been developed. Specifically, this tool enables the determination of the glycan structure directly from low-energy collision-induced dissociation (CID) spectra of intact glycopeptides. Given a list of possible glycopeptide sequences as input, a sample-specific spectral library of MassAnalyzer-predicted spectra is built using SpectraST. Glycan identification from CID spectra is achieved by spectral library searching against this library, in which both m/z and intensity information of the possible fragmentation ions are taken into consideration for improved accuracy. We validated our method using a standard glycoprotein, human transferrin, and evaluated its potential to be used in site-specific glycosylation profiling of glycoprotein datasets from LC-MS/MS. In addition, we further applied our method to reveal, for the first time, the site-specific N-glycosylation profile of recombinant human acetylcholinesterase expressed in HEK293 cells. For maximum usability, SpectraST is developed as part of the Trans-Proteomic Pipeline (TPP), a freely available and open-source software suite for MS data analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Axial spatial distribution focusing: improving MALDI-TOF/RTOF mass spectrometric performance for high-energy collision-induced dissociation of biomolecules.

    Science.gov (United States)

    Belgacem, O; Pittenauer, E; Openshaw, M E; Hart, P J; Bowdler, A; Allmaier, G

    2016-02-15

    For the last two decades, curved field reflectron technology has been used in matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometers, assisting in the generation of post-source-decay (PSD) or collision-induced dissociation (CID) without decelerating precursor ions, producing true high-energy CID spectra. The result was the generation of product ion mass spectra with product ions typical of high-energy (10 keV and beyond) collision processes. The disadvantage of this approach was the lack of resolution in CID spectra resulting from the excess laser energy deposition used to generate those MS/MS spectra. The work presented in this study overcomes this limitation and includes comprehensive examples of high-energy and high-resolution CID MALDI-MS/MS spectra of biomolecules. The devices used in this study are TOF/RTOF instruments equipped with a high-vacuum MALDI ion source. High-resolution and high-energy CID spectra result from the use of axial spatial distribution focusing (ASDF) in combination with curved field reflectron technology. A CID spectrum of the P14 R1 peptide exhibits product ion resolution in excess of 10,000 (FWHM) but at the same time yields typical high-energy product ions such as w- and [y-2]-type ion series. High-energy CID spectra of lipids, exemplified by a glycerophospholipid and triglyceride, demonstrate C-C backbone fragmentation elucidating the presence of a hydroxyl group in addition to double-bond positioning. A complex high mannose carbohydrate (Man)8 (GlcNAc)2 was also studied at 20 keV collision energy and revealed further high-energy product ions with very high resolution, allowing unambiguous detection and characterization of cross-ring cleavage-related ions. This is the first comprehensive study using a MALDI-TOF/RTOF instrument equipped with a curved field reflectron and an ASDF device prior to the reflectron. © 2015 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley

  18. Semiclassical calculation for collision induced dissociation. II. Morse oscillator model

    International Nuclear Information System (INIS)

    Rusinek, I.; Roberts, R.E.

    1978-01-01

    A recently developed semiclassical procedure for calculating collision induced dissociation probabilities P/sup diss/ is applied to the collinear collision between a particle and a Morse oscillator diatomic. The particle--diatom interaction is described with a repulsive exponential potential function. P/sup diss/ is reported for a system of three identical particles, as a function of collision energy E/sub t/ and initial vibrational state of the diatomic n 1 . The results are compared with the previously reported values for the collision between a particle and a truncated harmonic oscillator. The two studies show similar features, namely: (a) there is an oscillatory structure in the P/sup diss/ energy profiles, which is directly related to n 1 ; (b) P/sup diss/ becomes noticeable (> or approx. =10 -3 ) for E/sub t/ values appreciably higher than the energetic threshold; (c) vibrational enhancement (inhibition) of collision induced dissociation persists at low (high) energies; and (d) good agreement between the classical and semiclassical results is found above the classical dynamic threshold. Finally, the convergence of P/sup diss/ for increasing box length is shown to be rapid and satisfactory

  19. MALDI-TOF MS coupled with collision-induced dissociation (CID) measurements of poly(methyl methacrylate)

    NARCIS (Netherlands)

    Baumgaertel, A.; Becer, C.R.; Gottschaldt, M.; Schubert, U.S.

    2008-01-01

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was chosen for an in-detail analysis of poly(methyl methacrylate) (PMMA) in order to determine the possible fragmentation mechanism with the help of collision-induced dissociation (CID). All experiments were

  20. Electron Transfer and Collision Induced Dissociation of Non-Derivatized and Derivatized Desmosine and Isodesmosine

    NARCIS (Netherlands)

    Ongay, Sara; Hermans, Jos; Bruins, Andries P.; Nieuwendijk, Adrianus M. C. H.; Overkleeft, Hermen; Bischoff, Rainer

    Electron transfer dissociation (ETD) has attracted increasing interest due to its complementarity to collision-induced dissociation (CID). ETD allows the direct localization of labile post-translational modifications, which is of main interest in proteomics where differences and similarities between

  1. Towards understanding the tandem mass spectra of protonated oligopeptides. 2: The proline effect in collision-induced dissociation of protonated Ala-Ala-Xxx-Pro-Ala (Xxx = Ala, Ser, Leu, Val, Phe, and Trp).

    Science.gov (United States)

    Bleiholder, Christian; Suhai, Sándor; Harrison, Alex G; Paizs, Béla

    2011-06-01

    The product ion spectra of proline-containing peptides are commonly dominated by y(n) ions generated by cleavage at the N-terminal side of proline residues. This proline effect is investigated in the current work by collision-induced dissociation (CID) of protonated Ala-Ala-Xxx-Pro-Ala (Xxx includes Ala, Ser, Leu, Val, Phe, and Trp) in an electrospray/quadrupole/time-of-flight (QqTOF) mass spectrometer and by quantum chemical calculations on protonated Ala-Ala-Ala-Pro-Ala. The CID spectra of all investigated peptides show a dominant y(2) ion (Pro-Ala sequence). Our computational results show that the proline effect mainly arises from the particularly low threshold energy for the amide bond cleavage N-terminal to the proline residue, and from the high proton affinity of the proline-containing C-terminal fragment produced by this cleavage. These theoretical results are qualitatively supported by the experimentally observed y(2)/b(3) abundance ratios for protonated Ala-Ala-Xxx-Pro-Ala (Xxx = Ala, Ser, Leu, Val, Phe, and Trp). In the post-cleavage phase of fragmentation the N-terminal oxazolone fragment with the Ala-Ala-Xxx sequence and Pro-Ala compete for the ionizing proton for these peptides. As the proton affinity of the oxazolone fragment increases, the y(2)/b(3) abundance ratio decreases.

  2. Collision-Induced Dissociation Study of Strong Hydrogen-Bonded Cluster Ions Y-(HF) n (Y=F, O2) Using Atmospheric Pressure Corona Discharge Ionization Mass Spectrometry Combined with a HF Generator.

    Science.gov (United States)

    Sakamoto, Kenya; Sekimoto, Kanako; Takayama, Mitsuo

    2017-01-01

    Hydrogen fluoride (HF) was produced by a homemade HF generator in order to investigate the properties of strong hydrogen-bonded clusters such as (HF) n . The HF molecules were ionized in the form of complex ions associated with the negative core ions Y - produced by atmospheric pressure corona discharge ionization (APCDI). The use of APCDI in combination with the homemade HF generator led to the formation of negative-ion HF clusters Y - (HF) n (Y=F, O 2 ), where larger clusters with n ≥4 were not detected. The mechanisms for the formation of the HF, F - (HF) n , and O 2 - (HF) n species were discussed from the standpoints of the HF generator and APCDI MS. By performing energy-resolved collision-induced dissociation (CID) experiments on the cluster ions F - (HF) n ( n =1-3), the energies for the loss of HF from F - (HF) 3 , F - (HF) 2 , and F - (HF) were evaluated to be 1 eV or lower, 1 eV or higher, and 2 eV, respectively, on the basis of their center-of-mass energy ( E CM ). These E CM values were consistent with the values of 0.995, 1.308, and 2.048 eV, respectively, obtained by ab initio calculations. The stability of [O 2 (HF) n ] - ( n =1-4) was discussed on the basis of the bond lengths of O 2 H-F - (HF) n and O 2 - H-F(HF) n obtained by ab initio calculations. The calculations indicated that [O 2 (HF) 4 ] - separated into O 2 H and F - (HF) 3 .

  3. In-tube collision-induced dissociation for selected ion flow-drift tube mass spectrometry, SIFDT-MS: a case study of NO+ reactions with isomeric monoterpenes

    Czech Academy of Sciences Publication Activity Database

    Spesyvyi, Anatolii; Sovová, Kristýna; Španěl, Patrik

    2016-01-01

    Roč. 30, č. 18 (2016), s. 2009-2016 ISSN 0951-4198 R&D Projects: GA ČR GA13-28882S Institutional support: RVO:61388955 Keywords : mass spectroscopy * SIFDT-MS * isomeric monoterpenes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.998, year: 2016

  4. Profiling monoterpenol glycoconjugation in Vitis vinifera L. cv. Muscat of Alexandria using a novel putative compound database approach, high resolution mass spectrometry and collision induced dissociation fragmentation analysis.

    Science.gov (United States)

    Hjelmeland, Anna K; Zweigenbaum, Jerry; Ebeler, Susan E

    2015-08-05

    In this work we present a novel approach for the identification of plant metabolites using ultrahigh performance liquid chromatography coupled to accurate mass time-of-flight mass spectrometry. The workflow involves developing an in-house compound database consisting of exact masses of previously identified as well as putative compounds. The database is used to screen accurate mass spectrometry (MS) data to identify possible compound matches. Subsequent tandem MS data is acquired for possible matches and used for structural elucidation. The methodology is applied to profile monoterpene glycosides in Vitis vinifera cv. Muscat of Alexandria grape berries over three developmental stages. Monoterpenes are a subclass of terpenes, the largest class of plant secondary metabolites, and are found in two major forms in the plant, "bound" to one or more sugar moieties or "free" of said sugar moieties. In the free form, monoterpenes are noted for their fragrance and play important roles in plant defense and as attractants for pollinators. However, glycoconjugation renders these compounds odorless, and it is this form that the plant uses for monoterpene storage. In order to gain insight into monoterpene biochemistry and their fate in the plant an analysis of intact glycosides is essential. Eighteen monoterpene glycosides were identified including a monoterpene trisaccharide glycoside, which is tentatively identified here for this first time in any plant. Additionally, while previous studies have identified monoterpene malonylated glucosides in other grapevine tissue, we tentatively identify them for the first time in grape berries. This analytical approach can be readily applied to other plants and the workflow approach can also be used for other classes of compounds. This approach, in general, provides researchers with data to support the identification of putative compounds, which is especially useful when no standard is available. Copyright © 2015 Elsevier B.V. All rights

  5. Simple quantal model for collision-induced dissociation: An Airy basis calculation

    International Nuclear Information System (INIS)

    Hunt, P.M.; Sridharan, S.

    1982-01-01

    New matrix elements for the Airy continuum basis are employed to find quantum mechanical dissociation probabilities for the the forced Morse oscillator. The calculations performed illustrate the ease with which the continuously infinite Airy basis can be manipulated, and they illustrate the transition from vibrational enhancement to vibrational inhibition of diatomic breakup. The forced Morse oscillator model thus reproduces the behavior of more complicated collinear collision-induced dissociation systems

  6. Electron Transfer Dissociation and Collision-Induced Dissociation of Underivatized Metallated Oligosaccharides

    Science.gov (United States)

    Schaller-Duke, Ranelle M.; Bogala, Mallikharjuna R.; Cassady, Carolyn J.

    2018-05-01

    Electron transfer dissociation (ETD) and collision-induced dissociation (CID) were used to investigate underivatized, metal-cationized oligosaccharides formed via electrospray ionization (ESI). Reducing and non-reducing sugars were studied including the tetrasaccharides maltotetraose, 3α,4β,3α-galactotetraose, stachyose, nystose, and a heptasaccharide, maltoheptaose. Univalent alkali, divalent alkaline earth, divalent and trivalent transition metal ions, and a boron group trivalent metal ion were adducted to the non-permethylated oligosaccharides. ESI generated [M + Met]+, [M + 2Met]2+, [M + Met]2+, [M + Met - H]+, and [M + Met - 2H]+ most intensely along with low intensity nitrate adducts, depending on the metal and sugar ionized. The ability of these metal ions to produce oligosaccharide adduct ions by ESI had the general trend: Ca(II) > Mg(II) > Ni(II) > Co(II) > Zn(II) > Cu(II) > Na(I) > K(I) > Al(III) ≈ Fe(III) ≈ Cr(III). Although trivalent metals were utilized, no triply charged ions were formed. Metal cations allowed for high ESI signal intensity without permethylation. ETD and CID on [M + Met]2+ produced various glycosidic and cross-ring cleavages, with ETD producing more cross-ring and internal ions, which are useful for structural analysis. Product ion intensities varied based on glycosidic-bond linkage and identity of monosaccharide sub-unit, and metal adducts. ETD and CID showed high fragmentation efficiency, often with complete precursor dissociation, depending on the identity of the adducted metal ion. Loss of water was occasionally observed, but elimination of small neutral molecules was not prevalent. For both ETD and CID, [M + Co]2+ produced the most uniform structurally informative dissociation with all oligosaccharides studied. The ETD and CID spectra were complementary. [Figure not available: see fulltext.

  7. Electron Transfer Dissociation and Collision-Induced Dissociation of Underivatized Metallated Oligosaccharides

    Science.gov (United States)

    Schaller-Duke, Ranelle M.; Bogala, Mallikharjuna R.; Cassady, Carolyn J.

    2018-02-01

    Electron transfer dissociation (ETD) and collision-induced dissociation (CID) were used to investigate underivatized, metal-cationized oligosaccharides formed via electrospray ionization (ESI). Reducing and non-reducing sugars were studied including the tetrasaccharides maltotetraose, 3α,4β,3α-galactotetraose, stachyose, nystose, and a heptasaccharide, maltoheptaose. Univalent alkali, divalent alkaline earth, divalent and trivalent transition metal ions, and a boron group trivalent metal ion were adducted to the non-permethylated oligosaccharides. ESI generated [M + Met]+, [M + 2Met]2+, [M + Met]2+, [M + Met - H]+, and [M + Met - 2H]+ most intensely along with low intensity nitrate adducts, depending on the metal and sugar ionized. The ability of these metal ions to produce oligosaccharide adduct ions by ESI had the general trend: Ca(II) > Mg(II) > Ni(II) > Co(II) > Zn(II) > Cu(II) > Na(I) > K(I) > Al(III) ≈ Fe(III) ≈ Cr(III). Although trivalent metals were utilized, no triply charged ions were formed. Metal cations allowed for high ESI signal intensity without permethylation. ETD and CID on [M + Met]2+ produced various glycosidic and cross-ring cleavages, with ETD producing more cross-ring and internal ions, which are useful for structural analysis. Product ion intensities varied based on glycosidic-bond linkage and identity of monosaccharide sub-unit, and metal adducts. ETD and CID showed high fragmentation efficiency, often with complete precursor dissociation, depending on the identity of the adducted metal ion. Loss of water was occasionally observed, but elimination of small neutral molecules was not prevalent. For both ETD and CID, [M + Co]2+ produced the most uniform structurally informative dissociation with all oligosaccharides studied. The ETD and CID spectra were complementary. [Figure not available: see fulltext.

  8. Fully-converged three-dimensional collision-induced dissociation calculations with Faddeev-AGS theory

    International Nuclear Information System (INIS)

    Haftel, M.I.; Lim, T.K.

    1981-09-01

    The first fully-converged quantum-mechanical calculation of the collision-induced dissociation cross section in a three-dimensional-model system of three helium-like atoms is reported. Faddeev-AGS theory is used. It yields as a bonus the elastic atom-diatom cross section. The obtained results resemble those from some collinear models but indicate clearly the futility of multiple-scattering approximations except at hyperthermal energies. (orig.)

  9. Three-Body Collision Contributions to Recombination and Collision-Induced Dissociation. II. Kinetics

    International Nuclear Information System (INIS)

    Kendrick, Brian; Pack, Russell T.; Walker, Robert B.

    1998-01-01

    Detailed rate constants for the reaction Ne + Ne + H r e quilibrium Ne 2 + H are generated, and the master equations governing collision-induced dissociation (CID) and recombination are accurately solved numerically. The temperature and pressure dependence are explored. At all pressures, three-body (3B) collisions dominate. The sequential two-body energy-transfer (ET) mechanism gives a rate that is more than a factor of two too small at low pressures and orders of magnitude too small at high pressures. Simpler models are explored; to describe the kinetics they must include direct 3B rates connecting the continuum to the bound states and to the quasibound states. The relevance of the present reaction to more general CID/recombination reactions is discussed. For atomic fragments, the 3B mechanism usually dominates. For diatomic fragments,the 3B and ET mechanism are competitive, and for polyatomic fragments the ET mechanism usually dominates

  10. Threshold collision-induced dissociation of diatomic molecules: a case study of the energetics and dynamics of O2- collisions with Ar and Xe.

    Science.gov (United States)

    Ahu Akin, F; Ree, Jongbaik; Ervin, Kent M; Kyu Shin, Hyung

    2005-08-08

    The energetics and dynamics of collision-induced dissociation of O2- with Ar and Xe targets are studied experimentally using guided ion-beam tandem mass spectrometry. The cross sections and the collision dynamics are modeled theoretically by classical trajectory calculations. Experimental apparent threshold energies are 2.1 and 1.1 eV in excess of the thermochemical O2- bond dissociation energy for argon and xenon, respectively. Classical trajectory calculations confirm the observed threshold behavior and the dependence of cross sections on the relative kinetic energy. Representative trajectories reveal that the bond dissociation takes place on a short time scale of about 50 fs in strong direct collisions. Collision-induced dissociation is found to be remarkably restricted to the perpendicular approach of ArXe to the molecular axis of O2-, while collinear collisions do not result in dissociation. The higher collisional energy-transfer efficiency of xenon compared with argon is attributed to both mass and polarizability effects.

  11. Threshold collision-induced dissociation of diatomic molecules: A case study of the energetics and dynamics of O2- collisions with Ar and Xe

    International Nuclear Information System (INIS)

    Ahu Akin, F.; Ree, Jongbaik; Ervin, Kent M.; Hyung, Kyu Shin

    2005-01-01

    The energetics and dynamics of collision-induced dissociation of O 2 - with Ar and Xe targets are studied experimentally using guided ion-beam tandem mass spectrometry. The cross sections and the collision dynamics are modeled theoretically by classical trajectory calculations. Experimental apparent threshold energies are 2.1 and 1.1 eV in excess of the thermochemical O 2 - bond dissociation energy for argon and xenon, respectively. Classical trajectory calculations confirm the observed threshold behavior and the dependence of cross sections on the relative kinetic energy. Representative trajectories reveal that the bond dissociation takes place on a short time scale of about 50 fs in strong direct collisions. Collision-induced dissociation is found to be remarkably restricted to the perpendicular approach of Ar/Xe to the molecular axis of O 2 - , while collinear collisions do not result in dissociation. The higher collisional energy-transfer efficiency of xenon compared with argon is attributed to both mass and polarizability effects

  12. How Hot are Your Ions Really? A Threshold Collision-Induced Dissociation Study of Substituted Benzylpyridinium "Thermometer" Ions

    Science.gov (United States)

    Carpenter, John E.; McNary, Christopher P.; Furin, April; Sweeney, Andrew F.; Armentrout, P. B.

    2017-09-01

    The first absolute experimental bond dissociation energies (BDEs) for the main heterolytic bond cleavages of four benzylpyridinium "thermometer" ions are measured using threshold collision-induced dissociation in a guided ion beam tandem mass spectrometer. In this experiment, substituted benzylpyridinium ions are introduced into the apparatus using an electrospray ionization source, thermalized, and collided with Xe at varied kinetic energies to determine absolute cross-sections for these reactions. Various effects are accounted for, including kinetic shifts, multiple collisions, and internal and kinetic energy distributions. These experimentally measured 0 K BDEs are compared with computationally predicted values at the B3LYP-GD3BJ, M06-GD3, and MP2(full) levels of theory with a 6-311+G(2d,2p) basis set using vibrational frequencies and geometries determined at the B3LYP/6-311+G(d,p) level. Additional dissociation pathways are observed for nitrobenzylpyridinium experimentally and investigated using these same levels of theory. Experimental BDEs are also compared against values in the literature at the AM1, HF, B3LYP, B3P86, and CCSD(T) levels of theory. Of the calculated values obtained in this work, the MP2(full) level of theory with counterpoise corrections best reproduces the experimental results, as do the similar literature CCSD(T) values. Lastly, the survival yield method is used to determine the characteristic temperature (Tchar) of the electrospray source prior to the thermalization region and to confirm efficient thermalization. [Figure not available: see fulltext.

  13. Influence of Background H2O on the Collision-Induced Dissociation Products Generated from [UO2NO3]+

    Science.gov (United States)

    Van Stipdonk, Michael J.; Iacovino, Anna; Tatosian, Irena

    2018-04-01

    Developing a comprehensive understanding of the reactivity of uranium-containing species remains an important goal in areas ranging from the development of nuclear fuel processing methods to studies of the migration and fate of the element in the environment. Electrospray ionization (ESI) is an effective way to generate gas-phase complexes containing uranium for subsequent studies of intrinsic structure and reactivity. Recent experiments by our group have demonstrated that the relatively low levels of residual H2O in a 2-D, linear ion trap (LIT) make it possible to examine fragmentation pathways and reactions not observed in earlier studies conducted with 3-D ion traps (Van Stipdonk et al. J. Am. Soc. Mass Spectrom. 14, 1205-1214, 2003). In the present study, we revisited the dissociation of complexes composed of uranyl nitrate cation [UVIO2(NO3)]+ coordinated by alcohol ligands (methanol and ethanol) using the 2-D LIT. With relatively low levels of background H2O, collision-induced dissociation (CID) of [UVIO2(NO3)]+ primarily creates [UO2(O2)]+ by the ejection of NO. However, CID (using He as collision gas) of [UVIO2(NO3)]+ creates [UO2(H2O)]+ and UO2 + when the 2-D LIT is used with higher levels of background H2O. Based on the results presented here, we propose that product ion spectrum in the previous experiments was the result of a two-step process: initial formation of [UVIO2(O2)]+ followed by rapid exchange of O2 for H2O by ion-molecule reaction. Our experiments illustrate the impact of residual H2O in ion trap instruments on the product ions generated by CID and provide a more accurate description of the intrinsic dissociation pathway for [UVIO2(NO3)]+. [Figure not available: see fulltext.

  14. Collision-induced dissociation of noncovalent complexes between vancomycin antibiotics and peptide ligand stereoisomers: evidence for molecular recognition in the gas phase

    DEFF Research Database (Denmark)

    Jørgensen, Thomas J. D.; Delforge, D; Remacle, J

    1999-01-01

    In solution, the antibiotics of the vancomycin group bind stereospecifically to peptides with the C-terminal sequence: -L-Lys-D-Ala-D-Ala, Substitution by a L-Ala at either of the two C-terminal residues causes a dramatic decrease in the binding affinity to the antibiotics. This solution behavior...... is clearly reflected in electrospray ionization (ESI) mass spectra obtained from equimolar mixtures of an antibiotic, an isotopically labelled peptide ligand and an unlabelled peptide stereoisomer. Using collision-induced dissociation (CID) we have probed the gas phase stability of isomeric (1:1) noncovalent...

  15. Collision-Induced Dissociation of Electrosprayed Protein Complexes: An All-Atom Molecular Dynamics Model with Mobile Protons.

    Science.gov (United States)

    Popa, Vlad; Trecroce, Danielle A; McAllister, Robert G; Konermann, Lars

    2016-06-16

    Electrospray ionization mass spectrometry (ESI-MS) has become an indispensable technique for examining noncovalent protein complexes. Collision-induced dissociation (CID) of these multiply protonated gaseous ions usually culminates in ejection of a single subunit with a disproportionately large amount of charge. Experiments suggest that this process involves subunit unfolding prior to separation from the residual complex, as well as H(+) migration onto the unravelling chain. Molecular dynamics (MD) simulations are a promising avenue for gaining detailed insights into these CID events. Unfortunately, typical MD algorithms do not allow for mobile protons. Here we address this limitation by implementing a strategy that combines atomistic force fields (such as OPLS/AA and CHARMM36) with a proton hopping algorithm, focusing on the tetrameric complexes transthyretin and streptavidin. Protons are redistributed over all acidic and basic sites in 20 ps intervals, subject to an energy function that reflects electrostatic interactions and proton affinities. Our simulations predict that nativelike conformers at the onset of collisional heating contain multiple salt bridges. Collisional heating initially causes subtle structural changes that lead to a gradual decline of these zwitterionic patterns. Many of the MD runs show gradual unfolding of a single subunit in conjunction with H(+) migration, culminating in subunit separation from the complex. However, there are also instances where two or more chains start to unfold simultaneously, giving rise to charge competition. The scission point where the "winning" subunit separates from the complex can be attained for different degrees of unfolding, giving rise to product ions in various charge states. The simulated product ion distributions are in close agreement with experimental CID data. Proton enrichment in the departing subunit is driven by charge-charge repulsion, but the combination of salt bridge depletion, charge migration

  16. Semiclassical calculation for collision induced dissociation. III. Restricted two dimensional Morse oscillator model

    International Nuclear Information System (INIS)

    Rusinek, I.

    1980-01-01

    A semiclassical procedure previously used for collinear CID calculations is applied to the perpendicular collisions (2D, no rotation, zero impact parameter) of a Morse homonuclear diatomic molecule and an atom, interacting via an exponential repulsive potential. Values of the dissociation probability (P/sup diss/) are given as a function of total energy (E/sub t/) and initial vibrational state (n 1 =0,1,3,5) for a system with three identical masses. The results are compared with the P/sup diss/ previously reported for an identical one dimensional system. We find: (a) quasiclassical P/sup diss/ that are a good approximation to the semiclassical ones, if CID is classically allowed, (b) vibrational enhancement of CID, and (c) energetic thresholds for dissociation similar to the ones found in the collinear case

  17. Strategy to improve the quantitative LC-MS analysis of molecular ions resistant to gas-phase collision induced dissociation: application to disulfide-rich cyclic peptides.

    Science.gov (United States)

    Ciccimaro, Eugene; Ranasinghe, Asoka; D'Arienzo, Celia; Xu, Carrie; Onorato, Joelle; Drexler, Dieter M; Josephs, Jonathan L; Poss, Michael; Olah, Timothy

    2014-12-02

    Due to observed collision induced dissociation (CID) fragmentation inefficiency, developing sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) assays for CID resistant compounds is especially challenging. As an alternative to traditional LC-MS/MS, we present here a methodology that preserves the intact analyte ion for quantification by selectively filtering ions while reducing chemical noise. Utilizing a quadrupole-Orbitrap MS, the target ion is selectively isolated while interfering matrix components undergo MS/MS fragmentation by CID, allowing noise-free detection of the analyte's surviving molecular ion. In this manner, CID affords additional selectivity during high resolution accurate mass analysis by elimination of isobaric interferences, a fundamentally different concept than the traditional approach of monitoring a target analyte's unique fragment following CID. This survivor-selected ion monitoring (survivor-SIM) approach has allowed sensitive and specific detection of disulfide-rich cyclic peptides extracted from plasma.

  18. Separation and identification of structural isomers by quadrupole collision-induced dissociation-hydrogen/deuterium exchange-infrared multiphoton dissociation (QCID-HDX-IRMPD).

    Science.gov (United States)

    Gucinski, Ashley C; Somogyi, Arpád; Chamot-Rooke, Julia; Wysocki, Vicki H

    2010-08-01

    A new approach that uses a hybrid Q-FTICR instrument and combines quadrupole collision-induced dissociation, hydrogen-deuterium exchange, and infrared multiphoton dissociation (QCID-HDX-IRMPD) has been shown to effectively separate and differentiate isomeric fragment ion structures present at the same m/z. This method was used to study protonated YAGFL-OH (free acid), YAGFL-NH(2) (amide), cyclic YAGFL, and YAGFL-OCH(3) (methyl ester). QCID-HDX of m/z 552.28 (C(29)H(38)N(5)O(6)) from YAGFL-OH reveals at least two distributions of ions corresponding to the b(5) ion and a non-C-terminal water loss ion structure. Subsequent IRMPD fragmentation of each population shows distinct fragmentation patterns, reflecting the different structures from which they arise. This contrasts with data for YAGFL-NH(2) and YAGFL-OCH(3), which do not show two distinct H/D exchange populations for the C(29)H(38)N(5)O(6) structure formed by NH(3) and HOCH(3) loss, respectively. Relative extents of exchange for C(29)H(38)N(5)O(6) ions from six sequence isomers (YAGFL, AGFLY, GFLYA, FLYAG, LYAGF, and LFGAY) show a sequence dependence of relative isomer abundance. Supporting action IRMPD spectroscopy data are also presented herein and also show that multiple structures are present for the C(29)H(38)N(5)O(6) species from YAGFL-OH. Copyright 2010. Published by Elsevier Inc.

  19. Simultaneous Quantification of Free Cholesterol, Cholesteryl Esters, and Triglycerides without Ester Hydrolysis by UHPLC Separation and In-Source Collision Induced Dissociation Coupled MS/MS

    Science.gov (United States)

    Gardner, Michael S.; McWilliams, Lisa G.; Jones, Jeffrey I.; Kuklenyik, Zsuzsanna; Pirkle, James L.; Barr, John R.

    2017-08-01

    We demonstrate the application of in-source nitrogen collision-induced dissociation (CID) that eliminates the need for ester hydrolysis before simultaneous analysis of esterified cholesterol (EC) and triglycerides (TG) along with free cholesterol (FC) from human serum, using normal phase liquid chromatography (LC) coupled to atmospheric pressure chemical ionization (APCI) tandem mass spectrometry (MS/MS). The analysis requires only 50 μL of 1:100 dilute serum with a high-throughput, precipitation/evaporation/extraction protocol in one pot. Known representative mixtures of EC and TG species were used as calibrators with stable isotope labeled analogs as internal standards. The APCI MS source was operated with nitrogen source gas. Reproducible in-source CID was achieved with the use of optimal cone voltage (declustering potential), generating FC, EC, and TG lipid class-specific precursor fragment ions for multiple reaction monitoring (MRM). Using a representative mixture of purified FC, CE, and TG species as calibrators, the method accuracy was assessed with analysis of five inter-laboratory standardization materials, showing -10% bias for Total-C and -3% for Total-TG. Repeated duplicate analysis of a quality control pool showed intra-day and inter-day variation of 5% and 5.8% for FC, 5.2% and 8.5% for Total-C, and 4.1% and 7.7% for Total-TG. The applicability of the method was demonstrated on 32 serum samples and corresponding lipoprotein sub-fractions collected from normolipidemic, hypercholesterolemic, hypertriglyceridemic, and hyperlipidemic donors. The results show that in-source CID coupled with isotope dilution UHPLC-MS/MS is a viable high precision approach for translational research studies where samples are substantially diluted or the amounts of archived samples are limited. [Figure not available: see fulltext.

  20. Native Mass Spectrometry, Ion mobility, and Collision-Induced Unfolding Categorize Malaria Antigen/Antibody Binding

    Science.gov (United States)

    Huang, Yining; Salinas, Nichole D.; Chen, Edwin; Tolia, Niraj H.; Gross, Michael L.

    2017-09-01

    Plasmodium vivax Duffy Binding Protein (PvDBP) is a promising vaccine candidate for P. vivax malaria. Recently, we reported the epitopes on PvDBP region II (PvDBP-II) for three inhibitory monoclonal antibodies (2D10, 2H2, and 2C6). In this communication, we describe the combination of native mass spectrometry and ion mobility (IM) with collision induced unfolding (CIU) to study the conformation and stabilities of three malarial antigen-antibody complexes. These complexes, when collisionally activated, undergo conformational changes that depend on the location of the epitope. CIU patterns for PvDBP-II in complex with antibody 2D10 and 2H2 are highly similar, indicating comparable binding topology and stability. A different CIU fingerprint is observed for PvDBP-II/2C6, indicating that 2C6 binds to PvDBP-II on an epitope different from 2D10 and 2H2. This work supports the use of CIU as a means of classifying antigen-antibody complexes by their epitope maps in a high throughput screening workflow. [Figure not available: see fulltext.

  1. Development and Optimization of an UPLC-QTOF-MS/MS Method Based on an In-Source Collision Induced Dissociation Approach for Comprehensive Discrimination of Chlorogenic Acids Isomers from Momordica Plant Species

    Directory of Open Access Journals (Sweden)

    N. E. Madala

    2014-01-01

    Full Text Available Chlorogenic acids (CGA have been profiled in the leaves of Momordica balsamina, Momordica charantia, and Momordica foetida. All three species were found to contain the trans and cis isomers of 4-acyl para-coumaroylquinic acid (pCoQA, caffeoylquinic acid (CQA, and feruloylquinic acid (FQA. To the best of our knowledge, this is the first report of pCoQA and FQA and their cis isomers in these Momordica species. These profiles were obtained by a newly developed UPLC-qTOF-MS method based on the in-source collision induced dissociation (ISCID method optimized to mimic the MS2 and MS3 fragmentation of an ion trap-based MS. The presence of the cis isomers is believed to be due to high UV exposure of these plants. Furthermore, the absence of the 3-acyl and 5-acyl CGA molecules points to a metabolic mark that is unusual and represents a very interesting biochemical phenotype of these species. Our optimized ISCID method was also shown to be able to distinguish between the geometrical isomers of all three forms of CGA, a phenomenon previously deemed impossible with other common mass spectrometry systems used for CGA analyses.

  2. Combined photoelectron, collision-induced dissociation, and computational studies of parent and fragment anions of N-paranitrophenylsulfonylalanine and N-paranitrophenylalanine

    Science.gov (United States)

    Lambert, Jason; Chen, Jing; Buonaugurio, Angela; Bowen, Kit H.; Do-Thanh, Chi-Linh; Wang, Yilin; Best, Michael D.; Compton, R. N.; Sommerfeld, Thomas

    2013-12-01

    After synthesizing the compounds N-paranitrophenylsulfonylalanine (NPNPSA) and N-paranitrophenylalanine (NPNPA), the photoelectron spectrum of the valence anion of N-paranitrophenylsulfonylalanine (NPNPSA)-, was measured and the collision-induced dissociation (CID) pathways of deprotonated N-paranitrophenylsulfonylalanine (NPNPSA-H)- and deprotonated N-paranitrophenylalanine (NPNPA-H)- were determined. Pertinent calculations were conducted to analyze both sets of experimental data. From the valence anion photoelectron spectrum of (NPNPSA)-, the adiabatic electron affinity (AEA) of NPNPSA was determined to be 1.7 ± 0.1 eV, while the vertical detachment energy (VDE) of (NPNPSA)- was found to be 2.3 ± 0.1 eV. Calculations for four low lying conformers of (NPNPSA)- gave AEA values in the range of 1.6-2.1 eV and VDE values in the range of 2.0-2.4 eV. These calculations are in very good agreement with the experimental values. While the NPNPA anion (NPNPSA)- was not observed experimentally it was studied computationally. The six low lying (NPNPSA)- conformers were identified and calculated to have AEA values in the range of 0.7-1.2 eV and VDE values in the range of 0.9-1.6 eV. CID was used to study the fragmentation patterns of deprotonated NPNPA and deprotonated NPNPSA. Based on the CID data and calculations, the excess charge was located on the delocalized π-orbitals of the nitrobenzene moiety. This is made evident by the fact that the dominant fragments all contained the nitrobenzene moiety even though the parent anions used for the CID study were formed via deprotonation of the carboxylic acid. The dipole-bound anions of both molecules are studied theoretically using the results of previous studies on nitrobenzene as a reference.

  3. Unique pentafluorobenzylation and collision-induced dissociation for specific and accurate GC-MS/MS quantification of the catecholamine metabolite 3,4-dihydroxyphenylglycol (DHPG) in human urine.

    Science.gov (United States)

    Zoerner, Alexander A; Heusser, Karsten; Gutzki, Frank M; Mitschke, Anja; Tank, Jens; Stichtenoth, Dirk O; Jordan, Jens; Tsikas, Dimitrios

    2011-05-15

    In the human body, the catecholamine norepinephrine is mainly metabolized to 3,4-dihydroxyphenylglycol (DHPG) which therefore serves as an important biomarker for norepinephrine's metabolism. Most data on DHPG concentrations in human plasma and urine has been generated by using HPLC-ECD or GC-MS technologies. Here, we describe a stable-isotope dilution GC-MS/MS method for the quantitative determination of DHPG in human urine using trideutero-DHPG (d(3)-DHPG) as internal standard and a two-step derivatization process with pentafluorobenzyl bromide (PFB-Br) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). Two pentafluorobenzyl (PFB) trimethylsilyl (TMS) derivatives were obtained and identified, i.e., two isomeric DHPG-PFB-(TMS)(3) derivatives and the later eluting DHPG-tetrafluorobenzyl-(TMS)(2) derivative, i.e., DHPG-TFB-(TMS)(2). To our knowledge the DHPG-TFB-(TMS)(2) derivative and the underlying reaction have not been reported previously. In this reaction both vicinal aromatic hydroxyl groups of DHPG react with PFB-Br to form a heterocyclic seven-membered [1,4]dioxepin compound. The DHPG-TFB-(TMS)(2) derivative was used for quantitative GC-MS/MS analysis in the electron-capturing negative-ion chemical ionization mode by selected-reaction monitoring of m/z 351 from m/z 401 for DHPG and of m/z 352 from m/z 404 for d(3)-DHPG. Validation experiments on human urine samples spiked with DHPG in a narrow (0-33 nM) and a wide range (0-901 nM) revealed high recovery (86-104%) and low imprecision (RSD; 0.01-2.8%). LOD and relative LLOQ (rLLOQ) values of the method for DHPG were determined to be 76 amol and 9.4%, respectively. In urine of 28 patients suffering from chronic inflammatory rheumatic diseases, DHPG was measured at a mean concentration of 238 nM (38.3 μg/g creatinine). The DHPG concentration in the respective control group of 40 healthy subjects was measured to be 328 nM (39.2 μg/g creatinine). Given the unique derivatization reaction and collision-induced

  4. Global proteomic profiling of phosphopeptides using electron transfer dissociation tandem mass spectrometry

    DEFF Research Database (Denmark)

    Molina, Henrik; Horn, David M; Tang, Ning

    2007-01-01

    Electron transfer dissociation (ETD) is a recently introduced mass spectrometric technique that provides a more comprehensive coverage of peptide sequences and posttranslational modifications. Here, we evaluated the use of ETD for a global phosphoproteome analysis. In all, we identified a total...... of 1,435 phosphorylation sites from human embryonic kidney 293T cells, of which 1,141 ( approximately 80%) were not previously described. A detailed comparison of ETD and collision-induced dissociation (CID) modes showed that ETD identified 60% more phosphopeptides than CID, with an average of 40% more...... fragment ions that facilitated localization of phosphorylation sites. Although our data indicate that ETD is superior to CID for phosphorylation analysis, the two methods can be effectively combined in alternating ETD and CID modes for a more comprehensive analysis. Combining ETD and CID, from this single...

  5. Characterization of Isomeric Glycans by Reversed Phase Liquid Chromatography-Electronic Excitation Dissociation Tandem Mass Spectrometry

    Science.gov (United States)

    Tang, Yang; Wei, Juan; Costello, Catherine E.; Lin, Cheng

    2018-04-01

    The occurrence of numerous structural isomers in glycans from biological sources presents a severe challenge for structural glycomics. The subtle differences among isomeric structures demand analytical methods that can provide structural details while working efficiently with on-line glycan separation methods. Although liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a powerful tool for mixture analysis, the commonly utilized collision-induced dissociation (CID) method often does not generate a sufficient number of fragments at the MS2 level for comprehensive structural characterization. Here, we studied the electronic excitation dissociation (EED) behaviors of metal-adducted, permethylated glycans, and identified key spectral features that could facilitate both topology and linkage determinations. We developed an EED-based, nanoscale, reversed phase (RP)LC-MS/MS platform, and demonstrated its ability to achieve complete structural elucidation of up to five structural isomers in a single LC-MS/MS analysis. [Figure not available: see fulltext.

  6. Dissociation mechanism of HNIW ions investigated by chemical ionization and electron impact mass spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Rongjie; Xiao, Hemiao [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China)

    2006-04-15

    Chemical Ionization (CI) with Collision-Induced Dissociation (CID) spectroscopy and Electron Impacting (EI) with metastable Mass analyzed Ion Kinetic Energy (MIKE) spectroscopy have been applied to study ionic dissociations of Hexanitrohexaazaisowurtzitane (HNIW). Similarities and differences between EI/MIKE and CI/CID mass spectra of HNIW were analyzed. In EI mass spectra, the ions [HNIW-n NO{sub 2}]{sup +} (n=2-5), such as the ion at m/z 347, were less frequent (1-2% relative abundance), but in CI mass spectra, these ions were very abundant. For some ions of large molar mass from HNIW, their dissociations pathways from parent ions to daughter ions were built according to CID and MIKE spectra. Molecular ions of HNIW with a protonated nitro group at five-member ring seem more stable than at six-member ring. The HNIW ions losing five of six nitro groups are very stable based on CID spectra, which agrees with some research results for thermal decomposition of HNIW in literature. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  7. Probing peptide fragment ion structures by combining sustained off-resonance collision-induced dissociation and gas-phase H/D exchange (SORI-HDX) in Fourier transform ion-cyclotron resonance (FT-ICR) instruments.

    Science.gov (United States)

    Somogyi, Arpád

    2008-12-01

    The usefulness of gas-phase H/D exchange is demonstrated to probe heterogeneous fragment and parent ion populations. Singly and multiply protonated peptides/proteins were fragmented by using sustained off-resonance irradiation collision-induced dissociation (SORI-CID). The fragments and the surviving precursor ions then all undergo H/D exchange in the gas-phase with either D(2)O or CD(3)OD under the same experimental conditions. Usually, 10 to 60 s of reaction time is adequate to monitor characteristic differences in the H/D exchange kinetic rates. These differences are then correlated to isomeric ion structures. The SORI-HDX method can be used to rapidly test fragment ion structures and provides useful insights into peptide fragmentation mechanisms.

  8. Structural Analysis of Unsaturated Glycosphingolipids Using Shotgun Ozone-Induced Dissociation Mass Spectrometry

    Science.gov (United States)

    Barrientos, Rodell C.; Vu, Ngoc; Zhang, Qibin

    2017-08-01

    Glycosphingolipids are essential biomolecules widely distributed across biological kingdoms yet remain relatively underexplored owing to both compositional and structural complexity. While the glycan head group has been the subject of most studies, there is paucity of reports on the lipid moiety, particularly the location of unsaturation. In this paper, ozone-induced dissociation mass spectrometry (OzID-MS) implemented in a traveling wave-based quadrupole time-of-flight (Q-ToF) mass spectrometer was applied to study unsaturated glycosphingolipids using shotgun approach. Resulting high resolution mass spectra facilitated the unambiguous identification of diagnostic OzID product ions. Using [M+Na]+ adducts of authentic standards, we observed that the long chain base and fatty acyl unsaturation had distinct reactivity with ozone. The reactivity of unsaturation in the fatty acyl chain was about 8-fold higher than that in the long chain base, which enables their straightforward differentiation. Influence of the head group, fatty acyl hydroxylation, and length of fatty acyl chain on the oxidative cleavage of double bonds was also observed. Application of this technique to bovine brain galactocerebrosides revealed co-isolated isobaric and regioisomeric species, which otherwise would be incompletely identified using contemporary collision-induced dissociation (CID) alone. These results highlight the potential of OzID-MS in glycosphingolipids research, which not only provides complementary structural information to existing CID technique but also facilitates de novo structural determination of these complex biomolecules. [Figure not available: see fulltext.

  9. An Unusual Family of Glycosylated Peptides Isolated from Dendroaspis angusticeps Venom and Characterized by Combination of Collision Induced and Electron Transfer Dissociation

    Science.gov (United States)

    Quinton, Loïc; Gilles, Nicolas; Smargiasso, Nicolas; Kiehne, Andrea; de Pauw, Edwin

    2011-11-01

    This study describes the structural characterization of a totally new family of peptides from the venom of the snake green mamba ( Dendroaspis angusticeps). Interestingly, these peptides differ in several points from other already known mamba toxins. First of all, they exhibit very small molecular masses, ranging from 1.3 to 2.4 kDa. The molecular mass of classical mamba toxins is in the range of 7 to 25 kDa. Second, the new peptides do not contain disulfide bonds, a post-translational modification commonly encountered in animal toxins. The third difference is the very high proportion of proline residues in the sequence accounting for about one-third of the sequence. Finally, these new peptides reveal a carbohydrate moiety, indicating a glycosylation in the sequence. The last two features have made the structural characterization of the new peptides by mass spectrometry a real analytical challenge. Peptides were characterized by a combined use of MALDI- TOF/TOF and nanoESI-IT-ETD experiments to determine not only the peptide sequence but also the composition and the position of the carbohydrate moiety. Anyway, such small glycosylated and proline-rich toxins are totally different from any other known snake peptide and form, as a consequence, a new family of peptides.

  10. Collision-Induced Dissociation of Deprotonated Peptides. Relative Abundance of Side-Chain Neutral Losses, Residue-Specific Product Ions, and Comparison with Protonated Peptides.

    Science.gov (United States)

    Liang, Yuxue; Neta, Pedatsur; Yang, Xiaoyu; Stein, Stephen E

    2018-03-01

    High-accuracy MS/MS spectra of deprotonated ions of 390 dipeptides and 137 peptides with three to six residues are studied. Many amino acid residues undergo neutral losses from their side chains. The most abundant is the loss of acetaldehyde from threonine. The abundance of losses from the side chains of other amino acids is estimated relative to that of threonine. While some amino acids lose the whole side chain, others lose only part of it, and some exhibit two or more different losses. Side-chain neutral losses are less abundant in the spectra of protonated peptides, being significant mainly for methionine and arginine. In addition to the neutral losses, many amino acid residues in deprotonated peptides produce specific negative ions after peptide bond cleavage. An expanded list of fragment ions from protonated peptides is also presented and compared with those of deprotonated peptides. Fragment ions are mostly different for these two cases. These lists of fragments are used to annotate peptide mass spectral libraries and to aid in the confirmation of specific amino acids in peptides. Graphical Abstract ᅟ.

  11. Collision-induced coherence

    International Nuclear Information System (INIS)

    Bloembergen, N.

    1985-01-01

    Collision-induced coherence is based on the elimination of phase correlations between coherent Feynman-type pathways which happen to interfere destructively in the absence of damping for certain nonlinear processes. One consequence is the appearance of the extra resonances in four-wave light mixing experiments, for which the intensity increases with increasing buffer gas pressure. These resonances may occur between a pair of initially unpopulated excited states, or between a pair of initially equally populated ground states. The pair of levels may be Zeeman substrates which became degenerate in zero magnetic field. The resulting collision-enhanced Hanle resonances can lead to very sharp variations in the four-wave light mixing signal as the external magnetic field passes through zero. The theoretical description in terms of a coherence grating between Zeeman substrates is equivalent to a description in terms of a spin polarization grating obtained by collision-enhanced transverse optical pumping. The axis of quantization in the former case is taken perpendicular to the direction of the light beams; in the latter case is taken parallel to this direction

  12. A review of electron-capture and electron-transfer dissociation tandem mass spectrometry in polymer chemistry

    International Nuclear Information System (INIS)

    Hart-Smith, Gene

    2014-01-01

    Graphical abstract: -- Highlights: •ECD and ETD can produce unique and diagnostically useful polymer ion fragmentation data. •The operating principles of ECD and ETD are discussed in relation to other dissociation techniques. •Key characteristics of ECD and ETD spectra, as observed from biological analytes, are discussed. •ECD and ETD analyses are compared to CID analyses for different classes of synthetic polymer. -- Abstract: Mass spectrometry (MS)-based studies of synthetic polymers often characterise detected polymer components using mass data alone. However when mass-based characterisations are ambiguous, tandem MS (MS/MS) offers a means by which additional analytical information may be collected. This review provides a synopsis of two particularly promising methods of dissociating polymer ions during MS/MS: electron-capture and electron-transfer dissociation (ECD and ETD, respectively). The article opens with a summary of the basic characteristics and operating principles of ECD and ETD, and relates these techniques to other methods of dissociating gas-phase ions, such as collision-induced dissociation (CID). Insights into ECD- and ETD-based MS/MS, gained from studies into proteins and peptides, are then discussed in relation to polymer chemistry. Finally, ECD- and ETD-based studies into various classes of polymer are summarised; for each polymer class, ECD- and ETD-derived data are compared to CID-derived data. These discussions identify ECD and ETD as powerful means by which unique and diagnostically useful polymer ion fragmentation data may be generated, and techniques worthy of increased utilisation by the polymer chemistry community

  13. Novel 2-Alkyl-1-Ethylpyridinium ionic liquids : synthesis, dissociation energies and volatility

    NARCIS (Netherlands)

    Vilas, M.; Alves da Rocha, M.A.; Fernandes, A.M.; Tojo, E.; Santos, L.M.N.B.F.

    2015-01-01

    This work presents the synthesis, volatility study and electrospray ionization mass spectrometry with energy-variable collision induced dissociation of the isolated [(cation)2(anion)]+ of a novel series of 2-alkyl-1-ethyl pyridinium based ionic liquids, [2CN-21C2Py][NTf2]. Compared to the

  14. Structure of [M + H − H2O]+ from Protonated Tetraglycine Revealed by Tandem Mass Spectrometry and IRMPD Spectroscopy

    NARCIS (Netherlands)

    Bythell, B. J.; Dain, Ryan P.; Curtice, Stephanie S.; Oomens, Jos; Steill, Jeffrey D.; Groenewold, Gary S.; la Paizs, Bé; van Stipdonk, M. J.

    2010-01-01

    Multiple-stage tandem mass spectrometry and collision-induced dissociation were used to investigate loss of H2O or CH3OH from protonated versions of GGGX (where X = G, A, and V), GGGGG, and the methyl esters of these peptides. In addition, wavelength-selective infrared multiple photon dissociation

  15. Collision-induced destructive quantum interference

    International Nuclear Information System (INIS)

    Yang Xihua; Sun Zhenrong; Zhang Shi'an; Ding Liang'en; Wang Zugeng

    2005-01-01

    We conduct theoretical studies on the collision-induced destructive quantum interference of two-colour two-photon transitions in an open rhomb-type five-level system with a widely separated doublet by the density matrix approach. The effects of the collision-induced decay rates, the ratio of the transition dipole moments and the energy separation of the doublet on the interference are analysed. It is shown that a narrow dip appears in the excitation spectrum due to the collision-induced destructive interference, and that the narrow interference dip still exists even when the collision broadening is comparable to the energy separation of the doublet. The physical origin of the collision-induced destructive quantum interference is analysed in the dressed-atom picture

  16. Molecular recognition: Comparative study of a tunable host-guest system by using a fluorescent model system and collision-induced dissociation mass spectrometry on dendrimers

    DEFF Research Database (Denmark)

    Pittelkow, M.; Nielsen, C.B.; Broeren, A.C.

    2005-01-01

    Host-guest interactions between the periphery of adamantylurea-functionalized dendrimers (host) and ureido acetic acid derivatives (guest) were shown to be specific, strong and spatially well-defined. The binding becomes stronger when using phosphonic or sulfonic acid derivatives. In the present...... work we have quantified the binding constants for the host-guest interactions between two different host motifs and six different guest molecules. The host molecules, which resemble the periphery of a poly(propylene imine) dendrimer, have been fitted with an anthracene-based fluorescent probe. The two...... host motifs differ in terms of the length of the spacer between a tertiary amine and two ureido functionalities. The guest molecules all contain an acidic moiety (either a carboxylic acid, a phosphonic acid, or a sulfonic acid) and three of them also contain an ureido moiety capable of forming multiple...

  17. Dipole and Coulomb forces in electron capture dissociation and electron transfer dissociation mass spectroscopy.

    Science.gov (United States)

    Świerszcz, Iwona; Skurski, Piotr; Simons, Jack

    2012-02-23

    Ab initio electronic structure calculations were performed on a doubly charged polypeptide model H(+)-Lys(Ala)(19)-CO-CH(NH(2))-CH(2)-SS-CH(2)-(NH(2))CH-CO-(Ala)(19)-Lys-H(+) consisting of a C-terminal protonated Lys followed by a 19-Ala α-helix with a 20th Ala-like unit whose side chain is linked by a disulfide bond to a corresponding Ala-like unit connected to a second 19-Ala α-helix terminated by a second C-terminal-protonated Lys. The Coulomb potentials arising from the two charged Lys residues and dipole potentials arising from the two oppositely directed 72 D dipoles of the α-helices act to stabilize the SS bond's σ* orbital. The Coulomb potentials provide stabilization of 1 eV, while the two large dipoles generate an additional 4 eV. Such stabilization allows the SS σ* orbital to attach an electron and thereby generate disulfide bond cleavage products. Although calculations are performed only on SS bond cleavage, discussion of N-C(α) bond cleavage caused by electron attachment to amide π* orbitals is also presented. The magnitudes of the stabilization energies as well as the fact that they arise from Coulomb and dipole potentials are supported by results on a small model system consisting of a H(3)C-SS-CH(3) molecule with positive and negative fractional point charges to its left and right designed to represent (i) two positive charges ca. 32 Å distant (i.e., the two charged Lys sites of the peptide model) and (ii) two 72 D dipoles (i.e., the two α-helices). Earlier workers suggested that internal dipole forces in polypeptides could act to guide incoming free electrons (i.e., in electron capture dissociation (ECD)) toward the positive end of the dipole and thus affect the branching ratios for cleaving various bonds. Those workers argued that, because of the huge mass difference between an anion donor and a free electron, internal dipole forces would have a far smaller influence over the trajectory of a donor (i.e., in electron transfer dissociation

  18. Differentiation of 2- and 6-isomers of (2-dimethylaminopropylbenzofuran by tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    V. A. Shevyrin

    2016-07-01

    Full Text Available Reliable identification of new psychoactive substances of 2-(2-methylaminopropylbenzofuran and 6-(2-methylaminopropylbenzofuran is problematic when analyzing by gas chromatography–mass spectrometry method. It found that these two isomers can be reliably differentiated by MS/MS spectra obtained by collision-induced dissociation of their protonated molecules.

  19. An ultra-sensitive instrument for collision activated dissociation mass spectrometry with high mass resolution

    International Nuclear Information System (INIS)

    Louter, G.J.

    1982-01-01

    During the last decade Collision Activated Dissociation Mass Spectrometry (CAD-MS) has developed into an important and sometimes unique technique for the structure elucidation of ions. An extensive description of the double stage MS is given, which has been especially devloped for CAD-MS. A high mass resolution and a very high sensitivity are obtained by application of special techniques like post-acceleration of fragment ions, quadrupole (Q-pole) lenses and an electro-optical, simultaneous ion detection system. The operation of the rather complex ion-optics is demonstrated by application of a computer simulation of the tandem MS. Special attention is given to the action of the four Q-pole lenses and the second sector magnet upon curvature and position of the mass focal plane. Two mass calibration methods are described for the fragment spectra. The so-called polynomial-method applies a fifth-order polynomial approximation of the functional relation between position on the detector and corresponding relative momentum of fragment ions. The second method uses the matrix model of the instrument. The detector consists of two channelplates (CEMA), a fibre optics slab, coated with a phosphor layer, a camera objective and a 1024-channels photodiode-array. A bio-chemical and an organic-chemical application of the instrument are given. As bio-chemical application the peak m/z 59 in the pyrolysis mass spectrum of complete mycobacteria is identified. As an example of organic-chemical application the fragmentation process of 2,3-butadienoic acid has been investigated. (Auth.)

  20. Systematic of the slope-mass-correlations in diffractive dissociation reactions

    International Nuclear Information System (INIS)

    Antunes, A.C.B.; Santoro, A.F.S.; Souza, M.H.G.

    1984-01-01

    A set of several results of the Three Components Deck Model for Diffractive Dissociation Reactions is presented. News and recently published results are summarized to obtain a general overview of the model, its predictions and comparison with experimental results. Two kinds of correlations and amplitudes are given: The slope-mass cos theta sup(GJ) correlation and slope-mass partial wave. (Author) [pt

  1. Low missing mass, single- and double diffraction dissociation at the LHC

    CERN Document Server

    Jenkovszky, Laszlo; Orava, Risto; Salii, Andrii

    2014-01-01

    Low missing mass, single- and double diffraction dissociation is calculated for the LHC energies from a dual-Regge model, dominated by a Pomeron Regge pole exchange. The model reproduces the rich resonance structure in the low missing mass Mx region. The diffractionly excited states lie on the nucleon trajectory, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single- and double diffraction dissociation in the kinematical range of present and future LHC measurements are given. The model predicts a possible turn-down of the cross section towards, t -> 0 in a region probably accessible in future experiments in the nearly forward direction. The present work is a continuation and extension (e.g. with double diffraction) of a previous work using the dual Regge approach.

  2. Automated and high confidence protein phosphorylation site localization using complementary collision-activated dissociation and electron transfer dissociation tandem mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, Thomas A; Sylvester, Marc; Jensen, Ole N

    2012-01-01

    -site localization and the number of assigned phospho-sites at a fixed false-localization rate. The average calculated Cscore from a large data set (>7000 phosphopeptide MS/MS spectra) was ∼32 compared to ∼23 and ∼17 for the Ascore using collision-activated dissociation (CAD) or electron transfer dissociation (ETD...... peptide fragmentation and the loss of labile phosphate groups complicate identification of the site of the phosphate motif. Here, we have implemented and evaluated a novel approach for phospho-site localization by the combined use of peptide tandem mass spectrometry data obtained using both collision......-activated dissociation and electron transfer dissociation, an approach termed the Cscore. The scoring algorithm used in the Cscore was adapted from the widely used Ascore method. The analytical benefit of integrating the product ion information of both ETD and CAD data are evident by increased confidence in phospho...

  3. Collision induced fragmentation of fast molecular ions in solids and gases

    International Nuclear Information System (INIS)

    Gemmell, D.S.

    1979-01-01

    A brief review is given of recent high resolution measurements on fragments arising from the collision-induced dissociation of fast (MeV) molecular ions. For solid targets, strong wake effects are observed. For gaseous targets, excited electronic states of the projectile ions play an important role. Measurements of this type provide useful information on the charge states of fast ions traversing matter. The experimental techniques show promise as a unique method for determining the geometrical structures of the molecular-ion projectiles. 41 references

  4. Hypoxia, Radiosensitizers and high-LET radiation - Nimorazole fragmentation using mass spectrometry

    DEFF Research Database (Denmark)

    Feketeova, Linda; Bassler, Niels

    (s): Fragmentation experiments have been performed using a Finnigan- LTQ-FT mass spectrometer equipped with an electrospray ionisation source. Collision-induced dissociation (CID) and electron-induced dissociation (EID) have been carried out by mass selecting the desired ions and subjecting them to activation energy...... using mass spectrometry. Understanding the fragmentation of radiosensitizers is crucial in evaluating the radiosensitization potential and developing new and more effective drugs, which may improve TCP in hypoxic tumours when using ion beams such as carbon-12 along with LET-painting techniques. Method...

  5. Heat-and-mass transfer during a laminar dissociating gas flow in eccentric annular channels

    International Nuclear Information System (INIS)

    Besedina, T.V.; Udot, A.V.; Yakushev, A.P.

    1987-01-01

    An algorithm to calculate heat-and-mass transfer processes during dissociating gas laminar flow in an eccentric annular channels is considered. Analytical solutions of the heat transfer equations for a rod clodding and gap with boundary conditions of conjugation of temperatures and heat fluxes have been used to determine temperature field. This has made it possible to proceed from slution of the conjugate problem to solution of the equation of energy only for the coolant. The results of calculation of temperature distribution along the cladding for different values of its eccentricity and thermal conductivity coefficient both for the case of frozen flow and in the presence of chemical reactions in the flow are given. When calculating temperatures with conjugation boundary conditions temperature gradients in azimuthal direction are far less and heat transfer in concentration diffusion is carried out mainly in radial direction

  6. Dissociative ionization of methanol in medium intense femtosecond laser field using time-of-flight mass spectrometry

    Science.gov (United States)

    Elshakre, Mohamed

    2015-07-01

    800 nm 100 fs laser combined with TOF mass spectrometer was used to investigate the dissociative ionization of methanol, CH3OH in the laser intensity less than 4×1013 W/cm2. The results showed that the dissociation follows a sequential step-wise dissociation pattern, with no sign for Coulomb explosion. At very low intensity 1.4×1013 W/cm2, only the parent ion CH3OH+ appears. At 1.7×1013 W/cm2, the dissociation products are mainly due to hydrogen elimination from the O-H or C-H bonds forming CH3O+ and CH2OH+ primary ions. At 2.0×1013 W/cm2, the C-O bond starts to break forming CH3+, which simultaneously dissociates to CH2+. The primary fragment ions CH3O+ and CH2OH+ start to dissociate into lower secondary fragments as CH2O+ and CHO+ for the former and CHOH+ and COH+ for the latter. At 2.8×1013 W/cm2, secondary dissociation fragments dominate the spectrum including C+, CH+, CH2+, OH+, and O+ and the H+ is detected. At 3.0×1013W/cm2, H2+ is detected. For all ions formed, the ion yield increases with laser intensity till it reaches maximum, after which it drops down manifesting the dissociation of these ions into smaller fragments. Among all ions, only H+ was found to have angular anisotropic distribution.

  7. Collision induced fragmentation dynamics of small metallic clusters; Dynamique de fragmentation induite par collision de petits agregats metalliques

    Energy Technology Data Exchange (ETDEWEB)

    Picard, Y

    1999-04-15

    The goal of this work is the complete analysis of the fragmentation of alkali clusters (Na{sub n}{sup +} (n < 10), NaK{sup +} and K{sub 2}{sup +}) induced by collision with light atomic (He) or molecular (H{sub 2}) targets. The main point is to study how the energy is transmitted to the cluster during the collision and how this energy is shared among the various degrees of freedom of the system and leads to its fragmentation. Two types of interactions govern the collision induced dissociation processes: on one hand, the electronic mechanisms where the target perturbs the electronic cloud and brings the molecule into a dissociative state, and on the other hand, the impulsive mechanisms where the momentum transferred to the atomic cores leads to the rotational-vibrational dissociation of the molecule. The experimental procedure is based on the measurement of the velocity vectors of the outgoing fragments detected in coincidence. This allows to reconstruct the full kinematics of the fragmentation and to separate and characterize for the first time the two types of interactions. The two basic mechanisms of collision induced dissociation are then clearly resolved for the diatomic molecule Na{sub 2}{sup +}. For the heteronuclear molecular ion NaK{sup +}, it is shown that the dissociation process is due to a combination of electronic and impulsive mechanisms in some of the dissociation pathways. The extension to the study of metallic clusters Na{sub n}{sup +} (n < 10) fragmentation shows the role and the relative importance of the electronic and impulsive mechanisms and their evolution with the cluster size. The complete analysis of Na{sub 3}{sup +} multi-fragmentation is also presented. (author)

  8. Increasing the productivity of glycopeptides analysis by using higher-energy collision dissociation-accurate mass-product-dependent electron transfer dissociation.

    Science.gov (United States)

    Saba, Julian; Dutta, Sucharita; Hemenway, Eric; Viner, Rosa

    2012-01-01

    Currently, glycans are attracting attention from the scientific community as potential biomarkers or as posttranslational modifications (PTMs) of therapeutic proteins. However, structural characterization of glycoproteins and glycopeptides remains analytically challenging. Here, we report on the implementation of a novel acquisition strategy termed higher-energy collision dissociation-accurate mass-product-dependent electron transfer dissociation (HCD-PD-ETD) on a hybrid linear ion trap-orbitrap mass spectrometer. This acquisition strategy uses the complementary fragmentations of ETD and HCD for glycopeptides analysis in an intelligent fashion. Furthermore, the approach minimizes user input for optimizing instrumental parameters and enables straightforward detection of glycopeptides. ETD spectra are only acquired when glycan oxonium ions from MS/MS HCD are detected. The advantage of this approach is that it streamlines data analysis and improves dynamic range and duty cycle. Here, we present the benefits of HCD-PD-ETD relative to the traditional alternating HCD/ETD for a trainer set containing twelve-protein mixture with two glycoproteins: human serotransferrin, ovalbumin and contaminations of two other: bovine alpha 1 acid glycoprotein (bAGP) and bovine fetuin.

  9. Stimulation of Slack K+ channels alters mass at the plasma membrane by triggering dissociation of a phosphatase-regulatory complex

    Science.gov (United States)

    Fleming, Matthew R.; Brown, Maile R.; Kronengold, Jack; Zhang, Yalan; Jenkins, David P.; Barcia, Gulia; Nabbout, Rima; Bausch, Anne E.; Ruth, Peter; Lukowski, Robert; Navaratnam, Dhasakumar S.; Kaczmarek, Leonard K.

    2016-01-01

    Summary Human mutations in the cytoplasmic C-terminal domain of Slack sodium-activated potassium (KNa) channels result in childhood epilepsy with severe intellectual disability. Slack currents can be increased by pharmacological activators or by phosphorylation of a Slack C-terminal residue by protein kinase C. Using an optical biosensor assay, we find that Slack channel stimulation in neurons or transfected cells produces loss of mass near the plasma membrane. Slack mutants associated with intellectual disability fail to trigger any change in mass. The loss of mass results from the dissociation of the protein phosphatase 1 (PP1) targeting protein, Phactr-1, from the channel. Phactr1 dissociation is specific to wild-type Slack channels and is not observed when related potassium channels are stimulated. Our findings suggest that Slack channels are coupled to cytoplasmic signaling pathways, and that dysregulation of this coupling may trigger the aberrant intellectual development associated with specific childhood epilepsies. PMID:27545877

  10. Stimulation of Slack K+ Channels Alters Mass at the Plasma Membrane by Triggering Dissociation of a Phosphatase-Regulatory Complex

    Directory of Open Access Journals (Sweden)

    Matthew R. Fleming

    2016-08-01

    Full Text Available Human mutations in the cytoplasmic C-terminal domain of Slack sodium-activated potassium (KNa channels result in childhood epilepsy with severe intellectual disability. Slack currents can be increased by pharmacological activators or by phosphorylation of a Slack C-terminal residue by protein kinase C. Using an optical biosensor assay, we find that Slack channel stimulation in neurons or transfected cells produces loss of mass near the plasma membrane. Slack mutants associated with intellectual disability fail to trigger any change in mass. The loss of mass results from the dissociation of the protein phosphatase 1 (PP1 targeting protein, Phactr-1, from the channel. Phactr1 dissociation is specific to wild-type Slack channels and is not observed when related potassium channels are stimulated. Our findings suggest that Slack channels are coupled to cytoplasmic signaling pathways and that dysregulation of this coupling may trigger the aberrant intellectual development associated with specific childhood epilepsies.

  11. Dissociative electron attachment negative ion mass spectrometry: a chlorine-specific detector for gas chromatography

    Science.gov (United States)

    Curtis, Jonathan M.; Boyd, Robert K.

    1997-11-01

    This work describes the application of negative ion chemical ionization, optimized for dissociative electron attachment (DEA), to location of unknown trace chlorinated compounds in complex gas chromatograms by selected ion recording (SIR) of m / z 35 and 37. The DEA-SIR technique is compared with other GC detectors, including the electron capture detector, electrolytic conductivity detector, the atomic emission detector and the chemical reaction interface mass spectrometry method, with respect to selectivity for chlorine, sensitivity, linear dynamic range, and general robustness and ease of use. When applied to quantitative analysis of target analytes such as polychlorobiphenyls, the DEA-SIR method has potential problems arising from the possibility of suppression effects due to abundant co-eluting components, and possible alleviating measures are discussed. In addition to these practical investigations, literature information on the fundamental physical and chemical phenomena underlying the DEA process is summarized in order to guide future work on extension to other compound types and on general improvements to the technique.

  12. Dissociation dynamics of methylal

    Energy Technology Data Exchange (ETDEWEB)

    Beaud, P; Frey, H -M; Gerber, T; Mischler, B; Radi, P P; Tzannis, A -P [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The dissociation of methylal is investigated using mass spectrometry, combined with a pyrolytic radical source and femtosecond pump probe experiments. Based on preliminary results two reaction paths of methylal dissociation are proposed and discussed. (author) 4 fig., 3 refs.

  13. Enhancing Protein Disulfide Bond Cleavage by UV Excitation and Electron Capture Dissociation for Top-Down Mass Spectrometry

    OpenAIRE

    Wongkongkathep, Piriya; Li, Huilin; Zhang, Xing; Loo, Rachel R. Ogorzalek; Julian, Ryan R.; Loo, Joseph A.

    2015-01-01

    The application of ion pre-activation with 266 nm ultraviolet (UV) laser irradiation combined with electron capture dissociation (ECD) is demonstrated to enhance top-down mass spectrometry sequence coverage of disulfide bond containing proteins. UV-based activation can homolytically cleave a disulfide bond to yield two separated thiol radicals. Activated ECD experiments of insulin and ribonuclease A containing three and four disulfide bonds, respectively, were performed. UV-activation in comb...

  14. A new time of flight mass spectrometer for absolute dissociative electron attachment cross-section measurements in gas phase

    Science.gov (United States)

    Chakraborty, Dipayan; Nag, Pamir; Nandi, Dhananjay

    2018-02-01

    A new time of flight mass spectrometer (TOFMS) has been developed to study the absolute dissociative electron attachment (DEA) cross section using a relative flow technique of a wide variety of molecules in gas phase, ranging from simple diatomic to complex biomolecules. Unlike the Wiley-McLaren type TOFMS, here the total ion collection condition has been achieved without compromising the mass resolution by introducing a field free drift region after the lensing arrangement. The field free interaction region is provided for low energy electron molecule collision studies. The spectrometer can be used to study a wide range of masses (H- ion to few hundreds atomic mass unit). The mass resolution capability of the spectrometer has been checked experimentally by measuring the mass spectra of fragment anions arising from DEA to methanol. Overall performance of the spectrometer has been tested by measuring the absolute DEA cross section of the ground state SO2 molecule, and the results are satisfactory.

  15. Identification of isomers and control of ionization and dissociation processes using dual-mass-spectrometer scheme and genetic algorithm optimization

    International Nuclear Information System (INIS)

    Chen Zhou; Qiu-Nan Tong; Zhang Cong-Cong; Hu Zhan

    2015-01-01

    Identification of acetone and its two isomers, and the control of their ionization and dissociation processes are performed using a dual-mass-spectrometer scheme. The scheme employs two sets of time of flight mass spectrometers to simultaneously acquire the mass spectra of two different molecules under the irradiation of identically shaped femtosecond laser pulses. The optimal laser pulses are found using closed-loop learning method based on a genetic algorithm. Compared with the mass spectra of the two isomers that are obtained with the transform limited pulse, those obtained under the irradiation of the optimal laser pulse show large differences and the various reaction pathways of the two molecules are selectively controlled. The experimental results demonstrate that the scheme is quite effective and useful in studies of two molecules having common mass peaks, which makes a traditional single mass spectrometer unfeasible. (paper)

  16. Computation of Collision-Induced Absorption by Simple Molecular Complexes, for Astrophysical Applications

    Science.gov (United States)

    Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

    2012-06-01

    The interaction-induced absorption by collisional pairs of H{_2} molecules is an important opacity source in the atmospheres of various types of planets and cool stars, such as late stars, low-mass stars, brown dwarfs, cool white dwarf stars, the ambers of the smaller, burnt out main sequence stars, exoplanets, etc., and therefore of special astronomical interest The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H{_2}-H{_2}, H{_2}-He, and H{_2}-H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin. Laboratory measurements of interaction-induced absorption spectra by H{_2} pairs exist only at room temperature and below. We show that our results reproduce these measurements closely, so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures. First results for H_2-He complexes have already been applied to astrophysical models have shown great improvements in these models. L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 X. Li, K. L. C. Hunt, F. Wang, M. Abel, and L. Frommhold, Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin, Int. J. of Spect., vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201 M. Abel, L. Frommhold, X. Li, and K. L. C. Hunt, Collision-induced absorption by H{_2} pairs: From hundreds to thousands of Kelvin, J. Phys. Chem. A, 115, 6805-6812, 2011} L. Frommhold, M. Abel, F. Wang, M. Gustafsson, X. Li, and K. L. C. Hunt, "Infrared atmospheric emission and absorption by simple molecular complexes, from first principles", Mol. Phys. 108, 2265, 2010 M. Abel, L. Frommhold, X. Li, and K. L. C. Hunt, Infrared absorption by collisional H_2-He complexes

  17. Wavepacket theory of collisional dissociation in molecules

    International Nuclear Information System (INIS)

    Kulander, K.

    1980-01-01

    An explicit integration scheme is used to solve the time dependent Schroedinger equation for wavepackets which model collisions in the collinear H + H 2 system. A realistic LEPS-type potential energy surface is used. Collision energies considered are above the dissociation threshold and probabilities for collision induced dissociation are reported. Also quantum mechanical state-to-state transition probabilities are generated. These results are compared to extensive classical trajectory calculations performed on this same system. The time evolution of the wavepacket densities is studied to understand the dynamics of the collinear collisional dissociation process

  18. Multi-property isotropic intermolecular potentials and predicted spectral lineshapes of collision-induced absorption (CIA), collision-induced light scattering (CILS) and collision-induced hyper-Rayleigh scattering (CIHR) for H2sbnd Ne, -Kr and -Xe

    Science.gov (United States)

    El-Kader, M. S. A.; Godet, J.-L.; Gustafsson, M.; Maroulis, G.

    2018-04-01

    Quantum mechanical lineshapes of collision-induced absorption (CIA), collision-induced light scattering (CILS) and collision-induced hyper-Rayleigh scattering (CIHR) at room temperature (295 K) are computed for gaseous mixtures of molecular hydrogen with neon, krypton and xenon. The induced spectra are detected using theoretical values for induced dipole moment, pair-polarizability trace and anisotropy, hyper-polarizability and updated intermolecular potentials. Good agreement is observed for all spectra when the literature and the present potentials which are constructed from the transport and thermo-physical properties are used.

  19. Hemoglobin variants as models for investigation of dissociation of intact polypeptide chains by ESI tandem mass spectrometry

    International Nuclear Information System (INIS)

    Light, K.J.; Loo, J.A.; Edmonds, C.G.; Smith, R.D.

    1991-06-01

    Electrospray ionization mass spectroscopy (ESI-MS) is rapidly becoming a practical biochemical tool for peptide and protein sequence analysis. The utility of ESI-MS is through use of Collisionally Activated Dissociation (ESI-CAD-MS). Human hemoglobin (Hb, ∼62 kDa) consists of four polypeptide chains and a prosthetic heme group. There are over 400 Hb variants, characterized by amino acid substitutions in either the alpha or beta polypeptide chains. We investigated ESI-CAD-MS as a tool for rapidly analyzing amino acid substitutions, using eight Hb beta chain variants. The approximate location of the modification can be deduced from comparison of the CAD mass spectra and observance of the mass shifts of the fragment ion containing the substitution. Fragmentation occurs preferentially at the amino terminus of proline residues. For most substitutions, differences in CAD mass spectra were not seen. 2 figs

  20. Low mass diffractive dissociation in a simple t-dependent dual bootstrap model

    International Nuclear Information System (INIS)

    Bishari, M.

    1978-08-01

    The smallness of inelastic diffractive dissociation is explicitly demonstrated, in the framework of the '1/N dual unitarization' scheme, by incorporating a Deck type mechanism with the crucial planar bootstrap equation. Although both inelastic and elastic pomeron couplings are of the same order in 1/N, the origin for their smallness, however, is not identical. (author)

  1. Dissociative diffusion mechanism in vacancy-rich materials according to mass action kinetics

    Directory of Open Access Journals (Sweden)

    N. J. Biderman

    2016-05-01

    Full Text Available Two sets of diffusion-reaction numerical simulations using a finite difference method (FDM were conducted to investigate fast impurity diffusion via interstitial sites in vacancy-rich materials such as Cu(In,GaSe2 (CIGS and Cu2ZnSn(S, Se4 (CZTSSe or CZTS via the dissociative diffusion mechanism where the interstitial diffuser ultimately reacts with a vacancy to produce a substitutional. The first set of simulations extends the standard interstitial-limited dissociative diffusion theory to vacancy-rich material conditions where vacancies are annihilated in large amounts, introducing non-equilibrium vacancy concentration profiles. The second simulation set explores the vacancy-limited dissociative diffusion where impurity incorporation increases the equilibrium vacancy concentration. In addition to diffusion profiles of varying concentrations and shapes that were obtained in all simulations, some of the profiles can be fitted with the constant- and limited-source solutions of Fick’s second law despite the non-equilibrium condition induced by the interstitial-vacancy reaction. The first set of simulations reveals that the dissociative diffusion coefficient in vacancy-rich materials is inversely proportional to the initial vacancy concentration. In the second set of numerical simulations, impurity-induced changes in the vacancy concentration lead to distinctive diffusion profile shapes. The simulation results are also compared with published data of impurity diffusion in CIGS. According to the characteristic properties of diffusion profiles from the two set of simulations, experimental detection of the dissociative diffusion mechanism in vacancy-rich materials may be possible.

  2. Collision induced light-scattering from gaseous sulphurhexafluoride

    International Nuclear Information System (INIS)

    Pleich, R.

    1983-10-01

    Modern laser technology permits the measurement of collision induced light-scattering spectra from molecular gases at low densities. Measurements of this type provide a test for the separation dependent pair polarizabilities and pair potentials. For this work the octahedral molecule sulphurhexafluoride (SF 6 , point group symmetry 0sub(h)) has been chosen for which the permanent polarizability anisotropy vanishes. For the experiment an argon ion laser in combination with a double grating monochromator and standard photon counting techniques were used. Both the polarized and depolarized scattering cross sections were obtained. The point dipole-induced-dipole (DID) effect is shown to account for the most of the total scattered intensity. At low frequency shifts the line shape of the SF 6 spectrum is dominated by bound dimers, whereas the intermediate frequency range up to 50 cm -1 is well described by a DID free trajectory binary collision model. The high frequency wings are discussed in terms of the collision induced rotational Raman (CIRR) effect and estimates for the dipole-octopole polarizability E are obtained both from the spectral distribution and from the depolarization ratio. It is demonstrated that the hierarchy of effects constituting the CIRR-model converges slowly for large frequency shifts. (Author)

  3. Stimulation of Slack K(+) Channels Alters Mass at the Plasma Membrane by Triggering Dissociation of a Phosphatase-Regulatory Complex.

    Science.gov (United States)

    Fleming, Matthew R; Brown, Maile R; Kronengold, Jack; Zhang, Yalan; Jenkins, David P; Barcia, Gulia; Nabbout, Rima; Bausch, Anne E; Ruth, Peter; Lukowski, Robert; Navaratnam, Dhasakumar S; Kaczmarek, Leonard K

    2016-08-30

    Human mutations in the cytoplasmic C-terminal domain of Slack sodium-activated potassium (KNa) channels result in childhood epilepsy with severe intellectual disability. Slack currents can be increased by pharmacological activators or by phosphorylation of a Slack C-terminal residue by protein kinase C. Using an optical biosensor assay, we find that Slack channel stimulation in neurons or transfected cells produces loss of mass near the plasma membrane. Slack mutants associated with intellectual disability fail to trigger any change in mass. The loss of mass results from the dissociation of the protein phosphatase 1 (PP1) targeting protein, Phactr-1, from the channel. Phactr1 dissociation is specific to wild-type Slack channels and is not observed when related potassium channels are stimulated. Our findings suggest that Slack channels are coupled to cytoplasmic signaling pathways and that dysregulation of this coupling may trigger the aberrant intellectual development associated with specific childhood epilepsies. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Energy and mass-number dependence of the dissociation temperature in hydrodynamical models

    International Nuclear Information System (INIS)

    Hama, Y.; Navarra, F.S.

    1990-10-01

    Transverse-momentum distributions of π and K have been analysed to obtain the √s dependence of the collective transverse and the dissociation temperature in pp- and p-barp induced multiparticle production reactions. A good fit of both the pion and kaon data has been obtained in terms of a previously proposed simple parametrization of the collective transverse rapidity distribution. The main outcomes are the logarithmically increasing average transverse rapidity squared and a slowly decreasing dissociation temperature T sub(d) as the incident energy √s increases. This last behaviour is in excellent agreement with early Landau's estimate. An extension of the same estimate to nucleus-nucleus collisions gives the correct low temperature component which has been observed in heavy-ion experiments. (author)

  5. Surface-Induced Dissociation of Protein Complexes in a Hybrid Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Jing; Zhou, Mowei; Gilbert, Joshua D.; Wolff, Jeremy J.; Somogyi, Árpád; Pedder, Randall E.; Quintyn, Royston S.; Morrison, Lindsay J.; Easterling, Michael L.; Paša-Tolić, Ljiljana; Wysocki, Vicki H.

    2017-01-03

    Mass spectrometry continues to develop as a valuable tool in the analysis of proteins and protein complexes. In protein complex mass spectrometry studies, surface-induced dissociation (SID) has been successfully applied in quadrupole time-of-flight (Q-TOF) instruments. SID provides structural information on non-covalent protein complexes that is complementary to other techniques. However, the mass resolution of Q-TOF instruments can limit the information that can be obtained for protein complexes by SID. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) provides ultrahigh resolution and ultrahigh mass accuracy measurements. In this study, an SID device was designed and successfully installed in a hybrid FT-ICR instrument in place of the standard gas collision cell. The SID-FT-ICR platform has been tested with several protein complex systems (homooligomers, a heterooligomer, and a protein-ligand complex, ranging from 53 kDa to 85 kDa), and the results are consistent with data previously acquired on Q-TOF platforms, matching predictions from known protein interface information. SID fragments with the same m/z but different charge states are well-resolved based on distinct spacing between adjacent isotope peaks, and the addition of metal cations and ligands can also be isotopically resolved with the ultrahigh mass resolution available in FT-ICR.

  6. A qualitative study of amlodipine and its related compounds by electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Gibbons, John; Pugh, Jonathan; Dimopoulos-Italiano, Gina; Pike, Richard

    2006-01-01

    A comprehensive structural analysis of amlodipine and certain related compounds was performed by electrospray ionization tandem mass spectrometry. Triple quadrupole and quadrupole time-of-flight instruments were used to provide collision-induced dissociation and accurate mass measurement for selected product and second-generation product ions. A unique ion rearrangement was observed, which was found to be characteristic of certain dihydropyridines. This study provides a fundamental understanding of the fragmentation of these compounds. The structural elucidation of an unknown impurity is presented as an example. Copyright (c) 2006 John Wiley & Sons, Ltd.

  7. Collision-induced polarizabilities of inert gas atoms

    International Nuclear Information System (INIS)

    Clarke, K.L.; Madden, P.A.; Buckingham, A.D.

    1978-01-01

    The use of polarizability densities to calculate collision-induced polarizabilities is investigated. One method for computing polarizabilities of inert gas diatoms employs atomic polarizability densities from finite-field Hartree-Fock calculations, together with classical equations for the polarization of dielectrics. It is shown that this model gives inaccurate values for both the local fields and the local response to non-uniform fields. An alternative method incorporating the same physical effects is used to compute the pair polarizabilities to first order in the interatomic interaction. To first order the pair contribution to the trace of the polarizability is negative at short range. The calculated anisotropy does not differ significantly from the DID value, whereas the polarizability density calculation gives a substantial reduction in the anisotropy. (author)

  8. Correlation diagram approach to the dissociative ionization mechanisms of methanol

    International Nuclear Information System (INIS)

    Momigny, J.; Wankenne, H.; Krier, C.

    1980-01-01

    A systematic survey is made of the dissociation processes from the ground state and from the electronically excited states of CH 3 OH + . Most metastable processes occurring in the mass spectrum of CD 3 OH are studied also, including measurement of the kinetic energy release and appearance potentials. It is shown that if ionic species such as CH 2 OH + , CH 2 O + and HCO + are present in the mass spectrum of CH 3 OH, the isomers CH 3 O + , HCOH + and COH + are also present. The precursors of these ions having been identified by the metastable processes, correlation diagrams are used to show that, from the first ionization potential of CH 3 OH to 14 eV, the only exception being CH 3 O + which results from an electronically spin-forbidden predissociation, the fragment ions can be considered to result from adiabatic decay of the ground state of CH 3 OH + . The potential barriers involved in these adiabatic processes result either from conical intersection or from avoided-crossing between the ground state of CH 3 OH + and the electronically excited states occurring up to 14 eV. At higher energies, many non-adiabatic processes occur; for example, the appearance of CD 2 O + and the electronically excited states of HCO + and COH + ions. It is shown additionally that kinetic energy releases observed in the collision-induced processes CH 3 OH + → CH 2 OH + + H and CH 2 OH + → HCO + + H 2 are in good agreement with the mechanistic approach via the correlation diagram for the appearance of the non-collision-induced ion processes. (orig.)

  9. Quark-diquark fragmentation in 'high mass' diffraction dissociation in proton-proton collisions at 360 GeV/c

    International Nuclear Information System (INIS)

    Asai, Makoto

    1986-01-01

    Using the European Hybrid spectrometer (EHS) system, we have investigated the properties of the four-prong 'high mass' diffraction dissociation process in the exclusive processes pp → pX, where X represents pπ + π - nπ 0 (n = 0, 1, 2). We present experimental evidences that Pomeron couples with a single valence quark in the incident proton and that the other two valence quarks in the proton behaves as the spectator diquark. We also show that most of the baryons are produced from the spectator diquark system in these processes. The p t suppression is also shown in the Gottfried-Jackson frame, the frame in which the excited system composed of Pomeron and the incident proton is at rest. Characteristic features in the hadronization of this process are very much similar to those of quark-diquark fragmentation in lepton-hardron deep inelastic scattering. (author)

  10. Dynamical and topological considerations in low and high mass diffractive dissociation

    International Nuclear Information System (INIS)

    Bishari, M.

    1978-01-01

    The topological structure of a given process completely specifies the 1/N dependence. However dynamics seems to be crucial in characterizing strongly interacting reactions, as illustrated in the study of elastic scattering, low mass diffraction and the triple pomeron mechanism. The ''1/N dual unitarization'' scheme is a viable framework for Gribov's Reggeon field theory, since it clarifies and determines the bare parameters of Gribov's Lagrangian. (author)

  11. Hormone replacement therapy dissociates fat mass and bone mass, and tends to reduce weight gain in early postmenopausal women

    DEFF Research Database (Denmark)

    Jensen, L B; Vestergaard, P; Hermann, A P

    2003-01-01

    in women randomized to HRT (1.94 +/- 4.86 kg) than in women randomized to no HRT (2.57 +/- 4.63, p = 0.046). A similar pattern was seen in the group receiving HRT or not by their own choice. The smaller weight gain in women on HRT was almost entirely caused by a lesser gain in fat. The main determinant...... of the weight gain was a decline in physical fitness. Women opting for HRT had a significantly lower body weight at inclusion than the other participants, but the results in the self-selected part of the study followed the pattern found in the randomized part. The change in fat mass was the strongest predictor...... of bone changes in untreated women, whereas the change in lean body mass was the strongest predictor when HRT was given. Body weight increases after the menopause. The gain in weight is related to a decrease in working capacity. HRT is associated with a smaller increase in fat mass after menopause. Fat...

  12. Protein hydrogen exchange measured at single-residue resolution by electron transfer dissociation mass spectrometry

    DEFF Research Database (Denmark)

    Rand, Kasper D; Zehl, Martin; Jensen, Ole Nørregaard

    2009-01-01

    Because of unparalleled sensitivity and tolerance to protein size, mass spectrometry (MS) has become a popular method for measuring the solution hydrogen (1H/2H) exchange (HX) of biologically relevant protein states. While incorporated deuterium can be localized to different regions by pepsin....... The deuterium labeling pattern of beta2-microglobulin is retained in the gaseous fragment ions by employing mild declustering conditions for electrospray ionization. A recently developed model peptide is used to arrive at such ion source declustering conditions that prevent the occurrence of intramolecular gas...

  13. Heat mass transfer in turbulent flow of dissociating N2O4 in a channel of complex geometry

    International Nuclear Information System (INIS)

    Nesterenko, V.B.; Tverkovkin, B.E.; Yakushev, A.P.; Mikryukova, T.I.

    1976-01-01

    The processes of heat and mass transfer at turbulent flow of the N 2 O 4 -dissociating gas along the bundles of fuel elements are investigated. A numerical solution has been obtained by the method of variable directions with the second-order boundary conditions in the following range of parameters: Reinolds number, Re=(0.12-1.73)x10 5 ; pressure, p=45-170 bar; a relative spacing between rods, t=1.05; 1.1; and the gsub(e)rsub(0)/Λsub(f)=(0.2-1.44)x10 5 , where qsub(e) is a specific thermal flux on the rod surface; rsub(0) - a rod radius; Λsub(f)-thermal conductivity of the coolant. The coolant temperature at channel inlet is 450 deg K. Temperature and concentration fields of the O 2 -component are obtained. The effect of pressure on the distribution of temperatures and concentrations of the O 2 -component and their non-uniformity over a perimeter are investigated. The distributions average Nusselt numbers over the channel length versus the pressure of a gaseous mixture are obtained. A significant effect of chemical reactions on heat transfer in the channel of a complicated form is shown

  14. Mass spectrometric determination of enthalpies of dissociation of gaseous complex fluorides into neutral and charged particles. Pt. 3

    International Nuclear Information System (INIS)

    Sidorov, L.N.; Skokan, E.V.; Nikitin, M.I.; Sorokin, I.D.

    1980-01-01

    Mass spectrometry is used to study ion-molecule equilibria in the saturated vapours of the two-component systems MF-UF 4 (where M is Na or K), containing the negative ions F - , UF - 5 and UF - 6 . The electron affinities of UF 5 and UF 6 are determined as 3.3 +- 0.16 eV and 4.89 +- 0.25 eV and the heats of the following reactions are: F - + UF 4 → UF - 5 ΔH 0 1100 = -98,0 +- 0.3 kcal mol -1 (-410.0 +- 1.3 kJ mol -1 ), AlF 3 + UF - 5 → AlF - 4 + UF 4 ΔH 0 1100 = -22.3 +- 0.3 kcal mol -1 (-93.3 +- 1.3 kJ mol -1 ), UF 5 + UF - 5 → UF 4 + UF - 6 ΔH 0 1087 = -3.4 +- 0.2 kcal mol -1 (-14.2 +- 0.8 kJ mol -1 ). These data and literature values are used to calculate the heat of formation of the UF - 5 ion and the heats of dissociation of the alkali metal fluorouranates into neutral and charged particles. (orig.)

  15. Enhancing Protein Disulfide Bond Cleavage by UV Excitation and Electron Capture Dissociation for Top-Down Mass Spectrometry.

    Science.gov (United States)

    Wongkongkathep, Piriya; Li, Huilin; Zhang, Xing; Loo, Rachel R Ogorzalek; Julian, Ryan R; Loo, Joseph A

    2015-11-15

    The application of ion pre-activation with 266 nm ultraviolet (UV) laser irradiation combined with electron capture dissociation (ECD) is demonstrated to enhance top-down mass spectrometry sequence coverage of disulfide bond containing proteins. UV-based activation can homolytically cleave a disulfide bond to yield two separated thiol radicals. Activated ECD experiments of insulin and ribonuclease A containing three and four disulfide bonds, respectively, were performed. UV-activation in combination with ECD allowed the three disulfide bonds of insulin to be cleaved and the overall sequence coverage to be increased. For the larger sized ribonuclease A with four disulfide bonds, irradiation from an infrared laser (10.6 µm) to disrupt non-covalent interactions was combined with UV-activation to facilitate the cleavage of up to three disulfide bonds. Preferences for disulfide bond cleavage are dependent on protein structure and sequence. Disulfide bonds can reform if the generated radicals remain in close proximity. By varying the time delay between the UV-activation and the ECD events, it was determined that disulfide bonds reform within 10-100 msec after their UV-homolytic cleavage.

  16. Peptides derivatized with bicyclic quaternary ammonium ionization tags. Sequencing via tandem mass spectrometry.

    Science.gov (United States)

    Setner, Bartosz; Rudowska, Magdalena; Klem, Ewelina; Cebrat, Marek; Szewczuk, Zbigniew

    2014-10-01

    Improving the sensitivity of detection and fragmentation of peptides to provide reliable sequencing of peptides is an important goal of mass spectrometric analysis. Peptides derivatized by bicyclic quaternary ammonium ionization tags: 1-azabicyclo[2.2.2]octane (ABCO) or 1,4-diazabicyclo[2.2.2]octane (DABCO), are characterized by an increased detection sensitivity in electrospray ionization mass spectrometry (ESI-MS) and longer retention times on the reverse-phase (RP) chromatography columns. The improvement of the detection limit was observed even for peptides dissolved in 10 mM NaCl. Collision-induced dissociation tandem mass spectrometry of quaternary ammonium salts derivatives of peptides showed dominant a- and b-type ions, allowing facile sequencing of peptides. The bicyclic ionization tags are stable in collision-induced dissociation experiments, and the resulted fragmentation pattern is not significantly influenced by either acidic or basic amino acid residues in the peptide sequence. Obtained results indicate the general usefulness of the bicyclic quaternary ammonium ionization tags for ESI-MS/MS sequencing of peptides. Copyright © 2014 John Wiley & Sons, Ltd.

  17. Using fragmentation trees and mass spectral trees for identifying unknown compounds in metabolomics.

    Science.gov (United States)

    Vaniya, Arpana; Fiehn, Oliver

    2015-06-01

    Identification of unknown metabolites is the bottleneck in advancing metabolomics, leaving interpretation of metabolomics results ambiguous. The chemical diversity of metabolism is vast, making structure identification arduous and time consuming. Currently, comprehensive analysis of mass spectra in metabolomics is limited to library matching, but tandem mass spectral libraries are small compared to the large number of compounds found in the biosphere, including xenobiotics. Resolving this bottleneck requires richer data acquisition and better computational tools. Multi-stage mass spectrometry (MSn) trees show promise to aid in this regard. Fragmentation trees explore the fragmentation process, generate fragmentation rules and aid in sub-structure identification, while mass spectral trees delineate the dependencies in multi-stage MS of collision-induced dissociations. This review covers advancements over the past 10 years as a tool for metabolite identification, including algorithms, software and databases used to build and to implement fragmentation trees and mass spectral annotations.

  18. Toward a suitable structural analysis of gene delivery carrier based on polycationic carbohydrates by electron transfer dissociation tandem mass spectrometry

    International Nuclear Information System (INIS)

    Przybylski, Cédric; Benito, Juan M.; Bonnet, Véronique; Mellet, Carmen Ortiz; García Fernández, José M.

    2016-01-01

    Polycationic carbohydrates represent an attractive class of biomolecules for several applications and particularly as non viral gene delivery vectors. In this case, the establishment of structure-biological activity relationship requires sensitive and accurate characterization tools to both control and achieve fine structural deciphering. Electrospray-tandem mass spectrometry (ESI-MS/MS) appears as a suitable approach to address these questions. In the study herein, we have investigated the usefulness of electron transfer dissociation (ETD) to get structural data about five polycationic carbohydrates demonstrated as promising gene delivery agents. A particular attention was paid to determine the influence of charge states as well as both fluoranthene reaction time and supplementary activation (SA) on production of charge reduced species, fragmentation yield, varying from 2 to 62%, as well as to obtain the most higher both diversity and intensity of fragments, according to charge states and targeted compounds. ETD fragmentation appeared to be mainly directed toward pending group rather than carbohydrate cyclic scaffold leading to a partial sequencing for building blocks when amino groups are close to carbohydrate core, but allowing to complete structural deciphering of some of them, such as those including dithioureidocysteaminyl group which was not possible with CID only. Such findings clearly highlight the potential to help the rational choice of the suitable analytical conditions, according to the nature of the gene delivery molecules exhibiting polycationic features. Moreover, our ETD-MS/MS approach open the way to a fine sequencing/identification of grafted groups carried on various sets of oligo-/polysaccharides in various fields such as glycobiology or nanomaterials, even with unknown or questionable extraction, synthesis or modification steps. - Highlights: • The first ETD-MS/MS characterization of polycationic carbohydrate based non-viral gene delivery

  19. Toward a suitable structural analysis of gene delivery carrier based on polycationic carbohydrates by electron transfer dissociation tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Przybylski, Cédric, E-mail: cedric.przybylski@upmc.fr [Université d’Evry-Val-d’Essonne, Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, CNRS UMR 8587, Bâtiment Maupertuis, Bld F. Mitterrand, F-91025 Evry (France); Benito, Juan M. [Instituto de Investigaciones Químicas (IIQ), CSIC−Universidad de Sevilla, Américo Vespucio 49, Isla de la Cartuja, E-41092 Sevilla (Spain); Bonnet, Véronique [Université de Picardie Jules Verne, Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources, CNRS UMR 7378, 80039 Amiens (France); Mellet, Carmen Ortiz [Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, E-41012 Sevilla (Spain); García Fernández, José M. [Instituto de Investigaciones Químicas (IIQ), CSIC−Universidad de Sevilla, Américo Vespucio 49, Isla de la Cartuja, E-41092 Sevilla (Spain)

    2016-12-15

    Polycationic carbohydrates represent an attractive class of biomolecules for several applications and particularly as non viral gene delivery vectors. In this case, the establishment of structure-biological activity relationship requires sensitive and accurate characterization tools to both control and achieve fine structural deciphering. Electrospray-tandem mass spectrometry (ESI-MS/MS) appears as a suitable approach to address these questions. In the study herein, we have investigated the usefulness of electron transfer dissociation (ETD) to get structural data about five polycationic carbohydrates demonstrated as promising gene delivery agents. A particular attention was paid to determine the influence of charge states as well as both fluoranthene reaction time and supplementary activation (SA) on production of charge reduced species, fragmentation yield, varying from 2 to 62%, as well as to obtain the most higher both diversity and intensity of fragments, according to charge states and targeted compounds. ETD fragmentation appeared to be mainly directed toward pending group rather than carbohydrate cyclic scaffold leading to a partial sequencing for building blocks when amino groups are close to carbohydrate core, but allowing to complete structural deciphering of some of them, such as those including dithioureidocysteaminyl group which was not possible with CID only. Such findings clearly highlight the potential to help the rational choice of the suitable analytical conditions, according to the nature of the gene delivery molecules exhibiting polycationic features. Moreover, our ETD-MS/MS approach open the way to a fine sequencing/identification of grafted groups carried on various sets of oligo-/polysaccharides in various fields such as glycobiology or nanomaterials, even with unknown or questionable extraction, synthesis or modification steps. - Highlights: • The first ETD-MS/MS characterization of polycationic carbohydrate based non-viral gene delivery

  20. Collision-induced absorption intensity redistribution and the atomic pair polarizabilities

    International Nuclear Information System (INIS)

    Bulanin, M. O.

    1997-01-01

    A modified relation between the trace polarizability of a diatom and the S(-2) dipole sum is proposed that accounts for the effect of atomic collisions on the dipole oscillator strength distribution. Contribution to the collision-induced trace due to redistribution in the ionization continuum of Ar is evaluated and is found to be significant

  1. Protonation Sites, Tandem Mass Spectrometry and Computational Calculations of o-Carbonyl Carbazolequinone Derivatives.

    Science.gov (United States)

    Martínez-Cifuentes, Maximiliano; Clavijo-Allancan, Graciela; Zuñiga-Hormazabal, Pamela; Aranda, Braulio; Barriga, Andrés; Weiss-López, Boris; Araya-Maturana, Ramiro

    2016-07-05

    A series of a new type of tetracyclic carbazolequinones incorporating a carbonyl group at the ortho position relative to the quinone moiety was synthesized and analyzed by tandem electrospray ionization mass spectrometry (ESI/MS-MS), using Collision-Induced Dissociation (CID) to dissociate the protonated species. Theoretical parameters such as molecular electrostatic potential (MEP), local Fukui functions and local Parr function for electrophilic attack as well as proton affinity (PA) and gas phase basicity (GB), were used to explain the preferred protonation sites. Transition states of some main fragmentation routes were obtained and the energies calculated at density functional theory (DFT) B3LYP level were compared with the obtained by ab initio quadratic configuration interaction with single and double excitation (QCISD). The results are in accordance with the observed distribution of ions. The nature of the substituents in the aromatic ring has a notable impact on the fragmentation routes of the molecules.

  2. Structural characterisation of degradation products formed upon di-n-butyl phthalate radiolysis by high-performance liquid chromatography electro-spray tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tintaru, A.; Charles, L. [Univ Aix Marseille 1, CNRS, Lab Chim Provence Spectrometries Appl Chim Struct, UMR 6264, F-13397 Marseille (France); Univ Aix Marseille 2, CNRS, Lab Chim Provence Spectrometries Appl Chim Struct, UMR 6264, F-13397 Marseille (France); Labed, V. [CEA Marcoule, DTCD SPDE L2ED, F-30207 Bagnols Sur Ceze (France)

    2010-07-01

    Complete text of publication follows: Structural characterisation of 15 degradation products, formed upon di-n-butyl phthalate (DBP) radiolysis, has been achieved using a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) coupling. The dissociation behaviour of protonated DBP was first established to be further used to characterise structural deviation in the degradation products. Based on accurate mass measurements, compounds shown by HPLC-MS analysis were all found to be DBP oxidation products, amongst which various sets of isomers could be distinguished. Collision-induced dissociation experiments performed on each electro-sprayed molecule first allowed unambiguous definition of the location of the additional oxygen atoms; that is, in the alkyl branch or on the aromatic ring. Although location of the oxygen atom in the alkyl branches could not always be precisely determined, relative abundances of some product ions allowed oxygenated functions to be identified

  3. Mass spectral determination of enthalpies of dissociation of complex gaseous fluorides into neutral and charged particles. Pt. 4

    International Nuclear Information System (INIS)

    Sidorov, L.N.

    1981-01-01

    The dissociation fo alkali-metal compounds has been considered under the conditions of an isolated system and an actual effusion experiment, with due regard for the drawout field and the negative-ion flow. In both cases the work function if the inner surface of cell and the partial pressures of the charged and neutral products of dissociation have been calculated. The results obtained agree in those cases where the pressure of the neutral products of dissociation is much higher than the pressure of the ions, and the effect of the draw-out field and the ion flow can be ignored. In the most simple case, of the alkali-metal halides, the work function equals the half-sum of the ionization potential of the alkali metal and the electron affinity of the halogen. When the ion pressure is greater than that of the neutral products of dissocication, it is possible to regulate the pressure of alkali metal in the effusion chamber and its work function by varying the electric field and drawing out negative ions. In our experiments we succeeded in lowering the work function by more than an electronvolt and in obtaining measurable negative-ion flows at 600-700 K. The calculated and experimental results for KF, CsI and the systems KF-UF 4 and NaF-AlF 3 are compared. (orig.)

  4. Duality in diffraction dissociations

    International Nuclear Information System (INIS)

    Santoro, Alberto.

    1977-01-01

    Diffractive dissociations (aN→a*πN) are naturally explained and a model that accounts for the three-variable correlation (mass-transfer-Jackson angle correlation) is presented. This model takes into account the three possible exchanges: t (pion), u(a*) and s(a) channel exchanger. The physical consequences of the model are: a strong mass-slope correlation due to the zeros of the amplitude, a factorization of diffractive dissociations (factorization of the Pomeron), the possibility of extending this model to double diffractive dissociation and diffraction by nuclei. This model was applied to the NN→NπN reaction. Using the usual parameters of the Deck model, a comparison is made with experiments for all available distributions. the strong slope of the peak at 1400 MeV is naturally explained [fr

  5. Tandem mass spectrometry of nitric oxide and hydrogen sulfide releasing aspirins: a hint into activity behavior.

    Science.gov (United States)

    Crestoni, Maria Elisa; Chiavarino, Barbara; Guglielmo, Stefano; Lilla, Valentina; Fornarini, Simonetta

    2013-01-01

    Aspirin (acetylsalicylic acid, ASA) is the most popular non-steroidal anti-inflammatory drug. However, due to its action on cyclooxygenase and its acid nature, aspirin is associated with adverse gastrointestinal effects. In an effort to minimize these side effects, NO-donor and H2S-donor ASA co-drugs have been designed and tested. Their mass spectrometric behavior is now analyzed and reported. Positive ions were obtained by electrospray ionization involving protonation or alkali metal attachment. Their dissociation processes have been studied by collision induced dissociation in a triple quadrupole instrument. High mass accuracy measurements have been recorded on a Fourier transform ion cyclotron resonance mass spectrometer. The protonated molecules dissociate by an exclusive or largely prevailing path leading to acetyloxy-substituted benzoyl cation, namely an ASA unit. The process is reminiscent of the enzymatic hydrolysis, releasing intact ASA to a large extent. Only at higher collision energy does the formal ketene loss disrupt the ASA moiety. The gas phase chemistry of protonated ASA-releasing drugs develops along elementary dissociation steps analogous to the reactive processes in complex biological environments. This notion may provide a tool for preliminary testing of new compounds.

  6. Transition probability of the 5971-A line in neutral uranium from collision-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gagne, J.M.; Mongeau, B.; Demers, Y.; Pianarosa, P.

    1981-01-01

    From collision-induced fluorescence spectroscopy measurements, we have determined the transition probability Aof the 5971-A transition in neutral uranium. Our value, A 5971 = (5.9 +- 1.8) x 10 5 sec -1 , is, within experimental error, in good agreement with the previous determination of Corliss, A 5971 = (7.3 +- 3.0) x 10 5 sec -1 [J. Res. Nat. Bur. Stand. Sect. A 80,1 (1976)

  7. Diffractive dissociation in pp→Δ++π-p 1. Slope-mass-cos theta sup(G.J.) correlation

    International Nuclear Information System (INIS)

    Antunes, A.C.B.; Santoro, A.F.S.; Souza, M.H.G.

    1983-01-01

    The complete calculation for pp→Δ ++ π - p diffractive dissociation reaction at high energy in the frameworks of the Three Components Deck Model is made. This calculation suffers from some difficulties originated by the (3/2 + , 3/2 + , 1 - ) vertex that appears in one of the components. The main technical details are given and so this paper remains essentially technical. The conclusion, based on the results obtained is that the structures of 'zeros' or dips predicted by the Model can not be analytically seen because of the complexity of the formulae involved. But numerical calculations for several distributions are performed. A strong interference among the three components may appear according to a particular choice of the parameters. (Author) [pt

  8. Correlations in the hadronic double diffractive dissociation

    International Nuclear Information System (INIS)

    Goldegol, Alexandre.

    1991-05-01

    A given reaction of double diffractive dissociation is studied based on the three-component Deck Model. The correlations among the diffractive slope, the effective mass of the dissociated particle sub-system and the dissociation angle in the Gottfried-Jackson are studied based in this model. 9 refs, 19 figs

  9. Electron transfer dissociation of synthetic and natural peptides containing lanthionine/methyllanthionine bridges.

    Science.gov (United States)

    Dolle, Ashwini B; Jagadeesh, Narasimhappagari; Bhaumik, Suman; Prakash, Sunita; Biswal, Himansu S; Gowd, Konkallu Hanumae

    2018-06-15

    The modes of cleavage of lanthionine/methyllanthionine bridges under electron transfer dissociation (ETD) were investigated using synthetic and natural lantipeptides. Knowledge of the mass spectrometric fragmentation of lanthionine/methyllanthionine bridges may assist in the development of analytical methods for the rapid discovery of new lantibiotics. The present study strengthens the advantage of ETD in the characterization of posttranslational modifications of peptides and proteins. Synthetic and natural lantipeptides were obtained by desulfurization of peptide disulfides and cyanogen bromide digestion of the lantibiotic nisin, respectively. These peptides were subjected to electrospray ionization collision-induced dissociation tandem mass spectrometry (CID-MS/MS) and ETD-MS/MS using an HCT ultra ETDII ion trap mass spectrometer. MS 3 CID was performed on the desired product ions to prove cleavage of the lanthionine/methyllanthionine bridge during ETD-MS/MS. ETD has advantages over CID in the cleavage of the side chain of lanthionine/methyllanthionine bridges. The cleavage of the N-Cα backbone peptide bond followed by C-terminal side chain of the lanthionine bridge results in formation of c •+ and z + ions. Cleavage at the preceding peptide bond to the C-terminal side chain of lanthionine/methyllanthionine bridges yields specific fragments with the cysteine/methylcysteine thiyl radical and dehydroalanine. ETD successfully cleaves the lanthionine/methyllanthionine bridges of synthetic and natural lantipeptides. Diagnostic fragment ions of ETD cleavage of lanthionine/methyllanthionine bridges are the N-terminal cysteine/methylcysteine thiyl radical and C-terminal dehydroalanine. Detection of the cysteine/methylcysteine thiyl radical and dehydroalanine in combined ETD-CID-MS may be used for the rapid identification of lantipeptide natural products. Copyright © 2018 John Wiley & Sons, Ltd.

  10. Surface Induced Dissociation Coupled with High Resolution Mass Spectrometry Unveils Heterogeneity of a 211 kDa Multicopper Oxidase Protein Complex

    Science.gov (United States)

    Zhou, Mowei; Yan, Jing; Romano, Christine A.; Tebo, Bradley M.; Wysocki, Vicki H.; Paša-Tolić, Ljiljana

    2018-01-01

    Manganese oxidation is an important biogeochemical process that is largely regulated by bacteria through enzymatic reactions. However, the detailed mechanism is poorly understood due to challenges in isolating and characterizing these unknown enzymes. A manganese oxidase, Mnx, from Bacillus sp. PL-12 has been successfully overexpressed in active form as a protein complex with a molecular mass of 211 kDa. We have recently used surface induced dissociation (SID) and ion mobility-mass spectrometry (IM-MS) to release and detect folded subcomplexes for determining subunit connectivity and quaternary structure. The data from the native mass spectrometry experiments led to a plausible structural model of this multicopper oxidase, which has been difficult to study by conventional structural biology methods. It was also revealed that each Mnx subunit binds a variable number of copper ions. Becasue of the heterogeneity of the protein and limited mass resolution, ambiguities in assigning some of the observed peaks remained as a barrier to fully understanding the role of metals and potential unknown ligands in Mnx. In this study, we performed SID in a modified Fourier transform-ion cyclotron resonance (FTICR) mass spectrometer. The high mass accuracy and resolution offered by FTICR unveiled unexpected artificial modifications on the protein that had been previously thought to be iron bound species based on lower resolution spectra. Additionally, isotopically resolved spectra of the released subcomplexes revealed the metal binding stoichiometry at different structural levels. This method holds great potential for in-depth characterization of metalloproteins and protein-ligand complexes. [Figure not available: see fulltext.

  11. Regiospecific analysis of neutral ether lipids by liquid chromatography/electrospray ionization/single quadrupole mass spectrometry: validation with synthetic compounds

    DEFF Research Database (Denmark)

    Hartvigsen, Karsten; Ravandi, A.; Bukhave, Klaus

    2001-01-01

    A reversed-phase high-performance liquid chromatography (HPLC) method with on-line electrospray ionization/collision-induced dissociation/mass spectrometry (ESI/CID/MS) is presented for the regiospecific analysis of synthetic reference compounds of neutral ether lipids. The reference compounds were...... characterized by chromatographic retention times, full mass spectra, and fragmentation patterns as an aid to clarify the regiospecificity of ether lipids from natural sources. The results clearly show that single quadrupole mass spectroscopic analysis may elucidate the regiospecific structure of neutral ether...... + H - H2O](+), whereas the reverse situation characterized the sn-3 species. Furthermore, corresponding sn-2 and sn-3 species were separated by the chromatographic system. However, loss of water was promoted as fatty acid unsaturation was raised, which may complicate interpretation of the mass spectra...

  12. Front-End Electron Transfer Dissociation Coupled to a 21 Tesla FT-ICR Mass Spectrometer for Intact Protein Sequence Analysis

    Science.gov (United States)

    Weisbrod, Chad R.; Kaiser, Nathan K.; Syka, John E. P.; Early, Lee; Mullen, Christopher; Dunyach, Jean-Jacques; English, A. Michelle; Anderson, Lissa C.; Blakney, Greg T.; Shabanowitz, Jeffrey; Hendrickson, Christopher L.; Marshall, Alan G.; Hunt, Donald F.

    2017-09-01

    High resolution mass spectrometry is a key technology for in-depth protein characterization. High-field Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) enables high-level interrogation of intact proteins in the most detail to date. However, an appropriate complement of fragmentation technologies must be paired with FTMS to provide comprehensive sequence coverage, as well as characterization of sequence variants, and post-translational modifications. Here we describe the integration of front-end electron transfer dissociation (FETD) with a custom-built 21 tesla FT-ICR mass spectrometer, which yields unprecedented sequence coverage for proteins ranging from 2.8 to 29 kDa, without the need for extensive spectral averaging (e.g., 60% sequence coverage for apo-myoglobin with four averaged acquisitions). The system is equipped with a multipole storage device separate from the ETD reaction device, which allows accumulation of multiple ETD fragment ion fills. Consequently, an optimally large product ion population is accumulated prior to transfer to the ICR cell for mass analysis, which improves mass spectral signal-to-noise ratio, dynamic range, and scan rate. We find a linear relationship between protein molecular weight and minimum number of ETD reaction fills to achieve optimum sequence coverage, thereby enabling more efficient use of instrument data acquisition time. Finally, real-time scaling of the number of ETD reactions fills during method-based acquisition is shown, and the implications for LC-MS/MS top-down analysis are discussed. [Figure not available: see fulltext.

  13. A panorama of phase transition signals and influence of collision-induced correlations

    Energy Technology Data Exchange (ETDEWEB)

    Bougault, R. [LPC Caen IN2P3-CNRS/ENSICAEN et Univ., 14 - Caen (France)

    2003-07-01

    The presented results will show the richness of nuclear heavy-ion physics where data are accumulated as a succession of independent events. The different reaction mechanisms can provide for 39 A.MeV Ta+Au, 40 and 80 A.MeV Au+Au peripheral collisions a set of data almost free of entrance channel effects as well as a set of events where collision-induced correlations can be evidenced. The event selection method will be presented and it will be shown how the entrance channel dynamical effects affect determination of heat capacity through partial energy fluctuation measurements. (author)

  14. A panorama of phase transition signals and influence of collision-induced correlations

    International Nuclear Information System (INIS)

    Bougault, R.

    2003-01-01

    The presented results will show the richness of nuclear heavy-ion physics where data are accumulated as a succession of independent events. The different reaction mechanisms can provide for 39 A.MeV Ta+Au, 40 and 80 A.MeV Au+Au peripheral collisions a set of data almost free of entrance channel effects as well as a set of events where collision-induced correlations can be evidenced. The event selection method will be presented and it will be shown how the entrance channel dynamical effects affect determination of heat capacity through partial energy fluctuation measurements. (author)

  15. Collision-induced stimulated photon echoes in ‘strong’ magnetic field

    Science.gov (United States)

    Reshetov, V. A.

    2018-05-01

    Collision-induced stimulated photon echoes formed in a gaseous medium on the transition with the angular momentum change Ja=0 → Jb=1 under the action of ‘strong’ longitudinal magnetic field, when the echo pulse becomes unpolarized, are considered with an account of elastic depolarizing collisions. In the case of narrow spectral line the explicit expressions for the echo polarization density matrix and the degree of polarization are obtained. In the case of broad spectral line the results of the numeric calculations reproduce qualitatively the curve obtained in the experiments with ytterbium vapor.

  16. The application of "double isolation" in Fourier transform ion cyclotron resonance sustained off-resonance irradiation collisionally-induced dissociation tandem mass spectrometry to remove labile isobaric impurities.

    Science.gov (United States)

    Gates, Paul J; Lopes, Norberto P; Pinto, Emani; Colepicolo, Pio; Cardozo, Karina H M

    2011-01-01

    This study reports the application of "double isolation" in sustained off-resonance irradiation collisionally-induced dissociation tandem mass spectrometry (SORI-CID-MS/MS) to remove radio- frequency (RF) fragment ions of very close mass isobaric ions (0.02 m/z apart). Analyses were performed with a fraction of a biological extract isolated from a macroalgae containing the mycosporine-like amino acid asterina-330. Direct isolation of the precursor ion by narrowing the isolation window proved ineffective as it impinged upon the required ion thus substantially reducing its intensity. By increasing the correlated sweep time, ejection efficiency of the isolation was improved, but caused the unwanted side-effect of RF fragmentation of labile ions. Finally, by skipping the ion activation step and performing a second isolation (in the MS(3) module) the RF fragments from the first isolation were removed leaving a very pure isolation of the required precursor ion and allowed a very clean CID fragmentation. We demonstrated that the m/z 272.1351 ion is derived from the loss of NH(3) from m/z 289.1620 isobaric impurity and is not related to asterina-330. This application represents a powerful tool to remove unwanted ions in the MS/MS spectrum that result from fragmentation of isobaric ions.

  17. Collision-Induced Infrared Absorption by Hydrogen-Helium gas mixtures at Thousands of Kelvin

    Science.gov (United States)

    Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

    2010-10-01

    The interaction-induced absorption by collisional pairs of H2 molecules is an important opacity source in the atmospheres of the outer planets and cool stars ^[1]. The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H2--H2, H2--He, and H2--H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin ^[2]. Laboratory measurements of interaction-induced absorption spectra by H2 pairs exist only at room temperature and below. We show that our results reproduce these measurements closely ^[2], so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures ^[2]. [1] L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 [2] Xiaoping Li, Katharine L. C. Hunt, Fei Wang, Martin Abel, and Lothar Frommhold, ``Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin'', International Journal of Spectroscopy, vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201

  18. Triple Quadrupole Versus High Resolution Quadrupole-Time-of-Flight Mass Spectrometry for Quantitative LC-MS/MS Analysis of 25-Hydroxyvitamin D in Human Serum

    Science.gov (United States)

    Geib, Timon; Sleno, Lekha; Hall, Rabea A.; Stokes, Caroline S.; Volmer, Dietrich A.

    2016-08-01

    We describe a systematic comparison of high and low resolution LC-MS/MS assays for quantification of 25-hydroxyvitamin D3 in human serum. Identical sample preparation, chromatography separations, electrospray ionization sources, precursor ion selection, and ion activation were used; the two assays differed only in the implemented final mass analyzer stage; viz. high resolution quadrupole-quadrupole-time-of-flight (QqTOF) versus low resolution triple quadrupole instruments. The results were assessed against measured concentration levels from a routine clinical chemiluminescence immunoassay. Isobaric interferences prevented the simple use of TOF-MS spectra for extraction of accurate masses and necessitated the application of collision-induced dissociation on the QqTOF platform. The two mass spectrometry assays provided very similar analytical figures of merit, reflecting the lack of relevant isobaric interferences in the MS/MS domain, and were successfully applied to determine the levels of 25-hydroxyvitamin D for patients with chronic liver disease.

  19. Collision-induced absorption with exchange effects and anisotropic interactions: theory and application to H2 - H2.

    Science.gov (United States)

    Karman, Tijs; van der Avoird, Ad; Groenenboom, Gerrit C

    2015-02-28

    We discuss three quantum mechanical formalisms for calculating collision-induced absorption spectra. First, we revisit the established theory of collision-induced absorption, assuming distinguishable molecules which interact isotropically. Then, the theory is rederived incorporating exchange effects between indistinguishable molecules. It is shown that the spectrum can no longer be written as an incoherent sum of the contributions of the different spherical components of the dipole moment. Finally, we derive an efficient method to include the effects of anisotropic interactions in the computation of the absorption spectrum. This method calculates the dipole coupling on-the-fly, which allows for the uncoupled treatment of the initial and final states without the explicit reconstruction of the many-component wave functions. The three formalisms are applied to the collision-induced rotation-translation spectra of hydrogen molecules in the far-infrared. Good agreement with experimental data is obtained. Significant effects of anisotropic interactions are observed in the far wing.

  20. Mass spectrometry of selective androgen receptor modulators.

    Science.gov (United States)

    Thevis, Mario; Schänzer, Wilhelm

    2008-07-01

    Nonsteroidal selective androgen receptor modulators (SARMs) are an emerging class of drugs for treatment of various diseases including osteoporosis and muscle wasting as well as the correction of age-related functional decline such as muscle strength and power. Several SARMs, which have advanced to preclinical and clinical trials, are composed of diverse chemical structures including arylpropionamide-, bicyclic hydantoin-, quinoline-, and tetrahydroquinoline-derived nuclei. Since January 2008, SARMs have been categorized as anabolic agents and prohibited by the World Anti-Doping Agency (WADA). Suitable detection methods for these low-molecular weight drugs were based on mass spectrometric approaches, which necessitated the elucidation of dissociation pathways in order to characterize and identify the target analytes in doping control samples as well as potential metabolic products and synthetic analogs. Fragmentation patterns of representatives of each category of SARMs after electrospray ionization (ESI) and collision-induced dissociation (CID) as well as electron ionization (EI) are summarized. The complexity and structural heterogeneity of these drugs is a daunting challenge for detection methods. Copyright 2008 John Wiley & Sons, Ltd.

  1. A fragmentation study of kaempferol using electrospray quadrupole time-of-flight mass spectrometry at high mass resolution

    Science.gov (United States)

    March, Raymond E.; Miao, Xiu-Sheng

    2004-02-01

    A mass spectrometric method based on the combined use of electrospray ionization, collision-induced dissociation and tandem mass spectrometry at high mass resolution has been applied to an investigation of the structural characterization of protonated and deprotonated kaempferol (3,5,7,4'-tetrahydroxyflavone). Low-energy product ion mass spectra of [M+H]+ ions showed simple fragmentations of the C ring that permitted characterization of the substituents in the A and B rings. In addition, four rearrangement reactions accompanied by losses of C2H2O, CHO[radical sign], CO, and H2O were observed. Low-energy product ion mass spectra of [M-H]- ions showed only four rearrangement reactions accompanied by losses of OH[radical sign], CO, CH2O, and C2H2O. The use of elevated cone voltages permitted observation of product ion mass spectra of selected primary and secondary fragment ions so that each fragment ion reported was observed as a direct product of its immediate precursor ion. Product ion mass spectra examined at high mass resolution allowed unambiguous determination of the elemental composition of fragment ions and resolution of two pairs of isobars. Fragmentation mechanisms and ion structures have been proposed.

  2. Fragmentation analysis of water-soluble atmospheric organic matter using ultrahigh-resolution FT-ICR mass spectrometry.

    Science.gov (United States)

    Leclair, Jeffrey P; Collett, Jeffrey L; Mazzoleni, Lynn R

    2012-04-17

    Isolated water-soluble atmospheric organic matter (AOM) analytes extracted from radiation fogwater samples were analyzed using collision induced dissociation with ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Tandem mass analysis was performed on several mass ranges between 100 and 400 Da to characterize the functional groups of AOM species. Compounds containing nitrogen and/or sulfur were targeted because of the high number of oxygen atoms contained in their molecular formulas. Due to the large number of isobaric ions in the precursor isolation ranges, large numbers of product ions resulted from collision induced dissociation. Common neutral losses were assigned by matching the molecular formulas of the expected product ions with the detected product ions within the appropriate mass spectra. Since polar functional groups are expected to affect the hygroscopic properties of aerosols, the losses of H(2)O, CO(2), CH(3)OH, HNO(3), CH(3)NO(3), SO(3), SO(4) and combinations of these were specifically targeted. Among the 421 compounds studied, the most frequently observed neutral losses were CO(2) (54%), H(2)O (43%) and CH(3)OH (40%). HNO(3) losses were observed for 63% of the studied nitrogen containing compounds and 33% of the studied compounds containing both nitrogen and sulfur. SO(3) losses were observed for 85% of the studied sulfur containing compounds and 42% of studied compounds containing both nitrogen and sulfur. A number of molecular formulas matching those of monoterpene ozonolysis SOA were observed; they include organonitrates, organosulfates, and nitroxy-organosulfates. Overall, the results of fragmentation analysis of 400+ individual molecular precursors elucidate the complexity and multifunctional nature of the isolated water-soluble AOM.

  3. Inductively coupled plasma mass spectrometry with hexapole collision cell: figures of merit and applications

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, S.F. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen]|[Radiation Physics and Chemistry Problems Inst., Minsk (Belarus); Becker, J.S. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen

    2000-11-01

    The use of gas-filled multipole collision cells represents important progress in ICP-MS instrumentation. It enables an increase in element sensitivity based on the improvement of ion transmission efficiency from near thermalization and collisional focusing of ions. In addition, gas-phase ion-molecule chemistry can be applied in order to reduce mass spectral interferences via charge transfer reaction of interfering ions with reaction gas or via fragmentation of interfering molecular ions by collision-induced dissociation. The application of a hexapole collision cell in quadrupole based ICP-MS (HEX-ICP-QMS) was studied systematically in order to characterize the analytical figures of merit of this approach. Additionally, the performance of different solution introduction systems as well as an inductively coupled plasma shielded torch was studied for use with HEX-ICP-QMS. (orig.)

  4. Sites involved in intra- and interdomain allostery associated with the activation of factor VIIa pinpointed by hydrogen-deuterium exchange and electron transfer dissociation mass spectrometry.

    Science.gov (United States)

    Song, Hongjian; Olsen, Ole H; Persson, Egon; Rand, Kasper D

    2014-12-19

    Factor VIIa (FVIIa) is a trypsin-like protease that plays an important role in initiating blood coagulation. Very limited structural information is available for the free, inactive form of FVIIa that circulates in the blood prior to vascular injury and the molecular details of its activity enhancement remain elusive. Here we have applied hydrogen/deuterium exchange mass spectrometry coupled to electron transfer dissociation to pinpoint individual residues in the heavy chain of FVIIa whose conformation and/or local interaction pattern changes when the enzyme transitions to the active form, as induced either by its cofactor tissue factor or a covalent active site inhibitor. Identified regulatory residues are situated at key sites across one continuous surface of the protease domain spanning the TF-binding helix across the activation pocket to the calcium binding site and are embedded in elements of secondary structure and at the base of flexible loops. Thus these residues are optimally positioned to mediate crosstalk between functional sites in FVIIa, particularly the cofactor binding site and the active site. Our results unambiguously show that the conformational allosteric activation signal extends to the EGF1 domain in the light chain of FVIIa, underscoring a remarkable intra- and interdomain allosteric regulation of this trypsin-like protease. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Determination of triacylglycerol regioisomers using electrospray ionization-quadrupole ion trap mass spectrometry with a kinetic method.

    Science.gov (United States)

    Leveque, Nathalie L; Acheampong, Akwasi; Heron, Sylvie; Tchapla, Alain

    2012-04-13

    The kinetic method was applied to differentiate and quantify mixtures of regioisomeric triacylglycerols (TAGs) by generating and mass selecting alkali ion bound metal dimeric clusters with a TAG chosen as reference (ref) and examining their competitive dissociations in a quadrupole ion trap mass spectrometer. This methodology readily distinguished pairs of regioisomers (AAB/ABA) such as LLO/LOL, OOP/OPO and SSP/SPS and consequently distinguished sn-1/sn-3, sn-2 substituents on the glycerol backbone. The dimeric complex ions [ref, Li, TAG((AAB and/or ABA))](+) generated by electrospray ionization mass spectrometry were subjected to collision induced dissociation causing competitive loss of either the neutral TAG reference (ref) leading to [Li(AAB and/or ABA)](+) or the neutral TAG molecule (TAG((AAB and/or ABA))) leading to [ref, Li](+). The ratio of the two competitive dissociation rates, defined by the product ion branching ratio (R(iso)), was related via the kinetic method to the regioisomeric composition of the investigated TAG mixture. In this work, a linear correlation was established between composition of the mixture of each TAG regioisomer and the logarithm of the branching ratio for competitive fragmentation. Depending on the availability of at least one TAG regioisomer as standard, the kinetic method and the standard additions method led to the quantitative analysis of natural TAG mixtures. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Protein Analysis by Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Cindic, M.

    2008-04-01

    mass spectrometry (collision-induced dissociation, CID or post-source decay, PSD. Different types of fragments and main fragmentation paths are shown in Figs. 6 and 8. Fragmentation pathway of a doubly charged tryptic pentapeptide to b- and y-ions by collision-induced dissociation inside the mass spectrometer is described more in details in Fig. 7. All types of fragment ions are summarized in table 3. Since the any of the peptide bonds can be broken in several ways, the MS/MS spectra are complex, and quite difficult to interpret. Chemical derivatization is used to obtain only or predominantly one type of fragment ions. Sulfonation of N-terminal amino group enhance PSD sequencing, producing mainly y-type fragment ions. The mass difference of two consecutive y-ions corresponds to an amino acid mass, so the peptide sequence can be obtained with minimal or no assistance from genomic data, e. g. de novo protein sequencing is possible. Fig. 9 represents the strategy for the protein identification by mass spectrometry. Various chemical modifications on the peptide fragmentation patterns are shown in Fig. 10.

  7. Ozone-induced dissociation on a traveling wave high-resolution mass spectrometer for determination of double-bond position in lipids.

    Science.gov (United States)

    Vu, Ngoc; Brown, Jeffery; Giles, Kevin; Zhang, Qibin

    2017-09-15

    The position of C=C within fatty acyl chains affects the biological function of lipids. Ozone-induced dissociation mass spectrometry (OzID-MS) has great potential in determination of lipid double-bond position, but has generally been implemented on low-resolution ion trap mass spectrometers. In addition, most of the OzID-MS experiments carried out so far were focused on the sodiated adducts of lipids; fragmentation of the most commonly observed protonated ions generated in LC/MS-based lipidomics workflow has been less explored. Ozone generated in line from an ozone generator was connected to the trap and transfer gas supply line of a Synapt G2 high-resolution mass spectrometer. Protonated ions of different phosphatidylcholines (PC) were generated by electrospray ionization through direct infusion. Different parameters, including traveling wave height and velocity, trap entrance and DC potential, were adjusted to maximize the OzID efficiency. sn-positional isomers and cis/trans isomers of lipids were compared for their reactivity with ozone. Traveling wave height and velocity were tuned to prolong the encounter time between lipid ions and ozone, and resulted in improved OzID efficiency, as did increasing trapping region DC and entrance potential. Under optimized settings, at least 1000 times enhancement in OzID efficiency was achieved compared to that under default settings for monounsaturated PC standards. Monounsaturated C=C in the sn-2 PC isomer reacted faster with ozone than the sn-1 isomer. Similarly, the C=C in trans PC reacted faster than in cis PC. This is the first implementation of OzID in the trap and transfer region of a traveling wave enabled high-resolution mass spectrometer. The OzID reaction efficiency is significantly improved by slowing down ions in the trap region for their prolonged interaction with ozone. This will facilitate application of high-resolution OzID-MS in lipidomics. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Diffraction dissociation at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Jenkovszky, Laszlo [Bogolyubov Institute for Theoretical Physics (BITP), Ukrainian National Academy of Sciences 14-b, Metrolohichna str., Kiev, 03680, Ukraine and Wigner Research Centre for Physics, Hungarian Academy of Sciences 1525 Budapest, POB 49 (Hungary); Orava, Risto [Institute of Physics, Division of Elementary Particle Physics, P.O. Box 64 (Gustaf Haellstroeminkatu 2a), FI-00014 University of Helsinki, Finland and CERN, CH-1211 Geneva 23 (Switzerland); Salii, Andrii [Bogolyubov Institute for Theoretical Physics (BITP), Ukrainian National Academy of Sciences 14-b, Metrolohichna str., Kiev, 03680 (Ukraine)

    2013-04-15

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  9. Diffraction dissociation at the LHC

    International Nuclear Information System (INIS)

    Jenkovszky, László; Orava, Risto; Salii, Andrii

    2013-01-01

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  10. ESI-MS/MS Identification of a Bradykinin-Potentiating Peptide from Amazon Bothrops atrox Snake Venom Using a Hybrid Qq-oaTOF Mass Spectrometer

    Science.gov (United States)

    Coutinho-Neto, Antonio; Caldeira, Cleópatra A. S.; Souza, Gustavo H. M. F.; Zaqueo, Kayena D.; Kayano, Anderson M.; Silva, Rodrigo S.; Zuliani, Juliana P.; Soares, Andreimar M.; Stábeli, Rodrigo G.; Calderon, Leonardo A.

    2013-01-01

    A bradykinin-potentiating peptide (BPP) from Amazon Bothrops atrox venom with m/z 1384.7386 was identified and characterized by collision induced dissociation (CID) using an ESI-MS/MS spectra obtained in positive ion mode on a hybrid Qq-oaTOF mass spectrometer, Xevo G2 QTof MS (Waters, Manchester, UK). De novo peptide sequence analysis of the CID fragmentation spectra showed the amino acid sequence ZKWPRPGPEIPP, with a pyroglutamic acid and theoretical monoisotopic m/z 1384.7378, which is similar to experimental data, showing a mass accuracy of 0.6 ppm. The peptide is homologous to other BPP from Bothrops moojeni and was named as BPP-BAX12. PMID:23430539

  11. Electrospray ionization tandem mass spectrometry of ammonium cationized polyethers.

    Science.gov (United States)

    Nasioudis, Andreas; Heeren, Ron M A; van Doormalen, Irene; de Wijs-Rot, Nicolette; van den Brink, Oscar F

    2011-05-01

    Quaternary ammonium salts (Quats) and amines are known to facilitate the MS analysis of high molar mass polyethers by forming low charge state adduct ions. The formation, stability, and behavior upon collision-induced dissociation (CID) of adduct ions of polyethers with a variety of Quats and amines were studied by electrospray ionization quadrupole time-of-flight, quadrupole ion trap, and linear ion trap tandem mass spectrometry (MS/MS). The linear ion trap instrument was part of an Orbitrap hybrid mass spectrometer that allowed accurate mass MS/MS measurements. The Quats and amines studied were of different degree of substitution, structure, and size. The stability of the adduct ions was related to the structure of the cation, especially the amine's degree of substitution. CID of singly/doubly charged primary and tertiary ammonium cationized polymers resulted in the neutral loss of the amine followed by fragmentation of the protonated product ions. The latter reveals information about the monomer unit, polymer sequence, and endgroup structure. In addition, the detection of product ions retaining the ammonium ion was observed. The predominant process in the CID of singly charged quaternary ammonium cationized polymers was cation detachment, whereas their doubly charged adduct ions provided the same information as the primary and tertiary ammonium cationized adduct ions. This study shows the potential of specific amines as tools for the structural elucidation of high molar mass polyethers. © American Society for Mass Spectrometry, 2011

  12. Characterization of primaquine imidazolidin-4-ones with antimalarial activity by electrospray ionization-ion trap mass spectrometry

    Science.gov (United States)

    Vale, Nuno; Moreira, Rui; Gomes, Paula

    2008-02-01

    The extensive characterization by electrospray ionization-ion trap mass spectrometry (ESI-MSn) of 20 imidazolidin-4-ones derived from the antimalarial primaquine was well obtained. These compounds are being under investigation as potential antimalarials, as they have been previously found to be active against rodent P. berghei malaria and to be highly stable under physiological conditions. Experiments by collision-induced dissociation (CID) in the nozzle-skimmer region or by tandem-MS have shown the title compounds to be remarkably stable. Mechanisms are proposed to explain the major fragmentations observed in ESI-MSn experiments. Overall, this work represents an unprecedented contribution to a deeper insight into imidazolidin-4-one antimalarials based on a classic 8-aminoquinolinic scaffold. Data herein reported and discussed may be an useful guide for future studies on therapeutically relevant molecules possessing either the 8-aminoquinoline or the imidazolidin-4-one motifs.

  13. UV-induced bond modifications in thymine and thymine dideoxynucleotide: structural elucidation of isomers by differential mobility mass spectrometry.

    Science.gov (United States)

    St-Jacques, Antony; Anichina, Janna; Schneider, Bradley B; Covey, Thomas R; Bohme, Diethard K

    2010-07-15

    Differential mobility spectrometry has been applied to reveal the occurrence of isomerization of thymine nucleobase and of thymine dideoxynucleotide d(5'-TT-3') due to bond redisposition induced by UV irradiation at 254 nm of frozen aqueous solutions of these molecules. Collision-induced dissociation (CID) spectra of electrosprayed photoproducts of the thymine solution suggest the presence of two isomers (the so-called cyclobutane and 6,4-photoproducts) in addition to the proton-bound thymine dimer, and these were separated using differential mobility spectrometry/mass spectrometry (DMS/MS) techniques with water as the modifier. Similar experiments with d(5'-TT-3') revealed the formation of a new isomer of deprotonated thymine dideoxynucleotide upon UV irradiation that was easily distinguished using DMS/MS with isopropanol as the modifier. The results reinforce the usefulness of DMS/MS in isomer separation.

  14. Assessing the relative stabilities of engineered hemoglobins using electrospray mass spectrometry.

    Science.gov (United States)

    Apostol, I

    1999-07-15

    An ion trap mass spectrometer equipped with an electrospray source was used to examine the relative thermodynamic stabilities of various hemoglobins with respect to both tetramer dissociation and hemin dissociation. The results demonstrated that the stability of hemoglobin molecules can be differentiated by the amount of applied collision-induced dissociation (CID) energy necessary to break up the intact tetramer into its constituent globins. The stability of the intact tetramer was affected by single mutations in the beta-globins. The stabilities of the constituent hologlobins were assessed via trap CID of selected ions. The results demonstrated the importance of the contributions of the hologlobin components to the stability of the intact tetramer. Genetic fusion of two alpha-globins, through the introduction of a single glycine residue between the C-terminus of one alpha-chain and the N-terminus of the second, significantly increased the stability of the hemoglobin pseudo-tetramer. Chemical crosslinking of the beta-globins in addition to genetic fusion of alpha-globins further stabilized the hemoglobin molecule. A dihemoglobin molecule produced by the genetic fusion of two di-alpha-globins with a flexible linker demonstrated a decreased stability relative to the corresponding monohemoglobin. Copyright 1999 Academic Press.

  15. Hot filament-dissociation of (CH3)3SiH and (CH3)4Si, probed by vacuum ultra violet laser time of flight mass spectroscopy.

    Science.gov (United States)

    Sharma, Ramesh C; Koshi, Mitsuo

    2006-11-01

    The decomposition of trimethylsilane and tetramethylsilane has been investigated for the first time, using hot wire (catalytic) at various temperatures. Trimethylsilane is catalytic-dissociated in these species SiH(2), CH(3)SiH, CH(3), CH(2)Si. Time of flight mass spectroscopy signal of these species are linearly increasing with increasing catalytic-temperature. Time of flight mass spectroscopy (TOFMS) signals of (CH(3))(3)SiH and photodissociated into (CH(3))(2)SiH are decreasing with increasing hot filament temperature. TOFMS signal of (CH(3))(4)Si is decreasing with increasing hot wire temperature, but (CH(3))(3)Si signal is almost constant with increasing the temperature. We calculated activation energies of dissociated species of the parental molecules for fundamental information of reaction kinetics for the first time. Catalytic-dissociation of trimethylsilane, and tetramethylsilane single source time of flight coupled single photon VUV (118 nm) photoionization collisionless radicals at temperature range of tungsten filament 800-2360 K. The study is focused to understand the fundamental information on reaction kinetics of these molecules at hot wire temperature, and processes of catalytic-chemical vapour deposition (Cat-CVD) technique which could be implemented in amorphous and crystalline SiC semiconductors thin films.

  16. Matrix-assisted laser desorption/ionization time-of-flight and nano-electrospray ionization ion trap mass spectrometric characterization of 1-cyano-2-substituted-benz[f]isoindole derivatives of peptides for fluorescence detection

    DEFF Research Database (Denmark)

    Linnemayr, K; Brückner, A; Körner, R

    1999-01-01

    A series of hexa- to decapeptides (molecular mass range 800-1200) were labeled with naphthalene-2,3-dicarboxaldehyde, which preferentially reacts with the primary amino groups of a peptide. A highly stable peptide conjugate is formed, which allows selective analysis by fluorescence at excitation...... and emission wavelengths of 420 and 490 nm, respectively. After removal of unreacted compounds, the peptide conjugates were characterized by matrix-assisted laser desorption/ionization (MALDI) time-of-flight and nano-electrospray ionization (ESI) ion trap mass spectrometry. They readily form both [M + H]+ ions...... by MALDI and both [M + H]+ and [M + 2H]2+ ions by ESI. Furthermore, the fragmentation behavior of the N-terminally tagged peptides, exhibiting an uncharged N-terminus, was investigated applying post-source decay fragmentation with a curved field reflector and collision-induced dissociation...

  17. Collision-induced light scattering in a thin xenon layer between graphite slabs - MD study.

    Science.gov (United States)

    Dawid, A; Górny, K; Wojcieszyk, D; Dendzik, Z; Gburski, Z

    2014-08-14

    The collision-induced light scattering many-body correlation functions and their spectra in thin xenon layer located between two parallel graphite slabs have been investigated by molecular dynamics computer simulations. The results have been obtained at three different distances (densities) between graphite slabs. Our simulations show the increased intensity of the interaction-induced light scattering spectra at low frequencies for xenon atoms in confined space, in comparison to the bulk xenon sample. Moreover, we show substantial dependence of the interaction-induced light scattering correlation functions of xenon on the distances between graphite slabs. The dynamics of xenon atoms in a confined space was also investigated by calculating the mean square displacement functions and related diffusion coefficients. The structural property of confined xenon layer was studied by calculating the density profile, perpendicular to the graphite slabs. Building of a fluid phase of xenon in the innermost part of the slot was observed. The nonlinear dependence of xenon diffusion coefficient on the separation distance between graphite slabs has been found. Copyright © 2014. Published by Elsevier B.V.

  18. Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin

    Directory of Open Access Journals (Sweden)

    Xiaoping Li

    2010-01-01

    Full Text Available Collision-induced absorption by hydrogen and helium in the stellar atmospheres of cool white dwarfs causes the emission spectra to differ significantly from the expected blackbody spectra of the cores. For detailed modeling of radiative processes at temperatures up to 7000 K, the existing H2–H2 induced dipole and potential energy surfaces of high quality must be supplemented by calculations with the H2 bonds stretched or compressed far from the equilibrium length. In this work, we describe new dipole and energy surfaces, based on more than 20 000 ab initio calculations for H2–H2. Our results agree well with previous ab initio work (where those data exist; the calculated rototranslational absorption spectrum at 297.5 K matches experiment similarly well. We further report the calculated absorption spectra of H2–H2 for frequencies from the far infrared to 20 000 cm−1, at temperatures of 600 K, 1000 K, and 2000 K, for which there are no experimental data.

  19. High-energy limit of collision-induced false vacuum decay

    Energy Technology Data Exchange (ETDEWEB)

    Demidov, Sergei; Levkov, Dmitry [Institute for Nuclear Research of the Russian Academy of Sciences,60-th October Anniversary Prospect 7a, Moscow, 117312 (Russian Federation)

    2015-06-17

    We develop a consistent semiclassical description of field-theoretic collision-induced tunneling at arbitrary high collision energies. As a playground we consider a (1+1)-dimensional false vacuum decay initiated by a collision of N particles at energy E, paying special attention to the realistic case of N=2 particles. We demonstrate that the cross section of this process is exponentially suppressed at all energies. Moreover, the respective suppressesion exponent F{sub N}(E) exhibits a specific behavior which is significant for our semiclassical method and assumed to be general: it decreases with energy, reaches absolute minimum F=F{sub min}(N) at a certain threshold energy E=E{sub rt}(N), and stays constant at higher energies. We show that the minimal suppression F{sub min}(N) and threshold energy can be evaluated using a special class of semiclassical solutions which describe exponentially suppressed transitions but nevertheless evolve in real time. Importantly, we argue that the cross section at energies above E{sub rt}(N) is computed perturbatively in the background of the latter solutions, and the terms of this perturbative expansion stay bounded in the infinite-energy limit. Transitions in the high-energy regime proceed via emission of many soft quanta with total energy E{sub rt}; the energy excess E−E{sub rt} remains in the colliding particles till the end of the process.

  20. Hydrogen/deuterium exchange mass spectrometry with top-down electron capture dissociation for characterizing structural transitions of a 17 kDa protein.

    Science.gov (United States)

    Pan, Jingxi; Han, Jun; Borchers, Christoph H; Konermann, Lars

    2009-09-09

    Amide H/D exchange (HDX) mass spectrometry (MS) is widely used for protein structural studies. Traditionally, this technique involves protein labeling in D(2)O, followed by acid quenching, proteolytic digestion, and analysis of peptide deuteration levels by HPLC/MS. There is great interest in the development of alternative HDX approaches involving the top-down fragmentation of electrosprayed protein ions, instead of relying on enzymatic cleavage and solution-phase separations. A number of recent studies have demonstrated that electron capture dissociation (ECD) results in fragmentation of gaseous protein ions with little or no H/D scrambling. However, the successful application of this approach for in-depth protein conformational studies has not yet been demonstrated. The current work uses horse myoglobin as a model system for assessing the suitability of HDX-MS with top-down ECD for experiments of this kind. It is found that ECD can pinpoint the locations of protected amides with an average resolution of less than two residues for this 17 kDa protein. Native holo-myoglobin (hMb) shows considerable protection from exchange in all of its helices, whereas loops are extensively deuterated. Fraying is observable at some helix termini. Removal of the prosthetic heme group from hMb produces apo-myoglobin (aMb). Both hMb and aMb share virtually the same HDX protection pattern in helices A-E, whereas helix F is unfolded in aMb. In addition, destabilization is evident for some residues close to the beginning of helix G, the end of helix H, and the C-terminus of the protein. The structural changes reported herein are largely consistent with earlier NMR data for sperm whale myoglobin, although small differences between the two systems are evident. Our findings demonstrate that the level of structural information obtainable with top-down ECD for small to medium-sized proteins considerably surpasses that of traditional HDX-MS experiments, while at the same time greatly reducing

  1. Distinguishing of Ile/Leu amino acid residues in the PP3 protein by (hot) electron capture dissociation in Fourier transform ion cyclotron resonance mass spectrometry

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Haselmann, Kim F; Sørensen, Esben Skipper

    2003-01-01

    In hot electron capture dissociation (HECD), multiply protonated polypeptides fragment upon capturing approximately 11-eV electrons. The excess of energy upon the primary c, z* cleavage induces secondary fragmentation in z* fragments. The resultant w ions allow one to distinguish between the isom...

  2. First-principles investigation of the dissociation and coupling of methane on small copper clusters: Interplay of collision dynamics and geometric and electronic effects

    Energy Technology Data Exchange (ETDEWEB)

    Varghese, Jithin J.; Mushrif, Samir H., E-mail: shmushrif@ntu.edu.sg [School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 (Singapore)

    2015-05-14

    Small metal clusters exhibit unique size and morphology dependent catalytic activity. The search for alternate minimum energy pathways and catalysts to transform methane to more useful chemicals and carbon nanomaterials led us to investigate collision induced dissociation of methane on small Cu clusters. We report here for the first time, the free energy barriers for the collision induced activation, dissociation, and coupling of methane on small Cu clusters (Cu{sub n} where n = 2–12) using ab initio molecular dynamics and metadynamics simulations. The collision induced activation of the stretching and bending vibrations of methane significantly reduces the free energy barrier for its dissociation. Increase in the cluster size reduces the barrier for dissociation of methane due to the corresponding increase in delocalisation of electron density within the cluster, as demonstrated using the electron localisation function topology analysis. This enables higher probability of favourable alignment of the C–H stretching vibration of methane towards regions of high electron density within the cluster and makes higher number of sites available for the chemisorption of CH{sub 3} and H upon dissociation. These characteristics contribute in lowering the barrier for dissociation of methane. Distortion and reorganisation of cluster geometry due to high temperature collision dynamics disturb electron delocalisation within them and increase the barrier for dissociation. Coupling reactions of CH{sub x} (x = 1–3) species and recombination of H with CH{sub x} have free energy barriers significantly lower than complete dehydrogenation of methane to carbon. Thus, competition favours the former reactions at high hydrogen saturation on the clusters.

  3. First-principles investigation of the dissociation and coupling of methane on small copper clusters: Interplay of collision dynamics and geometric and electronic effects

    International Nuclear Information System (INIS)

    Varghese, Jithin J.; Mushrif, Samir H.

    2015-01-01

    Small metal clusters exhibit unique size and morphology dependent catalytic activity. The search for alternate minimum energy pathways and catalysts to transform methane to more useful chemicals and carbon nanomaterials led us to investigate collision induced dissociation of methane on small Cu clusters. We report here for the first time, the free energy barriers for the collision induced activation, dissociation, and coupling of methane on small Cu clusters (Cu n where n = 2–12) using ab initio molecular dynamics and metadynamics simulations. The collision induced activation of the stretching and bending vibrations of methane significantly reduces the free energy barrier for its dissociation. Increase in the cluster size reduces the barrier for dissociation of methane due to the corresponding increase in delocalisation of electron density within the cluster, as demonstrated using the electron localisation function topology analysis. This enables higher probability of favourable alignment of the C–H stretching vibration of methane towards regions of high electron density within the cluster and makes higher number of sites available for the chemisorption of CH 3 and H upon dissociation. These characteristics contribute in lowering the barrier for dissociation of methane. Distortion and reorganisation of cluster geometry due to high temperature collision dynamics disturb electron delocalisation within them and increase the barrier for dissociation. Coupling reactions of CH x (x = 1–3) species and recombination of H with CH x have free energy barriers significantly lower than complete dehydrogenation of methane to carbon. Thus, competition favours the former reactions at high hydrogen saturation on the clusters

  4. Tandem Mass Spectrometry on a Miniaturized Laser Desorption Time-of-Flight Mass Spectrometer

    Science.gov (United States)

    Li, Xiang; Cornish, Timothy; Getty, Stephanie A.; Brinckerhoff, William B.

    2016-01-01

    Tandem mass spectrometry (MSMS) is a powerful and widely-used technique for identifying the molecular structure of organic constituents of a complex sample. Application of MSMS to the study of unknown planetary samples on a remote space mission would contribute to our understanding of the origin, evolution, and distribution of extraterrestrial organics in our solar system. Here we report on the realization of MSMS on a miniaturized laser desorption time-of-flight mass spectrometer (LD-TOF-MS), which is one of the most promising instrument types for future planetary missions. This achievement relies on two critical components: a curved-field reflectron and a pulsed-pin ion gate. These enable use of the complementary post-source decay (PSD) and laser-assisted collision induced dissociation (L-CID) MSMS methods on diverse measurement targets with only modest investment in instrument resources such as volume and weight. MSMS spectra of selected molecular targets in various organic standards exhibit excellent agreement when compared with results from a commercial, laboratory-scale TOF instrument, demonstrating the potential of this powerful technique in space and planetary environments.

  5. Towards Liquid Chromatography Time-Scale Peptide Sequencing and Characterization of Post-Translational Modifications in the Negative-Ion Mode Using Electron Detachment Dissociation Tandem Mass Spectrometry

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Hørning, Ole B; Jensen, Søren S

    2008-01-01

    Electron detachment dissociation (EDD) of peptide poly-anions is gentle towards post-translational modifications (PTMs) and produces predictable and interpretable fragment ion types (a., x ions). However, EDD is considered an inefficient fragmentation technique and has not yet been implemented...... coverage and extended PTM characterization the new regime of EDD in combination with other ion-electron fragmentation techniques in the positive-ion mode is a step towards a more comprehensive strategy of analysis in proteome research....

  6. Petroleomics by Direct Analysis in Real Time-Mass Spectrometry.

    Science.gov (United States)

    Romão, Wanderson; Tose, Lilian V; Vaz, Boniek G; Sama, Sara G; Lobinski, Ryszard; Giusti, Pierre; Carrier, Hervé; Bouyssiere, Brice

    2016-01-01

    The analysis of crude oil and its fractions by applying ambient ionization techniques remains underexplored in mass spectrometry (MS). Direct analysis in real time (DART) in the positive-ion mode was coupled to a linear quadrupole ion trap Orbitrap mass spectrometer (LTQ Orbitrap) to analyze crude oil, paraffin samples, and porphyrin standard compounds. The ionization parameters of DART-MS were optimized for crude oil analysis. DART-MS rendered the optimum conditions of the operation using paper as the substrate, T = 400°C, helium as the carrier gas, and a sample concentration ≥6 mg mL(-1). In the crude oils analysis, the DART(+)-Orbitrap mass spectra detected the typical N, NO, and O-containing compounds. In the paraffin samples, oxidized hydrocarbon species (Ox classes, where x = 1-4) with double-bond equivalent of 1-4 were detected, and their structures and connectivity were confirmed by collision-induced dissociation (CID) experiments. DART(+)-MS has identified the porphyrin standard compounds as [M + H](+) ions of m/z 615.2502 and 680.1763, where M = C44H30N4 and C44H28N4OV, respectively, based on the formula assignment and by phenyl losses observed on CID experiments.

  7. Collision-Induced Infrared Absorption by Collisional Complexes in Dense Hydrogen-Helium Gas Mixtures at Thousands of Kelvin

    Science.gov (United States)

    Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

    2011-06-01

    The interaction-induced absorption by collisional pairs of H{_2} molecules is an important opacity source in the atmospheres of the outer planets and cool stars. The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H{_2}-H{_2}, H{_2}-He, and H{_2}-H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin. Laboratory measurements of interaction-induced absorption spectra by H{_2} pairs exist only at room temperature and below. We show that our results reproduce these measurements closely, so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures. L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 Xiaoping Li, Katharine L. C. Hunt, Fei Wang, Martin Abel, and Lothar Frommhold, "Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin", International Journal of Spectroscopy, vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201 M. Abel, L. Frommhold, X. Li, and K. L. C. Hunt, "Collision-induced absorption by H{_2} pairs: From hundreds to thousands of Kelvin," J. Phys. Chem. A, published online, DOI: 10.1021/jp109441f L. Frommhold, M. Abel, F. Wang, M. Gustafsson, X. Li, and K. L. C. Hunt, "Infrared atmospheric emission and absorption by simple molecular complexes, from first principles", Mol. Phys. 108, 2265, 2010

  8. Atmospheric pressure chemical ionization of fluorinated phenols in atmospheric pressure chemical ionization mass spectrometry, tandem mass spectrometry, and ion mobility spectrometry

    Science.gov (United States)

    Eiceman, G. A.; Bergloff, J. F.; Rodriguez, J. E.; Munro, W.; Karpas, Z.

    1999-01-01

    Atmospheric pressure chemical ionization (APCI)-mass spectrometry (MS) for fluorinated phenols (C6H5-xFxOH Where x = 0-5) in nitrogen with Cl- as the reagent ion yielded product ions of M Cl- through ion associations or (M-H)- through proton abstractions. Proton abstraction was controllable by potentials on the orifice and first lens, suggesting that some proton abstraction occurs through collision induced dissociation (CID) in the interface region. This was proven using CID of adduct ions (M Cl-) with Q2 studies where adduct ions were dissociated to Cl- or proton abstracted to (M-H)-. The extent of proton abstraction depended upon ion energy and structure in order of calculated acidities: pentafluorophenol > tetrafluorophenol > trifluorophenol > difluorophenol. Little or no proton abstraction occurred for fluorophenol, phenol, or benzyl alcohol analogs. Ion mobility spectrometry was used to determine if proton abstraction reactions passed through an adduct intermediate with thermalized ions and mobility spectra for all chemicals were obtained from 25 to 200 degrees C. Proton abstraction from M Cl- was not observed at any temperature for phenol, monofluorophenol, or difluorophenol. Mobility spectra for trifluorophenol revealed the kinetic transformations to (M-H)- either from M Cl- or from M2 Cl- directly. Proton abstraction was the predominant reaction for tetra- and penta-fluorophenols. Consequently, the evidence suggests that proton abstraction occurs from an adduct ion where the reaction barrier is reduced with increasing acidity of the O-H bond in C6H5-xFxOH.

  9. Collision-induced stimulated photon echo generated at transition 0-1 on broad spectral line conditions

    Science.gov (United States)

    Rubtsova, N. N.; Gol'dort, V. G.; Ishchenko, V. N.; Khvorostov, E. B.; Kochubei, S. A.; Borisov, G. M.; Ledovskikh, D. V.; Reshetov, V. A.

    2018-04-01

    For the first time, the collision induced stimulated photon echo generated at transition 1S0 → 3 P1 of 174Yb (type 0-1) in the mixture of gases Yb  +  Xe was investigated in the presence of weak longitudinal magnetic field, with experimental parameters corresponding to broad spectral line conditions. Comparison of the experimental echo amplitude versus magnetic field strength dependence with the theoretical curve shows a very good agreement, giving rise to an improved estimate for the difference between alignment and orientation decay rates.

  10. Histidine, lysine, and arginine radical cations: isomer control via the choice of auxiliary ligand (L) in the dissociation of [CuII(L)amino acid]*2+ complexes.

    Science.gov (United States)

    Ke, Yuyong; Zhao, Junfang; Verkerk, Udo H; Hopkinson, Alan C; Siu, K W Michael

    2007-12-27

    Histidine, lysine, and arginine radical cations have been generated through collision-induced dissociation (CID) of complexes [CuII(auxiliary ligand)namino acid]*2+, using tri-, bi-, as well as monodentate auxiliary ligands. On the basis of the observed CID products, the existence of two isomeric amino-acid populations is postulated. The Type 1 radical cations of histidine and lysine, stable on the mass spectrometer time scale, were found to lose water, followed by the loss of carbon monoxide under more energetic CID conditions. The arginine Type 1 radical cation behaved differently, losing dehydroalanine. The Type 2 radical cations were metastable and easily fragmented by the loss of carbon dioxide, effectively preventing direct observation. Type 1 radical cations are proposed to result from neutral (canonical) amino-acid coordination, whereas Type 2 radical cations are from zwitterionic amino-acid coordination to copper in the complex. The ratio of Type 1/Type 2 ions was found to be dependent on the auxiliary ligand, providing a method of controlling which radical cation would be formed primarily. Density functional calculations at B3LYP/6-311++G(d,p) have been used to determine the relative energies of five His*+ isomers. Barriers against interconversion between the isomers and against fragmentation have been calculated, giving insight as to why the Type 1 ions are stable, while only fragmentation products of the Type 2 ions are observable under CID conditions.

  11. Determination of Oxidized Phosphatidylcholines by Hydrophilic Interaction Liquid Chromatography Coupled to Fourier Transform Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Pia Sala

    2015-04-01

    Full Text Available A novel liquid chromatography-mass spectrometry (LC-MS approach for analysis of oxidized phosphatidylcholines by an Orbitrap Fourier Transform mass spectrometer in positive electrospray ionization (ESI coupled to hydrophilic interaction liquid chromatography (HILIC was developed. This method depends on three selectivity criteria for separation and identification: retention time, exact mass at a resolution of 100,000 and collision induced dissociation (CID fragment spectra in a linear ion trap. The process of chromatography development showed the best separation properties with a silica-based Kinetex column. This type of chromatography was able to separate all major lipid classes expected in mammalian samples, yielding increased sensitivity of oxidized phosphatidylcholines over reversed phase chromatography. Identification of molecular species was achieved by exact mass on intact molecular ions and CID tandem mass spectra containing characteristic fragments. Due to a lack of commercially available standards, method development was performed with copper induced oxidation products of palmitoyl-arachidonoyl-phosphatidylcholine, which resulted in a plethora of lipid species oxidized at the arachidonoyl moiety. Validation of the method was done with copper oxidized human low-density lipoprotein (LDL prepared by ultracentrifugation. In these LDL samples we could identify 46 oxidized molecular phosphatidylcholine species out of 99 possible candidates.

  12. Energy distribution in dissociations of polyatomic molecules

    International Nuclear Information System (INIS)

    Koernig, S.A.

    1989-01-01

    In this thesis studies are reported of fragmentation processes in polyatomic molecules. In order to find out which dessocaciation reactions take place, how they are brought about by the internal energy of the reactant, and to investigate the structure of the dissociating 'transition state', the fragment mass and the corresponding kinetic energy release (KER) are determined by differential translational spectroscopy using a position and time sensitive two-particle coincidence detector. The results are interpreted using the statistical theory of unimolecular dissociation. It turns out that the standard assumptions of the theory, especially in calculating KER-distributions, are not realistic in all molecules considered. Dissociation is induced by the neutralization with alkali metal vapour. In ch. 2 the experimental method and the analysis of the data (dissociation pathways, branching ratios and ε-d-distributions) are introduced and exemplified by measurements of cyclohexane, which represents the upper limit in precursor and fragment mass accessible in the apparatus. In ch. 3 a study is reported of the molecules methylchloride (CH 3 Cl) and the acetylradical (CH 3 CO). In spite of their similar geometric structures, completely different dissociation mechanisms have been found. Methylchloride dissociates via a repulsive state; acetyl radicals show energy scrambling. The energy distribution from dissociating acetyl exemplifies dynamical effects in the dissociation. In ch. 4 an investigation of a number of prototype hydrocarbons is presented. The dissociation pathways of several small linear alkanes indicate that neutralization takes place to unknown repulsive potentials, of which the position and steepness are determined from the kinetic energy release. (author). 118 refs.; 40 figs.; 5 tabs

  13. Dissociation in small molecules

    International Nuclear Information System (INIS)

    Dehmer, P.M.

    1982-01-01

    The study of molecular dissociation processes is one of the most interesting areas of modern spectroscopy owing to the challenges presented bt even the simplest of diatomic molecules. This paper reviews the commonly used descriptions of molecular dissociation processes for diatomic molecules, the selection rules for predissociation, and a few of the principles to be remembered when one is forced to speculate about dissociation mechanisms in a new molecule. Some of these points will be illustrated by the example of dissociative ionization in O 2

  14. Metal cation dependence of interactions with amino acids: bond dissociation energies of Rb(+) and Cs(+) to the acidic amino acids and their amide derivatives.

    Science.gov (United States)

    Armentrout, P B; Yang, Bo; Rodgers, M T

    2014-04-24

    Metal cation-amino acid interactions are key components controlling the secondary structure and biological function of proteins, enzymes, and macromolecular complexes comprising these species. Determination of pairwise interactions of alkali metal cations with amino acids provides a thermodynamic vocabulary that begins to quantify these fundamental processes. In the present work, we expand a systematic study of such interactions by examining rubidium and cesium cations binding with the acidic amino acids (AA), aspartic acid (Asp) and glutamic acid (Glu), and their amide derivatives, asparagine (Asn) and glutamine (Gln). These eight complexes are formed using electrospray ionization and their bond dissociation energies (BDEs) are determined experimentally using threshold collision-induced dissociation with xenon in a guided ion beam tandem mass spectrometer. Analyses of the energy-dependent cross sections include consideration of unimolecular decay rates, internal energy of the reactant ions, and multiple ion-neutral collisions. Quantum chemical calculations are conducted at the B3LYP, MP2(full), and M06 levels of theory using def2-TZVPPD basis sets, with results showing reasonable agreement with experiment. At 0 and 298 K, most levels of theory predict that the ground-state conformers for M(+)(Asp) and M(+)(Asn) involve tridentate binding of the metal cation to the backbone carbonyl, amino, and side-chain carbonyl groups, although tridentate binding to the carboxylic acid group and side-chain carbonyl is competitive for M(+)(Asn). For the two longer side-chain amino acids, Glu and Gln, multiple structures are competitive. A comparison of these results to those for the smaller alkali cations, Na(+) and K(+), provides insight into the trends in binding energies associated with the molecular polarizability and dipole moment of the side chain. For all four metal cations, the BDEs are inversely correlated with the size of the metal cation and follow the order Asp < Glu

  15. Catalytic methanol dissociation

    International Nuclear Information System (INIS)

    Alcinikov, Y.; Fainberg, V.; Garbar, A.; Gutman, M.; Hetsroni, G.; Shindler, Y.; Tatrtakovsky, L.; Zvirin, Y.

    1998-01-01

    Results of the methanol dissociation study on copper/potassium catalyst with alumina support at various temperatures are presented. The following gaseous and liquid products at. The catalytic methanol dissociation is obtained: hydrogen, carbon monoxide, carbon dioxide, methane, and dimethyl ether. Formation rates of these products are discussed. Activation energies of corresponding reactions are calculated

  16. Analysis of hydroxamate siderophores in soil solution using liquid chromatography with mass spectrometry and tandem mass spectrometry with on-line sample preconcentration.

    Science.gov (United States)

    Olofsson, Madelen A; Bylund, Dan

    2015-10-01

    A liquid chromatography with electrospray ionization mass spectrometry method was developed to quantitatively and qualitatively analyze 13 hydroxamate siderophores (ferrichrome, ferrirubin, ferrirhodin, ferrichrysin, ferricrocin, ferrioxamine B, D1 , E and G, neocoprogen I and II, coprogen and triacetylfusarinine C). Samples were preconcentrated on-line by a switch-valve setup prior to analyte separation on a Kinetex C18 column. Gradient elution was performed using a mixture of an ammonium formate buffer and acetonitrile. Total analysis time including column conditioning was 20.5 min. Analytes were fragmented by applying collision-induced dissociation, enabling structural identification by tandem mass spectrometry. Limit of detection values for the selected ion monitoring method ranged from 71 pM to 1.5 nM with corresponding values of two to nine times higher for the multiple reaction monitoring method. The liquid chromatography with mass spectrometry method resulted in a robust and sensitive quantification of hydroxamate siderophores as indicated by retention time stability, linearity, sensitivity, precision and recovery. The analytical error of the methods, assessed through random-order, duplicate analysis of soil samples extracted with a mixture of 10 mM phosphate buffer and methanol, appears negligible in relation to between-sample variations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Dissociation in mediation

    Directory of Open Access Journals (Sweden)

    Daniela Muraru

    2008-01-01

    Full Text Available This paper approaches several texts that are part of the so-called discourse of mediation, adopting a pragma-dialectical perspective of the theory of dissociation. It is an attempt to identify the uses of dissociative patterns, with special emphasis on the indicators of dissociation. The paper investigates the various uses of the concept of dissociation as a discursive technique in the argumentation on the different aspects that are involved in international conflict, such as the discussion of the notion of peace. The purpose is to identify the role of dissociation, as a device strategically used by the mediator to help the parties minimize the disagreement space, and come to a conflict resolution.

  18. A Variety of Activation Methods Employed in 'Activated-Ion' Electron Capture Dissociation Mass Spectrometry: A Test against Bovine Ubiquitin 7+ Ions

    International Nuclear Information System (INIS)

    Oh, Han Bin; McLafferty, Fred W.

    2006-01-01

    Fragmentation efficiencies of various 'activated-ion' electron capture dissociation (AI-ECD) methods are compared for a model system of bovine ubiquitin 7+ cations. In AI-ECD studies, sufficient internal energy was given to protein cations prior to ECD application using IR laser radiation, collisions, blackbody radiation, or in-beam collisions, in turn. The added energy was utilized in increasing the population of the precursor ions with less intra-molecular noncovalent bonds or enhancing thermal fluctuations of the protein cations. Removal of noncovalent bonds resulted in extended structures, which are ECD friendly. Under their best conditions, a variety of activation methods showed a similar effectiveness in ECD fragmentation. In terms of the number of fragmented inter-residue bonds, IR laser/blackbody infrared radiation and 'in-beam' activation were almost equally efficient with ∼70% sequence coverage, while collisions were less productive. In particular, 'in-beam' activation showed an excellent effectiveness in characterizing a pre-fractionated single kind of protein species. However, its inherent procedure did not allow for isolation of the protein cations of interest

  19. Gas-phase behaviour of Ru(II) cyclopentadienyl-derived complexes with N-coordinated ligands by electrospray ionization mass spectrometry: fragmentation pathways and energetics.

    Science.gov (United States)

    Madeira, Paulo J Amorim; Morais, Tânia S; Silva, Tiago J L; Florindo, Pedro; Garcia, M Helena

    2012-08-15

    The gas-phase behaviour of six Ru(II) cyclopentadienyl-derived complexes with N-coordinated ligands, compounds with antitumor activities against several cancer lines, was studied. This was performed with the intent of establishing fragmentation pathways and to determine the Ru-L(N) and Ru-L(P) ligand bond dissociation energies. Such knowledge can be an important tool for the postulation of the mechanisms of action of these anticancer drugs. Two types of instruments equipped with electrospray ionisation were used (ion trap and a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer). The dissociation energies were determined using energy-variable collision-induced dissociation measurements in the ion trap. The FTICR instrument was used to perform MS(n) experiments on one of the compounds and to obtain accurate mass measurements. Theoretical calculations were performed at the density functional theory (DFT) level using two different functionals (B3LYP and M06L) to estimate the dissociation energies of the complexes under study. The influence of the L(N) on the bond dissociation energy (D) of RuCp compounds with different nitrogen ligands was studied. The lability order of L(N) was: imidazole<1-butylimidazole<5-phenyl-1H-tetrazole<1-benzylimidazole. Both the functionals used gave the following ligand lability order: imidazole<1-benzylimidazole<5-phenyl-1H-tetrazole<1-butylimidazole. It is clear that there is an inversion between 1-benzylimidazole and 1-butylimidazole for the experimental and theoretical lability orders. The M06L functional afforded values of D closer to the experimental values. The type of phosphane (L(P) ) influenced the dissociation energies, with values of D being higher for Ru-L(N) with 1-butylimidazole when the phosphane was 1,2-bis(diphenylphosphino)ethane. The Ru-L(P) bond dissociation energy for triphenylphosphane was independent of the type of complex. The D values of Ru-L(N) and Ru-L(P) were determined for all six compounds and

  20. Investigation into the behavior of metal-argon polyatomic ions (MAr+) in the extraction region of inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Ebert, Chris H.; Witte, Travis M.; Houk, R.S.

    2012-01-01

    The abundances of metal-argon polyatomic ions (MAr + ) are determined in inductively coupled plasma-mass spectrometry (ICP-MS). The ratios of MAr + abundance to that for M + ions are measured experimentally. These ratios are compared to expected values, calculated for typical plasma conditions using spectroscopic data. For all metals studied (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn), the measured ratios are significantly lower than the calculated ratios. Increasing the plasma potential (and thereby increasing the ion kinetic energy) by means of a homemade guard electrode with a wide gap further reduces the MAr + /M + ratio. Implementing a skimmer cone designed for high transmission of light ions increases the MAr + abundance. Considering this evidence, the scarcity of MAr + ions is attributed to collision induced dissociation (CID), likely due to a shock wave at the tip of or in the throat of the skimmer cone. - Highlights: ► MAr + ions are less abundant in the mass spectrum than expected from the ICP. ► Increasing the plasma potential reduces their abundance further. ► The extraction lens voltage does not greatly affect the MAr + abundances. ► The weakly-bound MAr + ions are probably dissociated by collisions during extraction.

  1. Collision-induced absorption by D2 pairs in the first overtone band at 77, 201 and 298 K

    International Nuclear Information System (INIS)

    Abu-Kharma, M.; Gillard, P.G.; Reddy, S.P.

    2006-01-01

    Collision induced absorption (CIA) spectra of pure D 2 in the first overtone region from 5250 to 7250 cm -1 , recorded at 77, 201 and 298 K, have been analyzed. The observed spectra at 77, 201 and 298 K were modelled by a total of 92, 214 and 267 components respectively of double vibrational transitions at room temperature of the type X 2 (J) +X 0 (J) and X 1 (J) + X 1 (J), where X is O, Q or S transitions. Profile analyses of the spectra were carried out using the Birnbaum-Cohen line-shape function for the individual components of the band, and characteristic line shape parameters were determined from the analysis. The observed and calculated profiles agree well over the whole overtone band, and the agreement is better than 97% in the three cases studied. Binary and ternary absorption coefficients were determined from the integrated absorption of the band. (authors)

  2. Further Study of Λ-Related Quantum Interference of Π-State Diatomic on Collision-Induced Rotational Energy Transfer

    International Nuclear Information System (INIS)

    Li Yongqing; Song Peng; Chen Yuehui; Wang Weili; Ma Fengcai

    2005-01-01

    In our previous theoretical studies [Meng-Tao Sun, Yong-Qing Lee, and Feng-Cai Ma, Chem. Phys. Lett. 371 (2003) 342], we have reported the quantum interference on collision-induced rotational energy transfer on CO (A 1 Π, v = 3) with inert gases, which originates from the difference between the two Λ-related collision potential energy surfaces. The interference angle, which measures the degree of coherence, is presented in this paper. Based on the time-dependent first order Born approximation, taking into account the anisotropic Lennard-Jones interaction potentials, the relation of the interference angle with the factors, including experimental temperature, partner, and rotational quantum number, are obtained. The changing tendencies with them are discussed. This theoretical model is important to understanding and performing this kind of experiment.

  3. Unified first principles description from warm dense matter to ideal ionized gas plasma: electron-ion collisions induced friction.

    Science.gov (United States)

    Dai, Jiayu; Hou, Yong; Yuan, Jianmin

    2010-06-18

    Electron-ion interactions are central to numerous phenomena in the warm dense matter (WDM) regime and at higher temperature. The electron-ion collisions induced friction at high temperature is introduced in the procedure of ab initio molecular dynamics using the Langevin equation based on density functional theory. In this framework, as a test for Fe and H up to 1000 eV, the equation of state and the transition of electronic structures of the materials with very wide density and temperature can be described, which covers a full range of WDM up to high energy density physics. A unified first principles description from condensed matter to ideal ionized gas plasma is constructed.

  4. Effects of momentum-dependent symmetry potential on heavy-ion collisions induced by neutron-rich nuclei

    International Nuclear Information System (INIS)

    Li Baoan; Das, Champak B.; Das Gupta, Subal; Gale, Charles

    2004-01-01

    Using an isospin- and momentum-dependent transport model we study effects of the momentum-dependent symmetry potential on heavy-ion collisions induced by neutron-rich nuclei. It is found that symmetry potentials with and without the momentum-dependence but corresponding to the same density-dependent symmetry energy E sym (ρ) lead to significantly different predictions on several E sym (ρ)-sensitive experimental observables especially for energetic nucleons. The momentum- and density-dependence of the symmetry potential have to be determined simultaneously in order to extract the E sym (ρ) accurately. The isospin asymmetry of midrapidity nucleons at high transverse momenta is particularly sensitive to the momentum-dependence of the symmetry potential. It is thus very useful for investigating accurately the equation of state of dense neutron-rich matter

  5. Versatile lipid profiling by liquid chromatography–high resolution mass spectrometry using all ion fragmentation and polarity switching. Preliminary application for serum samples phenotyping related to canine mammary cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gallart-Ayala, H., E-mail: laberca@oniris-nantes.fr [LUNAM, Ecole Nationale Vétérinaire, Agroalimentaire et de l’Alimentation Nantes Atlantique (Oniris), USC 1329 INRA Laboratoire d’Etude des résidus et Contaminants dans les Aliments (LABERCA), Site de la Chantrerie – CS50707, 44307 Nantes cedex 3 (France); Courant, F.; Severe, S.; Antignac, J.-P. [LUNAM, Ecole Nationale Vétérinaire, Agroalimentaire et de l’Alimentation Nantes Atlantique (Oniris), USC 1329 INRA Laboratoire d’Etude des résidus et Contaminants dans les Aliments (LABERCA), Site de la Chantrerie – CS50707, 44307 Nantes cedex 3 (France); Morio, F.; Abadie, J. [LUNAM, Ecole Nationale Vétérinaire, Agroalimentaire et de l’Alimentation Nantes Atlantique (Oniris), Cancers Animaux, Modèles pour la Recherche en Oncologie Comparée (AMaROC), Site de la Chantrerie–CS50707, 44307 Nantes cedex 3 (France); Le Bizec, B. [LUNAM, Ecole Nationale Vétérinaire, Agroalimentaire et de l’Alimentation Nantes Atlantique (Oniris), USC 1329 INRA Laboratoire d’Etude des résidus et Contaminants dans les Aliments (LABERCA), Site de la Chantrerie – CS50707, 44307 Nantes cedex 3 (France)

    2013-09-24

    Graphical abstract: -- Highlights: •Lipidomics, high resolution mass spectrometry, polarity switching, serum, canine mammary cancer. -- Abstract: Lipids represent an extended class of substances characterized by such high variety and complexity that makes their unified analyses by liquid chromatography coupled to either high resolution or tandem mass spectrometry (LC–HRMS or LC–MS/MS) a real challenge. In the present study, a new versatile methodology associating ultra high performance liquid chromatography coupled to high resolution tandem mass spectrometry (UHPLC–HRMS/MS) have been developed for a comprehensive analysis of lipids. The use of polarity switching and “all ion fragmentation” (AIF) have been two action levels particularly exploited to finally permit the detection and identification of a multi-class and multi-analyte extended range of lipids in a single run. For identification purposes, both higher energy collision dissociation (HCD) and in-source CID (collision induced dissociation) fragmentation were evaluated in order to obtain information about the precursor and product ions in the same spectra. This approach provides both class-specific and lipid-specific fragments, enhancing lipid identification. Finally, the developed method was applied for differential phenotyping of serum samples collected from pet dogs developing spontaneous malignant mammary tumors and health controls. A biological signature associated with the presence of cancer was then successfully revealed from this lipidome analysis, which required to be further investigated and confirmed at larger scale.

  6. Versatile lipid profiling by liquid chromatography–high resolution mass spectrometry using all ion fragmentation and polarity switching. Preliminary application for serum samples phenotyping related to canine mammary cancer

    International Nuclear Information System (INIS)

    Gallart-Ayala, H.; Courant, F.; Severe, S.; Antignac, J.-P.; Morio, F.; Abadie, J.; Le Bizec, B.

    2013-01-01

    Graphical abstract: -- Highlights: •Lipidomics, high resolution mass spectrometry, polarity switching, serum, canine mammary cancer. -- Abstract: Lipids represent an extended class of substances characterized by such high variety and complexity that makes their unified analyses by liquid chromatography coupled to either high resolution or tandem mass spectrometry (LC–HRMS or LC–MS/MS) a real challenge. In the present study, a new versatile methodology associating ultra high performance liquid chromatography coupled to high resolution tandem mass spectrometry (UHPLC–HRMS/MS) have been developed for a comprehensive analysis of lipids. The use of polarity switching and “all ion fragmentation” (AIF) have been two action levels particularly exploited to finally permit the detection and identification of a multi-class and multi-analyte extended range of lipids in a single run. For identification purposes, both higher energy collision dissociation (HCD) and in-source CID (collision induced dissociation) fragmentation were evaluated in order to obtain information about the precursor and product ions in the same spectra. This approach provides both class-specific and lipid-specific fragments, enhancing lipid identification. Finally, the developed method was applied for differential phenotyping of serum samples collected from pet dogs developing spontaneous malignant mammary tumors and health controls. A biological signature associated with the presence of cancer was then successfully revealed from this lipidome analysis, which required to be further investigated and confirmed at larger scale

  7. Lithium formate ion clusters formation during electrospray ionization: Evidence of magic number clusters by mass spectrometry and ab initio calculations

    International Nuclear Information System (INIS)

    Shukla, Anil; Bogdanov, Bogdan

    2015-01-01

    Small cationic and anionic clusters of lithium formate were generated by electrospray ionization and their fragmentations were studied by tandem mass spectrometry (collision-induced dissociation with N 2 ). Singly as well as multiply charged clusters were formed in both positive and negative ion modes with the general formulae, (HCOOLi) n Li + , (HCOOLi) n Li m m+ , (HCOOLi) n HCOO − , and (HCOOLi) n (HCOO) m m− . Several magic number cluster (MNC) ions were observed in both the positive and negative ion modes although more predominant in the positive ion mode with (HCOOLi) 3 Li + being the most abundant and stable cluster ion. Fragmentations of singly charged positive clusters proceed first by the loss of a dimer unit ((HCOOLi) 2 ) followed by the loss of monomer units (HCOOLi) although the former remains the dominant dissociation process. In the case of positive cluster ions, all fragmentations lead to the magic cluster (HCOOLi) 3 Li + as the most abundant fragment ion at higher collision energies which then fragments further to dimer and monomer ions at lower abundances. In the negative ion mode, however, singly charged clusters dissociated via sequential loss of monomer units. Multiply charged clusters in both positive and negative ion modes dissociated mainly via Coulomb repulsion. Quantum chemical calculations performed for smaller cluster ions showed that the trimer ion has a closed ring structure similar to the phenalenylium structure with three closed rings connected to the central lithium ion. Further additions of monomer units result in similar symmetric structures for hexamer and nonamer cluster ions. Thermochemical calculations show that trimer cluster ion is relatively more stable than neighboring cluster ions, supporting the experimental observation of a magic number cluster with enhanced stability

  8. Electrospray ionization mass spectrometry for the hydrolysis complexes of cisplatin: implications for the hydrolysis process of platinum complexes.

    Science.gov (United States)

    Feifan, Xie; Pieter, Colin; Jan, Van Bocxlaer

    2017-07-01

    Non-enzyme-dependent hydrolysis of the drug cisplatin is important for its mode of action and toxicity. However, up until today, the hydrolysis process of cisplatin is still not completely understood. In the present study, the hydrolysis of cisplatin in an aqueous solution was systematically investigated by using electrospray ionization mass spectrometry coupled to liquid chromatography. A variety of previously unreported hydrolysis complexes corresponding to monomeric, dimeric and trimeric species were detected and identified. The characteristics of the Pt-containing complexes were investigated by using collision-induced dissociation (CID). The hydrolysis complexes demonstrate distinctive and correlative CID characteristics, which provides tools for an informative identification. The most frequently observed dissociation mechanism was sequential loss of NH 3 , H 2 O and HCl. Loss of the Pt atom was observed as the final step during the CID process. The formation mechanisms of the observed complexes were explored and experimentally examined. The strongly bound dimeric species, which existed in solution, are assumed to be formed from the clustering of the parent compound and its monohydrated or dihydrated complexes. The role of the electrospray process in the formation of some of the observed ions was also evaluated, and the electrospray ionization-related cold clusters were identified. The previously reported hydrolysis equilibria were tested and subsequently refined via a hydrolysis study resulting in a renewed mechanistic equilibrium system of cisplatin as proposed from our results. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  9. Applications of Tandem Mass Spectrometry in the Structure Determination of Permethylated Sialic Acid-containing Oligosaccharides

    International Nuclear Information System (INIS)

    Yoo, Eun Sun; Yoon, In Mo

    2005-01-01

    Sets of sialic acid-containing trisaccharides having different internal and terminal linkages have been synthesized to develop a sensitive method for analysis of the reducing terminal linkage positions. The trisaccharides, sialyl(α 2-3)Gal(β 1-3)GalNAc and sialyl(α 2-3)Gal(β 1-X)GlcNAc where X=3, 4 and 6, were synthesized and examined using electrospray ionization (ESI)-collision induced dissociation (CID) tandem mass spectrometry (MS/MS). The compounds chosen for this study are related to terminal groups likely to be found on polylactosamine-like glycoproteins and glycolipids which occur on the surface of mammalian cells. The purpose of this study is to develop tandem mass spectrometral methods to determine detailed carbohydrate structures on permethylated or partially methylated oligosaccharides for future applications on biologically active glycoconjugates and to exploit a faster method of synthesizing a series of structural isomeric oligosaccharides to be used for further mass spectrometry and instrumental analysis

  10. [Probabilistic calculations of biomolecule charge states that generate mass spectra of multiply charged ions].

    Science.gov (United States)

    Raznikova, M O; Raznikov, V V

    2015-01-01

    In this work, information relating to charge states of biomolecule ions in solution obtained using the electrospray ionization mass spectrometry of different biopolymers is analyzed. The data analyses have mainly been carried out by solving an inverse problem of calculating the probabilities of retention of protons and other charge carriers by ionogenic groups of biomolecules with known primary structures. The approach is a new one and has no known to us analogues. A program titled "Decomposition" was developed and used to analyze the charge distribution of ions of native and denatured cytochrome c mass spectra. The possibility of splitting of the charge-state distribution of albumin into normal components, which likely corresponds to various conformational states of the biomolecule, has been demonstrated. The applicability criterion for using previously described method of decomposition of multidimensional charge-state distributions with two charge carriers, e.g., a proton and a sodium ion, to characterize the spatial structure of biopolymers in solution has been formulated. In contrast to known mass-spectrometric approaches, this method does not require the use of enzymatic hydrolysis or collision-induced dissociation of the biopolymers.

  11. LESSONS IN DE NOVO PEPTIDE SEQUENCING BY TANDEM MASS SPECTROMETRY

    Science.gov (United States)

    Medzihradszky, Katalin F.; Chalkley, Robert J.

    2015-01-01

    Mass spectrometry has become the method of choice for the qualitative and quantitative characterization of protein mixtures isolated from all kinds of living organisms. The raw data in these studies are MS/MS spectra, usually of peptides produced by proteolytic digestion of a protein. These spectra are “translated” into peptide sequences, normally with the help of various search engines. Data acquisition and interpretation have both been automated, and most researchers look only at the summary of the identifications without ever viewing the underlying raw data used for assignments. Automated analysis of data is essential due to the volume produced. However, being familiar with the finer intricacies of peptide fragmentation processes, and experiencing the difficulties of manual data interpretation allow a researcher to be able to more critically evaluate key results, particularly because there are many known rules of peptide fragmentation that are not incorporated into search engine scoring. Since the most commonly used MS/MS activation method is collision-induced dissociation (CID), in this article we present a brief review of the history of peptide CID analysis. Next, we provide a detailed tutorial on how to determine peptide sequences from CID data. Although the focus of the tutorial is de novo sequencing, the lessons learned and resources supplied are useful for data interpretation in general. PMID:25667941

  12. Studies of neutron dissociation at Fermilab energies

    International Nuclear Information System (INIS)

    Ferbel, T.

    1975-01-01

    The latest results obtained in a continuing investigation of neutron dissociation in (pπ - ) systems in neutron--nucleus collisions between 50 and 300 GeV/c are summarized. The nuclear coherent dissociation data are discussed first; then new measurements of total cross sections of neutrons on nuclei in the Fermilab momentum range are presented; finally, neutron dissociation using a hydrogen target is considered, and the hydrogen data are compared with expectations from simple Deck models. A substantial correlation was observed between the mass and the t of the system produced. The spin structure of the pπ - amplitudes at low mass was described surprisingly well by the simple Deck mechanism. The t-channel helicity amplitudes contained comparable contributions from flip and nonflip terms, and the states produced were not restricted to those expected on the basis of the Morrison rule. (19 figures, 2 tables) (U.S.)

  13. Complete characterization of posttranslational modification sites in the bovine milk protein PP3 by tandem mass spectrometry with electron capture dissociation as the last stage

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Haselmann, Kim F; Budnik, Bogdan A

    2003-01-01

    the PTM site. Chromatographic peak analysis continues until full sequence coverage is obtained, after which the molecular mass is reconstructed and compared with the measured value. An agreement indicates that the PTM characterization was complete. This procedure applied to the bovine milk PP3 protein...

  14. Probing the Conformational and Functional Consequences of Disulfide Bond Engineering in Growth Hormone by Hydrogen-Deuterium Exchange Mass Spectrometry Coupled to Electron Transfer Dissociation

    DEFF Research Database (Denmark)

    Seger, Signe T; Breinholt, Jens; Faber, Johan H

    2015-01-01

    Human growth hormone (hGH), and its receptor interaction, is essential for cell growth. To stabilize a flexible loop between helices 3 and 4, while retaining affinity for the hGH receptor, we have engineered a new hGH variant (Q84C/Y143C). Here, we employ hydrogen-deuterium exchange mass spectrom......Human growth hormone (hGH), and its receptor interaction, is essential for cell growth. To stabilize a flexible loop between helices 3 and 4, while retaining affinity for the hGH receptor, we have engineered a new hGH variant (Q84C/Y143C). Here, we employ hydrogen-deuterium exchange mass...

  15. Mass defect filtering-oriented classification and precursor ions list-triggered high-resolution mass spectrometry analysis for the discovery of indole alkaloids from Uncaria sinensis.

    Science.gov (United States)

    Pan, Huiqin; Yang, Wenzhi; Yao, Changliang; Shen, Yao; Zhang, Yibei; Shi, Xiaojian; Yao, Shuai; Wu, Wanying; Guo, Dean

    2017-09-22

    Discovery of new natural compounds is becoming increasingly challenging because of the interference from those known and abundant components. The aim of this study is to report a dereplication strategy, by integrating mass defect filtering (MDF)-oriented novelty classification and precursor ions list (PIL)-triggered high-resolution mass spectrometry analysis, and to validate it by discovering new indole alkaloids from the medicinal herb Uncaria sinensis. Rapid chromatographic separation was achieved on a Kinetex ® EVO C18 column (<16min). An in-house MDF algorithm, developed based on the informed phytochemistry information and molecular design, could more exactly screen the target alkaloids and divide them into three novelty levels: Known (KN), Unknown-but-Predicted (UP), and Unexpected (UN). A hybrid data acquisition method, namely PIL-triggered collision-induced dissociation-MS 2 and high-energy C-trap dissociation-MS 3 with dynamic exclusion on a linear ion trap/Orbitrap mass spectrometer, facilitated the acquisition of diverse product ions sufficient for the structural elucidation of both indole alkaloids and the N-oxides. Ultimately, 158 potentially new alkaloids, including 10 UP and 108 UN, were rapidly characterized from the stem, leaf, and flower of U. sinensis. Two new alkaloid compounds thereof were successfully isolated and identified by 1D and 2D NMR analyses. The varied ring E and novel alkaloid-acylquinic acid conjugates were first reported from the whole Uncaria genus. Conclusively, it is a practical chemical dereplication strategy that can enhance the efficiency and has the potential to be a routine approach for the discovery of new natural compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Utility of Higher Harmonics in Electrospray Ionization Fourier Transform Electrostatic Linear Ion Trap Mass Spectrometry.

    Science.gov (United States)

    Dziekonski, Eric T; Johnson, Joshua T; McLuckey, Scott A

    2017-04-18

    Mass resolution (M/ΔM fwhm) is observed to linearly increase with harmonic order in a Fourier transform electrostatic linear ion trap (ELIT) mass spectrometer. This behavior was predicted by Grosshans and Marshall for frequency-multiple detection in a Fourier transform ion cyclotron resonance mass spectrometer only for situations when the prominent mechanism for signal decay is ion ejection from the trap. As the analyzer pressure in our ELIT chamber is relatively high, such that collisional scattering and collision-induced dissociation are expected to underlie much of the ion loss, we sought to explore the relationship between harmonic order and mass resolution. Mass resolutions of 36 900 (fundamental), 75 850 (2nd harmonic), and 108 200 (3rd harmonic) were obtained for GdO + (avg. m/z 173.919) with a transient length of 300 ms. To demonstrate that the mass resolution was truly increasing with harmonic order, the unresolved isotopes at the fundamental distribution of cytochrome c +8 (m/z ∼ 1549) were nearly baseline, resolved at the third harmonic (mass resolution ≈ 23 000) with a transient length of only 200 ms. This experiment demonstrates that, when the ion density is sufficiently low, ions with frequency differences of less than 4 Hz remain uncoalesced. Higher harmonics can be used to increase the effective mass resolution for a fixed transient length and thereby may enable the resolution of closely spaced masses, determination of a protein ion's charge state, and study of the onset of peak coalescence when the resolution at the fundamental frequency is insufficient.

  17. Fragmentation pathways and structural characterization of organophosphorus compounds related to the Chemical Weapons Convention by electron ionization and electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Hosseini, Seyed Esmaeil; Saeidian, Hamid; Amozadeh, Ali; Naseri, Mohammad Taghi; Babri, Mehran

    2016-12-30

    For unambiguous identification of Chemical Weapons Convention (CWC)-related chemicals in environmental samples, the availability of mass spectra, interpretation skills and rapid microsynthesis of suspected chemicals are essential requirements. For the first time, the electron ionization single quadrupole and electrospray ionization tandem mass spectra of a series of O-alkyl N-[bis(dimethylamino)methylidene]-P-methylphosphonamidates (Scheme 1, cpd 4) were studied for CWC verification purposes. O-Alkyl N-[bis(dimethylamino)methylidene]-P-methylphosphonamidates were prepared through a microsynthetic method and were analyzed using electron ionization and electrospray ionization mass spectrometry with gas and liquid chromatography, respectively, as MS-inlet systems. General EI and ESI fragmentation pathways were proposed and discussed, and collision-induced dissociation studies of the protonated derivatives of these compounds were performed to confirm proposed fragment ion structures by analyzing mass spectra of deuterated analogs. Mass spectrometric studies revealed some interesting fragmentation pathways during the ionization process, such as McLafferty rearrangement, hydrogen rearrangement and a previously unknown intramolecular electrophilic aromatic substitution reaction. The EI and ESI fragmentation routes of the synthesized compounds 4 were investigated with the aim of detecting and identifying CWC-related chemicals during on-site inspection and/or off-site analysis and toxic chemical destruction monitoring. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Versatile lipid profiling by liquid chromatography-high resolution mass spectrometry using all ion fragmentation and polarity switching. Preliminary application for serum samples phenotyping related to canine mammary cancer.

    Science.gov (United States)

    Gallart-Ayala, H; Courant, F; Severe, S; Antignac, J-P; Morio, F; Abadie, J; Le Bizec, B

    2013-09-24

    Lipids represent an extended class of substances characterized by such high variety and complexity that makes their unified analyses by liquid chromatography coupled to either high resolution or tandem mass spectrometry (LC-HRMS or LC-MS/MS) a real challenge. In the present study, a new versatile methodology associating ultra high performance liquid chromatography coupled to high resolution tandem mass spectrometry (UHPLC-HRMS/MS) have been developed for a comprehensive analysis of lipids. The use of polarity switching and "all ion fragmentation" (AIF) have been two action levels particularly exploited to finally permit the detection and identification of a multi-class and multi-analyte extended range of lipids in a single run. For identification purposes, both higher energy collision dissociation (HCD) and in-source CID (collision induced dissociation) fragmentation were evaluated in order to obtain information about the precursor and product ions in the same spectra. This approach provides both class-specific and lipid-specific fragments, enhancing lipid identification. Finally, the developed method was applied for differential phenotyping of serum samples collected from pet dogs developing spontaneous malignant mammary tumors and health controls. A biological signature associated with the presence of cancer was then successfully revealed from this lipidome analysis, which required to be further investigated and confirmed at larger scale. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Detection of Low Molecular Weight Adulterants in Beverages by Direct Analysis in Real Time Mass Spectrometry.

    Science.gov (United States)

    Sisco, Edward; Dake, Jeffrey

    2016-04-14

    Direct Analysis in Real Time Mass Spectrometry (DART-MS) has been used to detect the presence of non-narcotic adulterants in beverages. The non-narcotic adulterants that were examined in this work incorporated a number low molecular weight alcohols, acetone, ammonium hydroxide, and sodium hypochlorite. Analysis of the adulterants was completed by pipetting 1 µL deposits onto glass microcapillaries along with an appropriate dopant species followed by introduction into the DART gas stream. It was found that detection of these compounds in the complex matrices of common beverages (soda, energy drinks, etc.) was simplified through the use of a dopant species to allow for adduct formation with the desired compound(s) of interest. Other parameters that were investigated included DART gas stream temperature, in source collision induced dissociation, ion polarity, and DART needle voltage. Sensitivities of the technique were found to range from 0.001 % volume fraction to 0.1 % volume fraction, comparable to traditional analyses completed using headspace gas chromatography mass spectrometry (HS-GC/MS). Once a method was established using aqueous solutions, , fifteen beverages were spiked with each of the nine adulterants, to simulate real world detection, and in nearly all cases the adulterant could be detected either in pure form, or complexed with the added dopant species. This technique provides a rapid way to directly analyze beverages believed to be contaminated with non-narcotic adulterants at sensitivities similar to or exceeding those of traditional confirmatory analyses.

  20. Correlations in the hadronic double diffractive dissociation; Correlacoes na dupla dissociacao difrativa hadronica

    Energy Technology Data Exchange (ETDEWEB)

    Goldegol, Alexandre

    1991-05-01

    A given reaction of double diffractive dissociation is studied based on the three-component Deck Model. The correlations among the diffractive slope, the effective mass of the dissociated particle sub-system and the dissociation angle in the Gottfried-Jackson are studied based in this model. 9 refs, 19 figs.

  1. Dissociation Behavior of a TEMPO-Active Ester Cross-Linker for Peptide Structure Analysis by Free Radical Initiated Peptide Sequencing (FRIPS) in Negative ESI-MS.

    Science.gov (United States)

    Hage, Christoph; Ihling, Christian H; Götze, Michael; Schäfer, Mathias; Sinz, Andrea

    2017-01-01

    We have synthesized a homobifunctional amine-reactive cross-linking reagent, containing a TEMPO (2,2,6,6-tetramethylpiperidine-1-oxy) and a benzyl group (Bz), termed TEMPO-Bz-linker, to derive three-dimensional structural information of proteins. The aim for designing this novel cross-linker was to facilitate the mass spectrometric analysis of cross-linked products by free radical initiated peptide sequencing (FRIPS). In an initial study, we had investigated the fragmentation behavior of TEMPO-Bz-derivatized peptides upon collision activation in (+)-electrospray ionization collision-induced dissociation tandem mass spectrometry (ESI-CID-MS/MS) experiments. In addition to the homolytic NO-C bond cleavage FRIPS pathway delivering the desired odd-electron product ions, an alternative heterolytic NO-C bond cleavage, resulting in even-electron product ions mechanism was found to be relevant. The latter fragmentation route clearly depends on the protonation of the TEMPO-Bz-moiety itself, which motivated us to conduct (-)-ESI-MS, CID-MS/MS, and MS 3 experiments of TEMPO-Bz-cross-linked peptides to further clarify the fragmentation behavior of TEMPO-Bz-peptide molecular ions. We show that the TEMPO-Bz-linker is highly beneficial for conducting FRIPS in negative ionization mode as the desired homolytic cleavage of the NO-C bond is the major fragmentation pathway. Based on characteristic fragments, the isomeric amino acids leucine and isoleucine could be discriminated. Interestingly, we observed pronounced amino acid side chain losses in cross-linked peptides if the cross-linked peptides contain a high number of acidic amino acids. Graphical Abstract ᅟ.

  2. Top Down Tandem Mass Spectrometric Analysis of a Chemically Modified Rough-Type Lipopolysaccharide Vaccine Candidate

    Science.gov (United States)

    Oyler, Benjamin L.; Khan, Mohd M.; Smith, Donald F.; Harberts, Erin M.; Kilgour, David P. A.; Ernst, Robert K.; Cross, Alan S.; Goodlett, David R.

    2018-02-01

    Recent advances in lipopolysaccharide (LPS) biology have led to its use in drug discovery pipelines, including vaccine and vaccine adjuvant discovery. Desirable characteristics for LPS vaccine candidates include both the ability to produce a specific antibody titer in patients and a minimal host inflammatory response directed by the innate immune system. However, in-depth chemical characterization of most LPS extracts has not been performed; hence, biological activities of these extracts are unpredictable. Additionally, the most widely adopted workflow for LPS structure elucidation includes nonspecific chemical decomposition steps before analyses, making structures inferred and not necessarily biologically relevant. In this work, several different mass spectrometry workflows that have not been previously explored were employed to show proof-of-principle for top down LPS primary structure elucidation, specifically for a rough-type mutant (J5) E. coli-derived LPS component of a vaccine candidate. First, ion mobility filtered precursor ions were subjected to collision induced dissociation (CID) to define differences in native J5 LPS v. chemically detoxified J5 LPS (dLPS). Next, ultra-high mass resolving power, accurate mass spectrometry was employed for unequivocal precursor and product ion empirical formulae generation. Finally, MS3 analyses in an ion trap instrument showed that previous knowledge about dissociation of LPS components can be used to reconstruct and sequence LPS in a top down fashion. A structural rationale is also explained for differential inflammatory dose-response curves, in vitro, when HEK-Blue hTLR4 cells were administered increasing concentrations of native J5 LPS v. dLPS, which will be useful in future drug discovery efforts. [Figure not available: see fulltext.

  3. Investigation of some biologically relevant redox reactions using electrochemical mass spectrometry interfaced by desorption electrospray ionization.

    Science.gov (United States)

    Lu, Mei; Wolff, Chloe; Cui, Weidong; Chen, Hao

    2012-04-01

    Recently we have shown that, as a versatile ionization technique, desorption electrospray ionization (DESI) can serve as a useful interface to combine electrochemistry (EC) with mass spectrometry (MS). In this study, the EC/DESI-MS method has been further applied to investigate some aqueous phase redox reactions of biological significance, including the reduction of peptide disulfide bonds and nitroaromatics as well as the oxidation of phenothiazines. It was found that knotted/enclosed disulfide bonds in the peptides apamin and endothelin could be electrochemically cleaved. Subsequent tandem MS analysis of the resulting reduced peptide ions using collision-induced dissociation (CID) and electron-capture dissociation (ECD) gave rise to extensive fragment ions, providing a fast protocol for sequencing peptides with complicated disulfide bond linkages. Flunitrazepam and clonazepam, a class of nitroaromatic drugs, are known to undergo reduction into amines which was proposed to involve nitroso and N-hydroxyl intermediates. Now in this study, these corresponding intermediate ions were successfully intercepted and their structures were confirmed by CID. This provides mass spectrometric evidence for the mechanism of the nitro to amine conversion process during nitroreduction, an important redox reaction involved in carcinogenesis. In addition, the well-known oxidation reaction of chlorpromazine was also examined. The putative transient one-electron transfer product, the chlorpromazine radical cation (m/z 318), was captured by MS, for the first time, and its structure was also verified by CID. In addition to these observations, some features of the DESI-interfaced electrochemical mass spectrometry were discussed, such as simple instrumentation and the lack of background signal. These results further demonstrate the feasibility of EC/DESI-MS for the study of the biology-relevant redox chemistry and would find applications in proteomics and drug development research.

  4. Quantification of citalopram or escitalopram and their demethylated metabolites in neonatal hair samples by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Frison, Giampietro; Favretto, Donata; Vogliardi, Susanna; Terranova, Claudio; Ferrara, Santo Davide

    2008-08-01

    Citalopram and escitalopram are highly selective serotonin reuptake inhibitors widely used in the treatment of depression. They exhibit adverse drug reactions and side effects, however, and the development of specific methods for their determination is of great interest in clinical and forensic toxicology. A liquid chromatography-tandem mass spectrometry method has been developed and validated for the assay of citalopram, escitalopram, and their demethylated metabolites in 10-mg hair samples. The analytes were extracted by incubation in methanol and liquid/liquid extraction with diethyl ether/dichloromethane. Gradient elution on a narrow bore C18 column was realized using clomipramine-d3 as an internal standard. Positive ion electrospray ionization and tandem mass spectrometry determination by collision-induced dissociation were performed in an ion trap mass spectrometer. The method exhibited a linear range of 25 to 2000 pg/mg, a quantification limit of 25 pg/mg for all analytes, relative standard deviations in the range of 12.10 to 9.80 (intraassay), and 13.80 to 11.78 (interassay), and accuracies (as percent recovery of the spiked standards) in the range of 90% to 110%; it was applied to the determination of citalopram and escitalopram and their metabolites in hair samples of two newborns to document their in utero exposure to the drugs. The method proved suitable for neonatal hair analysis of citalopram or escitalopram and was applied to two real cases of gestational exposure.

  5. An analytical platform for mass spectrometry-based identification and chemical analysis of RNA in ribonucleoprotein complexes.

    Science.gov (United States)

    Taoka, Masato; Yamauchi, Yoshio; Nobe, Yuko; Masaki, Shunpei; Nakayama, Hiroshi; Ishikawa, Hideaki; Takahashi, Nobuhiro; Isobe, Toshiaki

    2009-11-01

    We describe here a mass spectrometry (MS)-based analytical platform of RNA, which combines direct nano-flow reversed-phase liquid chromatography (RPLC) on a spray tip column and a high-resolution LTQ-Orbitrap mass spectrometer. Operating RPLC under a very low flow rate with volatile solvents and MS in the negative mode, we could estimate highly accurate mass values sufficient to predict the nucleotide composition of a approximately 21-nucleotide small interfering RNA, detect post-transcriptional modifications in yeast tRNA, and perform collision-induced dissociation/tandem MS-based structural analysis of nucleolytic fragments of RNA at a sub-femtomole level. Importantly, the method allowed the identification and chemical analysis of small RNAs in ribonucleoprotein (RNP) complex, such as the pre-spliceosomal RNP complex, which was pulled down from cultured cells with a tagged protein cofactor as bait. We have recently developed a unique genome-oriented database search engine, Ariadne, which allows tandem MS-based identification of RNAs in biological samples. Thus, the method presented here has broad potential for automated analysis of RNA; it complements conventional molecular biology-based techniques and is particularly suited for simultaneous analysis of the composition, structure, interaction, and dynamics of RNA and protein components in various cellular RNP complexes.

  6. Mass

    International Nuclear Information System (INIS)

    Quigg, Chris

    2007-01-01

    In the classical physics we inherited from Isaac Newton, mass does not arise, it simply is. The mass of a classical object is the sum of the masses of its parts. Albert Einstein showed that the mass of a body is a measure of its energy content, inviting us to consider the origins of mass. The protons we accelerate at Fermilab are prime examples of Einsteinian matter: nearly all of their mass arises from stored energy. Missing mass led to the discovery of the noble gases, and a new form of missing mass leads us to the notion of dark matter. Starting with a brief guided tour of the meanings of mass, the colloquium will explore the multiple origins of mass. We will see how far we have come toward understanding mass, and survey the issues that guide our research today.

  7. Dissociative symptoms in kleptomania.

    Science.gov (United States)

    Grant, Jon E

    2004-02-01

    Many patients with kleptomania report an altered state of consciousness during acts of theft. The purpose of this investigation was to clarify a possible link between dissociation and kleptomania, a disabling disorder whose phenomenology remains understudied. 26 adult outpatients who met DSM-IV criteria for kleptoania were administered the Dissociative Experiences Scale and compared to 22 normal controls. The patients with kleptomania had scores that differed significantly from those reported by normal controls. There were no statistically significant differences by sex. Because kleptomania patients seeking treatment with medication may differ from others with kleptomania, further studies are needed.

  8. Online coupling of high-resolution chromatography with extreme UV photon activation tandem mass spectrometry: Application to the structural investigation of complex glycans by dissociative photoionization

    International Nuclear Information System (INIS)

    Ropartz, David; Giuliani, Alexandre; Fanuel, Mathieu; Hervé, Cécile; Czjzek, Mirjam; Rogniaux, Hélène

    2016-01-01

    The activation of ions by extreme-energy photons (XUV) produced by a synchrotron radiation beamline is a powerful method for characterizing complex glycans using tandem mass spectrometry (MS). As previously described, this activation method leads to rich fragmentation spectra with many structurally valuable cross-ring cleavages while maintaining labile modifications on the glycan structures. However, until now, the tandem MS event was too long to be compatible with liquid chromatography elution times. In this work, the duty cycle of the activation and detection of fragments was shortened, and the background signal on the spectra was drastically reduced. Both improvements allowed, for the first time, the successful coupling of a UHPLC system to XUV-activated tandem MS. The approach was used to characterize a complex mixture of oligo-porphyrans, which are a class of highly sulfated oligosaccharides, in a fully automated way. Due to an enhanced dynamic range and an increased sensitivity, some hypothetical structures of low abundance have been unequivocally confirmed in this study and others have been revised. Some previously undescribed species of oligo-porphyrans that exhibit lateral branching have been fully resolved. This work contributes to the scarce knowledge of the structure of porphyrans in red algae and pushes the current capacities of XUV-activation tandem MS by demonstrating the possibility of a direct coupling with UHPLC. This study will considerably broaden the applicability and practicality of this method in many fields of analytical biology. - Highlights: • For the first time, XUV photon activation tandem MS was coupled to UHPLC. • The approach was used to characterize a complex mixture of biomolecules. • The MSMS duty cycle was compatible with elution times of UHPLC without compromised. • Minor species were characterized with an enhanced sensitivity and dynamic range. • These results broaden the application of the technique in many field of

  9. Online coupling of high-resolution chromatography with extreme UV photon activation tandem mass spectrometry: Application to the structural investigation of complex glycans by dissociative photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Ropartz, David, E-mail: David.Ropartz@nantes.inra.fr [INRA, UR1268 Biopolymers Interactions Assemblies F-44316 Nantes (France); Giuliani, Alexandre [Synchrotron SOLEIL, L' Orme des Merisiers, F-91190 Gif-sur-Yvette (France); UAR 1008 CEPIA, INRA, F-44316 Nantes (France); Fanuel, Mathieu [INRA, UR1268 Biopolymers Interactions Assemblies F-44316 Nantes (France); Hervé, Cécile; Czjzek, Mirjam [Sorbonne Universités, Université Pierre et Marie Curie, Paris VI, CNRS, Integrative Biology of Marine Models, UMR 8227, Station Biologique, Place George Teissier, F29688 Roscoff Cedex (France); Rogniaux, Hélène [INRA, UR1268 Biopolymers Interactions Assemblies F-44316 Nantes (France)

    2016-08-24

    The activation of ions by extreme-energy photons (XUV) produced by a synchrotron radiation beamline is a powerful method for characterizing complex glycans using tandem mass spectrometry (MS). As previously described, this activation method leads to rich fragmentation spectra with many structurally valuable cross-ring cleavages while maintaining labile modifications on the glycan structures. However, until now, the tandem MS event was too long to be compatible with liquid chromatography elution times. In this work, the duty cycle of the activation and detection of fragments was shortened, and the background signal on the spectra was drastically reduced. Both improvements allowed, for the first time, the successful coupling of a UHPLC system to XUV-activated tandem MS. The approach was used to characterize a complex mixture of oligo-porphyrans, which are a class of highly sulfated oligosaccharides, in a fully automated way. Due to an enhanced dynamic range and an increased sensitivity, some hypothetical structures of low abundance have been unequivocally confirmed in this study and others have been revised. Some previously undescribed species of oligo-porphyrans that exhibit lateral branching have been fully resolved. This work contributes to the scarce knowledge of the structure of porphyrans in red algae and pushes the current capacities of XUV-activation tandem MS by demonstrating the possibility of a direct coupling with UHPLC. This study will considerably broaden the applicability and practicality of this method in many fields of analytical biology. - Highlights: • For the first time, XUV photon activation tandem MS was coupled to UHPLC. • The approach was used to characterize a complex mixture of biomolecules. • The MSMS duty cycle was compatible with elution times of UHPLC without compromised. • Minor species were characterized with an enhanced sensitivity and dynamic range. • These results broaden the application of the technique in many field of

  10. Collision-induced Raman scattering and the peculiar case of neon: Anisotropic spectrum, anisotropy, and the inverse scattering problem

    International Nuclear Information System (INIS)

    Dixneuf, Sophie; Rachet, Florent; Chrysos, Michael

    2015-01-01

    Owing in part to the p orbitals of its filled L shell, neon has repeatedly come on stage for its peculiar properties. In the context of collision-induced Raman spectroscopy, in particular, we have shown, in a brief report published a few years ago [M. Chrysos et al., Phys. Rev. A 80, 054701 (2009)], that the room-temperature anisotropic Raman lineshape of Ne–Ne exhibits, in the far wing of the spectrum, a peculiar structure with an aspect other than a smooth wing (on a logarithmic plot) which contrasts with any of the existing studies, and whose explanation lies in the distinct way in which overlap and exchange interactions interfere with the classical electrostatic ones in making the polarizability anisotropy, α ∥ − α ⊥ . Here, we delve deeper into that study by reporting data for that spectrum up to 450 cm −1 and for even- and odd-order spectral moments up to M 6 , as well as quantum lineshapes, generated from SCF, CCSD, and CCSD(T) models for α ∥ − α ⊥ , which are critically compared with the experiment. On account of the knowledge of the spectrum over the augmented frequency domain, we show how the inverse scattering problem can be tackled both effectively and economically, and we report an analytic function for the anisotropy whose quantum lineshape faithfully reproduces our observations

  11. Computational analyses of spectral trees from electrospray multi-stage mass spectrometry to aid metabolite identification.

    Science.gov (United States)

    Cao, Mingshu; Fraser, Karl; Rasmussen, Susanne

    2013-10-31

    Mass spectrometry coupled with chromatography has become the major technical platform in metabolomics. Aided by peak detection algorithms, the detected signals are characterized by mass-over-charge ratio (m/z) and retention time. Chemical identities often remain elusive for the majority of the signals. Multi-stage mass spectrometry based on electrospray ionization (ESI) allows collision-induced dissociation (CID) fragmentation of selected precursor ions. These fragment ions can assist in structural inference for metabolites of low molecular weight. Computational investigations of fragmentation spectra have increasingly received attention in metabolomics and various public databases house such data. We have developed an R package "iontree" that can capture, store and analyze MS2 and MS3 mass spectral data from high throughput metabolomics experiments. The package includes functions for ion tree construction, an algorithm (distMS2) for MS2 spectral comparison, and tools for building platform-independent ion tree (MS2/MS3) libraries. We have demonstrated the utilization of the package for the systematic analysis and annotation of fragmentation spectra collected in various metabolomics platforms, including direct infusion mass spectrometry, and liquid chromatography coupled with either low resolution or high resolution mass spectrometry. Assisted by the developed computational tools, we have demonstrated that spectral trees can provide informative evidence complementary to retention time and accurate mass to aid with annotating unknown peaks. These experimental spectral trees once subjected to a quality control process, can be used for querying public MS2 databases or de novo interpretation. The putatively annotated spectral trees can be readily incorporated into reference libraries for routine identification of metabolites.

  12. Dissociation of acetaldehyde in intense laser field: Coulomb explosion or field-assisted dissociation?

    Science.gov (United States)

    Elshakre, Mohamed E.; Gao, Lirong; Tang, Xiaoping; Wang, Sufan; Shu, Yafei; Kong, Fanao

    2003-09-01

    Dissociation of acetaldehyde in moderate strong laser field of 1013-1014W/cm2 was investigated. Singly charged parent ion CH3CHO+ and fragmental ions CH3+, CHO+, C2H4+, O+, CH2CHO+, and H+ were produced by 800 nm laser of 100 fs pulse duration and recorded by time-of-flight mass spectrometer. The CH3+ fragment further dissociated to CH2+, CH+, and C+ ions at higher intensity. Ab initio calculated results show that the singly-, doubly-, and triply charged parent ions are stable. So, the dissociation mechanism was not due to Coulomb explosion of multicharged ion. A field-assisted dissociation (FAD) theory, which assumes that only one bond undergoes dissociation while the rest of the molecular geometry stays unchanged, was employed to treat the dissociation dynamics. Accordingly, the dressed potential energy surfaces of the ground state for the parent and the fragment ions were calculated. Corresponding quasiclassical trajectory calculations show that the bond ruptures take place in the order of C-C, C-O, and C-H, agreeing with the observation. The observed angular dependence and charge distribution of the product ions can also be interpreted by the FAD theory.

  13. Dissociation and psychosis in dissociative identity disorder and schizophrenia.

    Science.gov (United States)

    Laddis, Andreas; Dell, Paul F

    2012-01-01

    Dissociative symptoms, first-rank symptoms of schizophrenia, and delusions were assessed in 40 schizophrenia patients and 40 dissociative identity disorder (DID) patients with the Multidimensional Inventory of Dissociation (MID). Schizophrenia patients were diagnosed with the Structured Clinical Interview for the DSM-IV Axis I Disorders; DID patients were diagnosed with the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised. DID patients obtained significantly (a) higher dissociation scores; (b) higher passive-influence scores (first-rank symptoms); and (c) higher scores on scales that measure child voices, angry voices, persecutory voices, voices arguing, and voices commenting. Schizophrenia patients obtained significantly higher delusion scores than did DID patients. What is odd is that the dissociation scores of schizophrenia patients were unrelated to their reports of childhood maltreatment. Multiple regression analyses indicated that 81% of the variance in DID patients' dissociation scores was predicted by the MID's Ego-Alien Experiences Scale, whereas 92% of the variance in schizophrenia patients' dissociation scores was predicted by the MID's Voices Scale. We propose that schizophrenia patients' responses to the MID do not index the same pathology as do the responses of DID patients. We argue that neither phenomenological definitions of dissociation nor the current generation of dissociation instruments (which are uniformly phenomenological in nature) can distinguish between the dissociative phenomena of DID and what we suspect are just the dissociation-like phenomena of schizophrenia.

  14. Collision-induced spectroscopy with long-range intermolecular interactions: A diagrammatic representation and the invariant form of the induced properties

    International Nuclear Information System (INIS)

    Kouzov, A. P.; Chrysos, M.; Rachet, F.; Egorova, N. I.

    2006-01-01

    Collision-induced properties of two interacting molecules a and b are derived by means of a general diagrammatic method involving M molecule-molecule and N photon-molecule couplings. The method is an extension of previous graphical treatments of nonlinear optics because it exhaustively determines interaction-induced polarization mechanisms in a trustworthy and handy fashion. Here we focus on long-range intermolecular interactions. Retardation effects are neglected. A fully quantum-mechanical treatment of the molecules is made whereas second quantization for the electromagnetic field, in the nonrelativistic approximation, is implicitly applied. The collision-induced absorption, Raman, and hyper-Raman processes are viewed and studied, through guiding examples, as specific cases N=1, 2, and 3, respectively. In Raman (N=2), the standard first-order (M=1) dipole-induced dipole term of the incremental polarizability, Δα, is the result of a coupling of the two photons with distinct molecules, a and b, which perturb each other via a dipole-dipole mechanism. Rather, when the two photons interact with the same molecule, a or b, the (N=2, M=1) graphs predict the occurrence of a nonlinear polarization mechanism. The latter is expected to contribute substantially to the collision-induced Raman bands by certain molecular gases

  15. Dissociative Identity Disorder

    Science.gov (United States)

    Schmidt, Tom

    2007-01-01

    Few psychological disorders in the Diagnostic Statistical Manual have generated as much controversy as Dissociative Identity Disorder (DID). For the past 35 years diagnoses of DID, previously referred to as Multiple Personality Disorder (MPD), have increased exponentially, causing various psychological researchers and clinicians to question the…

  16. Neurophysiological correlates of dissociative symptoms

    NARCIS (Netherlands)

    Kruijs, van der S.J.M.; Bodde, N.M.G; Carrette, E.C.B.; Lazeron, R.H.C; Vonck, K.E.J.; Boon, P.A.J.M.; Langereis, G.R.; Cluitmans, P.J.M.; Feijs, L.M.G.; Hofman, P.A.M.; Backes, W.H.; Jansen, J.F.A.; Aldenkamp, A.P.

    2014-01-01

    Objective: Dissociation is a mental process with psychological and somatoform manifestations, which is closely related to hypnotic suggestibility and essentially shows the ability to obtain distance from reality. An increased tendency to dissociate is a frequently reported characteristic of patients

  17. A survey of useful salt additives in matrix-assisted laser desorption/ionization mass spectrometry and tandem mass spectrometry of lipids: introducing nitrates for improved analysis.

    Science.gov (United States)

    Griffiths, Rian L; Bunch, Josephine

    2012-07-15

    Matrix-assisted laser desorption/ionization (MALDI) is a powerful technique for the direct analysis of lipids in complex mixtures and thin tissue sections, making it an extremely attractive method for profiling lipids in health and disease. Lipids are readily detected as [M+H](+), [M+Na](+) and [M+K](+) ions in positive ion MALDI mass spectrometry (MS) experiments. This not only decreases sensitivity, but can also lead to overlapping m/z values of the various adducts of different lipids. Additives can be used to promote formation of a particular adduct, improving sensitivity, reducing spectral complexity and enhancing structural characterization in collision-induced dissociation (CID) experiments. Li(+), Na(+), K(+), Cs(+) and NH(4)(+) cations were considered as a range of salt types (acetates, chlorides and nitrates) incorporated into DHB matrix solutions at concentrations between 5 and 80 mM. The study was extended to evaluate the effect of these additives on CID experiments of a lipid standard, after optimization of collision energy parameters. Experiments were performed on a hybrid quadrupole time-of-flight (QqTOF) instrument. The systematic evaluation of new and existing additives in MALDI-MS and MS/MS of lipids demonstrated the importance of additive cation and anion choice and concentration for tailoring spectral results. The recommended choice of additive depends on the desired outcomes of the experiment to be performed (MS or MS/MS). Nitrates are found to be particularly useful additives for lipid analysis. Copyright © 2012 John Wiley & Sons, Ltd.

  18. Three dimensions of dissociative amnesia.

    Science.gov (United States)

    Dell, Paul F

    2013-01-01

    Principal axis factor analysis with promax rotation extracted 3 factors from the 42 memory and amnesia items of the Multidimensional Inventory of Dissociation (MID) database (N = 2,569): Discovering Dissociated Actions, Lapses of Recent Memory and Skills, and Gaps in Remote Memory. The 3 factors' shared variance ranged from 36% to 64%. Construed as scales, the 3 factor scales had Cronbach's alpha coefficients of .96, .94, and .93, respectively. The scales correlated strongly with mean Dissociative Experiences Scale scores, mean MID scores, and total scores on the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised (SCID-D-R). What is interesting is that the 3 amnesia factors exhibited a range of correlations with SCID-D-R Amnesia scores (.52, .63, and .70, respectively), suggesting that the SCID-D-R Amnesia score emphasizes gaps in remote memory over amnesias related to dissociative identity disorder. The 3 amnesia factor scales exhibited a clinically meaningful pattern of significant differences among dissociative identity disorder, dissociative disorder not otherwise specified-1, dissociative amnesia, depersonalization disorder, and nonclinical participants. The 3 amnesia factors may have greater clinical utility for frontline clinicians than (a) amnesia as discussed in the context of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, nosology of the dissociative disorders or (b) P. Janet's (1893/1977 ) 4-fold classification of dissociative amnesia. The author recommends systematic study of the phenomenological differences within specific dissociative symptoms and their differential relationship to specific dissociative disorders.

  19. Symmetry Breakdown in Ground State Dissociation of HD+

    International Nuclear Information System (INIS)

    Ben-Itzhak, I.; Wells, E.; Carnes, K. D.; Krishnamurthi, Vidhya; Weaver, O. L.; Esry, B. D.

    2000-01-01

    Experimental studies of the dissociation of the electronic ground state of HD + following ionization of HD by fast proton impact indicate that the H + +D 1s dissociation channel is more likely than the H1s+D + dissociation channel by about 7% . This isotopic symmetry breakdown is due to the finite nuclear mass correction to the Born-Oppenheimer approximation which makes the 1sσ state 3.7 meV lower than the 2pσ state at the dissociation limit. The measured fractions of the two dissociation channels are in agreement with coupled-channels calculations of 1sσ to 2pσ transitions. (c) 2000 The American Physical Society

  20. Simple setup for gas-phase H/D exchange mass spectrometry coupled to electron transfer dissociation and ion mobility for analysis of polypeptide structure on a liquid chromatographic time scale.

    Science.gov (United States)

    Mistarz, Ulrik H; Brown, Jeffery M; Haselmann, Kim F; Rand, Kasper D

    2014-12-02

    Gas-phase hydrogen/deuterium exchange (HDX) is a fast and sensitive, yet unharnessed analytical approach for providing information on the structural properties of biomolecules, in a complementary manner to mass analysis. Here, we describe a simple setup for ND3-mediated millisecond gas-phase HDX inside a mass spectrometer immediately after ESI (gas-phase HDX-MS) and show utility for studying the primary and higher-order structure of peptides and proteins. HDX was achieved by passing N2-gas through a container filled with aqueous deuterated ammonia reagent (ND3/D2O) and admitting the saturated gas immediately upstream or downstream of the primary skimmer cone. The approach was implemented on three commercially available mass spectrometers and required no or minor fully reversible reconfiguration of gas-inlets of the ion source. Results from gas-phase HDX-MS of peptides using the aqueous ND3/D2O as HDX reagent indicate that labeling is facilitated exclusively through gaseous ND3, yielding similar results to the infusion of purified ND3-gas, while circumventing the complications associated with the use of hazardous purified gases. Comparison of the solution-phase- and gas-phase deuterium uptake of Leu-Enkephalin and Glu-Fibrinopeptide B, confirmed that this gas-phase HDX-MS approach allows for labeling of sites (heteroatom-bound non-amide hydrogens located on side-chains, N-terminus and C-terminus) not accessed by classical solution-phase HDX-MS. The simple setup is compatible with liquid chromatography and a chip-based automated nanoESI interface, allowing for online gas-phase HDX-MS analysis of peptides and proteins separated on a liquid chromatographic time scale at increased throughput. Furthermore, online gas-phase HDX-MS could be performed in tandem with ion mobility separation or electron transfer dissociation, thus enabling multiple orthogonal analyses of the structural properties of peptides and proteins in a single automated LC-MS workflow.

  1. Desorption electrospray ionisation mass spectrometry: A rapid screening tool for veterinary drug preparations and forensic samples from hormone crime investigations

    International Nuclear Information System (INIS)

    Nielen, M.W.F.; Hooijerink, H.; Claassen, F.C.; Engelen, M.C. van; Beek, T.A. van

    2009-01-01

    Hormone and veterinary drug screening and forensics can benefit from the recent developments in desorption electrospray ionisation (DESI) mass spectrometry (MS). In this work the feasibility of DESI application has been studied. Using a linear ion trap or quadrupole time-of-flight (TOF) MS instrument both full-scan and data-dependent collision-induced dissociation MS n spectra were acquired in seconds without sample preparation. Preliminary data are presented for the rapid screening of (pro)hormone supplement samples, an illegal steroid cocktail and forensic samples from veterinary drug investigations. The potential of this DESI approach is clearly demonstrated since compounds observed could be independently confirmed by liquid chromatography/TOFMS with accurate mass measurement, and/or proton nuclear magnetic resonance spectroscopy. Specific concerns related to false-positive and false-negative findings due to limitations in quantification and memory-effects are briefly discussed. It is envisaged that DESI will achieve a prominent role in hormone and veterinary drug analysis in the near future

  2. Desorption electrospray ionisation mass spectrometry: A rapid screening tool for veterinary drug preparations and forensic samples from hormone crime investigations

    Energy Technology Data Exchange (ETDEWEB)

    Nielen, M.W.F. [RIKILT Institute of Food Safety, P.O. Box 230, 6700 AE Wageningen (Netherlands); Wageningen University, Laboratory of Organic Chemistry, Dreijenplein 8, 6703 HB Wageningen (Netherlands)], E-mail: michel.nielen@wur.nl; Hooijerink, H. [RIKILT Institute of Food Safety, P.O. Box 230, 6700 AE Wageningen (Netherlands); Claassen, F.C. [Wageningen University, Laboratory of Organic Chemistry, Dreijenplein 8, 6703 HB Wageningen (Netherlands); Engelen, M.C. van [RIKILT Institute of Food Safety, P.O. Box 230, 6700 AE Wageningen (Netherlands); Beek, T.A. van [Wageningen University, Laboratory of Organic Chemistry, Dreijenplein 8, 6703 HB Wageningen (Netherlands)

    2009-04-01

    Hormone and veterinary drug screening and forensics can benefit from the recent developments in desorption electrospray ionisation (DESI) mass spectrometry (MS). In this work the feasibility of DESI application has been studied. Using a linear ion trap or quadrupole time-of-flight (TOF) MS instrument both full-scan and data-dependent collision-induced dissociation MS{sup n} spectra were acquired in seconds without sample preparation. Preliminary data are presented for the rapid screening of (pro)hormone supplement samples, an illegal steroid cocktail and forensic samples from veterinary drug investigations. The potential of this DESI approach is clearly demonstrated since compounds observed could be independently confirmed by liquid chromatography/TOFMS with accurate mass measurement, and/or proton nuclear magnetic resonance spectroscopy. Specific concerns related to false-positive and false-negative findings due to limitations in quantification and memory-effects are briefly discussed. It is envisaged that DESI will achieve a prominent role in hormone and veterinary drug analysis in the near future.

  3. Mass spectral analysis of N-oxides of Chemical Weapons Convention related aminoethanols under electrospray ionization conditions.

    Science.gov (United States)

    Sridhar, L; Karthikraj, R; Murty, M R V S; Raju, N Prasada; Vairamani, M; Prabhakar, S

    2011-02-28

    N,N'-Dialkylaminoethanols are the hydrolyzed products or precursors of chemical warfare agents such as V-agents and nitrogen mustards, and they are prone to undergo oxidation in environmental matrices or during decontamination processes. Consequently, screening of the oxidized products of aminoethanols in aqueous samples is an important task in the verification of chemical weapons convention-related chemicals. Here we report the successful characterization of the N-oxides of N,N'-dialkylaminoethanols, alkyl diethanolamines, and triethanolamine using positive ion electrospray ionization mass spectrometry. The collision-induced dissociation (CID) spectra of the [M+H](+) and [M+Na](+) ions show diagnostic product ions that enable the unambiguous identification of the studied N-oxides, including those of isomeric compounds. The proposed fragmentation pathways are supported by high-resolution mass spectrometry data and product/precursor ion spectra. The CID spectra of [M+H](+) ions included [MH-CH(4)O(2)](+) as the key product ion, in addition to a distinctive alkene loss that allowed us to recognize the alkyl group attached to the nitrogen. The [M+Na](+) ions show characteristic product ions due to the loss of groups (R) attached to nitrogen either as a radical (R) or as a molecule [R+H or (R-H)] after hydrogen migration. Copyright © 2011 John Wiley & Sons, Ltd.

  4. Use of ultra-high pressure liquid chromatography coupled to high resolution mass spectrometry for fast screening in high throughput doping control.

    Science.gov (United States)

    Musenga, Alessandro; Cowan, David A

    2013-05-03

    We describe a sensitive, comprehensive and fast screening method based on liquid chromatography-high resolution mass spectrometry for the detection of a large number of analytes in sports samples. UHPLC coupled to high resolution mass spectrometry with polarity switching capability is applied for the rapid screening of a large number of analytes in human urine samples. Full scan data are acquired alternating both positive and negative ionisation. Collision-induced dissociation with positive ionisation is also performed to produce fragment ions to improve selectivity for some analytes. Data are reviewed as extracted ion chromatograms based on narrow mass/charge windows (±5ppm). A simple sample preparation method was developed, using direct enzymatic hydrolysis of glucuronide conjugates, followed by solid phase extraction with mixed mode ion-exchange cartridges. Within a 10min run time (including re-equilibration) the method presented allows for the analysis of a large number of analytes from most of the classes in the World Anti-Doping Agency (WADA) Prohibited List, including anabolic agents, β2-agonists, hormone antagonists and modulators, diuretics, stimulants, narcotics, glucocorticoids and β-blockers, and does so while meeting the WADA sensitivity requirements. The high throughput of the method and the fast sample pre-treatment reduces analysis cost and increases productivity. The method presented has been used for the analysis of over 5000 samples in about one month and proved to be reliable. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Orientation dependence in collision induced electronic relaxation studied through van der Waals complexes with isomeric structures. Invited feature article

    International Nuclear Information System (INIS)

    Cheng, P.Y.; Lapierre, L.; Ju, S.S.; DeRose, P.; Dai, H.L.

    1994-01-01

    Weakly bound molecular complexes with more than one well-defined structures provide us with an unique opportunity to investigate dynamic processes induced by intermolecular interactions with specific orientations. The relative orientation of the two interacting molecules or atoms is defined by the complex structure. The effect of the orientation in the spin changing collisions glyoxal (S 1 ) + Ar → glyoxal (T 1 ) + Ar and acetylene (S 1 ) + Ar → acetylene (T) + Ar have been studied by measuring the intersystem crossing (ISC) rates of the glyoxal(S 1 ).Ar and acetylene(S 1 ).Ar complexes with different isomeric structures. Results show that there is a strong orientation dependence in the ISC of glyoxal(S 1 ) induced by interaction with the Ar atom: the Ar atom positioned in the molecular plane is much more effective than in the out-of-plane position in inducing the S 1 → T 1 transition of glyoxal. On the other hand, studies of acetylene(S 1 ).Ar complexes indicate that the Ar-induced ISC rates are nearly identical for the in-plane and out-of-plane positions. Orientation dependence in the collision induced vibrational relaxation process C 2 H 2 (S 1 , v i ) + Ar → C 2 H 2 (S 1 , v f i ) + Ar is also studied by measuring the vibrational predissociation rates of the acetylene(S 1 ).Ar complex isomers. The results indicate that collisions of C 2 H 2 (S 1 , v 3 = 3, 4) with Ar at two orthogonal orientations are equally effective in causing vibrational relaxation of C 2 H 2 . (orig.)

  6. Orbitrap mass spectrometry characterization of hybrid chondroitin/dermatan sulfate hexasaccharide domains expressed in brain.

    Science.gov (United States)

    Robu, Adrian C; Popescu, Laurentiu; Munteanu, Cristian V A; Seidler, Daniela G; Zamfir, Alina D

    2015-09-15

    In the central nervous system, chondroitin/dermatan sulfate (CS/DS) glycosaminoglycans (GAGs) modulate neurotrophic effects and glial cell maturation during brain development. Previous reports revealed that GAG composition could be responsible for CS/DS activities in brain. In this work, for the structural characterization of DS- and CS-rich domains in hybrid GAG chains extracted from neural tissue, we have developed an advanced approach based on high-resolution mass spectrometry (MS) using nanoelectrospray ionization Orbitrap in the negative ion mode. Our high-resolution MS and multistage MS approach was developed and applied to hexasaccharides obtained from 4- and 14-week-old mouse brains by GAG digestion with chondroitin B and in parallel with AC I lyase. The expression of DS- and CS-rich domains in the two tissues was assessed comparatively. The analyses indicated an age-related structural variability of the CS/DS motifs. The older brain was found to contain more structures and a higher sulfation of DS-rich regions, whereas the younger brain was found to be characterized by a higher sulfation of CS-rich regions. By multistage MS using collision-induced dissociation, we also demonstrated the incidence in mouse brain of an atypical [4,5-Δ-GlcAGalNAc(IdoAGalNAc)2], presenting a bisulfated CS disaccharide formed by 3-O-sulfate-4,5-Δ-GlcA and 6-O-sulfate-GalNAc moieties. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Food contaminant analysis at ultra-high mass resolution: application of hybrid linear ion trap - orbitrap mass spectrometry for the determination of the polyether toxins, azaspiracids, in shellfish.

    LENUS (Irish Health Repository)

    2010-10-30

    The biotoxins, azaspiracids (AZAs), from marine phytoplankton accumulate in shellfish and affect human health by causing severe gastrointestinal disturbance, diarrhea, nausea and vomiting. Specific and sensitive methods have been developed and validated for the determination of the most commonly occurring azaspiracid analogs. An LTQ Orbitrap mass spectrometer is a hybrid instrument that combines linear ion trap (LIT) mass spectrometry (MS) with high-resolution Fourier transform (FT) MS and this was exploited to perform simultaneous ultra-high-resolution full-scan MS analysis and collision-induced dissociation (CID) tandem mass spectrometry (MS\\/MS). Using the highest mass resolution setting (100,000 FWHM) in full-scan mode, the methodology was validated for the determination of six AZAs in mussel (Mytilus galloprovincialis) tissue extracts. Ultra-high mass resolution, together with a narrow mass tolerance window of ±2 mDa, dramatically improved detection sensitivity. In addition to employing chromatographic resolution to distinguish between the isomeric azaspiracid analogs, AZA1\\/AZA6 and AZA4\\/AZA5, higher energy collisionally induced dissociation (HCD) fragmentation on selected precursor ions were performed in parallel with full-scan FTMS. Using HCD MS\\/MS, most precursor and product ion masses were determined within 1 ppm of the theoretical m\\/z values throughout the mass spectral range and this enhanced the reliability of analyte identity.For the analysis of mussels (M. galloprovincialis), the method limit of quantitation (LOQ) was 0.010 µg\\/g using full-scan FTMS and this was comparable with the LOQ (0.007 µg\\/g) using CID MS\\/MS. The repeatability data were; intra-day RSD% (1.8-4.4%; n = 6) and inter-day RSD% (4.7-8.6%; n = 3). Application of these methods to the analysis of mussels (M. edulis) that were naturally contaminated with azaspiracids, using high-resolution full-scan Orbitrap MS and low-resolution CID MS\\/MS, produced

  8. Dissociative electron attachment to the radiosensitizing chemotherapeutic agent hydroxyurea

    Science.gov (United States)

    Huber, S. E.; Śmiałek, M. A.; Tanzer, K.; Denifl, S.

    2016-06-01

    Dissociative electron attachment to hydroxyurea was studied in the gas phase for electron energies ranging from zero to 9 eV in order to probe its radiosensitizing capabilities. The experiments were carried out using a hemispherical electron monochromator coupled with a quadrupole mass spectrometer. Diversified fragmentation of hydroxyurea was observed upon low energy electron attachment and here we highlight the major dissociation channels. Moreover, thermodynamic thresholds for various fragmentation reactions are reported to support the discussion of the experimental findings. The dominant dissociation channel, which was observed over a broad range of energies, is associated with formation of NCO-, water, and the amidogen (NH2) radical. The second and third most dominant dissociation channels are associated with formation of NCNH- and NHCONH2-, respectively, which are both directly related to formation of the highly reactive hydroxyl radical. Other ions observed with significant abundance in the mass spectra were NH2-/O-, OH-, CN-, HNOH-, NCONH2-, and ONHCONH2-.

  9. Identification of membrane proteins by tandem mass spectrometry of protein ions

    Science.gov (United States)

    Carroll, Joe; Altman, Matthew C.; Fearnley, Ian M.; Walker, John E.

    2007-01-01

    The most common way of identifying proteins in proteomic analyses is to use short segments of sequence (“tags”) determined by mass spectrometric analysis of proteolytic fragments. The approach is effective with globular proteins and with membrane proteins with significant polar segments between membrane-spanning α-helices, but it is ineffective with other hydrophobic proteins where protease cleavage sites are either infrequent or absent. By developing methods to purify hydrophobic proteins in organic solvents and by fragmenting ions of these proteins by collision induced dissociation with argon, we have shown that partial sequences of many membrane proteins can be deduced easily by manual inspection. The spectra from small proteolipids (1–4 transmembrane α-helices) are dominated usually by fragment ions arising from internal amide cleavages, from which internal sequences can be obtained, whereas the spectra from larger membrane proteins (5–18 transmembrane α-helices) often contain fragment ions from N- and/or C-terminal parts yielding sequences in those regions. With these techniques, we have, for example, identified an abundant protein of unknown function from inner membranes of mitochondria that to our knowledge has escaped detection in proteomic studies, and we have produced sequences from 10 of 13 proteins encoded in mitochondrial DNA. They include the ND6 subunit of complex I, the last of its 45 subunits to be analyzed. The procedures have the potential to be developed further, for example by using newly introduced methods for protein ion dissociation to induce fragmentation of internal regions of large membrane proteins, which may remain partially folded in the gas phase. PMID:17720804

  10. The mechanisms of the hadron-nucleus collision processes and of the hadron-nucleus collision induced nuclear reactions - in the light of experimental data

    International Nuclear Information System (INIS)

    Strugalski, Z.; Strugalska-Gola, E.

    1997-01-01

    The mechanisms of the hadron-nucleus collision processes and of the hadron-nucleus collision induced nuclear reactions are described - as experimentally based. The target nuclei are damaged definitely and locally in the collisions and the configurations of the nucleons in them became instable. The configuration must transit into stable stages of the nuclear transition reaction products. The difference between the initial internal energy of the unstable residual nucleus and the total final energy of the stable products of the nuclear transition reaction may be released in some cases

  11. Effect of temperature and solvent composition on acid dissociation equilibria, I: Sequenced sspKa determination of compounds commonly used as buffers in high performance liquid chromatography coupled to mass spectroscopy detection

    International Nuclear Information System (INIS)

    Padró, Juan M.; Acquaviva, Agustín; Tascon, Marcos; Gagliardi, Leonardo G.; Castells, Cecilia B.

    2012-01-01

    Highlights: ► We developed a rapid potentiometric method for sequential pK a determinations. ► We measured pK a of buffers from 0 to 90% (v/v) acetonitrile/water and from 20 to 60 °C. ► Sequences of 42 pK a -data spanned over a wide solvent composition range needed 2 h. ► We measured pK a of formic acid and triethylamine/HCl in up to 90% (v/v) acetonitrile. ► The high-throughput method was applied to obtain pK a of two common buffers in LC/MS. - Abstract: A new automated and rapid potentiometric method for determining the effect of organic-solvent composition on pK a has been developed. It is based on the measurements of pH values of buffer solutions of variable solvent compositions using a combined glass electrode. Additions of small volumes of one precisely thermostated solution into another, both containing exactly the same analytical concentrations of the buffer components, can produce continuous changes in the solvent composition. Two sequences of potential measurements, one of increasing and the other of decreasing solvent content, are sufficient to obtain the pK a values of the acidic compound within the complete solvent-composition range in about 2 h. The experimental design, procedures, and calculations needed to convert the measured pH into the thermodynamic pK a values are thoroughly discussed. This rapid and automated method allows the systematic study of the effect of solvent compositions and temperatures on the pK a . It has been applied to study the dissociation constants of two monoprotic acids: formic acid and triethylamine:HCl in acetonitrile/water mixtures within the range from 0 to 90% (v/v) at temperatures between 20 °C and 60 °C. These volatile compounds are frequently used to control the pH of the mobile phase in HPLC, especially in methods coupled to mass-spectrometry detection. The obtained pK a values are in excellent agreement with those previously reported. The results were fitted to empirical functions between pK a and

  12. Effect of temperature and solvent composition on acid dissociation equilibria, I: Sequenced {sup s}{sub s}pK{sub a} determination of compounds commonly used as buffers in high performance liquid chromatography coupled to mass spectroscopy detection

    Energy Technology Data Exchange (ETDEWEB)

    Padro, Juan M.; Acquaviva, Agustin; Tascon, Marcos [Laboratorio de Separaciones Analiticas, Division Quimica Analitica, Universidad Nacional de La Plata y CIDEPINT, 47 y 115, (1900) La Plata (Argentina); Gagliardi, Leonardo G., E-mail: leogagliardi@quimica.unlp.edu.ar [Laboratorio de Separaciones Analiticas, Division Quimica Analitica, Universidad Nacional de La Plata y CIDEPINT, 47 y 115, (1900) La Plata (Argentina); Castells, Cecilia B., E-mail: castells@isis.unlp.edu.ar [Laboratorio de Separaciones Analiticas, Division Quimica Analitica, Universidad Nacional de La Plata y CIDEPINT, 47 y 115, (1900) La Plata (Argentina)

    2012-05-06

    Highlights: Black-Right-Pointing-Pointer We developed a rapid potentiometric method for sequential pK{sub a} determinations. Black-Right-Pointing-Pointer We measured pK{sub a} of buffers from 0 to 90% (v/v) acetonitrile/water and from 20 to 60 Degree-Sign C. Black-Right-Pointing-Pointer Sequences of 42 pK{sub a}-data spanned over a wide solvent composition range needed 2 h. Black-Right-Pointing-Pointer We measured pK{sub a} of formic acid and triethylamine/HCl in up to 90% (v/v) acetonitrile. Black-Right-Pointing-Pointer The high-throughput method was applied to obtain pK{sub a} of two common buffers in LC/MS. - Abstract: A new automated and rapid potentiometric method for determining the effect of organic-solvent composition on pK{sub a} has been developed. It is based on the measurements of pH values of buffer solutions of variable solvent compositions using a combined glass electrode. Additions of small volumes of one precisely thermostated solution into another, both containing exactly the same analytical concentrations of the buffer components, can produce continuous changes in the solvent composition. Two sequences of potential measurements, one of increasing and the other of decreasing solvent content, are sufficient to obtain the pK{sub a} values of the acidic compound within the complete solvent-composition range in about 2 h. The experimental design, procedures, and calculations needed to convert the measured pH into the thermodynamic pK{sub a} values are thoroughly discussed. This rapid and automated method allows the systematic study of the effect of solvent compositions and temperatures on the pK{sub a}. It has been applied to study the dissociation constants of two monoprotic acids: formic acid and triethylamine:HCl in acetonitrile/water mixtures within the range from 0 to 90% (v/v) at temperatures between 20 Degree-Sign C and 60 Degree-Sign C. These volatile compounds are frequently used to control the pH of the mobile phase in HPLC, especially in

  13. [Dissociative disorders and affective disorders].

    Science.gov (United States)

    Montant, J; Adida, M; Belzeaux, R; Cermolacce, M; Pringuey, D; Da Fonseca, D; Azorin, J-M

    2014-12-01

    The phenomenology of dissociative disorders may be complex and sometimes confusing. We describe here two cases who were initially misdiagnosed. The first case concerned a 61 year-old woman, who was initially diagnosed as an isolated dissociative fugue and was actually suffering from severe major depressive episode. The second case concerned a 55 year-old man, who was suffering from type I bipolar disorder and polyvascular disease, and was initially diagnosed as dissociative fugue in a mooddestabilization context, while it was finally a stroke. Yet dissociative disorders as affective disorder comorbidity are relatively unknown. We made a review on this topic. Dissociative disorders are often studied through psycho-trauma issues. Litterature is rare on affective illness comorbid with dissociative disorders, but highlight the link between bipolar and dissociative disorders. The later comorbidity often refers to an early onset subtype with also comorbid panic and depersonalization-derealization disorder. Besides, unipolar patients suffering from dissociative symptoms have more often cyclothymic affective temperament. Despite the limits of such studies dissociative symptoms-BD association seems to correspond to a clinical reality and further works on this topic may be warranted. Copyright © 2014 L’Encéphale. Published by Elsevier Masson SAS.. All rights reserved.

  14. Multiphoton dissociation of polyatomic molecules

    International Nuclear Information System (INIS)

    Schulz, P.A.

    1979-10-01

    The dynamics of infrared multiphoton excitation and dissociation of SF 6 was investigated under collision free conditions by a crossed laser-molecular beam method. In order to understand the excitation mechanism and to elucidate the requirements of laser intensity and energy fluence, a series of experiments were carried out to measure the dissociation yield dependences on energy fluence, vibrational temperature of SF 6 , the pulse duration of the CO 2 laser and the frequency in both one and two laser experiments. Translational energy distributions of the SF 5 dissociation product measured by time of flight and angular distributions and the dissociation lifetime of excited SF 6 as inferred from the observation of secondary dissociation of SF 5 into SF 4 and F during the laser pulse suggest that the dynamics of dissociation of excited molecules is dominated by complete energy randomization and rapid intramolecular energy transfer on a nanosecond timescale, and can be adequately described by RRKM theory. An improved phenomenological model including the initial intensity dependent excitation, a rate equation describing the absorption and stimulated emission of single photons, and the unimolecular dissociation of excited molecules is constructed based on available experimental results. The model shows that the energy fluence of the laser determines the excitation of molecules in the quasi-continuum and the excess energy with which molecules dissociate after the laser pulse. The role played by the laser intensity in multiphoton dissociation is more significant than just that of overcoming the intensity dependent absorption in the lowest levels. 63 references

  15. Strong-field dissociation dynamics

    International Nuclear Information System (INIS)

    DiMauro, L.F.; Yang, Baorui.

    1993-01-01

    The strong-field dissociation behavior of diatomic molecules is examined under two distinctive physical scenarios. In the first scenario, the dissociation of the isolated hydrogen and deuterium molecular ions is discussed. The dynamics of above-threshold dissociation (ATD) are investigated over a wide range of green and infrared intensities and compared to a dressed-state model. The second situation arises when strong-field neutral dissociation is followed by ionization of the atomic fragments. The study results in a direct measure of the atomic fragment's ac-Stark shift by observing the intensity-dependent shifts in the electron or nuclear fragment kinetic energy. 8 figs., 14 refs

  16. The Study of Titanium and Zirconium Ions in Water by MPT-LTQ Mass Spectrometry in Negative Mode.

    Science.gov (United States)

    Yang, Junqing; Zheng, Mei; Liu, Qiuju; Yang, Meiling Zhu Chushan; Zhang, Yan; Zhu, Zhiqiang

    2017-09-26

    Microwave plasma torches (MPTs) can be used as simple and low power-consumption ambient ion sources. When MPT-mass spectrometry (MPT-MS) is applied in the detection of some metal elements, the metallic ions exhibit some novel features which are significantly different with those obtained by the traditional inductively coupled plasma (ICP)-mass spectrometry (ICP-MS) and may be helpful for metal element analysis. As the representative elements of group IVA, titanium and zirconium are both of importance and value in modern industry, and they have impacts on human health. Here, we first provide a study on the complex anions of titanium and zirconium in water by using the MPT as ion source and a linear ion trap mass spectrometer (LTQ-MS). These complex anions were produced in the plasma flame by an aqueous solution flowing through the central tube of the MPT, and were introduced into the inlet of the mass spectrometry working in negative ion mode to get the feature mass spectrometric signals. Moreover, the feature fragment patterns of these ions in multi-step collision- induced dissociation processes have been explained. Under the optimized conditions, the limit of detection (LOD) using the MS² (the second tandem mass spectrometry) procedure was estimated to be at the level of 10μg/L for titanium and 20 μg/L for zirconium with linear dynamics ranges that cover at least two orders of magnitude, i.e., between 0-500 μg/L and 20-200 μg/L, respectively. These experimental data demonstrated that the MPT-MS is a promising and useful tool in field analysis of titanium and zirconium ions in water, and can be applied in many fields, such as environmental control, hydrogeology, and water quality inspection. In addition, MPT-MS could also be used as a supplement of ICP-MS for the rapid and on-site analysis of metal ions.

  17. Liquid extraction surface analysis (LESA) of food surfaces employing chip-based nano-electrospray mass spectrometry.

    Science.gov (United States)

    Eikel, Daniel; Henion, Jack

    2011-08-30

    An automated surface-sampling technique called liquid extraction surface analysis (LESA), coupled with infusion nano-electrospray high-resolution mass spectrometry and tandem mass spectrometry (MS/MS), is described and applied to the qualitative determination of surface chemical residues resulting from the artificial spraying of selected fresh fruits and vegetables with representative pesticides. Each of the targeted pesticides was readily detected with both high-resolution and full-scan collision-induced dissociation (CID) mass spectra. In the case of simazine and sevin, a mass resolution of 100,000 was insufficient to distinguish the isobaric protonated molecules for these compounds. When the surface of a spinach leaf was analyzed by LESA, trace levels of diazinon were readily detected on the spinach purchased directly from a supermarket before they were sprayed with the five-pesticide mixture. A 30 s rinse under hot running tap water appeared to quantitatively remove all remaining residues of this pesticide. Diazinon was readily detected by LESA analysis on the skin of the artificially sprayed spinach. Finally, incurred pyrimethanil at a level of 169 ppb in a batch slurry of homogenized apples was analyzed by LESA and this pesticide was readily detected by both high-resolution mass spectrometry and full-scan CID mass spectrometry, thus showing that pesticides may also be detected in whole fruit homogenized samples. This report shows that representative pesticides on fruit and vegetable surfaces present at levels 20-fold below generally allowed EPA tolerance levels are readily detected and confirmed by the title technologies making LESA-MS as interesting screening method for food safety purposes. Copyright © 2011 John Wiley & Sons, Ltd.

  18. Top-Down and Bottom-Up Identification of Proteins by Liquid Extraction Surface Analysis Mass Spectrometry of Healthy and Diseased Human Liver Tissue

    Science.gov (United States)

    Sarsby, Joscelyn; Martin, Nicholas J.; Lalor, Patricia F.; Bunch, Josephine; Cooper, Helen J.

    2014-09-01

    Liquid extraction surface analysis mass spectrometry (LESA MS) has the potential to become a useful tool in the spatially-resolved profiling of proteins in substrates. Here, the approach has been applied to the analysis of thin tissue sections from human liver. The aim was to determine whether LESA MS was a suitable approach for the detection of protein biomarkers of nonalcoholic liver disease (nonalcoholic steatohepatitis, NASH), with a view to the eventual development of LESA MS for imaging NASH pathology. Two approaches were considered. In the first, endogenous proteins were extracted from liver tissue sections by LESA, subjected to automated trypsin digestion, and the resulting peptide mixture was analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) (bottom-up approach). In the second (top-down approach), endogenous proteins were extracted by LESA, and analyzed intact. Selected protein ions were subjected to collision-induced dissociation (CID) and/or electron transfer dissociation (ETD) mass spectrometry. The bottom-up approach resulted in the identification of over 500 proteins; however identification of key protein biomarkers, liver fatty acid binding protein (FABP1), and its variant (Thr→Ala, position 94), was unreliable and irreproducible. Top-down LESA MS analysis of healthy and diseased liver tissue revealed peaks corresponding to multiple (~15-25) proteins. MS/MS of four of these proteins identified them as FABP1, its variant, α-hemoglobin, and 10 kDa heat shock protein. The reliable identification of FABP1 and its variant by top-down LESA MS suggests that the approach may be suitable for imaging NASH pathology in sections from liver biopsies.

  19. Low Mass MS/MS Fragments of Protonated Amino Acids Used for Distinction of Their 13C- Isotopomers in Metabolic Studies

    Science.gov (United States)

    Ma, Xin; Dagan, Shai; Somogyi, Árpád; Wysocki, Vicki H.; Scaraffia, Patricia Y.

    2013-04-01

    Glu, Gln, Pro, and Ala are the main amino acids involved in ammonia detoxification in mosquitoes. In order to develop a tandem mass spectrometry method (MS2) to monitor each carbon of the above isotopically-labeled 13C-amino acids for metabolic studies, the compositions and origins of atoms in fragments of the protonated amino acid should be first elucidated. Thus, various electrospray (ESI)-based MS2 tools were employed to study the fragmentation of these unlabeled and isotopically-labeled amino acids and better understand their dissociation pathways. A broad range of fragments, including previously-undescribed low m/z fragments was revealed. The formulae of the fragments (from m/z 130 down to m/z 27) were confirmed by their accurate masses. The structures and conformations of the larger fragments of Glu were also explored by ion mobility mass spectrometry (IM-MS) and gas-phase hydrogen/deuterium exchange (HDX) experiments. It was found that some low m/z fragments ( m/z 27-30) are common to Glu, Gln, Pro, and Ala. The origins of carbons in these small fragments are discussed and additional collision induced dissociation (CID) MS2 fragmentation pathways are proposed for them. It was also found that small fragments (≤ m/z 84) of protonated, methylated Glu, and methylated Gln are the same as those of the underivatized Glu and Gln. Taken together, the new approach of utilizing low m/z fragments can be applied to distinguish, identify, and quantify 13C-amino acids labeled at various positions, either in the backbone or side chain.

  20. Dissociative State and Competence

    Directory of Open Access Journals (Sweden)

    Yu-Ju Lin

    2007-10-01

    Full Text Available This report presents the results of forensic evaluation of the civil competence of a case of alleged dissociative identity disorder (DID and discusses whether such dissociative states substantially jeopardize civil competence. A 40-year-old woman claimed that she had had many personalities since her college days. From the age of 37 to 40, she shopped excessively, which left her with millions of dollars of debt. She ascribed her shopping to a certain identity state, over which she had no control. (In this article, we use the term identity state to replace personality as an objective description of a mental state. She thus raised the petition of civil incompetence. During the forensic evaluation, it was found that the identity states were relatively stable and mutually aware of each other. The switch into another identity state was sometimes under voluntary control. The subject showed consistency and continuity in behavioral patterns across the different identity states, and no matter which identity state she was in, there was no evidence of impairment in her factual knowledge of social situations and her capacity for managing personal affairs. We hence concluded that she was civilly competent despite the claimed DID. Considering that the existence and diagnosis of DID are still under dispute and a diagnosis of DID alone is not sufficient to interdict a person's civil right, important clinical and forensic issues remain to be answered.

  1. Characterization of nitrated sugar alcohols by atmospheric-pressure chemical-ionization mass spectrometry.

    Science.gov (United States)

    Ostrinskaya, Alla; Kelley, Jude A; Kunz, Roderick R

    2017-02-28

    The nitrated sugar alcohols mannitol hexanitrate (MHN), sorbitol hexanitrate (SHN) and xylitol pentanitrate (XPN) are in the same class of compounds as the powerful military-grade explosive pentaerythritol tetranitrate (PETN) and the homemade explosive erythritol tetranitrate (ETN) but, unlike for PETN and ETN, ways to detect MHN, SHN and XPN by mass spectrometry (MS) have not been fully investigated. Atmospheric-pressure chemical-ionization mass spectrometry (APCI-MS) was used to detect ions characteristic of nitrated sugar alcohols. APCI time-of-flight mass spectrometry (APCI-TOF MS) and collision-induced dissociation tandem mass spectrometry (CID MS/MS) were used for confirmation of each ion assignment. In addition, the use of the chemical ionization reagent dichloromethane was investigated to improve sensitivity and selectivity for detection of MHN, SHN and XPN. All the nitrated sugar alcohols studied followed similar fragmentation pathways in the APCI source. MHN, SHN and XPN were detectable as fragment ions formed by the loss of NO 2 , HNO 2 , NO 3 , and CH 2 NO 2 groups, and in the presence of dichloromethane chlorinated adduct ions were observed. It was determined that in MS/MS mode, chlorinated adducts of MHN and SHN had the lowest limits of detection (LODs), while for XPN the lowest LOD was for the [XPN-NO 2 ] - fragment ion. Partially nitrated analogs of each of the three compounds were also present in the starting materials, and ions attributable to these compounds versus those formed from in-source fragmentation of MHN, SHN, and XPN were distinguished and assigned using liquid chromatography APCI-MS and ESI-MS. The APCI-MS technique provides a selective and sensitive method for the detection of nitrated sugar alcohols. The methods disclosed here will benefit the area of explosives trace detection for counterterrorism and forensics. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Surface acoustic wave nebulization of peptides as a microfluidic interface for mass spectrometry.

    Science.gov (United States)

    Heron, Scott R; Wilson, Rab; Shaffer, Scott A; Goodlett, David R; Cooper, Jonathan M

    2010-05-15

    We describe the fabrication of a surface acoustic wave (SAW) device on a LiNbO(3) piezoelectric transducer for the transfer of nonvolatile analytes to the gas phase at atmospheric pressure (a process referred to as nebulization or atomization). We subsequently show how such a device can be used in the field of mass spectrometry (MS) detection, demonstrating that SAW nebulization (SAWN) can be performed either in a discontinuous or pulsed mode, similar to that for matrix assisted laser desorption ionization (MALDI) or in a continuous mode like electrospray ionization (ESI). We present data showing the transfer of peptides to the gas phase, where ions are detected by MS. These peptide ions were subsequently fragmented by collision-induced dissociation, from which the sequence was assigned. Unlike MALDI mass spectra, which are typically contaminated with matrix ions at low m/z, the SAWN generated spectra had no such interference. In continuous mode, the SAWN plume was sampled on a microsecond time scale by a linear ion trap mass spectrometer and produced multiply charged peptide precursor ions with a charge state distribution shifted to higher m/z compared to an identical sample analyzed by ESI. The SAWN technology also provides the opportunity to re-examine a sample from a flat surface, repeatedly. The process can be performed without the need for capillaries, which can clog, reservoirs, which dilute the sample, and electrodes, which when in direct contact with sample, cause unwanted electrochemical oxidation. In both continuous and pulsed sampling modes, the quality of precursor ion scans and tandem mass spectra of peptides was consistent across the plume's lifetime.

  3. Hyperglycemia associated dissociative fugue (organic dissociative disorder) in an elderly.

    Science.gov (United States)

    Ram, Dushad; Ashoka, H G; Gowdappa, Basavnna

    2015-01-01

    Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

  4. Hyperglycemia associated dissociative fugue (organic dissociative disorder) in an elderly

    OpenAIRE

    Ram, Dushad; Ashoka, H. G; Gowdappa, Basavnna

    2015-01-01

    Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

  5. Hyperglycemia associated dissociative fugue (organic dissociative disorder in an elderly

    Directory of Open Access Journals (Sweden)

    Dushad Ram

    2015-01-01

    Full Text Available Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

  6. Ion Mobility Spectrometry-Mass Spectrometry Coupled with Gas-Phase Hydrogen/Deuterium Exchange for Metabolomics Analyses

    Science.gov (United States)

    Maleki, Hossein; Karanji, Ahmad K.; Majuta, Sandra; Maurer, Megan M.; Valentine, Stephen J.

    2018-02-01

    Ion mobility spectrometry-mass spectrometry (IMS-MS) in combination with gas-phase hydrogen/deuterium exchange (HDX) and collision-induced dissociation (CID) is evaluated as an analytical method for small-molecule standard and mixture characterization. Experiments show that compound ions exhibit unique HDX reactivities that can be used to distinguish different species. Additionally, it is shown that gas-phase HDX kinetics can be exploited to provide even further distinguishing capabilities by using different partial pressures of reagent gas. The relative HDX reactivity of a wide variety of molecules is discussed in light of the various molecular structures. Additionally, hydrogen accessibility scoring (HAS) and HDX kinetics modeling of candidate ( in silico) ion structures is utilized to estimate the relative ion conformer populations giving rise to specific HDX behavior. These data interpretation methods are discussed with a focus on developing predictive tools for HDX behavior. Finally, an example is provided in which ion mobility information is supplemented with HDX reactivity data to aid identification efforts of compounds in a metabolite extract.

  7. DETERMINATION OF MUSHROOM TOXIN ALPHA-AMANITIN IN SERUM BY LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY AFTER SOLID-PHASE EXTRACTION

    Directory of Open Access Journals (Sweden)

    Maja Vujović

    2015-03-01

    Full Text Available Alpha-amanitin is a cyclic peptide which belongs to a large group of mushroom toxins known as amatoxins. Being responsible for the majority of fatal mushroom poisonings, they require rapid detection and excretion from the body fluids. In accordance with these requirements, a simple and an accurate method was developed for successful identification and quantification of alpha-amanitin in serum with electrospray liquid chromatography–mass spectrometry (LC-ESI-MS after collision-induced dissociation. The method conforms to the established International Conference on Harmonization Q2A/Q2B 1996 guidelines on the validation of analytical methods. Linearity, precision, extraction recovery and stability test on blank serum spiked with alpha-amanitin and stored in different conditions met the acceptance criteria. The obtained calibration curve was linear over the concentration range 5-100 ng/mL with a lower limit of quantification (LOQ of 5 ng/mL and limit of detection (LOD of 2.5 ng/mL. The mean intra- and inter-day precision and accuracy were 6.05% and less than ±15% of nominal values, respectively. The neutral solid phase extraction with copolymer hydrophilic–lipophilic balance cartridges was found optimal for sample preparation with the mean recovery of 91.94%. The proposed method demonstrated high sensitivity and selectivity which can be useful both for clinical and forensic toxicology analysis of alpha-amanitin at low concentrations.

  8. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 2. Assessing Charge Site Location and Isotope Scrambling

    Science.gov (United States)

    Khakinejad, Mahdiar; Ghassabi Kondalaji, Samaneh; Donohoe, Gregory C.; Valentine, Stephen J.

    2016-03-01

    Ion mobility spectrometry (IMS) coupled with gas-phase hydrogen deuterium exchange (HDX)-mass spectrometry (MS) and molecular dynamic simulations (MDS) has been used for structural investigation of anions produced by electrospraying a sample containing a synthetic peptide having the sequence KKDDDDDIIKIIK. In these experiments the potential of the analytical method for locating charge sites on ions as well as for utilizing collision-induced dissociation (CID) to reveal the degree of deuterium uptake within specific amino acid residues has been assessed. For diffuse (i.e., more elongated) [M - 2H]2- ions, decreased deuterium content along with MDS data suggest that the D4 and D6 residues are charge sites, whereas for the more diffuse [M - 3H]3- ions, the data suggest that the D4, D7, and the C-terminus are deprotonated. Fragmentation of mobility-selected, diffuse [M - 2H]2- ions to determine deuterium uptake at individual amino acid residues reveals a degree of deuterium retention at incorporation sites. Although the diffuse [M - 3H]3- ions may show more HD scrambling, it is not possible to clearly distinguish HD scrambling from the expected deuterium uptake based on a hydrogen accessibility model. The capability of the IMS-HDX-MS/MS approach to provide relevant details about ion structure is discussed. Additionally, the ability to extend the approach for locating protonation sites on positively-charged ions is presented.

  9. Rapid detection of sugar alcohol precursors and corresponding nitrate ester explosives using direct analysis in real time mass spectrometry.

    Science.gov (United States)

    Sisco, Edward; Forbes, Thomas P

    2015-04-21

    This work highlights the rapid detection of nitrate ester explosives and their sugar alcohol precursors by direct analysis in real time mass spectrometry (DART-MS) using an off-axis geometry. Demonstration of the effect of various parameters, such as ion polarity and in-source collision induced dissociation (CID) on the detection of these compounds is presented. Sensitivity of sugar alcohols and nitrate ester explosives was found to be greatest in negative ion mode with sensitivities ranging from hundreds of picograms to hundreds of nanograms, depending on the characteristics of the particular molecule. Altering the in-source CID potential allowed for acquisition of characteristic molecular ion spectra as well as fragmentation spectra. Additional studies were completed to identify the role of different experimental parameters on the sensitivity for these compounds. Variables that were examined included the DART gas stream temperature, the presence of a related compound (i.e., the effect of a precursor on the detection of a nitrate ester explosive), incorporation of dopant species and the role of the analysis surface. It was determined that each variable affected the response and detection of both sugar alcohols and the corresponding nitrate ester explosives. From this work, a rapid and sensitive method for the detection of individual sugar alcohols and corresponding nitrate ester explosives, or mixtures of the two, has been developed, providing a useful tool in the real-world identification of homemade explosives.

  10. Analysis of oversulfation in biglycan chondroitin/dermatan sulfate oligosaccharides by chip-based nanoelectrospray ionization multistage mass spectrometry.

    Science.gov (United States)

    Flangea, Corina; Sisu, Eugen; Seidler, Daniela G; Zamfir, Alina D

    2012-01-15

    Biglycan (BGN) is a small proteoglycan that consists of a protein core containing leucine-rich repeat regions and two glycosaminoglycan (GAG) chains of either chondroitin sulfate (CS) or dermatan sulfate (DS) type. The development of novel, highly efficient analytical methods for structural identification of BGN-derived CS/DS motifs, possibly implicated in biological events, is currently the focus of research. In this work, an improved analytical method based on fully automated chip-nanoelectrospray ionization (nanoESI) in conjunction with high-capacity ion trap (HCT) multistage mass spectrometry (MS) by collision-induced dissociation (CID) was for the first time applied to BGN CS/DS oligosaccharide analysis. The CS/DS chains were released from transfected 293 BGN by β-elimination. The chain was digested with AC I lyase, and the resulting mixture was purified and subsequently separated by size exclusion chromatography (SEC). Di- and tetrasaccharide fractions were pooled and characterized in detail using the developed chip-nanoESI protocol. The chip-nanoESI MS profile in the negative ion mode revealed the presence of under-, regularly, and oversulfated species in both di- and tetrasaccharide fractions. CID MS(2)-MS(3) yielded sequence patterns consistent with unusual oversulfated 4,5-Δ-GlcA(2S)-GalNAc(4S) and 4,5-Δ-GlcA(2S)-GalNAc(6S)-IdoA(2S)-GalNAc(6S) motifs. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Dissociation: a developmental psychoneurobiological perspective

    African Journals Online (AJOL)

    Adele

    ... the stream of con- sciousness and memory.1 It is a frequent symptom of a range ... infant for long time spans in an extremely disturbed psycho- biological state that ... Advantage: Dissociation is adaptive in the short-term. Dissociation can be ...

  12. Dissociative recombination of dications

    International Nuclear Information System (INIS)

    Seiersen, K.; Heber, O.; Jensen, M.J.; Safvan, C.P.; Andersen, L. H.

    2003-01-01

    Dissociative recombination (DR) of doubly-charged positive ions has been studied at the heavy ion storage ring ASTRID. Low-energy electrons were scattered on the dication of the N 2 molecule, and the absolute cross section was measured in the energy range of 10 -4 -50 eV. From the measured cross section, a thermal rate coefficient of 5.8x10 -7 cm 3 s -1 at 300 K was extracted. Furthermore, we present new results on the CO 2+ DR rate, and a summary and comparison of measured DR rate coefficients for both the singly and doubly-charged ions of CO, CO 2 , and N 2 is presented

  13. Quarkonium dissociation by anisotropy

    Science.gov (United States)

    Chernicoff, Mariano; Fernández, Daniel; Mateos, David; Trancanelli, Diego

    2013-01-01

    We compute the screening length for quarkonium mesons moving through an anisotropic, strongly coupled mathcal{N} = 4 super Yang-Mills plasma by means of its gravity dual. We present the results for arbitrary velocities and orientations of the mesons, as well as for arbitrary values of the anisotropy. The anisotropic screening length can be larger or smaller than the isotropic one, and this depends on whether the comparison is made at equal temperatures or at equal entropy densities. For generic motion we find that: (i) mesons dissociate above a certain critical value of the anisotropy, even at zero temperature; (ii) there is a limiting velocity for mesons in the plasma, even at zero temperature; (iii) in the ultra-relativistic limit the screening length scales as (1 - v 2)ɛ with ɛ = 1 /2, in contrast with the isotropic result ɛ = 1 /4.

  14. Dissociation - a preliminary contextual model

    Directory of Open Access Journals (Sweden)

    C Krüger

    2007-02-01

    Full Text Available Background. The Diagnostic and Statistical Manual of Mental Disorders (DSM system has certain limitations when applied to two South African examples of dissociation, because it is descriptive (non-explanatory and focuses on intrapsychic (non-communal processes. Even the existing Western explanatory models of dissociation fail to accommodate fully the communal aspects of dissociation in our South African context. Objectives and methods. The aim was to explore an expanded perspective on dissociation that does not limit it to an intrapsychic phenomenon, but that accounts for the interrelatedness of individuals within their social context. Auto-ethnography was used. In this article a collective, socially orientated, contextual hermeneutic was applied to two local examples of dissociation. Three existing Western models were expanded along multicontextual, collective lines, for them to be more useful in the pluralistic South African context. Results. This preliminary contextual model of dissociation includes a person’s interpersonal, socio-cultural, and spiritual contexts, in addition to the intrapsychic context. Dissociation is considered to be a normal information-processing tool that maintains balanced, coherent selves-in-society, i.e. individuals connected to each other. In the South African context dissociation appears mostly as a normal phenomenon and seldom as a sign of mental illness. Dissociation is pivotal for the normal construction of individual and communal identities in the face of conflicting sets of information from various contexts. Dissociation may help individuals or communities to survive in a world of conflicting messages, where conflict is often interpersonal/cultural/societal in nature, rather than primarily intrapsychic. Conclusions. This model should be developed and evaluated further. Such evaluation would require suitable new local terminology.

  15. Laser ionization and dissociation of hydrogen

    International Nuclear Information System (INIS)

    Buck, J.D.

    1987-01-01

    Experiments undertaken to further characterize the spectroscopic and photophysical properties of some important excited singlet states of molecular hydrogen and its deuterium isotopes are described. Attention was centered on high vibrational levels of the B, C, and B' states within about 1000 cm -1 of the second dissociation limit. A double-resonance excitation scheme was needed to access levels with a large average bond distance from the ground state. Two-photon absorption of tunable uv-laser radiation-pumped ground-state hydrogen molecules into selected rovibronic levels of the metastable EF double-minimum electronic state. A second tunable near-IR probe laser was scanned to generate ions by resonant multiphoton ionization, where the resonant levels were provided by B, C, B', and other levels near the dissociation limit. New information was obtained regarding line shapes and intensities. Time-of-flight ion mass selection permitted observation of additional excitation channels with dissociation superimposed on the ionization process to produce protons

  16. Strategies in protein sequencing and characterization: Multi-enzyme digestion coupled with alternate CID/ETD tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Nardiello, Donatella; Palermo, Carmen, E-mail: carmen.palermo@unifg.it; Natale, Anna; Quinto, Maurizio; Centonze, Diego

    2015-01-07

    Highlights: • Multi-enzyme digestion for protein sequencing and characterization by CID/ETD. • Simultaneous use of trypsin/chymotrypsin for the maximization of sequence. • Identification of PTMs, sequence variants and species-specific residues. • Increase of accuracy in sequence assignments by orthogonal fragmentation techniques. - Abstract: A strategy based on a simultaneous multi-enzyme digestion coupled with electron transfer dissociation (ETD) and collision-induced dissociation (CID) was developed for protein sequencing and characterization, as a valid alternative platform in ion-trap based proteomics. The effect of different proteolytic procedures using chymotrypsin, trypsin, a combination of both, and Lys-C, was carefully evaluated in terms of number of identified peptides, protein coverage, and score distribution. A systematic comparison between CID and ETD is shown for the analysis of peptides originating from the in-solution digestion of standard caseins. The best results were achieved with a trypsin/chymotrypsin mix combined with CID and ETD operating in alternating mode. A post-database search validation of MS/MS dataset was performed, then, the matched peptides were cross checked by the evaluation of ion scores, rank, number of experimental product ions, and their relative abundances in the MS/MS spectrum. By integrated CID/ETD experiments, high quality-spectra have been obtained, thus allowing a confirmation of spectral information and an increase of accuracy in peptide sequence assignments. Overlapping peptides, produced throughout the proteins, reduce the ambiguity in mapping modifications between natural variants and animal species, and allow the characterization of post translational modifications. The advantages of using the enzymatic mix trypsin/chymotrypsin were confirmed by the nanoLC and CID/ETD tandem mass spectrometry of goat milk proteins, previously separated by two-dimensional gel electrophoresis.

  17. Dissociative symptomatology in cancer patients

    Science.gov (United States)

    Civilotti, Cristina; Castelli, Lorys; Binaschi, Luca; Cussino, Martina; Tesio, Valentina; Di Fini, Giulia; Veglia, Fabio; Torta, Riccardo

    2015-01-01

    Introduction: The utilization of the post-traumatic stress disorder (PTSD) diagnostic spectrum is currently being debated to categorize psychological adjustment in cancer patients. The aims of this study were to: (1) evaluate the presence of cancer-related traumatic dissociative symptomatology in a sample of cancer patients; (2) examine the correlation of cancer-related dissociation and sociodemographic and medical variables, anxiety, depression, and post-traumatic stress symptomatology; (3) investigate the predictors of cancer-related dissociation. Methods: Ninety-two mixed cancer patients (mean age: 58.94, ds = 10.13) recruited from two hospitals in northern Italy were administered a questionnaire on sociodemographic and medical characteristics, the Karnofsky Scale to measure the level of patient activity and medical care requirements, the Hospital Anxiety and Depression Scale (HADS) to evaluate the presence of anxiety and depression, the Impact of Event Scale Revised (IES-R) to assess the severity of intrusion, avoidance, and hypervigilance, and the Peritraumatic Dissociative Experiences Questionnaire (PDEQ) to quantify the traumatic dissociative symptomatology. Results: 31.5% of participants report a PDEQ score above the cutoff. The results indicated that dissociative symptomatology was positively correlated with HADS scores (HADS-Anxiety: r = 0.476, p dissociative symptomatology. The results converged on a three predictor model revealing that IES-R-Intrusion, IES-R-Avoidance, and IES-R-Hyperarousal accounted for 53.9% of the explained variance. Conclusion: These findings allow us to hypothesize a specific psychological reaction which may be ascribed to the traumatic spectrum within the context of cancer, emphasizing the close relationship between the origin of dissociative constituents which, according to the scientific literature, compose the traumatic experience. Our results have implications for understanding dissociative symptomatology in a cancer

  18. Systematics of 2-body diffractive dissociations and search of double diffractive dissociation in K-p interactions at 14.3 GeV/c

    International Nuclear Information System (INIS)

    Pons, Yvette.

    1977-12-01

    The diffractive dissociation mechanism is shown to be general when looking at 22 mesonic or baryonic threshold enhancements. The dissociation systems are all produced peripherally and present the property of slope-mass correlation. The production slopes and cross-sections mainly depend on the diffractive excitation mass. The comparison of the results with those from the I.S.R. shows that dissociation systems are very similar in their effective mass shape, momentum transfer structure and angular distributions at center-of-mass energies differing by a factor of ten. Evidence for double diffractive dissociation mechanism is found in 2 exclusive reactions at a cross section level of 5-10+-2 μb. The factorisation hypothesis seems well verified [fr

  19. Dissociative absorption: An empirically unique, clinically relevant, dissociative factor.

    Science.gov (United States)

    Soffer-Dudek, Nirit; Lassri, Dana; Soffer-Dudek, Nir; Shahar, Golan

    2015-11-01

    Research of dissociative absorption has raised two questions: (a) Is absorption a unique dissociative factor within a three-factor structure, or a part of one general dissociative factor? Even when three factors are found, the specificity of the absorption factor is questionable. (b) Is absorption implicated in psychopathology? Although commonly viewed as "non-clinical" dissociation, absorption was recently hypothesized to be specifically associated with obsessive-compulsive symptoms. To address these questions, we conducted exploratory and confirmatory factor analyses on 679 undergraduates. Analyses supported the three-factor model, and a "purified" absorption scale was extracted from the original inclusive absorption factor. The purified scale predicted several psychopathology scales. As hypothesized, absorption was a stronger predictor of obsessive-compulsive symptoms than of general psychopathology. In addition, absorption was the only dissociative scale that longitudinally predicted obsessive-compulsive symptoms. We conclude that absorption is a unique and clinically relevant dissociative tendency that is particularly meaningful to obsessive-compulsive symptoms. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Purification and Quantification of an Isomeric Compound in a Mixture by Collisional Excitation in Multistage Mass Spectrometry Experiments.

    Science.gov (United States)

    Jeanne Dit Fouque, Dany; Maroto, Alicia; Memboeuf, Antony

    2016-11-15

    The differentiation, characterization, and quantification of isomers and/or isobars in mixtures is a recurrent problem in mass spectrometry and more generally in analytical chemistry. Here we present a new strategy to assess the purity of a compound that is susceptible to be contaminated with another isomeric side-product in trace levels. Providing one of the isomers is available as pure sample, this new strategy allows the detection of isomeric contamination. This is done thanks to a "gas-phase collisional purification" inside an ion trap mass spectrometer paving the way for an improved analysis of at least similar samples. This strategy consists in using collision induced dissociation (CID) multistage mass spectrometry (MS 2 and MS 3 ) experiments and the survival yield (SY) technique. It has been successfully applied to mixtures of cyclic poly( L -lactide) (PLA) with increasing amounts of its linear topological isomer. Purification in gas phase of PLA mixtures was established based on SY curves obtained in MS 3 mode: all samples gave rise to the same SY curve corresponding then to the pure cyclic component. This new strategy was sensitive enough to detect traces of linear PLA (<3%) in a sample of cyclic PLA that was supposedly pure according to other characterization techniques ( 1 H NMR, MALDI-HRMS, and size-exclusion chromatography). Moreover, in this case, the presence of linear isomer was undetectable according to MS/MS or MS/MS/MS analysis only as fragment ions are also of the same m/z values. This type of approach could easily be implemented in hyphenated mass spectrometric techniques to improve the structural and quantitative analysis of complex samples.

  1. Characterization and quantitative analysis of surfactants in textile wastewater by liquid chromatography/quadrupole-time-of-flight mass spectrometry.

    Science.gov (United States)

    González, Susana; Petrović, Mira; Radetic, Maja; Jovancic, Petar; Ilic, Vesna; Barceló, Damià

    2008-05-01

    A method based on the application of ultra-performance liquid chromatography (UPLC) coupled to hybrid quadrupole-time-of-flight mass spectrometry (QqTOF-MS) with an electrospray (ESI) interface has been developed for the screening and confirmation of several anionic and non-ionic surfactants: linear alkylbenzenesulfonates (LAS), alkylsulfate (AS), alkylethersulfate (AES), dihexyl sulfosuccinate (DHSS), alcohol ethoxylates (AEOs), coconut diethanolamide (CDEA), nonylphenol ethoxylates (NPEOs), and their degradation products (nonylphenol carboxylate (NPEC), octylphenol carboxylate (OPEC), 4-nonylphenol (NP), 4-octylphenol (OP) and NPEO sulfate (NPEO-SO4). The developed methodology permits reliable quantification combined with a high accuracy confirmation based on the accurate mass of the (de)protonated molecules in the TOFMS mode. For further confirmation of the identity of the detected compounds the QqTOF mode was used. Accurate masses of product ions obtained by performing collision-induced dissociation (CID) of the (de)protonated molecules of parent compounds were matched with the ions obtained for a standard solution. The method was applied for the quantitative analysis and high accuracy confirmation of surfactants in complex mixtures in effluents from the textile industry. Positive identification of the target compounds was based on accurate mass measurement of the base peak, at least one product ion and the LC retention time of the analyte compared with that of a standard. The most frequently surfactants found in these textile effluents were NPEO and NPEO-SO4 in concentrations ranging from 0.93 to 5.68 mg/L for NPEO and 0.06 to 4.30 mg/L for NPEO-SO4. AEOs were also identified.

  2. Assignment by Negative-Ion Electrospray Tandem Mass Spectrometry of the Tetrasaccharide Backbones of Monosialylated Glycans Released from Bovine Brain Gangliosides

    Science.gov (United States)

    Chai, Wengang; Zhang, Yibing; Mauri, Laura; Ciampa, Maria G.; Mulloy, Barbara; Sonnino, Sandro; Feizi, Ten

    2018-05-01

    Gangliosides, as plasma membrane-associated sialylated glycolipids, are antigenic structures and they serve as ligands for adhesion proteins of pathogens, for toxins of bacteria, and for endogenous proteins of the host. The detectability by carbohydrate-binding proteins of glycan antigens and ligands on glycolipids can be influenced by the differing lipid moieties. To investigate glycan sequences of gangliosides as recognition structures, we have underway a program of work to develop a "gangliome" microarray consisting of isolated natural gangliosides and neoglycolipids (NGLs) derived from glycans released from them, and each linked to the same lipid molecule for arraying and comparative microarray binding analyses. Here, in the first phase of our studies, we describe a strategy for high-sensitivity assignment of the tetrasaccharide backbones and application to identification of eight of monosialylated glycans released from bovine brain gangliosides. This approach is based on negative-ion electrospray mass spectrometry with collision-induced dissociation (ESI-CID-MS/MS) of the desialylated glycans. Using this strategy, we have the data on backbone regions of four minor components among the monosialo-ganglioside-derived glycans; these are of the ganglio-, lacto-, and neolacto-series.

  3. Tandem mass spectrometry approach for the investigation of the steroidal metabolism: structure-fragmentation relationship (SFR) in anabolic steroids and their metabolites by ESI-MS/MS analysis.

    Science.gov (United States)

    Musharraf, Syed Ghulam; Ali, Arslan; Khan, Naik Tameem; Yousuf, Maria; Choudhary, Muhammad Iqbal; Atta-ur-Rahman

    2013-02-01

    Electrospray ionization tandem mass spectrometry (ESI-MS/MS) was used to investigate the effect of different substitutions introduced during metabolism on fragmentation patterns of four anabolic steroids including methyltestosterone, methandrostenolone, cis-androsterone and adrenosterone, along with their metabolites. Collision-induced dissociation (CID) analysis was performed to correlate the major product ions of 19 steroids with structural features. The analysis is done to portray metabolic alteration, such as incorporation or reduction of double bonds, hydroxylations, and/or oxidation of hydroxyl moieties to keto functional group on steroidal skeleton which leads to drastically changed product ion spectra from the respective classes of steroids, therefore, making them difficult to identify. The comparative ESI-MS/MS study also revealed some characteristic peaks to differentiate different steroidal metabolites and can be useful for the unambiguous identification of anabolic steroids in biological fluid. Moreover, LC-ESI-MS/MS analysis of fermented extract of methyltestosterone, obtained by Macrophomina phaseolina was also investigated. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Trace analysis of icariin in human serum with dansyl chloride derivatization after oral administration of Epimedium decoction by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Gong, Yinhan; Yip, See Chung; Thamarai, Sennappan Kanagamani; Zhang, Jie; Lee, Hian Kee; Yong, E L

    2007-12-15

    Epimedium herbs are a type of complex traditional Chinese medicine (TCM) with high estrogenic bioactivity. The Epimedium herbal decoction mixture contains many compounds including icariin that can exert potent effects on numerous physiological processes related to human health. An ultrasensitive liquid chromatography tandem mass spectrometric (LC-MS/MS) method has been developed to determine trace levels of icariin in human serum with dansyl chloride derivatization after oral administration of the Epimedium herbal decoctions. The dansyl-icariin showed an intense protonated molecular ion at m/z 910. The collision-induced dissociation of this ion formed a distinctive product at m/z 764, corresponding to a characteristic removal of a rhamnose sugar moiety of icariin. The selected reaction monitoring, based on the m/z 910-->764 transition, was highly specific and ultrasenstive for icariin in human serum samples. The lower limit of quantitation was 10 pg/mL icariin spiked into blank serum. The ranges of coefficients of variation for interday assays and intraday assays were 0-15.0% and 1.1-17.5%, respectively, for a wide linear range from 10 pg/mL to 4 ng/mL. This method was successfully applied to measure trace levels of icariin in a human serum after oral administration of Epimedium decoction within 48 h for the first time.

  5. Mass spectrometric determination of partial electron impact ionization cross sections of No, No2, and N2O from threshold up to 180 eV

    International Nuclear Information System (INIS)

    Kim, Y. B.

    1982-01-01

    Electron impact ionization of nitric oxide (NO), nitrogen dioxide (NO 2 ) and nitrous oxide (N 2 O) has been studied as a function of electron energy up to 180 eV with a double focussing mass spectrometer Varian MAT CH5 and an improved Nier type electron impact ion source. Relative partial ionization cross sections were measured for the processes NO + + 2e, NO ++ + 3e, and NO 2 + e -> NO + 2 + 2e, NO ++ + 3e and N 2 O + e -> N 2 O + + 2e. An accurate measurement of the cross section ratios q(NO 2+ /NO)/q(NO + /NO) and q(NO 2 2 /NO 2 )/q(NO + 2 /NO 2 ) has been made. Relative cross section functions were calibrated absolutely with two different normalization methods. Moreover, both metastable and collision induced dissociations of N 2 O + were studied quantitatively using the technique of decoupling the acceleration and deflection electric fields. Using the n- th root extrapolation the following ionization potentials have been derived from the cross section functions near threshold: NO + (X 1 Σ + ); NO ++ ; NO + 2 ; NO 2 ++ ; N 2 O + (X 2 π). These results are compared with previous measurements and theoretical calculations, where available. Part of the results presented have been already published in seven papers by the author. (Author)

  6. Dissociation Energies of Diatomic Molecules

    International Nuclear Information System (INIS)

    Qun-Chao, Fan; Wei-Guo, Sun

    2008-01-01

    Molecular dissociation energies of 10 electronic states of alkali molecules of KH, 7 LiD, 7 LiH, 6 LiH, NaK, NaLi and NaRb are studied using the highest three accurate vibrational energies of each electronic state, and an improved parameter-free analytical formula which is obtained starting from the LeRoy–Bernstein vibrational energy expression near the dissociation limit. The results show that as long as the highest three vibrational energies are accurate, the current analytical formula will give accurate theoretical dissociation energies D e theory , which are in excellent agreement with the experimental dissociation energies D e expt . (atomic and molecular physics)

  7. Neural complexity, dissociation, and schizophrenia

    Czech Academy of Sciences Publication Activity Database

    Bob, P.; Šusta, M.; Chládek, Jan; Glaslová, K.; Fedor-Ferybergh, P.

    2007-01-01

    Roč. 13, č. 10 (2007), HY1-5 ISSN 1234-1010 Institutional research plan: CEZ:AV0Z20650511 Keywords : neural complexity * dissociation * schizophrenia Subject RIV: FH - Neurology Impact factor: 1.607, year: 2007

  8. Dissociative Tendencies and Traffic Incidents

    Directory of Open Access Journals (Sweden)

    Valle, Virginia

    2012-01-01

    Full Text Available This paper analyses the relationship between dissociative experiences and road traffic incidents (crashes and traffic tickets in drivers (n=295 from Mar del Plata (Argentina city. A self-report questionnaire was applied to assess traffic crash involvement and sociodemographic variables. Dissociative tendencies were assessed by a modified version of the DES scale. To examine differences in DES scores tests of the difference of means were applied. Drivers who reported to be previously involved in traffic incidents obtained higher puntuations in the dissociative experiences scale than drivers who did not report such events. This result is observed for the total scale and for the three sub-scales (absorption, amnesia and depersonalization. However, differences appeared mainly for minor damage collisions. Further studies are needed to evaluate the role of dissociative tendencies as a risk factor in road traffic safety.

  9. Atrioventricular Dissociation after Electroconvulsive Therapy

    Directory of Open Access Journals (Sweden)

    Siegfried William Yu

    2011-01-01

    Full Text Available Electroconvulsive therapy (ECT is increasingly used as a treatment for psychiatric disorders. Cardiac effects are the principal cause of medical complications in these patients. We report a case of atrioventricular (AV dissociation that occurred after ECT that was treated with pacemaker implantation. The mechanisms contributing to the onset of AV dissociation in this patient, and the management and rationale for device therapy, in light of the most recent guidelines, are reviewed.

  10. Dissociative disorders in DSM-5.

    Science.gov (United States)

    Spiegel, David; Lewis-Fernández, Roberto; Lanius, Ruth; Vermetten, Eric; Simeon, Daphne; Friedman, Matthew

    2013-01-01

    The rationale, research literature, and proposed changes to the dissociative disorders and conversion disorder in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) are presented. Dissociative identity disorder will include reference to possession as well as identity fragmentation, to make the disorder more applicable to culturally diverse situations. Dissociative amnesia will include dissociative fugue as a subtype, since fugue is a rare disorder that always involves amnesia but does not always include confused wandering or loss of personality identity. Depersonalization disorder will include derealization as well, since the two often co-occur. A dissociative subtype of posttraumatic stress disorder (PTSD), defined by the presence of depersonalization or derealization in addition to other PTSD symptoms, is being recommended, based upon new epidemiological and neuroimaging evidence linking it to an early life history of adversity and a combination of frontal activation and limbic inhibition. Conversion disorder (functional neurological symptom disorder) will likely remain with the somatic symptom disorders, despite considerable dissociative comorbidity.

  11. Electron ionization and dissociation of aliphatic amino acids

    Science.gov (United States)

    Papp, P.; Shchukin, P.; Kočíšek, J.; Matejčík, Š.

    2012-09-01

    We present experimental and theoretical study of electron ionization and dissociative ionization to the gas phase amino acids valine, leucine, and isoleucine. A crossed electron/molecular beams technique equipped with quadrupole mass analyzer has been applied to measure mass spectra and ion efficiency curves for formation of particular ions. From experimental data the ionization energies of the molecules and the appearance energies of the fragment ions were determined. Ab initio calculations (Density Functional Theory and G3MP2 methods) were performed in order to calculate the fragmentation paths and interpret the experimental data. The experimental ionization energies of parent molecules [P]+ 8.91 ± 0.05, 8.85 ± 0.05, and 8.79 ± 0.05 eV and G3MP2 ionization energies (adiabatic) of 8.89, 8.88, and 8.81 eV were determined for valine, leucine, and isoleucine, respectively, as well as the experimental and theoretical threshold energies for dissociative ionization channels. The comparison of experimental data with calculations resulted in identification of the ions as well as the neutral fragments formed in the dissociative reactions. Around 15 mass/charge ratio fragments were identified from the mass spectra by comparison of experimental appearance energies with calculated reaction enthalpies for particular dissociative reactions.

  12. Mass spectrometric approaches for the identification of anthracycline analogs produced by actinobacteria.

    Science.gov (United States)

    Bauermeister, Anelize; Zucchi, Tiago Domingues; Moraes, Luiz Alberto Beraldo

    2016-06-01

    Anthracyclines are a well-known chemical class produced by actinobacteria used effectively in cancer treatment; however, these compounds are usually produced in few amounts because of being toxic against their producers. In this work, we successfully explored the mass spectrometry versatility to detect 18 anthracyclines in microbial crude extract. From collision-induced dissociation and nuclear magnetic resonance spectra, we proposed structures for five new and identified three more anthracyclines already described in the literature, nocardicyclins A and B and nothramicin. One new compound 8 (4-[4-(dimethylamino)-5-hydroxy-4,6-dimethyloxan-2-yl]oxy-2,5,7,12-tetrahydroxy-3,10-dimethoxy-2-methyl-3,4-dihydrotetracene-1,6,11-trione) was isolated and had its structure confirmed by (1) H nuclear magnetic resonance. The anthracyclines identified in this work show an interesting aminoglycoside, poorly found in natural products, 3-methyl-rhodosamine and derivatives. This fact encouraged to develop a focused method to identify compounds with aminoglycosides (rhodosamine, m/z 158; 3-methyl-rhodosamine, m/z 172; 4'-O-acethyl-3-C-methyl-rhodosamine, m/z 214). This method allowed the detection of four more anthracyclines. This focused method can also be applied in the search of these aminoglycosides in other microbial crude extracts. Additionally, it was observed that nocardicyclin A, nothramicin and compound 8 were able to interact to DNA through a DNA-binding study by mass spectrometry, showing its potential as anticancer drugs. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Mechanistic and Kinetic Study of Singlet O2 Oxidation of Methionine by On-Line Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    Liu, Fangwei; Lu, Wenchao; Yin, Xunlong; Liu, Jianbo

    2016-01-01

    We report a reaction apparatus developed to monitor singlet oxygen ((1)O2) reactions in solution using on-line ESI mass spectrometry and spectroscopy measurements. (1)O2 was generated in the gas phase by the reaction of H2O2 with Cl2, detected by its emission at 1270 nm, and bubbled into aqueous solution continuously. (1)O2 concentrations in solution were linearly related to the emission intensities of airborne (1)O2, and their absolute scales were established based on a calibration using 9,10-anthracene dipropionate dianion as an (1)O2 trapping agent. Products from (1)O2 oxidation were monitored by UV-Vis absorption and positive/negative ESI mass spectra, and product structures were elucidated using collision-induced dissociation-tandem mass spectrometry. To suppress electrical discharge in negative ESI of aqueous solution, methanol was added to electrospray via in-spray solution mixing using theta-glass ESI emitters. Capitalizing on this apparatus, the reaction of (1)O2 with methionine was investigated. We have identified methionine oxidation intermediates and products at different pH, and measured reaction rate constants. (1)O2 oxidation of methionine is mediated by persulfoxide in both acidic and basic solutions. Persulfoxide continues to react with another methionine, yielding methionine sulfoxide as end-product albeit with a much lower reaction rate in basic solution. Density functional theory was used to explore reaction potential energy surfaces and establish kinetic models, with solvation effects simulated using the polarized continuum model. Combined with our previous study of gas-phase methionine ions with (1)O2, evolution of methionine oxidation pathways at different ionization states and in different media is described.

  14. Determination of ion mobility collision cross sections for unresolved isomeric mixtures using tandem mass spectrometry and chemometric deconvolution

    Energy Technology Data Exchange (ETDEWEB)

    Harper, Brett [Institute of Biomedical Studies, Baylor University, Waco, TX 76798 (United States); Neumann, Elizabeth K. [Department of Chemistry and Biochemistry, Baylor University, Waco, TX 76798 (United States); Stow, Sarah M.; May, Jody C.; McLean, John A. [Department of Chemistry, Vanderbilt University, Nashville, TN 37235 (United States); Vanderbilt Institute of Chemical Biology, Nashville, TN 37235 (United States); Vanderbilt Institute for Integrative Biosystems Research and Education, Nashville, TN 37235 (United States); Center for Innovative Technology, Nashville, TN 37235 (United States); Solouki, Touradj, E-mail: Touradj_Solouki@baylor.edu [Department of Chemistry and Biochemistry, Baylor University, Waco, TX 76798 (United States)

    2016-10-05

    Ion mobility (IM) is an important analytical technique for determining ion collision cross section (CCS) values in the gas-phase and gaining insight into molecular structures and conformations. However, limited instrument resolving powers for IM may restrict adequate characterization of conformationally similar ions, such as structural isomers, and reduce the accuracy of IM-based CCS calculations. Recently, we introduced an automated technique for extracting “pure” IM and collision-induced dissociation (CID) mass spectra of IM overlapping species using chemometric deconvolution of post-IM/CID mass spectrometry (MS) data [J. Am. Soc. Mass Spectrom., 2014, 25, 1810–1819]. Here we extend those capabilities to demonstrate how extracted IM profiles can be used to calculate accurate CCS values of peptide isomer ions which are not fully resolved by IM. We show that CCS values obtained from deconvoluted IM spectra match with CCS values measured from the individually analyzed corresponding peptides on uniform field IM instrumentation. We introduce an approach that utilizes experimentally determined IM arrival time (AT) “shift factors” to compensate for ion acceleration variations during post-IM/CID and significantly improve the accuracy of the calculated CCS values. Also, we discuss details of this IM deconvolution approach and compare empirical CCS values from traveling wave (TW)IM-MS and drift tube (DT)IM-MS with theoretically calculated CCS values using the projected superposition approximation (PSA). For example, experimentally measured deconvoluted TWIM-MS mean CCS values for doubly-protonated RYGGFM, RMFGYG, MFRYGG, and FRMYGG peptide isomers were 288.{sub 8} Å{sup 2}, 295.{sub 1} Å{sup 2}, 296.{sub 8} Å{sup 2}, and 300.{sub 1} Å{sup 2}; all four of these CCS values were within 1.5% of independently measured DTIM-MS values.

  15. Determination of ion mobility collision cross sections for unresolved isomeric mixtures using tandem mass spectrometry and chemometric deconvolution

    International Nuclear Information System (INIS)

    Harper, Brett; Neumann, Elizabeth K.; Stow, Sarah M.; May, Jody C.; McLean, John A.; Solouki, Touradj

    2016-01-01

    Ion mobility (IM) is an important analytical technique for determining ion collision cross section (CCS) values in the gas-phase and gaining insight into molecular structures and conformations. However, limited instrument resolving powers for IM may restrict adequate characterization of conformationally similar ions, such as structural isomers, and reduce the accuracy of IM-based CCS calculations. Recently, we introduced an automated technique for extracting “pure” IM and collision-induced dissociation (CID) mass spectra of IM overlapping species using chemometric deconvolution of post-IM/CID mass spectrometry (MS) data [J. Am. Soc. Mass Spectrom., 2014, 25, 1810–1819]. Here we extend those capabilities to demonstrate how extracted IM profiles can be used to calculate accurate CCS values of peptide isomer ions which are not fully resolved by IM. We show that CCS values obtained from deconvoluted IM spectra match with CCS values measured from the individually analyzed corresponding peptides on uniform field IM instrumentation. We introduce an approach that utilizes experimentally determined IM arrival time (AT) “shift factors” to compensate for ion acceleration variations during post-IM/CID and significantly improve the accuracy of the calculated CCS values. Also, we discuss details of this IM deconvolution approach and compare empirical CCS values from traveling wave (TW)IM-MS and drift tube (DT)IM-MS with theoretically calculated CCS values using the projected superposition approximation (PSA). For example, experimentally measured deconvoluted TWIM-MS mean CCS values for doubly-protonated RYGGFM, RMFGYG, MFRYGG, and FRMYGG peptide isomers were 288._8 Å"2, 295._1 Å"2, 296._8 Å"2, and 300._1 Å"2; all four of these CCS values were within 1.5% of independently measured DTIM-MS values.

  16. Mechanism of [m+h]+ formation in atmospheric pressure photoionization mass spectrometry: identification of propionitrile in acetonitrile with high mass accuracy measurement and tandem mass spectrometry and evidence for its involvement in the protonation phenomenon.

    Science.gov (United States)

    Kamel, Amin; Jeanville, Patrick; Colizza, Kevin; J-Rivera, Lauren Elizabeth

    2008-11-01

    The role of propionitrile in the production of [M+H]+ under atmospheric pressure photoionization (APPI) was investigated. In dopant-assisted APPI using acetone and anisole, protonated acetone and anisole radical cations were the most prominent ions observed. In dopant-free or direct APPI in acetonitrile, however, a major ion in acetonitrile was detected and identified as propionitrile, using high accuracy mass measurement and collision induced dissociation studies. Vaporizing ca. 10(-5) M althiazide and bendroflumethazide under direct APPI in acetonitrile produced their corresponding protonated species [M+H]+. In addition to protonated acetonitrile, its dimers, and acetonitrile/water clusters, protonated propionitrile, propionitrile dimer, and propionitrile/water clusters were also observed. The role of propionitrile, an impurity in acetonitrile and/or a possible product of ion-molecule reaction, in the production of [M+H]+ of althiazide and bendroflumethazide was further investigated in the absence of dopant using propionitrile-d5. The formation of [M+D]+ species was observed, suggesting a possible role of propionitrile in the protonation process. Additionally, an increase in the [M+H]+ signal of althiazide and bendroflumethazide was observed as a function of propionitrile concentration in acetonitrile. Theoretical data from the literature supported the assumption that one possible mechanism, among others, for the formation of [M+H]+ could be attributed to photo-initiated isomerization of propionitrile. The most stable isomers of propionitrile, based on their calculated ionization energy (IE) and relative energy (DeltaE), were assumed to undergo proton transfer to the analytes, and mechanisms were proposed.

  17. Ultrafast dissociation: An unexpected tool for probing molecular dynamics

    International Nuclear Information System (INIS)

    Morin, Paul; Miron, Catalin

    2012-01-01

    Highlights: ► Ultrafast dissociation has been investigated by means of XPS and mass spectrometry. ► The interplay between electron relaxation and molecular dynamics is evidenced. ► Extension toward polyatomics, clusters, adsorbed molecules is considered. ► Quantum effects (spectral hole, angular effects) evidence the molecular field anisotropy. -- Abstract: Ultrafast dissociation following core–shell excitation into an antibonding orbital led to the early observation in HBr of atomic Auger lines associated to the decay of dissociated excited atoms. The purpose of this article is to review the very large variety of systems where such a situation has been encountered, extending from simple diatomic molecules toward more complex systems like polyatomics, clusters, or adsorbed molecules. Interestingly, this phenomenon has revealed an extremely rich and powerful tool for probing nuclear dynamics and its subtle interplay with electron relaxation occurring on a comparable time scale. Consequently this review covers a surprisingly large period, starting in 1986 and still ongoing.

  18. Analysis of antioxidants in insulation cladding of copper wire: a comparison of different mass spectrometric techniques (ESI-IT, MALDI-RTOF and RTOF-SIMS).

    Science.gov (United States)

    Schnöller, Johannes; Pittenauer, Ernst; Hutter, Herbert; Allmaier, Günter

    2009-12-01

    Commercial copper wire and its polymer insulation cladding was investigated for the presence of three synthetic antioxidants (ADK STAB AO412S, Irganox 1010 and Irganox MD 1024) by three different mass spectrometric techniques including electrospray ionization-ion trap-mass spectrometry (ESI-IT-MS), matrix-assisted laser desorption/ionization reflectron time-of-flight (TOF) mass spectrometry (MALDI-RTOF-MS) and reflectron TOF secondary ion mass spectrometry (RTOF-SIMS). The samples were analyzed either directly without any treatment (RTOF-SIMS) or after a simple liquid/liquid extraction step (ESI-IT-MS, MALDI-RTOF-MS and RTOF-SIMS). Direct analysis of the copper wire itself or of the insulation cladding by RTOF-SIMS allowed the detection of at least two of the three antioxidants but at rather low sensitivity as molecular radical cations and with fairly strong fragmentation (due to the highly energetic ion beam of the primary ion gun). ESI-IT- and MALDI-RTOF-MS-generated abundant protonated and/or cationized molecules (ammoniated or sodiated) from the liquid/liquid extract. Only ESI-IT-MS allowed simultaneous detection of all three analytes in the extract of insulation claddings. The latter two so-called 'soft' desorption/ionization techniques exhibited intense fragmentation only by applying low-energy collision-induced dissociation (CID) tandem MS on a multistage ion trap-instrument and high-energy CID on a tandem TOF-instrument (TOF/RTOF), respectively. Strong differences in the fragmentation behavior of the three analytes could be observed between the different CID spectra obtained from either the IT-instrument (collision energy in the very low eV range) or the TOF/RTOF-instrument (collision energy 20 keV), but both delivered important structural information. Copyright 2009 John Wiley & Sons, Ltd.

  19. Dynamics of dissociation versus ionization in strong laser fields

    International Nuclear Information System (INIS)

    DiMauro, L.F.; Yang, B.

    1993-01-01

    In this paper, experimental results are presented which clearly demonstrate the effectiveness that an external field has in altering the dissociation dynamics. The experiment examines the strong-field dissociation dynamics of molecular hydrogen ions and its deuterated isotopes. These studies involve multiphoton excitation in the intensity regime of 10 11-14 W/cm 2 with the fundamental and second harmonic of a ND:YAG or ND:YLF laser system. Measurements include energy resolved electron and mass spectroscopy which provide useful probes in elucidating the interaction dynamics predicted by existing models. The example this in this paper, examines the strong-field dissociation of H 2 + , HD + , and D 2 + at green (0.5 μm) and (1μm) frequencies. The diatomic ions are formed via multiphonon ionization of the neutral precursor which is physically separable from the dissociation process. This study provides the first observation of the dynamics associated with the above threshold dissociation (ATD) process and analogies will be made with the more familiar above threshold ionization (ATI) phenomenon

  20. Ion collision-induced chemistry in pure and mixed loosely bound clusters of coronene and C60 molecules.

    Science.gov (United States)

    Domaracka, Alicja; Delaunay, Rudy; Mika, Arkadiusz; Gatchell, Michael; Zettergren, Henning; Cederquist, Henrik; Rousseau, Patrick; Huber, Bernd A

    2018-05-23

    Ionization, fragmentation and molecular growth have been studied in collisions of 22.5 keV He2+- or 3 keV Ar+-projectiles with pure loosely bound clusters of coronene (C24H12) molecules or with loosely bound mixed C60-C24H12 clusters by using mass spectrometry. The heavier and slower Ar+ projectiles induce prompt knockout-fragmentation - C- and/or H-losses - from individual molecules and highly efficient secondary molecular growth reactions before the clusters disintegrate on picosecond timescales. The lighter and faster He2+ projectiles have a higher charge and the main reactions are then ionization by ions that are not penetrating the clusters. This leads mostly to cluster fragmentation without molecular growth. However, here penetrating collisions may also lead to molecular growth but to a much smaller extent than with 3 keV Ar+. Here we present fragmentation and molecular growth mass distributions with 1 mass unit resolution, which reveals that the same numbers of C- and H-atoms often participate in the formation and breaking of covalent bonds inside the clusters. We find that masses close to those with integer numbers of intact coronene molecules, or with integer numbers of both intact coronene and C60 molecules, are formed where often one or several H-atoms are missing or have been added on. We also find that super-hydrogenated coronene is formed inside the clusters.

  1. [Dissociative identity disorder or schizophrenia?].

    Science.gov (United States)

    Tschöke, S; Steinert, T

    2010-01-01

    We present a case of dissociative identity disorder in which Schneiderian first rank symptoms were present besides of various states of consciousness. Thus the diagnosis of schizophrenia had to be considered. Formally, the symptoms met ICD-10 criteria for schizophrenia. However, taking into account the lack of formal thought disorder and of negative symptoms as well as a typical history of severe and prolonged traumatisation, we did not diagnose a co-morbid schizophrenic disorder. There is good evidence for the existence of psychotic symptoms among patients with dissociative disorders. However, in clinical practice this differential diagnosis is rarely considered.

  2. Rapid qualitative analysis of 2 flavonoids, rutin and silybin, in medical pills by direct analysis in real-time mass spectrometry (DART-MS) combined with in situ derivatization.

    Science.gov (United States)

    Nagy, Tibor; Kuki, Ákos; Nagy, Lajos; Zsuga, Miklós; Kéki, Sándor

    2018-03-01

    Direct analysis in real-time mass spectrometry (DART-MS) with in situ silylation was used for the rapid analysis of the flavonoids silybin ((2R,3R)-3,5,7-trihydroxy-2-[3-(4-hydroxy-3-methoxyphenyl)-2-hydroxymethyl-2,3-dihydrobenzo[1,4]dioxin-6-yl]chroman-4-one) and rutin (quercetin-3-O-rutinoside). Three different derivatization reagents, hexamethyldisilazane/trimethylchlorosilane/pyridine (HMDS/TMCS/pyridine), N,O-bis(trimethylsilyl)acetamide/trimethylchlorosilane/N-trimethylsilyimidazole (BSA/TMCS/TMSI), and N,O-bis(trimethylsilyl)trifluoroacetamide/trimethylchlorosilane (BSTFA/TMCS), were applied. Silybin and rutin were detected with various degrees of silylation, and the formation of dimers with pyridine and imidazole was also observed. HMDS/TMCS/pyridine was the best choice for the DART-MS analysis of silybin, and BSA/TMCS/TMSI was the most effective for the detection of rutin. The effects of the DART source temperature on desorption, ionization, in-source fragmentation, dimer formation, and hydrolysis of the trimethylsilyl groups were also studied. In addition, the collision-induced dissociation properties of the derivatized silybin and rutin were explored. With our in situ silylation method, the derivatized bioactive compounds in intact medical pills could also be detected by DART-MS. Copyright © 2017 John Wiley & Sons, Ltd.

  3. Identification and Quantification of N-Acyl Homoserine Lactones Involved in Bacterial Communication by Small-Scale Synthesis of Internal Standards and Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

    Science.gov (United States)

    Leipert, Jan; Treitz, Christian; Leippe, Matthias; Tholey, Andreas

    2017-12-01

    N-acyl homoserine lactones (AHL) are small signal molecules involved in the quorum sensing of many gram-negative bacteria, and play an important role in biofilm formation and pathogenesis. Present analytical methods for identification and quantification of AHL require time-consuming sample preparation steps and are hampered by the lack of appropriate standards. By aiming at a fast and straightforward method for AHL analytics, we investigated the applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Suitable MALDI matrices, including crystalline and ionic liquid matrices, were tested and the fragmentation of different AHL in collision-induced dissociation MS/MS was studied, providing information about characteristic marker fragments ions. Employing small-scale synthesis protocols, we established a versatile and cost-efficient procedure for fast generation of isotope-labeled AHL standards, which can be used without extensive purification and yielded accurate standard curves. Quantitative analysis was possible in the low pico-molar range, with lower limits of quantification reaching from 1 to 5 pmol for different AHL. The developed methodology was successfully applied in a quantitative MALDI MS analysis of low-volume culture supernatants of Pseudomonas aeruginosa. [Figure not available: see fulltext.

  4. Dissociative symptoms and dissociative disorders comorbidity in obsessive compulsive disorder: Symptom screening, diagnostic tools and reflections on treatment

    OpenAIRE

    Belli, Hasan

    2014-01-01

    Borderline personality disorder, conversion disorder and obsessive compulsive disorder frequently have dissociative symptoms. The literature has demonstrated that the level of dissociation might be correlated with the severity of obsessive compulsive disorder (OCD) and that those not responding to treatment had high dissociative symptoms. The structured clinical interview for DSM-IV dissociative disorders, dissociation questionnaire, somatoform dissociation questionnaire and dissociative expe...

  5. Dissociative symptoms and neuroendocrine dysregulation in depression.

    Science.gov (United States)

    Bob, Petr; Fedor-Freybergh, Peter; Jasova, Denisa; Bizik, Gustav; Susta, Marek; Pavlat, Josef; Zima, Tomas; Benakova, Hana; Raboch, Jiri

    2008-10-01

    Dissociative symptoms are traditionally attributed to psychological stressors that produce dissociated memories related to stressful life events. Dissociative disorders and dissociative symptoms including psychogenic amnesia, fugue, dissociative identity-disorder, depersonalization, derealization and other symptoms or syndromes have been reported as an epidemic psychiatric condition that may be coexistent with various psychiatric diagnoses such as depression, schizophrenia, borderline personality disorder or anxiety disorders. According to recent findings also the somatic components of dissociation may occur and influence brain, autonomic and neuroendocrine functions. At this time there are only few studies examining neuroendocrine response related to dissociative symptoms that suggest significant dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis. The aim of the present study is to perform examination of HPA axis functioning indexed by basal cortisol and prolactin and test their relationship to psychic and somatoform dissociative symptoms. Basal cortisol and prolactin and psychic and somatoform dissociative symptoms were assessed in 40 consecutive inpatients with diagnosis of unipolar depression mean age 43.37 (SD=12.21). The results show that prolactin and cortisol as indices of HPA axis functioning manifest significant relationship to dissociative symptoms. Main results represent highly significant correlations obtained by simple regression between psychic dissociative symptoms (DES) and serum prolactin (R=0.55, p=0.00027), and between somatoform dissociation (SDQ-20) and serum cortisol (R=-0.38, p=0.015). These results indicate relationship between HPA-axis reactivity and dissociative symptoms in unipolar depressive patients that could reflect passive coping behavior and disengagement.

  6. DISSOCIATIVE DISORDERS IN DSM-5

    NARCIS (Netherlands)

    Spiegel, David; Loewenstein, Richard J.; Lewis-Fernandez, Roberto; Sar, Vedat; Simeon, Daphne; Vermetten, Eric; Cardena, Etzel; Dell, Paul F.

    Background: We present recommendations for revision of the diagnostic criteria for the Dissociative Disorders (DDs) for DSM-5. The periodic revision of the DSM provides an opportunity to revisit the assumptions underlying specific diagnoses and the empirical support, or lack of it, for the defining

  7. Hydrogen dissociation on metal surfaces

    NARCIS (Netherlands)

    Wijzenbroek, M.

    2016-01-01

    Dissociative chemisorption is an important reaction step in many catalytic reactions. An example of such a reaction is the Haber-Bosch process, which is used commercially to produce ammonia, an important starting material in the production of fertilisers. In theoretical descriptions of such chemical

  8. Energy localization and molecular dissociation

    International Nuclear Information System (INIS)

    Takeno, S.; Tsironis, G.P.

    2005-01-01

    We study analytically as well as numerically the role that large-amplitude vibrations play during the process of molecular dissociation. Our model consists of a linear three-atom molecule composed of identical atoms interacting with their nearest neighbors by Morse potentials. We find a close relation between energy localization and bond breaking and evaluate numerically the corresponding reaction paths

  9. Dissociative electron attachment to the radiosensitizing chemotherapeutic agent hydroxyurea

    Energy Technology Data Exchange (ETDEWEB)

    Huber, S. E.; Tanzer, K.; Denifl, S. [Institute for Ion Physics and Applied Physics and Center of Molecular Biosciences Innsbruck, Leopold Franzens University of Innsbruck, Technikerstr. 25, 6020 Innsbruck (Austria); Śmiałek, M. A., E-mail: smialek@pg.gda.pl [Department of Control and Power Engineering, Faculty of Ocean Engineering and Ship Technology, Gdańsk University of Technology, Gabriela Narutowicza 11/12, 80-233 Gdańsk (Poland)

    2016-06-14

    Dissociative electron attachment to hydroxyurea was studied in the gas phase for electron energies ranging from zero to 9 eV in order to probe its radiosensitizing capabilities. The experiments were carried out using a hemispherical electron monochromator coupled with a quadrupole mass spectrometer. Diversified fragmentation of hydroxyurea was observed upon low energy electron attachment and here we highlight the major dissociation channels. Moreover, thermodynamic thresholds for various fragmentation reactions are reported to support the discussion of the experimental findings. The dominant dissociation channel, which was observed over a broad range of energies, is associated with formation of NCO{sup −}, water, and the amidogen (NH{sub 2}) radical. The second and third most dominant dissociation channels are associated with formation of NCNH{sup −} and NHCONH{sub 2}{sup −}, respectively, which are both directly related to formation of the highly reactive hydroxyl radical. Other ions observed with significant abundance in the mass spectra were NH{sub 2}{sup −}/O{sup −}, OH{sup −}, CN{sup −}, HNOH{sup −}, NCONH{sub 2}{sup −}, and ONHCONH{sub 2}{sup −}.

  10. Novel Antimicrobial Peptide Dendrimers with Amphiphilic Surface and Their Interactions with Phospholipids — Insights from Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Paulina Zielinska

    2013-06-01

    Full Text Available A series of new peptide dendrimers with amphiphilic surface, designed around a dendronized ornithine (Orn core were synthesized and characterized by ESI-MS, 1H-, 13C- NMR, and CD spectrometry. An improved antimicrobial potency against S. aureus and E. coli was detected as a result of an increased charge, higher branching and variable lipophilicity of the residues located at the C-terminus. Minimal inhibitory concentration (MIC values indicated that the selected dendrimers were not sensitive to the physiological concentration of Na+ and K+ ions (100 mM, but expressed reduced potency at 10 mM concentration of Mg2+ and Ca2+ ions. Circular dichroism (CD curves measured under various conditions revealed structure and solvent-dependent curve evolution. ESI-MS studies of gas-phase interactions between selected dendrimers and both anionic (DMPG and neutral (DMPC phospholipids revealed the presence of variously charged dendrimer/phospholipid aggregates with 1:1 to 1:5 stoichiometry. The collision-induced fragmentation (CID of the most abundant [dendrimer/phospholipid]2+ ions of the 1:1 stoichiometry demonstrated that the studied dendrimers formed stronger complexes with anionic DMPG. Both phospholipids have higher affinity towards dendrimers with a more compact structure. Higher differences in CID energy necessary for dissociation of 50% of the complex formed by dendrimers with DMPG vs. DMPC (DCID50 correlate with a lower hemotoxicity. Mass spectrometry results suggest that for a particular group of compounds the DCID50 might be one of the important factors explaining selectivity of antimicrobial peptides and their branched analogs targeting the bacterial membrane. Both circular dichroism and mass spectrometry studies demonstrated that dendrimers of Nα- and Nε-series possess a different conformation in solution and different affinity to model phospholipids, what might influence their specific microbicidal mechanism.

  11. InSourcerer: a high-throughput method to search for unknown metabolite modifications by mass spectrometry.

    Science.gov (United States)

    Mrzic, Aida; Lermyte, Frederik; Vu, Trung Nghia; Valkenborg, Dirk; Laukens, Kris

    2017-09-15

    Using mass spectrometry, the analysis of known metabolite structures has become feasible in a systematic high-throughput fashion. Nevertheless, the identification of previously unknown structures remains challenging, partially because many unidentified variants originate from known molecules that underwent unexpected modifications. Here, we present a method for the discovery of unknown metabolite modifications and conjugate metabolite isoforms in a high-throughput fashion. The method is based on user-controlled in-source fragmentation which is used to induce loss of weakly bound modifications. This is followed by the comparison of product ions from in-source fragmentation and collision-induced dissociation (CID). Diagonal MS 2 -MS 3 matching allows the detection of unknown metabolite modifications, as well as substructure similarities. As the method relies heavily on the advantages of in-source fragmentation and its ability to 'magically' elucidate unknown modification, we have named it inSourcerer as a portmanteau of in-source and sorcerer. The method was evaluated using a set of 15 different cytokinin standards. Product ions from in-source fragmentation and CID were compared. Hierarchical clustering revealed that good matches are due to the presence of common substructures. Plant leaf extract, spiked with a mix of all 15 standards, was used to demonstrate the method's ability to detect these standards in a complex mixture, as well as confidently identify compounds already present in the plant material. Here we present a method that incorporates a classic liquid chromatography/mass spectrometry (LC/MS) workflow with fragmentation models and computational algorithms. The assumptions upon which the concept of the method was built were shown to be valid and the method showed that in-source fragmentation can be used to pinpoint structural similarities and indicate the occurrence of a modification. Copyright © 2017 John Wiley & Sons, Ltd.

  12. Global functioning and disability in dissociative disorders.

    Science.gov (United States)

    Mueller-Pfeiffer, Christoph; Rufibach, Kaspar; Perron, Noelle; Wyss, Daniela; Kuenzler, Cornelia; Prezewowsky, Cornelia; Pitman, Roger K; Rufer, Michael

    2012-12-30

    Dissociative disorders are frequent comorbid conditions of other mental disorders. Yet, there is controversy about their clinical relevance, and little systematic research has been done on how they influence global functioning. Outpatients and day care patients (N=160) of several psychiatric units in Switzerland were assessed with the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV Axis I Disorders, Structured Clinical Interview for DSM-IV Dissociative Disorders, Global Assessment of Functioning Scale, and World Health Organization Disability Assessment Schedule-II. The association between subjects with a dissociative disorder (N=30) and functional impairment after accounting for non-dissociative axis I disorders was evaluated by linear regression models. We found a proportion of 18.8% dissociative disorders (dissociative amnesia=0%, dissociative fugue=0.6%, depersonalization disorder=4.4%, dissociative identity disorder=7.5%, dissociative disorder-not-otherwise-specified=6.3%) across treatment settings. Adjusted for other axis I disorders, subjects with a comorbid dissociative identity disorder or dissociative disorder-not-otherwise-specified had a median global assessment of functioning score that was 0.86 and 0.88 times, respectively, the score of subjects without a comorbid dissociative disorder. These findings support the hypothesis that complex dissociative disorders, i.e., dissociative identity disorder and dissociative disorder-not-otherwise-specified, contribute to functional impairment above and beyond the impact of co-existing non-dissociative axis I disorders, and that they qualify as "serious mental illness". Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  13. Dissociative Functions in the Normal Mourning Process.

    Science.gov (United States)

    Kauffman, Jeffrey

    1994-01-01

    Sees dissociative functions in mourning process as occurring in conjunction with integrative trends. Considers initial shock reaction in mourning as model of normal dissociation in mourning process. Dissociation is understood to be related to traumatic significance of death in human consciousness. Discerns four psychological categories of…

  14. Collision-induced absorption by D{sub 2} pairs in the first overtone band at 77, 201 and 298 K

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Kharma, M.; Gillard, P.G.; Reddy, S.P. [Memorial University of Newfoundland, Dept. of Physics and Physical Oceanography, Newfoundland (Canada)

    2006-01-15

    Collision induced absorption (CIA) spectra of pure D{sub 2} in the first overtone region from 5250 to 7250 cm{sup -1}, recorded at 77, 201 and 298 K, have been analyzed. The observed spectra at 77, 201 and 298 K were modelled by a total of 92, 214 and 267 components respectively of double vibrational transitions at room temperature of the type X{sub 2}(J) +X{sub 0}(J) and X{sub 1}(J) + X{sub 1}(J), where X is O, Q or S transitions. Profile analyses of the spectra were carried out using the Birnbaum-Cohen line-shape function for the individual components of the band, and characteristic line shape parameters were determined from the analysis. The observed and calculated profiles agree well over the whole overtone band, and the agreement is better than 97% in the three cases studied. Binary and ternary absorption coefficients were determined from the integrated absorption of the band. (authors)

  15. Infrared absorption spectra of gaseous HD. II. Collision-induced fundamental band of HD in HD--Ne and HD--Ar mixtures at room temperature

    International Nuclear Information System (INIS)

    Prasad, R.D.G.; Reddy, S.P.

    1976-01-01

    The collision-induced infrared absorption spectra of the fundamental band of HD in binary mixtures of HD with Ne and Ar at room temperature have been studied with an absorption path length of 105.2 cm for different base densities of HD in the range 8--20 amagat and a number of total gas densities up to 175 amagat. The observed features of the profiles of the enhancement of absorption in these mixtures resemble closely those of the corresponding profiles of the fundamental band of H 2 in binary mixtures with Ne and Ar. The binary absorption coefficients of the band obtained from the measured integrated intensities are (1.84 +- 0.06) x 10 -35 and (4.41 +- 0.06) x 10 -35 cm 6 s -1 for HD--Ne and HD--Ar, respectively. The characteristic half-width parameters, delta/subd/ and delta/subc/ of the overlap transitions and delta/subq/ (and delta/subq//sub prime/) of the quadrupolar transitions, are obtained from an analysis of the profiles of the enhancement of absorption in both these mixtures. The quantity delta/subc/ which is the half-width of the intercollisional interference dip of the Q branch increases with the density of the perturbing gas Ne or Ar, and for HD--Ne it varies in a manner similar to that for HD--He as described in Paper I of this series

  16. On the determination of double diffraction dissociation cross section at HERA

    International Nuclear Information System (INIS)

    Holtmann, H.; Nikolaev, N.N.; Speth, J.; Zakharov, B.G.

    1996-01-01

    The excitation of the proton into undetected multiparticle states (double diffraction dissociation) is an important background to single diffractive deep-inelastic processes ep→e'p'ρ 0 , e'p'J/Ψ, e'p'X at HERA. We present estimates of the admixture of the double diffraction dissociation events in all diffractive events. We find that in the J/Ψ photoproduction, electroproduction of the ρ 0 at large Q 2 and diffraction dissociation of real and virtual photons into high mass states X the contamination of the double diffraction dissociation can be as large as ∼30%, thus affecting substantially the experimental tests of the pomeron exchange in deep inelastic scattering at HERA. We discuss a possibility of tagging the double diffraction dissociation by neutrons observed in the forward neutron calorimeter. We present evaluations of the spectra of neutrons and efficiency of neutron tagging based on the experimental data for diffractive processes in the proton-proton collisions. (orig.)

  17. Radiative capture versus Coulomb dissociation

    International Nuclear Information System (INIS)

    Esbensen, H.; Physics

    2006-01-01

    Measurements of the Coulomb dissociation of 8 B have been used to infer the rate of the inverse radiative proton capture on 7 Be. The analysis is usually based on the assumptions that the two processes are related by detailed balance and described by E1 transitions. However, there are corrections to this relation. The Coulomb form factors for the two processes, for example, are not identical. There are also E2 transitions and higher-order effects in the Coulomb dissociation, and the nuclear induced breakup cannot always be ignored. While adding first-order E2 transitions enhances the decay energy spectrum, the other mechanisms cause a suppression at low relative energies. The net result may accidentally be close to the conventional first-order E1 calculation, but there are differences which cannot be ignored if accuracies of 10% or better are needed

  18. Radiative Capture versus Coulomb Dissociation

    International Nuclear Information System (INIS)

    Esbensen, Henning

    2006-01-01

    Measurements of the Coulomb dissociation of 8B have been used to infer the rate of the inverse radiative proton capture on 7Be. The analysis is usually based on the assumptions that the two processes are related by detailed balance and described by E1 transitions. However, there are corrections to this relation. The Coulomb form factors for the two processes, for example, are not identical. There are also E2 transitions and higher-order effects in the Coulomb dissociation, and the nuclear induced breakup cannot always be ignored. While adding first-order E2 transitions enhances the decay energy spectrum, the other mechanisms cause a suppression at low relative energies. The net result may accidentally be close to the conventional first-order E1 calculation, but there are differences which cannot be ignored if accuracies of 10% or better are needed

  19. Production of Hydrated Metal Ions by Fast Ion or Atom Beam Sputtering. Collision-Induced Dissociation and Successive Hydration Energies of Gaseous Cu+ with 1-4 Water Molecules

    NARCIS (Netherlands)

    Magnera, Thomas F.; David, Donald E.; Stulik, Dusan; Orth, Robert G.; Jonkman, Harry T.; Michl, Josef

    1989-01-01

    Low-temperature sputtering of frozen aqueous solutions of metal salts, of hydrated crystalline transition-metal salts, of frosted metal surfaces, and of frosted metal salts with kiloelectronvolt energy rare gas atoms or ions produces copious amounts of cluster ions, among which M+(H2O)n and/or

  20. Development and optimization of an UPLC-QTOF-MS/MS method based on an in-source collision induced dissociation approach for comprehensive discrimination of chlorogenic acids isomers from Momordica plant species

    CSIR Research Space (South Africa)

    Madala, NE

    2014-09-01

    Full Text Available is by their differential retention time during a chromatographic separation. In a reverse chromatography, the cis-3-acyl and cis-4-acyl molecules elute before their Hindawi Publishing Corporation Journal of Analytical Methods in Chemistry Volume 2014, Article ID 650879, 7... pages http://dx.doi.org/10.1155/2014/650879 2 Journal of Analytical Methods in Chemistry trans counterparts whilst the opposite is the case for 5-acyl molecule [4]. It is indeed clear that the CGA molecules offer a very interesting analytical challenge...

  1. Analyses of chlorogenic acids and related cinnamic acid derivatives from Nicotiana tabacum tissues with the aid of UPLC-QTOF-MS/MS based on the in-source collision-induced dissociation method

    CSIR Research Space (South Africa)

    Ncube, EN

    2014-11-01

    Full Text Available of chlorogenic ac t F d A to quinic acids. These compounds are present in almost all plants and contribute a significant fraction of the total acid (FQA), respectively [1,2]. Other acids such as sinapic acids are, however, rarely found. Ncube et al. Chemistry... circles using a vacuum filtration system (Millipore, Billerica, MA, USA) and washed with 20 mL MS medium without vitamins while tobacco leaves were ground with a mortar and pestle in liquid nitrogen. Two grams (2 g) of each sample was weighed and homoge...

  2. Hydrogen dissociation on metal surfaces

    OpenAIRE

    Wijzenbroek, M.

    2016-01-01

    Dissociative chemisorption is an important reaction step in many catalytic reactions. An example of such a reaction is the Haber-Bosch process, which is used commercially to produce ammonia, an important starting material in the production of fertilisers. In theoretical descriptions of such chemical processes often approximations need to be made in order to keep the computational cost feasible, such as fixing the surface atoms in place, rather than allowing them to vibrate. In this work, seve...

  3. Diffraction dissociation and elastic scattering

    International Nuclear Information System (INIS)

    Verebryusov, V.S.; Ponomarev, L.A.; Smorodinskaya, N.Ya.

    1987-01-01

    In the framework of Regge scheme with supercritical pomeron a model is suggested for the NN-scattering amplitude which takes into account the contribution introduced to the intermediate state by diffraction dissociation (DD) processes. The DD amplitude is written in terms of the Deck model which has been previously applied to describing the main DD features. The calculated NN cross sections are compared with those obtained experimentally. Theoretical predictions for higher energy are presented

  4. Dissociative Photoionization of Diethyl Ether.

    Science.gov (United States)

    Voronova, Krisztina; Mozaffari Easter, Chrissa M; Covert, Kyle J; Bodi, Andras; Hemberger, Patrick; Sztáray, Bálint

    2015-10-29

    The dissociative photoionization of internal energy selected diethyl ether ions was investigated by imaging photoelectron photoion coincidence spectroscopy. In a large, 5 eV energy range Et2O(+) cations decay by two parallel and three sequential dissociative photoionization channels, which can be modeled well using statistical theory. The 0 K appearance energies of the CH3CHOCH2CH3(+) (H-loss, m/z = 73) and CH3CH2O═CH2(+) (methyl-loss, m/z = 59) fragment ions were determined to be 10.419 ± 0.015 and 10.484 ± 0.008 eV, respectively. The reemergence of the hydrogen-loss ion above 11 eV is attributed to transition-state (TS) switching, in which the second, outer TS is rate-determining at high internal energies. At 11.81 ± 0.05 eV, a secondary fragment of the CH3CHOCH2CH3(+) (m/z = 73) ion, protonated acetaldehyde, CH3CH═OH(+) (m/z = 45) appears. On the basis of the known thermochemical onset of this fragment, a reverse barrier of 325 meV was found. Two more sequential dissociation reactions were examined, namely, ethylene and formaldehyde losses from the methyl-loss daughter ion. The 0 K appearance energies of 11.85 ± 0.07 and 12.20 ± 0.08 eV, respectively, indicate no reverse barrier in these processes. The statistical model of the dissociative photoionization can also be used to predict the fractional ion abundances in threshold photoionization at large temperatures, which could be of use in, for example, combustion diagnostics.

  5. Autonoesis and dissociative identity disorder.

    Science.gov (United States)

    Morton, John

    2018-01-01

    Dissociative identity disorder is characterised by the presence in one individual of two or more alternative personality states (alters). For such individuals, the memory representation of a particular event can have full episodic, autonoetic status for one alter, while having the status of knowledge or even being inaccessible to a second alter. This phenomenon appears to create difficulties for a purely representational theory and is presented to Mahr & Csibra (M&C) for their consideration.

  6. [Clinical Handling of Patients with Dissociative Disorders].

    Science.gov (United States)

    Okano, Kenichiro

    2015-01-01

    This paper discusses the way informed psychiatrists are expected to handle dissociative patients in clinical situations, with a specific focus on dissociative identity disorders and dissociative fugue. On the initial interview with dissociative patients, information on their history of trauma and any nascent dissociative symptoms in their childhood should be carefully obtained. Their level of stress in their current life should also be assessed in order to understand their symptomatology, as well as to predict their future clinical course. A psychoeducational approach is crucial; it might be helpful to give information on dissociative disorder to these patients as well as their family members in order to promote their adherence to treatment. Regarding the symptomatology of dissociative disorders, detailed symptoms and the general clinical course are presented. It was stressed that dissociative identity disorder and dissociative fugue, the most high-profile dissociative disorders, are essentially different in their etiology and clinical presentation. Dissociative disorders are often confused with and misdiagnosed as psychotic disorders, such as schizophrenia. Other conditions considered in terms of the differential diagnosis include borderline personality disorder as well as temporal lobe epilepsy. Lastly, the therapeutic approach to dissociative identity disorder is discussed. Each dissociative identity should be understood as potentially representing some traumatically stressful event in the past. The therapist should be careful not to excessively promote the creation or elaboration of any dissociative identities. Three stages are proposed in the individual psychotherapeutic process. In the initial stage, a secure environment and stabilization of symptoms should be sought. The second stage consists of aiding the "host" personality to make use of other more adaptive coping skills in their life. The third stage involves coaching as well as continuous awareness of

  7. Photoionization and dissociative photoionization study of HFC-152a using synchrotron radiation

    International Nuclear Information System (INIS)

    Huang Chaoqun; Wei Lixia; Yang Bin; Yang Rui; Wang Sisheng; Shan Xiaobin; Qi Fei; Zhang Yunwu; Sheng Liusi; Hao Liqing; Zhou Shikang; Wang Zhenya

    2006-01-01

    Photoionization and dissociative photoionization of HFC-152a have been studied using synchrotron radiation and a reflection time-of-flight mass spectrometry (RTOF-MS). The ionization energy of parent molecule (11.94 ± 0.04 eV) and appearance potentials of various fragment ions have been determined by measuring their photoionization efficiency curves. Energies, symmetry point groups and ground electronic states of neutrals and cations of parent and its fragments have been calculated using GAUSSIAN-03 program with the G3 method. According to the theoretical and experimental results, some dissociation channels and their dissociation energies of CH 3 CHF 2 + have been analyzed. (authors)

  8. Lifetime and kinetic energy release of metastable dications dissociation

    International Nuclear Information System (INIS)

    Alagia, M.; Candori, P.; Falcinelli, S.; Mundim, K.C.; Mundim, M.S.P.; Pirani, F.; Richter, R.; Stranges, S.; Vecchiocattivi, F.

    2012-01-01

    Graphical abstract: A statistical method is proposed for extracting dynamics information from coincidence data in double photoionization of molecules. Highlights: ► When a photon, with sufficient energy, hits a molecule, a doubly charged ion can be formed. This dication has often a large probability of dissociate in two positive singly charged ions. ► Experiments of photoelectron–photoion–photoion coincidence can provide valuable information about the dynamics of such dissociation processes. ► A statistical method is proposed for extracting such information from the coincidence data. - Abstract: A new method for the determination of dynamical features of the molecular dication dissociation processes, following the single photon double ionization, investigated by time-of-flight mass spectrometry technique has been developed. The method is based on an extension of the generalized simulated annealing statistical methodology, previously applied in other fields. Here it is described and applied, as an example, to the case of the dissociation of the CO 2 2+ dication giving CO + + O + ion fragments. The results are consistent with previous determination of the metastable lifetime of the dication, but the analysis also provides additional information about the dynamics of the reaction.

  9. Feasibility of large-scale phosphoproteomics with higher energy collisional dissociation fragmentation

    DEFF Research Database (Denmark)

    Nagaraj, Nagarjuna; D'Souza, Rochelle C J; Cox, Juergen

    2010-01-01

    Mass spectrometry (MS)-based proteomics now enables the analysis of thousands of phosphorylation sites in single projects. Among a wide range of analytical approaches, the combination of high resolution MS scans in an Orbitrap analyzer with low resolution MS/MS scans in a linear ion trap has proven......-scale phosphoproteome analysis alongside collisional induced dissociation, (CID) and electron capture/transfer dissociation (ECD/ETD)....

  10. 声致发光气泡中原子碰撞发光机制%Collision induced radiation in sonoluminescing bubble

    Institute of Scientific and Technical Information of China (English)

    安宇; 谢崇国

    2001-01-01

    We educe a probability of the electric quadrupole emission of a photon induced by collision between two neutral atoms of inert gases. For heat equilibrium system of inert gas, we deduce the formula of the collision-induced total radiation power per unit volume, per unit wavelength at the given wavelength. Considering the absorption of the gas and refraction of surrounding water, the formula apply to fit the experimental spetra of sonoluminescent pure xenon and pure krypton bubbles, the fits are shown to be quite well correspond to temperature about 5,000K. The good agreement obtained demonstrate the new light-emitting mechanism of sonoluminescence of xenon and krypton bubble.%文章导出一种由两个中性的惰性气体原子之间的碰撞引起的电四极辐射几率。对于热平衡的惰性气体系统,推导出由碰撞引起的总辐射能量的公式(单位体积,在给定波长的每单位波长)。考虑到气体的吸收和周围环境水的折射,用此公式拟合纯氙和纯氪的单气泡声致发光的实验光谱,拟合温度大约为 5,000k,结果令人满意。

  11. Distinguishing Aspartic and Isoaspartic Acids in Peptides by Several Mass Spectrometric Fragmentation Methods

    Science.gov (United States)

    DeGraan-Weber, Nick; Zhang, Jun; Reilly, James P.

    2016-12-01

    Six ion fragmentation techniques that can distinguish aspartic acid from its isomer, isoaspartic acid, were compared. MALDI post-source decay (PSD), MALDI 157 nm photodissociation, tris(2,4,6-trimethoxyphenyl)phosphonium bromide (TMPP) charge tagging in PSD and photodissociation, ESI collision-induced dissociation (CID), electron transfer dissociation (ETD), and free-radical initiated peptide sequencing (FRIPS) with CID were applied to peptides containing either aspartic or isoaspartic acid. Diagnostic ions, such as the y-46 and b+H2O, are present in PSD, photodissociation, and charge tagging. c•+57 and z-57 ions are observed in ETD and FRIPS experiments. For some molecules, aspartic and isoaspartic acid yield ion fragments with significantly different intensities. ETD and charge tagging appear to be most effective at distinguishing these residues.

  12. Photon diffractive dissociation in deep inelastic scattering

    International Nuclear Information System (INIS)

    Wuesthoff, M.

    1995-09-01

    The cross section of the Photon Diffractive Dissociation in Deep Inelastic Scattering is calculated in the frame work of perturbative QCD. In the triple Regge region the BFKL-approximation is used to evaluate the leading contributions of the corresponding Feynman diagrams with a subsequent resummation in terms of integral equations. These equations are partly solved leading to an effective two to four gluons transition vertex. This exhibits remarkable properties like the total symmetry under the interchange of gluons, the conformal invariance and a simple colour structure. The presence of four interacting gluons in the t-channel does not support the simple triple Pomeron picture with solely a local vertex. A dimensional conservation law is found for zero momentum transfer with the consequence that a direct coupling of the three BFKL-singularities is absent. Another consequence is the dominance of small transverse momenta at the triple Pomeron vertex. Beyond the triple Regge limit a slightly different approach is used in which the diagrams are calculated with leading log(Q 2 ) accuracy. Higher twist contributions are neglected except for the longitudinal part of the cross section which dominates at small invariant masses M in accordance with QCD-predictions and measurements for the exclusive production of vector mesons. For the comparison with the recently measured Photon Diffractive Dissociation-data from H1 and ZEUS a model for the Pomeron is introduced based on the F 2 -data. In the spirit of the k t -factorization theorem this model is inserted in place of the BFKL-Pomeron. Considering the fact that this approach does not contain free parameters the agreement between the theoretical prediction and the data is found to be good. (orig.)

  13. Characterization of Nα-Fmoc-protected dipeptide isomers by electrospray ionization tandem mass spectrometry (ESI-MS(n)): effect of protecting group on fragmentation of dipeptides.

    Science.gov (United States)

    Ramesh, M; Raju, B; Srinivas, R; Sureshbabu, V V; Vishwanatha, T M; Hemantha, H P

    2011-07-30

    A series of positional isomeric pairs of Fmoc-protected dipeptides, Fmoc-Gly-Xxx-OY/Fmoc-Xxx-Gly-OY (Xxx=Ala, Val, Leu, Phe) and Fmoc-Ala-Xxx-OY/Fmoc-Xxx-Ala-OY (Xxx=Leu, Phe) (Fmoc=[(9-fluorenylmethyl)oxy]carbonyl) and Y=CH(3)/H), have been characterized and differentiated by both positive and negative ion electrospray ionization ion-trap tandem mass spectrometry (ESI-IT-MS(n)). In contrast to the behavior of reported unprotected dipeptide isomers which mainly produce y(1)(+) and/or a(1)(+) ions, the protonated Fmoc-Xxx-Gly-OY, Fmoc-Ala-Xxx-OY and Fmoc-Xxx-Ala-OY yield significant b(1)(+) ions. These ions are formed, presumably with stable protonated aziridinone structures. However, the peptides with Gly- at the N-terminus do not form b(1)(+) ions. The [M+H](+) ions of all the peptides undergo a McLafferty-type rearrangement followed by loss of CO(2) to form [M+H-Fmoc+H](+). The MS(3) collision-induced dissociation (CID) of these ions helps distinguish the pairs of isomeric dipeptides studied in this work. Further, negative ion MS(3) CID has also been found to be useful for differentiating these isomeric peptide acids. The MS(3) of [M-H-Fmoc+H](-) of isomeric peptide acids produce c(1)(-), z(1)(-) and y(1)(-) ions. Thus the present study of Fmoc-protected peptides provides additional information on mass spectral characterization of the dipeptides and distinguishes the positional isomers. Copyright © 2011 John Wiley & Sons, Ltd.

  14. Simple setup for gas-phase h/d exchange mass spectrometry coupled to electron transfer dissociation and ion mobility for analysis of polypeptide structure on a liquid chromatographic time scale

    DEFF Research Database (Denmark)

    Mistarz, Ulrik Hvid; Brown, Jeffery M; Haselmann, Kim F

    2014-01-01

    gas immediately upstream or downstream of the primary skimmer cone. The approach was implemented on three commercially available mass spectrometers and required no or minor fully reversible reconfiguration of gas-inlets of the ion source. Results from gas-phase HDX-MS of peptides using the aqueous ND3....../D2O as HDX reagent indicate that labeling is facilitated exclusively through gaseous ND3, yielding similar results to the infusion of purified ND3-gas, while circumventing the complications associated with the use of hazardous purified gases. Comparison of the solution-phase- and gas-phase deuterium...

  15. Experimentally-induced dissociation impairs visual memory.

    Science.gov (United States)

    Brewin, Chris R; Mersaditabari, Niloufar

    2013-12-01

    Dissociation is a phenomenon common in a number of psychological disorders and has been frequently suggested to impair memory for traumatic events. In this study we explored the effects of dissociation on visual memory. A dissociative state was induced experimentally using a mirror-gazing task and its short-term effects on memory performance were investigated. Sixty healthy individuals took part in the experiment. Induced dissociation impaired visual memory performance relative to a control condition; however, the degree of dissociation was not associated with lower memory scores in the experimental group. The results have theoretical and practical implications for individuals who experience frequent dissociative states such as patients with posttraumatic stress disorder (PTSD). Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Studies of neutron dissociation at FermiLab energies

    International Nuclear Information System (INIS)

    Ferbel, T.

    1975-01-01

    The characteristics of diffraction dissociation of neutrons into pπ - systems at high energies were examined. A substantial correlation is observed between the mass and the t of the produced system. The spin structure of the pπ - amplitudes at low mass is very complex, but is described surprisingly well by the simple Deck Mechanism. Both π-exchange and proton-exchange contributions are evident in diffractive production. The t-channel and s-channel helicity amplitudes contain comparable contributions from flip and nonflip terms and the produced states are not restricted to those expected on the basis of the Morrison rule

  17. Diffractive dissociation and new quarks

    International Nuclear Information System (INIS)

    White, A.R.

    1983-04-01

    We argue that the chiral limit of QCD can be identified with the strong (diffractive dissociation) coupling limit of reggeon field theory. Critical Pomeron scaling at high energy must then be directly related to an infra-red fixed-point of massless QCD and so requires a large number of flavors. This gives a direct argument that the emergence of diffraction-peak scaling, KNO scaling etc. at anti p-p colliders are evidence of a substantial quark structure still to be discovered

  18. [Characteristics of Bacillus cereus dissociants].

    Science.gov (United States)

    Doroshenko, E V; Loĭko, N G; Il'inskaia, O N; Kolpakov, A I; Gornova, I B; Klimanova, E V; El'-Registan, G I

    2001-01-01

    The autoregulation of the phenotypic (populational) variability of the Bacillus cereus strain 504 was studied. The isolated colonial morphotypes of this bacterium were found to differ in their growth characteristics and the synthesis of extracellular proteases. The phenotypic variabilities of vegetative proliferating cells and those germinated from endospores and cystlike refractory cells were different. Bacterial variants also differed in the production of the d1 and d2 factors (the autoinducers of dormancy and autolysis, respectively) and sensitivity to them. The possible role of these factors in the dissociation of microorganisms is discussed.

  19. Mirror Writing and a Dissociative Identity Disorder

    OpenAIRE

    Le, Catherine; Smith, Joyce; Cohen, Lewis

    2009-01-01

    Individuals with dissociative identity disorder (DID) have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam—mirror writing. It is not known whether her mirror...

  20. Simultaneous detection and identification of precursors, degradation and co-products of chemical warfare agents in drinking water by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Tak, Vijay; Purohit, Ajay; Pardasani, Deepak; Goud, D Raghavender; Jain, Rajeev; Dubey, D K

    2014-11-28

    Environmental markers of chemical warfare agents (CWAs) comprise millions of chemical structures. The simultaneous detection and identification of these environmental markers poses difficulty due to their diverse chemical properties. In this work, by using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF), a generic analytical method for the detection and identification of wide range of environmental markers of CWAs (including precursors, degradation and co-products of nerve agents and sesqui-mustards) in drinking water, was developed. The chromatographic analysis of 55 environmental markers of CWAs including isomeric and isobaric compounds was accomplished within 20 min, using 1.8 μm particle size column. Subsequent identification of the compounds was achieved by the accurate mass measurement of either protonated molecule [M+H](+) or ammonium adduct [M+NH4](+) and fragment ions. Isomeric and isobaric compounds were distinguished by chromatographic retention time, characteristic fragment ions generated by both in-source collision induced dissociation (CID) and CID in the collision cell by MS/MS experiments. The exact mass measurement errors for all ions were observed less than 3 ppm with internal calibration. The method limits of detection (LODs) and limits of quantification (LOQs) were determined in drinking water and found to be 1-50 ng mL(-1) and 5-125 ng mL(-1), respectively. Applicability of the proposed method was proved by determining the environmental markers of CWAs in aqueous samples provided by Organization for the Prohibition of Chemical Weapons during 34th official proficiency test. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Activation of CH4 by Th(+) as studied by guided ion beam mass spectrometry and quantum chemistry.

    Science.gov (United States)

    Cox, Richard M; Armentrout, P B; de Jong, Wibe A

    2015-04-06

    The reaction of atomic thorium cations with CH4 (CD4) and the collision-induced dissociation (CID) of ThCH4(+) with Xe are studied using guided ion beam tandem mass spectrometry. In the methane reactions at low energies, ThCH2(+) (ThCD2(+)) is the only product; however, the energy dependence of the cross-section is inconsistent with a barrierless exothermic reaction as previously assumed on the basis of ion cyclotron resonance mass spectrometry results. The dominant product at higher energies is ThH(+) (ThD(+)), with ThCH3(+) (ThCD3(+)) having a similar threshold energy. The latter product subsequently decomposes at still higher energies to ThCH(+) (ThCD(+)). CID of ThCH4(+) yields atomic Th(+) as the exclusive product. The cross-sections of all product ions are modeled to provide 0 K bond dissociation energies (in eV) of D0(Th(+)-H) ≥ 2.25 ± 0.18, D0(Th(+)-CH) = 6.19 ± 0.16, D0(Th(+)-CH2) ≥ 4.54 ± 0.09, D0(Th(+)-CH3) = 2.60 ± 0.30, and D0(Th(+)-CH4) = 0.47 ± 0.05. Quantum chemical calculations at several levels of theory are used to explore the potential energy surfaces for activation of methane by Th(+), and the effects of spin-orbit coupling are carefully considered. When spin-orbit coupling is explicitly considered, a barrier for C-H bond activation that is consistent with the threshold measured for ThCH2(+) formation (0.17 ± 0.02 eV) is found at all levels of theory, whereas this barrier is observed only at the BHLYP and CCSD(T) levels otherwise. The observation that the CID of the ThCH4(+) complex produces Th(+) as the only product with a threshold of 0.47 eV indicates that this species has a Th(+)(CH4) structure, which is also consistent with a barrier for C-H bond activation. This barrier is thought to exist as a result of the mixed ((4)F,(2)D) electronic character of the Th(+) J = (3)/2 ground level combined with extensive spin-orbit effects.

  2. Mirror Writing and a Dissociative Identity Disorder

    Directory of Open Access Journals (Sweden)

    Catherine Le

    2009-01-01

    Full Text Available Individuals with dissociative identity disorder (DID have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam—mirror writing. It is not known whether her mirror writing had a deeper level of meaning; however, it does emphasize the idiosyncratic nature of dissociative identity disorder.

  3. Mirror writing and a dissociative identity disorder.

    Science.gov (United States)

    Le, Catherine; Smith, Joyce; Cohen, Lewis

    2009-01-01

    Individuals with dissociative identity disorder (DID) have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam-mirror writing. It is not known whether her mirror writing had a deeper level of meaning; however, it does emphasize the idiosyncratic nature of dissociative identity disorder.

  4. Electron scattering resonances and dissociative attachment in polyatomic molecules

    International Nuclear Information System (INIS)

    Olthoff, J.K.

    1985-01-01

    A relatively new technique, electron transmission spectroscopic, is now being used to investigate the unoccupied valence molecular orbitals of many chemical compounds. Electron-transmission spectroscopy measures the energy of negative ion states that arise from electron capture into unoccupied molecular orbitals. Additional information about the unoccupied orbitals may be obtained if the negative ion decays by way of dissociation. Determination of the identity, kinetic energy, and production rates of stable ion fragments supplies information about the shape and position of the potential energy curves which describe the electronic states of the molecule and the anion. Used together, photoelectron, electron transmission, and dissociation data can produce a complete picture of a molecule's valence electronic structure. For this work, a time-of-flight mass spectrometer was attached to an electron transmission spectrometer to observe negative ion fragments due to dissociative attachment. The mass spectrometer measures the identify and kinetic energy of stable negative ions as a function of incident electron energy. Electron transmission spectra and ion production data were acquired for many compounds in four chemical categories

  5. Dissociative symptoms and dissociative disorder comorbidity in patients with obsessive-compulsive disorder.

    Science.gov (United States)

    Belli, Hasan; Ural, Cenk; Vardar, Melek Kanarya; Yesılyurt, Sema; Oncu, Fatıh

    2012-10-01

    The present study attempted to assess the dissociative symptoms and overall dissociative disorder comorbidity in patients with obsessive-compulsive disorder (OCD). In addition, we examined the relationship between the severity of obsessive-compulsive symptoms and dissociative symptoms. All patients admitted for the first time to the psychiatric outpatient unit were included in the study. Seventy-eight patients had been diagnosed as having OCD during the 2-year study period. Patients had to meet the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for OCD. Most (76.9%; n = 60) of the patients were female, and 23.1% (n = 18) of the patients were male. Dissociation Questionnaire was used to measure dissociative symptoms. The Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Dissociative Disorders interviews and Yale-Brown Obsessive Compulsive Checklist and Severity Scale were used. Eleven (14%) of the patients with OCD had comorbid dissociative disorder. The most prevalent disorder in our study was dissociative depersonalization disorder. Dissociative amnesia and dissociative identity disorder were common as well. The mean Yale-Brown score was 23.37 ± 7.27 points. Dissociation Questionnaire scores were between 0.40 and 3.87 points, and the mean was 2.23 ± 0.76 points. There was a statistically significant positive correlation between Yale-Brown points and Dissociation Questionnaire points. We conclude that dissociative symptoms among patients with OCD should alert clinicians for the presence of a chronic and complex dissociative disorder. Clinicians may overlook an underlying dissociative process in patients who have severe symptoms of OCD. However, a lack of adequate response to cognitive-behavioral and drug therapy may be a consequence of dissociative process. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Dissociative identity disorder: Medicolegal challenges.

    Science.gov (United States)

    Farrell, Helen M

    2011-01-01

    Persons with dissociative identity disorder (DID) often present in the criminal justice system rather than the mental health system and perplex experts in both professions. DID is a controversial diagnosis with important medicolegal implications. Defendants have claimed that they committed serious crimes, including rape or murder, while they were in a dissociated state. Asserting that their alter personality committed the bad act, defendants have pleaded not guilty by reason of insanity (NGRI). In such instances, forensic experts are asked to assess the defendant for DID and provide testimony in court. Debate continues over whether DID truly exists, whether expert testimony should be allowed into evidence, and whether it should exculpate defendants for their criminal acts. This article reviews historical and theoretical perspectives on DID, presents cases that illustrate the legal implications and controversies of raising an insanity defense based on multiple personalities, and examines the role of forensic experts asked to comment on DID with the goal of assisting clinicians in the medicolegal assessment of DID in relation to crimes.

  7. Experimental study of the dissociation of 100-600 KeV hydrogen cluster ions in an argon gas target

    International Nuclear Information System (INIS)

    Chevallier, M.; Clouvas, A.; Frischkorn, H.J.; Gaillard, M.J.; Poizat, J.C.; Remillieux, J.

    1985-09-01

    We have studied the break-up of accelerated hydrogen cluster ions passing through an argon gas target. The absolute dissociation cross section has been measured for a wide variety of H n + (odd masses only) cluster ions, with n between 5 and 23 and with projectile velocities ranging from 1.5 to 5 x 10 8 cm/s. We discuss the dissociation processes and the dependence of their cross-sections upon the cluster mass and velocity

  8. Cross Sections for Electron-Impact Dissociation of Alternative Etching Gas, C3HF7O

    Science.gov (United States)

    Tanaka, Hideyuki; Toyoda, Hirotaka; Sugai, Hideo

    1998-09-01

    The search for alternative for perfluorocarbon gases from the environmental point of view has resulted in a new etching gas, C3HF7O (1,2,2,2-tetrafluoroethyl-trifluoromethyl ether, abbreviated as HFE-227). In this paper, the first measurement of the absolute cross sections for the dissociation of HFE-227, is reported.The neutral dissociation is measured from the threshold to 250 eV by appearance mass spectrometry in a dual electron beam device.The threshold energies for the neutral dissociation into CF, CF2 and CF3 are 14.7, 12.5 and 11.2 eV, respectively.The cross sections for the dissociation from HFE-227 into CF3 and CF are larger than those from c-C4F8 (octafluorocyclobutane), but not for the dissociation into CF2.Besides the neutral dissociation, the cross sections for the dissociative ionization of HFE-227 are extensively measured for the formation of twelve ionic species, i.e., CO+, CHO+, CF+, CHF+, CFO+, CF2+, CHF2+, CF3+, CHF3+, C2HF2O+, C2HF4+ and C2HF4O+.

  9. Electron Detachment Dissociation (EDD) of Fluorescently Labeled Sialylated Oligosaccharides

    Science.gov (United States)

    Zhou, Wen; Håkansson, Kristina

    2012-01-01

    We explored the application of electron detachment dissociation (EDD) and infrared multiphoton dissociation (IRMPD) tandem mass spectrometry to fluorescently labeled sialylated oligosaccharides. Standard sialylated oligosaccharides and a sialylated N-linked glycan released from human transferrin were investigated. EDD yielded extensive glycosidic cleavages and cross-ring cleavages in all cases studied, consistently providing complementary structural information compared to IRMPD. Neutral losses and satellite ions such as C – 2H ions were also observed following EDD. In addition, we examined the influence of different fluorescent labels. The acidic label 2-aminobenzoic acid (2-AA) enhanced signal abundance in negative-ion mode. However, few cross-ring fragments were observed for 2-AA labeled oligosaccharides. The neutral label 2-aminobenzamide (2-AB) resulted in more cross-ring cleavages compared to 2-AA labeled species, but not as extensive fragmentation as for native oligosaccharides, likely resulting from altered negative charge locations from introduction of the fluorescent tag. PMID:22120881

  10. From dissociation to trauma? Individual differences in dissociation as predictor of 'trauma' perception

    NARCIS (Netherlands)

    Rassin, Eric; van Rootselaar, Anne-Fleur

    2006-01-01

    In clinical literature, dissociative complaints are generally considered to be the result of traumatic experiences. However, it has been argued that dissociative complaints, in turn, may indulge over-reporting of traumatic experiences. Hence, correlations between dissociation and self-reported

  11. Dissociation in patients with dissociative seizures: relationships with trauma and seizure symptoms.

    Science.gov (United States)

    Pick, S; Mellers, J D C; Goldstein, L H

    2017-05-01

    This study aimed to extend the current understanding of dissociative symptoms experienced by patients with dissociative (psychogenic, non-epileptic) seizures (DS), including psychological and somatoform types of symptomatology. An additional aim was to assess possible relationships between dissociation, traumatic experiences, post-traumatic symptoms and seizure manifestations in this group. A total of 40 patients with DS were compared with a healthy control group (n = 43), matched on relevant demographic characteristics. Participants completed several self-report questionnaires, including the Multiscale Dissociation Inventory (MDI), Somatoform Dissociation Questionnaire-20, Traumatic Experiences Checklist and the Post-Traumatic Diagnostic Scale. Measures of seizure symptoms and current emotional distress (Hospital Anxiety and Depression Scale) were also administered. The clinical group reported significantly more psychological and somatoform dissociative symptoms, trauma, perceived impact of trauma, and post-traumatic symptoms than controls. Some dissociative symptoms (i.e. MDI disengagement, MDI depersonalization, MDI derealization, MDI memory disturbance, and somatoform dissociation scores) were elevated even after controlling for emotional distress; MDI depersonalization scores correlated positively with trauma scores while seizure symptoms correlated with MDI depersonalization, derealization and identity dissociation scores. Exploratory analyses indicated that somatoform dissociation specifically mediated the relationship between reported sexual abuse and DS diagnosis, along with depressive symptoms. A range of psychological and somatoform dissociative symptoms, traumatic experiences and post-traumatic symptoms are elevated in patients with DS relative to healthy controls, and seem related to seizure manifestations. Further studies are needed to explore peri-ictal dissociative experiences in more detail.

  12. Absolute total and partial dissociative cross sections of pyrimidine at electron and proton intermediate impact velocities

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, Wania, E-mail: wania@if.ufrj.br; Luna, Hugo; Sigaud, Lucas; Montenegro, Eduardo C. [Instituto de Física, Universidade Federal do Rio de Janeiro, PO 68528, 21941-972 Rio de Janeiro, RJ (Brazil); Tavares, Andre C. [Departamento de Física, Pontificia Universidade Católica do Rio de Janeiro, PO 38071, Rua Marquês de São Vicente 225, 22453-900 Rio de Janeiro, RJ (Brazil)

    2014-02-14

    Absolute total non-dissociative and partial dissociative cross sections of pyrimidine were measured for electron impact energies ranging from 70 to 400 eV and for proton impact energies from 125 up to 2500 keV. MOs ionization induced by coulomb interaction were studied by measuring both ionization and partial dissociative cross sections through time of flight mass spectrometry and by obtaining the branching ratios for fragment formation via a model calculation based on the Born approximation. The partial yields and the absolute cross sections measured as a function of the energy combined with the model calculation proved to be a useful tool to determine the vacancy population of the valence MOs from which several sets of fragment ions are produced. It was also a key point to distinguish the dissociation regimes induced by both particles. A comparison with previous experimental results is also presented.

  13. Dissociation and the Development of Psychopathology.

    Science.gov (United States)

    Putnam, Frank W.; Trickett, Penelope K.

    This paper reviews the research on dissociation and the development of psychopathology in children and adolescents. Definitions and dimensions of dissociation are addressed, noting its range from normative daydreaming to the extremes found in individuals with multiple personality disorder. Memory dysfunctions, disturbances of identity, passive…

  14. Inflight dissociation of zircon in air plasma

    Energy Technology Data Exchange (ETDEWEB)

    Yugeswaran, S; Selvarajan, V [Bharathiar University, Coimbatore 641046 (India); Ananthapadmanabhan, P V; Thiyagarajan, T K [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai - 400 085 (India); Nair, Janardhanan [Ion Arc Technologies Pvt Ltd, Coimbatore (India)

    2010-02-01

    Thermal dissociation of zircon can be conveniently carried out in a plasma reactor, which is characterized by high temperature, high energy density and high quench rate. Zirconia is recovered from this partially dissociated zircon by alkali leaching. Dissociation of zircon has been conventionally carried out in argon gas, which is expensive. The present paper reports experimental results on thermal dissociation of zircon in air plasma medium. Process simulation for 'inflight' dissociation of zircon in air plasma medium is also presented. The experimental system consists of a central hollow graphite electrode, which acts as the cathode and a graphite anode. The material to be processed is fed centrally through the cathode. The unique feature of the system is that it uses air as the working gas to generate the thermal plasma. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation was carried out over 10-25 kW power range. Results of the study indicate that complete dissociation of zircon to ZrO{sub 2} and silica could be accomplished at 25 kW in air plasma.

  15. Inflight dissociation of zircon in air plasma

    International Nuclear Information System (INIS)

    Yugeswaran, S; Selvarajan, V; Ananthapadmanabhan, P V; Thiyagarajan, T K; Nair, Janardhanan

    2010-01-01

    Thermal dissociation of zircon can be conveniently carried out in a plasma reactor, which is characterized by high temperature, high energy density and high quench rate. Zirconia is recovered from this partially dissociated zircon by alkali leaching. Dissociation of zircon has been conventionally carried out in argon gas, which is expensive. The present paper reports experimental results on thermal dissociation of zircon in air plasma medium. Process simulation for 'inflight' dissociation of zircon in air plasma medium is also presented. The experimental system consists of a central hollow graphite electrode, which acts as the cathode and a graphite anode. The material to be processed is fed centrally through the cathode. The unique feature of the system is that it uses air as the working gas to generate the thermal plasma. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation was carried out over 10-25 kW power range. Results of the study indicate that complete dissociation of zircon to ZrO 2 and silica could be accomplished at 25 kW in air plasma.

  16. Coulomb dissociation of N-20,N-21

    NARCIS (Netherlands)

    Roeder, Marko; Adachi, Tatsuya; Aksyutina, Yulia; Alcantara, Juan; Altstadt, Sebastian; Alvarez-Pol, Hector; Ashwood, Nicholas; Atar, Leyla; Aumann, Thomas; Avdeichikov, Vladimir; Barr, M.; Beceiro, Saul; Bemmerer, Daniel; Benlliure, Jose; Bertulani, Carlos; Boretzky, Konstanze; Borge, Maria J. G.; Burgunder, G.; Caamano, Manuel; Caesar, Christoph; Casarejos, Enrique; Catford, Wilton; Cederkall, Joakim; Chakraborty, S.; Chartier, Marielle; Chulkov, Leonid; Cortina-Gil, Dolores; Crespo, Raquel; Pramanik, Ushasi Datta; Diaz-Fernandez, Paloma; Dillmann, Iris; Elekes, Zoltan; Enders, Joachim; Ershova, Olga; Estrade, A.; Farinon, F.; Fraile, Luis M.; Freer, Martin; Freudenberger, M.; Fynbo, Hans; Galaviz, Daniel; Geissel, Hans; Gernhaeuser, Roman; Goebel, Kathrin; Kalantar-Nayestanaki, Nasser; Najafi, Mohammad Ali; Rigollet, Catherine; Stoica, V.; Streicher, Branislav; Van de Walle, J.

    2016-01-01

    Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N-20,N-21 are reported. Relativistic N-20,N-21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a

  17. Dissociative depression among women in the community.

    Science.gov (United States)

    Sar, Vedat; Akyüz, Gamze; Oztürk, Erdinç; Alioğlu, Firdevs

    2013-01-01

    This study screened the prevalence and correlates of dissociative disorders among depressive women in the general population. The Dissociative Disorders Interview Schedule and the posttraumatic stress disorder (PTSD) and borderline personality disorder sections of the Structured Clinical Interview for DSM-IV were administered to 628 women in 500 homes. The prevalence of current major depressive episode was 10.0%. Of the women, 26 (40.6%) had the lifetime diagnosis of a DSM-IV, dissociative disorder, yielding a prevalence of 4.1% for dissociative depression. This group was younger (mean age = 30.7 years) than the nondissociative depression women (mean age = 39.6 years). There was no difference between the 2 groups on comorbid somatization disorder, PTSD, or borderline personality disorder. Besides suicide attempts, the dissociative group was characterized by secondary features of dissociative identity disorder; Schneiderian symptoms; borderline personality disorder criteria; and extrasensory perceptions, including possession experiences. They reported suicidality, thoughts of guilt and worthlessness, diminished concentration and indecisiveness, and appetite and weight changes more frequently than the nondissociative group. Early cessation of school education and childhood sexual abuse were frequently reported by the dissociative depression group. With its distinct features, the concept of dissociative depression may facilitate understanding of treatment resistance in, development of better psychotherapy strategies for, and new thinking on the neurobiology and pharmacotherapy of depressive disorders.

  18. Dissociation of ethane by electron impact

    International Nuclear Information System (INIS)

    Winters, H.F.

    1979-01-01

    The absolute total dissociation cross section for ethane is reported for electron energies between 10 and 600 eV. A maximum value of 7.6 X 10 -16 cm 2 occurs at 80 eV while the apparent threshold is approximately 10 eV. Dissociative ionization is more probable than dissociation into neutral fragments at all energies except in the threshold region. The data indicates that fragmentation involving methane elimination (e - +C 2 H 6 → CH 4 + CH 2 ) occurs in less than 2% of the dissociative events for 50 < E < 600 eV. Arguments are presented which suggest that some of the lower excited states of ethane are stable against dissociation. (Auth.)

  19. Is the dissociative adult suggestible? A test of the trauma and fantasy models of dissociation.

    Science.gov (United States)

    Kluemper, Nicole S; Dalenberg, Constance

    2014-01-01

    Psychologists have long assumed a connection between traumatic experience and psychological dissociation. This hypothesis is referred to as the trauma model of dissociation. In the past decade, a series of papers have been published that question this traditional causal link, proposing an alternative fantasy model of dissociation. In the present research, the relationship among dissociation, suggestibility, and fantasy proneness was examined. Suggestibility was measured through the Gudjonsson Scale of Interrogative Suggestibility (GSS) as well as an autobiographically based version of this measure based on the events of September 11, 2001. Consistent with prior research and with the trauma model, dissociation correlated positively with trauma severity (r = .32, p suggestibility measure. Although some participants did become quite emotional during the procedure, the risk/benefit ratio was perceived by almost all participants to be positive, with more reactive individuals evaluating the procedure more positively. The results consistently support the trauma model of dissociation and fail to support the fantasy model of dissociation.

  20. Dissociation and Memory Fragmentation in Posttraumatic Stress Disorder: An Evaluation of the Dissociative Encoding Hypothesis

    Science.gov (United States)

    Bedard-Gilligan, Michele; Zoellner, Lori A.

    2012-01-01

    Several prominent theories of posttraumatic stress disorder (PTSD) posit that peritraumatic dissociation results in insufficient encoding of the trauma memory and that persistent dissociation prevents memory elaboration, resulting in memory fragmentation and PTSD. In this review, we summarize the empirical literature on peritraumatic and trait dissociation and trauma narrative fragmentation as measured by meta-memory and rater/objective coding. Across 16 studies to date, the association between dissociation and fragmentation was most prominent when examining peritraumatic dissociation and patient's own ratings of memory fragmentation. This relationship did not hold when examining trait dissociation or rater-coded or computer-generated measures of fragmentation. Thus, initial evidence points more toward a strong self-reported association between constructs that is not supported on more objective fragmentation coding. Measurement overlap, construct ambiguity, and exclusion of potential confounds may underlie lack of a strong association between dissociation and objective-rated fragmentation. PMID:22348400

  1. The Shutdown Dissociation Scale (Shut-D)

    Science.gov (United States)

    Schalinski, Inga; Schauer, Maggie; Elbert, Thomas

    2015-01-01

    The evolutionary model of the defense cascade by Schauer and Elbert (2010) provides a theoretical frame for a short interview to assess problems underlying and leading to the dissociative subtype of posttraumatic stress disorder. Based on known characteristics of the defense stages “fright,” “flag,” and “faint,” we designed a structured interview to assess the vulnerability for the respective types of dissociation. Most of the scales that assess dissociative phenomena are designed as self-report questionnaires. Their items are usually selected based on more heuristic considerations rather than a theoretical model and thus include anything from minor dissociative experiences to major pathological dissociation. The shutdown dissociation scale (Shut-D) was applied in several studies in patients with a history of multiple traumatic events and different disorders that have been shown previously to be prone to symptoms of dissociation. The goal of the present investigation was to obtain psychometric characteristics of the Shut-D (including factor structure, internal consistency, retest reliability, predictive, convergent and criterion-related concurrent validity). A total population of 225 patients and 68 healthy controls were accessed. Shut-D appears to have sufficient internal reliability, excellent retest reliability, high convergent validity, and satisfactory predictive validity, while the summed score of the scale reliably separates patients with exposure to trauma (in different diagnostic groups) from healthy controls. The Shut-D is a brief structured interview for assessing the vulnerability to dissociate as a consequence of exposure to traumatic stressors. The scale demonstrates high-quality psychometric properties and may be useful for researchers and clinicians in assessing shutdown dissociation as well as in predicting the risk of dissociative responding. PMID:25976478

  2. The Shutdown Dissociation Scale (Shut-D

    Directory of Open Access Journals (Sweden)

    Inga Schalinski

    2015-05-01

    Full Text Available The evolutionary model of the defense cascade by Schauer and Elbert (2010 provides a theoretical frame for a short interview to assess problems underlying and leading to the dissociative subtype of posttraumatic stress disorder. Based on known characteristics of the defense stages “fright,” “flag,” and “faint,” we designed a structured interview to assess the vulnerability for the respective types of dissociation. Most of the scales that assess dissociative phenomena are designed as self-report questionnaires. Their items are usually selected based on more heuristic considerations rather than a theoretical model and thus include anything from minor dissociative experiences to major pathological dissociation. The shutdown dissociation scale (Shut-D was applied in several studies in patients with a history of multiple traumatic events and different disorders that have been shown previously to be prone to symptoms of dissociation. The goal of the present investigation was to obtain psychometric characteristics of the Shut-D (including factor structure, internal consistency, retest reliability, predictive, convergent and criterion-related concurrent validity.A total population of 225 patients and 68 healthy controls were accessed. Shut-D appears to have sufficient internal reliability, excellent retest reliability, high convergent validity, and satisfactory predictive validity, while the summed score of the scale reliably separates patients with exposure to trauma (in different diagnostic groups from healthy controls.The Shut-D is a brief structured interview for assessing the vulnerability to dissociate as a consequence of exposure to traumatic stressors. The scale demonstrates high-quality psychometric properties and may be useful for researchers and clinicians in assessing shutdown dissociation as well as in predicting the risk of dissociative responding.

  3. The detection of iron protoporphyrin (heme b) in phytoplankton and marine particulate material by electrospray ionisation mass spectrometry – comparison with diode array detection

    Energy Technology Data Exchange (ETDEWEB)

    Gledhill, Martha, E-mail: m.gledhill@geomar.de

    2014-09-02

    Highlights: • Mass spectrometry was applied to the analysis of heme b in biological material. • Optimal conditions involved selective reactant monitoring of the heme b product ion. • The isotopic signature for this iron tetrapyrrole further improved selectivity. • Mass spectrometry and spectrophotometry were compared for heme b analysis. • Combining techniques made a powerful tool for analysis of heme in marine microbes. - Abstract: A mass spectrometric (MS) method for the identification of iron protoporphyrin (IX) (FePTP, heme b) in marine particulate material and phytoplankton is described. Electrospray ionisation of FePTP produced the molecular Fe(III)PTP{sup +} ion (m/z = 616) or the pseudomolecular [Fe(II)PTP + H]{sup +} ion (m/z = 617), depending on the oxidation state of the central iron ion. Collision induced dissociation (CID) in the ion trap mass spectrometer resulted in a single detected product ion (m/z = 557) indicative of loss of ethanoic acid from a carboxylic acid side chain. Widening the isolation width to 616 ± 3 resulted in production of a mass spectrum demonstrating the distinctive isotopic ratio of the iron containing fragment, further increasing the specificity of the analysis. Selective reactant monitoring (SRM) of the fragment ion (m/z = 557) was applied to the detection of FePTP after chromatography of ammoniacal OGP extracts of marine samples. The detection limit for FePTP analysed by SRM after chromatography was 1.2 ± 0.5 fmol. For phytoplankton samples, reasonably good agreement was achieved between results obtained with SRM and those obtained by monitoring absorbance at λ = 400 nm using a diode array detector (DAD). Use of SRM for analysis of particulate material obtained from the high latitude North Atlantic allowed for the analysis of FePTP in the presence of a co-eluting compound that interfered with detection by DAD. Simultaneous collection of mass spectra from m/z = 300 to 1500 resulted in identification of the

  4. Psychotherapy and Pharmacotherapy for Patients with Dissociative Identity Disorder

    OpenAIRE

    Gentile, Julie P.; Dillon, Kristy S.; Gillig, Paulette Marie

    2013-01-01

    There is a wide variety of what have been called “dissociative disorders,” including dissociative amnesia, dissociative fugue, depersonalization disorder, dissociative identity disorder, and forms of dissociative disorder not otherwise specified. Some of these diagnoses, particularly dissociative identity disorder, are controversial and have been questioned by many clinicians over the years. The disorders may be under-diagnosed or misdiagnosed, but many persons who have experienced trauma rep...

  5. Photodissociation of gaseous CH3COSH at 248 nm by time-resolved Fourier-transform infrared emission spectroscopy: Observation of three dissociation channels

    International Nuclear Information System (INIS)

    Hu, En-Lan; Tsai, Po-Yu; Fan, He; Lin, King-Chuen

    2013-01-01

    Upon one-photon excitation at 248 nm, gaseous CH 3 C(O)SH is dissociated following three pathways with the products of (1) OCS + CH 4 , (2) CH 3 SH + CO, and (3) CH 2 CO + H 2 S that are detected using time-resolved Fourier-transform infrared emission spectroscopy. The excited state 1 (n O , π * CO ) has a radiative lifetime of 249 ± 11 ns long enough to allow for Ar collisions that induce internal conversion and enhance the fragment yields. The rate constant of collision-induced internal conversion is estimated to be 1.1 × 10 −10 cm 3 molecule −1 s −1 . Among the primary dissociation products, a fraction of the CH 2 CO moiety may undergo further decomposition to CH 2 + CO, of which CH 2 is confirmed by reaction with O 2 producing CO 2 , CO, OH, and H 2 CO. Such a secondary decomposition was not observed previously in the Ar matrix-isolated experiments. The high-resolution spectra of CO are analyzed to determine the ro-vibrational energy deposition of 8.7 ± 0.7 kcal/mol, while the remaining primary products with smaller rotational constants are recognized but cannot be spectrally resolved. The CO fragment detected is mainly ascribed to the primary production. A prior distribution method is applied to predict the vibrational distribution of CO that is consistent with the experimental findings.

  6. Probing the lowest coordination number of dianionic platinum-cyanide complexes in the gas phase: Dynamics of the charge dissociation process

    DEFF Research Database (Denmark)

    Bojesen, G; Hvelplund, P; Jørgensen, Thomas J. D.

    2000-01-01

    Low-energy and high-energy collision induced dissociation techniques are used to study the dissociation behavior of the gaseous Pt(CN)(6)(2-) and Pt(CN)(4)(2-) dianion complexes in order to probe the smallest stable dianion complex. Loss of neutral molecules from Pt(CN)(6)(2-) occurs resulting...... in Pt(CN)(5)(2-) and Pt(CN)(4)(2-), but no indication of the existence of Pt(CN)(3)(2-) was found. This indicates that the lifetime of Pt(CN)(3)(2-) is less than 4 mus (the flight time from the collision region to the detector). In contrast, all monoanion platinum-cyanide complexes were observed, i.......e., Pt(CN)(n)(-) (n=1-6). The kinetic energy released in processes where monoanions are formed is much lower than the barrier height for the reverse reaction (>1.5 eV), which indicates that electron detachment is involved, e.g., Pt(CN)(3)(-) and CN- are not formed in the same dynamical process from Pt(CN...

  7. Development and Application of an MSALL-Based Approach for the Quantitative Analysis of Linear Polyethylene Glycols in Rat Plasma by Liquid Chromatography Triple-Quadrupole/Time-of-Flight Mass Spectrometry.

    Science.gov (United States)

    Zhou, Xiaotong; Meng, Xiangjun; Cheng, Longmei; Su, Chong; Sun, Yantong; Sun, Lingxia; Tang, Zhaohui; Fawcett, John Paul; Yang, Yan; Gu, Jingkai

    2017-05-16

    Polyethylene glycols (PEGs) are synthetic polymers composed of repeating ethylene oxide subunits. They display excellent biocompatibility and are widely used as pharmaceutical excipients. To fully understand the biological fate of PEGs requires accurate and sensitive analytical methods for their quantitation. Application of conventional liquid chromatography-tandem mass spectrometry (LC-MS/MS) is difficult because PEGs have polydisperse molecular weights (MWs) and tend to produce multicharged ions in-source resulting in innumerable precursor ions. As a result, multiple reaction monitoring (MRM) fails to scan all ion pairs so that information on the fate of unselected ions is missed. This Article addresses this problem by application of liquid chromatography-triple-quadrupole/time-of-flight mass spectrometry (LC-Q-TOF MS) based on the MS ALL technique. This technique performs information-independent acquisition by allowing all PEG precursor ions to enter the collision cell (Q2). In-quadrupole collision-induced dissociation (CID) in Q2 then effectively generates several fragments from all PEGs due to the high collision energy (CE). A particular PEG product ion (m/z 133.08592) was found to be common to all linear PEGs and allowed their total quantitation in rat plasma with high sensitivity, excellent linearity and reproducibility. Assay validation showed the method was linear for all linear PEGs over the concentration range 0.05-5.0 μg/mL. The assay was successfully applied to the pharmacokinetic study in rat involving intravenous administration of linear PEG 600, PEG 4000, and PEG 20000. It is anticipated the method will have wide ranging applications and stimulate the development of assays for other pharmaceutical polymers in the future.

  8. Characterization of Steroidal Saponins from Dioscorea villosa and D. cayenensis Using Ultrahigh Performance Liquid Chromatography/Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry

    Science.gov (United States)

    Avula, Bharathi; Wang, Yan-Hong; Wang, Mei; Ali, Zulfiqar; Smillie, Troy J.; Zweigenbaum, Jerry; Khan, Ikhlas A.

    2017-01-01

    Yam (Dioscorea spp.) is an important edible tuber plant used for medicinal purposes to promote health and longevity in Chinese tradition. Steroidal saponins were reported to be the major physiologically active constituents in yams. In this current work, the structural characteristics of steroidal saponins in methanolic extracts from dried rhizomes of two Dioscorea species (D. villosa L. and D. cayenensis Lam.) and dietary supplements have been identified and analyzed using UHPLC/QTOF-MS in both negative and positive ion modes. The fragmentation patterns of reference standards were determined and the steroidal saponins in the extracts were identified or tentatively characterized from their retention times and mass spectra. The fragments produced by collision-induced dissociation (CID) revealed the characteristic cleavage of glycosidic bonds, and the fragmentation pattern provided structural information about the sugars. Twenty-one saponins, including four tentatively identified compounds, were detected in the crude extracts of two Dioscorea species. These saponins can be used to distinguish D. villosa from D. cayenensis. For example, asperin and gracillin are found only in D. cayenensis, and dioscoreavilloside A and B and parvifloside are only found in D. villosa. This can be used to determine the presence or absence of D. villosa in commercial products, which may help determine the spiking of plant material, and/or prevent the use of potentially mislabeled or misidentified “Dioscorea” material. The analytical method also provided an alternative, fast method for quality control of Dioscorea species in dietary supplements. Principal component analysis showed that Dioscorea species and commercial products were easily distinguished. From this a partial least squares model was constructed to determine what species are in different products. PMID:24510365

  9. Ions generated from uranyl nitrate solutions by electrospray ionization (ESI) and detected with Fourier transform ion-cyclotron resonance (FT-ICR) mass spectrometry.

    Science.gov (United States)

    Pasilis, Sofie; Somogyi, Arpád; Herrmann, Kristin; Pemberton, Jeanne E

    2006-02-01

    Electrospray ionization (ESI) of uranyl nitrate solutions generates a wide variety of positively and negatively charged ions, including complex adducts of uranyl ions with methoxy, hydroxy, and nitrate ligands. In the positive ion mode, ions detected by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry are sensitive to instrumental tuning parameters such as quadrupole operating frequency and trapping time. Positive ions correspond to oligomeric uranyl nitrate species that can be characterized as having a general formula of [(UO(2))(n)(A)(m)(CH(3)OH)(s)](+) or [(UO(2))(n)(O)(A)(m)(CH(3)OH)(s)](+) with n = 1-4, m = 1-7, s = 0 or 1, and A = OH, NO(3), CH(3)O or a combination of these, although the formation of NO(3)-containing species is preferred. In the negative ion mode, complexes of the form [(UO(2))(NO(3))(m)](-) (m = 1-3) are detected, although the formation of the oxo-containing ions [(UO(2))(O)(n)(NO(3))(m)](-) (n = 1-2, m = 1-2) and the hydroxy-containing ions [(UO(2))(OH)(n)(NO(3))(m)](-) (n = 1-2, m = 0-1) are also observed. The extent of coordinative unsaturation of both positive and negative ions can be determined by ligand association/exchange and H/D exchange experiments using D(2)O and CD(3)OD as neutral reaction partners in the gas-phase. Positive ions are of varying stability and reactivity and may fragment extensively upon collision with D(2)O, CD(3)OD and N(2) in sustained off-resonance irradiation/collision-induced dissociation (SORI-CID) experiments. Electron-transfer reactions, presumably occurring during electrospray ionization but also in SORI-CID, can result in reduction of U(VI) to U(V) and perhaps even U(IV).

  10. Profiling of oxidized phospholipids in lipoproteins from patients with coronary artery disease by hollow fiber flow field-flow fractionation and nanoflow liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lee, Ju Yong; Byeon, Seul Kee; Moon, Myeong Hee

    2015-01-20

    Oxidized phospholipids (Ox-PLs) are oxidatively modified PLs that are produced during the oxidation of lipoproteins; oxidation of low density lipoproteins especially is known to be associated with the development of coronary artery disease (CAD). In this study, different lipoprotein classes (high density, low density, and very low density lipoproteins) from pooled plasma of CAD patients and pooled plasma from healthy controls were size-sorted on a semipreparative scale by multiplexed hollow fiber flow field-flow fractionation (MxHF5), and Ox-PLs that were extracted from each lipoprotein fraction were quantified by nanoflow liquid chromatography-tandem mass spectrometry (nLC-ESI-MS/MS). The present study showed that oxidation of lipoproteins occurred throughout all classes of lipoproteins with more Ox-PLs identified from CAD patient lipoproteins: molecular structures of 283 unique PL species (including 123 Ox-PLs) from controls and 315 (including 169 Ox-PLs) from patients were identified by data-dependent collision-induced dissociation experiments. It was shown that oxidation of PLs occurred primarily with hydroxylation of PL; in particular, a saturated acyl chain such as 16:0, 18:0, or even 18:1 at the sn-1 location of the glycerol backbone along with sn-2 acyl chains with at least two double bonds were identified. The acyl chain combinations commonly found for hydroxylated Ox-PLs in the lipoproteins of CAD patients were 16:0/18:2, 16:0/20:4, 18:0/18:2, and 18:0/20:4.

  11. Dissociative Part-Dependent Resting-State Activity in Dissociative Identity Disorder : A Controlled fMRI Perfusion Study

    NARCIS (Netherlands)

    Schlumpf, Yolanda R.; Reinders, Antje A. T. S.; Nijenhuis, Ellert R. S.; Luechinger, Roger; van Osch, Matthias J. P.; Jaencke, Lutz

    2014-01-01

    Background: In accordance with the Theory of Structural Dissociation of the Personality (TSDP), studies of dissociative identity disorder (DID) have documented that two prototypical dissociative subsystems of the personality, the "Emotional Part'' (EP) and the "Apparently Normal Part'' (ANP), have

  12. An efficient algorithmic approach for mass spectrometry-based disulfide connectivity determination using multi-ion analysis

    Directory of Open Access Journals (Sweden)

    Yen Ten-Yang

    2011-02-01

    Full Text Available Abstract Background Determining the disulfide (S-S bond pattern in a protein is often crucial for understanding its structure and function. In recent research, mass spectrometry (MS based analysis has been applied to this problem following protein digestion under both partial reduction and non-reduction conditions. However, this paradigm still awaits solutions to certain algorithmic problems fundamental amongst which is the efficient matching of an exponentially growing set of putative S-S bonded structural alternatives to the large amounts of experimental spectrometric data. Current methods circumvent this challenge primarily through simplifications, such as by assuming only the occurrence of certain ion-types (b-ions and y-ions that predominate in the more popular dissociation methods, such as collision-induced dissociation (CID. Unfortunately, this can adversely impact the quality of results. Method We present an algorithmic approach to this problem that can, with high computational efficiency, analyze multiple ions types (a, b, bo, b*, c, x, y, yo, y*, and z and deal with complex bonding topologies, such as inter/intra bonding involving more than two peptides. The proposed approach combines an approximation algorithm-based search formulation with data driven parameter estimation. This formulation considers only those regions of the search space where the correct solution resides with a high likelihood. Putative disulfide bonds thus obtained are finally combined in a globally consistent pattern to yield the overall disulfide bonding topology of the molecule. Additionally, each bond is associated with a confidence score, which aids in interpretation and assimilation of the results. Results The method was tested on nine different eukaryotic Glycosyltransferases possessing disulfide bonding topologies of varying complexity. Its performance was found to be characterized by high efficiency (in terms of time and the fraction of search space

  13. Electron detachment dissociation of fluorescently labeled sialylated oligosaccharides.

    Science.gov (United States)

    Zhou, Wen; Håkansson, Kristina

    2011-12-01

    We explored the application of electron detachment dissociation (EDD) and infrared multiphoton dissociation (IRMPD) tandem mass spectrometry to fluorescently labeled sialylated oligosaccharides. Standard sialylated oligosaccharides and a sialylated N-linked glycan released from human transferrin were investigated. EDD yielded extensive glycosidic cleavages and cross-ring cleavages in all cases studied, consistently providing complementary structural information compared with infrared multiphoton dissociation. Neutral losses and satellite ions such as C-2H ions were also observed following EDD. In addition, we examined the influence of different fluorescent labels. The acidic label 2-aminobenzoic acid (2-AA) enhanced signal abundance in negative-ion mode. However, few cross-ring fragments were observed for 2-AA-labeled oligosaccharides. The neutral label 2-aminobenzamide (2-AB) resulted in more cross-ring cleavages compared with 2-AA-labeled species, but not as extensive fragmentation as for native oligosaccharides, likely resulting from altered negative charge locations from introduction of the fluorescent tag. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. From state dissociation to status dissociatus.

    Science.gov (United States)

    Antelmi, Elena; Ferri, Raffaele; Iranzo, Alex; Arnulf, Isabelle; Dauvilliers, Yves; Bhatia, Kailash P; Liguori, Rocco; Schenck, Carlos H; Plazzi, Giuseppe

    2016-08-01

    The states of being are conventionally defined by the simultaneous occurrence of behavioral, neurophysiological and autonomic descriptors. State dissociation disorders are due to the intrusion of features typical of a different state into an ongoing state. Disorders related to these conditions are classified according to the ongoing main state and comprise: 1) Dissociation from prevailing wakefulness as seen in hypnagogic or hypnopompic hallucinations, automatic behaviors, sleep drunkenness, cataplexy and sleep paralysis 2) Dissociation from rapid eye movement (REM) sleep as seen in REM sleep behavior disorder and lucid dreaming and 3) Dissociation from NREM sleep as seen in the disorders of arousal. The extreme expression of states dissociation is characterized by the asynchronous occurrence of the various components of the different states that prevents the recognition of any state of being. This condition has been named status dissociatus. According to the underlying disorders/diseases and to their severity, among status dissociatus we may recognize disorders in which such an extreme dissociation occurs only at night time or intermittently (i.e., autoimmune encephalopathies, narcolepsy type 1 and IgLON5 parasomnia), and others in which it occurs nearly continuously with complete loss of any conventionally defined state of being, and of the circadian pattern (agrypnia excitata). Here, we render a comprehensive review of all diseases/disorders associated with state dissociation and status dissociatus and propose a critical classification of this complex scenario. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Dissociation in Psychiatric Disorders: A Meta-Analysis of Studies Using the Dissociative Experiences Scale.

    Science.gov (United States)

    Lyssenko, Lisa; Schmahl, Christian; Bockhacker, Laura; Vonderlin, Ruben; Bohus, Martin; Kleindienst, Nikolaus

    2018-01-01

    Dissociation is a complex, ubiquitous construct in psychopathology. Symptoms of dissociation are present in a variety of mental disorders and have been connected to higher burden of illness and poorer treatment response, and not only in disorders with high levels of dissociation. This meta-analysis offers a systematic and evidence-based study of the prevalence and distribution of dissociation, as assessed by the Dissociative Experiences Scale, within different categories of mental disorders, and it updates an earlier meta-analysis. More than 1,900 original publications were screened, and 216 were included in the meta-analysis, comprising 15,219 individuals in 19 diagnostic categories. The largest mean dissociation scores were found in dissociative disorders (mean scores >35), followed by posttraumatic stress disorder, borderline personality disorder, and conversion disorder (mean scores >25). Somatic symptom disorder, substance-related and addictive disorders, feeding and eating disorders, schizophrenia, anxiety disorder, OCD, and most affective disorders also showed mean dissociation scores >15. Bipolar disorders yielded the lowest dissociation scores (mean score, 14.8). The findings underline the importance of careful psychopathological assessment of dissociative symptoms in the entire range of mental disorders.

  16. Dissociative identity disorder: a controversial diagnosis.

    Science.gov (United States)

    Gillig, Paulette Marie

    2009-03-01

    A brief description of the controversies surrounding the diagnosis of dissociative identity disorder is presented, followed by a discussion of the proposed similarities and differences between dissociative identity disorder and borderline personality disorder. The phenomenon of autohypnosis in the context of early childhood sexual trauma and disordered attachment is discussed, as is the meaning of alters or alternate personalities. The author describes recent neurosciences research that may relate the symptoms of dissociative identity disorder to demonstrable disordered attention and memory processes. A clinical description of a typical patient presentation is included, plus some recommendations for approaches to treatment.

  17. Dissociative recombination of molecular ions H2+

    International Nuclear Information System (INIS)

    Abarenov, A.V.; Marchenko, V.S.

    1989-01-01

    The total cross sections of dissociation and dissociative recombination of slow electrons and molecular ions H 2 + have been calculated in terms of the quasiclassical and dipole approximations. In the calculations allowance was made for the quantum nature of vibrational motion of heavy particles and presence of autoionization of divergence states of the H 2 (Σ u , nl) molecules. It is shown that the H 2 + ion dissociation cross sections are dominant in increase of the electron energy in the ε >or approx. 2-3 eV region for H 2 + (v) ion distribution over the vibrational levels characteristic for the beam experiments. 15 refs.; 5 figs

  18. Collision-induced basalt eruptions at Pleiku and Buôn Mê Thuột, south-central Viet Nam

    Science.gov (United States)

    Hoàng, Nguyễn; Flower, Martin F. J.; Chí, Cung Thu'ọ'ng; Xuân, Phạm Tích; Quý, Hoàng Văn; Sơn, Trần Thanh

    2013-09-01

    Neogene-Quaternary basalts occur as dispersed volcanic clusters in the vicinity of the Tethyan tectonic belt, possibly representing 'far-field' effects of the Early Tertiary collisions of Gondwana fragments with the southern margin of Eurasia. In Indochina, such a 'Diffuse Igneous Province' post-dates the 45-42 Ma 'hard' India-Asia collision and southeastward, collision induced (c. 30-17 Ma.), extrusion of Indochina. Extrusion was accommodated by left-lateral strike-slip shearing on the Ailao Shan-Red River Fault, coeval with seafloor spreading in the East Viet Nam (South China) Sea. The Indochina basalts mostly comprise shield-building tholeiites capped by small-volume undersaturated types, the latter often bearing mantle xenoliths and 'exotic' xenocrysts such as sapphire, zircon. They appeared at c. 17 Ma, more-or-less coinciding with the cessation of both continental extrusion and seafloor spreading. At this point extensional stress appears to have shifted westwards to continental Indochina, with magmatic activity appearing, characteristically, at 'pull-apart' basins. However, the relationship of mantle melting beneath this region to its geodynamic setting is controversial, being variously attributed to mantle plumes, extreme lithospheric stretching, and lateral asthenospheric displacement. There is little or no definitive evidence for regional mantle upwelling while lithosphere stretching alone appears to be insufficient to allow for melting, Here, we present geochemical and Sr, Nd, and Pb isotopic (and paleomagnetic data), for cored sections from the Pleiku and Buon Mê Thuột plateaus in south-central Viet Nam, representative in most respects of the Indochina province as a whole. In the Pleiku shield olivine tholeiite flows are intercalated with quartz tholeiites while, in contrast, alkali basalts predominate over olivine tholeiite in the Buon Mê Thuột (BMT) shield. The first of these features (in Pleiku) probably reflects crustal wall-rock reaction while

  19. Double diffractive dissociation in the reaction K-p→K-π+π-nπ+ at 14.3 GeV/c and pomeron factorisation

    International Nuclear Information System (INIS)

    Denegri, D.; Pons, Y.; Borg, A.; Spiro, M.; Paler, K.; Tovey, S.; Comber, C.; Shah, T.P.

    1975-01-01

    Evidence is presented for the double dissociation process K - p→QN*sub(1/2)→(anti K* 0 π - ) (nπ + ) at 14.3GeV/c. The cross section for the process is of the order of 10 μb. The production differential cross section is steep (for near-threshold excitation masses), as typical of diffractive processes, and exhibits a strong correlation between the production slope and the masses of the dissociated systems. The spin-parity composition and states of the two dissociation systems closely resemble those found in single dissociation, indicating that a common diffraction-like mechanism is responsible for both processes. The mass variations of the differential cross-section slope, the decay angular correlations and the total cross section of the double dissociation component are consistent with the predictions of a factorisable pomeron exchange model. (Auth.)

  20. Electron-impact dissociative ionization of CClF3 and CCl3F

    International Nuclear Information System (INIS)

    Martinez, Roberto; Sierra, Borja; Basterretxea, Francisco J.; Sanchez Rayo, Maria N.; Castano, Fernando

    2006-01-01

    A crossed-beam experiment of well characterized kinetic energy (KE) electrons and supersonic halomethanes CCl 3 F and CClF 3 in Ar carrier has been carried out in order to quantify the kinetic energy distributions (KEDs), the appearance energies (AEs) and the channels involved in the production of nascent ions. The ion KEDs were derived from the band profiles of the time-of-flight mass spectrum and the total KEDs computed using conservation laws. Heavier ions are created with KED peaked at thermal energies in contrast with low mass atoms or other fragments, where the distribution is broader and the maximum is at much higher energies. A discussion of the dissociative ionization pathways derived from the appearance energies, total average KEDs, thermodynamic enthalpies and computed electron dissociation energies is reported. The role of the vibrational and rotational energies into the dissociative processes is also discussed

  1. Kinetics of the urea-induced dissociation of human plasma alpha-2-macroglobulin as measured by small-angle neutron scattering

    DEFF Research Database (Denmark)

    Sjöberg, B.; Pap, S.; Järnberg, S.-E.

    1991-01-01

    The kinetics of the urea-induced dissociation of human plasma alpha-2-macroglobulin into two half-molecular fragments was investigated at 21.0-degrees-C by using small-angle neutron scattering. The relative change in molecular mass that occurs upon dissociation was monitored by recording the forw...

  2. Hypnotic suggestibility, cognitive inhibition, and dissociation.

    Science.gov (United States)

    Dienes, Zoltán; Brown, Elizabeth; Hutton, Sam; Kirsch, Irving; Mazzoni, Giuliana; Wright, Daniel B

    2009-12-01

    We examined two potential correlates of hypnotic suggestibility: dissociation and cognitive inhibition. Dissociation is the foundation of two of the major theories of hypnosis and other theories commonly postulate that hypnotic responding is a result of attentional abilities (including inhibition). Participants were administered the Waterloo-Stanford Group Scale of Hypnotic Susceptibility, Form C. Under the guise of an unrelated study, 180 of these participants also completed: a version of the Dissociative Experiences Scale that is normally distributed in non-clinical populations; a latent inhibition task, a spatial negative priming task, and a memory task designed to measure negative priming. The data ruled out even moderate correlations between hypnotic suggestibility and all the measures of dissociation and cognitive inhibition overall, though they also indicated gender differences. The results are a challenge for existing theories of hypnosis.

  3. The co-occurrence of PTSD and dissociation: differentiating severe PTSD from dissociative-PTSD.

    Science.gov (United States)

    Armour, Cherie; Karstoft, Karen-Inge; Richardson, J Don

    2014-08-01

    A dissociative-posttraumatic stress disorder (PTSD) subtype has been included in the DSM-5. However, it is not yet clear whether certain socio-demographic characteristics or psychological/clinical constructs such as comorbid psychopathology differentiate between severe PTSD and dissociative-PTSD. The current study investigated the existence of a dissociative-PTSD subtype and explored whether a number of trauma and clinical covariates could differentiate between severe PTSD alone and dissociative-PTSD. The current study utilized a sample of 432 treatment seeking Canadian military veterans. Participants were assessed with the Clinician Administered PTSD Scale (CAPS) and self-report measures of traumatic life events, depression, and anxiety. CAPS severity scores were created reflecting the sum of the frequency and intensity items from each of the 17 PTSD and 3 dissociation items. The CAPS severity scores were used as indicators in a latent profile analysis (LPA) to investigate the existence of a dissociative-PTSD subtype. Subsequently, several covariates were added to the model to explore differences between severe PTSD alone and dissociative-PTSD. The LPA identified five classes: one of which constituted a severe PTSD group (30.5 %), and one of which constituted a dissociative-PTSD group (13.7 %). None of the included, demographic, trauma, or clinical covariates were significantly predictive of membership in the dissociative-PTSD group compared to the severe PTSD group. In conclusion, a significant proportion of individuals report high levels of dissociation alongside their PTSD, which constitutes a dissociative-PTSD subtype. Further investigation is needed to identify which factors may increase or decrease the likelihood of membership in a dissociative-PTSD subtype group compared to a severe PTSD only group.

  4. Dissociation of NF3 in shock waves

    International Nuclear Information System (INIS)

    Breshears, W.D.; Bird, P.F.

    1978-01-01

    The thermal dissociation rate of NF 3 in mixtures of 5% and 10%NF 3 in Ar has been measured behind incident shock waves over the temperature range 1330-2000 K. Dissociation rates were determined from postshock density gradients measured by laser beam deflection. The second order rate coefficient determined for NF 3 -Ar collisions is k/sub d/=2.31 x 10 15 exp(-20500/T) cm 3 mole sec

  5. Dissociation and decay of ultracold sodium molecules

    International Nuclear Information System (INIS)

    Mukaiyama, T.; Abo-Shaeer, J.R.; Xu, K.; Chin, J.K.; Ketterle, W.

    2004-01-01

    The dissociation of ultracold molecules was studied by ramping an external magnetic field through a Feshbach resonance. The observed dissociation energies directly yielded the strength of the atom-molecule coupling. They showed nonlinear dependence on the ramp speed. This was explained by a Wigner threshold law which predicts that the decay rate of the molecules above threshold increases with the density of states. In addition, inelastic molecule-molecule and molecule-atom collisions were characterized

  6. Schizophrenia masquerading as Dissociative Identity Disorder

    OpenAIRE

    Jegan Yogaratnam; Rajesh Jacob

    2012-01-01

    Dissociative symptoms can dominate the clinical picture in many psychiatric conditions and possess a huge challenge to the clinicians in management. We present a case report of a female with a strong family history of schizophrenia who initially presented with features suggestive of dissociative identity disorder, which is itself a rare clinical entity, was later diagnosed to have schizophrenia. Authors would like to emphasise that clinicians should have a high index of suspicion for schizoph...

  7. [Screening for major dissociative disorders with the FDS, the German version of the Dissociative Experience Scale].

    Science.gov (United States)

    Rodewald, Frauke; Gast, Ursula; Emrich, Hinderk M

    2006-06-01

    The prevalence of major dissociative disorders (dissociative identity disorder, DID and similar forms of dissociative disorder not otherwise specified, DDNOS) in clinical samples is about 5 %. Despite their frequency, major dissociative disorders are often overseen for a long time. Screening-scales have proved to be effective to support clinical diagnosis. The aim of this study was to test, whether the Fragebogen für dissoziative Symptome (FDS), the German version of the Dissociative Experiences Scale (DES), differentiates between patients with dissociative disorders, non-dissociative disorders and non-clinical controls. Additionally, an optimal FDS-cutoff for a more detailed differential-diagnostic evaluation of the dissociative symptomatology should be identified. 150 participants with DID (group DID: n = 44), DDNOS (DDNOS: n = 22), posttraumatic disorders (TRAUMA: n = 20), other non-dissociative disorders (non-TRAUMA: n = 34) and non-clinical controls (KG: n = 30) completed the FDS. In the five diagnostic groups, mean values were calculated and compared for the FDS, DES and FDS-20. Via receiver-operating-curves the cutoff-scores, which differentiated best between participants with and without major dissociative disorders, were identified. FDS, DES and FDS-20 differentiate significantly between patients with and without major dissociative disorders. For all scales, there were significant differences between the diagnostic groups, with mean-scores decreasing continuously from the groups DID to DDNOS and TRAUMA. Between the groups non-TRAUMA and KG tendencies were found in the predicted direction. The optimal cutoff-scores to differentiate between participants with and without major dissociative disorders were 13 (FDS/FDS-20) and 15 (DES). Using these cutoff-scores, at least 90 % of the patients with major dissociative disorders could be identified correctly (sensitivity). The specifity of the scales was 0.89 to 0.90. Screening for major dissociative disorders

  8. Dissociative Spectrum Disorders in the Primary Care Setting

    OpenAIRE

    Elmore, James L.

    2000-01-01

    Dissociative disorders have a lifetime prevalence of about 10%. Dissociative symptoms may occur in acute stress disorder, posttraumatic stress disorder, somatization disorder, substance abuse, trance and possession trance, Ganser's syndrome, and dissociative identity disorder, as well as in mood disorders, psychoses, and personality disorders. Dissociative symptoms and disorders are observed frequently among patients attending our rural South Carolina community mental health center. Given the...

  9. Fast kinetics of calcium dissociation from calsequestrin

    Directory of Open Access Journals (Sweden)

    MARIANELA BELTRÁN

    2006-01-01

    Full Text Available We measured the kinetics of calcium dissociation from calsequestrin in solution or forming part of isolated junctional sarcoplasmic reticulum membranes by mixing calsequestrin equilibrated with calcium with calcium-free solutions in a stopped-flow system. In parallel, we measured the kinetics of the intrinsic fluorescence changes that take place following calcium dissociation from calsequestrin. We found that at 25ºC calcium dissociation was 10-fold faster for calsequestrin attached to junctional membranes (k = 109 s-1 than in solution. These results imply that calcium dissociation from calsequestrin in vivo is not rate limiting during excitation-contraction coupling. In addition, we found that the intrinsic fluorescence decrease for calsequestrin in solution or forming part of junctional membranes was significantly slower than the rates of calcium dissociation. The kinetics of intrinsic fluorescence changes had two components for calsequestrin associated to junctional membranes and only one for calsequestrin in solution; the faster component was 8-fold faster (k = 54.1 s-1 than the slower component (k = 6.9 s-1, which had the same k value as for calsequestrin in solution. These combined results suggest that the presence of calsequestrin at high concentrations in a restricted space, such as when bound to the junctional membrane, accelerates calcium dissociation and the resulting structural changes, presumably as a result of cooperative molecular interactions.

  10. Isotope effects in photo dissociation of ozone with visible light

    Science.gov (United States)

    Früchtl, Marion; Janssen, Christof; Röckmann, Thomas

    2014-05-01

    Ozone (O3) plays a key role for many chemical oxidation processes in the Earth's atmosphere. In these chemical reactions, ozone can transfer oxygen to other trace gases. This is particularly interesting, since O3 has a very peculiar isotope composition. Following the mass dependent fractionation equation δ17O = 0.52 * δ18O, most fractionation processes depend directly on mass. However, O3 shows an offset to the mass dependent fractionation line. Processes, which show such anomalies, are termed mass independent fractionations (MIF). A very well studied example for a chemical reaction that leads to mass independent fractionation is the O3 formation reaction. To what degree O3 destruction reactions need to be considered in order to understand the isotope composition of atmospheric O3 is still not fully understood and an open question within scientific community. We set up new experiments to investigate the isotope effect resulting from photo dissociation of O3 in the Chappuis band (R1). Initial O3 is produced by an electric discharge. After photolysis O3 is collected in a cold trap at the triple point temperature of nitrogen (63K). O3 is then converted to O2 in order to measure the oxygen isotopes of O3 using isotope ratio mass spectrometry. To isolate O3 photo dissociation (R1) from O3 decomposition (R2) and secondary O3 formation (R3), we use varying amounts of carbon monoxide (CO) as O atom quencher (R4). In this way we suppress the O + O3 reaction (R3) and determine the isotope fractionation in R1 and R2 separately. We present first results on the isotope effects in O3 photo dissociation with visible light in the presence of different bath gases. Results are interpreted based on chemical kinetics modeling. (R1) O3 + hυ → O (3P) + O2 (R2) O3 + O (3P) → 2 O2 (R3) O + O2 + M → O3 + M (R4) O (3P) + CO + M → CO2 + M

  11. Electromagnetic dissociation of relativistic [sup 28]Si by nucleon emission

    Energy Technology Data Exchange (ETDEWEB)

    Sonnadara, U.J.

    1992-12-01

    A detailed study of the electromagnetic dissociation of [sup 28]Si by nucleon emission at E[sub lab]/A = 14.6 (GeV/nucleon was carried out with [sup 28]Si beams interacting on [sup 208]Pb). [sup 120]Sn. [sup 64]C targets. The measurements apparatus consists of detectors in the target area which measure the energy and charged multiplicity, and a forward spectrometer which measures the position, momentum and energy of the reaction fragments. The exclusive electromagnetic dissociation cross sections for decay channels having multiple nucleons in the final state have been measured which enables the selection of events produced in pure electromagnetic interactions. The measured cross sections agree well with previous measurements obtained for the removal of a few nucleons as well as with measurements on total charge removal cross sections from other experiments. The dependence of the integrated cross sections on the target charge Z[sub T] and the target mass AT confirms that for higher Z targets the excitation is largely electromagnetic. Direct measurements of the excitation energy for the electromagnetic dissociation of [sup 28]Si [yields] p+[sup 27]Al and [sup 28]Si [yields] n+[sup 27]Si have been obtained through a calculation of the invariant mass in kinematically, reconstructed events. The excitation energy spectrum for all targets peak near the isovector giant dipole resonance in [sup 28]Si. These distributions are well reproduced by combining the photon spectrum calculated using the Weizsaecker-Williams approximation with the experimental data on the photonuclear [sup 28]Si([sub [gamma],p])[sup 27]Al and [sup 28]Si([sub [gamma],n])[sup 27]Si. The possibilities of observing double giant dipole resonance excitations in [sup 28]Si have been investigated with cross section measurements as well as with excitation energy reconstruction.

  12. Infrared multiple photon dissociation spectroscopy of sodium and potassium chlorate anions

    NARCIS (Netherlands)

    Dain, R. P.; Leavitt, C. M.; Oomens, J.; Steill, J. D.; Groenewold, G. S.; van Stipdonk, M. J.

    2010-01-01

    The structures of gas-phase, metal chlorate anions with the formula [M(ClO3)(2)](-), M = Na and K, were determined using tandem mass spectrometry and infrared multiple photon dissociation (IRMPD) spectroscopy. Structural assignments for both anions are based on comparisons of the experimental

  13. Dissociation Pathways of Benzylpyridinium "Thermometer" Ions Depend on the Activation Regime: An IRMPD Spectroscopy Study

    NARCIS (Netherlands)

    Morsa, D.; Gabelica, V.; Rosu, F.; Oomens, J.; De Pauw, E.

    2014-01-01

    The dissociation of benzylpyridinium "thermometer" ions is widely used to calibrate the internal energy of ions produced in mass spectrometry. The fragmentation mechanism is usually believed to yield a benzylium cation, although recent studies suggest the possibility of a rearrangement leading to

  14. Dissociations between developmental dyslexias and attention deficits

    Science.gov (United States)

    Lukov, Limor; Friedmann, Naama; Shalev, Lilach; Khentov-Kraus, Lilach; Shalev, Nir; Lorber, Rakefet; Guggenheim, Revital

    2014-01-01

    We examine whether attention deficits underlie developmental dyslexia, or certain types of dyslexia, by presenting double dissociations between the two. We took into account the existence of distinct types of dyslexia and of attention deficits, and focused on dyslexias that may be thought to have an attentional basis: letter position dyslexia (LPD), in which letters migrate within words, attentional dyslexia (AD), in which letters migrate between words, neglect dyslexia, in which letters on one side of the word are omitted or substituted, and surface dyslexia, in which words are read via the sublexical route. We tested 110 children and adults with developmental dyslexia and/or attention deficits, using extensive batteries of reading and attention. For each participant, the existence of dyslexia and the dyslexia type were tested using reading tests that included stimuli sensitive to the various dyslexia types. Attention deficit and its type was established through attention tasks assessing sustained, selective, orienting, and executive attention functioning. Using this procedure, we identified 55 participants who showed a double dissociation between reading and attention: 28 had dyslexia with normal attention and 27 had attention deficits with normal reading. Importantly, each dyslexia with suspected attentional basis dissociated from attention: we found 21 individuals with LPD, 13 AD, 2 neglect dyslexia, and 12 surface dyslexia without attention deficits. Other dyslexia types (vowel dyslexia, phonological dyslexia, visual dyslexia) also dissociated from attention deficits. Examination of 55 additional individuals with both a specific dyslexia and a certain attention deficit found no attention function that was consistently linked with any dyslexia type. Specifically, LPD and AD dissociated from selective attention, neglect dyslexia dissociated from orienting, and surface dyslexia dissociated from sustained and executive attention. These results indicate that

  15. An exploration of the influence of diagonal dissociation and moderate changes in speed on locomotor parameters in trotting horses

    Directory of Open Access Journals (Sweden)

    Sarah Jane Hobbs

    2016-06-01

    Full Text Available Background. Although the trot is described as a diagonal gait, contacts of the diagonal pairs of hooves are not usually perfectly synchronized. Although subtle, the timing dissociation between contacts of each diagonal pair could have consequences on gait dynamics and provide insight into the functional strategies employed. This study explores the mechanical effects of different diagonal dissociation patterns when speed was matched between individuals and how these effects link to moderate, natural changes in trotting speed. We anticipate that hind-first diagonal dissociation at contact increases with speed, diagonal dissociation at contact can reduce collision-based energy losses and predominant dissociation patterns will be evident within individuals. Methods. The study was performed in two parts: in the first 17 horses performed speed-matched trotting trials and in the second, five horses each performed 10 trotting trials that represented a range of individually preferred speeds. Standard motion capture provided kinematic data that were synchronized with ground reaction force (GRF data from a series of force plates. The data were analyzed further to determine temporal, speed, GRF, postural, mass distribution, moment, and collision dynamics parameters. Results. Fore-first, synchronous, and hind-first dissociations were found in horses trotting at (3.3 m/s ± 10%. In these speed-matched trials, mean centre of pressure (COP cranio-caudal location differed significantly between the three dissociation categories. The COP moved systematically and significantly (P = .001 from being more caudally located in hind-first dissociation (mean location = 0.41 ± 0.04 through synchronous (0.36 ± 0.02 to a more cranial location in fore-first dissociation (0.32 ± 0.02. Dissociation patterns were found to influence function, posture, and balance parameters. Over a moderate speed range, peak vertical forelimb GRF had a strong relationship with dissociation

  16. Identification of regioisomers of methylated kaempferol and quercetin by ultra high performance liquid chromatography quadrupole time-of-flight (UHPLC–QTOF) tandem mass spectrometry combined with diagnostic fragmentation pattern analysis

    International Nuclear Information System (INIS)

    Ma, Chengying; Lv, Haipeng; Zhang, Xinzhong; Chen, Zongmao; Shi, Jiang; Lu, Meiling; Lin, Zhi

    2013-01-01

    Highlights: •Found methane elimination is position-specific for methylated flavonols. •Found retro Diels–Alder fragments retained methoxy at original ring of flavonols. •Proposed a diagnostic pattern for discriminating regioisomers of flavonols. •Identified the specificity of three novel flavonol O-methyltransferases. •Identified six biologically active compounds and four new compounds. -- Abstract: The O-methylation of active flavonoids can enhance their antiallergic, anticancerous, and cardioprotective effects depending on the methylation position. Thus, it is biologically and pharmacologically important to differentiate methylated flavonoid regioisomers. In this study, we examined the regioisomers of methylated kaempferol and quercetin using ultra high performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry. The methyl groups on the flavonoids can generally be cleaved as methyl radicals in a position-independent manner. We found that methyl groups can be cleaved as methane. If there are protons adjacent the methoxy on the flavonol rings, intra-molecule proton transfer can occur via collision-induced dissociation, and one molecule of methane can then be eliminated. The remaining charged fragment ([M+H−CH 4 ] + ) reflects the adjacent structure and is specific to the methoxy position. Furthermore, the retro Diels–Alder (RDA) fragmentation of methylated flavonols can generate fragments with the methoxy at the original methylated ring. Combining the position-specific [M+H−CH 4 ] + fragment with the RDA fragments provides a diagnostic pattern for rapidly identifying methylated regioisomeric flavonols. Along with their retention behaviour, we have successfully identified ten regioisomers of methylated kaempferol and quercetin, which include six compounds previously reported in plants and shown to be biologically active. The developed approach is sensitive, rapid, reliable, and requires few standard compounds. It is highly

  17. Dissociation mechanisms and dynamics of doubly charged CD3CN observed by PEPIPICO spectroscopy

    International Nuclear Information System (INIS)

    Harada, C.; Tada, S.; Yamamoto, K.; Senba, Y.; Yoshida, H.; Hiraya, A.; Wada, S.; Tanaka, K.; Tabayashi, K.

    2006-01-01

    Dissociation of free acetonitrile-d 3 molecule, CD 3 CN induced by core level excitation was studied near the nitrogen K-edge by time-of-flight fragment mass spectroscopy. A variety of atomic and molecular fragment cations such as D + , CD n + , C 2 D n + , and CD n CN + were detected using the effusive CD 3 CN beam. Photoelectron-photoion-photoion coincidence technique was applied to analyse the dissociation mechanisms and dynamics of doubly charged CD 3 CN 2+ following the N(1s-π * ) excitation. The charge separation mechanisms of core-excited CD 3 CN were discussed in connection with Auger final state distributions

  18. The co-occurrence of PTSD and dissociation: differentiating severe PTSD from dissociative-PTSD

    DEFF Research Database (Denmark)

    Armour, C.; Karstoft, K. I.; Richardson, J. D.

    2014-01-01

    A dissociative-posttraumatic stress disorder (PTSD) subtype has been included in the DSM-5. However, it is not yet clear whether certain socio-demographic characteristics or psychological/clinical constructs such as comorbid psychopathology differentiate between severe PTSD and dissociative-PTSD....... The current study investigated the existence of a dissociative-PTSD subtype and explored whether a number of trauma and clinical covariates could differentiate between severe PTSD alone and dissociative-PTSD. The current study utilized a sample of 432 treatment seeking Canadian military veterans. Participants...... were assessed with the Clinician Administered PTSD Scale (CAPS) and self-report measures of traumatic life events, depression, and anxiety. CAPS severity scores were created reflecting the sum of the frequency and intensity items from each of the 17 PTSD and 3 dissociation items. The CAPS severity...

  19. Isotope separation by photoselective dissociative electron

    International Nuclear Information System (INIS)

    Stevens, C.G.

    1978-01-01

    A method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule is described. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, 235 UF 6 is separated from a UF 6 mixture by selective excitation followed by dissociative electron capture into 235 UF 5 - and F

  20. Psychotherapy and pharmacotherapy for patients with dissociative identity disorder.

    Science.gov (United States)

    Gentile, Julie P; Dillon, Kristy S; Gillig, Paulette Marie

    2013-02-01

    There is a wide variety of what have been called "dissociative disorders," including dissociative amnesia, dissociative fugue, depersonalization disorder, dissociative identity disorder, and forms of dissociative disorder not otherwise specified. Some of these diagnoses, particularly dissociative identity disorder, are controversial and have been questioned by many clinicians over the years. The disorders may be under-diagnosed or misdiagnosed, but many persons who have experienced trauma report "dissociative" symptoms. Prevalence of dissociative disorders is unknown, but current estimates are higher than previously thought. This paper reviews clinical, phenomenological, and epidemiological data regarding diagnosis in general, and illustrates possible treatment interventions for dissociative identity disorder, with a focus on psychotherapy interventions and a review of current psychopharmacology recommendations as part of a comprehensive multidisciplinary treatment plan.

  1. Reconsidering the autohypnotic model of the dissociative disorders.

    Science.gov (United States)

    Dell, Paul F

    2018-03-22

    The dissociative disorders field and the hypnosis field currently reject the autohypnotic model of the dissociative disorders, largely because many correlational studies have shown hypnotizability and dissociation to be minimally related (r = .12). Curiously, it is also widely accepted that dissociative patients are highly hypnotizable. If dissociative patients are highly hypnotizable because only highly hypnotizable individuals can develop a dissociative disorder - as the author proposes - then the methodology of correlational studies of hypnotizability and dissociation in random clinical and community samples would necessarily be constitutively unable to detect, and statistically unable to reflect, that fact. That is, the autohypnotic, dissociative distancing of that small subset of highly hypnotizable individuals who repeatedly encountered intolerable circumstances is statistically lost among the data of (1) the highly hypnotizable subjects who do not dissociate and (2) subjects (of all levels of hypnotizability) who manifest other kinds of dissociation. The author proposes that, when highly hypnotizable individuals repeatedly engage in autohypnotic distancing from intolerable circumstances, they develop an overlearned, highly-motivated, automatized pattern of dissociative self-protection (i.e., a dissociative disorder). The author urges that theorists of hypnosis and the dissociative disorders explicitly include in their theories (a) the trait of high hypnotizability, (b) the phenomena of autohypnosis, and (c) the manifestations of systematized, autohypnotic pathology. Said differently, the author is suggesting that autohypnosis and autohypnotic pathology are unacknowledged nodes in the nomothetic networks of both hypnosis and dissociation.

  2. Characterization of aromatic organosulfur model compounds relevant to fossil fuels by using atmospheric pressure chemical ionization with CS2 and high-resolution tandem mass spectrometry.

    Science.gov (United States)

    Tang, Weijuan; Sheng, Huaming; Jin, Chunfen; Riedeman, James S; Kenttämaa, Hilkka I

    2016-04-15

    The chemistry of desulfurization involved in processing crude oil is greatly dependent on the forms of sulfur in the oil. Sulfur exists in different chemical bonding environments in fossil fuels, including those in thiophenes and benzothiophenes, thiols, sulfides, and disulfides. In this study, the fragmentation behavior of the molecular ions of 17 aromatic organosulfur compounds with various functionalities was systematically investigated by using high-resolution tandem mass spectrometry. Multiple-stage tandem mass spectrometric experiments were carried out using a linear quadrupole ion trap (LQIT) equipped with an atmospheric pressure chemical ionization (APCI) source. (+)APCI/CS2 was used to generate stable dominant molecular ions for all the compounds studied except for three sulfides that also showed abundant fragment ions. The LQIT coupled with an orbitrap mass spectrometer was used for elemental composition analysis, which facilitated the identification of the neutral molecules lost during fragmentation. The characteristic fragment ions generated in MS(2) and MS(3) experiments provide clues for the chemical bonding environment of sulfur atoms in the examined compounds. Upon collision-induced dissociation (CID), the molecular ions can lose the sulfur atom in a variety of ways, including as S (32 Da), HS(•) (33 Da), H2 S (34 Da), CS (44 Da), (•) CHS (45 Da) and CH2 S (46 Da). These neutral fragments are not only indicative of the presence of sulfur, but also of the type of sulfur present in the compound. Generally, losses of HS(•) and H2 S were found to be associated with compounds containing saturated sulfur functionalities, while losses of S, CS and (•) CHS were more common for heteroaromatic sulfur compounds. High-resolution tandem mass spectrometry with APCI/CS2 ionization is a viable approach to determining the types of organosulfur compounds. It can potentially be applied to analysis of complex mixtures, which is beneficial to improving the

  3. Dissociation in virtual reality: depersonalization and derealization

    Science.gov (United States)

    Garvey, Gregory P.

    2010-01-01

    This paper looks at virtual worlds such as Second Life7 (SL) as possible incubators of dissociation disorders as classified by the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition3 (also known as the DSM-IV). Depersonalization is where "a person feels that he or she has changed in some way or is somehow unreal." Derealization when "the same beliefs are held about one's surroundings." Dissociative Identity Disorder (DID), previously known as multiple personality disorder fits users of Second Life who adopt "in-world" avatars and in effect, enact multiple distinct identities or personalities (known as alter egos or alters). Select questions from the Structured Clinical Interview for Depersonalization (SCI-DER)8 will be discussed as they might apply to the user's experience in Second Life. Finally I would like to consider the hypothesis that rather than a pathological disorder, dissociation is a normal response to the "artificial reality" of Second Life.

  4. Double dissociation in the reaction K-p→K-π+π-Nπ+ at 14.3GeV/c and pomeron factorisation

    International Nuclear Information System (INIS)

    Denegri, D.; Pons, Y.; Borg, A.; Spiro, M.; Paler, K.; Tovey, S.; Combes, C.; Shah, T.P.

    1975-01-01

    Evidence for the double dissociation process K - p→QN*1/2→(antikaon neutral* π - ) (nπ + ) at 14.3GeV/c is presented. The cross section for this process is of the order of 10μb. The production differential cross section is steep, as typical of diffractive processes, and exhibits a strong correlation between the production slope and the dissociation system mass. The mass variation of the differential cross section slope and the total cross section of the double dissociation component are consistent with the factorisable Pomeron exchange model predictions [fr

  5. Molecular dynamics study of CO2 hydrate dissociation: Fluctuation-dissipation and non-equilibrium analysis.

    Science.gov (United States)

    English, Niall J; Clarke, Elaine T

    2013-09-07

    Equilibrium and non-equilibrium molecular dynamics (MD) simulations have been performed to investigate thermal-driven break-up of planar CO2 hydrate interfaces in liquid water at 300-320 K. Different guest compositions, at 85%, 95%, and 100% of maximum theoretical occupation, led to statistically-significant differences in the observed initial dissociation rates. The melting temperatures of each interface were estimated, and dissociation rates were observed to be strongly dependent on temperature, with higher dissociation rates at larger over-temperatures vis-à-vis melting. A simple coupled mass and heat transfer model developed previously was applied to fit the observed dissociation profiles, and this helps to identify clearly two distinct régimes of break-up; a second well-defined region is essentially independent of composition and temperature, in which the remaining nanoscale, de facto two-dimensional system's lattice framework is intrinsically unstable. From equilibrium MD of the two-phase systems at their melting point, the relaxation times of the auto-correlation functions of fluctuations in number of enclathrated guest molecules were used as a basis for comparison of the variation in the underlying, non-equilibrium, thermal-driven dissociation rates via Onsager's hypothesis, and statistically significant differences were found, confirming the value of a fluctuation-dissipation approach in this case.

  6. Dissociative amnesia: a case with management challenges

    Directory of Open Access Journals (Sweden)

    Priti Singh

    2015-07-01

    Full Text Available A case of dissociative amnesia with regressed behaviour was diagnosed applying the existing criteria for dissociative disorder in the tenth revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10. Though there are number of cases of such condition, but when coupled with regressed behaviour it adds to new dimension in the management. An applied strategy in lines with both pharmacological and non pharmacological was used, and we found that it helped our patient to gradually improve her behaviour. This is one of the few cases reported and we hope more such cases should be reported in understanding the psychopathology.

  7. Coulomb dissociation of N 20,21

    OpenAIRE

    Röder, Marko; Adachi, Tatsuya; Aksyutina, Yulia; Alcantara, Juan; Altstadt, Sebastian; Alvarez-Pol, Hector; Ashwood, Nicholas; Atar, Leyla; Aumann, Thomas; Avdeichikov, Vladimir; Barr, M.; Beceiro, Saul; Bemmerer, Daniel; Benlliure, Jose; Bertulani, Carlos

    2016-01-01

    Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N20,21 are reported. Relativistic N20,21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the N19(n,γ)N20 and N20(n,γ)N21 excitation functions and thermonuclear reaction rates have been determined. The N19(n,γ)N20 rate is...

  8. Objective documentation of child abuse and dissociation in 12 murderers with dissociative identity disorder.

    Science.gov (United States)

    Lewis, D O; Yeager, C A; Swica, Y; Pincus, J H; Lewis, M

    1997-12-01

    The skepticism regarding the existence of dissociative identity disorder as well as the abuse that engenders it persists for lack of objective documentation. This is doubly so for the disorder in murderers because of issues of suspected malingering. This article presents objective verification of both dissociative symptoms and severe abuse during childhood in a series of adult murderers with dissociative identity disorder. This study consisted of a review of the clinical records of 11 men and one woman with DSM-IV-defined dissociative identity disorder who had committed murder. Data were gathered from medical, psychiatric, social service, school, military, and prison records and from records of interviews with subjects' family members and others. Handwriting samples were also examined. Data were analyzed qualitatively. Signs and symptoms of dissociative identity disorder in childhood and adulthood were corroborated independently and from several sources in all 12 cases; objective evidence of severe abuse was obtained in 11 cases. The subjects had amnesia for most of the abuse and underreported it. Marked changes in writing style and/or signatures were documented in 10 cases. This study establishes, once and for all, the linkage between early severe abuse and dissociative identity disorder. Further, the data demonstrate that the disorder can be distinguished from malingering and from other disorders. The study shows that it is possible, with great effort, to obtain objective evidence of both the symptoms of dissociative identity disorder and the abuse that engenders it.

  9. Dissociative electron attachment on surfaces and in bulk media

    International Nuclear Information System (INIS)

    Fabrikant, Ilya I.

    2007-01-01

    A theory of dissociative electron attachment to molecules condensed at surfaces and embedded within bulk media is developed. The theory of low-energy electron diffraction is used to obtain the width for electron-molecule resonance scattering in the condensed phase from the width for the gas phase. It is then employed for the calculation of dissociative attachment in the framework of the nonlocal complex potential theory. Specific calculations using the effective mass approximation are carried out for electron attachment to CH 3 Cl and CF 3 Cl molecules physisorbed on the surface of a Kr film. The role of image states and image-potential resonances is analyzed. The results show an increase by several orders of magnitude in the cross section for physisorbed molecules as compared with gas-phase molecules. This is in general agreement with the measured cross sections. However, the position of the peak in the cross section for CH 3 Cl is significantly shifted towards higher energies as compared to experiment [K. Nagesha et al., J. Chem. Phys. 114, 4934 (2001)], and the magnitude of the calculated cross section for CF 3 Cl at the surface is significantly higher than the measured value. Possible reasons for disagreements are analyzed

  10. Psychometric properties of the Dissociative Experiences Scale.

    Science.gov (United States)

    Dubester, K A; Braun, B G

    1995-04-01

    The test-retest reliability of the Dissociative Experiences Scale (DES; Bernstein EM, Putnam FW [1986] Development, reliability, and validity of a dissociation scale. The Journal of Nervous and Mental Disease 174:727-735) in a clinical sample was found to be .93 for the total DES score and .95, .89, and .82 for the three subscale scores of amnesia, depersonalization-derealization, and absorption (dissociative identity disorder [DID], DSM-IV), respectively. Test-retest reliabilities within diagnostic groups of multiple personality disorder, dissociative disorder not otherwise specified, and a general other category of psychiatric diagnoses were obtained for total and subscale scores on the DES. These ranged from .78 to .96. Tests of mean scores across the two test sessions showed the total and subscale scores to be temporally stable. The DES was also found to be highly internally consistent: Cronbach's alphas of .96 and .97 were observed for the total DES scores taken at times 1 and 2, respectively. Construct validity of the DES was demonstrated by differentiation among the subscale scores in a repeated-measures analysis of variance (F[2,154] = 32.03, p < or = .001). Normality and general distribution issues were also addressed and provided a rationale for using the DES with parametric statistics. Reasons why the DES (as it was originally designed) is not appropriate as a dependent measure in outcome research are discussed, along with needed future research. Implications of the findings for the clinical usefulness of the DES as a diagnostic instrument are noted.

  11. Process Dissociation and Mixture Signal Detection Theory

    Science.gov (United States)

    DeCarlo, Lawrence T.

    2008-01-01

    The process dissociation procedure was developed in an attempt to separate different processes involved in memory tasks. The procedure naturally lends itself to a formulation within a class of mixture signal detection models. The dual process model is shown to be a special case. The mixture signal detection model is applied to data from a widely…

  12. From dissociated hegemony towards embedded hegemony

    NARCIS (Netherlands)

    Gaay Fortman, B. de; Dhanrajgir, Nikhil

    2005-01-01

    An earlier paper by the second author, entitled ‘Bella Americana: Some Consequences for the International Community’ [1], dealt with the background and consequences of the American dissociation from the international legal and political order created after World War II. The current article

  13. Theory of the dissociation process, ch. 1

    International Nuclear Information System (INIS)

    Asselt, N.P.F.B. van

    1976-01-01

    The formalism of Moeller operators and channel Hamiltonians, originating from scattering theory, is used for the description of the dissociation process. The proper choice of the initial state wave function is discussed. A method is given which accounts for the symmetry requirements which appear in the case of a homonuclear molecule where identical particles are present

  14. Dissociative charge exchange of H2+

    International Nuclear Information System (INIS)

    Bruijn, D. de.

    1983-01-01

    This thesis is devoted to molecular dissociation, in particular the dissociation of the hydrogen molecule H 2 arising from electron capture of its ion H 2 + in a collision. Thereby the important practical question how a chemical bond can be broken is implicitly addressed. This thesis opens (chapter I) with an overview of the available experimental approaches in molecular physics. Further the simple Demkov model for NRCE is described. In chapter II a novel experimental technique for measurements on dissociative processes is introduced which combines a high efficiency with a high energy resolution. A detailed description of the techniques applied in the detector, which has a high spatial and timing resolution with 30 μm and 350 psec FWHM respectively for the detection of one particle, is given in chapter III. A semi-classical theory for NRCE in the medium energy range between a diatomic molecular ion and an atom is developed in chapter IV. The experiments on dissociative charge exchange of H 2 + with Ar, Mg, Na and Cs targets at keV energies are described in Chapter V. The predissociation of the c 3 PIsub(u)-state of H 2 populated after charge exchange of H 2 with several targets at keV energies; is the subject of chapter VI. In chapter VII, orientational oscillations in the cross section for charge exchange of H 2 + with alkali targets are discussed. The last chapter deals with predissociation of highly excited states in H 2 . (Auth.)

  15. CO dissociation on magnetic Fen clusters

    KAUST Repository

    Jedidi, Abdesslem; Markovits, Alexis; Minot, Christian; Abderrabba, Manef Ben; Van Hove, Michel A.

    2014-01-01

    triangular facet of the nanoparticle. Dissociation becomes easier when the cluster size increases. Then, the C atom is bonded to a square facet that is generated as a result of the adsorption if it does not yet exist in the bare cluster, while the O atom

  16. Quarkonium suppression: Gluonic dissociation vs. colour screening

    Indian Academy of Sciences (India)

    mechanism comes into play for the initial conditions taken from the self screened parton cascade model in these studies. Keywords. Quark gluon plasma; J ψ; suppression; dissociation; colour screening. PACS No. 12.38.M. 1. Introduction. The last two decades have seen hectic activity towards identifying unique signatures ...

  17. Dissociative electron attachment to ozone: rate constant

    International Nuclear Information System (INIS)

    Skalny, J.D.; Cicman, P.; Maerk, T.D.

    2002-01-01

    The rate constant for dissociative electron attachment to ozone has been derived over the energy range of 0-10 eV by using previously measured cross section data revisited here in regards to discrimination effect occurring during the extraction of ions. The obtained data for both possible channels exhibit the maximum at mean electron energies close to 1 eV. (author)

  18. Visuomotor Dissociation in Cerebral Scaling of Size

    NARCIS (Netherlands)

    Potgieser, Adriaan R. E.; de Jong, Bauke M.

    2016-01-01

    Estimating size and distance is crucial in effective visuomotor control. The concept of an internal coordinate system implies that visual and motor size parameters are scaled onto a common template. To dissociate perceptual and motor components in such scaling, we performed an fMRI experiment in

  19. Resonances in dissociative recombination: Trends and patterns

    Energy Technology Data Exchange (ETDEWEB)

    Orel, A E; Ngassam, V; Royal, J [Department of Applied Science, University of California, Davis (United States); Roos, J B; Larson, A, E-mail: aeorel@ucdavis.ed [Department of Theoretical Chemistry, Royal Institute of Technology, Stockholm (Sweden)

    2009-11-15

    In dissociative recombination, the kinetic energy of the incident electron is transferred into excitation of the electrons of the target ion and then into kinetic energy of the fragments. In general, this proceeds via a resonance where the electron is temporarily trapped by the ion, leading to efficient energy transfer. The study of dissociative recombination is the study of these resonances, Rydberg states converging to the ground and excited states of the ion. For a number of systems, we have studied the electronic states involved in dissociative recombination, including the ground and excited states of the ion, the resonant states and the bound Rydberg states of the system, by combining electron scattering calculations with multi-reference configuration interaction quantum chemistry calculations. We will report on trends and patterns in these resonance states. We will discuss studies of dissociative recombination of the rare-gas ions, moving down the periodic table from He{sup +}{sub 2} to Ne{sup +}{sub 2} to Ar{sup +}{sub 2}, where the ground electronic state of the ion is constant, but its polarizability increases. We will also present results on isoelectronic polyatomic systems, such as HCO{sup +} and HCNH{sup +}, as well as the effects of changing the electronic structure slightly such as HCN{sup +}/HNC{sup +} and H{sub 2}CO{sup +}.

  20. Dissociation in undergraduate students: disruptions in executive functioning.

    Science.gov (United States)

    Giesbrecht, Timo; Merckelbach, Harald; Geraerts, Elke; Smeets, Ellen

    2004-08-01

    The concept of dissociation refers to disruptions in attentional control. Attentional control is an executive function. Few studies have addressed the link between dissociation and executive functioning. Our study investigated this relationship in a sample of undergraduate students (N = 185) who completed the Dissociative Experiences Scale and the Random Number Generation Task. We found that minor disruptions in executive functioning were related to a subclass of dissociative experiences, notably dissociative amnesia and the Dissociative Experiences Scale Taxon. However, the two other subscales of the Dissociative Experiences Scale, measuring depersonalization and absorption, were unrelated to executive functioning. Our findings suggest that a failure to inhibit previous responses might contribute to the pathological memory manifestations of dissociation.

  1. Combined use of liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) and high performance liquid chromatography with photodiode array detector (HPLC-DAD) in systematic toxicological analysis.

    Science.gov (United States)

    Broecker, Sebastian; Pragst, Fritz; Bakdash, Abdulsallam; Herre, Sieglinde; Tsokos, Michael

    2011-10-10

    Time of flight mass spectrometry provides new possibilities of substance identification by determination of the molecular formula from accurate molecular mass and isotope pattern. However, the huge number of possible isomers requires additional evidence. As a suitable way for routine performance of systematic toxicological analysis, a method for combined use of liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) and high performance liquid chromatography with diode array detector (HPLC-DAD) was developed and applied to blood samples from 77 death cases. The blood samples were prepared by extraction with CH(2)Cl(2) and by protein precipitation with acetonitrile (1:4 (v/v)). The evaporated extracts were reconstituted in 35% acetonitril/0.1% formic acid/H(2)O and aliquots were injected for analysis by LC-QTOF-MS (Agilent 6530) and HPLC-DAD (Agilent 1200). A valve switching system enabled simultaneous operation of both separated chromatographic lines under their respective optimal conditions using the same autosampler. The ESI-QTOF-MS instrument was run in data dependent acquisition mode with switching between MS and MS/MS (cycle time 1.1s) and measuring the full mass spectra and the collision induced dissociation (CID) fragment spectra of all essential [M+H](+) ions. Libraries of accurate mass CID spectra (~2500 substances) and of DAD-UV spectra (~3300 substances) of the authors were used for substance identification. The application of this procedure is demonstrated in detail at four examples with multiple drug intake or administration. In the 77 cases altogether 198 substances were identified (87 by DAD and 195 by QTOF-MS) with a frequency between 1 and 20. In practical application, the sample preparation proved to be suitable for both techniques and for a wide variety of substances with different polarity. The automatic performance of the measurements was efficient and robust. Mutual confirmation, decrease of false positive and

  2. Childhood Traumatic Experiences, Dissociative Symptoms, and Dissociative Disorder Comorbidity Among Patients With Panic Disorder: A Preliminary Study.

    Science.gov (United States)

    Ural, Cenk; Belli, Hasan; Akbudak, Mahir; Tabo, Abdulkadir

    2015-01-01

    This study assessed childhood trauma history, dissociative symptoms, and dissociative disorder comorbidity in patients with panic disorder (PD). A total of 92 psychotropic drug-naive patients with PD, recruited from outpatient clinics in the psychiatry department of a Turkish hospital, were involved in the study. Participants were assessed using the Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D), Dissociation Questionnaire, Panic and Agoraphobia Scale, Panic Disorder Severity Scale, and Childhood Trauma Questionnaire. Of the patients with PD, 18 (19%) had a comorbid dissociative disorder diagnosis on screening with the SCID-D. The most prevalent disorders were dissociative disorder not otherwise specified, dissociative amnesia, and depersonalization disorders. Patients with a high degree of dissociation symptoms and dissociative disorder comorbidity had more severe PD than those without (p dissociation and PD. Among all of the subscales, the strongest relationship was with childhood emotional abuse. Logistic regression analysis showed that emotional abuse and severity of PD were independently associated with dissociative disorder. In our study, a significant proportion of the patients with PD had concurrent diagnoses of dissociative disorder. We conclude that the predominance of PD symptoms at admission should not lead the clinician to overlook the underlying dissociative process and associated traumatic experiences among these patients.

  3. Assessment of complex dissociative disorder patients and simulated dissociation in forensic contexts.

    Science.gov (United States)

    Brand, Bethany L; Webermann, Aliya R; Frankel, A Steven

    Few assessors receive training in assessing dissociation and complex dissociative disorders (DDs). Potential differential diagnoses include anxiety, mood, psychotic, substance use, and personality disorders, as well as exaggeration and malingering. Individuals with DDs typically elevate on many clinical and validity scales on psychological tests, yet research indicates that they can be distinguished from DD simulators. Becoming informed about the testing profiles of DD individuals and DD simulators can improve the accuracy of differential diagnoses in forensic settings. In this paper, we first review the testing profiles of individuals with complex DDs and contrast them with DD simulators on assessment measures used in forensic contexts, including the Minnesota Multiphasic Personality Inventory-2 (MMPI-2), Personality Assessment Inventory (PAI), and the Structured Inventory of Reported Symptoms (SIRS), as well as dissociation-specific measures such as the Dissociative Experiences Scale (DES) and Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D-R). We then provide recommendations for assessing complex trauma and dissociation through the aforementioned assessments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Does phasic trauma treatment make patients with dissociative identity disorder treatment more dissociative?

    Science.gov (United States)

    Brand, Bethany; Loewenstein, Richard J

    2014-01-01

    Proponents of the iatrogenic model of the etiology of dissociative identity disorder (DID) have expressed concern that treatment focused on direct engagement and interaction with dissociated self-states harms DID patients. However, empirical data have shown that this type of DID treatment is beneficial. Analyzing data from the prospective Treatment of Patients With Dissociative Disorders (TOP DD) Study, we test empirically whether DID treatment is associated with clinically adverse manifestations of dissociated self-states: acting so differently that one feels like different people, hearing voices, and dissociative amnesia. We show that, over the course of the study, there were significant decreases in feeling like different people and hearing voices. These results indicate that this form of DID treatment does not lead to symptomatic worsening in these dimensions, as predicted by the iatrogenic model. Indeed, treatment provided by TOP DD therapists reduced, rather than increased, the extent to which patients experienced manifestations of pathological dissociation. Because severe symptomatology and impairment are associated with DID, iatrogenic harm may come from depriving DID patients of treatment that targets DID symptomatology.

  5. Predictors of trait dissociation and peritraumatic dissociation induced via cold pressor.

    Science.gov (United States)

    Gómez-Pérez, Lydia; López-Martínez, Alicia Eva; Asmundson, Gordon John Glenn

    2013-11-30

    Understanding which factors predict individual dissociative response during stressful situations is important to clarify the nature of dissociation and the mechanisms associated to its use as a coping strategy. The present study examined (1) whether experiential avoidance (EA), anxiety sensitivity (AS), depressive symptoms, and state anxiety concurrently predicted trait dissociation (TD)-absorption, amnesia, depersonalization, and total TD scores-and laboratory induced dissociation (LID); and (2) whether TD and catastrophizing predicted LID. We also examined whether catastrophizing mediated the relationships between both AS and depressive symptoms and LID. A total of 101 female undergraduate students participated in a cold pressor task, which significantly induced dissociation. Results of hierarchical regression analyses showed that AS at Time 1 (9 months before the experimental session), as well as depressive symptoms and catastrophizing at the time of the experiment (Time 2), predicted LID at Time 2. Depressive symptoms at Time 2 predicted total TD, absorption, and amnesia scores. AS at Time 1 and depressive symptoms at Time 2 predicted depersonalization. AS, depressive symptoms, and catastrophizing seem to facilitate the use of dissociative strategies by healthy individuals, even in response to non-traumatic but discomforting stress. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  6. The Contribution of Art Therapy to the Dissociative Disorders.

    Science.gov (United States)

    Murphy, Patricia S.

    1994-01-01

    Explored concepts of brain hemispheric lateralization and distinct right brain functioning in extensive dissociation by administering Dissociative Experiences Scale to 114 engineering students and 92 university drawing students. Chi-square calculation found differences in dissociative scoring levels between groups that approached significance at…

  7. The Parenting Experiences of Mothers with Dissociative Disorders.

    Science.gov (United States)

    Benjamin, Lynn R.; Benjamin, Robert; Rind, Bruce

    1998-01-01

    Presents a qualitative analysis of the experience of parenting of mothers with dissociative disorders. Using the mothers' words, describes how the five symptom areas of dissociation impeded their parenting efforts. Discusses the necessity of addressing parenting in the treatment of client-mothers with dissociative disorders. (Author/MKA)

  8. Development, Reliability, and Validity of a Child Dissociation Scale.

    Science.gov (United States)

    Putnam, Frank W.; And Others

    1993-01-01

    Evaluation of the Child Dissociative Checklist found it to be a reliable and valid observer report measure of dissociation in children, including sexually abused girls and children with dissociative disorder and with multiple personality disorder. The checklist, which is appended, is intended as a clinical screening instrument and research measure…

  9. Cognitive Processes in Dissociation: Comment on Giesbrecht et al. (2008)

    Science.gov (United States)

    Bremner, J. Douglas

    2010-01-01

    In their recent review "Cognitive Processes in Dissociation: An Analysis of Core Theoretical Assumptions," published in "Psychological Bulletin", Giesbrecht, Lynn, Lilienfeld, and Merckelbach (2008) have challenged the widely accepted trauma theory of dissociation, which holds that dissociative symptoms are caused by traumatic stress. In doing so,…

  10. Speech-Language Dissociations, Distractibility, and Childhood Stuttering

    Science.gov (United States)

    Conture, Edward G.; Walden, Tedra A.; Lambert, Warren E.

    2015-01-01

    Purpose This study investigated the relation among speech-language dissociations, attentional distractibility, and childhood stuttering. Method Participants were 82 preschool-age children who stutter (CWS) and 120 who do not stutter (CWNS). Correlation-based statistics (Bates, Appelbaum, Salcedo, Saygin, & Pizzamiglio, 2003) identified dissociations across 5 norm-based speech-language subtests. The Behavioral Style Questionnaire Distractibility subscale measured attentional distractibility. Analyses addressed (a) between-groups differences in the number of children exhibiting speech-language dissociations; (b) between-groups distractibility differences; (c) the relation between distractibility and speech-language dissociations; and (d) whether interactions between distractibility and dissociations predicted the frequency of total, stuttered, and nonstuttered disfluencies. Results More preschool-age CWS exhibited speech-language dissociations compared with CWNS, and more boys exhibited dissociations compared with girls. In addition, male CWS were less distractible than female CWS and female CWNS. For CWS, but not CWNS, less distractibility (i.e., greater attention) was associated with more speech-language dissociations. Last, interactions between distractibility and dissociations did not predict speech disfluencies in CWS or CWNS. Conclusions The present findings suggest that for preschool-age CWS, attentional processes are associated with speech-language dissociations. Future investigations are warranted to better understand the directionality of effect of this association (e.g., inefficient attentional processes → speech-language dissociations vs. inefficient attentional processes ← speech-language dissociations). PMID:26126203

  11. Rate coefficients for dissociative attachment and resonant electron-impact dissociation involving vibrationally excited O{sub 2} molecules

    Energy Technology Data Exchange (ETDEWEB)

    Laporta, V. [Istituto di Metodologie Inorganiche e dei Plasmi, CNR, Bari, Italy and Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Celiberto, R. [Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica, Politecnico di Bari, Italy and Istituto di Metodologie Inorganiche e dei Plasmi, CNR, Bari (Italy); Tennyson, J. [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom)

    2014-12-09

    Rate coefficients for dissociative electron attachment and electron-impact dissociation processes, involving vibrationally excited molecular oxygen, are presented. Analytical fits of the calculated numerical data, useful in the applications, are also provided.

  12. AIP Single and double diffraction dissociation at the LHC

    CERN Document Server

    Fiore, Roberto; Mieskolainen, Mikael; Orava, Risto

    2017-01-01

    Single and double di ff raction dissociation at the LHC is studied in a factorizable Regge-pole model, dominated by a Pomeron pole exchange in the t channel. While the contribution from secondary reggeon exchanges at the LHC is negligible, they are indispensable to match the lower-energy, ISR and FNAL data. To this end we append to the leading Pomeron exchange an e ff ective reggeon. The main emphasis in our study is on the nucleon resonances in missing masses, that are accounted for by a dual model of the inelastic pP → M X vertex, similar to the DIS structure function, known from HERA, with a non-linear nucleon, N ∗ trajectory in the direct, M 2 X channel. Regge factorization and its breakdown due to a renormalization factor, tempering the energy rise is discussed.

  13. A theoretical approach to low multiplicity diffractive dissociation

    International Nuclear Information System (INIS)

    Bishari, M.

    1977-01-01

    The dynamics of low mass inelastic diffractive production in the framework of the ''1/N dual unitarization'' scheme are investigated. The smallness of inelastic diffractive dissociation is explicitly demonstrated by incorporating a Deck type mechanism with the crucial planar bootstrap equation. Although both inelastic and elastic pomeron couplings are of the same order in 1/N, the origin for their smallness is not identical. The work further confirms the validity of the iterative procedure, where the elastic amplitude is first generated from only non-diffractive intermediate states (except possibly for central collisions). Using a previous study of the ''Cylinder'' strength, a semi-quantitative results for the integrated cross-section for low multiplicity diffractive production is also presented, and is compared with the elastic cross-section at very high energies. (author)

  14. Diffractive dissociation into 3 pion final states at COMPASS

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Suh-Urk [Technische Universitaet Muenchen, Physik Department E18, 85748 Garching (Germany); Brookhaven National Laboratory, Upton, NY 11973 (United States); Friedrich, Jan; Grabmueller, Stefanie; Haas, Florian; Ketzer, Bernhard; Neubert, Sebastian; Paul, Stephan; Weitzel, Quirin [Technische Universitaet Muenchen, Physik Department E18, 85748 Garching (Germany); Ryabchikov, Dimitry [Technische Universitaet Muenchen, Physik Department E18, 85748 Garching (Germany); Institute for High Energy Physics, 142284 Protvino (Russian Federation)

    2009-07-01

    Diffractive dissociation reactions at the COMPASS experiment, CERN, provide access to the meson resonance spectrum. During a pilot run in 2004, using a pion beam on a lead target, a competitive number of {pi}{sup -} {pi}{sup -} {pi}{sup +} final state events with masses below 2.5 GeV/c{sup 2} were recorded. After COMPASS had finished its muon program in 2007, it used in 2008 again a pion beam, but now a liquid hydrogen target, and gathered during several weeks a unique high statistics. A full partial wave analysis of the 2004 data has been performed, with the focus on the kinematic range of a large momentum transfer (0.1 GeV{sup 2}/c{sup 2} {<=} t' {<=} 1.0 GeV{sup 2}/c{sup 2}). In addition first results of the adjacent analysis with 2008 data are presented.

  15. Diffractive pion dissociation into 5 pion final states at COMPASS

    Energy Technology Data Exchange (ETDEWEB)

    Neubert, Sebastian; Friedrich, Jan; Grabmueller, Stefanie; Haas, Florian; Ketzer, Bernhard; Paul, Stephan; Weitzel, Quirin [Technische Universitaet Muenchen, Physik Department E18, 85748 Garching (Germany); Chung, Suh-Urk [Technische Universitaet Muenchen, Physik Department E18, 85748 Garching (Germany); Brookhaven National Laboratory, Upton, NY 11973 (United States); Ryabchikov, Dimitry [Technische Universitaet Muenchen, Physik Department E18, 85748 Garching (Germany); Institute for High Ernergy Physics, 142284 Protvino (Russian Federation)

    2009-07-01

    COMPASS is a fixed-target experiment at the CERN SPS, which investigates the structure and spectroscopy of hadrons. In 2004, a first run with a 190 GeV/c {pi}{sup -} beam took place using nuclear targets. Diffractive dissociation reactions observed in this run provide clean access to meson resonances with masses up to 3 GeV/c{sup 2}. Exclusive final states with 5 charged pions have been extracted. The covered range in momentum transfer extends from threshold to a few GeV{sup 2}/c{sup 2} allowing to study resonance production in different regimes. We report on the status of the analysis of this unique data set.

  16. Comparing the symptoms and mechanisms of "dissociation" in dissociative identity disorder and borderline personality disorder.

    Science.gov (United States)

    Laddis, Andreas; Dell, Paul F; Korzekwa, Marilyn

    2017-01-01

    A total of 75 patients were diagnosed with the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised as having dissociative identity disorder (DID), and 100 patients were diagnosed with the Structured Interview for DSM-IV Personality as having borderline personality disorder (BPD). Both groups were administered the Multidimensional Inventory of Dissociation (MID). DID patients had significantly higher MID scores than BPD patients, different distributions of MID scores, and different MID subscale profiles in 3 ranges of MID scores (0-15, 15-30, 30-45). The core MID symptoms-exhibited at all ranges of MID scores-for DID patients (the presence of alters, identity confusion, and memory problems) and BPD patients (flashbacks, identity confusion, and memory problems) were ostensibly similar but were considered to be mostly produced by different underlying processes. Multiple regression analyses showed that the core MID symptoms of DID patients had different predictors than did the core MID symptoms of BPD patients. Alter identities seemed to generate most-but not all-dissociative phenomena in DID patients, whereas only the 24% highest scoring BPD patients (MID ≥45) seemed to manifest alter-driven dissociative experiences. Most BPD dissociative experiences appeared to be due to 5 other mechanisms: (a) BPD-specific, stress-driven, rapid shifts of self-state; (b and c) nondefensive disruptions of the framework of perceptual organization with or without an accompanying BPD-specific, dissociation-like disintegration of affective/neurocognitive functioning; (d) a defensive distancing or detachment from distress (i.e., simple depersonalization); and (e) Allen, Console, and Lewis's (1999) severe absorptive detachment.

  17. Elastic and Proton-Dissociative Photoproduction of J/psi Mesons at HERA

    CERN Document Server

    Alexa, C.; Baghdasaryan, A.; Baghdasaryan, S.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Boudry, V.; Bozovic-Jelisavcic, I.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Buniatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Chekelian, V.; Contreras, J.G.; Cvach, J.; Dainton, J.B.; Daum, K.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Eckerlin, G.; Egli, S.; Elsen, E.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Habib, S.; Haidt, D.; Henderson, R.C.W.; Hennekemper, E.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hladky, J.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, H.; Kapichine, M.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kogler, R.; Kostka, P.; Kramer, M.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Laycock, P.; Lebedev, A.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Lopez-Fernandez, R.; Lubimov, V.; Malinovski, E.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Morozov, A.; Morris, J.V.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Palichik, V.; Pandurovic, M.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shushkevich, S.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sykora, T.; Thompson, P.D.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zlebcik, R.; Zohrabyan, H.; Zomer, F.

    2013-06-15

    Cross sections for elastic and proton-dissociative photoproduction of J/psi mesons are measured with the H1 detector in positron-proton collisions at HERA. The data were collected at $ep$ centre-of-mass energies sqrt{s} approx 318 GeV and sqrt{s} approx 225 GeV, corresponding to integrated luminosities of L = 130 pb^{-1} and L = 10.8 pb^{-1}, respectively. The cross sections are measured as a function of the photon-proton centre-of-mass energy in the range 25< Wgp < 110 GeV. Differential cross sections $\\mathrm{d}\\sigma / \\mathrm{d}t$, where $t$ is the squared four-momentum transfer at the proton vertex, are measured in the range $|t| < 1.2 \\, \\gevsq$ for the elastic process and $|t| < 8 \\, \\gevsq$ for proton dissociation. The results are compared to other measurements. The $\\Wgp$ and $t$-dependences are parametrised using phenomenological fits.

  18. Elastic and proton-dissociative photoproduction of J/ψ mesons at HERA

    International Nuclear Information System (INIS)

    Alexa, C.; Dobre, M.; Rotaru, M.; Stoicea, G.; Andreev, V.; Belousov, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Vazdik, Y.; Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H.; Bartel, W.; Belov, P.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Habib, S.; Haidt, D.; Kleinwort, C.; Kraemer, M.; Krueger, K.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Boudry, V.; Specka, A.; Bozovic-Jelisavcic, I.; Pandurovic, M.; Brandt, G.; Brisson, V.; Jacquet, M.; Pascaud, C.; Zhang, Z.; Zomer, F.; Buniatyan, A.; Huber, F.; Pirumov, H.; Sauter, M.; Schoening, A.; Bylinkin, A.; Bystritskaya, L.; Fedotov, A.; Lubimov, V.; Rostovtsev, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Ceccopieri, F.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Roosen, R.; Staykova, Z.; Mechelen, P. van; Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R.; Chekelian, V.; Grindhammer, G.; Kiesling, C.; Cvach, J.; Hladky, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Daum, K.; Meyer, H.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C.; Dodonov, V.; Dossanov, A.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Feltesse, J.; Perez, E.; Schoeffel, L.; Ferencei, J.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Grab, C.; Henderson, R.C.W.; Hennekemper, E.; Herbst, M.; Schultz-Coulon, H.C.; Herrera, G.; Lopez-Fernandez, R.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Joensson, L.; Jung, H.; Kapichine, M.; Morozov, A.; Nikitin, D.; Palichik, V.; Spaskov, V.; Kogler, R.; Nowak, K.; Landon, M.P.J.; Rizvi, E.; Traynor, D.; Martyn, H.U.; Morris, J.V.; Sankey, D.P.C.; Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P.; Newman, P.R.; Thompson, P.D.; Picuric, I.; Raicevic, N.; Soloviev, Y.; Stella, B.; Sykora, T.; Tsakov, I.; Wegener, D.

    2013-01-01

    Cross sections for elastic and proton-dissociative photoproduction of J/ψ mesons are measured with the H1 detector in positron-proton collisions at HERA. The data were collected at ep centre-of-mass energies √(s) ∼ 318 GeV and √(s) ∼ 225 GeV, corresponding to integrated luminosities of L = 130 pb -1 and L = 10.8 pb -1 , respectively. The cross sections are measured as a function of the photon-proton centre-of-mass energy in the range 25 γp 2 for the elastic process and vertical stroke t vertical stroke 2 for proton dissociation. The results are compared to other measurements. The W γp and t-dependences are parametrised using phenomenological fits. (orig.)

  19. Grammatical category dissociation in multilingual aphasia.

    Science.gov (United States)

    Faroqi-Shah, Yasmeen; Waked, Arifi N

    2010-03-01

    Word retrieval deficits for specific grammatical categories, such as verbs versus nouns, occur as a consequence of brain damage. Such deficits are informative about the nature of lexical organization in the human brain. This study examined retrieval of grammatical categories across three languages in a trilingual person with aphasia who spoke Arabic, French, and English. In order to delineate the nature of word production difficulty, comprehension was tested, and a variety of concomitant lexical-semantic variables were analysed. The patient demonstrated a consistent noun-verb dissociation in picture naming and narrative speech, with severely impaired production of verbs across all three languages. The cross-linguistically similar noun-verb dissociation, coupled with little evidence of semantic impairment, suggests that (a) the patient has a true "nonsemantic" grammatical category specific deficit, and (b) lexical organization in multilingual speakers shares grammatical class information between languages. The findings of this study contribute to our understanding of the architecture of lexical organization in bilinguals.

  20. P300 is attenuated during dissociative episodes.

    Science.gov (United States)

    Kirino, Eiji

    2006-02-01

    The present study examined the pathophysiology of dissociative phenomena using the P300 component of event-related potentials, quantitative electroencephalography (QEEG), and morphology measures of computed tomography scan. Event-related potentials during an auditory oddball paradigm and QEEG in resting state were recorded. Patients exhibited attenuation of P300 amplitudes compared with controls during dissociative episodes, but exhibited recovery to control levels in remission. Patients had a larger Sylvian fissure-brain ratio than did controls. QEEG findings revealed no significant differences between the patients and controls or between episodes and remission in the patient group. Attenuation of the P300 can be interpreted as the result of a negative feedback loop from the medial temporal lobe to the cortex, which decreases the amount of information flow, allocation of attentional resources, and updating of working memory to avoid both excessive long-term memory system activity in medial temporal lobe and resurgence of affect-laden memories.

  1. Dissociative Disorders: Between Neurosis and Psychosis

    Science.gov (United States)

    Devillé, C.; Moeglin, C.; Sentissi, O.

    2014-01-01

    Dissociative disorders are a set of disorders defined by a disturbance affecting functions that are normally integrated with a prevalence of 2.4 percent in industrialised countries. These disorders are often poorly diagnosed or misdiagnosed because of sharing common clinical features with psychotic disorders, but requiring a very different trajectory of care. Repeated clinical situations in a crisis centre in Geneva provided us with a critical overview of current evidence of knowledge in clinical and etiopathological field about dissociative disorders. Because of their multiple expressions and the overlap with psychotic disorders, we focused on the clinical aspects using three different situations to better understand their specificity and to extend our thinking to the relevance of terms “neurosis” and “psychosis.” Finally, we hope that this work might help physicians and psychiatrists to become more aware of this complex set of disorders while making a diagnosis. PMID:25405051

  2. Dissociative Disorders: Between Neurosis and Psychosis

    Directory of Open Access Journals (Sweden)

    C. Devillé

    2014-01-01

    Full Text Available Dissociative disorders are a set of disorders defined by a disturbance affecting functions that are normally integrated with a prevalence of 2.4 percent in industrialised countries. These disorders are often poorly diagnosed or misdiagnosed because of sharing common clinical features with psychotic disorders, but requiring a very different trajectory of care. Repeated clinical situations in a crisis centre in Geneva provided us with a critical overview of current evidence of knowledge in clinical and etiopathological field about dissociative disorders. Because of their multiple expressions and the overlap with psychotic disorders, we focused on the clinical aspects using three different situations to better understand their specificity and to extend our thinking to the relevance of terms “neurosis” and “psychosis.” Finally, we hope that this work might help physicians and psychiatrists to become more aware of this complex set of disorders while making a diagnosis.

  3. Critical superheats upon boiling of dissociating liquids

    International Nuclear Information System (INIS)

    Kolykhan, L.I.; Solov'ev, V.N.

    1985-01-01

    The experimental data on critical superheats of dissociating liquids, i.e. nitrogen tetroxide and nitrine are presented (nitrine is the solution of nitrogen oxide in nitrogen tetroxide). The experiments with boiling N 2 O 4 have been carried out in the pressure range 0.1-3.0 MPa and with boiling nitrine within the pressure range 0.2-9.0 MPa. The experiments have revealed an anomalous dependence of critical superheats on pressure P, thus at P>=2.5 MPa the critical superheat values exceed the limiting ones, and at P=4.5 MPa this excess amounts to more than 16 K, essentially exceeding the errors of the experiments. The results for N 2 O 4 critical superheats agree with experimental data of other authors. Complex phenomena observed upon boiling of dissociating liquids require further theoretical and experimental studies

  4. Photon diffractive dissociation in deep inelastic scattering

    International Nuclear Information System (INIS)

    Ryskin, M.G.

    1990-01-01

    The new ep-collider HERA gives us the possibility to study the diffractive dissociation of virtual photon in deep inelastic ep-collision. The process of photon dissociation in deep inelastic scattering is the most direct way to measure the value of triple-pomeron vertex G 3P . It was shown that the value of the correct bare vertex G 3P may more than 4 times exceeds its effective value measuring in the triple-reggeon region and reaches the value of about 40-50% of the elastic pp-pomeron vertex. On the contrary in deep inelastic processes the perpendicular momenta q t of the secondary particles are large enough. Thus in deep inelastic reactions one can measure the absolute value of G 3P vertex in the most direct way and compare its value and q t dependence with the leading log QCD predictions

  5. Dissociative Excitation of Thymine by Electron Impact

    Science.gov (United States)

    McConkey, William; Tiessen, Collin; Hein, Jeffrey; Trocchi, Joshuah; Kedzierski, Wladek

    2014-05-01

    A crossed electron-gas beam system coupled to a VUV spectrometer has been used to investigate the dissociation of thymine (C5H6N2O2) into excited atomic fragments in the electron-impact energy range from threshold to 375 eV. A special stainless steel oven is used to vaporize the thymine and form it into a beam where it is intersected by a magnetically collimated electron beam, typical current 50 μA. The main features in the spectrum are the H Lyman series lines. The probability of extracting excited C or N atoms from the ring is shown to be very small. In addition to spectral data, excitation probability curves as a function of electron energy will be presented for the main emission features. Possible dissociation channels and excitation mechanisms in the parent molecule will be discussed. The authors thank NSERC (Canada) for financial support.

  6. Dissociative Disorders Among Chinese Inpatients Diagnosed With Schizophrenia

    Science.gov (United States)

    Yu, Junhan; Ross, Colin A.; Keyes, Benjamin B.; Li, Ying; Dai, Yunfei; Zhang, Tianhong; Wang, Lanlan; Fan, Qing; Xiao, Zeping

    2010-01-01

    The purpose of the study was to assess the prevalence of dissociative disorders in a sample of Chinese psychiatric inpatients. Participants in the study consisted of 569 consecutively admitted inpatients at Shanghai Mental Health Center, China, of whom 84.9% had a clinical diagnosis of schizophrenia based on the Chinese Classification and Diagnostic Criteria for Mental Disorders, Version 3 (CCMD-3). All participants completed a self-report measure of dissociation, the Dissociative Experiences Scale (DES) and none had a prior diagnosis of a dissociative disorder. Ninety-six randomly selected participants were interviewed with a structured interview, the Dissociative Disorders Interview Schedule (DDIS) and a clinical interview. These 96 patients did not differ significantly from the 473 patients who were not interviewed on any demographic measures or on the self-report measure dissociation. A total of 28 (15.3%, after weighting of the data) patients received a clinical diagnosis of a dissociative disorder based on DSM-IV-TR criteria. Dissociative identity disorder was diagnosed in 2 (0.53%, after weighting) patients. Compared to the patients without a dissociative disorder, patients with dissociative disorders were significantly more likely to report childhood abuse (57.1% versus 22.1%), but the two groups did not differ significantly on any demographic measures. Dissociative disorders were readily identified in an inpatient psychiatric population in China. PMID:20603768

  7. Search for the H Dibaryon (S = -2) Using Diffraction Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Ecklund, K.

    2005-04-05

    The observed hadrons are understood as bound states of three quarks (baryons) or of quarks and antiquarks (mesons). To date no six quark bound state other than the loosely bound deuteron has been observed. Quantum Chromodynamics permits other color-singlet bound states of quarks, and a number of phenomenological models extended from the baryon (q{sup 3}) and meson (q{bar q}) sectors predict bound six quark states (q{sup 6}). The most probable candidate is the H dibaryon, composed of two each of the lightest three quarks (udsuds), with quantum numbers J{sup P} = 0{sup +}, I = 0 and S = -2. Its mass would likely be between the deuteron mass and twice the {Lambda} (uds) mass. This dissertation describes a search for the H dibaryon conducted in a neutral beam at the Brookhaven National Laboratory's Alternating Gradient Synchrotron. In the experiment a 24.1 GeV/c proton beam struck a 1.35 interaction length platinum target producing a collimated neutral beam (62 {mu}sr at 65 mrad from the incident proton direction) which propagated through a 18 m vacuum decay tank before entering a double arm spectrometer. Approximately 20 m from the production target a 10 cm (0.15 interaction length) long active scintillator dissociator was placed in the beam.

  8. Malingering dissociative identity disorder: objective and projective assessment.

    Science.gov (United States)

    Labott, Susan M; Wallach, Heather R

    2002-04-01

    Verification of dissociative identity disorder presents challenges given the complex nature of the illness. This study addressed the concern that this disorder can be successfully malingered on objective and projective psychological tests. 50 undergraduate women were assigned to a Malingering or a Control condition, then completed the Rorschach Inkblot Test and the Dissociative Experiences Scale II. The Malingering group were asked to simulate dissociative identity disorder; controls received instructions to answer all materials honestly. Analysis indicated that malingerers were significantly more likely to endorse dissociative experiences on the Dissociative Experiences Scale II in the range common to patients with diagnosed dissociative identity disorder. However, on the Rorschach there were no significant differences between the two groups. Results suggest that the assessment of dissociative identity disorder requires a multifaceted approach with both objective and projective assessment tools. Research is needed to assess these issues in clinical populations.

  9. Teaching Chinese psychiatrists to make reliable dissociative disorder diagnoses.

    Science.gov (United States)

    Fan, Qing; Yu, Junhan; Ross, Colin A; Keyes, Benjamin B; Dai, Yunfei; Zhang, Tianhong; Wang, Lanlan; Xiao, Zeping

    2011-09-01

    The aim of the study was to assess the outcome of an educational effort by two North American experts in dissociative disorders to teach Chinese psychiatrists to make reliable dissociative disorder diagnoses. In the final phase of the educational effort, 569 patients at Shanghai Mental Health Center completed the Chinese version of the Dissociative Experiences Scale (DES). Patients were then randomly selected in different proportions according to their DES scores: 96 selected patients were then assessed with the Dissociative Disorders Interview Schedule (DDIS) and clinical diagnostic interviews based on DSM-IV criteria. According to the clinical diagnostic interviews, 28 (4.9%) patients were diagnosed as having dissociative disorders. Agreement between the American experts and Chinese psychiatrists for presence or absence of a dissociative disorder was 0.75 using Cohen's kappa. Dissociative disorders can be diagnosed in China with good inter-rater reliability. The authors describe the steps taken to achieve this outcome.

  10. Total dissociation cross section of halo nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Formanek, J. [Karlova Univ., Prague (Czech Republic). Fakulta Matematicko-Fyzikalni; Lombard, R.J. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire

    1996-10-01

    Calculations of the total dissociation cross section is performed in the impact parameter representation. The case of {sup 11}Be and {sup 11}Li loosing one and two neutron(s), respectively, by collision on a {sup 12}C target, which remains in its ground state are discussed. The results are found to depend essentially on the rms radius of the halo wave function. (author). 12 refs.

  11. Coulomb dissociation studies for astrophysical thermonuclear reactions

    Energy Technology Data Exchange (ETDEWEB)

    Motobayashi, T [Dept. of Physics, Rikkyo Univ., Toshima, Tokyo (Japan)

    1998-06-01

    The Coulomb dissociation method was applied to several radiative capture processes of astrophysical interest. The method has an advantage of high experimental efficiency, which allow measurements with radioactive nuclear beams. The reactions {sup 13}N(p,{gamma}){sup 14}O and {sup 7}Be(p,{gamma}){sup 8}B are mainly discussed. They are the key reaction in the hot CNO cycle in massive stars and the one closely related to the solar neutrino problem, respectively. (orig.)

  12. Dressing effect in multiphoton unimolecular dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Diaz, P.F.; Garcia-Fernandez, P.

    1986-03-01

    On the basis of a quantum-statistical model recently discussed, we deal in this paper with the perturbations induced by the intense field of a CO/sub 2/ laser on the levels of the vibrational pattern of a molecule undergoing multiphoton unimolecular dissociation. This perturbational correction is investigated by using a displacement operator technique and the results are interpreted according to the statistical model.

  13. Attempting to model dissociations of memory.

    Science.gov (United States)

    Reber, Paul J.

    2002-05-01

    Kinder and Shanks report simulations aimed at describing a single-system model of the dissociation between declarative and non-declarative memory. This model attempts to capture both Artificial Grammar Learning (AGL) and recognition memory with a single underlying representation. However, the model fails to reflect an essential feature of recognition memory - that it occurs after a single exposure - and the simulations may instead describe a potentially interesting property of over-training non-declarative memory.

  14. Rapid screening of N-oxides of chemical warfare agents degradation products by ESI-tandem mass spectrometry.

    Science.gov (United States)

    Sridhar, L; Karthikraj, R; Lakshmi, V V S; Raju, N Prasada; Prabhakar, S

    2014-08-01

    Rapid detection and identification of chemical warfare agents and related precursors/degradation products in various environmental matrices is of paramount importance for verification of standards set by the chemical weapons convention (CWC). Nitrogen mustards, N,N-dialkylaminoethyl-2-chlorides, N,N-dialkylaminoethanols, N-alkyldiethanolamines, and triethanolamine, which are listed CWC scheduled chemicals, are prone to undergo N-oxidation in environmental matrices or during decontamination process. Thus, screening of the oxidized products of these compounds is also an important task in the verification process because the presence of these products reveals alleged use of nitrogen mustards or precursors of VX compounds. The N-oxides of aminoethanols and aminoethylchlorides easily produce [M + H](+) ions under electrospray ionization conditions, and their collision-induced dissociation spectra include a specific neutral loss of 48 u (OH + CH2OH) and 66 u (OH + CH2Cl), respectively. Based on this specific fragmentation, a rapid screening method was developed for screening of the N-oxides by applying neutral loss scan technique. The method was validated and the applicability of the method was demonstrated by analyzing positive and negative samples. The method was useful in the detection of N-oxides of aminoethanols and aminoethylchlorides in environmental matrices at trace levels (LOD, up to 500 ppb), even in the presence of complex masking agents, without the use of time-consuming sample preparation methods and chromatographic steps. This method is advantageous for the off-site verification program and also for participation in official proficiency tests conducted by the Organization for the Prohibition of Chemical Weapons (OPCW), the Netherlands. The structure of N-oxides can be confirmed by the MS/MS experiments on the detected peaks. A liquid chromatography-mass spectrometry (LC-MS) method was developed for the separation of isomeric N-oxides of aminoethanols and

  15. How thioredoxin dissociates its mixed disulfide.

    Directory of Open Access Journals (Sweden)

    Goedele Roos

    2009-08-01

    Full Text Available The dissociation mechanism of the thioredoxin (Trx mixed disulfide complexes is unknown and has been debated for more than twenty years. Specifically, opposing arguments for the activation of the nucleophilic cysteine as a thiolate during the dissociation of the complex have been put forward. As a key model, the complex between Trx and its endogenous substrate, arsenate reductase (ArsC, was used. In this structure, a Cys29(Trx-Cys89(ArsC intermediate disulfide is formed by the nucleophilic attack of Cys29(Trx on the exposed Cys82(ArsC-Cys89(ArsC in oxidized ArsC. With theoretical reactivity analysis, molecular dynamics simulations, and biochemical complex formation experiments with Cys-mutants, Trx mixed disulfide dissociation was studied. We observed that the conformational changes around the intermediate disulfide bring Cys32(Trx in contact with Cys29(Trx. Cys32(Trx is activated for its nucleophilic attack by hydrogen bonds, and Cys32(Trx is found to be more reactive than Cys82(ArsC. Additionally, Cys32(Trx directs its nucleophilic attack on the more susceptible Cys29(Trx and not on Cys89(ArsC. This multidisciplinary approach provides fresh insights into a universal thiol/disulfide exchange reaction mechanism that results in reduced substrate and oxidized Trx.

  16. Dissociative recombination of small molecular ions

    International Nuclear Information System (INIS)

    Mul, P.M.

    1981-01-01

    In this thesis an analysis is given of merged electron-ion beam experiment and work on dissociative recombination of molecular ions and electrons is described. Chapter II covers a brief introduction of the theory of dissociative recombination. In chapter III, a description is given of the merged electron-ion beam experiment and a method is described which allows the determination of the mean angle between the electron and ion trajectories in a merged electron-ion beam experiment. In chapter IV a paper on the three dominant atmospheric diatomic ions NO + , O 2 + and N 2 + is presented and in chapter V the dissociative recombination for N 2 H + and N 2 D + is discussed. In chapter VI two papers on the polyatomic ions of the carbon-containing molecular ions are presented, and in chapter VII a letter with some results of the work presented in more detail in the chapters IV, V and VI is presented. The magnitude and the energy dependence of the cross-section measured by the merged beam technique and by other techniques is compared and discussed. (Auth.)

  17. Dissociated cultures of newborn mouse brain

    International Nuclear Information System (INIS)

    Wiesmann, U.N.; Hofmann, K.; Burkhart, T.; Herschkowitz, N.

    1975-01-01

    The metabolism of 35 SO 4 -sulfated lipids and mucopolysaccharides was studied in dissociated brain cell cultures from newborn albino mouse brains. The cultures were maintained under an atmosphere of 40% O 2 and 5% CO 2 in apparent good health up to 30 days. Early morphological examination of the dissociated cells demonstrated an initial partial reaggregation of the cells, which later settled and became confluent bilayered cultures. Cell proliferation measured by DNA and protein determination, morphological differentiation and biochemical differentiation took place in the dissociated brain cell cultures analogous in some respects to the in vivo situation. A timed increase in the synthesis of a myelin precursor, cerebroside 35 SO 4 , was observed after 6 to 8 days in culture (DIC). A peak of cerebroside sulfate was evident at 17 DIC. No stable sulfatide was observed at any time. Protein-bound macromolecular 35 SO 4 -MPS was synthetized and secreted from the cells into the culture medium. Maximal synthesis and secretion occurred at 8 DIC. This culture system proves to be a useful model for studying some aspects of differentiation of brain cells under external conditions. (author)

  18. Origin of Asymmetric Charge Partitioning in the Dissociation of Gas-Phase Protein Homodimers

    OpenAIRE

    Jurchen, John C.; Williams, Evan R.

    2003-01-01

    The origin of asymmetric charge and mass partitioning observed for gas-phase dissociation of multiply charged macromolecular complexes has been hotly debated. These experiments hold the potential to provide detailed information about the interactions between the macromolecules within the complex. Here, this unusual phenomenon of asymmetric charge partitioning is investigated for several protein homodimers. Asymmetric charge partitioning in these ions depends on a number of factors, including ...

  19. Dynamics of gas-phase transient species studied by dissociative photodetachment of molecular anions

    OpenAIRE

    Lu, Zhou

    2007-01-01

    Gas-phase transient species, such as the CH₃CO₂ and HOCO free radicals, play important roles in combustion and environment chemistry. In this thesis work, the dynamics of these two radicals were studied by dissociative photodetachment (DPD) of the negative ions, CH₃CO₂-С and HOCO⁻, respectively. The experiments were carried out with a fast-ion-beam photoelectron-photofragment coincidence (PPC) spectrometer. Mass-selected molecular anions in a fast ion beam were intercepted by a linearly polar...

  20. [Questionnaire on dissociative symptoms. German adaptation, reliability and validity of the American Dissociative Experience Scale (DES)].

    Science.gov (United States)

    Freyberger, H J; Spitzer, C; Stieglitz, R D; Kuhn, G; Magdeburg, N; Bernstein-Carlson, E

    1998-06-01

    The "Fragebogen zu dissoziativen Symptomen (FDS)" represents the authorised German translation and adaptation of the "Dissociative Experience Scale" (DES; Bernstein and Putnam 1986). The original scale comprises 28 items covering dissociative experiences with regard to memory, identity, awareness and cognition according to DSM-III-R and DSM-IV. For the German version, 16 items were added to cover dissociative phenomena according to ICD-10, mainly pseudoneurological conversion symptoms. Reliability and validity of the German version were studied in a total sample of 813 persons and were compared to the results of the original version. Test-retest reliability of the FDS was rtt = 0.88 and Cronbach's consistency coefficient was alpha = 0.93, which is comparable to the results of the DES. The instrument differentiates between different samples (healthy control subjects, students, unselected neurological and psychiatric inpatients, neurological and psychiatric patients with a dissociative disorder and schizophrenics). The FDS is an easily applicable, reliable and valid measure to quantify dissociative experiences.

  1. Zero-Point Energy Constraint for Unimolecular Dissociation Reactions. Giving Trajectories Multiple Chances To Dissociate Correctly.

    Science.gov (United States)

    Paul, Amit K; Hase, William L

    2016-01-28

    A zero-point energy (ZPE) constraint model is proposed for classical trajectory simulations of unimolecular decomposition and applied to CH4* → H + CH3 decomposition. With this model trajectories are not allowed to dissociate unless they have ZPE in the CH3 product. If not, they are returned to the CH4* region of phase space and, if necessary, given additional opportunities to dissociate with ZPE. The lifetime for dissociation of an individual trajectory is the time it takes to dissociate with ZPE in CH3, including multiple possible returns to CH4*. With this ZPE constraint the dissociation of CH4* is exponential in time as expected for intrinsic RRKM dynamics and the resulting rate constant is in good agreement with the harmonic quantum value of RRKM theory. In contrast, a model that discards trajectories without ZPE in the reaction products gives a CH4* → H + CH3 rate constant that agrees with the classical and not quantum RRKM value. The rate constant for the purely classical simulation indicates that anharmonicity may be important and the rate constant from the ZPE constrained classical trajectory simulation may not represent the complete anharmonicity of the RRKM quantum dynamics. The ZPE constraint model proposed here is compared with previous models for restricting ZPE flow in intramolecular dynamics, and connecting product and reactant/product quantum energy levels in chemical dynamics simulations.

  2. Dissociative symptoms and dissociative disorders comorbidity in obsessive compulsive disorder: Symptom screening, diagnostic tools and reflections on treatment.

    Science.gov (United States)

    Belli, Hasan

    2014-08-16

    Borderline personality disorder, conversion disorder and obsessive compulsive disorder frequently have dissociative symptoms. The literature has demonstrated that the level of dissociation might be correlated with the severity of obsessive compulsive disorder (OCD) and that those not responding to treatment had high dissociative symptoms. The structured clinical interview for DSM-IV dissociative disorders, dissociation questionnaire, somatoform dissociation questionnaire and dissociative experiences scale can be used for screening dissociative symptoms and detecting dissociative disorders in patients with OCD. However, a history of neglect and abuse during childhood is linked to a risk factor in the pathogenesis of dissociative psychopathology in adults. The childhood trauma questionnaire-53 and childhood trauma questionnaire-40 can be used for this purpose. Clinicians should not fail to notice the hidden dissociative symptoms and childhood traumatic experiences in OCD cases with severe symptoms that are resistant to treatment. Symptom screening and diagnostic tools used for this purpose should be known. Knowing how to treat these pathologies in patients who are diagnosed with OCD can be crucial.

  3. Profiling of ornithine lipids in bacterial extracts of Rhodobacter sphaeroides by reversed-phase liquid chromatography with electrospray ionization and multistage mass spectrometry (RPLC-ESI-MS(n)).

    Science.gov (United States)

    Granafei, Sara; Losito, Ilario; Trotta, Massimo; Italiano, Francesca; de Leo, Vincenzo; Agostiano, Angela; Palmisano, Francesco; Cataldi, Tommaso R I

    2016-01-15

    Ornithine lipids (OLs), a sub-group of the large (and of emerging interest) family of lipoamino acids of bacterial origin, contain a 3-hydroxy fatty acyl chain linked via an amide bond to the α-amino group of ornithine and via an ester bond to a second fatty acyl chain. OLs in extracts of Rhodobacter sphaeroides (R. sphaeroides) were investigated by high-performance reversed phase liquid chromatography (RPLC) with electrospray ionization mass spectrometry (ESI-MS) in negative ion mode using a linear ion trap (LIT). The presence of OLs bearing both saturated (i.e, 16:0, 17:0, 18:0, 19:0 and 20:0) and unsaturated chains (i.e., 18:1, 19:1, 19:2 and 20:1) was ascertained and their identification, even for isomeric, low abundance and partially co-eluting species, was achieved by low-energy collision induced dissociation (CID) multistage mass spectrometry (MS(n), n = 2-4). OLs signatures found in two R. sphaeroides strains, i.e., wild type 2.4.1 and mutant R26, were examined and up to 16 and 17 different OL species were successfully identified, respectively. OLs in both bacterial strains were characterized by several combinations of fatty chains on ester-linked and amide-linked 3-OH fatty acids. Multistage MS spectra of monoenoic amide-linked 3-OH acyl chains, allowed the identification of positional isomer of OL containing 18:1 (i.e. 9-octadecenoic) and 20:1 (i.e. 11-eicosenoic) fatty acids. The most abundant OL ([M-H](-) at m/z 717.5) in R. sphaeroides R26 was identified as OL 3-OH 20:1/19:1 (i.e., 3-OH-eicosenoic acid amide-linked to ornithine and esterified to a nonadecenoic chain containing a cyclopropane ring). An unusual OL (m/z 689.5 for the [M-H](-) ion), most likely containing a cyclopropene ester-linked acyl chain (i.e., OL 3-OH 18:0/19:2), was retrieved only in the carotenoidless mutant strain R26. Based on the biosynthetic pathways already known for cyclopropa(e)ne ring-including acyl chains, a plausible explanation was invoked for the enzymatic

  4. Dissociation and memory fragmentation in post-traumatic stress disorder: an evaluation of the dissociative encoding hypothesis.

    Science.gov (United States)

    Bedard-Gilligan, Michele; Zoellner, Lori A

    2012-01-01

    Several prominent theories of post-traumatic stress disorder (PTSD) posit that peritraumatic dissociation results in insufficient encoding of the trauma memory and that persistent dissociation prevents memory elaboration, resulting in memory fragmentation and PTSD. In this review we summarise the empirical literature on peritraumatic and trait dissociation and trauma narrative fragmentation as measured by meta-memory and rater/objective coding. Across 16 studies to date, the association between dissociation and fragmentation was most prominent when examining peritraumatic dissociation and patient's own ratings of memory fragmentation. This relationship did not hold when examining trait dissociation or rater-coded or computer-generated measures of fragmentation. Thus initial evidence points more towards a strong self-reported association between constructs that is not supported on more objective fragmentation coding. Measurement overlap, construct ambiguity, and exclusion of potential confounds may underlie lack of a strong association between dissociation and objective-rated fragmentation.

  5. Sequencing Larger Intact Proteins (30-70 kDa) with Activated Ion Electron Transfer Dissociation

    Science.gov (United States)

    Riley, Nicholas M.; Westphall, Michael S.; Coon, Joshua J.

    2018-01-01

    The analysis of intact proteins via mass spectrometry can offer several benefits to proteome characterization, although the majority of top-down experiments focus on proteoforms in a relatively low mass range (AI-ETD) to proteins in the 30-70 kDa range. AI-ETD leverages infrared photo-activation concurrent to ETD reactions to improve sequence-informative product ion generation. This method generates more product ions and greater sequence coverage than conventional ETD, higher-energy collisional dissociation (HCD), and ETD combined with supplemental HCD activation (EThcD). Importantly, AI-ETD provides the most thorough protein characterization for every precursor ion charge state investigated in this study, making it suitable as a universal fragmentation method in top-down experiments. Additionally, we highlight several acquisition strategies that can benefit characterization of larger proteins with AI-ETD, including combination of spectra from multiple ETD reaction times for a given precursor ion, multiple spectral acquisitions of the same precursor ion, and combination of spectra from two different dissociation methods (e.g., AI-ETD and HCD). In all, AI-ETD shows great promise as a method for dissociating larger intact protein ions as top-down proteomics continues to advance into larger mass ranges. [Figure not available: see fulltext.

  6. Dissociation of 1P states in hot QCD Medium Using Quasi-Particle Model

    Science.gov (United States)

    Nilima, Indrani; Agotiya, Vineet Kumar

    2018-03-01

    We extend the analysis of a very recent work [1] to study the dissociation phenomenon of 1P states of the charmonium and bottomonium spectra (χc and χb) in a hot QCD medium using Quasi-Particle Model. This study employed a medium modified heavy quark potential which has quite different form in the sense that it has a lomg range Coulombic tail in addition to the Yukawa term even above the deconfinement temperature. Then we study the flavor dependence of their binding energies and explore the nature of dissociation temperatures by employing the Quasi-Particle debye mass for pure gluonic and full QCD case. Interestingly, the dissociation temperatures obtained by employing EoS1 and EoS2 with the Γ criterion, is closer to the upper bound of the dissociation temperatures which are obtained by the dissolution of a given quarkonia state by the mean thermal energy of the quasi-partons in the hot QCD/QGP medium.

  7. Coordination and Bond Activation in Complexes of Regioisomeric Phenylpyridines with the Nickel(II) Chloride Cation in the Gas Phase

    Czech Academy of Sciences Publication Activity Database

    Tsybizova, Alexandra; Rulíšek, Lubomír; Schröder, Detlef; Rokob, Tibor András

    2013-01-01

    Roč. 117, č. 6 (2013), s. 1171-1180 ISSN 1089-5639 Grant - others:European Research Council(XE) AdG HORIZOMS Institutional support: RVO:61388963 Keywords : collision-induced dissociation * ionization mass-spectrometry * donor ligands pyridine * ion mobility measurements Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.775, year: 2013

  8. The role of the environment in the ion induced fragmentation of uracil

    Czech Academy of Sciences Publication Activity Database

    Markush, P.; Bolognesi, P.; Cartoni, A.; Rousseau, P.; Maclot, S.; Delaunay, R.; Domaracka, A.; Kočišek, Jaroslav; Castrovilli, M. C.; Huber, B. A.; Avaldi, L.

    2016-01-01

    Roč. 18, č. 25 (2016), s. 16721-16729 ISSN 1463-9076 Grant - others:COST(XE) CM1024; COST(XE) MP1002 Institutional support: RVO:61388955 Keywords : COLLISION-INDUCED DISSOCIATION * PHOTOION MASS-SPECTROMETRY * MULTIPLY-CHARGED IONS Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.123, year: 2016

  9. Dissociative Photoionization of 1-Halogenated Silacyclohexanes: Silicon Traps the Halogen.

    Science.gov (United States)

    Bodi, Andras; Sigurdardottir, Katrin Lilja; Kvaran, Ágúst; Bjornsson, Ragnar; Arnason, Ingvar

    2016-11-23

    The threshold photoelectron spectra and threshold photoionization mass spectra of 1-halogenated-1-silacyclohexanes, for the halogens X = F, Cl, Br, and I, have been obtained using synchrotron vacuum ultraviolet radiation and photoelectron photoion coincidence spectroscopy. As confirmed by a similar ionization onset and density functional theory molecular orbitals, the ionization to the ground state is dominated by electron removal from the silacyclohexane ring for X = F, Cl, and Br, and from the halogen lone pair for X = I. The breakdown diagrams show that the dissociative photoionization mechanism is also different for X = I. Whereas the parent ions decay by ethylene loss for X = F to Br in the low-energy regime, the iodine atom is lost for X = I. The first step is followed by a sequential ethylene loss at higher internal energies in each of the compounds. It is argued that the tendency of silicon to lower bond angles stabilizes the complex cation in which C 2 H 4 is η 2 -coordinated to it, and which precedes ethylene loss. Together with the relatively strong silicon-halogen bonds and the increased inductive effect of the silacyclohexane ring in stabilizing the cation, this explains the main differences observed in the fragmentation of the halogenated silacyclohexane and halogenated cyclohexane ions. The breakdown diagrams have been modeled taking into account slow dissociations at threshold and the resulting kinetic shift. The 0 K appearance energies have been obtained to within 0.08 eV for the ethylene loss for X = F to Br (10.56, 10.51, and 10.51 eV, respectively), the iodine atom loss for X = I (10.11 eV), the sequential ethylene loss for X = F to I (12.29, 12.01, 11.94, and 11.86 eV, respectively), and the minor channels of H loss for X = F (10.56 eV) and propylene loss in X = Cl (also at 10.56 eV). The appearance energies for the major channels likely correspond to the dissociative photoionization reaction energy.

  10. Data on ionization, excitation, dissociation and dissociative ionization of targets by helium ion bombardments, (1)

    International Nuclear Information System (INIS)

    Oda, Nobuo; Urakawa, Junji

    1984-03-01

    This report presents a compilation of the experimental data on cross sections for the ionization, excitation, dissociation and dissociative ionization processes of targets in helium ion impacts on atoms and molecules under a single collision condition. These measurements were carried out in the energy range from several keV to 3.5 MeV. A systematic survey has been made on the literatures from 1975 to the end of 1982. A list of references is also given, including relevant papers published before 1975. (author)

  11. Higher energy dissociative electron attachment cross sections in sulfur dioxide

    International Nuclear Information System (INIS)

    Kurepa, M.; Pejcev, V.; Cadez, I.

    2000-01-01

    Experimental results of total electron attachment cross sections are presented with, for comparison, two additional sets of data, those of Orient and Srivastava and of Spyrou et al.. Both were normalized to present values of the first attachment peak at 4,6 eV, in order to show more clearly differences in cross section curve shapes. In fact, data of Orient and Srivastava are larger that the present ones for a factor of 2,82; while those of Spyrou et al. are higher only for 3,70 %. Both these sets of data, as well as those by Cadez et al., cover an incident electron energy range 3,40 - 9,40 eV. Electron attachment processes at energies higher that 9,40 eV have been in fact detected and measured in the same set of experiments that led to former publication of lower energy attachment processes by Cadez et al.. At that time in none of experiments, that could distinguished ionic species formed in dissociation attachment processes, was a sign of ions at incident electron energies exceeding 9,40 eV. That caused our ignorance toward processes detected and measured at higher incident electron energies, mainly since they were at least one order of magnitude lower that the two peaks at 4,6 eV and 7,3 eV, respectively. Without additional experiments, that include mass analysis of ionic species formed in dissociative electron attachment processes, it is not possible to give any sound explanation to causes of peaks at energies higher that 8,0 eV

  12. The responses of dissociative patients on the thematic apperception test.

    Science.gov (United States)

    Pica, M; Beere, D; Lovinger, S; Dush, D

    2001-07-01

    This study compared the responses of dissociative inpatients and general inpatient psychiatric controls on the Thematic Apperception Test (TAT; Murray, 1943). We found the stories of dissociative participants to be characterized by a greater interpersonal distance and more trauma and dissociation responses than those of the controls. No significant differences were found regarding total number of emotional references, although references to positive emotions were almost nonexistent for the dissociative group. A post hoc analysis of the data found the testing behaviors of dissociative participants to be characterized by switching, trance states, intrainterview amnesias, and affectively loaded card rejections. Questions were raised regarding the relevancy of the findings to clinical practice and how they might explain some of the controversies surrounding the diagnosis of dissociative identity disorder (DID). Copyright 2001 John Wiley & Sons, Inc.

  13. Dissociation energy of the ground state of NaH

    International Nuclear Information System (INIS)

    Huang, Hsien-Yu; Lu, Tsai-Lien; Whang, Thou-Jen; Chang, Yung-Yung; Tsai, Chin-Chun

    2010-01-01

    The dissociation energy of the ground state of NaH was determined by analyzing the observed near dissociation rovibrational levels. These levels were reached by stimulated emission pumping and fluorescence depletion spectroscopy. A total of 114 rovibrational levels in the ranges 9≤v '' ≤21 and 1≤J '' ≤14 were assigned to the X 1 Σ + state of NaH. The highest vibrational level observed was only about 40 cm -1 from the dissociation limit in the ground state. One quasibound state, above the dissociation limit and confined by the centrifugal barrier, was observed. Determining the vibrational quantum number at dissociation v D from the highest four vibrational levels yielded the dissociation energy D e =15 815±5 cm -1 . Based on new observations and available data, a set of Dunham coefficients and the rotationless Rydberg-Klein-Rees curve were constructed. The effective potential curve and the quasibound states were discussed.

  14. Dissociative Photoionization of the Elusive Vinoxy Radical.

    Science.gov (United States)

    Adams, Jonathan D; Scrape, Preston G; Lee, Shih-Huang; Butler, Laurie J

    2017-08-24

    These experiments report the dissociative photoionization of vinoxy radicals to m/z = 15 and 29. In a crossed laser-molecular beam scattering apparatus, we induce C-Cl bond fission in 2-chloroacetaldehyde by photoexcitation at 157 nm. Our velocity measurements, combined with conservation of angular momentum, show that 21% of the C-Cl photofission events form vinoxy radicals that are stable to subsequent dissociation to CH 3 + CO or H + ketene. Photoionization of these stable vinoxy radicals, identified by their velocities, which are momentum-matched with the higher-kinetic-energy Cl atom photofragments, shows that the vinoxy radicals dissociatively photoionize to give signal at m/z = 15 and 29. We calibrated the partial photoionization cross section of vinoxy to CH 3 + relative to the bandwidth-averaged photoionization cross section of the Cl atom at 13.68 eV to put the partial photoionization cross sections on an absolute scale. The resulting bandwidth-averaged partial cross sections are 0.63 and 1.3 Mb at 10.5 and 11.44 eV, respectively. These values are consistent with the upper limit to the cross section estimated from a study by Savee et al. on the O( 3 P) + propene bimolecular reaction. We note that the uncertainty in these values is primarily dependent on the signal attributed to C-Cl primary photofission in the m/z = 35 (Cl + ) time-of-flight data. While the value is a rough estimate, the bandwidth-averaged partial photoionization cross section of vinoxy to HCO + calculated from the signal at m/z = 29 at 11.53 eV is approximately half that of vinoxy to CH 3 + . We also present critical points on the potential energy surface of the vinoxy cation calculated at the G4//B3LYP/6-311++G(3df,2p) level of theory to support the observation of dissociative ionization of vinoxy to both CH 3 + and HCO + .

  15. Lebanon and Syria: between dissociation and spillover

    Directory of Open Access Journals (Sweden)

    Javier Lion Bustillo

    2014-12-01

    Full Text Available The risk of Syrian civil war violence spreading towards Lebanon is high. This can be explained by various factors deriving as much from the neighbouring conflict as from other existing factors in Lebanese politics, which have led to the significant collaboration of Lebanon’s Future Movement and Hezbollah with their respective allies in Syria, and to undermining Najib Mikati’s dissociation policies. However, the leaders of those parties tend to balance their will to preserve their confessional leadership with an image of being the defender of national interests. This limits the possibility of an openly sectarian conflict, but it does not totally eliminate it.

  16. Dissociative Excitation of Adenine by Electron Impact

    Science.gov (United States)

    McConkey, J. William; Trocchi, Joshuah; Dech, Jeffery; Kedzierski, Wladek

    2017-04-01

    Dissociative excitation of adenine (C6H5NH2) into excited atomic fragments has been studied in the electron impact energy range from threshold to 300 eV. A crossed beam system coupled to a vacuum ultraviolet (VUV) monochromator is used to study emissions in the wavelength range from 110 to 200 nm. The beam of adenine vapor from a stainless steel oven is crossed at right angles by the electron beam and the resultant UV radiation is detected in a mutually orthogonal direction. The strongest feature in the spectrum is H Lyman- α. Financial support from NSERC and CFI, Canada, is gratefully acknowledged.

  17. Dissociation of Vertical Semiconductor Diatomic Artificial Molecules

    International Nuclear Information System (INIS)

    Pi, M.; Emperador, A.; Barranco, M.; Garcias, F.; Muraki, K.; Tarucha, S.; Austing, D. G.

    2001-01-01

    We investigate the dissociation of few-electron circular vertical semiconductor double quantum dot artificial molecules at 0T as a function of interdot distance. A slight mismatch introduced in the fabrication of the artificial molecules from nominally identical constituent quantum wells induces localization by offsetting the energy levels in the quantum dots by up to 2meV, and this plays a crucial role in the appearance of the addition energy spectra as a function of coupling strength particularly in the weak coupling limit

  18. Cognitive Processes in Dissociation: Comment on Giesbrecht et al. (2008)

    OpenAIRE

    Bremner, J. Douglas

    2010-01-01

    In “Cognitive Processes in Dissociation: An Analysis of Core Theoretical Assumptions,” published in Psychological Bulletin, Giesbrecht, Lynn, Lilienfeld, and Merckelbach (2008) have challenged the widely accepted trauma theory of dissociation, which holds that dissociative symptoms are caused by traumatic stress. In doing so the authors outline a series of links between various constructs, such as fantasy proneness, cognitive failures, absorption, suggestibility, altered information-processin...

  19. Alkali promotion of N-2 dissociation over Ru(0001)

    DEFF Research Database (Denmark)

    Mortensen, Jens Jørgen; Hammer, Bjørk; Nørskov, Jens Kehlet

    1998-01-01

    Using self-consistent density functional calculations, we show that adsorbed Na and Cs lower the barrier for dissociation of N2 on Ru(0001). Since N2 dissociation is a crucial step in the ammonia synthesis reaction, we explain in this way the experimental observation that alkali metals promote th...... the ammonia synthesis reaction over Ru catalysts. We also show that the origin of this effect is predominantly a direct electrostatic attraction between the adsorbed alkali atoms and the dissociating molecule....

  20. Numerical simulation of MH growth/dissociation by hot water injection on the Lab. experiment

    Science.gov (United States)

    Temma, N.; Sakamoto, Y.; Komai, T.; Yamaguchi, T.; Pawar, R.; Zyvoloski, G.

    2005-12-01

    Methane Hydrate (MH) is considered to be one of the new-generation energy resources. Aiming to develop the method of extraction of methane gas from MH, laboratory experiments have been performed in order to grasp the MH property in the National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba in Japan. In this paper, we present the results of the numerical simulation of experiment using by the hot water injection. In this calculation, FEHM (Finite Element Heat and Mass transfer) code is used. This code is developed at Los Alamos National Laboratory. In this experiment, temperature, pressure and cumulative gas production were measured. From these data, we suppose that MH growth/dissociation occurred by the flow of the hot water. And we make the model of the growth/dissociation. As this model consist of many parameters, it is difficult to determine parameters. Thus, we use PEST (Parameter ESTimation ) in order to determine parameters for the model of the MH growth/ dissociation. We use temperature data of experiment, as observed data. We make two observed data sets at the beginning and later term of experiment. At the results of PEST, we obtain two sets of parameters to get good match the observed data. We think that these sets indicate both the maximum and the minimum values of the MH growth/dissociation model. And, on this range, we continue to calculate until we get the good match. Finally, we obtain the numerical model of the experiment. Also, we conducted the sensitive analysis for the MH growth/ dissociation using this model.

  1. Dissociation: Defining the Concept in Criminal Forensic Psychiatry.

    Science.gov (United States)

    Bourget, Dominique; Gagné, Pierre; Wood, Stephen Floyd

    2017-06-01

    Claims of amnesia and dissociative experiences in association with a violent crime are not uncommon. Research has shown that dissociation is a risk factor for violence and is seen most often in crimes of extreme violence. The subject matter is most relevant to forensic psychiatry. Peritraumatic dissociation for instance, with or without a history of dissociative disorder, is quite frequently reported by offenders presenting for a forensic psychiatric examination. Dissociation or dissociative amnesia for serious offenses can have legal repercussions stemming from their relevance to the legal constructs of fitness to stand trial, criminal responsibility, and diminished capacity. The complexity in forensic psychiatric assessments often lies in the difficulty of connecting clinical symptomatology reported by violent offenders to a specific condition included in the Diagnostic and Statistical Manual of Mental Disorders (DSM). This article provides a review of diagnostic considerations with regard to dissociation across the DSM nomenclature, with a focus on the main clinical constructs related to dissociation. Forensic implications are discussed, along with some guides for the forensic evaluator of offenders presenting with dissociation. © 2017 American Academy of Psychiatry and the Law.

  2. Childhood maltreatment and intimate partner violence in dissociative disorder patients.

    Science.gov (United States)

    Webermann, Aliya R; Brand, Bethany L; Chasson, Gregory S

    2014-01-01

    Childhood maltreatment (CM) is a risk factor for subsequent intimate partner violence (IPV) in adulthood, with high rates of retrospectively reported CM among IPV victims and perpetrators. A theorized mechanism of the link between CM and IPV is dissociation. Dissociation may allow perpetrators of violence to remain emotionally distant from their behavior and minimize empathy toward those they victimize, enabling them to commit acts of violence similar to their own experiences. Indeed, elevated rates of dissociation and dissociative disorders (DD) have been found among IPV survivors and perpetrators. In addition, in pilot studies, DD clinicians have reported high levels of violent behavior among DD patients. The present study investigates IPV among DD patients with Dissociative Identity Disorder and Dissociative Disorder Not Otherwise Specified, a group with CM rates of 80-95% and severe dissociative symptoms. DD clinicians reported on rates of CM and IPV among 275 DD patients in outpatient treatment. DD patients also completed a self-report measure of dissociation. Analyses assessed the associations between CM typologies and IPV, as well as trait dissociation and IPV. Physical and emotional child abuse were associated with physical IPV, and childhood witnessing of domestic violence (DV) and childhood neglect were associated with emotional IPV. The present study is the first to provide empirical support for a possible CM to adult IPV developmental trajectory among DD patients. Future research is needed to better understand the link between CM and IPV among those with trauma and DD.

  3. Frontal and occipital perfusion changes in dissociative identity disorder.

    Science.gov (United States)

    Sar, Vedat; Unal, Seher N; Ozturk, Erdinc

    2007-12-15

    The aim of the study was to investigate if there were any characteristics of regional cerebral blood flow (rCBF) in dissociative identity disorder. Twenty-one drug-free patients with dissociative identity disorder and nine healthy volunteers participated in the study. In addition to a clinical evaluation, dissociative psychopathology was assessed using the Structured Clinical Interview for DSM-IV Dissociative Disorders, the Dissociative Experiences Scale and the Clinician-Administered Dissociative States Scale. A semi-structured interview for borderline personality disorder, the Hamilton Depression Rating Scale, and the Childhood Trauma Questionnaire were also administered to all patients. Normal controls had to be without a history of childhood trauma and without any depressive or dissociative disorder. Regional cerebral blood flow (rCBF) was studied with single photon emission computed tomography (SPECT) with Tc99m-hexamethylpropylenamine (HMPAO) as a tracer. Compared with findings in the control group, the rCBF ratio was decreased among patients with dissociative identity disorder in the orbitofrontal region bilaterally. It was increased in median and superior frontal regions and occipital regions bilaterally. There was no significant correlation between rCBF ratios of the regions of interest and any of the psychopathology scale scores. An explanation for the neurophysiology of dissociative psychopathology has to invoke a comprehensive model of interaction between anterior and posterior brain regions.

  4. Childhood maltreatment and intimate partner violence in dissociative disorder patients

    Directory of Open Access Journals (Sweden)

    Aliya R. Webermann

    2014-09-01

    Full Text Available Background: Childhood maltreatment (CM is a risk factor for subsequent intimate partner violence (IPV in adulthood, with high rates of retrospectively reported CM among IPV victims and perpetrators. A theorized mechanism of the link between CM and IPV is dissociation. Dissociation may allow perpetrators of violence to remain emotionally distant from their behavior and minimize empathy toward those they victimize, enabling them to commit acts of violence similar to their own experiences. Indeed, elevated rates of dissociation and dissociative disorders (DD have been found among IPV survivors and perpetrators. In addition, in pilot studies, DD clinicians have reported high levels of violent behavior among DD patients. Objective: The present study investigates IPV among DD patients with Dissociative Identity Disorder and Dissociative Disorder Not Otherwise Specified, a group with CM rates of 80–95% and severe dissociative symptoms. Methods: DD clinicians reported on rates of CM and IPV among 275 DD patients in outpatient treatment. DD patients also completed a self-report measure of dissociation. Analyses assessed the associations between CM typologies and IPV, as well as trait dissociation and IPV. Results: Physical and emotional child abuse were associated with physical IPV, and childhood witnessing of domestic violence (DV and childhood neglect were associated with emotional IPV. Conclusions: The present study is the first to provide empirical support for a possible CM to adult IPV developmental trajectory among DD patients. Future research is needed to better understand the link between CM and IPV among those with trauma and DD.

  5. Photo-dissociation of hydrogen passivated dopants in gallium arsenide

    International Nuclear Information System (INIS)

    Tong, L.; Larsson, J.A.; Nolan, M.; Murtagh, M.; Greer, J.C.; Barbe, M.; Bailly, F.; Chevallier, J.; Silvestre, F.S.; Loridant-Bernard, D.; Constant, E.; Constant, F.M.

    2002-01-01

    A theoretical and experimental study of the photo-dissociation mechanisms of hydrogen passivated n- and p-type dopants in gallium arsenide is presented. The photo-induced dissociation of the Si Ga -H complex has been observed for relatively low photon energies (3.48 eV), whereas the photo-dissociation of C As -H is not observed for photon energies up to 5.58 eV. This fundamental difference in the photo-dissociation behavior between the two dopants is explained in terms of the localized excitation energies about the Si-H and C-H bonds

  6. Dissociative features in posttraumatic stress disorder: A latent profile analysis.

    Science.gov (United States)

    Műllerová, Jana; Hansen, Maj; Contractor, Ateka A; Elhai, Jon D; Armour, Cherie

    2016-09-01

    The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) characterizes the dissociative subtype of posttraumatic stress disorder (PTSD) in terms of the individual meeting the criteria for PTSD and additionally reporting symptoms of depersonalization and/or derealization. The current study aimed to examine whether a dissociative PTSD profile may include alternative features of dissociation and whether it could be differentiated from a nondissociative PTSD profile on certain psychopathologies and demographics. Data from 309 trauma-exposed participants, collected through Amazon Mechanical Turk, were subjected to latent profile analysis. Regression analyses were used to examine the predictors of latent classes. Three discrete profiles named Baseline, PTSD, and Dissociative profile were uncovered. All examined features of dissociation were significantly elevated in the Dissociative profile. Anxiety, male sex, being employed, and having a minority racial background significantly predicted the Dissociative profile relative to the PTSD profile. The study points to the importance of alternative symptoms of dissociation in the dissociative PTSD subtype beyond the symptoms of depersonalization and derealization. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  7. Contextual Treatment of Dissociative Identity Disorder.

    Science.gov (United States)

    Gold, Steven N; Elhai, Jon D; Rea, Bayard D; Weiss, Donna; Masino, Theodore; Morris, Staci Leon; McIninch, Jessica

    2001-01-01

    Evidence for the effectiveness of contextual therapy, a new approach for treating adult survivors of prolonged child abuse (PCA), is provided via case studies of three women with Dissociative Identity Disorder (DID). Contextual therapy is based on the premise that it is not only traumatic experiences that account for PCA survivors' psychological difficulties. Even more fundamentally, many survivors grow up in an interpersonal context in which adequate resources for secure attachment and acquisition of adaptive living skills are not available. As a result, they are left with lasting deficits that undermine not only their current functioning, but also their ability to cope with reliving their traumatic memories in therapy. The primary focus of this treatment approach, therefore, is on developing capacities for feeling and functioning better in the present, rather than on extensive exploration and processing of the client's trauma history or, in the case of DID, of identity fragments. Treatment of the three cases presented ranged from eight months to two and one-half years' duration, and culminated in very positive outcomes. The women's reports of achievements, such as obtaining and maintaining gainful employment, greater self-sufficiency, and the establishment of more intimate and gratifying relationships, indicated marked improvements in daily functioning. Objective test data obtained at admission and discharge, and in one case, at follow-up, documented substantial reductions in dissociative, posttraumatic stress, depressive, and other symptoms.

  8. CO dissociation on magnetic Fen clusters

    KAUST Repository

    Jedidi, Abdesslem

    2014-01-01

    This work theoretically investigates the CO dissociation on Fen nanoparticles, for n in the range of 1-65, focusing on size dependence in the context of the initial step of the Fischer-Tropsch reaction. CO adsorbs molecularly through its C-end on a triangular facet of the nanoparticle. Dissociation becomes easier when the cluster size increases. Then, the C atom is bonded to a square facet that is generated as a result of the adsorption if it does not yet exist in the bare cluster, while the O atom is adsorbed on a triangular facet. In the most stable situation, the two adsorbed atoms remain close together, both having in common one shared first-neighbor iron atom. There is a partial spin quenching of the neighboring Fe atoms, which become more positively charged than the other Fe atoms. The shared surface iron atom resembles a metal-cation from a complex. Despite the small size of the iron cluster considered, fluctuations due to specific configurations do not influence properties for n > 25 and global trends seem significant.

  9. Autobiographical memory specificity in dissociative identity disorder.

    Science.gov (United States)

    Huntjens, Rafaële J C; Wessel, Ineke; Hermans, Dirk; van Minnen, Agnes

    2014-05-01

    A lack of adequate access to autobiographical knowledge has been related to psychopathology. More specifically, patients suffering from depression or a history of trauma have been found to be characterized by overgeneral memory, in other words, they show a relative difficulty in retrieving a specific event from memory located in time and place. Previous studies of overgeneral memory have not included patients with dissociative disorders. These patients are interesting to consider, as they are hypothesized to have the ability to selectively compartmentalize information linked to negative emotions. This study examined avoidance and overgeneral memory in patients with dissociative identity disorder (DID; n = 12). The patients completed the autobiographical memory test (AMT). Their performance was compared with control groups of posttraumatic stress disorder (PTSD) patients (n = 26), healthy controls (n = 29), and DID simulators (n = 26). Specifically, we compared the performance of separate identity states in DID hypothesized to diverge in the use of avoidance as a coping strategy to deal with negative affect. No significant differences in memory specificity were found between the separate identities in DID. Irrespective of identity state, DID patients were characterized by a lack of memory specificity, which was similar to the lack of memory specificity found in PTSD patients. The converging results for DID and PTSD patients add empirical evidence for the role of overgeneral memory involved in the maintenance of posttraumatic psychopathology.

  10. Fracture-dissociation of ceramic liner.

    Science.gov (United States)

    Hwang, Sung Kwan; Oh, Jin-Rok; Her, Man Seung; Shim, Young Jun; Cho, Tae Yeun; Kwon, Sung Min

    2008-08-01

    The use of BIOLOX delta ceramic (CeramTec AG, Plochingen, Germany) has been increasing. This ceramic prevents cracking by restraining the phase transformation due to the insertion of nano-sized, yttria-stabilized tetragonal zirconia into the alumina matrix. This restrains the progress of cracking through the formation of platelet-like crystal or whiskers due to the addition of an oxide additive. We observed a case of BIOLOX delta ceramic liner (CeramTec AG) rim fracture 4 months postoperatively. Radiographs showed that the ceramic liner was subluxated from the acetabular cup. Scratches on the acetabular cup and femoral neck were seen, and the fracture was visible on the rim of the liner. Under electron microscope, metal particle coatings from the ceramic liner were identified. The ceramic liner, fracture fragments, and adjacent tissues were removed and replaced with a ceramic liner and femoral head of the same size and design. We believe the mechanism of the fracture-dissociation of the ceramic liner in this case is similar to a case of separation of the ceramic liner from the polyethylene shell in a sandwich-type ceramic-ceramic joint. To prevent ceramic liner fracture-dissociation, the diameter of the femoral neck needs to be decreased in a new design, while the diameter of the femoral head needs to be increased to ensure an increase in range of motion.

  11. Mechanical Dissociation of Retinal Neurons with Vibration

    Science.gov (United States)

    Motomura, Tamami; Hayashida, Yuki; Murayama, Nobuki

    The neuromorphic device, which implements the functions of biological neural circuits by means of VLSI technology, has been collecting much attention in the engineering fields in the last decade. Concurrently, progress in neuroscience research has revealed the nonlinear computation in single neuron levels, suggesting that individual neurons are not merely the circuit elements but computational units. Thus, elucidating the properties of neuronal signal processing is thought to be an essential step for developing the next generation of neuromorphic devices. In the present study, we developed a method for dissociating single neurons from specific sublayers of mammalian retinas with using no proteolytic enzymes but rather combining tissue incubation in a low-Ca2+ medium and the vibro-dissociation technique developed for the slices of brains and spinal cords previously. Our method took shorter time of the procedure, and required less elaborated skill, than the conventional enzymatic method did; nevertheless it yielded enough number of the cells available for acute electrophysiological experiments. The isolated retinal neurons were useful for measuring the nonlinear membrane conductances as well as the spike firing properties under the perforated-patch whole-cell configuration. These neurons also enabled us to examine the effects of proteolytic enzymes on the membrane excitability in those cells.

  12. Dissociative identity disorder and pseudo-hysteria.

    Science.gov (United States)

    Foote, B

    1999-01-01

    The diagnostic validity of dissociative identity disorder (DID) continues to inspire controversy, with some commentators claiming that DID is a modern variant of "hysteria"; that is, attention-seeking behavior. The author asserts that DID is indeed a valid psychiatric disorder, and believes that this skeptical reaction can largely be attributed to a specific set of transference/countertransference interactions that these patients tend to inspire. The paper delineates several clinical features of DID that can easily be mistaken for hysterical phenomena, and attempts to find the roots of this confusion in the DID patients' experience of interpersonal powerlessness, which leads them to present their symptoms in an unconvincing, "hysterical" manner. Confusion between the vertical split seen in the dissociative disorders and the horizontal split characteristic of the classic hysterical personality is discussed, as is the powerful effect of observer bias in creating hysterical-appearing phenomena. The term "pseudo-hysteria" is used to denote a situation in which a genuine psychiatric disorder, DID, is perceived as an hysterical production.

  13. Dissociative Part-Dependent Resting-State Activity in Dissociative Identity Disorder: A Controlled fMRI Perfusion Study

    OpenAIRE

    Schlumpf, Yolanda R.; Reinders, Antje A. T. S.; Nijenhuis, Ellert R. S.; Luechinger, Roger; van Osch, Matthias J. P.; Jäncke, Lutz

    2014-01-01

    Background: In accordance with the Theory of Structural Dissociation of the Personality (TSDP), studies of dissociative identity disorder (DID) have documented that two prototypical dissociative subsystems of the personality, the "Emotional Part'' (EP) and the "Apparently Normal Part'' (ANP), have different biopsychosocial reactions to supraliminal and subliminal trauma-related cues and that these reactions cannot be mimicked by fantasy prone healthy controls nor by actors. Methods: Arterial ...

  14. Study of photoionization and dissociative photoionization of carbon monoxide from ionization threshold to 38 eV by using synchrotron radiation

    International Nuclear Information System (INIS)

    Zhao, Yujie; Cao, Maoqi; Li, Yuquan; Shan, Xiaobin; Liu, Fuyi; Sheng, Liusi; Li, Li; Liu, Wanfang

    2014-01-01

    Highlights: • The high resolution photoionization spectrum of carbon monoxide has been investigated using tunable synchrotron radiation. • This work has investigated comprehensively almost all kinds of photo excitation processes of CO in wide photon region. • The mechanisms of photoionization and dissociative photoionization of CO have been researched in detail. - Abstract: The vacuum-ultraviolet photoionization and dissociative photoionization of carbon monoxide in a region 14–38 eV have been investigated with time-of-flight (TOF) photoionization mass spectrometry (PIMS) using tunable synchrotron radiation (SR). The adiabatic ionization energy (IE) of carbon monoxide and appearance energies (AE) for its fragment ions in different states are determined by measurements of photoionization efficiency spectra (PIES). Ab initio calculations have been performed to investigate the reaction mechanism of dissociative photoionization of carbon monoxide. On the basis of experimental and predicted theoretical results, the mechanisms of photoionization and dissociative photoionization of molecular CO are discussed, and sixteen dissociative photoionization processes are proposed. The equilibrium geometries and harmonic vibrational frequencies of CO molecule, and its parent cation were calculated by using MP2 (full) method. The differences of configurations between them are also discussed on the basis of theoretical calculations. According to our results, the experimental IE of CO molecule, and dissociation energies (E d ) of possible dissociative channels are in reasonable agreement with the calculated values of the proposed photodissociation channels

  15. Controls on Gas Hydrate Formation and Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Miriam Kastner; Ian MacDonald

    2006-03-03

    The main objectives of the project were to monitor, characterize, and quantify in situ the rates of formation and dissociation of methane hydrates at and near the seafloor in the northern Gulf of Mexico, with a focus on the Bush Hill seafloor hydrate mound; to record the linkages between physical and chemical parameters of the deposits over the course of one year, by emphasizing the response of the hydrate mound to temperature and chemical perturbations; and to document the seafloor and water column environmental impacts of hydrate formation and dissociation. For these, monitoring the dynamics of gas hydrate formation and dissociation was required. The objectives were achieved by an integrated field and laboratory scientific study, particularly by monitoring in situ formation and dissociation of the outcropping gas hydrate mound and of the associated gas-rich sediments. In addition to monitoring with the MOSQUITOs, fluid flow rates and temperature, continuously sampling in situ pore fluids for the chemistry, and imaging the hydrate mound, pore fluids from cores, peepers and gas hydrate samples from the mound were as well sampled and analyzed for chemical and isotopic compositions. In order to determine the impact of gas hydrate dissociation and/or methane venting across the seafloor on the ocean and atmosphere, the overlying seawater was sampled and thoroughly analyzed chemically and for methane C isotope ratios. At Bush hill the pore fluid chemistry varies significantly over short distances as well as within some of the specific sites monitored for 440 days, and gas venting is primarily focused. The pore fluid chemistry in the tub-warm and mussel shell fields clearly documented active gas hydrate and authigenic carbonate formation during the monitoring period. The advecting fluid is depleted in sulfate, Ca Mg, and Sr and is rich in methane; at the main vent sites the fluid is methane supersaturated, thus bubble plumes form. The subsurface hydrology exhibits both

  16. Dipole-Guided Electron Capture Causes Abnormal Dissociations of Phosphorylated Pentapeptides

    DEFF Research Database (Denmark)

    Moss, Christopher L.; Chung, Thomas W.; Wyer, Jean

    2011-01-01

    energies and fluoranthene anion radicals in an ion trap resulted in the loss of a hydrogen atom, ammonia, and backbone cleavages forming complete series of sequence z ions. Elimination of phosphoric acid was negligible. In contrast, capture of lowenergy electrons by doubly charged ions in a Penning ion...... mapping of the potential energy surface provided structures for the precursor phosphopeptide dications. Electron attachment produces a multitude of low lying electronic states in charge-reduced ions that determine their reactivity in backbone dissociations and H- atom loss. The predominant loss of H atoms......Abstract Electron transfer and capture mass spectra of a series of doubly charged ions that were phosphorylated pentapeptides of a tryptic type (pS,A,A,A,R) showed conspicuous differences in dissociations of charge-reduced ions. Electron transfer from both gaseous cesium atoms at 100 keV kinetic...

  17. Dissociative recombination of rare gas hydride ions: II. ArH+

    International Nuclear Information System (INIS)

    Mitchell, J B A; Novotny, O; LeGarrec, J L; Florescu-Mitchell, A; Rebrion-Rowe, C; Stolyarov, A V; Child, M S; Svendsen, A; Ghazaly, M A El; Andersen, L H

    2005-01-01

    A storage ring measurement of the rate coefficient for the production of neutral Ar in e + ArH + collisions is described. It is found that the recombination rate is too small to measure at low centre-of-mass energies but the combined rate coefficient for dissociative recombination and dissociative excitation increases above 2.5 eV displaying peaks centred at 7.5 eV, 16 and 26 eV. Calculated potential energy curves for the ground and excited states of ArH + are presented and these aid in the elucidation of the recombination and excitation processes observed at higher energies. The implications for plasma modelling are discussed. (letter to the editor)

  18. Differential Fragmentation of Mobility-Selected Glycans via Ultraviolet Photodissociation and Ion Mobility-Mass Spectrometry

    Science.gov (United States)

    Morrison, Kelsey A.; Clowers, Brian H.

    2017-06-01

    The alternative dissociation pathways initiated by ultraviolet photodissociation (UVPD) compared with collision-induced dissociation (CID) may provide useful diagnostic fragments for biomolecule identification, including glycans. However, underivatized glycans do not commonly demonstrate strong UV absorbance, resulting in low fragmentation yields for UVPD spectra. In contrast to UVPD experiments that leverage covalent modification of glycans, we detail the capacity of metal adduction to yield comparatively rich UVPD fragmentation patterns and enhance separation factors for an isomeric glycan set in a drift tube ion mobility system. Ion mobility and UVPD-MS spectra for two N-acetyl glycan isomers were examined, each adducted with sodium or cobalt cations, with the latter providing fragment yield gains of an order of magnitude versus sodium adducts. Furthermore, our glycan analysis incorporated front-end ion mobility separation such that the structural glycan isomers could still be identified even as a mixture and not simply composite spectra of isomeric standards. Cobalt adduction proved influential in the glycan separation by yielding an isomer resolution of 0.78 when analyzed simultaneously versus no discernable separation obtained with the sodium adducts. It is the combined enhancement of both isomeric drift time separation and isomer distinction with improved UVPD fragment ion yields that further bolster multivalent metal adduction for advancing glycan IM-MS experiments. [Figure not available: see fulltext.

  19. Structural elucidation of AgAsS2 glass by the analysis of clusters formed during laser desorption ionisation applying quadrupole ion trap time-of-flight mass spectrometry.

    Science.gov (United States)

    Mawale, Ravi Madhukar; Alberti, Milan; Zhang, Bo; Fraenkl, Max; Wagner, Tomas; Havel, Josef

    2016-03-15

    The structure of AgA(s)S2 glass, which has a broad range of applications, is still not well understood and a systematic mass spectrometric analysis of AgA(s)S2 glass is currently not available. Elucidation of the structure should help in the development of this material. The AgA(s)S2 glass was prepared by the melt-quenched technique. Laser desorption ionisation (LDI) using quadrupole ion trap time-of-flight mass spectrometry (QIT-TOFMS) was used to follow the generation of Ag(m)As(n)S(x) clusters. The stoichiometry of the clusters generated was determined via collision-induced dissociation (CID) and modelling of isotopic patterns. The AgA(s)S2 glass was characterised by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. The LDI of AgA(s)S2 glass leads to the formation of unary (Ag+/− and As(3+)) species, 38 binary (As(n)S(x), Ag(m)S(x)), and 98 ternary (Ag(m)As(n)S(x)) singly charged clusters. The formation of silver-rich nano-grains during AgA(s)S2 glass synthesis has been identified using TEM analysis and also verified by QIT-TOFMS. TOFMS was shown to be a useful technique to study the generation of Ag(m)As(n)S(x )clusters. SEM, TEM and EDX analysis proved that the structure of AgA(s)S2 glass is ‘grain-like’ where grains are either: (1) Silver-rich ‘islands’ (Ag(m,) m up to 39) connected by arsenic and/or sulfur or arsenic sulfide chains or (2) silver sulfide (Ag2S)m (m = 9-20) clusters also similarly inter-connected. This obtained structural information may be useful for the development of ultra-high-density phase-change storage and memory devices using this kind of glass as a base.

  20. Dissociative style and individual differences in verbal working memory span.

    NARCIS (Netherlands)

    de Ruiter, M.B.; Phaf, R.H.; Elzinga, B.M.; van Dyck, R.

    2004-01-01

    Dissociative style is mostly studied as a risk factor for dissociative pathology, but it may also reflect a fundamental characteristic of healthy information processing. Due to the close link between attention and working memory and the previous finding of enhanced attentional abilities with a high

  1. Self-Destructive Behavior in People with Dissociative Disorders.

    Science.gov (United States)

    Saxe, Glenn N.; Chawla, Neharika; Van der Kolk, Bessel

    2002-01-01

    Study assesses self-destructive behavior in a group of inpatients who have dissociative disorders compared to those who report few dissociative symptoms. Results reveal that these patients more frequently engage in self-destructive behaviors, use more methods of self-injury, and begin to injure themselves at an earlier age then patients who do not…

  2. Dissociative Disorders in Children: Behavioral Profiles and Problems.

    Science.gov (United States)

    Putnam, Frank W.

    1993-01-01

    Clinical research has established a connection between childhood trauma and the development of dissociative disorders in adults. Pathological dissociation produces a range of symptoms and behaviors such as amnesias, rapid shifts in mood and behavior, and auditory and visual hallucinations. Many of these symptoms are misdiagnosed as attention,…

  3. Errors of Logic and Scholarship Concerning Dissociative Identity Disorder

    Science.gov (United States)

    Ross, Colin A.

    2009-01-01

    The author reviewed a two-part critique of dissociative identity disorder published in the "Canadian Journal of Psychiatry". The two papers contain errors of logic and scholarship. Contrary to the conclusions in the critique, dissociative identity disorder has established diagnostic reliability and concurrent validity, the trauma histories of…

  4. PTSD in relation to dissociation in traumatized police officers

    NARCIS (Netherlands)

    Carlier, I. V.; Lamberts, R. D.; Fouwels, A. J.; Gersons, B. P.

    1996-01-01

    The assumed relationship between dissociation and symptoms of posttraumatic stress disorder (PTSD) was examined. From a group of police officers who had experienced a traumatic event, the authors assessed the chronic dissociative symptoms of 42 police officers with PTSD, 50 police officers with

  5. Early Indicators of Pathological Dissociation in Sexually Abused Children.

    Science.gov (United States)

    McElroy, Linda Provus

    1992-01-01

    This paper reviews factors in the professional neglect of multiple personality disorder (MPD) and sexual abuse in childhood, as well as recent diagnostic developments in childhood dissociative disorders. The identification of subtle dissociative symptomatology in children is illustrated, and two case examples are presented. (Author)

  6. Multiple Personality and the Pathological Dissociation of Self.

    Science.gov (United States)

    Price, Reese E.

    This paper considers the condition of Multiple Personality Disorder (MPD), which is defined as a separation of alternating personalities by rigid boundaries and amnestic barriers. It is proposed that MPD represents the end of a continuum of a defensive dissociation of the self that can result when a child employs a dissociative splitting of self…

  7. The rise and fall of dissociative identity disorder.

    Science.gov (United States)

    Paris, Joel

    2012-12-01

    Dissociative identity disorder (DID), once considered rare, was frequently diagnosed during the 1980s and 1990s, after which interest declined. This is the trajectory of a medical fad. DID was based on poorly conceived theories and used potentially damaging treatment methods. The problem continues, given that the DSM-5 includes DID and accords dissociative disorders a separate chapter in its manual.

  8. Grammatical dissociation during acquired childhood aphasia.

    Science.gov (United States)

    Martins, Isabel Pavão; Loureiro, Clara; Ramos, Sara; Moreno, Teresa

    2009-12-01

    We report the case of a 6-year-old female who suffered a left hemisphere stroke attributed to a genetically determined prothrombotic state. She presented a fluent speech pattern with selective difficulty in retrieving names but not verbs. An evaluation was designed to clarify whether her symptoms represented a specific impairment of name retrieval. The child undertook an experimental battery of visual naming tasks requiring the production of 52 nouns (belonging to nine different semantic categories) and 44 verbs. Her performance was compared with that of 12 healthy children, matched for age and IQ, attending a local kindergarten. The child retrieved significantly more verbs than nouns (chi(2)=16.27, pgrammatical dissociation in a child. It suggests that nouns and verbs are subject to different processing early in development, at least before the formal acquisition of grammar. It contradicts theories that postulate a common processing of different grammatical categories early in life.

  9. Dissociative electron attachment studies on acetone

    International Nuclear Information System (INIS)

    Prabhudesai, Vaibhav S.; Tadsare, Vishvesh; Ghosh, Sanat; Gope, Krishnendu; Davis, Daly; Krishnakumar, E.

    2014-01-01

    Dissociative electron attachment (DEA) to acetone is studied in terms of the absolute cross section for various fragment channels in the electron energy range of 0–20 eV. H − is found to be the most dominant fragment followed by O − and OH − with only one resonance peak between 8 and 9 eV. The DEA dynamics is studied by measuring the angular distribution and kinetic energy distribution of fragment anions using Velocity Slice Imaging technique. The kinetic energy and angular distribution of H − and O − fragments suggest a many body break-up for the lone resonance observed. The ab initio calculations show that electron is captured in the multi-centered anti-bonding molecular orbital which would lead to a many body break-up of the resonance

  10. Dissociated dislocations in Ni: a computational study

    International Nuclear Information System (INIS)

    Szelestey, P.; Patriarca, M.; Kaski, K.

    2005-01-01

    A systematic computational study of the behavior of a (1/2) dissociated screw dislocation in fcc nickel is presented, in which atomic interactions are described through an embedded-atom potential. A suitable external stress is applied on the system, both for modifying the equilibrium separation distance d and moving the dislocation complex. The structure of the dislocation and its corresponding changes during the motion are studied in the framework of the two-dimensional Peierls model, for different values of the ratio d/a', where a' is the period of the Peierls potential. The distance between the edge and screw components of the partials, as well as their widths, undergo a modulation with period a', as the dislocation moves, and the amplitudes of such oscillations are shown to depend on d/a'. The stress profile acting on the dislocation complex is analyzed and the effective Peierls stress is estimated for different values of d/a'

  11. Multiphoton ionization/dissociation of osmium tetroxide

    International Nuclear Information System (INIS)

    Ding, D.; Puretzky, A.A.; Compton, R.N.

    1993-01-01

    The mechanisms leading to laser multiphoton ionization and dissociation (MPI/MPD) of osmium tetroxide (OsO 4 ) have been investigated from measurements of the kinetic energies of product ions (Os + , Os 2+ , OsO + , O 2 + , O + ) and photoelectrons as a function of the laser wavelength. Neutral channels, intermediate to the dominant Os + ionization channel, such as OsO 4 →OsO 4-n +nO are examined using resonance-enhanced multiphoton ionization (REMPI) of the fast O atoms. Equipartition of the available photon energy among the fragments is observed. The wavelength dependence of the Os + ion signal suggests that one or more of the steps leading to Os + ions involve molecular ions and/or excited neutral atoms. The observed preponderance of very slow ( 2+ is shown to result primarily from REMPI of Os +

  12. Dissociative electron attachment studies on acetone

    Energy Technology Data Exchange (ETDEWEB)

    Prabhudesai, Vaibhav S., E-mail: vaibhav@tifr.res.in; Tadsare, Vishvesh; Ghosh, Sanat; Gope, Krishnendu; Davis, Daly; Krishnakumar, E. [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India)

    2014-10-28

    Dissociative electron attachment (DEA) to acetone is studied in terms of the absolute cross section for various fragment channels in the electron energy range of 0–20 eV. H{sup −} is found to be the most dominant fragment followed by O{sup −} and OH{sup −} with only one resonance peak between 8 and 9 eV. The DEA dynamics is studied by measuring the angular distribution and kinetic energy distribution of fragment anions using Velocity Slice Imaging technique. The kinetic energy and angular distribution of H{sup −} and O{sup −} fragments suggest a many body break-up for the lone resonance observed. The ab initio calculations show that electron is captured in the multi-centered anti-bonding molecular orbital which would lead to a many body break-up of the resonance.

  13. Velocity slice imaging for dissociative electron attachment

    Science.gov (United States)

    Nandi, Dhananjay; Prabhudesai, Vaibhav S.; Krishnakumar, E.; Chatterjee, A.

    2005-05-01

    A velocity slice imaging method is developed for measuring the angular distribution of fragment negative ions arising from dissociative electron attachment (DEA) to molecules. A low energy pulsed electron gun, a pulsed field ion extraction, and a two-dimensional position sensitive detector consisting of microchannel plates and a wedge-and-strip anode are used for this purpose. Detection and storage of each ion separately for its position and flight time allows analysis of the data offline for any given time slice, without resorting to pulsing the detector bias. The performance of the system is evaluated by measuring the angular distribution of O- from O2 and comparing it with existing data obtained using conventional technique. The capability of this technique in obtaining forward and backward angular distribution data is shown to have helped in resolving one of the existing problems in the electron scattering on O2.

  14. Diffraction dissociation: thirty five years after

    International Nuclear Information System (INIS)

    Zotov, N.P.; Tsarev, V.A.

    1988-01-01

    Review of the basic results and stages of studying one of the most interesting phenomena in high energy physics-diffraction dissociation (DD) of hadrons is presented. The review contains complete information concerning the basic experimental results and the most ''set'' DD theoretical models. Though the discussion focuses primarily on considering a single nucleon DD, this still allows one to fully describe the basic features of the phenomenon under investigation. The last part of the review is devoted to the most notable results obtained during DD experimental investigation in the last five years, which have not been reflected in the earlier published reviews. Signs of excited system parton structure and pomeron are clearly found in the new experimental data. It is underlined that DD mechanism understanding is closely connected with the solution of the confinement problem in the strong interaction theory and requires further experimental and theoretical investigations

  15. Thermal dissociation and unfolding of insulin

    DEFF Research Database (Denmark)

    Huus, Kasper; Havelund, Svend; Olsen, Helle B

    2005-01-01

    The thermal stability of human insulin was studied by differential scanning microcalorimetry and near-UV circular dichroism as a function of zinc/protein ratio, to elucidate the dissociation and unfolding processes of insulin in different association states. Zinc-free insulin, which is primarily...... dimeric at room temperature, unfolded at approximately 70 degrees C. The two monomeric insulin mutants Asp(B28) and Asp(B9),Glu(B27) unfolded at higher temperatures, but with enthalpies of unfolding that were approximately 30% smaller. Small amounts of zinc caused a biphasic thermal denaturation pattern...... of insulin. The biphasic denaturation is caused by a redistribution of zinc ions during the heating process and results in two distinct transitions with T(m)'s of approximately 70 and approximately 87 degrees C corresponding to monomer/dimer and hexamer, respectively. At high zinc concentrations (>or=5 Zn(2...

  16. Regularity and mass conservation for discrete coagulation–fragmentation equations with diffusion

    KAUST Repository

    Cañizo, J.A.

    2010-03-01

    We present a new a priori estimate for discrete coagulation-fragmentation systems with size-dependent diffusion within a bounded, regular domain confined by homogeneous Neumann boundary conditions. Following from a duality argument, this a priori estimate provides a global L2 bound on the mass density and was previously used, for instance, in the context of reaction-diffusion equations. In this paper we demonstrate two lines of applications for such an estimate: On the one hand, it enables to simplify parts of the known existence theory and allows to show existence of solutions for generalised models involving collision-induced, quadratic fragmentation terms for which the previous existence theory seems difficult to apply. On the other hand and most prominently, it proves mass conservation (and thus the absence of gelation) for almost all the coagulation coefficients for which mass conservation is known to hold true in the space homogeneous case. © 2009 Elsevier Masson SAS. All rights reserved.

  17. Site selective dissociation of ozone upon core excitation

    International Nuclear Information System (INIS)

    Mocellin, A.; Mundim, M.S.P.; Coutinho, L.H.; Homem, M.G.P.; Naves de Brito, A.

    2007-01-01

    We present new measurements applied to core excitation of ozone molecule using to analyze the dissociation channels the photo-electron-photo-ion coincidence (PEPICO) and the photo-electron-photo-ion-photo-ion coincidence (PEPIPICO) technique. The new experimental set-up allows measuring O + /O + ion pair coincidences without discrimination. The dissociation channels of several core-excited states have been investigated. The relative yields of dissociation channels were determined from coincidence data. The core excitation from O terminal (O T ) or O central (O C ) induce different fragmentation; preferentially one bond is broken at the O terminal excitation and two bonds when O central is excited, showing site selectivity fragmentation of ozone upon core excitation. The ultra-fast dissociation of the O T 1s -1 7a 1 1 core-excited state is confirmed by the relative yield of dissociation

  18. Site selective dissociation of ozone upon core excitation

    Energy Technology Data Exchange (ETDEWEB)

    Mocellin, A. [Instituto de Fisica, Universidade de Brasilia-UnB, Box 04455, CEP 70919-970, Brasilia-DF (Brazil)], E-mail: mocellin@fis.unb.br; Mundim, M.S.P. [Instituto de Fisica, Universidade de Brasilia-UnB, Box 04455, CEP 70919-970, Brasilia-DF (Brazil); Coutinho, L.H. [Instituto de Quimica, Universidade Federal do Rio de Janeiro-UFRJ, Box 68563, CEP 21945-970, Rio de Janeiro-RJ (Brazil); Homem, M.G.P. [Laboratorio Nacional de Luz Sincrotron-LNLS, Box 6192, CEP 13084-971, Campinas-SP (Brazil); Naves de Brito, A. [Laboratorio Nacional de Luz Sincrotron-LNLS, Box 6192, CEP 13084-971, Campinas-SP (Brazil); Instituto de Fisica, Universidade de Brasilia-UnB, Box 04455, CEP 70919-970, Brasilia-DF (Brazil)

    2007-05-15

    We present new measurements applied to core excitation of ozone molecule using to analyze the dissociation channels the photo-electron-photo-ion coincidence (PEPICO) and the photo-electron-photo-ion-photo-ion coincidence (PEPIPICO) technique. The new experimental set-up allows measuring O{sup +}/O{sup +} ion pair coincidences without discrimination. The dissociation channels of several core-excited states have been investigated. The relative yields of dissociation channels were determined from coincidence data. The core excitation from O terminal (O{sub T}) or O central (O{sub C}) induce different fragmentation; preferentially one bond is broken at the O terminal excitation and two bonds when O central is excited, showing site selectivity fragmentation of ozone upon core excitation. The ultra-fast dissociation of the O{sub T} 1s{sup -1}7a{sub 1}{sup 1} core-excited state is confirmed by the relative yield of dissociation.

  19. Unresolved mourning, supernatural beliefs and dissociation: a mediation analysis.

    Science.gov (United States)

    Thomson, Paula; Jaque, S Victoria

    2014-01-01

    Unresolved mourning is marked by disorganized behavior and states of mind. In this study, we speculated that pathological dissociation would mediate the effects of unresolved mourning on supernatural beliefs. This hypothesis was determined based on findings that indicate an association between higher levels of dissociation, stronger beliefs in the supernatural and unresolved mourning. We examined two groups of participants, one classified as non-unresolved (non-U) (n = 56) and the other as unresolved (n = 26) (U) with respect to past loss/trauma as measured by the Adult Attachment Interview (AAI). Two self-report instruments were administered to measure supernatural beliefs and dissociation. As hypothesized, the multivariate analysis of variance indicated mean differences between the two groups. The unresolved group had greater belief in the supernatural and more pathological dissociative processes. The mediation analysis demonstrated that pathological dissociation fully mediated the effects of unresolved mourning on supernatural beliefs.

  20. Dissociation behavior of methane gas hydrate in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, C.; Yu-gang, Y.; Chang-ling, L. [Ministry of Land and Resources, Quindao (China). Qingdao Inst. of Marine Geology; Qing-guo, M. [Qingdao Univ. College of Chemical Engineering and Environment, Shandong, Qingdao (China)

    2008-07-01

    Gas hydrates are ice-like compounds that form by natural gas and water and are considered to be a new energy resource. In order to make good use of this resource, it is important to know the hydrate dissociation process. This paper discussed an investigation of methane hydrate dissociation through a simulation experiment. The paper discussed the gas hydrates dissociation experiment including the apparatus and experiment equipment, including methane gas supply; reaction cell; temperature controller; pressure maintainer; and gas flow meter. The paper also presented the method and material including iso-volumetric dissociation and normal pressure dissociation. Last, results and discussion of the results were presented. A comparison of five different particle sizes did not reveal any obvious effects that were related to the porous media, mostly likely because the particle size was too large. 15 refs., 2 tabs., 4 figs.

  1. Dissociative identity disorder: An empirical overview.

    Science.gov (United States)

    Dorahy, Martin J; Brand, Bethany L; Sar, Vedat; Krüger, Christa; Stavropoulos, Pam; Martínez-Taboas, Alfonso; Lewis-Fernández, Roberto; Middleton, Warwick

    2014-05-01

    Despite its long and auspicious place in the history of psychiatry, dissociative identity disorder (DID) has been associated with controversy. This paper aims to examine the empirical data related to DID and outline the contextual challenges to its scientific investigation. The overview is limited to DID-specific research in which one or more of the following conditions are met: (i) a sample of participants with DID was systematically investigated, (ii) psychometrically-sound measures were utilised, (iii) comparisons were made with other samples, (iv) DID was differentiated from other disorders, including other dissociative disorders, (v) extraneous variables were controlled or (vi) DID diagnosis was confirmed. Following an examination of challenges to research, data are organised around the validity and phenomenology of DID, its aetiology and epidemiology, the neurobiological and cognitive correlates of the disorder, and finally its treatment. DID was found to be a complex yet valid disorder across a range of markers. It can be accurately discriminated from other disorders, especially when structured diagnostic interviews assess identity alterations and amnesia. DID is aetiologically associated with a complex combination of developmental and cultural factors, including severe childhood relational trauma. The prevalence of DID appears highest in emergency psychiatric settings and affects approximately 1% of the general population. Psychobiological studies are beginning to identify clear correlates of DID associated with diverse brain areas and cognitive functions. They are also providing an understanding of the potential metacognitive origins of amnesia. Phase-oriented empirically-guided treatments are emerging for DID. The empirical literature on DID is accumulating, although some areas remain under-investigated. Existing data show DID as a complex, valid and not uncommon disorder, associated with developmental and cultural variables, that is amenable to

  2. Attention as a characteristic of nonclinical dissociation: an event-related potential study

    NARCIS (Netherlands)

    de Ruiter, Michiel B.; Phaf, R. Hans; Veltman, Dick J.; Kok, Albert; van Dyck, Richard

    2003-01-01

    Individual differences in dissociative style (which is generally considered a risk factor for dissociative pathology) were studied in a nonclinical sample. It was hypothesized that high-dissociative participants would show enhanced attentional abilities toward both relevant and irrelevant stimulus

  3. Parents' descriptions of young children's dissociative reactions after trauma.

    Science.gov (United States)

    Cintron, Gabriela; Salloum, Alison; Blair-Andrews, Zoe; Storch, Eric A

    2017-10-09

    There is limited research on the phenomenology of how young children who have been exposed to trauma express the intrusive symptom of dissociative reactions. The current qualitative study utilized interviews from a semi-structured diagnostic clinical interview with 74 caregivers of young children (ages 3 to 7) who were exposed to trauma to identify parents' descriptions of their children's dissociative reactions during a clinical interview. Based on results from the interview, 45.9% of the children had dissociative reactions (8.5% had flashbacks and 41.9% had dissociative episodes). Interviews were transcribed to identify themes of dissociative reactions in young children. Common themes to flashbacks and dissociative episodes included being triggered, being psychologically in their own world (e.g., spaced out and shut down), and displaying visible signs (e.g., crying and screaming). For flashbacks, caregivers reported that it seemed as if the child was re-experiencing the trauma (e.g., yelling specific words and having body responses). For dissociative episodes, caregivers noted that the child not only seemed psychologically somewhere else (e.g., distant and not there) but also would be physically positioned somewhere else (e.g., sitting and not responding). Caregivers also expressed their own reactions to the child's dissociative episode due to not understanding what was occurring, and trying to interrupt the occurrences (e.g., calling out to the child). Themes, descriptions, and phrases to describe dissociative reactions in young children after trauma can be used to help parents and professionals more accurately identify occurrences of dissociative reactions.

  4. Ionisation and dissociation of water induced by swift multicharged ions

    International Nuclear Information System (INIS)

    Legendre, S.

    2006-02-01

    Ionization and dissociation of water molecules and water clusters induced by 11.7 MeV/A Ni 25+ ions were carried out by imaging techniques. Branching ratios, ionisation cross sections and Kinetic Energy Released distributions have been measured together with fragmentation dynamics studies. Multiple ionization represents approximately 30% of the ionizing events. Double ionization produces in significant way atomic oxygen, considered as a possible precursor of the large production of HO 2 radical in liquid water radiolysis by ions of high Linear Energy Transfer. We evidence a strong selectivity of bond breakage in the case of ion-induced HOD fragmentation. Once the molecule doubly ionized, the breakage of the O-H bond is found 6.5 times more probable than that of the O-D bond. A semi-classical calculation simulating the fragmentation dynamics on the potential energy surface of the ground-state of di-cation H 2 O 2+ makes possible to as well reproduce the preferential nature of the breakage of the O-H bond as the position and the shift of the kinetic energy distributions. First results concerning interaction with water clusters are also reported. Measurements in coincidence are carried out giving access to correlation, with the distributions in energy and angle of the emitted fragments. Mass spectrum points fast intra-cluster proton transfer, leading to the emission of protonated clusters. (author)

  5. Infrared Multiple Photon Dissociation Spectroscopy Of Metal Cluster-Adducts

    Science.gov (United States)

    Cox, D. M.; Kaldor, A.; Zakin, M. R.

    1987-01-01

    Recent development of the laser vaporization technique combined with mass-selective detection has made possible new studies of the fundamental chemical and physical properties of unsupported transition metal clusters as a function of the number of constituent atoms. A variety of experimental techniques have been developed in our laboratory to measure ionization threshold energies, magnetic moments, and gas phase reactivity of clusters. However, studies have so far been unable to determine the cluster structure or the chemical state of chemisorbed species on gas phase clusters. The application of infrared multiple photon dissociation IRMPD to obtain the IR absorption properties of metal cluster-adsorbate species in a molecular beam is described here. Specifically using a high power, pulsed CO2 laser as the infrared source, the IRMPD spectrum for methanol chemisorbed on small iron clusters is measured as a function of the number of both iron atoms and methanols in the complex for different methanol isotopes. Both the feasibility and potential utility of IRMPD for characterizing metal cluster-adsorbate interactions are demonstrated. The method is generally applicable to any cluster or cluster-adsorbate system dependent only upon the availability of appropriate high power infrared sources.

  6. Testing the diagnosis of dissociative identity disorder through measures of dissociation, absorption, hypnotizability and PTSD: a Norwegian pilot study.

    Science.gov (United States)

    Dale, Karl Yngvar; Berg, Renate; Elden, Ake; Ødegård, Atle; Holte, Arne

    2009-01-01

    A total of 14 women meeting criteria for dissociative identity disorder (DID) based on the Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV]) were compared to a group of women (n = 10) with other dissociative diagnoses and a group of normal controls (n = 14) with regard to dissociativity, absorption, trauma related symptoms and hypnotizability. Both of the clinical groups reported histories of childhood trauma and attained high PTSD scores. The DID group differed significantly from the group with other dissociative diagnoses and the non-diagnosed comparison group with regard to hypnotizability, the variety of dissociative symptomatology, and the magnitude of dissociative symptomatology. However, no significant differences between the two clinical groups were detected with regard to absorption, general dissociative level, or symptoms related to traumatic stress. Results support the notion that DID can be regarded as a clinical entity which is separable from other dissociative disorders. Results also indicated that hypnotizability is the most important clinical feature of DID.

  7. Dissociative, depressive, and PTSD symptom severity as correlates of nonsuicidal self-injury and suicidality in dissociative disorder patients.

    Science.gov (United States)

    Webermann, Aliya R; Myrick, Amie C; Taylor, Christina L; Chasson, Gregory S; Brand, Bethany L

    2016-01-01

    The present study investigates whether symptom severity can distinguish patients diagnosed with dissociative identity disorder and dissociative disorder not otherwise specified with a recent history of nonsuicidal self-injury (NSSI) and suicide attempts from those patients without recent self-harm. A total of 241 clinicians reported on recent history of patient NSSI and suicide attempts. Of these clinicians' patients, 221 completed dissociative, depressive, and posttraumatic stress disorder symptomatology measures. Baseline cross-sectional data from a naturalistic and prospective study of dissociative disorder patients receiving community treatment were utilized. Analyses evaluated dissociative, depressive, and posttraumatic stress disorder symptom severity as methods of classifying patients into NSSI and suicide attempt groupings. Results indicated that dissociation severity accurately classified patients into NSSI and suicidality groups, whereas depression severity accurately classified patients into NSSI groups. These findings point to dissociation and depression severity as important correlates of NSSI and suicidality in patients with dissociative disorders and have implications for self-harm prevention and treatment.

  8. Photoleucine Survives Backbone Cleavage by Electron Transfer Dissociation. A Near-UV Photodissociation and Infrared Multiphoton Dissociation Action Spectroscopy Study

    Czech Academy of Sciences Publication Activity Database

    Shaffer, C. J.; Martens, J.; Marek, Aleš; Oomens, J.; Tureček, F.

    2016-01-01

    Roč. 27, č. 7 (2016), s. 1176-1185 ISSN 1044-0305 Institutional support: RVO:61388963 Keywords : peptide ions * electron transfer dissociation * photoleucine label * near-UV photodissociation * infrared multiphoton dissociation action spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.786, year: 2016

  9. Abnormal Hippocampal Morphology in Dissociative Identity Disorder and Post-Traumatic Stress Disorder Correlates with Childhood Trauma and Dissociative Symptoms

    NARCIS (Netherlands)

    Chalavi, Sima; Vissia, Eline M.; Giesen, Mechteld E.; Nijenhuis, Ellert R. S.; Draijer, Nel; Cole, James H.; Dazzan, Paola; Pariante, Carmine M.; Madsen, Sarah K.; Rajagopalan, Priya; Thompson, Paul M.; Toga, Arthur W.; Veltman, Dick J.; Reinders, Antje A. T. S.

    Smaller hippocampal volume has been reported in individuals with post-traumatic stress disorder (PTSD) and dissociative identity disorder (DID), but the regional specificity of hippocampal volume reductions and the association with severity of dissociative symptoms and/or childhood traumatization

  10. Abnormal Hippocampal Morphology in Dissociative Identity Disorder and Post-Traumatic Stress Disorder Correlates with Childhood Trauma and Dissociative Symptoms

    NARCIS (Netherlands)

    Chalavi, S.; Vissia, E.M.; Giesen, M.E.; Nijenhuis, E.R.S.; Draijer, N.; Cole, J.H.; Dazzan, P.; Pariante, C.M.; Madsen, S.K.; Rajagopalan, P.; Thompson, P.M.; Toga, A.W.; Veltman, D.J.; Reinders, A.A.T.S

    2015-01-01

    Smaller hippocampal volume has been reported in individuals with post-traumatic stress disorder (PTSD) and dissociative identity disorder (DID), but the regional specificity of hippocampal volume reductions and the association with severity of dissociative symptoms and/or childhood traumatization

  11. Multiphoton ionization as a probe of molecular photofragmentation: statistical and dynamical energy partitioning in the multiphoton dissociation of nitromethane

    International Nuclear Information System (INIS)

    Rockney, B.H.

    1982-01-01

    Multiphoton ionization (MPI) appears in its first use as a probe of laser-induced photofragmentation. Specifically, MPI here reveals the internal and translational energy content of the nascent fragments from the infrared multiphoton dissociation (MPD) of nitromethane (CH 3 NO 2 ). The apparatus for this work consists of a pulsed supersonic molecular beam crossed by two pulsed and focused lasers - a CO 2 laser to induce collision-free unimolecular dissociation of CH 3 NO 2 , and a tunable dye laser following immediately to ionize selectively one of the pair of dissociation fragments for detection by a mass spectrometer and particle multiplier. A computer simulation of each fragment's MPI spectrum, a series of four photon resonances to members of the npsigma/sub u/ Rydberg state of NO 2 and three photon resonances to two vibrational members of the #betta# 1 Rydberg state of CH 3 , aids in determining the fragment's internal energy content. The dye laser is delayed and its focus is traced through a small quarter circle centered at the focus of the CO 2 laser. The flight times of the fragments from the point of dissociation and their laboratory scattering angular distributions at fixed ionizing laser wavelength provide their center of mass recoil velocity distributions. The energy deposited in the fragments evidences a striking mixture of statistical and dynamical energy partitioning. The statistical RRKM theory of unimolecular decomposition accurately predicts the amount of internal energy found in the fragments

  12. Dissociative electron attachment to the gas-phase nucleobase hypoxanthine

    Energy Technology Data Exchange (ETDEWEB)

    Dawley, M. Michele [Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Tanzer, Katrin; Denifl, Stephan, E-mail: Stephan.Denifl@uibk.ac.at, E-mail: Sylwia.Ptasinska.1@nd.edu [Institut für Ionenphysik und Angewandte Physik, and Center for Molecular Biosciences Innsbruck (CMBI), Leopold-Franzens Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck (Austria); Carmichael, Ian [Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Ptasińska, Sylwia, E-mail: Stephan.Denifl@uibk.ac.at, E-mail: Sylwia.Ptasinska.1@nd.edu [Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

    2015-06-07

    We present high-resolution measurements of the dissociative electron attachment (DEA) to isolated gas-phase hypoxanthine (C{sub 5}H{sub 4}N{sub 4}O, Hyp), a tRNA purine base. The anion mass spectra and individual ion efficiency curves from Hyp were measured as a function of electron energy below 9 eV. The mass spectra at 1 and 6 eV exhibit the highest anion yields, indicating possible common precursor ions that decay into the detectable anionic fragments. The (Hyp − H) anion (C{sub 5}H{sub 3}N{sub 4}O{sup −}) exhibits a sharp resonant peak at 1 eV, which we tentatively assign to a dipole-bound state of the keto-N1H,N9H tautomer in which dehydrogenation occurs at either the N1 or N9 position based upon our quantum chemical computations (B3LYP/6-311+G(d,p) and U(MP2-aug-cc-pVDZ+)) and prior studies with adenine. This closed-shell dehydrogenated anion is the dominant fragment formed upon electron attachment, as with other nucleobases. Seven other anions were also observed including (Hyp − NH){sup −}, C{sub 4}H{sub 3}N{sub 4}{sup −}/C{sub 4}HN{sub 3}O{sup −}, C{sub 4}H{sub 2}N{sub 3}{sup −}, C{sub 3}NO{sup −}/HC(HCN)CN{sup −}, OCN{sup −}, CN{sup −}, and O{sup −}. Most of these anions exhibit broad but weak resonances between 4 and 8 eV similar to many analogous anions from adenine. The DEA to Hyp involves significant fragmentation, which is relevant to understanding radiation damage of biomolecules.

  13. A combination thermal dissociation/electron impact ionization source for RIB generation

    International Nuclear Information System (INIS)

    Alton, G.D.; Cui, B.; Welton, R.F.

    1996-01-01

    The flourishing interest in radioactive ion beams (RIBs) with intensities adequate for astrophysics and nuclear physics research place a premium on targets that will swiftly release trace amounts of short lived radio-nuclei in the presence of bulk quantities of target material and ion sources that have the capability of efficiently ionizing the release products. Because of the low probability of simultaneously dissociating and efficiently ionizing the individual atomic constituents of molecules containing the element of interest with conventional, hot-cathode, electron-impact ion sources, the species of interest is often distributed in several mass channels in the form of molecular sideband beams and, consequently, the intensity is diluted. The authors have conceived an ion source that combines the excellent molecular dissociation properties of a thermal dissociator and the high efficiency characteristics of an electron impact ionization source to address these problems. If the concept proves to be a viable option, the source will be used as a complement to the electron beam plasma ion sources already in use at the HRIBF. The design features and principles of operation of the source are described in this article

  14. Dissociative disorders in acute psychiatric inpatients in Taiwan.

    Science.gov (United States)

    Chiu, Chui-De; Meg Tseng, Mei-Chih; Chien, Yi-Ling; Liao, Shih-Cheng; Liu, Chih-Min; Yeh, Yei-Yu; Hwu, Hai-Gwo; Ross, Colin A

    2017-04-01

    Dissociative disorders have been documented to be common psychiatric disorders which can be detected reliably with standardized diagnostic instruments in North American and European psychiatric inpatients and outpatients (20.6% and 18.4%, respectively). However, there are concerns about their cross-cultural manifestations as an apparently low prevalence rate has been reported in East Asian inpatients and outpatients (1.7% and 4.9%, respectively). It is unknown whether the clinical profile of dissociative disorders in terms of their core symptomatic clusters, associated comorbid disorders, and environmental risk factors that has emerged in western clinical populations can also be found in non-western clinical populations. A standardized structured interview for DSM-IV dissociative disorders, post-traumatic stress disorder, and a history of interpersonal victimization was administered in a sample of Taiwanese acute psychiatric inpatients. Our results showed that 19.5% of our participants met criteria for a DSM-IV dissociative disorder, mostly dissociative disorder not otherwise specified. More importantly, the western clinical profile of dissociative disorders also characterized our patients, including a poly-symptomatic presentation and a history of interpersonal trauma in both childhood and adulthood. Our results lend support to the conclusion that cross-cultural manifestations of dissociative pathology in East Asia are similar to those in North America and Europe. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  15. Trauma-Related Dissociation Is Linked With Maladaptive Personality Functioning

    Directory of Open Access Journals (Sweden)

    Antonella Granieri

    2018-05-01

    Full Text Available Background: Extensive research has demonstrated the positive associations among the exposure to traumatic experiences, the levels of dissociation, and the severity of psychiatric symptoms in adults. However, it has been hypothesized in clinical literature that an excessive activation of the dissociative processes following multiple traumatic experiences may jeopardize the psychological and behavioral functioning of the individuals, fostering higher levels of maladaptive personality functioning.Methods: The study involved 322 adult volunteers from Italy. Participants completed measures on traumatic experiences, dissociation, and maladaptive personality traits.Results: The number of traumatic experiences reported by participants were positively associated with dissociation scores and maladaptive personality scores. Mediation analyses showed that dissociation acted as a partial mediator in the relationship between traumatic experiences and overall maladaptive personality functioning. Regression curve analyses showed that the positive association between maladaptive personality functioning and dissociation was stronger among participants with higher exposure to traumatic experiences.Conclusion: Exposure to multiple traumatic experiences may increase the risk for an excessive activation of the dissociative processes, which in turn may generate severe impairments in multiple domains of personality functioning.

  16. High psychiatric comorbidity in adolescents with dissociative disorders.

    Science.gov (United States)

    Bozkurt, Hasan; Duzman Mutluer, Tuba; Kose, Cigdem; Zoroglu, Salih

    2015-06-01

    The aim of this study was to evaluate psychiatric comorbidity rates and patterns in a sample of clinically referred adolescents diagnosed with dissociative disorders (DD) by using a structured interview. All participants completed a comprehensive test battery, which consisted of a questionnaire for sociodemographic data and clinical history, Child Posttraumatic Stress Reaction Index, Childhood Abuse and Neglect Questionnaire and the Adolescent Dissociative Experiences Scale. Diagnosis was made by the Structured Clinical Interview for DSM-IV Dissociative Disorders. Psychiatric comorbidity was assessed using the Schedule for Affective Disorders and Schizophrenia for School Age Children - Present and Lifetime Version. A total of 25 adolescent subjects aged 12-18 years participated in the study. Ten adolescents were diagnosed as having dissociative identity disorder and 15 of them were diagnosed as having dissociative disorder-not otherwise specified based on the Structured Clinical Interview for DSM-IV Dissociative Disorders findings. Adolescents with dissociative identity disorder were found to have higher scores on the Adolescent Dissociative Experiences Scale and Child Posttraumatic Stress Reaction Index than the dissociative disorder-not otherwise specified group. Sexual and physical abuses were also found to be among the main traumatic events. Incest was reported in six cases of the study sample. All subjects had at least one comorbid psychiatric disorder. The most common psychiatric diagnoses were major depressive disorder (n = 25; 100%) and post-traumatic stress disorder (n = 22; 88%). High psychiatric comorbidity rates were found in adolescents diagnosed with DD. A prevalent history of abuse and traumatic events was represented. Clinicians should be aware of the impacts of DD on adolescents' mental health. © 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.

  17. Dynamics of dissociative adsorption of hydrogen on Ni(100)

    International Nuclear Information System (INIS)

    Hamza, A.V.; Madix, R.J.

    1985-01-01

    Nearly monoenergetic beams of hydrogen and deuterium were used to determine dissociative sticking probabilities for H 2 and D 2 on Ni(100) at various energies. Variation of the surface temperature between 90 and 300 K had no effect on the dissociative sticking probability of H 2 at 3.6 and 5.8 kJ/mol incident beam energy, indicating a direct mechanism of dissociation. A four fold increase in the initial dissociative sticking probability for H 2 from 0.2 to 0.8 was observed by increasing the translational kinetic energy from 0.7 to 7.0 kJ/mol. The initial dissociative sticking probability for D 2 was slightly lower, increasing from 0.15 to 0.75 with increasing translational kinetic energy from 1.3 to 10.5 kJ/mol. The form of the increase with kinetic energy was explained by tunnelling through a low activation barrier, accounting as well for the high dissociation probability at low kinetic energies. The dissociative sticking probability decreased with hydrogen or deuterium adatom coverage at all energies. The decline in sticking probability with hydrogen coverage was fit to a s(theta) = s 0 (1 - a theta)/sup n/ functional form. From this relationship it was deduced that hydrogen adatoms block only single sites and that four vacant sites are needed for dissociation. The dissociative sticking probability for H 2 declined precipitously from 0.77 to 0.16 with oxygen adatom coverage from 0 to 5% of a monolayer at a translational energy of 9.6 kJ.mol. 36 references, 8 figures

  18. INTRAMOLECULAR ISOTOPE EFFECTS IN HYDROCARBON MASS SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, D. P.; Schachtschneider, J. H.

    1963-07-15

    Approximate calculations based on the quasi-equilibrium rate theory of the origin of mass spectra are shown to lead to an approximately correct magnitude for the intramolecular ( pi /sup -/) isotope effect on C--H bond dissociation probabilities of various deuterohydrocarbons. (auth)

  19. Dissociative photoionization of 1,3-butadiene: experimental and theoretical insights.

    Science.gov (United States)

    Fang, Wenzheng; Gong, Lei; Zhang, Qiang; Shan, Xiaobin; Liu, Fuyi; Wang, Zhenya; Sheng, Liusi

    2011-05-07

    The vacuum-ultraviolet photoionization and dissociative photoionization of 1,3-butadiene in a region ∼8.5-17 eV have been investigated with time-of-flight photoionization mass spectrometry using tunable synchrotron radiation. The adiabatic ionization energy of 1,3-butadiene and appearance energies for its fragment ions, C(4)H(5)(+), C(4)H(4)(+), C(4)H(3)(+), C(3)H(3)(+), C(2)H(4)(+), C(2)H(3)(+), and C(2)H(2)(+), are determined to be 9.09, 11.72, 13.11, 15.20, 11.50, 12.44, 15.15, and 15.14 eV, respectively, by measurements of photoionization efficiency spectra. Ab initio molecular orbital calculations have been performed to investigate the reaction mechanism of dissociative photoionization of 1,3-butadiene. On the basis of experimental and theoretical results, seven dissociative photoionization channels are proposed: C(4)H(5)(+) + H, C(4)H(4)(+) + H(2), C(4)H(3)(+) + H(2) + H, C(3)H(3)(+) + CH(3), C(2)H(4)(+) + C(2)H(2), C(2)H(3)(+) + C(2)H(2) + H, and C(2)H(2)(+) + C(2)H(2) + H(2). Channel C(3)H(3)(+) + CH(3) is found to be the dominant one, followed by C(4)H(5)(+) + H and C(2)H(4)(+) + C(2)H(2). The majority of these channels occur via isomerization prior to dissociation. Transition structures and intermediates for those isomerization processes were also determined.

  20. Furfural: The Unimolecular Dissociative Photoionization Mechanism of the Simplest Furanic Aldehyde.

    Science.gov (United States)

    Winfough, Matthew; Voronova, Krisztina; Muller, Giel; Laguisma, Gabrielle; Sztáray, Bálint; Bodi, Andras; Meloni, Giovanni

    2017-05-11

    The unimolecular dissociation reactions of energy-selected furfural cations have been studied by imaging photoelectron photoion coincidence spectroscopy at the vacuum-ultraviolet (VUV) beamline of the Swiss Light Source. In the photon energy range of 10.9-14.5 eV, furfural ions decay by numerous fragmentation channels. Modeling the breakdown diagram yielded the 0 K appearance energies of 10.95 ± 0.10, 11.16, and 12.03 eV for the c-C 4 H 3 O-CO + (m/z = 95), c-C 4 H 4 O + (m/z = 68), and c-C 3 H 3 + (m/z = 39) fragment ions, respectively, formed by parallel dissociation channels. An internal conversion from the A″ to the A' electronic state via a conical intersection takes place along the reaction coordinate in the case of the H-loss channel (c-C 4 H 3 O-CO + formation). Quantum chemical calculations and experimental results confirmed a fast conversion to the A' state and that the rate-determining step is a tight transition state on the potential energy surface. Appearance energies were also derived for the sequential dissociation products from the furan cation, c-C 4 H 4 O + , for the formation of CH 2 CO + (m/z = 42), C 3 H 4 + (m/z = 40), and CHO + (m/z = 29) at 12.81, 12.80, and 13.34 eV, respectively. Statistical rate theory modeling of the breakdown diagram can also be used to predict the fractional ion abundances and thermal shifts in mass spectrometric pyrolysis studies to help assigning the m/z channels either to ionization of the neutrals or to dissociative ionization processes, with potential use for combustion diagnostics. The cationic geometry optimizations yielded functional-dependent spurious DFT minima and a deviating planar MP2 optimized geometry, which are briefly discussed.