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Sample records for capture dissociation investigated

  1. Electron capture dissociation of singly and multiply phosphorylated peptides

    DEFF Research Database (Denmark)

    Stensballe, A; Jensen, Ole Nørregaard; Olsen, J V; Haselmann, K F; Zubarev, R A

    2000-01-01

    Analysis of phosphotyrosine and phosphoserine containing peptides by nano-electrospray Fourier transform ion cyclotron resonance (FTICR) mass spectrometry established electron capture dissociation (ECD) as a viable method for phosphopeptide sequencing. In general, ECD spectra of synthetic and...... native phosphopeptides appeared less complex than conventional collision activated dissociation (CAD) mass spectra of these species. ECD of multiply protonated phosphopeptide ions generated mainly c- and z(.)-type peptide fragment ion series. No loss of water, phosphate groups or phosphoric acid from...... intact phosphopeptide ions nor from the c and z(.) fragment ion products was observed in the ECD spectra. ECD enabled complete or near-complete amino acid sequencing of phosphopeptides for the assignment of up to four phosphorylation sites in peptides in the mass range 1400 to 3500 Da. Nano-scale Fe...

  2. Collision-induced dissociation and dissociative capture of H2+ in Ar and Kr

    International Nuclear Information System (INIS)

    Measurements of the absolute total and differential cross sections for the production of protons and hydrogen atoms in the energy range of 1-5 keV for reactions of H2+ molecular ions in Ar and Kr targets are reported. The results show that the cross section for the dissociative capture (DC) proccess is about one order of magnitude higher than that for the collision-induced dissociation. The angular distribution of the fragments in both targets and for all acceleration energies shows a monotonic decrease in the differential cross section with increasing angle. A sharp increase in the angular distribution at scattering angles <1.6 deg. is observed for hydrogen atoms resulting from DC and in particular for the Kr target

  3. Electron capture dissociation proceeds with a low degree of intramolecular migration of peptide amide hydrogens

    DEFF Research Database (Denmark)

    Rand, Kasper D; Adams, Christopher M; Zubarev, Roman A;

    2008-01-01

    scrambling) that occurs during vibrational excitation of gas-phase ions. Unlike traditional collisional ion activation, electron capture dissociation (ECD) is not associated with substantial vibrational excitation. We investigated the extent of intramolecular backbone amide hydrogen (1H/2H) migration upon...... electrospray ion source by, e.g., high declustering potentials or during precursor ion selection (via sideband excitation) in the external linear quadrupole ion trap undergo nearly complete hydrogen (1H/2H) scrambling. Similarly, collision-induced dissociation (CID) in the external linear quadrupole ion trap...... closely mimic the known solution deuteration pattern of the selectively labeled peptides. This excellent correlation between the results obtained from gas phase and solution suggests that ECD holds great promise as a general method to obtain single residue resolution in proteins from solution 1H/2H...

  4. Ion induced dissociation of tetraphenyl iron(III) porphyrin chloride and electron-capture induced dissociation of protoporphyrin IX ions

    International Nuclear Information System (INIS)

    We performed experiments concerning the fragmentation of different porphyrin molecules. Multi-ionisation and ion-induced fragmentation of FeTPPCl''q''+ (q = 1 to 4) have been studied in slow collisions with multiply charged ions. We have shown also electron-capture induced dissociation of protoporphyrin cations, where two electrons in two successive have been captured in order to convert it to the corresponding even-electron anions. All fragmentation processes are discussed in terms of charge mobility.

  5. Dissociative electron capture in collisions between Ar8+ and CO2

    International Nuclear Information System (INIS)

    We are using the Cold Target Recoil Ion Spectroscopy (COLTRIMS) to investigate the break up of CO2 molecules in impact processes with slow highly charged ions. While the slow highly charged ions passes the CO2 molecule electron capture into the projectile causes a conformation change of the CO2 molecule. With the COLTRIMS set up we are able to measure the 4π solid angle in momentum space of the dissociating ion fragments. The motivation for this experiment is to ascertain the change of the CO2 molecule conformation

  6. Theory and Application of Dissociative Electron Capture in Molecular Identification

    CERN Document Server

    Havey, C D; Jones, T; Voorhees, K J; Laramee, J A; Cody, R B; Clougherty, D P; Eberhart, Mark; Voorhees, Kent J.; Laramee, James A.; Cody, Robert B.; Clougherty, Dennis P.

    2006-01-01

    The coupling of an electron monochromator (EM) to a mass spectrometer (MS) has created a new analytical technique, EM-MS, for the investigation of electrophilic compounds. This method provides a powerful tool for molecular identification of compounds contained in complex matrices, such as environmental samples. EM-MS expands the application and selectivity of traditional MS through the inclusion of a new dimension in the space of molecular characteristics--the electron resonance energy spectrum. However, before this tool can realize its full potential, it will be necessary to create a library of resonance energy scans from standards of the molecules for which EM-MS offers a practical means of detection. Here, an approach supplementing direct measurement with chemical inference and quantum scattering theory is presented to demonstrate the feasibility of directly calculating resonance energy spectra. This approach makes use of the symmetry of the transition-matrix element of the captured electron to discriminat...

  7. Large scale localization of protein phosphorylation by use of electron capture dissociation mass spectrometry.

    OpenAIRE

    Sweet, Steve M.M.; Bailey, Christopher M; Cunningham, Debbie L.; Heath, John K.; Cooper, Helen J.

    2009-01-01

    We used on-line electron capture dissociation (ECD) for the large scale identification and localization of sites of phosphorylation. Each FT-ICR ECD event was paired with a linear ion trap collision-induced dissociation (CID) event, allowing a direct comparison of the relative merits of ECD and CID for phosphopeptide identification and site localization. Linear ion trap CID was shown to be most efficient for phosphopeptide identification, whereas FT-ICR ECD was superior for localization of si...

  8. Large Scale Localization of Protein Phosphorylation by Use of Electron Capture Dissociation Mass Spectrometry * S⃞

    OpenAIRE

    Sweet, Steve M.M.; Bailey, Christopher M; Cunningham, Debbie L.; Heath, John K.; Cooper, Helen J.

    2009-01-01

    We used on-line electron capture dissociation (ECD) for the large scale identification and localization of sites of phosphorylation. Each FT-ICR ECD event was paired with a linear ion trap collision-induced dissociation (CID) event, allowing a direct comparison of the relative merits of ECD and CID for phosphopeptide identification and site localization. Linear ion trap CID was shown to be most efficient for phosphopeptide identification, whereas FT-ICR ECD was superior for localization of si...

  9. Probing the Mechanism of Electron Capture and Electron Transfer Dissociation Using Tags with Variable Electron Affinity

    OpenAIRE

    Sohn, Chang Ho; Chung, Cheol K.; Yin, Sheng; Ramachandran, Prasanna; Loo, Joseph A; Beauchamp, J. L.

    2009-01-01

    Electron capture dissociation (ECD) and electron transfer dissociation (ETD) of doubly protonated electron affinity (EA)-tuned peptides were studied to further illuminate the mechanism of these processes. The model peptide FQpSEEQQQTEDELQDK, containing a phosphoserine residue, was converted to EA-tuned peptides via β-elimination and Michael addition of various thiol compounds. These include propanyl, benzyl, 4-cyanobenzyl, perfluorobenzyl, 3,5-dicyanobenzyl, 3-nitrobenzyl, and 3,5-dinitrobenz...

  10. The relationship between catatonia and dissociation: A preliminary investigation.

    Science.gov (United States)

    Ross, Colin A; Browning, Elena

    2016-01-01

    Unlike the relationship between dissociation and Schneiderian first-rank symptoms, the relationship between dissociation and catatonia has not been investigated empirically. In order to gather some initial data about catatonia, dissociation, and childhood adverse experiences, we administered the Bush-Francis Catatonia Scale (BFCS), the Dissociative Experiences Scale (DES), the Adverse Childhood Experiences Questionnaire, and the Dissociative Disorders Interview Schedule to 100 inpatients in a hospital trauma program. The average DES score was 44.1 (SD = 22.4), and 86 participants were in the DES-Taxon. The average score on the BFCS was 7.7 (SD = 10.3); 81 participants scored 2 or higher, and 67 scored 5 or higher. The results showed that, in this sample, catatonic symptoms are frequent and related to adverse childhood experiences but seem to be a separate symptom category from both dissociation and psychosis. PMID:26751346

  11. The role of dissociative electron capture in collisions of slow He2+ ions with CO

    International Nuclear Information System (INIS)

    Translational energy spectroscopy (TES) has been used to study one-electron capture by 0.2-1 keV amu-1 He2+ ions in CO and identify, for the first time, the main excited product channels and determine cross sections for both dissociative and non-dissociative processes. Cross sections are shown to be strongly energy dependent over the energy range considered with the contribution from exothermic dissociative electron capture channels associated with He+(1s) formation accounting for about 99% of the total cross section at the lowest energy considered. Endothermic channels arising from non-dissociative one-electron capture have been observed which increase in relative importance as the impact energy increases. These lead to either He+(n=2) or He+(n=3) formation and various states of CO+ with some evidence of vibrational excitation. Of these, the He+(n=2)+CO+[X2Σ+] product channel (with an energy defect ΔE=-0.42 eV) is dominant and this accounts for about 40% of the total cross section at 1 keV amu-1. (author)

  12. Dipole-Guided Electron Capture Causes Abnormal Dissociations of Phosphorylated Pentapeptides

    Science.gov (United States)

    Moss, Christopher L.; Chung, Thomas W.; Wyer, Jean A.; Nielsen, Steen Brøndsted; Hvelplund, Preben; Tureček, František

    2011-04-01

    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 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 low-energy electrons by doubly charged ions in a Penning ion trap induced loss of a hydrogen atom followed by elimination of phosphoric acid as the dominant dissociation channel. Backbone dissociations of charge-reduced ions also occurred but were accompanied by extensive fragmentation of the primary products. z-Ions that were terminated with a deaminated phosphoserine radical competitively eliminated phosphoric acid and H2PO4 radicals. A mechanism is proposed for this novel dissociation on the basis of a computational analysis of reaction pathways and transition states. Electronic structure theory calculations in combination with extensive molecular dynamics 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 in ECD is explained by a distortion of the Rydberg orbital space by the strong dipolar field of the peptide dication framework. The dipolar field steers the incoming electron to preferentially attach to the positively charged arginine side chain to form guanidinium radicals and trigger their dissociations.

  13. Evaluation and optimization of electron capture dissociation efficiency in fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    McFarland, Melinda A; Chalmers, Michael J; Quinn, John P; Hendrickson, Christopher L; Marshall, Alan G

    2005-07-01

    Electron capture dissociation (ECD) efficiency has typically been lower than for other dissociation techniques. Here we characterize experimental factors that limit ECD and seek to improve its efficiency. Efficiency of precursor to product ion conversion was measured for a range of peptide (approximately 15% efficiency) and protein (approximately 33% efficiency) ions of differing sizes and charge states. Conversion of precursor ions to products depends on electron irradiation period and maximizes at approximately 5-30 ms. The optimal irradiation period scales inversely with charge state. We demonstrate that reflection of electrons through the ICR cell is more efficient and robust than a single pass, because electrons can cool to the optimal energy for capture, which allows for a wide range of initial electron energy. Further, efficient ECD with reflected electrons requires only a short (approximately 500 micros) irradiation period followed by an appropriate delay for cooling and interaction. Reflection of the electron beam results in electrons trapped in or near the ICR cell and thus requires a brief (approximately 50 micros) purge for successful mass spectral acquisition. Further electron irradiation of refractory precursor ions did not result in further dissociation. Possibly the ion cloud and electron beam are misaligned radially, or the electron beam diameter may be smaller than that of the ion cloud such that remaining precursor ions do not overlap with the electron beam. Several ion manipulation techniques and use of a large, movable dispenser cathode reduce the possibility that misalignment of the ion and electron beams limits ECD efficiency. PMID:15914017

  14. Hydrogen rearrangement to and from radical z fragments in electron capture dissociation of peptides

    DEFF Research Database (Denmark)

    Savitski, Mikhail M; Kjeldsen, Frank; Nielsen, Michael L;

    2007-01-01

    capture dissociation (ECD), including previously unreported double H. losses. Consistent with the radical character of H. abstraction, the residue determining the formation rate of z' = z. + H. species is found to be the N-terminal residue in z. species. The size of the complementary c(m)' fragment turned...... out to be another important factor, with z' species dominating over z. ions for m

  15. Rapid electron capture dissociation of mass-selectively accumulated oligodeoxynucleotide dications

    Science.gov (United States)

    Schultz, Kristin N.; Håkansson, Kristina

    2004-05-01

    We have performed extended characterization of the fragmentation patterns of oligodeoxynucleotide dications following electron capture dissociation (ECD) utilizing improved instrumentation. Our current results from a 9.4 T Fourier transform ion cyclotron resonance mass spectrometer equipped with mass-selective external ion accumulation and an indirectly heated dispenser cathode electron source demonstrate much richer fragmentation than from a previous 7 T instrument with a directly heated filament electron source. We propose the previous absence of backbone product ions from purine-containing oligonucleotides is a result of intramolecular hydrogen bonding, preventing product ions from separating. Similar behavior is observed at non-optimized ECD conditions with the current instrumentation. However, infrared laser heating of the resulting charge-reduced radical species results in extensive backbone fragmentation (different from infrared multiphoton dissociation) of the oligonucleotide dA6, demonstrating potential for ECD to characterize nucleic acid secondary structure. Under more optimized conditions, rich fragmentation, mostly in terms of w, (a/z-B), and (c/x-B) products, is observed for dA6, dC6, dG5, and d(GCATGC) following ECD only, allowing complete sequencing in several cases. The current ECD spectra contain some doubly charged products, indicating that populations of gas-phase oligodeoxynucleotide dications are zwitterionic.

  16. Advantages of external accumulation for electron capture dissociation in Fourier transform mass spectrometry.

    Science.gov (United States)

    Haselmann, K F; Budnik, B A; Olsen, J V; Nielsen, M L; Reis, C A; Clausen, H; Johnsen, A H; Zubarev, R A

    2001-07-01

    A combination of external accumulation (XA) with electron capture dissociation (ECD) improves the electron capture efficiency, shortens the analysis time, and allows for rapid integration of multiple scans in Fourier transform mass spectrometry. This improves the signal-to-noise ratio and increases the number of detected products, including structurally important MS3 fragments. With XA-ECD, the range of the labile species amenable to ECD is significantly extended. Examples include the first-time determination of the positions of six GalNAc groups in a 60-residue peptide, five sialic acid and six O-linked GalNAc groups in a 25-residue peptide, and the sulfate group position in a 11-residue peptide. Even weakly bound supramolecular aggregates, including nonspecific peptide complexes, can be analyzed with XA-ECD. Preliminary results are reported on high-rate XA-ECD that uses an indirectly heated dispenser cathode as an electron source. This shortens the irradiation time to > or = 1 ms and increases the acquisition rate to 3 scans/s, an improvement by a factor of 10-100. PMID:11467546

  17. Combined infrared multiphoton dissociation and electron-capture dissociation using co-linear and overlapping beams in Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Mihalca, Romulus; van der Burgt, Yuri E M; McDonnell, Liam A; Duursma, Marc; Cerjak, Iliya; Heck, Albert J R; Heeren, Ron M A

    2006-01-01

    A novel set-up for Fourier transform ion cyclotron resonance mass spectrometry (FTICR) is reported for simultaneous infrared multiphoton dissociation (IRMPD) and electron-capture dissociation (ECD). An unmodified electron gun ensures complete, on-axis overlap between the electron and the photon beams. The instrumentation, design and implementation of this novel approach are described. In this configuration the IR beam is directed into the ICR cell using a pneumatically actuated mirror inserted into the ion-optical path. Concept validation was made using different combinations of IRMPD and ECD irradiation events on two standard peptides. The ability to perform efficient IRMPD, ECD and especially simultaneous IRMPD and ECD using lower irradiation times is demonstrated. The increase in primary sequence coverage, with the combined IRMPD and ECD set-up, also increases the confidence in peptide and protein assignments. PMID:16705647

  18. Dissociative electron capture by halogenated alkanes and kinetics of the low energy electron attachment by chloroalkanes

    International Nuclear Information System (INIS)

    Data are presented for a series of halogen containing hydrocarbons closely related to the freon molecules studied by the use of electron capture negative ion mass spectrometry. Temperature dependence of negative ion effective yield is discussed. Thermal electron attachment processes in the mixtures of chloroalkanes with carbon dioxide have been investigated using an electron swarm method. All of them (except CH2Cl2) attach electrons only in a two-body process. Corresponding rate constants have been determined. (author)

  19. Probing the Electron Capture Dissociation Mass Spectrometry of Phosphopeptides with Traveling Wave Ion Mobility Spectrometry and Molecular Dynamics Simulations

    OpenAIRE

    Kim, Doyong; Pai, Pei-Jing; Creese, Andrew J.; Jones, Andrew W.; Russell, David H.; Cooper, Helen J.

    2015-01-01

    Electron capture dissociation mass spectrometry offers several advantages for the analysis of peptides, most notably that backbone c and z fragments typically retain labile modifications such as phosphorylation. We have shown previously that, in some cases, the presence of phosphorylation has a deleterious effect on peptide sequence coverage, and hypothesized that intramolecular interactions involving the phosphate group were preventing separation of backbone fragments. In the present work, w...

  20. Capture cross-section and rate of the 14C(, )15C reaction from the Coulomb dissociation of 15C

    Indian Academy of Sciences (India)

    Shubhchintak; Neelam; R Chatterjee

    2014-10-01

    We calculate the Coulomb dissociation of 15C on a Pb target at 68 MeV/u incident beam energy within the fully quantum mechanical distorted wave Born approximation formalism of breakup reactions. The capture cross-section and the subsequent rate of the 14C(, )15C reaction are calculated from the photodisintegration of 15C, using the principle of detailed balance. Our theoretical model is free from the uncertainties associated with the multipole strength distributions of the projectile.

  1. Combined infrared multiphoton dissociation and electron capture dissociation with a hollow electron beam in Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Tsybin, Youri O; Witt, Matthias; Baykut, Gökhan; Kjeldsen, Frank; Håkansson, Per

    2003-01-01

    An electron injection system based on an indirectly heated ring-shaped dispenser cathode has been developed and installed in a 7 Tesla Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. This new hardware design allows high-rate electron capture dissociation (ECD) to be carried out by a hollow electron beam coaxial with the ion cyclotron resonance (ICR) trap. Infrared multiphoton dissociation (IRMPD) can also be performed with an on-axis IR-laser beam passing through a hole at the centre of the dispenser cathode. Electron and photon irradiation times of the order of 100 ms are required for efficient ECD and IRMPD, respectively. As ECD and IRMPD generate fragments of different types (mostly c, z and b, y, respectively), complementary structural information that improves the characterization of peptides and proteins by FTICR mass spectrometry can be obtained. The developed technique enables the consecutive or simultaneous use of the ECD and IRMPD methods within a single FTICR experimental sequence and on the same ensemble of trapped ions in multistage tandem (MS/MS/MS or MS(n)) mass spectrometry. Flexible changing between ECD and IRMPD should present advantages for the analysis of protein digests separated by liquid chromatography prior to FTICRMS. Furthermore, ion activation by either electron or laser irradiation prior to, as well as after, dissociation by IRMPD or ECD increases the efficiency of ion fragmentation, including the w-type fragment ion formation, and improves sequencing of peptides with multiple disulfide bridges. The developed instrumental configuration is essential for combined ECD and IRMPD on FTICR mass spectrometers with limited access into the ICR trap. PMID:12872281

  2. An experimental investigation of the dissociative ionization process of argon cluster ions induced by electron impact

    International Nuclear Information System (INIS)

    Utilizing the Cold Target Recoil Ions Momentum Spectrometer (COLTRIMS), dissociative ionization of argon cluster was experimentally investigated by electron impact. The recoil ions produced both in the pure ionization process and the dissociative ionization channels are measured with collision energies from 100 and 1000 eV. The ratios of the dimer ions from pure ionization (Ar2P+) and the dimer ions from small cluster dissociation (Ar+2D) to the atomic argon ion (Ar+) in different stagnation pressures were obtained.

  3. The investigation of photo-dissociation by time dependent quantum method

    International Nuclear Information System (INIS)

    The fragmentation of a bound molecule through absorption of one or more photons is called photo-dissociation. The electromagnetic energy of the light beam is converted into internal energy of the molecule and if the transferred energy exceeds the binding energy of the weakest bond, the molecule will irreversible break apart. Let us, as an example, consider the dissociation of a parent molecule AB into products A and B, where A and B represent either structureless atoms or molecules with internal degrees of freedom of their own. Formally we write a photo-dissociation process as, AB+Nphotonℎω→(AB)*→A(α)+B(β) Photo-dissociation can be roughly classified as either direct or indirect dissociation. In a direct process the parent molecule dissociates immediately after the photon has promoted it to the upper electronic state. No well or other dynamical constraint hinders the fragmentation and the 'lifetime' of the excited complex is very short, less than a vibrational period within the complex. In indirect photo-fragmentation, on the other hand, a potential well or some other dynamical force hinders direct fragmentation of the excited complex and the lifetime amounts to at least several internal vibrational periods. Photo-dissociation is one of the important topics of quantum chemistry. The basic principles of photo-dissociation and the time dependent quantum wave packet method, which is one of the methods developed to investigate dissociation have been applied to this study, which the dissociations of NH+ and HCl molecules.

  4. Reply to comments on `Structure effects in the $^{15}$N($n,\\gamma$)$^{16}$N radiative capture reaction from the Coulomb dissociation of $^{16}$N'

    CERN Document Server

    Shubhchintak,; Chatterjee, R

    2016-01-01

    We reply to the comments (arXiv:1605.07499 [nucl-th]) on "Structure effects in the $^{15}$N($n,\\gamma$)$^{16}$N radiative capture reaction from the Coulomb dissociation of $^{16}$N". We have investigated the issue of "energy dependence of branching ratios" and believe that this energy dependence is due to the proper inclusion of the non-resonant continuum in the post-form reaction theory. Interestingly, this energy dependence is sensitive to the relative orbital angular momentum content of the state. We reiterate that we have attempted to resolve the discrepancy in the spectroscopic factors of low-lying $^{16}$N levels and that it is essential to know the low energy $^{15}$N($n,\\gamma$)$^{16}$N capture cross section, especially below 0.25 MeV.

  5. Semiempirical and DFT Investigations of the Dissociation of Alkyl Halides

    Science.gov (United States)

    Waas, Jack R.

    2006-01-01

    Enthalpy changes corresponding to the gas phase heats of dissociation of 12 organic halides were calculated using two semiempirical methods, the Hartree-Fock method, and two DFT methods. These calculated values were compared to experimental values where possible. All five methods agreed generally with the expected empirically known trends in the…

  6. DNA hybridization on microparticles: determining capture-probe density and equilibrium dissociation constants.

    OpenAIRE

    Wilkins Stevens, P; Henry, M. R.; Kelso, D M

    1999-01-01

    Many DNA-probe assays utilize oligonucleotide-coated microparticles for capture of complementary nucleic acids from solution. During development of these assays, as well as in other particle-based nucleic acid applications, it is useful to know both the amount of duplex formation expected under various experimental conditions and the coating density of the capture oligonucleotide on the particle surface. We examined the simplest form of a DNA-probe microparticle assay: hybridization of a part...

  7. Dipole-Guided Electron Capture Causes Abnormal Dissociations of Phosphorylated Pentapeptides

    DEFF Research Database (Denmark)

    Moss, Christopher L.; Chung, Thomas W.; Wyer, Jean; Nielsen, Steen Brøndsted; Hvelplund, Preben; Turecek, Frantisek

    2011-01-01

    phosphoserine radical competitively eliminated phosphoric acid and H2PO4 radicals. A mechanism is proposed for this novel dissociation on the basis of a computational analysis of reaction pathways and transition states. Electronic structure theory calculations in combination with extensive molecular dynamics...... in ECD is explained by a distortion of the Rydberg orbital space by the strong dipolar field of the peptide dication framework. The dipolar field steers the incoming electron to preferentially attach to the positively charged arginine side chain to form guanidinium radicals and trigger their...

  8. Structure effects in the 15N(n ,γ )16N radiative capture reaction from the Coulomb dissociation of 16N

    Science.gov (United States)

    Neelam, Shubhchintak, Chatterjee, R.

    2015-10-01

    Background: The 15N(n ,γ )16N reaction plays an important role in red giant stars and also in inhomogeneous big bang nucleosynthesis. However, there are controversies regarding spectroscopic factors of the four low-lying states of 16N, which have direct bearing on the total direct capture cross section and also on the reaction rate. Direct measurements of the capture cross section at low energies are scarce and available only at three energies below 500 keV. Purpose: The aim of this paper is to calculate the 15N(n ,γ )16N radiative capture cross section and its subsequent reaction rate by an indirect method and in that process investigate the effects of spectroscopic factors of different levels of 16N to the cross section. Method: A fully quantum mechanical Coulomb breakup theory under the aegis of post-form distorted wave Born approximation is used to calculate the Coulomb breakup of 16N on Pb at 100 MeV/u . This is then related to the photodisintegration cross section of 16N(γ ,n )15N and subsequently invoking the principle of detailed balance, the 15N(n ,γ )16N capture cross section is calculated. Results: The nonresonant capture cross section is calculated with spectroscopic factors from the shell model and those extracted (including uncertainties) from two recent experiments. The data seem to favor a more single particle nature for the low-lying states of 16N. The total neutron capture rate is also calculated by summing up nonresonant and resonant (significant only at temperatures greater than 1 GK) contributions and comparison is made with other charged particle capture rates. In the typical temperature range of 0.1 -1.2 GK, almost all the contributions to the reaction rate come from capture cross sections below 0.25 MeV. Conclusion: We have attempted to resolve the discrepancy in the spectroscopic factors of low-lying 16N levels and conclude that it would certainly be useful to perform a Coulomb dissociation experiment to find the low energy capture

  9. Probing the Electron Capture Dissociation Mass Spectrometry of Phosphopeptides with Traveling Wave Ion Mobility Spectrometry and Molecular Dynamics Simulations

    Science.gov (United States)

    Kim, Doyong; Pai, Pei-Jing; Creese, Andrew J.; Jones, Andrew W.; Russell, David H.; Cooper, Helen J.

    2015-06-01

    Electron capture dissociation mass spectrometry offers several advantages for the analysis of peptides, most notably that backbone c and z fragments typically retain labile modifications such as phosphorylation. We have shown previously that, in some cases, the presence of phosphorylation has a deleterious effect on peptide sequence coverage, and hypothesized that intramolecular interactions involving the phosphate group were preventing separation of backbone fragments. In the present work, we seek to rationalize the observed ECD behavior through a combination of ECD of model peptides, traveling wave ion mobility mass spectrometry and molecular dynamics simulations. The results suggest that for doubly protonated ions of phosphopeptide APLpSFRGSLPKSYVK a salt-bridge structure is favored, whereas for the doubly-protonated ions of APLSFRGSLPKpSYVK ionic hydrogen bonds predominate.

  10. Determining the Binding Sites of β-Cyclodextrin and Peptides by Electron-Capture Dissociation High Resolution Tandem Mass Spectrometry

    Science.gov (United States)

    Qi, Yulin; Geib, Timon; Volmer, Dietrich A.

    2015-07-01

    Cyclodextrins (CDs) are a group of cyclic oligosaccharides, which readily form inclusion complexes with hydrophobic compounds to increase bioavailability, thus making CDs ideal drug excipients. Recent studies have also shown that CDs exhibit a wide range of protective effects, preventing proteins from aggregation, degradation, and folding. These effects strongly depend on the binding sites on the protein surface. CDs only exhibit weak interactions with amino acids, however; conventional analytical techniques therefore usually fail to reveal the exact location of the binding sites. Moreover, some studies even suggest that CD inclusion complexes are merely electrostatic adducts. Here, electron capture dissociation (ECD) was applied in this proof-of-concept study to examine the exact nature of the CD/peptide complexes, and CD binding sites were unambiguously located for the first time via Fourier-transform ion cyclotron resonance (FTICR) tandem mass spectrometry.

  11. Comment on "Structure effects in the $^{15}$N(n,$\\gamma$)$^{16}$N radiative capture reaction from the Coulomb dissociation of $^{16}$N"

    CERN Document Server

    Mohr, Peter

    2016-01-01

    In their recent study Neelam, Shubhchintak, and Chatterjee have claimed that "it would certainly be useful to perform a Coulomb dissociation experiment to find the low energy capture cross section for the reaction" $^{15}$N(n,$\\gamma$)$^{16}$N. However, it is obvious that a Coulomb dissociation experiment cannot constrain this capture cross section because the dominating branchings of the capture reaction lead to excited states in $^{16}$N which do not contribute in a Coulomb dissociation experiment. An estimate of the total $^{15}$N(n,$\\gamma$)$^{16}$N cross section from Coulomb dissociation of $^{16}$N requires a precise knowledge of the $\\gamma$-ray branchings in the capture reaction. Surprisingly, the calculation of Neelam, Shubhchintak, and Chatterjee predicts a strongly energy-dependent ground state branching of the order of 0.05\\% to 0.6\\% at energies between 100 and 500 keV which is almost 2 orders of magnitude below calculations in the direct capture model. Additionally, this calculation of Neelam, S...

  12. Difference of Electron Capture and Transfer Dissociation Mass Spectrometry on Ni2+-, Cu2+-, and Zn2+-Polyhistidine Complexes in the Absence of Remote Protons

    Science.gov (United States)

    Asakawa, Daiki; De Pauw, Edwin

    2016-07-01

    Electron capture dissociation (ECD) and electron transfer dissociation (ETD) in metal-peptide complexes are dependent on the metal cation in the complex. The divalent transition metals Ni2+, Cu2+, and Zn2+ were used as charge carriers to produce metal-polyhistidine complexes in the absence of remote protons, since these metal cations strongly bind to neutral histidine residues in peptides. In the case of the ECD and ETD of Cu2+-polyhistidine complexes, the metal cation in the complex was reduced and the recombination energy was redistributed throughout the peptide to lead a zwitterionic peptide form having a protonated histidine residue and a deprotonated amide nitrogen. The zwitterion then underwent peptide bond cleavage, producing a and b fragment ions. In contrast, ECD and ETD induced different fragmentation processes in Zn2+-polyhistidine complexes. Although the N-Cα bond in the Zn2+-polyhistidine complex was cleaved by ETD, ECD of Zn2+-polyhistidine induced peptide bond cleavage accompanied with hydrogen atom release. The different fragmentation modes by ECD and ETD originated from the different electronic states of the charge-reduced complexes resulting from these processes. The details of the fragmentation processes were investigated by density functional theory.

  13. Electron capture dissociation and drift tube ion mobility-mass spectrometry coupled with site directed mutations provide insights into the conformational diversity of a metamorphic protein

    OpenAIRE

    Harvey, Sophie R.; Porrini, Massimiliano; Tyler, Robert C.; MacPhee, Cait E.; Volkman, Brian F.; Barran, Perdita E.

    2015-01-01

    Ion mobility mass spectrometry can be combined with data from top-down sequencing to discern adopted conformations of proteins in the absence of solvent. This multi-technique approach has particular applicability for conformationally dynamic systems. Previously, we demonstrated the use of drift tube ion mobility-mass spectrometry (DT IM-MS) and electron capture dissociation (ECD) to study the metamorphic protein lymphotactin (Ltn). Ltn exists in equilibrium between distinct monomeric (Ltn10) ...

  14. Investigation into thermal dissociation of A2B5 group semiconductors

    International Nuclear Information System (INIS)

    Thermal dissociation of the A2B5 group compounds is investigated. It is shown that evaporation mechanism is determined by diffusion processes. These compounds are evaporated congruently under dynamic conditions. Diffusion coefficients of phosphorus in CdP4(1.4x10-18 cm2/s at 592 K) and arsenic in CdAs2(7x10-17 cm2/s at 640 K) are evaluated

  15. Nanosolvation by acetonitrile and 18-crown-6 ether induce strongly different effects on the electron-capture induced dissociation of aromatic tripeptide cations in the gas phase

    DEFF Research Database (Denmark)

    MacLot, S.; Rangama, J.; Nielsen, Steen Brøndsted; Poully, J.-C.

    2013-01-01

    Experimental gas-phase Electron Capture-Induced Dissociation (ECID) coupled to mass-spectrometry has been performed on the doubly-protonated tripeptides Lys-Trp-Lys (KWK) and Lys-Tyr-Lys (KYK). In this report, we focus on the influence of non-covalent binding of two different molecules, acetonitr......Experimental gas-phase Electron Capture-Induced Dissociation (ECID) coupled to mass-spectrometry has been performed on the doubly-protonated tripeptides Lys-Trp-Lys (KWK) and Lys-Tyr-Lys (KYK). In this report, we focus on the influence of non-covalent binding of two different molecules......, acetonitrile and 18-crown-6 ether (CE), to these tripeptide cations on the relative probabilities of their main fragmentation channels (H loss, NH3 loss and N — Cα bond cleavage) after electron capture from sodium atoms. First, we recorded the spectra of bare peptide ions, and found that N — Cα bond cleavage...... by one and two molecules show that acetonitrile evaporation is almost complete a few microseconds after electron capture, whereas fragments nanosolvated by CE are abundant. This is consistent with the binding energy of these molecules to lysine-containing peptides, which is much higher for CE than...

  16. Investigation of light nuclei by particle capture and resonant absorption

    International Nuclear Information System (INIS)

    This thesis describes measurements of properties of selected nuclear levels, which are relevant to model-descriptions (like some low-lying states of 39K and 41Sc) or to experimental procedures (like the calibration of gamma-ray detector efficiencies). These experiments often yield additional information on many other levels. The author discusses examples of proton- and deuteron-capture reactions and of γ-ray absorption experiments. The author describes experiments to determine the spins and parities of the Ex = 3.88 and 4.13 MeV levels of 39K; to determine the spins and parities of the second and third excited state of 41Sc; and a study of deuteron-capture and γ-ray resonant-absorption reactions used to investigate the Ex = 16.98 MeV, T = 3/2 level of 9Be. A new technique is described that produces γ-rays of which the energy is tuneable. (Auth.)

  17. Pharmacological Investigations of the Dissociative 'Legal Highs' Diphenidine, Methoxphenidine and Analogues.

    Science.gov (United States)

    Wallach, Jason; Kang, Heather; Colestock, Tristan; Morris, Hamilton; Bortolotto, Zuner A; Collingridge, Graham L; Lodge, David; Halberstadt, Adam L; Brandt, Simon D; Adejare, Adeboye

    2016-01-01

    1,2-Diarylethylamines including lanicemine, lefetamine, and remacemide have clinical relevance in a range of therapeutic areas including pain management, epilepsy, neurodegenerative disease and depression. More recently 1,2-diarylethylamines have been sold as 'legal highs' in a number of different forms including powders and tablets. These compounds are sold to circumvent governmental legislation regulating psychoactive drugs. Examples include the opioid MT-45 and the dissociative agents diphenidine (DPH) and 2-methoxy-diphenidine (2-MXP). A number of fatal and non-fatal overdoses have been linked to abuse of these compounds. As with many 'legal highs', little is known about their pharmacology. To obtain a better understanding, the effects of DPH, 2-MXP and its 3- and 4-MeO- isomers, and 2-Cl-diphenidine (2-Cl-DPH) were investigated using binding studies at 46 central nervous system receptors including the N-methyl-D-aspartate receptor (NMDAR), serotonin, dopamine, norepinephrine, histamine, and sigma receptors as well as the reuptake transporters for serotonin, dopamine and norepinephrine. Reuptake inhibition potencies were measured at serotonin, norepinephrine and dopamine transporters. NMDAR antagonism was established in vitro using NMDAR-induced field excitatory postsynaptic potential (fEPSP) experiments. Finally, DPH and 2-MXP were investigated using tests of pre-pulse inhibition of startle (PPI) in rats to determine whether they reduce sensorimotor gating, an effect observed with known dissociative drugs such as phencyclidine (PCP) and ketamine. The results suggest that these 1,2-diarylethylamines are relatively selective NMDAR antagonists with weak off-target inhibitory effects on dopamine and norepinephrine reuptake. DPH and 2-MXP significantly inhibited PPI. DPH showed greater potency than 2-MXP, acting with a median effective dose (ED50) of 9.5 mg/kg, which is less potent than values reported for other commonly abused dissociative drugs such as PCP and

  18. Conversion of 3-nitrotyrosine to 3-aminotyrosine residues facilitates mapping of tyrosine nitration in proteins by electrospray ionization-tandem mass spectrometry using electron capture dissociation.

    Science.gov (United States)

    Guo, Jia; Prokai, Laszlo

    2012-12-01

    Protein tyrosine nitration is associated with oxidative stress and various human diseases. Tandem mass spectrometry has been the method of choice for the identification and localization of this posttranslational modification to understand the underlying mechanisms and functional consequences. Due to the electron predator effect of the nitro group limiting fragmentation of the peptide backbone, electron-based dissociation has not been applicable, however, to nitrotyrosine-containing peptides. A straightforward conversion of the nitrotyrosine to the aminotyrosine residues is introduced to address this limitation. When tested with nitrated ubiquitin and human serum albumin as model proteins in top-down and bottom-up approaches, respectively, this chemical derivatization enhanced backbone fragmentation of the corresponding nitroproteins and nitropeptides by electron capture dissociation (ECD). Increased sequence coverage has been obtained by combining in the bottom-up strategy the conversion of nitrotyrosine to aminotyrosine and introducing, in addition to trypsin, a further digesting enzyme of complementary specificity, when protein nitration was mapped by liquid chromatography-electrospray ionization tandem mass spectrometry using both collision-induced dissociation (CID) and ECD. PMID:23280749

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

    Science.gov (United States)

    Kjeldsen, Frank; Haselmann, Kim F; Sørensen, Esben S; Zubarev, Roman A

    2003-03-15

    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 isomeric Ile and Leu residues. The analytical utility of HECD is evaluated using tryptic peptides from the bovine milk protein PP3 containing totally 135 amino acid residues. Using a formal procedure for Ile/Leu (Xle) residue assignment, the identities of 20 out of 25 Xle residues (80%) were determined. The identity of an additional two residues could be correctly guessed from the absence of the alternative w ions, and only two residues, for which neither expected nor alternative w ions were observed, remained unassigned. Reinspection of conventional ECD spectra also revealed the presence of Xle w ions, although at lower abundances, with 44% of all Xle residues distinguished. Using a dispenser cathode as an electron source, identification of four out of five Xle residues in a 2.7-kDa peptide was possible with one acquisition 2 s long, with identification of all five residues by averaging of five such acquisitions. Unlike the case of high-energy collision-induced dissociation, no d ions were observed in the HECD of tryptic peptides. PMID:12659185

  20. Combined electron capture and infrared multiphoton dissociation for multistage MS/MS in a Fourier transform ion cyclotron resonance mass spectrometer.

    Science.gov (United States)

    Håkansson, Kristina; Chalmers, Michael J; Quinn, John P; McFarland, Melinda A; Hendrickson, Christopher L; Marshall, Alan G

    2003-07-01

    We have mounted a permanent on-axis dispenser cathode electron source inside the magnet bore of a 9.4-T Fourier transform ion cyclotron resonance mass spectrometer. This configuration allows electron capture dissociation (ECD) to be performed reliably on a millisecond time scale. We have also implemented an off-axis laser geometry that enables simultaneous access to ECD and infrared multiphoton dissociation (IRMPD). Optimum performance of both fragmentation techniques is maintained. The analytical utility of performing either ECD or IRMPD on a given precursor ion population is demonstrated by structural characterization of several posttranslationally modified peptides: IRMPD of phosphorylated peptides results in few backbone (b- and y-type) cleavages, and product ion spectra are dominated by neutral loss of H3PO4. In contrast, ECD provides significantly more backbone (c- and z*-type) cleavages without loss of H3PO4. For N-glycosylated tryptic peptides, IRMPD causes extensive cleavage of the glycosidic bonds, providing structural information about the glycans. ECD cleaves all backbone bonds (except the N-terminal side of proline) in a 3-kDa glycopeptide with no saccharide loss. However, only a charge-reduced radical species and some side chain losses are observed following ECD of a 5-kDa glycopeptide from the same protein. An MS3 experiment involving IR laser irradiation of the charge-reduced species formed by electron capture results in extensive dissociation into c- and z-type fragment ions. Mass-selective external ion accumulation is essential for the structural characterization of these low-abundance (modified) peptides. PMID:12964777

  1. Investigations of acidity and nucleophilicity of diphenyldithiophosphinate ligands using theory and gas-phase dissociation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Christopher M. Leavitt; Garold L. Gresham; Michael T. Benson; Jean-Jaques Gaumet; Dean Peterman; John Klaehn; Megan Moser; Frederic Aubriet; Michael J. Van Stipdonk; Gary S. Groenewold

    2008-04-01

    Diphenyldithiophosphinate (DTP) ligands modified with electron-withdrawing trifluoromethyl (TFM) substitutents are of high interest because they have demonstrated potential for exceptional separation of Am3+ from lanthanide3+ cations. Specifically, the bis(ortho-TFM) (L1-) and (ortho-TFM)(meta-TFM) (L2-) derivatives have shown excellent separation selectivity, while the bis(meta-TFM) (L3)- and unmodified DTP (Lu-) did not. Factors responsible for selective coordination have been investigated using density functional theory (DFT) calculations in concert with competitive dissociation reactions in the gas phase. To evaluate the role of (DTP+H) acidity, density functional calculations were used to predict pKa values, which followed the trend of L3 < L2 < L1 < Lu. The order of the TFM-modified (DTP+H) acids was opposite of what would be expected based on the e--withdrawing effects of the TFM group, suggesting that secondary factors are influencing the pKa and nucleophilicity. The relative nucleophilicities of the DTP anions were evaluated by forming metal-mixed ligand complexes in a trapped ion mass spectrometer, and then fragmenting them using competitive collision induced dissociation. Relative to Na+, the unmodified Lu- anion was the strongest nucleophile. Comparing the TFM derivatives, the bis(ortho-TFM) derivative L1- was found to be the strongest nucleophile, while the bis(meta-TFM) L3- was the weakest, a trend consistent with the pKa calculations. DFT modeling of the Na+ complexes suggested that the elevated cation affinity of the L1- and L2- anions was due to donation of electron density from fluorine atoms to the metal center, which was occurring in rotational conformers where the TFM moiety was proximate to the Na+-dithiophosphinate group. Competitive dissociation experiments were performed with the dithiophosphinate anions complexed with europium nitrate species; ionic dissociation of these complexes always produced the TFM-modified dithiophosphinate anions

  2. An investigation into a suitable scintillator for localising neutron capture within a detector

    OpenAIRE

    Balmer, Matthew; Gamage, Kelum; Taylor, Graeme

    2014-01-01

    Using Monte-Carlo modelling, an investigation into a suitable loaded scintillator for localising neutron capture in a novel neutron survey meter has been undertaken. A comparison of estimated neutron capture location in a scintillator with Geant4 and MCNP simulations was undertaken and a good general agreement between the two models was observed. The interactions of γ emissions from neutron capture in the scintillator are investigated. The results show that the γ emission from neutron capture...

  3. Investigation of linguistic comprehension processing by capture software

    Directory of Open Access Journals (Sweden)

    Vera Wannmacher Pereira

    2015-01-01

    Full Text Available Among many computer tools that are provided for research development, especially with regard to language, the capture software technologies are important for the study of cognitive processes while performing activities using the computer as an electronic support. This article presents one – the capture software SnagIt – which records videos of the user's movements with the mouse, during the linguistic comprehension process, enabling analysis and reflections on the user’s journey and thereby their cognitive processing. Two psycholinguistic studies developed at the Reference Center for Language Development – CELIN/ FALE/ PUCRS – used this capture software in order to examine the linguistic comprehension strategies applied by the subjects. These studies are presented for demonstration and explanation.

  4. Differential dissociation micromethod for the investigation of binding of metandrostenolone (Nerobol) to plasma proteins

    Energy Technology Data Exchange (ETDEWEB)

    Bojadzsieva, M.; Kocsar, L. (Orszagos Frederic Joliot-Curie Sugarbiologiai es Sugaregeszseguegyi Kutato Intezet, Budapest (Hungary)); Kremmer, T. (Orszagos Onkologiai Intezet, Budapest (Hungary))

    1985-01-01

    A micromethod was developed to determine the binding of anabolic steroids to plasma proteins. The new procedure combines precipitation with ammonium sulphate and differential dissociation. The binding parameters (association constant, specific binding capacity) are calculated on the basis of dissociation curves of sup(3)H-metandrostenolone from the precipitated sexual binding globuline.

  5. Investigation of Synaptic Tagging/Capture and Cross-capture using Acute Hippocampal Slices from Rodents.

    Science.gov (United States)

    Shetty, Mahesh Shivarama; Sharma, Mahima; Hui, Neo Sin; Dasgupta, Ananya; Gopinadhan, Suma; Sajikumar, Sreedharan

    2015-01-01

    Synaptic tagging and capture (STC) and cross-tagging are two important mechanisms at cellular level that explain how synapse-specificity and associativity is achieved in neurons within a specific time frame. These long-term plasticity-related processes are the leading candidate models to study the basis of memory formation and persistence at the cellular level. Both STC and cross-tagging involve two serial processes: (1) setting of the synaptic tag as triggered by a specific pattern of stimulation, and (2) synaptic capture, whereby the synaptic tag interacts with newly synthesized plasticity-related proteins (PRPs). Much of the understanding about the concepts of STC and cross-tagging arises from the studies done in CA1 region of the hippocampus and because of the technical complexity many of the laboratories are still unable to study these processes. Experimental conditions for the preparation of hippocampal slices and the recording of stable late-LTP/LTD are extremely important to study synaptic tagging/cross-tagging. This video article describes the experimental procedures to study long-term plasticity processes such as STC and cross-tagging in the CA1 pyramidal neurons using stable, long-term field-potential recordings from acute hippocampal slices of rats. PMID:26381286

  6. Mass spectral investigations of boron neutron capture therapy (BNCT) agents

    International Nuclear Information System (INIS)

    Boron neutron capture therapy (BNCT) is a promising technique for the treatment of selected types of brain tumor and potentially for other tumor types. In this therapy, a 10B-enriched species is administered to the bloodstream and selectively deposited in the tumor. The selective deposition in the tumor is due to either the breakdown of the blood-grain barrier or to the chemical nature of the boron-containing compounds. Once a sufficient concentration of boron is attained in the tumor (approximately 25 ppm), the tumor is irradiated with a controlled energy neutron beam (preferable epithermal, 1 eV to 10 keV), at which time neutrons are captured by the incorporated boron atoms. The capture results in the reaction, 10B(n, ) Li, which produces a localized nuclear reaction capable of destroying the tumor cell containing the boron. A variety of boron containing compounds have been evaluated for use in BNCT. This paper addresses some of the most promising of the compounds, the disodium salt of mercaptoundecahydrododecaborate (Na2B12H11SH), commonly referred to as BSH

  7. Experimental investigation on the dissociation conditions of methane hydrate in the presence of imidazolium-based ionic liquids

    International Nuclear Information System (INIS)

    Highlights: • Study on thermodynamic effect of ionic liquids on methane hydrate (liquid + vapour) equilibrium line (HLVE). • The performance of ionic liquid as new class of gas hydrate inhibitor is investigated. • Conductivity and pH effect of ionic liquid on gas hydrate inhibition. • HPμDSC measurements of methane hydrate dissociation temperature. • The dissociation enthalpy of methane hydrate is calculated. - Abstract: In this work, the performance of nine ionic liquids (ILs) as thermodynamic hydrate inhibitors is investigated. The dissociation temperature is determined for methane gas hydrates using a high pressure micro deferential scanning calorimeter between (3.6 and 11.2) MPa. All the aqueous IL solutions are studied at a mass fraction of 0.10. The performance of the two best ILs is further investigated at various concentrations. Electrical conductivity and pH of these aqueous IL solutions (0.10 mass fraction) are also measured. The enthalpy of gas hydrate dissociation is calculated by the Clausius–Clapeyron equation. It is found that the ILs shift the methane hydrate (liquid + vapour) equilibrium curve (HLVE) to lower temperature and higher pressure. Our results indicate 1-(2-hydroxyethyl) 3-methylimidazolium chloride is the best among the ILs studied as a thermodynamic hydrate inhibitor. A statistical analysis reveals there is a moderate correlation between electrical conductivity and the efficiency of the IL as a gas hydrate inhibitor. The average enthalpies of methane hydrate dissociation in the presence of these ILs are found to be in the range of (57.0 to 59.1) kJ ⋅ mol−1. There is no significant difference between the dissociation enthalpy of methane hydrate either in the presence or in absence of ILs

  8. Structure and dynamics of H$_2^+$ near the dissociation threshold: a combined experimental and computational investigation

    CERN Document Server

    Beyer, Maximilian

    2016-01-01

    The pulsed-field-ionization zero-kinetic-energy photoelectron spectrum of H$_2$ has been recorded in the vicinity of the dissociative-ionization threshold following three-photon excitation via selected rotational levels of the B $^1\\Sigma_u^+$ ($v=19$) and $\\bar{\\rm H}$ $^1\\Sigma_g^+$ ($v=11$) intermediate states. The spectra consist of transitions to bound levels of the X$^+$ $^2\\Sigma_g^+$ state of H$_2^+$ with $v^+$ in the range 14-19 and $N^+$ in the range 0-9, of the A$^+$ $^2\\Sigma_u^+$ state with $v^+=0$ and $N^+=0-2$, and of shape resonances corresponding to the X$^+\\ (v^+=17,N^+=7)$ and X$^+\\ (v^+=18,N^+=4)$ quasibound levels. Calculations of the level structure of H$_2^+$ have been carried out and the influence of adiabatic, nonadiabatic, relativistic and radiative corrections on the positions of these levels, and in the case of the shape resonances also on their widths, has been investigated. Different methods of calculating the widths and profiles of the shape resonances have been tested for compa...

  9. An investigation into a suitable scintillator for localising neutron capture within a detector

    International Nuclear Information System (INIS)

    Using Monte-Carlo modelling, an investigation into a suitable loaded scintillator for localising neutron capture in a novel neutron survey meter has been undertaken. A comparison of estimated neutron capture location in a scintillator with Geant4 and MCNP simulations was undertaken and a good general agreement between the two models was observed. The interactions of γ emissions from neutron capture in the scintillator are investigated. The results show that the γ emission from neutron capture will not aid neutron capture localisation and will only inhibit it. It is observed that the lithium-loaded scintillator has the lowest neutron capture efficiency when compared with boron and gadolinium scintillators. However, it is the most promising of the detectors investigated in this research for use in a novel neutron survey meter design

  10. 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.

  11. Thermal dissociation of chemisorbed oxygen molecules on Ag(110): an investigation by scanning tunnelling microscopy

    International Nuclear Information System (INIS)

    The thermal dissociation of oxygen molecules on Ag(110) was studied by means of scanning tunnelling microscopy. At temperatures around 170 K a fraction of the molecules dissociate to form pairs of O atoms on the unreconstructed surface. The atoms lie in the trenches between the close-packed Ag rows; the intrapair distance is two lattice constants. The O atoms are very reactive with CO at temperatures as low as 70 K. The preferential orientation of the pairs in the [001] direction contrasts with the finding in a previous study (Hahn J R, Lee H J and Ho W 2000 Phys. Rev. Lett. Vol. 85 1914) that electron-induced dissociation exclusively leads to [110]-oriented pairs. The trajectories of thermal and electron-induced dissociations must therefore be different. In the temperature range of the dissociation, several additional oxygen features occur on the surface. These include unreacted O2 molecules, the first nuclei of the added-row reconstruction, and two unidentified O-induced structures. (author)

  12. Evaluation of the internal temperatures of an 8.6 kDa protein cation exposed to a hot dispenser cathode employed in electron capture dissociation mass spectrometry.

    Science.gov (United States)

    Yim, Yong-Hyeon; Kim, Byungjoo; Ahn, Seonghee; So, Hun-Young; Lee, Sunyoung; Oh, Han Bin

    2006-01-01

    The 'effective' internal temperature of an 8.6 kDa ubiquitin cation was estimated under electron capture dissociation (ECD) conditions, in which a dispenser cathode electron source was mounted just outside an ion cyclotron resonance (ICR) cell, i.e., axially displaced at a distance less than 1 cm from the rear trap plate of the ICR cell. In this ECD configuration, thermal activation of the molecular ions stored in the ICR cell was anticipated since the heated dispenser cathode (T(cathode surface) > 1000 degrees C) emitted a large amount of (both visible and infrared) radiation as well as electrons. An evaluation of the internal temperature of ubiquitin 6+ and 7+ cations was made by comparing our ECD fragmentation patterns with those obtained by McLafferty et al. (J. Am. Chem. Soc. 2002; 124: 6407) as a function of the ion temperature. In McLafferty's configuration, the heating (or thermal activation) effect of their filament source was minimal since the filament was displaced by a distance as far as 70 cm from their ICR cell. A careful comparison reveals that the fragmentation patterns obtained in this work are very similar to those previously measured at T approximately 125 degrees C. In terms of sequence coverage, our ECD configuration provides better results, and in particular without the aid of any other simultaneous activation method, such as thermal heating, infrared multiphoton irradiation, or collisional activation, except for the visible and infrared radiation from the heated cathode. PMID:16715464

  13. 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)

    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

  14. Remarks on CO{sub 2} capture from electric power plants and recommendations for future investigations

    Energy Technology Data Exchange (ETDEWEB)

    Wolsky, A.M. [Argonne National Laboratory, IL (United States)

    1993-12-31

    This paper recommends investigation of several topics that have not yet received sustained attention. Each bears directly on the cost and funding of CO{sub 2} capture and sequestration. The reasons why each topic deserves attention are briefly sketched.

  15. Investigation into optimal CO2 concentration for CO2 capture from aluminium production

    OpenAIRE

    Mathisen, Anette; Sørensen, Henriette; Melaaen, Morten Christian; Müller, Gunn-Iren

    2013-01-01

    Capture of CO2 from aluminum production has been simulated using Aspen Plus and Aspen Hysys. The technology used for aluminum production is the Hall-Héroult and the current cell design necessitates that large amounts of false air is supplied to the cells. This results in a CO2 concentration in the process gas at around 1 vol%, which is considered uneconomical for CO2 capture. Therefore, the aim of this investigation is to evaluate the CO2 capture from aluminum production when the process g...

  16. Numerical Investigation of Hydrate Dissociation Performance in the South China Sea with Different Horizontal Well Configurations

    Directory of Open Access Journals (Sweden)

    Jing-Chun Feng

    2014-07-01

    Full Text Available Based on the available measurement data and literature on the hydrate deposits of the South China Sea, a numerical simulation with a new dual horizontal well system has been carried out. Warm brine stimulation combined with depressurization is employed as the production method. Two horizontal wells were situated in the same horizontal plane and they were placed in the middle of the Hydrate-Bearing Layer (HBL. The warm brine is injected from the left well (LW into the reservoir, and the right well (RW acted as the producer under constant pressure. The simulation results show that the effects of hydrate dissociation rate, gas to water ratio, and energy ratio are all better than the previous work in which the dual horizontal wells are placed in the same vertical plane. In addition, the sensitivity analysis indicates that a higher injection rate can enhance the hydrate dissociation rate and gas production rate, while a lower injection rate gives a more favorable gas to water ratio and energy ratio.

  17. Investigation of Ionization and Dissociation Processes Produced by Electron Impact on Molecules.

    Science.gov (United States)

    Ma, Ce.

    1990-01-01

    Absolute electron impact partial ionization cross sections for Ar and CF_4 were measured by use of a newly built pulsed electron beam time-of-flight apparatus for incident electron energies from thresholds to 500 eV. The apparatus employed consisted of a low energy electron gun, 40 mm diameter ion extraction gold screens, time-of-flight drift tubes, micro-channel plate detectors and fast time to digital electronics. A pulsed electron beam was obtained by pulsing the control grid of the electron gun. Both beam - beam experiments and beam - constant gas target pressure experiments were carried out to determine the absolute partial ionization cross sections for Ar ^{+}, Ar^{2+ }, Ar^{3+} from an argon gas target, and for CF_sp {3}{+}, CF_sp {2}{+}, CF_sp {3}{2+}, CF^ {+}, CF_sp{2} {2+}, F^{+}, C^{+} from a CF _4 gas target. By charge weighted summing of the partial ionization cross sections, the total ionization cross sections of Ar and CF_4 were obtained. The total neutral dissociation cross section for CF_4 was inferred from the total ionization cross section and the total dissociation cross section. Also, a new method for determining absolute total electron scattering cross sections with corrections for forward scattering was developed. The electron beam current was measured as function of gas target pressure and the scattering path length. The total electron scattering cross section obtained from the new model is as much as 6% larger than the cross section derived from the traditional Beer's law for Ar at an incident electron energy of 300 eV. This method is capable of yielding reliable total cross section up to 10 keV. Finally, a study of the secondary electron emission as a function of ejection angle and ejection energy for CO, the doubly differential cross section (DDCS), is presented.

  18. Infrared multiple photon dissociation spectroscopy of ciprofloxacin: Investigation of the protonation site

    Science.gov (United States)

    Bodo, E.; Ciavardini, A.; Giardini, A.; Paladini, A.; Piccirillo, S.; Rondino, F.; Scuderi, D.

    2012-04-01

    The vibrational spectrum of isolated protonated ciprofloxacin was recorded in the range 1100-2000 cm-1 by means of infrared multiple photon dissociation (IRMPD) spectroscopy. The spectrum was obtained by electrospraying a methanol solution of ciprofloxacin in a Paul ion trap, coupled to the tunable IR radiation of a free electron laser. This spectroscopic study has been complemented by quantum chemical calculations at the DFT and MP2 levels of theory to identify the possible structures present under our experimental conditions. Several low-energy isomers with protonation occurring at the piperazinyl amino group and at the carbonyl group are predicted in the energy range 0-84 kJ mol-1. A good agreement between the measured IRMPD spectrum and the calculated absorption spectrum is observed for the isomer protonated at the piperazinyl amino group. This isomer is calculated at MP2 level of theory to lie about 76 kJ/mol above the most stable isomer which is protonated at the quinone carbonyl group. This discrepancy can be rationalized by assuming that the protonation at the piperazinyl amino group, typical of the zwitterionic form that is found in protic solvents, is retained in the ESI process. The vibrational bands observed in the IRMPD spectrum are assigned to normal modes of the isomer protonated at the piperazinyl amino group, with deviations of less than 20 cm-1 between measured and calculated frequencies.

  19. Infrared multiple photon dissociation spectroscopy of ciprofloxacin: Investigation of the protonation site

    International Nuclear Information System (INIS)

    Highlights: ► IRMPD spectroscopy of protonated ciprofloxacin electrosprayed from methanol solution. ► Quantum chemical calculations to identify the possible isomers differing in the protonation site. ► Bands are assigned to the isomer protonated. ► Bands are assigned to the isomer protonated at the piperazinyl amino group. - Abstract: The vibrational spectrum of isolated protonated ciprofloxacin was recorded in the range 1100–2000 cm−1 by means of infrared multiple photon dissociation (IRMPD) spectroscopy. The spectrum was obtained by electrospraying a methanol solution of ciprofloxacin in a Paul ion trap, coupled to the tunable IR radiation of a free electron laser. This spectroscopic study has been complemented by quantum chemical calculations at the DFT and MP2 levels of theory to identify the possible structures present under our experimental conditions. Several low-energy isomers with protonation occurring at the piperazinyl amino group and at the carbonyl group are predicted in the energy range 0–84 kJ mol−1. A good agreement between the measured IRMPD spectrum and the calculated absorption spectrum is observed for the isomer protonated at the piperazinyl amino group. This isomer is calculated at MP2 level of theory to lie about 76 kJ/mol above the most stable isomer which is protonated at the quinone carbonyl group. This discrepancy can be rationalized by assuming that the protonation at the piperazinyl amino group, typical of the zwitterionic form that is found in protic solvents, is retained in the ESI process. The vibrational bands observed in the IRMPD spectrum are assigned to normal modes of the isomer protonated at the piperazinyl amino group, with deviations of less than 20 cm−1 between measured and calculated frequencies.

  20. Infrared multiple photon dissociation spectroscopy of ciprofloxacin: Investigation of the protonation site

    Energy Technology Data Exchange (ETDEWEB)

    Bodo, E. [Dip. Di Chimica, Universita di Roma ' La Sapienza' , p.le A. Moro 5, 00185 Rome (Italy); Ciavardini, A. [Dip. di Chimica e Tecnologie del Farmaco, Universita di Roma ' ' La Sapienza' ' , p.le A. Moro 5, 00185 Rome (Italy); Dip. di Scienze e Tecnologie Chimiche, Universita di Roma ' ' Tor Vergata' ' , via della Ricerca Scientifica, 00133 Rome (Italy); Giardini, A.; Paladini, A. [CNR - IMIP, Tito Scalo (PZ) (Italy); Piccirillo, S., E-mail: picciril@uniroma2.it [Dip. di Scienze e Tecnologie Chimiche, Universita di Roma ' ' Tor Vergata' ' , via della Ricerca Scientifica, 00133 Rome (Italy); Rondino, F. [ENEA, C.R. Casaccia, (UTT-MAT), Via Anguillarese, 301, 00123 Rome (Italy); Scuderi, D. [Laboratoire de Chimie Physique, Universite Paris Sud 11, UMR 8000, Orsay (France)

    2012-04-04

    Highlights: Black-Right-Pointing-Pointer IRMPD spectroscopy of protonated ciprofloxacin electrosprayed from methanol solution. Black-Right-Pointing-Pointer Quantum chemical calculations to identify the possible isomers differing in the protonation site. Black-Right-Pointing-Pointer Bands are assigned to the isomer protonated. Black-Right-Pointing-Pointer Bands are assigned to the isomer protonated at the piperazinyl amino group. - Abstract: The vibrational spectrum of isolated protonated ciprofloxacin was recorded in the range 1100-2000 cm{sup -1} by means of infrared multiple photon dissociation (IRMPD) spectroscopy. The spectrum was obtained by electrospraying a methanol solution of ciprofloxacin in a Paul ion trap, coupled to the tunable IR radiation of a free electron laser. This spectroscopic study has been complemented by quantum chemical calculations at the DFT and MP2 levels of theory to identify the possible structures present under our experimental conditions. Several low-energy isomers with protonation occurring at the piperazinyl amino group and at the carbonyl group are predicted in the energy range 0-84 kJ mol{sup -1}. A good agreement between the measured IRMPD spectrum and the calculated absorption spectrum is observed for the isomer protonated at the piperazinyl amino group. This isomer is calculated at MP2 level of theory to lie about 76 kJ/mol above the most stable isomer which is protonated at the quinone carbonyl group. This discrepancy can be rationalized by assuming that the protonation at the piperazinyl amino group, typical of the zwitterionic form that is found in protic solvents, is retained in the ESI process. The vibrational bands observed in the IRMPD spectrum are assigned to normal modes of the isomer protonated at the piperazinyl amino group, with deviations of less than 20 cm{sup -1} between measured and calculated frequencies.

  1. Investigating carbonate formation in urban soils as a method for capture and storage of atmospheric carbon.

    Science.gov (United States)

    Washbourne, C-L; Renforth, P; Manning, D A C

    2012-08-01

    This paper investigates the potential for engineered urban soils to capture and store atmospheric carbon (C). Calcium (Ca) and magnesium (Mg) bearing waste silicate minerals within the soil environment can capture and store atmospheric C through the process of weathering and secondary carbonate mineral precipitation. Anthropogenic soils, known to contain substantial quantities of Ca and Mg-rich minerals derived from demolition activity (particularly cement and concrete), were systematically sampled at the surface across a 10 ha brownfield site, Science Central, located in the urban centre of Newcastle upon Tyne, U.K. Subsequent analysis yielded average carbonate contents of 21.8±4.7% wt CaCO(3). Isotopic analysis demonstrated δ(18)O values between -9.4‰ and -13.3‰ and δ(13)C values between -7.4‰ and -13.6‰ (relative to Pee Dee Belemnite), suggesting that up to 39.4±8.8% of the carbonate C has been captured from the atmosphere through hydroxylation of dissolved CO(2) in high pH solutions. The remaining carbonate C is derived from lithogenic sources. 37.4 kg of atmospheric CO(2) has already been captured and stored as carbonate per Mg of soil across the site, representing a carbon dioxide (CO(2)) removal rate of 12.5 kg CO(2) Mg(-1) yr(-1). There is the potential for capture and storage of a further 27.3 kg CO(2) Mg(-1) in residual reactive materials, which may be exploited through increased residence time (additional in situ weathering). Overall, the Science Central site has the potential to capture and store a total of 64,800 Mg CO(2) as carbonate minerals. This study illustrates the potential for managing urban soils as tools of C capture and storage, an important ecosystem service, and demonstrates the importance of studying C storage in engineering urban anthropogenic soils. PMID:22683756

  2. Investigating carbonate formation in urban soils as a method for capture and storage of atmospheric carbon

    International Nuclear Information System (INIS)

    This paper investigates the potential for engineered urban soils to capture and store atmospheric carbon (C). Calcium (Ca) and magnesium (Mg) bearing waste silicate minerals within the soil environment can capture and store atmospheric C through the process of weathering and secondary carbonate mineral precipitation. Anthropogenic soils, known to contain substantial quantities of Ca and Mg-rich minerals derived from demolition activity (particularly cement and concrete), were systematically sampled at the surface across a 10 ha brownfield site, Science Central, located in the urban centre of Newcastle upon Tyne, U.K. Subsequent analysis yielded average carbonate contents of 21.8 ± 4.7% wt CaCO3. Isotopic analysis demonstrated δ18O values between − 9.4‰ and − 13.3‰ and δ13C values between − 7.4‰ and − 13.6‰ (relative to Pee Dee Belemnite), suggesting that up to 39.4 ± 8.8% of the carbonate C has been captured from the atmosphere through hydroxylation of dissolved CO2 in high pH solutions. The remaining carbonate C is derived from lithogenic sources. 37.4 kg of atmospheric CO2 has already been captured and stored as carbonate per Mg of soil across the site, representing a carbon dioxide (CO2) removal rate of 12.5 kgCO2 Mg−1 yr−1. There is the potential for capture and storage of a further 27.3 kgCO2 Mg−1 in residual reactive materials, which may be exploited through increased residence time (additional in situ weathering). Overall, the Science Central site has the potential to capture and store a total of 64,800 Mg CO2 as carbonate minerals. This study illustrates the potential for managing urban soils as tools of C capture and storage, an important ecosystem service, and demonstrates the importance of studying C storage in engineering urban anthropogenic soils. Highlights: ► Urban soils potentially capture 12.5 kgCO2 Mg−1 yr−1 (value £51,843–£77,765 ha−1). ► Formation of carbonate may be significant and exploitable storage

  3. 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.

  4. Investigation of the Statistical Properties of Stable Eu Nuclei using Neutron-Capture Reactions

    International Nuclear Information System (INIS)

    Neutron capture for incident neutron energies 151,153Eu targets. The highly efficient DANCE (Detector for Advanced Neutron Capture Experiments) array coupled with the intense neutron beam at Los Alamos Neutron Science Center is used for the experiment. Stable Eu isotopes mass separated and electroplated on Be backings were used. Properties of well-resolved, strong resonances in two Eu nuclei are examined. The parameters for most of these resonances are known. Detailed multiplicity information for each resonance is obtained employing the high granularity of the DANCE array. The radiative decay cascades corresponding to each resonance are obtained in the experiment. The measurements are compared to simulation of these cascades which calculated with various models for the radiative strength function. Comparison between the experimental data and simulation provides an opportunity to investigate the average quantities

  5. Voltammetric investigation of the dissociative electron transfer to polychloromethanes at catalytic and non-catalytic electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Isse, Abdirisak Ahmed; Sandona, Giancarlo; Durante, Christian [Dipartimento di Scienze Chimiche, Universita di Padova, Via Marzolo 1, 35131 Padova (Italy); Gennaro, Armando [Dipartimento di Scienze Chimiche, Universita di Padova, Via Marzolo 1, 35131 Padova (Italy)], E-mail: armando.gennaro@unipd.it

    2009-04-30

    The electrochemical behavior of CCl{sub 4}, CHCl{sub 3} and CH{sub 2}Cl{sub 2} has been investigated by cyclic voltammetry at glassy carbon and silver electrodes in DMF + 0.1 M Et{sub 4}NClO{sub 4} in the absence and presence of a good proton donor. At both electrodes, each compound exhibits a series of reduction peaks which represent sequential hydrodechlorination steps up to methane. The nature of the electrode material and the proton availability of the medium affect drastically the voltammetric pattern of the compounds. Silver exhibits extraordinary electrocatalytic properties toward the reduction process, with positive shifts of the peak potentials of about 0.57-0.95 V as compared to glassy carbon. Reduction of any polychloromethane, CH{sub n}Cl{sub (4-n)} (n = 0-2), yields the carbanion CH{sub n}Cl{sub (3-n)}{sup -} which partitions into two reaction channels: (i) protonation and (ii) Cl{sup -} elimination to give a carbene :CH{sub n}Cl{sub (2-n)}. If a strong proton donor is added into the solution, sequential hydrodechlorination becomes the principal reaction route at both electrodes. When, instead, purposely added acid is not present in solution, both reaction pathways ought to be considered. In these conditions, when possible, self-protonation reactions play an important role in the overall reduction process.

  6. Iron-boron pair dissociation in silicon under strong illumination

    Directory of Open Access Journals (Sweden)

    Xiaodong Zhu

    2013-08-01

    Full Text Available The dissociation of iron-boron pairs (FeB in Czochralski silicon under strong illumination was investigated. It is found that the dissociation process shows a double exponential dependence on time. The first fast process is suggested to be caused by a positive Fe in FeB capturing two electrons and diffusion triggered by the electron-phonon interactions, while the second slow one would involve the capturing of one electron followed by temperature dependent dissociation with an activation energy of (0.21 ± 0.03 eV. The results are important for understanding and controlling the behavior of FeB in concentrator solar cells.

  7. Investigation of magnevist pharmacokinetics for calculation of absorbed dose at neutron-capture therapy

    International Nuclear Information System (INIS)

    Full text: The neutron-capture therapy with use of gadolinium-containing pharmacological preparations is one of perspective and not enough investigated directions of application of neutron irradiation in medicine. At definition of the absorbed dose of neutron-capture therapy one of important questions is definition of concentration gadolinium and pharmacokinetics in irradiated tumour. In the given study has been investigated pharmacokinetics of gadolinium-containing preparation 'Magnevist' at intratumoral injection in inoculated tumours of sarcoma C180 at mice. For 'Magnevist' detection its property of radioopacity has been used. In experiments to mice with inoculated tumours C180 the various doses of 'Magnevist' (0.1, 0.2, 0.3 and 0.4 ml) were injected into tumour centre. X-ray images were made before 'Magnevist' injection (control) and after preparation injection every 5 minutes within one hour. It has been shown that at dose 0.1 ml 'Magnevist' eliminated from tumour within 10 minutes. At higher doses of preparation more slow elimination of 'Magnevist' from injection site was observed. Obtained results allow with sufficient accuracy to calculate the time of presence of optimum concentration of 'Magnevist' in tumour at intratumoral injection. It in turn gives the chance to calculate precisely the absorbed dose at irradiation by beam of epi-thermal neutrons. (author)

  8. Investigation of possibilities of application of neutron capture gamma-ray spectrometry for cement manufactures control

    International Nuclear Information System (INIS)

    Full text: Creation of system of Automatic Management of Technological Processes in cement industry still remains an actual problem, solution of which leads to increase in volume and improvement in the quality of the ready product, and also gives opportunity to effective use of electro energy and raw material resources. In preparation of cement acute stands the question of realization of operative control of the content of main technologically important elements: like Ca, Mg, Fe, Si and Al in the initial raw material and different content must be determined on the technological stream. Among existing analytical methods, nuclear physics method based on prompt gamma radiation of neutron capture spectrometry is one of the better possibilities/1,2/. In this work, results of investigation of possibilities of express determination of technological important elements: Ca, Mg, Fe, Si and Al in the initial raw material by the method of neutron capture prompt gamma - ray spectrometry. Laboratory model of low power radionuclide (252Cf) - source of neutrons with the yield of 5x106 neutron/sec. Measuring equipment consists of semiconductor Ge (Li) - detector with volume of sensitive crystal, 40 sm3 and energy resolution of 4 keV on the line of 60Co with the energy of 1333 keV and multichannel pulse analyzers AI-1024-95. Possibility of express determination of concentration of technologically important elements in the initial raw material of Kyzylkum by means of using neutron capture gamma radiation spectrometry with parameters meeting production requirements of cement industry of Uzbekistan

  9. An investigation of carbon dioxide capture by chitin acetate/DMSO binary system.

    Science.gov (United States)

    Eftaiha, Ala'a F; Alsoubani, Fatima; Assaf, Khaleel I; Troll, Carsten; Rieger, Bernhard; Khaled, Aseel H; Qaroush, Abdussalam K

    2016-11-01

    Chitin is considered to be the second most abundant naturally-occurring polysaccharide. Also, dimethyl sulfoxide (DMSO) is the second highest dielectric constant polar solvent after water. Despite the low solubility of chitin in common organic solvents, and due to its high nitrogen content, it may serve as a potential scrubbing agent "wet scrubbing" for carbon dioxide (CO2) capturing as an alternative to monoethanolamine "renewables for renewables approach". Briefly, a detailed investigation for the utilization of low molecular weight, chitin-acetate (CA) in DMSO for the capturing of CO2 is reported. As carbonation process takes place, the formation of ionic alkylcarbonate was confirmed throughout spectroscopic and computational studies. Supramolecular chemisorption was proven throughout (1)H Nuclear Magnetic Resonance ((1)H NMR) together with the absence of sorption of CO2 by the monomeric repeating unit, glucosamine hydrochloride. Further, Density Functional Theory (DFT) calculations supported the formation of the CA/CO2 adduct through a newly formed supramolecular ionic interaction and hydrogen bonding along the oligosaccharide backbone between the neighboring ammonium ion and hydroxyl functional groups. The sorption capacity was measured volumetrically within an in situ Attenuated Total Reflectance-Fourier Transform Infrared coupled (in situ ATR-FTIR) autoclave at 25.0°C, and 4.0bar CO2, with a maximum sorption capacity of 3.63 [Formula: see text] /gsorbent at 10.0% (w/v). PMID:27516261

  10. Trauma, Posttraumatic Stress and Dissociation Among Swedish Adolescents : Evaluation of Questionnaires

    OpenAIRE

    Nilsson, Doris

    2007-01-01

    The main aim of this thesis has been to investigate trauma and dissociation among Swedish adolescents and to evaluate the psychometric properties such as reliability and various kinds of validity of three screening instruments for assessment of dissociation and other symptoms of post traumatic stress. The three instruments in question have been Dis-Q-Sweden, A-DES and TSCC, the symptoms measured by these instruments are neither easy to capture nor easy for the adolescent to talk about. Theref...

  11. Adsorption and dissociation of H2O on the (001) surface of uranium mononitride: energetics and mechanism from first-principles investigation.

    Science.gov (United States)

    Bo, Tao; Lan, Jian-Hui; Zhang, Yu-Juan; Zhao, Yao-Lin; He, Chao-Hui; Chai, Zhi-Fang; Shi, Wei-Qun

    2016-05-21

    The interfacial interaction of uranium mononitride (UN) with water from the environment unavoidably leads to corrosion of nuclear fuels, which affects a lot of processes in the nuclear fuel cycle. In this work, the microscopic adsorption behaviors of water on the UN(001) surface as well as water dissociation and accompanying H2 formation mechanisms have been investigated on the basis of DFT+U calculations and ab initio atomistic thermodynamics. For adsorption of one H2O monomer, the predicted adsorption energies are -0.88, -2.07, and -2.07 eV for the most stable molecular, partially dissociative, and completely dissociative adsorption, respectively. According to our calculations, a water molecule dissociates into OH and H species via three pathways with small energy barriers of 0.78, 0.72, and 0.85 eV, respectively. With the aid of the neighboring H atom, H2 formation through the reaction of H* + OH* can easily occur via two pathways with energy barriers of 0.61 and 0.36 eV, respectively. The molecular adsorption of water shows a slight coverage dependence on the surface while this dependence becomes obvious for partially dissociative adsorption as the water coverage increases from 1/4 to 1 ML. In addition, based on the "ab initio atomistic thermodynamic" simulations, increasing H2O partial pressure will enhance the stability of the adsorbed system and water coverage, while increasing temperature will decrease the H2O coverage. We found that the UN(001) surface reacts easily with H2O at room temperature, leading to dissolution and corrosion of the UN fuel materials. PMID:27118421

  12. The micellization and dissociation transitions of thermo-, pH- and sugar-sensitive block copolymer investigated by laser light scattering

    OpenAIRE

    Tang, Y. C.; Wu, J. H.; J. X. Duan

    2012-01-01

    A triple-stimuli responsive polymer, poly(3-acrylamidophenylboronic acid)-b-poly(N-isopropylacrylamide) (PAAPBA-b-PNIPAM), has been synthesized by reversible addition-fragmentation chain transfer polymerization. Temperature, pH, and fructose induced micellization and dissociation transition of block copolymer was investigated by a combination of static and dynamic laser light scattering. PAAPBA-b-PNIPAM copolymer self-assembles into micelles with PAAPBA block as core and PNIPAM as shell in lo...

  13. Fragmentation dynamics of CO23+ investigated by multiple electron capture in collisions with slow highly charged ions

    CERN Document Server

    Neumann, N; Schmidt, L Ph H; Titze, J; Jahnke, T; Czasch, A; Schöffler, M S; Kreidi, K; Jagutzki, O; Schmidt-Böcking, H; Dörner, R

    2010-01-01

    Fragmentation of highly charged molecular ions or clusters consisting of more than two atoms can proceed in an onestep synchronous manner where all bonds break simultaneously or sequentially by emitting one ion after the other. We separated these decay channels for the fragmentation of CO23+ ions by measuring the momenta of the ionic fragments. We show that the total energy deposited in the molecular ion is a control parameter which switches between three distinct fragmentation pathways: the sequential fragmentation in which the emission of an O+ ion leaves a rotating CO2+ ion behind that fragments after a time delay, the Coulomb explosion and an in-between fragmentation - the asynchronous dissociation. These mechanisms are directly distinguishable in Dalitz plots and Newton diagrams of the fragment momenta. The CO23+ ions are produced by multiple electron capture in collisions with 3.2 keV/u Ar8+ ions.

  14. Ab Initio Investigation of O-H Dissociation from the Al-OH2 Complex Using Molecular Dynamics and Neural Network Fitting.

    Science.gov (United States)

    Ho, Thi H; Pham-Tran, Nguyen-Nguyen; Kawazoe, Yoshiyuki; Le, Hung M

    2016-01-28

    The dissociation dynamics of the O-H bond in Al-OH2 is investigated on an approximated ab initio potential energy surface (PES). By adopting a dynamic sampling method, we obtain a database of 92 834 configurations. The potential energy for each point is calculated using MP2/6-311G (3df, 2p) calculations; then, a 60-neuron feed-forward neural network is utilized to fit the data to construct an analytic PES. The root-mean-square error (rmse) for the training set is reported as 0.0036 eV, while the rmse for the independent testing set is 0.0034 eV. Such excellent fitting accuracy indeed confirms the reliability of the constructed PES. Subsequently, quasi-classical molecular dynamics (MD) trajectories are performed on the constructed PES at various levels of vibrational excitation in the range of 1.03 to 2.23 eV to investigate the probability of O-H bond dissociation. The results indicate a linear relationship between reaction probability and internal energy, from which we can determine the minimum activation internal energy required for the dissociation as 0.62 eV. Moreover, the O-H bond rupture is shown to be highly correlated with the formation of Al-O bond. PMID:26741404

  15. Investigation of current status in Europe and USA on boron neutron capture therapy

    International Nuclear Information System (INIS)

    This report describes on the spot investigation results of current status of medical irradiation in Europe and USA at Feb. 1999. In HFR (Netherlands), the phase 1 study with the Joint Research Centre (JRC) of the EU had been already finished in those days, at the same time, an improvement of medical irradiation field of VTT(Finland) had been finishing and then clinical trial research had been about to start. On the other hand, phase 1 studies by two groups of BNL (Brook heaven National Laboratory) and MIT (Nuclear Engineering of Massachusetts Institute of Technology) in US were now in almost final stage, and they would start on phase 2 study. Either reactors of MIT and BNL were in modification to increase neutron flux, especially that employing fission converter into the irradiation facility and installation of irradiation room were carrying out in the former. In Europe and USA, the accelerator-based BNCT planes are now in progress vigorously, and will have reality. A reform of dynamitron accelerator at University of Birmingham was progressed, and the clinical treatment would be started from September 2000. The accelerator group at MIT has a small type of tandem accelerator, and they were performing basic experiment for BNCS (Boron Neutron Capture Synovectomy) with this accelerator. The concept design for an accelerator and a moderator had been finished at Lawrence Berkeley National Laboratory and University of Berkeley. (author)

  16. Investigation of current status in Europe and USA on boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-11-01

    This report describes on the spot investigation results of current status of medical irradiation in Europe and USA at Feb. 1999. In HFR (Netherlands), the phase 1 study with the Joint Research Centre (JRC) of the EU had been already finished in those days, at the same time, an improvement of medical irradiation field of VTT(Finland) had been finishing and then clinical trial research had been about to start. On the other hand, phase 1 studies by two groups of BNL (Brook heaven National Laboratory) and MIT (Nuclear Engineering of Massachusetts Institute of Technology) in US were now in almost final stage, and they would start on phase 2 study. Either reactors of MIT and BNL were in modification to increase neutron flux, especially that employing fission converter into the irradiation facility and installation of irradiation room were carrying out in the former. In Europe and USA, the accelerator-based BNCT planes are now in progress vigorously, and will have reality. A reform of dynamitron accelerator at University of Birmingham was progressed, and the clinical treatment would be started from September 2000. The accelerator group at MIT has a small type of tandem accelerator, and they were performing basic experiment for BNCS (Boron Neutron Capture Synovectomy) with this accelerator. The concept design for an accelerator and a moderator had been finished at Lawrence Berkeley National Laboratory and University of Berkeley. (author)

  17. Is game immersion just another form of selective attention? An empirical investigation of real world dissociation in computer game immersion

    OpenAIRE

    Jennett, C. I.

    2010-01-01

    When your daughter is playing video-games and you call her to dinner but she fails to respond, do you assume she heard you and ignored you? Everyday descriptions of game immersion suggest that the real world dissociation experienced by gamers could be an extreme form of selective attention. If this were the case, this would mean that your daughter really did not hear you call, due to the complexity of the game environment and a lack of available cognitive resources. This thesis...

  18. Investigation of thermal neutron capture in 23Na, 138Ba, 140Ce and 142Ce

    International Nuclear Information System (INIS)

    A measurement of the angular correlation of γ-rays emitted in the capture of thermal neutrons in 23Na has been used to determine the multipole mixing ratio delta for seventeen transitions in 24Na, of which seven are primary transitions. For these primary transitions also the capture state spin admixture α has been derived. The neutron capture reaction proceeds predominantly through the Jsup(π)=1+ channel, as expected from previous cross-section measurements. A measurement of the circular polarization of γ-rays resulting from the capture of polarized thermal neutrons in 138Ba, 140Ce and 142Ce has yielded spin assignments for p-states in the final nuclei. Excitation energies and reaction Q-values have been obtained from the analysis of singles spectra taken with unpolarized neutrons. (Auth.)

  19. Multiphoton dissociation of polyatomic molecules

    International Nuclear Information System (INIS)

    The dynamics of infrared multiphoton excitation and dissociation of SF6 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 SF6, the pulse duration of the CO2 laser and the frequency in both one and two laser experiments. Translational energy distributions of the SF5 dissociation product measured by time of flight and angular distributions and the dissociation lifetime of excited SF6 as inferred from the observation of secondary dissociation of SF5 into SF4 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

  20. Investigation of Peculiarities of a High-Voltage Pulsing Corona Discharge in Carbonic Gas and an Feature Using of Such Discharge for CO2 Dissociation

    International Nuclear Information System (INIS)

    On laboratory stand of plasmochemical reactor the feature of CO2 dissociation with the purpose of CO production in high-voltage pulsing corona discharge is investigated at a voltage up to 120 kV, a pulse length of a current 0,5 μs a repetition rate up to 100 Hz. Peculiarities of volt-ampere characteristics of such discharge are studied at different pressures of air and carbonic gas in the discharge chamber and construction of an interior electrode. It is established that in conditions of the carried out experiments a maximum efficiency of CO accretion does not exceed 3,5%

  1. Investigation of CO2 capture mechanisms of liquid-like nanoparticle organic hybrid materials via structural characterization

    KAUST Repository

    Park, Youngjune

    2011-01-01

    Nanoparticle organic hybrid materials (NOHMs) have been recently developed that comprise an oligomeric or polymeric canopy tethered to surface-modified nanoparticles via ionic or covalent bonds. It has already been shown that the tunable nature of the grafted polymeric canopy allows for enhanced CO 2 capture capacity and selectivity via the enthalpic intermolecular interactions between CO2 and the task-specific functional groups, such as amines. Interestingly, for the same amount of CO2 loading NOHMs have also exhibited significantly different swelling behavior compared to that of the corresponding polymers, indicating a potential structural effect during CO2 capture. If the frustrated canopy species favor spontaneous ordering due to steric and/or entropic effects, the inorganic cores of NOHMs could be organized into unusual structural arrangements. Likewise, the introduction of small gaseous molecules such as CO2 could reduce the free energy of the frustrated canopy. This entropic effect, the result of unique structural nature, could allow NOHMs to capture CO2 more effectively. In order to isolate the entropic effect, NOHMs were synthesized without the task-specific functional groups. The relationship between their structural conformation and the underlying mechanisms for the CO2 absorption behavior were investigated by employing NMR and ATR FT-IR spectroscopies. The results provide fundamental information needed for evaluating and developing novel liquid-like CO2 capture materials and give useful insights for designing and synthesizing NOHMs for more effective CO2 capture. © the Owner Societies 2011.

  2. Investigation of new polymeric membranes with controlled architecture for CO2 capture

    OpenAIRE

    Rahman, Mohammad Mashukur

    2011-01-01

    The capture of CO2 is of high interest in a society concerned by climate change and consequently by greenhouse gas emissions. If the amine absorption or hot potassium scrubbing are widely used, several membrane processes are also employed. Many studies are realized to develop new polymers in order to increase the selectivity and permeability of membranes. Polyether based copolymers are particularly studied because of the high flexibility of the polyether chain which enables good gas diffusion...

  3. Investigation of New Polymeric Membranes with Controlled Architecture for CO2 Capture

    OpenAIRE

    Prache, Marie Odile

    2012-01-01

    The capture of CO2 is of high interest in a society concerned by climate change and consequently by greenhouse gas emissions. If the amine absorption or hot potassium scrubbing are widely used, several membrane processes are also employed. Many studies are realized to develop new polymers in order to increase the selectivity and permeability of membranes. Polyether based copolymers are particularly studied because of the high flexibility of the polyether chain which enables good gas diffusion...

  4. Investigations of 1-(4-propylamino-3-ethyl imidazolium tetrafluoroborate ionic liquid capturing CO2

    Directory of Open Access Journals (Sweden)

    Yang Lijuan

    2013-01-01

    Full Text Available 1-(4-propylamino-3-ethyl imidazolium ([Paeim]+ Tetrafluoroborate([BF4]- Ionic liquid (IL, capturing CO2, was explored systematically at B3LYP/6-311++G** and mp2/6-311++G** level. The stable geometries of ILs and capture products were optimized, the energies of these geometries were obtained and corrected by Zero-point-vibration-energy and basis set superposition error correction. The results show that the interactions between [Paeim]+and [BF4]-are mainly displayed as hydrogen bonds, but the interaction energies exceeds -328 kJ/mol. Further analysis found that the interactions are reinforced by charge dispersion and charge redistribution of ion-pair, and that electrostatic attraction contributes much to the interaction energies. This IL system capturing CO2belongs to the class of physical sorption with 1:1 molar absorption ratio, the absorption energy is nearly -18kJ/moland thus this IL may have low energy consumption when regenerated from IL-CO2.

  5. Investigation of 186Re via radiative thermal-neutron capture on 185Re

    Science.gov (United States)

    Matters, D. A.; Lerch, A. G.; Hurst, A. M.; Szentmiklósi, L.; Carroll, J. J.; Detwiler, B.; Révay, Zs.; McClory, J. W.; McHale, S. R.; Firestone, R. B.; Sleaford, B. W.; Krtička, M.; Belgya, T.

    2016-05-01

    Partial γ -ray production cross sections and the total radiative thermal-neutron capture cross section for the 185Re(n ,γ ) 186Re reaction were measured using the Prompt Gamma Activation Analysis facility at the Budapest Research Reactor with an enriched 185Re target. The 186Re cross sections were standardized using well-known 35Cl(n ,γ )36Cl cross sections from irradiation of a stoichiometric natReCl3 target. The resulting cross sections for transitions feeding the 186Re ground state from low-lying levels below a cutoff energy of Ec=746 keV were combined with a modeled probability of ground-state feeding from levels above Ec to arrive at a total cross section of σ0=111 (6 ) b for radiative thermal-neutron capture on 185Re. A comparison of modeled discrete-level populations with measured transition intensities led to proposed revisions for seven tentative spin-parity assignments in the adopted level scheme for 186Re. Additionally, 102 primary γ rays were measured, including 50 previously unknown. A neutron-separation energy of Sn=6179.59 (5 ) keV was determined from a global least-squares fit of the measured γ -ray energies to the known 186Re decay scheme. The total capture cross section and separation energy results are comparable to earlier measurements of these values.

  6. The micellization and dissociation transitions of thermo-, pH- and sugar-sensitive block copolymer investigated by laser light scattering

    Directory of Open Access Journals (Sweden)

    Y. C. Tang

    2012-08-01

    Full Text Available A triple-stimuli responsive polymer, poly(3-acrylamidophenylboronic acid-b-poly(N-isopropylacrylamide (PAAPBA-b-PNIPAM, has been synthesized by reversible addition-fragmentation chain transfer polymerization. Temperature, pH, and fructose induced micellization and dissociation transition of block copolymer was investigated by a combination of static and dynamic laser light scattering. PAAPBA-b-PNIPAM copolymer self-assembles into micelles with PAAPBA block as core and PNIPAM as shell in lower pH aqueous solution at room temperature. Increasing the temperature causes the micelle to shrink due to the dehydration of PNIPAM segments at pH 6.2. After the elevation of solution pH from 6.2 to 10.0, the increase in the hydrophilicity of PAAPBA block leads to an expulsion of unimers from micelles. In addition, the fructose addition further enhances the dissociation of micelles. Our experiments demonstrate that the micelle to unimer transition process proceeds via the step-by-step sequential expulsion of individual chains.

  7. First-principles investigation of methanethiol adsorption and dissociation mechanisms on the high-Miller-index vicinal surface Cu(4 1 0)

    Science.gov (United States)

    Raouafi, Faycal; Seydou, Mahamadou; Lassoued, Karima; Taleb, Abdelhafed; Diawara, Boubakar

    2016-05-01

    In this work, we present detailed investigations of methanethiol adsorption on a Cu(4 1 0) surface within the framework of the self-consistent first-principles calculations as implemented in the Vienna ab initio simulation package (VASP). In particular, the adsorption sites, the surface coverage rate and electronic properties have been determined and compared to experimental values. The results indicate that the favorable adsorption site in the case of low coverage rate is a bridge on the step followed by the hollow site on the terrace. The adsorption significantly affects the outermost layer of the surface mainly for a higher coverage rate in a (2  ×  2) supercell. The nature of the chemisorption process on the surface is analyzed by means of the density of states which, combined with charge density difference and atomic charge calculations, confirms the ionic character of the S-Cu bond. The specific effect of the presence of steps is highlighted by comparing the adsorption on the (1 0 0) terrace to the adsorption on the extended Cu(1 0 0) surface. Compared to the flat Cu(1 0 0), it is found here that while the stability is almost the same at p(2  ×  2) coverage, the CH3S/Cu(4 1 0) becomes more stable than CH3S/Cu(1 0 0) at c(2  ×  2) coverage with 0.30 eV per molecule. The mechanism of methanethiol dissociation is explored by the nudged elastic band method and demonstrates that the most favorable path is dissociation followed by migration of hydrogen from the step to its most stable position (hollow on the terrace) with energy barriers less than 0.5 eV.

  8. Investigation of the P-odd asymmetry in the resonance scattering of neutron capture gamma-rays

    International Nuclear Information System (INIS)

    The PCN-Asymmetry of the resonance scattering of circularly polarized neutron capture gamma-rays was investigated for the following nuclei as scatterers: 112Cd, 118Sn, 139La, 141Pr, 142Nd, 205Tl and 208Pb. The experiments were carried out on the polarized neutron beam of the Institut Laue Langevin's High Flux Reactor. For six nuclei-scatterer combinations limits on the value of the PNC-asymmetry of the order 10-4 to 10-3 were obtained. For 205Tl a PNC-asymmetry of a=(+ 4.8 ± 1.5).10-5 was observed

  9. A Mechanistic Investigation of the Enhanced Cleavage at Histidine in the Gas-Phase Dissociation of Protonated Peptides

    OpenAIRE

    Tsaprailis, George; Nair, Hari; Zhong, Wenqing; Kuppannan, Krishnamoorthy; Futrell, Jean H.; Wysocki, Vicki H

    2004-01-01

    Enhanced gas-phase cleavage of peptides adjacent to histidine was investigated. The peptides examined were angiotensins III (RVYIHPF) and IV (VYIHPF) as well as synthetic peptide analogs with altered key residues ((R)VYI-X-Z-F; X=F or H and Z=A, P or Sar) or a fixed charge Φ3P+CH2C(O)-VYIHPF. While all singly protonated peptide ions containing both histidine and arginine fragment non-selectively, the doubly protonated peptide ions with arginine and histidine, and the singly protonated peptide...

  10. Gas-phase thermal dissociation of uranium hexafluoride: Investigation by the technique of laser-powered homogeneous pyrolysis

    International Nuclear Information System (INIS)

    In the gas-phase, uranium hexafluoride decomposes thermally in a quasi-unimolecular reaction to yield uranium pentafluoride and atomic fluorine. We have investigated this reaction using the relatively new technique of laser-powered homogeneous pyrolysis, in which a megawatt infrared laser is used to generate short pulses of high gas temperatures under strictly homogeneous conditions. In our investigation, SiF4 is used as the sensitizer to absorb energy from a pulsed CO2 laser and to transfer this energy by collisions with the reactant gas. Ethyl chloride is used as an external standard ''thermometer'' gas to permit estimation of the unimolecular reaction rate constants by a relative rate approach. When UF6 is the reactant, CF3Cl is used as reagent to trap atomic fluorine reaction product, forming CF4 as a stable indicator which is easily detected by infrared spectroscopy. Using these techniques, we estimate the UF6 unimolecular reaction rate constant near the high-pressure limit. In the Appendix, we describe a computer program, written for the IBM PC, which predicts unimolecular rate constants based on the Rice-Ramsperger-Kassel theory. Parameterization of the theoretical model is discussed, and recommendations are made for ''appropriate'' input parameters for use in predicting the gas-phase unimolecular reaction rate for UF6 as a function of temperature and gas composition and total pressure. 85 refs., 17 figs., 14 tabs

  11. Gas-phase thermal dissociation of uranium hexafluoride: Investigation by the technique of laser-powered homogeneous pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, W.D.; McCulla, W.H.; Trowbridge, L.D.

    1987-04-01

    In the gas-phase, uranium hexafluoride decomposes thermally in a quasi-unimolecular reaction to yield uranium pentafluoride and atomic fluorine. We have investigated this reaction using the relatively new technique of laser-powered homogeneous pyrolysis, in which a megawatt infrared laser is used to generate short pulses of high gas temperatures under strictly homogeneous conditions. In our investigation, SiF/sub 4/ is used as the sensitizer to absorb energy from a pulsed CO/sub 2/ laser and to transfer this energy by collisions with the reactant gas. Ethyl chloride is used as an external standard ''thermometer'' gas to permit estimation of the unimolecular reaction rate constants by a relative rate approach. When UF/sub 6/ is the reactant, CF/sub 3/Cl is used as reagent to trap atomic fluorine reaction product, forming CF/sub 4/ as a stable indicator which is easily detected by infrared spectroscopy. Using these techniques, we estimate the UF/sub 6/ unimolecular reaction rate constant near the high-pressure limit. In the Appendix, we describe a computer program, written for the IBM PC, which predicts unimolecular rate constants based on the Rice-Ramsperger-Kassel theory. Parameterization of the theoretical model is discussed, and recommendations are made for ''appropriate'' input parameters for use in predicting the gas-phase unimolecular reaction rate for UF/sub 6/ as a function of temperature and gas composition and total pressure. 85 refs., 17 figs., 14 tabs.

  12. Selective Capture of Transcribed Sequences: A Promising Approach for Investigating Bacterium-Insect Interactions

    OpenAIRE

    Ruisheng An; Parwinder S. Grewal

    2012-01-01

    Bacterial interactions with eukaryotic hosts are complex processes which vary from pathogenic to mutualistic. Identification of bacterial genes differentially expressed in the host, promises to unravel molecular mechanisms driving and maintaining such interactions. Several techniques have been developed in the past 20 years to investigate bacterial gene expression within their hosts. The most commonly used techniques include in-vivo expression technology, signature-tagged mutagenesis, differe...

  13. Investigation for the extended application of melanoma Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    This issue is the Part B of the Progress Report (III) which includes our latest research results focusing mainly on the successful treatment of the first human melanoma patient who had metastasis in the scalp region. We also include the subsequent clinical treatment of various types of human primary melanoma lesions and the additional basic investigations necessary to perform the treatment. (J.P.N.)

  14. Comparison of collision-induced dissociation and electron-induced dissociation of phillyrin using FT-ICR MS.

    Science.gov (United States)

    Lin, Zhenguang; Lin, Zhiwei; Mu, Yingdi; Yan, Dong

    2016-10-01

    Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry using collision-induced dissociation (CID) and electron capture dissociation (ECD) at high mass resolution was first applied to investigate the characteristic fragment ions of phillyrin. The CID experimental results demonstrated the elemental composition of fragment ions unambiguously, so a reasonable fragmentation pathway of phillyrin was proposed. The ECD fragmentation mechanism was believed to be fundamentally different from the CID method. ECD could be used not only in the biological field but also as a powerful complement to the structural identification of small molecular compounds. The characteristic fragmentation pathways were helpful in analyzing and interpreting the stability and property of the parent ion. PMID:27258687

  15. Neutron Capture and Neutron Halos

    OpenAIRE

    A.Mengoni; Otsuka, T; Nakamura, T.(International Center for Elementary Particle Physics and Department of Physics, The University of Tokyo, Tokyo, Japan); Ishihara, M.

    1996-01-01

    The connection between the neutron halo observed in light neutron rich nuclei and the neutron radiative capture process is outlined. We show how nuclear structure information such as spectroscopic factors and external components of the radial wave function of loosely bound states can be derived from the neutron capture cross section. The link between the direct radiative capture and the Coulomb dissociation process is elucidated.

  16. Investigation of photoneutron and capture gamma-ray production in Pb and W under irradiation from 16N decay radiation

    International Nuclear Information System (INIS)

    Highlights: • MCNP used to investigate (γ,n) and (n,γ) in Pb and W due to interaction with 16N decay γ-rays and β. • Evidence of photoneutrons and capture gamma rays observed. • Bremsstrahlung from 16N beta spectrum insufficient to generate photoneutrons. - Abstract: Lead and tungsten are potential alternative materials for shielding reactor ex-core components with high 16N activity when available space limits application of concrete. Since the two materials are vulnerable to photonuclear reactions, the nature and intensity of the secondary radiation resulting from (γ,n) and (n,γ) reactions when 16N decay radiation interact with these materials need to be well known for effective shielding design. In this study the MCNP code was used to calculate the photoneutron and capture gamma-ray spectra in the two materials when irradiated by 16N decay radiation. It was observed that some of the photoneutrons generated in the two materials lie in the low-energy range which is considered optimum for (n,γ) reactions. Lead is more transparent to the photoneutrons when compared to tungsten. The calculations also revealed that the bremsstrahlung generated by the beta spectrum was not sufficient to trigger any additional photoneutrons. Both energetic and less energetic capture gamma-rays are observed when photoneutrons interact with nuclei of the two materials. Depending on the strength of the 16N source term, the secondary radiation could affect the effectiveness of the shield and need to be considered during design

  17. Theoretical Investigation of Hydrogen Adsorption and Dissociation on Iron and Iron Carbide Surfaces Using the ReaxFF Reactive Force Field Method

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Chenyu; van Duin, Adri C.T.; Sorescu, Dan C.

    2012-06-01

    We have developed a ReaxFF reactive force field to describe hydrogen adsorption and dissociation on iron and iron carbide surfaces relevant for simulation of Fischer–Tropsch (FT) synthesis on iron catalysts. This force field enables large system (>>1000 atoms) simulations of hydrogen related reactions with iron. The ReaxFF force field parameters are trained against a substantial amount of structural and energetic data including the equations of state and heats of formation of iron and iron carbide related materials, as well as hydrogen interaction with iron surfaces and different phases of bulk iron. We have validated the accuracy and applicability of ReaxFF force field by carrying out molecular dynamics simulations of hydrogen adsorption, dissociation and recombination on iron and iron carbide surfaces. The barriers and reaction energies for molecular dissociation on these two types of surfaces have been compared and the effect of subsurface carbon on hydrogen interaction with iron surface is evaluated. We found that existence of carbon atoms at subsurface iron sites tends to increase the hydrogen dissociation energy barrier on the surface, and also makes the corresponding hydrogen dissociative state relatively more stable compared to that on bare iron. These properties of iron carbide will affect the dissociation rate of H{sub 2} and will retain more surface hydride species, thus influencing the dynamics of the FT synthesis process.

  18. Investigation of correlations in the breakup of He{sup 8}; Etude des correlations dans la dissociation de l'He{sup 8}

    Energy Technology Data Exchange (ETDEWEB)

    Laurent, B

    2007-11-15

    Correlations in light neutron-rich nuclei are of considerable importance in understanding their structure. In this context the breakup of He{sup 8} into He{sup 6} + 2n has been investigated at 15 MeV/nucleon. The measurements were undertaken using a setup composed of two detector arrays: CHARISSA to detect the charged fragments and DEMON to detect the neutrons. The interpretation of the results was facilitated using a Monte Carlo simulation which was developed to take into account the correlations, the reaction and the experimental setup. Two techniques were used to study the correlations in the breakup of He{sup 8}. The first, intensity interferometry, provides, via the construction of the neutron-neutron correlation function, for a first estimate of the source size and thus the average separation between the neutrons. The second, using Dalitz plots, allows both the neutron-neutron and core-neutron correlations to be probed. Here, sequential decay via the ground state resonance of He{sup 7} and has been found to dominate the dissociation of He{sup 8}. The spatial and temporal characteristics of the breakup of He{sup 8} have thus been deduced and a root-mean-square separation between the two valence neutrons in the continuum states was estimated to be (7.3 {+-} 0.6) fm with a time delay between their emission of (1000 {+-} 300) fm/c. (author)

  19. Spectroscopic Investigation of the Canopy Configurations in Nanoparticle Organic Hybrid Materials of Various Grafting Densities during CO 2 Capture

    KAUST Repository

    Petit, Camille

    2012-01-12

    Novel liquid-like nanoparticle organic hybrid materials (NOHMs) made of polyetheramine chains tethered onto functionalized silica nanoparticles were synthesized and characterized before and after exposure to CO 2 using NMR, Raman, and ATR FT-IR spectroscopies in order to investigate the effect of the grafting densities on the NOHM canopy structure. Considering the promising tunable properties for CO 2 capture of NOHMs, this study was conducted to provide important structural information to better design NOHMs for CO 2 capture. In order to minimize the CO 2 absorption via enthalpic effect and provide a more accurate assessment of the structural effects, the NOHMs were synthesized without task-specific groups. A greater chain ordering and decreased intermolecular interactions were observed in NOHMs compared to the unbound polymer. This was attributed to the specific structural arrangement of the frustrated canopy. The distinct configuration of grafted polymer chains caused different CO 2 packing and CO 2-induced swelling behaviors between the NOHMs and the unbound polymer. The grafting density influenced the ordering and coupling of the polymer chains and CO 2-induced swelling. Its effect on the CO 2 packing behavior was less pronounced. © 2011 American Chemical Society.

  20. Capturing Thoughts, Capturing Minds?

    DEFF Research Database (Denmark)

    Nielsen, Janni

    2004-01-01

    Think Aloud is cost effective, promises access to the user's mind and is the applied usability technique. But 'keep talking' is difficult, besides, the multimodal interface is visual not verbal. Eye-tracking seems to get around the verbalisation problem. It captures the visual focus of attention....... However, it is expensive, obtrusive and produces huge amount of data. Besides, eye-tracking do not give access to user's mind. Capturing interface/cursor tracking may be cost effective. It is easy to install, data collection is automatic and unobtrusive and replaying the captured recording to the user and...

  1. Geochemical and Mineralogical Investigation for Carbon Capture and Storage, Within the Arbuckle Aquifer, Kansas

    Science.gov (United States)

    Datta, S.; Campbell, B.; Vega, M.; Barker, R. L.; Holubnyak, E.; Watney, W. L.

    2013-12-01

    A class VI permit site under U.S. Department of Energy has been proposed for carbon sequestration in south-central Kansas. In an effort to maintain environmental stability three wells have been drilled to basement rock, two being near the injection site, KGS 1-32 and KGS 1-28, and one being to the western annex, Cutter KGS #1. The western annex site, Cutter, is being utilized as a cross-comparison for mineralogical, geochemical, and structural component to the eastern sites in Wellington. A link will be determined of the continuity of three zones of interest: the Mississippian pay zone (3670'-3700'), a potential baffle zone in the upper Arbuckle (4400'-4550'), and the proposed CO2 injection zone (4900'-5050'). 11 depths within Cutter have been swabbed, and samples taken to investigate the chemistry of the subsurface formation water. The different depths will allow for a quantitative determination of how the brine composition varies with depth, and also provides a baseline for future monitoring. Initial chemical analysis by ICP-OES and HR-ICP-MS show a hyper saline brine (50,000-190,000TDS), dominated by Cl, Na, and Ca ions. pH ranges from 6.4 to 7.5, and total alkalinity from 124 and 378 mg/L of HCO¬3-. One complex, yet intriguing, species is Iron. It could potentially allow for further precipitation of the CO2¬ from the formation of Fe carbonates, such as siderite. Cores and thin sections were taken from a variety of depths ranging from 3681.9' to 5176.9' (Wellington) and 5564.3' to 7540.2' (Cutter). Dominant mineralogy consists of dolomite with varying forms of silicic intrusions, usually in the form of chert nodules with sulfide minerals and argillaceous materials in between. Extensive vugs and microfractures allow for varying porosity within each interval. Pay zone rocks typically display fine-grained cherty dolomite with subhedral to euhedral dolomite rhombs as well as oil stains oriented in parallel blotches. Characteristics such as high porosity and small

  2. Characteristics of CO2 Hydrate Formation and Dissociation in Glass Beads and Silica Gel

    OpenAIRE

    Qingping Li; Jiafei Zhao; Yu Liu; Xuke Ruan; Yongchen Song; Mingjun Yang

    2012-01-01

    CO 2 hydrate formation and dissociation is crucial for hydrate-based CO 2 capture and storage. Experimental and calculated phase equilibrium conditions of carbon dioxide (CO 2 ) hydrate in porous medium were investigated in this study. Glass beads were used to form the porous medium. The experimental data were generated using a graphical method. The results indicated the decrease of pore size resulted in the increase of the equilibrium pressure of CO 2 hydrate. Magnetic resonance imaging (MRI...

  3. Sedation and dissociative anaesthesia in the horse

    OpenAIRE

    Marntell, Stina

    2004-01-01

    The overall aim of this investigation was to study the effects of different drug combinations for premedication and dissociative anaesthesia, to examine their suitability for field conditions and their ability to maintain cardiorespiratory function and provide sufficient analgesia for common, but challenging procedures such as castration. Haemodynamic parameters, pulmonary ventilation-perfusion relationships, and clinical effects were studied during sedation and dissociative anaesthesia. The ...

  4. Numerical investigation of volume of fluid and level set interface capturing methods for bubble growth and detachment

    International Nuclear Information System (INIS)

    The injection of an air bubble in a liquid at rest is an interface flow problem where surface tension and its modeling at solid boundaries is a key factor. It is the subject of this study. Numerical simulations have been performed to study 3D axi-symmetrical bubble growth from an orifice through a horizontal wall. The gas inflow velocity used was sufficiently small to ensure that the bubble growth is quasi-static so that surface tension and buoyancy forces are dominant. The wall was considered non-wettable to avoid spreading of the interface along the wall. The Navier-Stokes equations were solved with two different interface capturing methods based on Volume of Fluid (VOF) and Level Set (LS) as well as coupled CVOFLS. In the VOF method the bubble interface was tracked using either an algebraic solver which results in some diffusion of the interface (compressive scheme implemented in OpenFOAM), or it was determined using a geometric reconstruction scheme (Geo-Reconstruct Scheme from Fluent). The TransAT code was used for the LS model which captures the interface using signed distance function. The bubble volume and center of gravity have been investigated during the growth using the three solvers and numerical results have been assessed against experimental data. These results have shown that reconstructing the interface using the LS method gives good agreement with the experiments. In VOF (compressive scheme), the bubble detaches at earlier times resulting in a smaller detachment volume. The coupled CVOFLS-GeoReconstruct was found to be more computationally expensive than the VOF-GeoReconstruct and to present bubble oscillation during the growth.

  5. Spontaneous dissociation of Co2(CO8 and autocatalytic growth of Co on SiO2: A combined experimental and theoretical investigation

    Directory of Open Access Journals (Sweden)

    Kaliappan Muthukumar

    2012-07-01

    Full Text Available We present experimental results and theoretical simulations of the adsorption behavior of the metal–organic precursor Co2(CO8 on SiO2 surfaces after application of two different pretreatment steps, namely by air plasma cleaning or a focused electron beam pre-irradiation. We observe a spontaneous dissociation of the precursor molecules as well as autodeposition of cobalt on the pretreated SiO2 surfaces. We also find that the differences in metal content and relative stability of these deposits depend on the pretreatment conditions of the substrate. Transport measurements of these deposits are also presented. We are led to assume that the degree of passivation of the SiO2 surface by hydroxyl groups is an important controlling factor in the dissociation process. Our calculations of various slab settings, using dispersion-corrected density functional theory, support this assumption. We observe physisorption of the precursor molecule on a fully hydroxylated SiO2 surface (untreated surface and chemisorption on a partially hydroxylated SiO2 surface (pretreated surface with a spontaneous dissociation of the precursor molecule. In view of these calculations, we discuss the origin of this dissociation and the subsequent autocatalysis.

  6. Investigations of primary and secondary amine carbamate stability by 1H NMR spectroscopy for post combustion capture of carbon dioxide

    International Nuclear Information System (INIS)

    Highlights: ► Carbamate stability constants of series of amines have been measured at (288 to 318) K. ► Standard molar enthalpies and entropies have been determined by van’t Hoff analyses. ► A ΔHmo-ΔSmo plot for carbamate formation gives a linear relationship. ► This relationship provides a guide for the selection of amines for PCC applications. ► Stereochemical effects and intramolecular H-bonding affect carbamate formation. - Abstract: Carbamate formation is one of the major chemical reactions that can occur in solution in the capture of CO2 by amine-based solvents, and carbamate formation makes a significant enthalpy contribution to the absorption-desorption of CO2 that occurs in the absorber/stripper columns of the PCC process. Consequently, the formation of carbamates of selected series of primary and secondary amines over the temperature range (288 to 318) K has been investigated by equilibrium 1H NMR studies, and the stability constants (K9) for the equilibrium: RNH2+HCO3-⇄K9RNHCOO-+H2O are reported. van’t Hoff analyses have resulted in standard molar enthalpies, ΔHmo, and entropies, ΔSmo, of carbamate formation. A ΔHmo-ΔSmo plot generates a linear correlation for carbamate formation (providing a mean standard molar free energy, ΔGmo, for carbamate formation of about −7 kJ · mol−1), and this relationship helps provide a guide to the selection of an amine(s) solvent for CO2 capture, in terms of enthalpy considerations. A linear ΔHmo-ΔSmo plot also occurs for carbamate protonation. The formation of the carbamates has been correlated with systematic changes in composition and structure, and steric effects have been identified by comparing molecular geometries obtained using density functional B3LYP/6-311++G(d,p) calculations. Trends in steric effects have been identified in the series of compounds monoethanolamine (MEA), 1-amino-2-propanol, 2-amino-1-propanol (AP) and 2-amino-2-methyl-1-propanol (AMP). In the case of 2

  7. The expectancy of threat and peritraumatic dissociation

    Directory of Open Access Journals (Sweden)

    Pamela McDonald

    2013-12-01

    Full Text Available Background: Peritraumatic dissociation is one of the most critical acute responses to a traumatic experience, partly because it predicts subsequent posttraumatic stress disorder. Despite this, there is little understanding about the factors that influence peritraumatic dissociation. This study investigated the extent to which peritraumatic dissociation is predicted by the amount of perceived warning that participants had of the impact of the trauma. Method: Randomized eligible admissions to four major trauma hospitals (N =243 were assessed during hospital admission with the Peritraumatic Dissociation Experiences Questionnaire (PDEQ and the perceived warning that participants had before the trauma impact occurred. Results: Whereas female gender predicted both Awareness and Derealization subscale scores on the PDEQ, perceived warning also predicted scores on the Derealization subscale. Conclusions: This finding suggests that the degree of anticipated threat may contribute to peritraumatic dissociation.

  8. Catalytic methanol dissociation

    International Nuclear Information System (INIS)

    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

  9. What contributes to predicting change in the treatment of dissociation: initial levels of dissociation, PTSD, or overall distress?

    Science.gov (United States)

    Brand, Bethany L; Stadnik, Ryan

    2013-01-01

    Individuals with dissociative disorders (DDs) suffer from high levels of dissociation as well as posttraumatic stress disorder (PTSD) and general distress. No research has investigated how changes in dissociation relate to changes in other symptoms over the course of treatment in patients with DD. Using a prospective, naturalistic design, we collected reports of symptoms from a sample of therapists and their patients diagnosed with dissociative identity disorder or dissociative disorder not otherwise specified who participated in the Treatment Outcome of Patients with Dissociative Disorders study. The patients completed surveys at intake (Time 1) into the study and at 30-month follow-up (Time 4). We found that dissociative symptoms, including amnesia, depersonalization/derealization, and absorption, at the initial assessment of the study ("initial") were related to initial levels of PTSD and general distress and that changes in dissociative symptoms were related to changes in PTSD and general distress. Initial dissociation was a significant predictor of change in dissociation at 30 months when we controlled for length of time for follow-up, length of time practicing therapy, and length of time treating dissociative patients. Our results suggest that a reduction in dissociative symptoms in DD patients is associated with reductions in the overall severity of dissociative, posttraumatic stress, and distress symptoms. PMID:23627481

  10. 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.

  11. Correlations in hadron diffraction dissociation

    International Nuclear Information System (INIS)

    Hadron diffractive dissociation reactions are studied based on three component Deck model. The correlations between the mass in dissociated particle subsystem and the dissociation angle/or partial waves) defined in gottfried-Jackson system, are interpreted. Several reactions with different spin and parity structures in dissociative verticles, are studied. The three component Deck model is extended to dissociation of light nuclei, in particular the deuteron dissociation. (M.C.K.)

  12. Loop facility for investigating of BRIG-300 reactor fuel elements with dissociating N2O4 coolant on ''Mariya'' reactor (PPR)

    International Nuclear Information System (INIS)

    The construction of a gas-cooled loop facility with a dissociating coolant N2O4 is designed that allows the fuel element to be tested under the simultaneous effect of the reactor irradiation and chemically active N2O4 with fast neutron density of (4-6)x1014 neutr./(cm2xs) and pressure of 16.0 MPa. The schematic drawing of the facility and loop channel construction are presented. The principle of the facility operation is described

  13. Energy distribution in dissociations of polyatomic molecules

    International Nuclear Information System (INIS)

    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 (CH3Cl) and the acetylradical (CH3CO). 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

  14. 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.)

  15. Reach tracking reveals dissociable processes underlying cognitive control.

    Science.gov (United States)

    Erb, Christopher D; Moher, Jeff; Sobel, David M; Song, Joo-Hyun

    2016-07-01

    The current study uses reach tracking to investigate how cognitive control is implemented during online performance of the Stroop task (Experiment 1) and the Eriksen flanker task (Experiment 2). We demonstrate that two of the measures afforded by reach tracking, initiation time and reach curvature, capture distinct patterns of effects that have been linked to dissociable processes underlying cognitive control in electrophysiology and functional neuroimaging research. Our results suggest that initiation time reflects a response threshold adjustment process involving the inhibition of motor output, while reach curvature reflects the degree of co-activation between response alternatives registered by a monitoring process over the course of a trial. In addition to shedding new light on fundamental questions concerning how these processes contribute to the cognitive control of behavior, these results present a framework for future research to investigate how these processes function across different tasks, develop across the lifespan, and differ among individuals. PMID:27045465

  16. Dissociated Prostate Regeneration under the Renal Capsule.

    Science.gov (United States)

    Zong, Yang; Goldstein, Andrew S; Witte, Owen N

    2015-11-01

    Tissue recombination models are useful for studying cancer initiation, progression, and metastasis. They also provide an in vivo environment in which to investigate the functional role of stem cells in tissue repair. In this protocol, we describe in detail the dissociated prostate regeneration assay. Dissociated adult murine prostate cells are combined with embryonic urogenital sinus mesenchymal cells and implanted under the renal capsule. Morphological tissue structures with appropriate epithelial-stroma interactions are reconstituted in the grafts. PMID:26527760

  17. Neutron Capture Nucleosynthesis

    OpenAIRE

    Kiss, Miklos

    2016-01-01

    Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. We have proposed a simple unified model to investigate the neutron capture nucleosynthesis in arbitrary neutron density environment. We have also investigated what neutron density is required to reproduce the measured abundance of nuclei assuming equilibrium processes. We found both of these that the medium neutron density has a particularly important role at neutron capture nucleosynthesis. About these resu...

  18. Theoretical investigation of energy deposition and electron capture cross-sections for helium ion impact on formaldehyde

    International Nuclear Information System (INIS)

    The subject of the work presented here is related to damage caused by energetic, charged particle radiation such as electrons, protons, and alpha particles to prebiotic matter such as that found in interstellar space. The calculations are carried out using an all electron, all nuclei, scheme that explicitly treats the electron-nuclear coupling. We present results for the no-capture, as well as the single and double electron capture probabilities, as well as for the 1s and 2l (l = s, p) contributions to the electron capture cross-sections of 3He2+ projectiles on formaldehyde molecules. We find that the summed cross-section peaks at 10 keV/amu, and has a plateau between 0.1 and 1 keV/amu. We also present preliminary results for the nuclear, ro-vibrational and electronic stopping cross-section. We find a large contribution to the electronic stopping cross-section and a maximum shifted towards higher energies in the nuclear stopping cross-section, when compared to SRIM results. We interpret this to be a consequence of molecular bonding

  19. Theoretical investigation of energy deposition and electron capture cross-sections for helium ion impact on formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera-Trujillo, R. [Quantum Theory Project, University of Florida, P.O. Box 118435, Gainesville, FL 32611-8435 (United States); Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, Cuernavaca, Morelos, 62251 (Mexico); Sabin, John R. [Quantum Theory Project, University of Florida, P.O. Box 118435, Gainesville, FL 32611-8435 (United States)]. E-mail: sabin@qtp.ufl.edu; Deumens, Erik [Quantum Theory Project, University of Florida, P.O. Box 118435, Gainesville, FL 32611-8435 (United States); Ohrn, Yngve [Quantum Theory Project, University of Florida, P.O. Box 118435, Gainesville, FL 32611-8435 (United States)

    2007-08-15

    The subject of the work presented here is related to damage caused by energetic, charged particle radiation such as electrons, protons, and alpha particles to prebiotic matter such as that found in interstellar space. The calculations are carried out using an all electron, all nuclei, scheme that explicitly treats the electron-nuclear coupling. We present results for the no-capture, as well as the single and double electron capture probabilities, as well as for the 1s and 2l (l = s, p) contributions to the electron capture cross-sections of {sup 3}He{sup 2+} projectiles on formaldehyde molecules. We find that the summed cross-section peaks at 10 keV/amu, and has a plateau between 0.1 and 1 keV/amu. We also present preliminary results for the nuclear, ro-vibrational and electronic stopping cross-section. We find a large contribution to the electronic stopping cross-section and a maximum shifted towards higher energies in the nuclear stopping cross-section, when compared to SRIM results. We interpret this to be a consequence of molecular bonding.

  20. Neutron Capture Nucleosynthesis

    CERN Document Server

    Kiss, Miklos

    2016-01-01

    Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. We have proposed a simple unified model to investigate the neutron capture nucleosynthesis in arbitrary neutron density environment. We have also investigated what neutron density is required to reproduce the measured abundance of nuclei assuming equilibrium processes. We found both of these that the medium neutron density has a particularly important role at neutron capture nucleosynthesis. About these results most of the nuclei can formed at medium neutron capture density environment e.g. in some kind of AGB stars. Besides these observations our model is capable to use educational purpose.

  1. Experimental investigations of electron capture from atomic hydrogen and deuterium by alpha particles. Final report, September 15, 1984--September 14, 1993

    International Nuclear Information System (INIS)

    The authors have succeeded in making state-selective measurements of charge capture by doubly-ionized helium colliding with ground-state neutral helium atoms, but failed to achieve the primary goal, which was to investigate atomic hydrogen targets. They discuss a number of ancillary experiments and calculations of relevance for fusion energy production that they have done. Reprints and preprints of publications resulting from this work are contained in an appendix

  2. Investigation of photoneutron and capture gamma-ray production in Pb and W under irradiation from 16N decay radiation

    Science.gov (United States)

    Kebwaro, Jeremiah Monari; Zhao, Yaolin; He, Chaohui

    2015-09-01

    Lead and tungsten are potential alternative materials for shielding reactor ex-core components with high 16N activity when available space limits application of concrete. Since the two materials are vulnerable to photonuclear reactions, the nature and intensity of the secondary radiation resulting from (γ,n) and (n,γ) reactions when 16N decay radiation interact with these materials need to be well known for effective shielding design. In this study the MCNP code was used to calculate the photoneutron and capture gamma-ray spectra in the two materials when irradiated by 16N decay radiation. It was observed that some of the photoneutrons generated in the two materials lie in the low-energy range which is considered optimum for (n,γ) reactions. Lead is more transparent to the photoneutrons when compared to tungsten. The calculations also revealed that the bremsstrahlung generated by the beta spectrum was not sufficient to trigger any additional photoneutrons. Both energetic and less energetic capture gamma-rays are observed when photoneutrons interact with nuclei of the two materials. Depending on the strength of the 16N source term, the secondary radiation could affect the effectiveness of the shield and need to be considered during design.

  3. The impact of dissociation on the development and maintenance of posttraumatic stress disorder

    NARCIS (Netherlands)

    Hagenaars, M.A.

    2008-01-01

    This dissertation investigated the impact of dissociation on the development of posttraumatic stress disorder (PTSD), on memory formation, and on treatment efficacy. First, the predictive power of peritraumatic psychological and somatoform dissociation was investigated in two studies using a prospec

  4. Peritraumatic and Persistent Dissociation as Predictors of PTSD Symptoms in a Female Cohort

    OpenAIRE

    Werner, Kimberly B.; Griffin, Michael G.

    2012-01-01

    Recent research has investigated peritraumatic and persistent dissociation as a possible predictive factor for posttraumatic stress disorder (PTSD). The current study aims to add to this literature by examining dissociative responses in female assault survivors (N = 92 initial assessment; n = 62 follow-up). Dissociative symptoms experienced at 3 time points were assessed: peritraumatic dissociation, persistent dissociation - initial (M = 28.2 days post trauma) and follow-up (M = 224.9 days po...

  5. Duality in diffraction dissociations

    International Nuclear Information System (INIS)

    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

  6. The production of CO+(A 2Π) from dissociative ionization of CO2: a fragment ion-photon coincidence spectroscopic investigation

    International Nuclear Information System (INIS)

    Fragment ion-photon coincidence (FIPCO) spectra by 120 eV electron impact on carbon dioxide (CO2) have been observed, in which optical emission in the 250-600 nm region has been detected. There are a dominant CO2+ peak and a weak, broad CO+ peak in the FIPCO spectra. The kinetic energy distribution of CO+ correlated with the CO+(A 2Π-X 2Σ+) emission has been estimated on the basis of the Monte Carlo simulation of the CO+ band shape. This CO+(A 2Π) ion is produced through the dissociation process, CO2+e-→CO2+*[MET I 2Πu] + 2e-→CO+(A 2Π) + O(3P) + 2e-, where MET refers to multiple electron transitions. The production of CO+(B 2Σ+) is negligible compared with that of CO+(A 2Π). The produced CO+(A 2Π) ion is in vibrationally excited levels, and there is little population in the vibrational levels, v'≤3. (author)

  7. An investigation of the effects of experimental parameters on the closed-loop control of photoionization/dissociation processes in acetophenone

    International Nuclear Information System (INIS)

    The photodissociation channels of acetophenone (C6H5)-CO-(CH3), can be controlled by the use of tailored strong-field laser pulses together with a feedback loop incorporating an adaptive algorithm. This optimal control strategy is used to selectively cleave either the OC-CH3 or OC-C6H5 bonds, monitored by detecting either mass 105 or 77, respectively. Varying the pulse chirp and duration prior to optimization is shown to affect the dynamic range of control. We show that it is possible to decrease the search space by limiting the retardance range of the spatial light modulator (SLM), or by decreasing the number of frequency elements manipulated by the SLM, and still achieve a certain degree of control over acetophenone dissociation. Performing consecutive experiments with identical experimental parameters and search criteria reveals that the learning algorithm may find solutions that have the same degree of control (various local solutions), with either similar SLM retardances or markedly different retardances. Comparison of the dynamic range of control between single-parameter optimizations (pulse energy and duration) with the tailored electric field profiles generated by the adaptive algorithm reveals an enhancement in the control of reaction product distributions in the latter scheme

  8. Dissociative charge exchange of H2+

    International Nuclear Information System (INIS)

    This thesis is devoted to molecular dissociation, in particular the dissociation of the hydrogen molecule H2 arising from electron capture of its ion H2+ 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 H2+ with Ar, Mg, Na and Cs targets at keV energies are described in Chapter V. The predissociation of the c3PIsub(u)-state of H2 populated after charge exchange of H2 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 H2+ with alkali targets are discussed. The last chapter deals with predissociation of highly excited states in H2. (Auth.)

  9. Dissociative recombination of N2H+

    Science.gov (United States)

    dos Santos, S. Fonseca; Ngassam, V.; Orel, A. E.; Larson, Å.

    2016-08-01

    The direct and indirect mechanisms of dissociative recombination of N2H+ are theoretically studied. At low energies, the electron capture is found to be driven by recombination into bound Rydberg states, while at collision energies above 0.1 eV, the direct capture and dissociation along electronic resonant states becomes important. Electron-scattering calculations using the complex Kohn variational method are performed to obtain the scattering matrix as well as energy positions and autoionization widths of resonant states. Potential-energy surfaces of electronic bound states of N2H and N2H+ are computed using structure calculations with the multireference configuration interaction method. The cross section for the indirect mechanism is calculated using a vibrational frame transformation of the elements of the scattering matrix at energies just above the ionization threshold. Here vibrational excitations of the ionic core from v =0 to v =1 and v =2 for all three normal modes are considered and autoionization is neglected. The cross section for the direct dissociation along electronic resonant states is computed with wave-packet calculations using the multiconfiguration time-dependent Hartree method, where all three internal degrees of freedom are considered. The calculated cross sections are compared to measurements.

  10. 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

    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...

  11. Investigation of Ester- and Amide-Linker-Based Porous Organic Polymers for Carbon Dioxide Capture and Separation at Wide Temperatures and Pressures.

    Science.gov (United States)

    Ullah, Ruh; Atilhan, Mert; Anaya, Baraa; Al-Muhtaseb, Shaheen; Aparicio, Santiago; Patel, Hasmukh; Thirion, Damien; Yavuz, Cafer T

    2016-08-17

    Organic compounds, such as covalent organic framework, metal-organic frameworks, and covalent organic polymers have been under investigation to replace the well-known amine-based solvent sorption technology of CO2 and introduce the most efficient and economical material for CO2 capture and storage. Various organic polymers having different function groups have been under investigation both for low and high pressure CO2 capture. However, search for a promising material to overcome the issues of lower selectivity, less capturing capacity, lower mass transfer coefficient and instability in materials performance at high pressure and various temperatures is still ongoing process. Herein, we report synthesis of six covalent organic polymers (COPs) and their CO2, N2, and CH4 adsorption performances at low and high pressures up to 200 bar. All the presented COPs materials were characterized by using elemental analysis method, Fourier transform infrared spectroscopy (FTIR) and solid state nuclear magnetic resonance (NMR) spectroscopy techniques. Physical properties of the materials such as surface areas, pore volume and pore size were determined through BET analysis at 77 K. All the materials were tested for CO2, CH4, and N2 adsorption using state of the art equipment, magnetic suspension balance (MSB). Results indicated that, amide based material i.e. COP-33 has the largest pore volume of 0.2 cm(2)/g which can capture up to the maximum of 1.44 mmol/g CO2 at room temperature and at pressure of 10 bar. However, at higher pressure of 200 bar and 308 K ester-based compound, that is, COP-35 adsorb as large as 144 mmol/g, which is the largest gas capturing capacity of any COPs material obtained so far. Importantly, single gas measurement based selectivity of COP-33 was comparatively better than all other COPs materials at all condition. Nevertheless, overall performance of COP-35 rate of adsorption and heat of adsorption has indicated that this material can be considered for

  12. Investigation of model capability in capturing vertical hydrodynamic coastal processes: a case study in the north Adriatic Sea

    Science.gov (United States)

    McKiver, W. J.; Sannino, G.; Braga, F.; Bellafiore, D.

    2016-01-01

    In this work we consider a numerical study of hydrodynamics in the coastal zone using two different models, SHYFEM (shallow water hydrodynamic finite element model) and MITgcm (Massachusetts Institute of Technology general circulation model), to assess their capability to capture the main processes. We focus on the north Adriatic Sea during a strong dense water event that occurred at the beginning of 2012. This serves as an interesting test case to examine both the models strengths and weaknesses, while giving an opportunity to understand how these events affect coastal processes, like upwelling and downwelling, and how they interact with estuarine dynamics. Using the models we examine the impact of setup, surface and lateral boundary treatment, resolution and mixing schemes, as well as assessing the importance of nonhydrostatic dynamics in coastal processes. Both models are able to capture the dense water event, though each displays biases in different regions. The models show large differences in the reproduction of surface patterns, identifying the choice of suitable bulk formulas as a central point for the correct simulation of the thermohaline structure of the coastal zone. Moreover, the different approaches in treating lateral freshwater sources affect the vertical coastal stratification. The results indicate the importance of having high horizontal resolution in the coastal zone, specifically in close proximity to river inputs, in order to reproduce the effect of the complex coastal morphology on the hydrodynamics. A lower resolution offshore is acceptable for the reproduction of the dense water event, even if specific vortical structures are missed. Finally, it is found that nonhydrostatic processes are of little importance for the reproduction of dense water formation in the shelf of the north Adriatic Sea.

  13. Investigation of model capability in capturing vertical hydrodynamic coastal processes: a case study in the North Adriatic Sea

    Directory of Open Access Journals (Sweden)

    W. J. McKiver

    2015-08-01

    Full Text Available In this work we consider a numerical study of hydrodynamics in the coastal zone using two different models, SHYFEM and MITgcm, to assess their capability to capture the main processes. We focus on the North Adriatic Sea during a strong dense water event that occurred at the beginning of 2012. This serves as an interesting test case to examine both the models strengths and weaknesses, while giving an opportunity to understand how these events affect coastal processes, like upwelling and downwelling, and how they interact with estuarine dynamics. Using the models we examine the impact of setup, surface and lateral boundary treatment, resolution and mixing schemes, as well as assessing the importance of nonhydrostatic dynamics in coastal processes. Both models are able to capture the dense water event, though each displays biases in different regions. The models show large differences in the reproduction of surface patterns, identifying the choice of suitable bulk formulas as a central point for the correct simulation of the thermohaline structure of the coastal zone. Moreover, the different approaches in treating lateral freshwater sources affect the vertical coastal stratification. The results indicate the importance of having high horizontal resolution in the coastal zone, specifically in close proximity to river inputs, in order to reproduce the effect of the complex coastal morphology on the hydrodynamics. A lower resolution offshore is acceptable for the reproduction of the dense water event, even if specific vortical structures are missed. Finally, it is found that nonhydrostatic processes are of little importance for the reproduction of dense water formation in the shelf of the North Adriatic Sea.

  14. Quantum Chemistry Study on Dissociation of Oxalyl Bromide

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The multi-bond dissociation dynamics of oxalyl bromide ((BrCO)2) has been investigated by DFT and CIS calculations. Upon the results, conclusion could be drawn that dissociation of C-Br bond of oxalyl bromide at the ground state (S0) is of barrierless. After the absorption of a photon, (BrCO)2 is excited to the first excited state and one of its C-Br bonds is broken to yield dissociate.

  15. Dissociative Reactions to Incest.

    Science.gov (United States)

    Hall, J. Mark

    In contrast to Freud's later and revised view of the etiology of hysterical, or dissociative, symptoms, it is now known that real, and not fantasized, sexual experiences in childhood are experienced in disociative symptomatology. It is useful to understand that incest involves both traumatic events, that is, incidents of sexual violation per se,…

  16. Dissociation by acceleration

    OpenAIRE

    Peeters, K.; Zamaklar, M.

    2008-01-01

    We show that mesons, described using rotating relativistic strings in a holographic setup, undergo dissociation when their acceleration 'a' exceeds a value which scales with the angular momentum 'J' as a_max ~ \\sqrt{T_s/J}, where 'T_s' is the string tension.

  17. Dissociation by acceleration

    OpenAIRE

    2007-01-01

    We show that mesons, described using rotating relativistic strings in a holographic setup, undergo dissociation when their acceleration 'a' exceeds a value which scales with the angular momentum 'J' as a_max ~ \\sqrt{T_s/J}, where 'T_s' is the string tension.

  18. Sexuality of dissocial persons

    Directory of Open Access Journals (Sweden)

    Marta Janus

    2016-02-01

    Full Text Available Introduction. The development of personality disorders as well as sexual disorders is defined by the common time spectrum as well as deficits and changes in such areas as biological, environmental and mental area. Dissocial (antisocial personality disorder is characterised by a pervasive pattern of disregard for, or violation of, the rights of others. The indices of the discussed disorder can be found in specific patterns of social inadequacy occurring during childhood and puberty. At the same time, characteristic indices of social functioning at a young age often indicate subsequent dysfunctions in the area of sexuality. Aim. The aim of this paper is to explain sexual functioning of persons with dissocial personality disorder (including the relation with sexual dysfunctions, and to ascertain issues that need further empirical studies. Method. As a result of analysis of available literature (matched with EBSCO database search fulfilling criteria of sample size, accuracy of examination procedure, conclusions and discussion 5 articles fulfilling criteria cited above has been found. Conclusions: Based on literature overview, it appeared to be impossible to determine one coherent way of sexual functioning of dissocial persons, and to establish causal relationship of sexual dysfunctions and dissocial personality disorder. However, it is possible to indicate group of most characteristic dysfunctional sexual behaviours. Noteworthy, available publication analyse only selected aspects of sexual behaviours in small, homogenous groups. There is a lack of review studies as well as multi-faceted studies.

  19. Pathological Dissociation as Measured by the Child Dissociative Checklist

    Science.gov (United States)

    Wherry, Jeffrey N.; Neil, Debra A.; Taylor, Tamara N.

    2009-01-01

    The component structure of the Child Dissociative Checklist was examined among abused children. A factor described as pathological dissociation emerged that was predicted by participants being male. There also were differences in pathological dissociation between groups of sexually abused and physically abused children. Replication of this factor…

  20. Experimental and computational investigation of CO2 capture on amine grafted metal-organic framework NH2-MIL-101

    Science.gov (United States)

    Huang, Xiang; Lu, Jianfeng; Wang, Weilong; Wei, Xiaolan; Ding, Jing

    2016-05-01

    A standard metal-organic framework, NH2-MIL-101 based on chromium has been synthesized. For the purpose of offering more binding sites for CO2, post-synthetic modification of tetraethylenepentamine (TEPA) was conducted by using a wet impregnation method. With the aim of better understanding the thermodynamics and mechanisms of CO2 adsorption, molecular dynamics (MD) simulations have been used for structures optimization and adsorption kinetics of NH2-MIL-101/TEPA adsorbents, and the CO2 adsorption capacity with different TEPA loadings was simulated by the Monte Carlo (MC) method. Results confirmed that TEPA was successfully grafted on the coordinative unsaturated metal centers. At 1 bar and 298 K, NH2-MIL-101 combined with 50 wt% TEPA exhibited a CO2 uptake of 3.1 mmol/g-sorb. Under low loading of TEPA, the coordinative unsaturated metal centers made a relatively big contribution to CO2 adsorption. With more TEPA incorporated, the CO2 binding affinity was enhanced due to the existence of abundant amine groups. On the basis of both experimental and simulation analysis, this synthesized amine-grafted sorbent with excellent CO2 capture performance is an ideal material for greenhouse gas control.

  1. {sup 1}H and {sup 10}B NMR and MRI investigation of boron- and gadolinium-boron compounds in boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Bonora, M., E-mail: marco.bonora@unipv.it [Physics Department ' A. Volta' , University of Pavia, Via Bassi 6, 27100 Pavia (Italy)] [CNISM Unit (Italy); Corti, M.; Borsa, F. [Physics Department ' A. Volta' , University of Pavia, Via Bassi 6, 27100 Pavia (Italy)] [CNISM Unit (Italy); Bortolussi, S.; Protti, N.; Santoro, D.; Stella, S.; Altieri, S. [Nuclear and Theoretical Physics Department, University of Pavia, Via Bassi 6, 27100 Pavia (Italy)] [INFN Pavia (Italy); Zonta, C.; Clerici, A.M.; Cansolino, L.; Ferrari, C.; Dionigi, P. [Surgical Sciences Department, Experimental Surgery Laboratory, University of Pavia, Pavia (Italy); Porta, A.; Zanoni, G.; Vidari, G. [Organic Chemistry Department, University of Pavia, Via Taramelli 10, 27100 Pavia (Italy)

    2011-12-15

    {sup 10}B molecular compounds suitable for Boron Neutron Capture Therapy (BNCT) are tagged with a Gd(III) paramagnetic ion. The newly synthesized molecule, Gd-BPA, is investigated as contrast agent in Magnetic Resonance Imaging (MRI) with the final aim of mapping the boron distribution in tissues. Preliminary Nuclear Magnetic Resonance (NMR) measurements, which include {sup 1}H and {sup 10}B relaxometry in animal tissues, proton relaxivity of the paramagnetic Gd-BPA molecule in water and its absorption in tumoral living cells, are reported.

  2. Bond dissociation & electronegativity equalization

    OpenAIRE

    Verstraelen, Toon; Ayers, Paul W.; Van Speybroeck, Veronique; Waroquier, Michel

    2012-01-01

    It is well known that the Electrongativity Equalization Mtehod (EEM) fails to describe the charge distribution upon bond dissocation. In this presentation, the bond dissocation is studied with the Atom-Condensed Kohn-Sham DFT approximated to second order (ACKS2). After reviewing the basic equations, a two-fragment system is studied in the dissociation limit. The limiting behavior of the Coulomb interaction (1/r) and the Kohn-Sham matrix elements (exponentially decaying) are plugged into the e...

  3. Sexuality of dissocial persons

    OpenAIRE

    Marta Janus; Agata Szulc

    2016-01-01

    Introduction. The development of personality disorders as well as sexual disorders is defined by the common time spectrum as well as deficits and changes in such areas as biological, environmental and mental area. Dissocial (antisocial) personality disorder is characterised by a pervasive pattern of disregard for, or violation of, the rights of others. The indices of the discussed disorder can be found in specific patterns of social inadequacy occurring during childhood and puberty. At the sa...

  4. Investigation of photo-dissociation mechanism of methyl bromide with ultra short laser pulses%超短脉冲激光对溴甲烷的光解机理研究

    Institute of Scientific and Technical Information of China (English)

    张瑾; 马建国

    2012-01-01

    Experimental investigation was carried out on the photo-ionization and photo-dissociation channels of methyl bromide by using resonance enhanced multiphoton ionization time-of-flight mass spectrometer arid mass-selected excitation spectra. Then the mass signals were assigned to H+ , CHLm+ (m=0~3), iBr+ (i= 79, 81) and CHm'Br+0n=2; t=79, 81). Two resonant features of CH3+ were also determined. Finally, in the ultraviolet range of 279-287 nm, the dissociation channels of methyl bromide molecule, mainly showing as those of parent molecule, were given and analyzed%文章通过共振增强多光子电离飞行时间质谱和质量选择光电离激发谱,对溴甲烷分子的光电离和光解离通道进行了研究,并对部分碎片离子H+、CHm+(m=0~3)、(')Br+ (i=79,81)和CHm(2)Br+(m=2;i=79,81)的分质量激发谱进行了归属和标识;对CH3+的共振峰进行了确认;最后分析并给出了在279~287 nm紫外光波段内,溴甲烷分子以母体分子的解离通道为主的解离通道.

  5. 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.

  6. Psychometric validation of the State Scale of Dissociation (SSD).

    Science.gov (United States)

    Krüger, Christa; Mace, Chris J

    2002-03-01

    Although dissociative phenomena are often transient features of mental states, existing measures of dissociation are designed to measure enduring traits. A new present-state self-report measure, sensitive to changes in dissociative states, was therefore developed and psychometrically validated. Fifty-six items were formulated to measure state features, and sorted according to seven subscales: derealization, depersonalization, identity confusion, identity alteration, conversion, amnesia and hypermnesia. The State Scale of Dissociation (SSD) was administered with other psychiatric scales (DES, BDI, BAI, SCI-PANSS) to 130 participants with DSM-IV major depressive disorder schizophrenia, alcohol withdrawal, dissociative disorders and controls. In these sample populations, the SSD was demonstrated as a valid and reliable measure of changes in and the severity of dissociative states. Discriminant validity, content, concurrent, predictive, internal criterion-related, internal construct and convergent validities, and internal consistency and split-half reliability were confirmed statistically. Clinical observations of dissociative states, and their comorbidity with symptoms of depression and psychotic illness, were confirmed empirically. The SSD, an acceptable, valid and reliable scale measuring state features of dissociation at the time of completion, was obtained. This is a prerequisite for further investigation of correlations between changes in dissociative states and concurrent physiological parameters. PMID:12006198

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

    International Nuclear Information System (INIS)

    Dissociation of acetaldehyde in moderate strong laser field of 1013-1014 W/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

  8. 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.

  9. Coulomb dissociation in nonrelativistic and relativistic collisions

    International Nuclear Information System (INIS)

    Electromagnetic excitations in the Coulomb field of nuclei have been studied using quantum as well as semiclassical methods. Even at relatively modest incident energies, the Coulomb dissociation cross sections of projectiles with relatively low particle thresholds could be of sizeable order of magnitude. Such a study complements our knowledge about radiative capture processes, which are of interest for nuclear astrophysics. Quite a few questions remain to be answered, like the importance of nuclear interactions for small angle scattering, interference of different multipolarities for triple differentiial cross sections and distortion effects on the three-body final states. In the case of dissociation at relativistic energies it is shown that only for the total cross section both semiclassical and quantim-mechanical methods yield the same results. As an example the Primakoff effect is considered, where in an M1 excitation of ≅ 80 MeV a Λ hyperion is converted into a Σo hyperion by means of the virtual photon field of heavy target nuclei. Virtual photon spectra for all multipolarities can be calculated. This provides a sound basis for the analysis of electromagnetic dissociation experiments at relativistic heavy ion accelerators, like the BEVALAC. 10 figs., 25 refs

  10. Boron neutron capture therapy of brain tumors: investigation of urinary metabolites and oxidation products of sodium borocaptate by electrospray ionization mass spectrometry.

    Science.gov (United States)

    Gibson, C R; Staubus, A E; Barth, R F; Yang, W; Kleinholz, N M; Jones, R B; Green-Church, K; Tjarks, W; Soloway, A H

    2001-12-01

    Boron neutron capture therapy (BNCT) is based on a nuclear capture reaction that occurs when boron-10, a stable isotope, is irradiated with low energy neutrons to produce high-energy alpha particles and recoiling lithium-7 nuclei. The purpose of the present study was to determine what urinary metabolites, if any, could be detected in patients with brain tumors who were given sodium borocaptate (BSH), a drug that has been used clinically for BNCT. BSH was infused intravenously over a 1-h time period at doses of 26.5, 44.1, or 88.2 mg/kg of body weight to patients with high-grade brain tumors. Electrospray ionization mass spectrometry has been used to investigate possible urinary metabolites of BSH. Chemical and instrument conditions were established to detect BSH and its possible metabolites in both positive and negative electrospray ionization modes. Using this methodology, boronated ions were found in patients' urine samples that appeared to be consistent with the following chemical structures: BSH sulfenic acid (BSOH), BSH sulfinic acid (BSO(2)H), BSH disulfide (BSSB), BSH thiosulfinate (BSOSB), and a BSH-S-cysteine conjugate (BSH-CYS). Although BSH has been used clinically for BNCT since the late 1960s, this is the first report of specific biotransformation products following administration to patients. Further studies will be required to determine both the biological significance of these metabolites and whether any of these accumulate in significant amounts in brain tumors. PMID:11717178

  11. Histopathology investigation on the Vardar chub (Squalius vardarensis) populations captured from the rivers impacted by mining activities.

    Science.gov (United States)

    Jordanova, Maja; Rebok, Katerina; Dragun, Zrinka; Ramani, Sheriban; Ivanova, Lozenka; Kostov, Vasil; Valić, Damir; Krasnići, Nesrete; Filipović Marijić, Vlatka; Kapetanović, Damir

    2016-07-01

    Many natural freshwater ecosystems, especially in the north eastern Macedonia, are polluted with heavy metals, which are released by active mines. Long-term exposure to high levels of dissolved metals might result in increased metal bioaccumulation in organs of aquatic organisms, and consequently might cause various sub-toxic and toxic effects. The aim of this study was to assess the health of Vardar chub (Squalius vardarensis) inhabiting mining impacted rivers Zletovska and Kriva, in comparison with chub from the reference Bregalnica River. It was done by use of indicators of tissue damage (histopathology of liver and gonads) and general indicators of exposure to environmental stressors (condition factor, organo-somatic indices and external/internal macroscopic lesions). Histological assessment of gonads revealed good reproductive health in all three rivers, indicating high tolerance of gonads to contaminant exposure. Contrary, several external/internal lesions were more pronounced in chub from severely metal contaminated Zletovska River. Prevalence of hepatic lesions was also higher in mining impacted rivers (in Kriva, 70%; in Zletovska, 59%) compared to Bregalnica River (38%). The spectrum of histological lesions observed in chub liver varied from non-specific minor degenerative conditions, such as lymphocyte infiltration, fibrosis, parasites, granulomas and lipidosis, to extensive and/or more severe changes such as bile duct proliferation, necrosis, megalocytosis, light-dark hepatocytes and hepatocytes regeneration. The results of histopathological investigation for all three rivers showed clear signs of water contamination, especially prominent in mining influenced rivers. More research efforts should be devoted to study of environmental conditions and metal contamination in the mining impacted rivers worldwide, especially of their effects on health of local ichthyofauna. PMID:26986024

  12. Dissociation Energies of Diatomic Molecules

    Institute of Scientific and Technical Information of China (English)

    FAN Qun-Chao; SUN Wei-Guo

    2008-01-01

    Molecular dissociation energies of 10 electronic states of alkali molecules of KH, 7LID, 7LiH, 6LiH, 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 Detheory, which are in excellent agreement with the experimental dissociation energies Dexpte.

  13. CO dissociation on Ni: The effect of steps and of nickel carbonyl

    DEFF Research Database (Denmark)

    Engbæk, Jakob; Lytken, Ole; Nielsen, Jane Hvolbæk;

    2008-01-01

    The dissociation of CO was investigated on a stepped Ni(141313) crystal. The experiments show that the monoatomic steps completely dominate the dissociation of CO on the nickel surface. The activation energy for dissociation of CO along the steps is measured at 500 K to be 150 kJ/mol in the press...

  14. A direct, local model of dissociative recombination of HF+

    International Nuclear Information System (INIS)

    The direct mechanism of dissociative recombination of HF+ have been studied by propagating wave packets on 30 resonant states. The relevant electronic states have been calculated ab initio with electron scattering calculations and multireference configuration interaction calculations. We obtain a qualitative good agreement with experiments for energies in the range from 0.04 eV to 10 eV. Some of the structures in the experimental cross section can be explained by the direct capture and dissociation along the resonant states. To fully describe the measured cross section, the electronic couplings between the neutral states cannot be neglected.

  15. Laser capture.

    Science.gov (United States)

    Potter, S Steven; Brunskill, Eric W

    2012-01-01

    This chapter describes detailed methods used for laser capture microdissection (LCM) of discrete subpopulations of cells. Topics covered include preparing tissue blocks, cryostat sectioning, processing slides, performing the LCM, and purification of RNA from LCM samples. Notes describe the fine points of each operation, which can often mean the difference between success and failure. PMID:22639264

  16. On the formation of OH ordered layers by dissociation of H 2O on an oxygen covered Ag(1 1 0) surface: An STM investigation

    Science.gov (United States)

    Guillemot, L.; Bobrov, K.

    2007-02-01

    We present results of an STM investigation of water interaction with an oxygen covered Ag(1 1 0) on the example of the O(4 × 1) reconstructed surface. In agreement with numerous previous experimental works, using diffraction techniques, we found that a structure of OH(1 × 2) type, displaying rows in the [1 -1 0] direction, is formed. The new features revealed by this local probe study, is the presence of quasi rectangular islands evenly distributed across the terraces, with a density of 0.22 ± 0.03 and a mean area of 90 ± 15 nm 2 at 220 K. They are imaged at an apparent height of 0.14 nm. It is remarkable that the same OH row structure is present on the whole terrace "on top" and "in between" the islands. These features are attributed to silver islands of mono-atomic height, formed by clustering of silver ad-atoms released during reaction of the O atoms with the water molecules. These findings point to a more complex behaviour of the reaction dynamics than previously described. They emphasise the key role of the silver ad-atoms, present in the added rows of the initial Ag(1 1 0)-O(4 × 1) surface, in the formation of the nanostructures. In turn it is concluded that the rows evidenced by this STM and previous diffraction studies, are formed by OH chains.

  17. Spectroscopic Investigation of H Atom Transfer in a Gas-phase Dissociation Reaction: McLafferty Rearrangement of Model Gas-phase Peptide Ions

    Energy Technology Data Exchange (ETDEWEB)

    Michael J. Van Stipdonk; Dale R. Kersetter; Christopher M. Leavitt; Gary S. Groenewold; Jeffrey Steill; Jos Oomens

    2008-07-01

    Wavelength-selective infrared multiple-photon photodissociation (WS-IRMPD) was used to study isotopically-labeled ions generated by McLafferty rearrangement of nicotinyl-glycine-tert-butyl ester and betaine-glycine-tert-butyl ester. The tert-butyl esters were incubated in a mixture of D2O and CH3OD to induce solution-phase hydrogen-deuterium exchange and then converted to gas-phase ions using electrospray ionization. McLafferty rearrangement was used to generate the free-acid forms of the respective model peptides through transfer of an H atom and elimination of butene. The specific aim was to use vibrational spectra generated by WS-IRMPD technique to determine whether the H atom remains at the acid group, or migrates to one or more of the other exchangeable sites. Comparison of the IRMPD results in the region from 1200-1900 cm-1 to theoretical spectra for different isotopically-labeled isomers clearly shows that the H atom is situated at the C-terminal acid group and migration to amide positions is negligible on the time scale of the experiment. The results of this study suggest that use of the McLafferty rearrangement for peptide esters could be an effective approach for generation of H-atom isotope tracers, in-situ, for subsequent investigation of intra-molecular proton migration during peptide fragmentation studies.

  18. Spectroscopic Investigation of H Atom Transfer in a Gas-phase Dissociation Reaction: McLafferty Rearrangement of Model Gas-phase Peptide Ions

    International Nuclear Information System (INIS)

    Wavelength-selective infrared multiple-photon photodissociation (WS-IRMPD) was used to study isotopically-labeled ions generated by McLafferty rearrangement of nicotinyl-glycine-tert-butyl ester and betaine-glycine-tert-butyl ester. The tert-butyl esters were incubated in a mixture of D2O and CH3OD to induce solution-phase hydrogen-deuterium exchange and then converted to gas-phase ions using electrospray ionization. McLafferty rearrangement was used to generate the free-acid forms of the respective model peptides through transfer of an H atom and elimination of butene. The specific aim was to use vibrational spectra generated by WS-IRMPD technique to determine whether the H atom remains at the acid group, or migrates to one or more of the other exchangeable sites. Comparison of the IRMPD results in the region from 1200-1900 cm-1 to theoretical spectra for different isotopically-labeled isomers clearly shows that the H atom is situated at the C-terminal acid group and migration to amide positions is negligible on the time scale of the experiment. The results of this study suggest that use of the McLafferty rearrangement for peptide esters could be an effective approach for generation of H-atom isotope tracers, in-situ, for subsequent investigation of intra-molecular proton migration during peptide fragmentation studies

  19. 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. PMID:26211678

  20. Steering a molecule into dissociation via vibrational excitation

    Energy Technology Data Exchange (ETDEWEB)

    Kaestner, Alexander; Grossmann, Frank; Krause, Sebastian; Schmidt, Ruediger [Institut fuer Theoretische Physik, Technische Universitaet Dresden, 01062 Dresden (Germany); Kenfack, Anatole [Physikalische und Theoretische Chemie, Institut fuer Chemie und Biochemie, Freie Universitaet Berlin, Takustr. 3, 14195 Berlin (Germany); Rost, Jan-Michael [Max Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, 01187 Dresden (Germany)], E-mail: frank@physik.tu-dresden.de

    2009-08-15

    For a laser driven molecule, we show that the ionization and the dissociation channels can be separated by preparing the molecule in a specific vibrational state. Specifically, we investigate the dynamics of the hydrogen molecular ion under a femtosecond infrared laser field aligned with the molecular axis. We find dissociation probabilities of more than 60%, considerably higher than reported so far. We demonstrate that a full dimensional description of the electron dynamics is necessary to obtain accurate results for the combined ionization/dissociation dynamics.

  1. Steering a molecule into dissociation via vibrational excitation

    International Nuclear Information System (INIS)

    For a laser driven molecule, we show that the ionization and the dissociation channels can be separated by preparing the molecule in a specific vibrational state. Specifically, we investigate the dynamics of the hydrogen molecular ion under a femtosecond infrared laser field aligned with the molecular axis. We find dissociation probabilities of more than 60%, considerably higher than reported so far. We demonstrate that a full dimensional description of the electron dynamics is necessary to obtain accurate results for the combined ionization/dissociation dynamics.

  2. Charmonium dissociation by mesons in heavy-ion collisions

    OpenAIRE

    Lykasov, Gennady I.; Cassing, Wolfgang

    2006-01-01

    The charmonium dissociation by mesons in relativistic heavy-ion reactions is analyzed within the Regge approach. It is shown that the inclusion of the initial and final state interactions in the dissociation of J/Psi to bar{D}* D* close to threshold increases the cross section significantly and can not be neglected in comparison to the total dissociation rate. This is due to resonant bar{D}*-D* interactions in sqrt{s} close to the masses of the Psi(4.04) and Psi(4.16) mesons. We also investig...

  3. Investigation of CO2 capture in fluid catalytic cracking process%催化裂化实现CO2捕集的技术探讨

    Institute of Scientific and Technical Information of China (English)

    李秋芝; 陈曼桥; 孟凡东; 王龙延

    2012-01-01

    论述了4种碳捕集方法,即燃烧前捕集、氧燃烧捕集、燃烧后捕集和化学链燃烧捕集,得出氧燃烧捕集是比较适合于催化裂化实现CO2捕集的技术.同时,讨论了氧燃烧对再生器效率、旋风分离器效率以及取热器负荷的影响.%Four methods of carbon capture and sequestration are described in this study, including pre-combustion capture, post-combustion capture, oxy-fuel combustion capture and chemical looping combustion capture. Among all of these methods, it is concluded that oxy-fuel combustion capture is a suitable method for fluid-catalytic-cracking CO2 capture. Furthermore, the effect of oxy-fuel combustion on the effectiveness of regenerator and cyclone separator, and the load of catalyst cooler are discussed.

  4. 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.

  5. 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

  6. Dissociation pressure of polonium dioxide

    International Nuclear Information System (INIS)

    Information on determining the temperature dependence of the vapour pressure during polonium-210 dissociation is given. To determine the vapour pressure of polonium during PoO2 dissociation, the method based on remote measuring the amount of the vapour of the radioactive element by its own radiation in a known volume with dynamic equilibrium inside an ampoule evacuated to 10-2 Torr has been used. The vapour pressure of P0 in vacuum within the temperature range from 530 to 595 deg C obeys the equation lg Psub(mm)=19.4440+-0.7140-(16920+-50O)/T. The polonium evaporation heat during PoO2 dissociation is 77.4+-2.3 kcal/mol. Enthalpy of PoO2 dissociation is 154.8 kcal/mol

  7. An Investigation into Automatically Captured Autobiographical Metadata, and the Support for Autobiographical Narrative Generation. Mini-Thesis: PhD upgrade report

    OpenAIRE

    Tuffield, Mischa M; Millard, David E.; Shadbolt, Nigel R.

    2006-01-01

    Personal information and the act of publishing multimedia artifacts to the World Wide Web is becoming more and more observable. This report presents an infrastructure for the capturing and exploitation of personal metadata to drive research into context aware systems. I aim to expose ongoing research in the areas of capture of personal experiences, context aware systems, multimedia annotation systems, narrative generation, and that of Semantic Web enabling technologies. This report details th...

  8. 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 prov...... large-scale phosphoproteome analysis alongside collisional induced dissociation, (CID) and electron capture/transfer dissociation (ECD/ETD)....

  9. Shattering dissociation in high-energy molecular collisions between nitrate esters

    Science.gov (United States)

    Schweigert, Igor V.; Dunlap, Brett I.

    2011-09-01

    We present ab initio molecular dynamics simulations of head-on collisions between ethyl nitrate molecules at collisional energies from 200 to 1200 kJ/mol. Above a threshold energy, an increasing fraction of the collisions led to rapid dissociation on impact—"shattering." The probability of the shattering dissociation was derived from the quasiclassical trajectories sampling the initial vibrational motion at Tvib = 300 K. Even for the zero impact parameter and a fixed orientation considered, the observed dissociation probability exhibited a wide spread (much larger than kTvib) as a function of the collision energy. This is attributed to variations in the initial vibrational phase. We propose a closed-form expression for the energy-dependent dissociation probability that captures the dependence on the phase and use it to analyze the probability of the shattering dissociation of a larger nitrate ester, pentaerythritol tetranitrate.

  10. Dissociative experiences and dissociative minds: Exploring a nomological network of dissociative functioning.

    Science.gov (United States)

    Schimmenti, Adriano

    2016-01-01

    In this study, the psychometric properties of the Dissociative Experiences Scale-II (DES-II) were tested in a sample of Italian adults, and a nomological network of dissociative functioning based on current psychodynamic research was examined. A total of 794 participants (55% females) ranging in age from 18 to 64 completed the DES-II and other measures of theory of mind, alexithymia, attachment style, and empathy. The Italian translation of the DES-II showed high internal consistency, adequate item-to-scale homogeneity, and good split-half reliability. A single-factor solution including the 8 items of pathological dissociation (DES-T) adequately fit the data. Participants who reported higher levels of dissociative experiences showed significantly lower scores on theory of mind and empathy than other participants. They also showed significantly higher scores on alexithymia, preoccupied attachment, and fearful attachment. Results of the study support the view that people who suffer from severe dissociative experiences may also have difficulties mentalizing and regulating affects and that they may feel uncomfortable in close relationships because they have a negative view of the self. This can inform clinical work with dissociative individuals, who could benefit from therapies that consider their potential problems with mentalization, empathy, affect regulation, and attachment. PMID:26507547

  11. Unusual dissociative adsorption of H2 over stoichiometric MgO thin film supported on molybdenum

    Science.gov (United States)

    Song, Zhenjun; Xu, Hu

    2016-03-01

    The dissociation of a hydrogen molecule on perfect MgO(0 0 1) films deposited on Mo(0 0 1) surface is investigated systematically using periodic density-functional theory (DFT) method. The unusual adsorption behavior of heterolytic dissociative hydrogen molecule at neighboring surface oxygen and surface magnesium, is clarified here. To our knowledge, this heterolytic dissociative state has never been found before on bulk MgO(0 0 1) or metal supported perfect MgO(0 0 1) surfaces (without low coordination sites). The results confirm that, in all cases, the heterolytic dissociation is much more favorable that homolytic dissociation both energetically and kinetically. The energy differences between two dissociative states are very large, in the range of 1.1 eV-1.5 eV for Mo supported 1 ML-3 ML oxide films, which inhibits, to a great extent, the homolytic dissociation in the respect of reaction thermodynamics. The energy barriers of heterolytic dissociation are about 0.5 eV, much lower that the barrier of homolytic dissociation. The transformation reaction on thick films will be more endothermic. Passing through heterolytic dissociation state has significantly lowered the reaction heat and the energy barrier for obtaining homolytic dissociative structure, which makes the homolytic splitting of H2 easier on 2 ML oxide films. The results provide a useful strategy for enhancing the reactivity of the nonreducible metal oxide.

  12. Theoretical investigation on the bond dissociation enthalpies of phenolic compounds extracted from Artocarpus altilis using ONIOM(ROB3LYP/6-311++G(2df,2p):PM6) method

    Science.gov (United States)

    Thong, Nguyen Minh; Duong, Tran; Pham, Linh Thuy; Nam, Pham Cam

    2014-10-01

    Theoretical calculations have been performed to predict the antioxidant property of phenolic compounds extracted from Artocarpus altilis. The Osbnd H bond dissociation enthalpy (BDE), ionization energy (IE), and proton dissociation enthalpy (PDE) of the phenolic compounds have been computed. The ONIOM(ROB3LYP/6-311++G(2df,2p):PM6) method is able to provide reliable evaluation for the BDE(Osbnd H) in phenolic compounds. An important property of antioxidants is determined via the BDE(Osbnd H) of those compounds extracted from A. altilis. Based on the BDE(Osbnd H), compound 12 is considered as a potential antioxidant with the estimated BDE value of 77.3 kcal/mol in the gas phase.

  13. Investigation for the puzzling abundance pattern of the neutron-capture elements in the ultra metal-poor star: CS 30322-023

    CERN Document Server

    Cui, W Y; Ma, K; Zhang, L

    2007-01-01

    The s-enhanced and very metal-poor star CS 30322-023 shows a puzzling abundance pattern of the neutron-capture elements, i.e. several neutron-capture elements such as Ba, Pb etc. show enhancement, but other neutron-capture elements such as Sr, Eu etc. exhibit deficient with respect to iron. The study to this sample star could make people gain a better understanding of s- and r-process nucleosynthesis at low metallicity. Using a parametric model, we find that the abundance pattern of the neutron-capture elements could be best explained by a star that was polluted by an AGB star and the CS 30322-023 binary system formed in a molecular cloud which had never been polluted by r-process material. The lack of r-process material also indicates that the AGB companion cannot have undergone a type-1.5 supernova, and thus must have had an initial mass below 4.0M$_\\odot$, while the strong N overabundance and the absence of a strong C overabundance indicate that the companion's initial mass was larger than 2.0M$_\\odot$. Th...

  14. Pesquisa de Trichinella spiralis em roedores capturados na zona portuária de Santos An investigation of Trichinella spiralis in rodents captured in the Santos dock area

    Directory of Open Access Journals (Sweden)

    Gil Vianna Paim

    1979-03-01

    Full Text Available Examinaram-se 594 diafragmas de roedores capturados na zona portuária de Santos tendo em vista a procura de larvas de Trichinella spiralis. Todos os diafragmas examinados estavam negativos.Five hundred and ninety-four diaphragms of rodents captured in the Santos dock area were examined for Trichinella spiralis. The results of the examinations were negative.

  15. Differences in brain 5-HT transporter dissociation rates among animal species

    Energy Technology Data Exchange (ETDEWEB)

    Erreboe, I.; Plenge, P.; Mellerup, E.T. [Univ. of Copenhagen, Dept. of Pharmacology, Lab. of Neuropsychiatry, Copenhagen (Denmark)

    1995-06-01

    The potential of using receptor-ligand dissociation rates as a model for investigating molecular changes in receptors was tested using the dissociation of [{sup 3}H]citalopram, [{sup 3}H]paroxetine and [{sup 3}H]imipramine from the brain 5-HT transporter of four different species (mouse, rat, pig and man). Since the dissociation rates of each of the three ligands differed in most of the species investigated, receptor-ligand dissociation rate constants would seem to be a sensitive measure of receptor conformation. The model could be useful in the search of structural variation in receptors whether attributable to genetic factors or to posttranslational modification. (au) (12 refs.).

  16. Dissociation of deuteron, 6He and 11Be from Coulomb dissociation reaction cross-section

    Indian Academy of Sciences (India)

    Ramendra Nath Majumdar

    2008-05-01

    The fragmentation of deuteron, 6He and 11Be have been studied during interaction with the 208Pb nucleus at various projectile energies. The Coulomb dissociation cross-sections and the momentum distribution of the break-up fragments have been analysed within the framework of the direct fragmentation model. The post-acceleration effect of deuteron during break-up and the halo structures of both the 6He and 11Be have been investigated.

  17. Study of SI engine fueled with methanol vapor and dissociation gas based on exhaust heat dissociating methanol

    International Nuclear Information System (INIS)

    Highlights: • The full load power decreases successively from gasoline engine, methanol vapor engine to dissociated methanol engine. • Both power and thermal efficiency of dissociated methanol engine can be improved by boosting pressure. • The conversion efficiency of recovered exhaust gas energy is largely influenced by the BMEP. • At the same BMEP, dissociated methanol engine has higher thermal efficiency than methanol vapor engine and gasoline engine. - Abstract: To improve the fuel efficiency of internal combustion (IC) engine and also achieve the goal of direct usage of methanol fuel on IC engine, an approach of exhaust heat dissociating methanol was investigated, which is a kind of method for IC engine exhaust heat recovery (EHR). A bottom cycle system is coupled with the IC engine exhaust system, which uses the exhaust heat to evaporate and dissociate methanol in its catalytic cracker. The methanol dissociation gas (including methanol vapor) is used as the fuel for IC engine. This approach was applied to both naturally aspirated (NA) engine and turbocharged engine, and the engine performance parameters were predicted by the software GT-power under various kinds of operating conditions. The improvement to IC engine performance and the conversion efficiency of recovered exhaust gas energy can be evaluated by comparing the performances of IC engine fueled with various kinds of fuels (or their compositions). Results show that, from gasoline engine, methanol vapor engine to dissociated methanol engine, the full load power decreases successively in the entire speed area due to the declining of volumetric efficiency, while it is contrary in the thermal efficiency at the same brake mean effective pressure (BMEP) level because of the improving of fuel heating value. With the increase of BMEP, the conversion efficiency of recovered exhaust gas energy is promoted. All those results indicate that the approach of exhaust heat dissociating methanol has large

  18. 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...

  19. Molecular Dissociation Induced by Electron Collisions

    Science.gov (United States)

    Wolf, Andreas

    2009-05-01

    Free electrons can efficiently break molecules or molecular ions in low-energy collisions by the processes of dissociative recombination or attachment. These processes make slow electrons efficient chemical agents in many environments. For dissociative recombination, in particular, studies of the underlying reaction paths and mechanisms have become possible on a uniquely elementary level in recent years both for theory and experiment. On the experimental side, collisions can be prepared at resolved collision energies down to the meV (10 Kelvin) level, increasingly gaining control also over the initial molecular quantum level, and individual events are detected and kinematically analyzed by fast-beam coincidence fragment imaging. Experiments are reported from the ion cooler ring TSR in Heidelberg. Stored beams of molecular ions cooled in their external and internal degrees of freedom are collinearly merged with intense and cold electron beams from cryogenic GaAs photocathodes, recently shown to yield fast cooling of the center-of-mass motion also for heavy and correspondingly slow molecular ion beams. To reconstruct the molecular fragmentation events multiparticle imaging can now be used systematically with collision energies set a wide range, especially aiming at specific electron capture resonances. Thus, for CF^+ it is found that the electronic state of the C fragment (^3P or ^1D) switches resonantly when the collision energy is changed by only a small fraction. As a new powerful tool, an energy-sensitive multi-strip surface-barrier detector (EMU) has been set up to measure with near-unity efficiency the masses of all fragments together with their hit positions in high-multiplicity events. Among many uses, this device allows internal molecular excitations to be derived for individual chemical channels in polyatomic fragmentation. New results will be presented in particular on the breakup of the hydronium ion (D3O^+).

  20. 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

  1. [Gender differences in dissociative disorders].

    Science.gov (United States)

    Spitzer, C; Freyberger, H J

    2008-01-01

    The relationship between mental illness, on the one hand, and sex and gender, on the other hand, has received interest since the beginning of medicine in antique times. A prototypical example of a seemingly woman-specific disease is hysteria. The term itself, which is derived from the Greek word for womb, denotes a psychosexual dimension comprising the current attitude towards sexuality and the dominating gender relationship. In addition, the colourful history of hysteria indicates that illness is not exclusively determined by biological factors, but also significantly by socio-cultural influences, for example in the treatment of hysterical women. Even nowadays, there is a wide-spread belief that dissociative symptoms and disorders, which have succeeded hysteria in current classification systems, are predominantly seen in women. However, empirical studies in the general population and in different clinical samples using sound instruments have indicated that dissociative symptoms do not differ between the genders. The seemingly dominance of dissociative disorders in women may also depend on the socio-cultural context, because men with dissociative disorders usually do not enter the general health system, but rather the legal system, i.e. they can be found in jail or forensic institutions. PMID:18185968

  2. The regenerating mechanisms of high-lithium contend zirconates as CO2 capture sorbents: Experimental measurements and theoretical investigations

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Yuhua [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Leske, Jonathan [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); URS Corp., Charlotte, NC (United States)

    2015-08-12

    By combining TGA and XRD measurements with theoretical calculations of the capture of CO2 by lithium-rich zirconates (Li8ZrO6 and Li6Zr2O7), it has been demonstrated that the primary regeneration product during absorption/desorption cycling is in the form of Li2ZrO3. During absorption/desorption cycles, lithium-rich zirconates will be consumed and will not be regenerated. Results indicate that among known lithium zirconates, Li2ZrO3 is the best sorbent for CO2 capture.

  3. Experimental investigations of electron capture from atomic hydrogen and deuterium by alpha particles. Annual report, 1 October 1984-30 September 1985

    International Nuclear Information System (INIS)

    The major effort of this past year has been spent in designing and building the resistor assemblies and controls necessary to modify the UMR ion energy-loss spectrometer for studies of the type described in our original proposal. Specifically, we are interested in the collision He++ + H → He+(n) + H+ and measurement of the total capture cross section as a function of n for He++ energies between 25 and 200 keV

  4. Dissociating Prediction Failure: Considerations from Music Perception

    DEFF Research Database (Denmark)

    Ross, Suzi; Hansen, Niels Christian

    2016-01-01

    Dissociating Prediction Failure: Considerations from Music Perception The Journal of Neuroscience, 16 March 2016, 36(11): 3103-3105;......Dissociating Prediction Failure: Considerations from Music Perception The Journal of Neuroscience, 16 March 2016, 36(11): 3103-3105;...

  5. Dissociative experiences in obsessive-compulsive disorder and trichotillomania: clinical and genetic findings.

    Science.gov (United States)

    Lochner, Christine; Seedat, Soraya; Hemmings, Sian M J; Kinnear, Craig J; Corfield, Valerie A; Niehaus, Dana J H; Moolman-Smook, Johanna C; Stein, Dan J

    2004-01-01

    A link between dissociation proneness in adulthood and self-reports of childhood traumatic events (including familial loss in childhood, sexual/physical abuse and neglect) has been documented. Several studies have also provided evidence for an association between dissociative experiences and trauma in patients with various psychiatric disorders, including post-traumatic stress disorder, borderline personality, dissociative identity and eating disorders. Based on the relative paucity of data on dissociation and trauma in obsessive-compulsive disorder (OCD) and trichotillomania (TTM), the primary objective of this study was to examine the relationship between trauma and dissociative experiences (DE) in these two diagnostic groups. Furthermore, the availability of clinical and genetic data on this sample allowed us to explore clinical and genetic factors relevant to this association. A total of 110 OCD and 32 TTM patients were compared with respect to the degree of dissociation (using the Dissociative Experiences Scale [DES]) and childhood trauma (using the Childhood Trauma Questionnaire [CTQ]). Patients were classified on the DES as either "high" (mean DES score >/= 30) or "low" (mean DES score sexual abuse, and physical neglect. In the OCD group, high dissociators were significantly younger than low dissociators, and significantly more high dissociators than low dissociators reported a lifetime (current and past) history of tics (P disorder (P =.027). In the TTM group, significantly more high dissociators than low dissociators reported (lifetime) kleptomania (P =.005) and depersonalisation disorder (P =.005). In the Caucasian OCD patients (n = 114), investigation of genetic polymorphisms involved in monoamine function revealed no significant differences between high and low dissociator groups. This study demonstrates a link between childhood trauma and DE in patients with OCD and TTM. High dissociative symptomatology may be present in a substantial proportion of

  6. Predicting three types of dissociation in female survivors of intimate partner violence.

    Science.gov (United States)

    Fleming, C J Eubanks; Resick, Patricia A

    2016-01-01

    Previous research suggests that studying the effect of dissociation is particularly important in survivors of intimate partner violence because of the risk of revictimization. The current study investigated demographic variables, child and current abuse characteristics, coping style, and cognitive distortions as predictors of peritraumatic, trait, and posttraumatic stress disorder (PTSD)-related dissociation in a sample of female intimate partner violence survivors. The sample consisted of 372 women, the majority African American, with an average age of 34.41 years (SD = 8.09). Peritraumatic dissociation was significantly predicted by child physical abuse, current abuse injury, cognitive distortions about safety, and problem disengagement coping. Trait dissociation was significantly predicted by minority race, personal income, and cognitive distortions about safety and self-worth. PTSD-related dissociation was significantly predicted by cognitive distortions about self-worth, problem and emotion disengagement coping, and peritraumatic dissociation. In the models predicting both trait and PTSD-related dissociation, abuse characteristics significantly predicted dissociation until the entry of cognitive variables into the model. The analysis indicated a significant indirect effect of cognitive distortions on the relationship between current sexual aggression and trait dissociation. Results also suggested that there were indirect effects of both cognitive distortions and peritraumatic dissociation on the relationships between current psychological abuse/injury and PTSD-related dissociation. Findings point to the importance of cognitions in the development and maintenance of dissociation and suggest that treatments designed to help clients accept and process traumatic events may help reduce dissociation and in turn prevent future revictimization. PMID:26274868

  7. Correlations in the hadronic double diffractive dissociation

    International Nuclear Information System (INIS)

    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

  8. The relationship of problematic internet use with dissociation among South Korean internet users.

    Science.gov (United States)

    Lee, Tae Kyung; Roh, Sungwon; Han, Joo Hyun; Park, Se Jin; Soh, Min A; Han, Doug Hyun; Shaffer, Howard J

    2016-07-30

    This study examined patterns of problematic internet use (PIU) among South Korean internet users to investigate the association between PIU and dissociative experiences. Five hundred and eight participants between 20 and 49 years old were recruited through an online panel survey. Using logistic regression analysis with PIU as the dependent variable, we observed that the participants with PIU were more likely to have alcohol-related behaviors or problems, higher levels of perceived stress, and dissociative experiences. Participants' scores on the Korean version of the Dissociative Experiences Scale were positively correlated with the severity of PIU. Individuals with PIU and dissociation had more severe PIU and more severe mental-health problems than those with PIU but without dissociation. These findings suggest that treatment programs for persons with PIU should focus on helping them tolerate negative affect and increase their level of awareness to prevent the occurrence of dissociative experiences. PMID:27156026

  9. Ion Mobility Spectrometry Reveals Duplex DNA Dissociation Intermediates

    Science.gov (United States)

    Burmistrova, Anastasia; Gabelica, Valérie; Duwez, Anne-Sophie; De Pauw, Edwin

    2013-11-01

    Electrospray ionization (ESI) soft desolvation is widely used to investigate fragile species such as nucleic acids. Tandem mass spectrometry (MS/MS) gives access to the gas phase energetics of the intermolecular interactions in the absence of solvent, by following the dissociation of mass-selected ions. Ion mobility mass spectrometry (IMS) provides indications on the tridimensional oligonucleotide structure by attributing a collision cross section (CCS) to the studied ion. Electrosprayed duplexes longer than eight bases pairs retain their helical structure in a solvent-free environment. However, the question of conformational changes under activation in MS/MS studies remains open. The objective of this study is to probe binding energetics and characterize the unfolding steps occurring prior to oligonucleotide duplex dissociation. Comparing the evolution of CCS with collision energy and breakdown curves, we characterize dissociation pathways involved in CID-activated DNA duplex separation into single strands, and we demonstrate here the existence of stable dissociation intermediates. At fixed duplex length, dissociation pathways were found to depend on the percentage of GC base pairs and on their position in the duplex. Our results show that pure GC sequences undergo a gradual compaction until reaching the dissociation intermediate: A-helix. Mixed AT-GC sequences were found to present at least two conformers: a classic B-helix and an extended structure where the GC tract is a B-helix and the AT tract(s) fray. The dissociation in single strands takes place from both conformers when the AT base pairs are enclosed between two GC tracts or only from the extended conformer when the AT tract is situated at the end(s) of the sequence.

  10. Dissociation of H2 on carbon doped aluminum cluster Al6C

    International Nuclear Information System (INIS)

    The dissociation of H2 molecule is the first step for chemical storage of hydrogen, and the energy barrier of the dissociation is the key factor to decide the kinetics of the regeneration of the storage material. As a light element, aluminum is an important candidate component for storage materials with high gravimetric density. This paper investigates the adsorption and dissociation of H2 on carbon doping aluminum cluster Al6C. The study shows that doping carbon into aluminum cluster can significantly change the electronic structure and increase the stability. Al6C has a few stable isomers with close energies and their structures are quite flexible. The molecular adsorption of H2 on Al6C is very weak, but the H2 molecule can be dissociated easily on this cluster. The stable product of the dissociated adsorption is searched and the different paths for the dissociation are investigated. During the dissociation of H2, the structure of the cluster adjusts accordingly, and strong orbital interaction between the hydrogen and the cluster occurs. The calculated energy barrier for the dissociation is only 0.30 eV, which means the dissociation can take place at moderate temperatures

  11. Electron capture and stellar collapse

    International Nuclear Information System (INIS)

    In order, to investigate the function of electron capture in the phenomenon of pre-supernovae gravitacional collapse, an hydrodynamic caculation was carried out, coupling capture, decay and nuclear reaction equation system. A star simplified model (homogeneous model) was adopted using fermi ideal gas approximation for tthe sea of free electrons and neutrons. The non simplified treatment from quasi-static evolution to collapse is presented. The capture and beta decay rates, as wellas neutron delayed emission, were calculated by beta decay crude theory, while the other reaction rates were determined by usual theories. The preliminary results are presented. (M.C.K.)

  12. Dissociation of ozonide in water

    Energy Technology Data Exchange (ETDEWEB)

    Bentley, J.; Collins, J.Y.; Chipman, D.M.

    2000-05-18

    The free energy of bond dissociation for ozonide ion radical is found to be lowered in aqueous solution by about 20 kcal/mol relative to that in the gas phase, based on electronic structure calculations. Explicit treatment of anion-water clusters indicates that the stronger hydrogen bonds to first-shell water molecules formed by O{sup {minus}} relative to O{sub 3}{sup {minus}} account for much of the lowering. Reaction field methods show that nonspecific electrostatic polarization of the bulk solvent further contributes noticeably to the lowering. The study clearly demonstrates that the aqueous free energy of ozonide bond dissociation is small, and probably endothermic. The best semitheoretical prediction of the actual value is 5 {+-} 5 kcal/mol.

  13. [Prison psychosis and dissociative disorders].

    Science.gov (United States)

    al Chaabani, S; Bataille, M

    2002-12-01

    Through a few clinical case histories stemming from their daily activities at the psychiatric section of the Lantin Prison, the authors propose to revisit the classic concept of Prison psychosis. They broaden its limits to include other psychotic and dissociative phenomena common to the jail population. This requires a strict differential diagnosis, allowing to eliminate some similar pathologies; nevertheless, some difficulties and imperfections persist. The development of the psychosis, the input from the jail architecture and milieu, the predisposing as well as facilitating factors linked to the personality of the inmate, and triggering phenomena are discussed. Finally, the comorbidity between these psychotic/dissociative phenomena and the borderline & histrionic personality disorders is envisaged. PMID:12632838

  14. Coulomb dissociation of N,2120

    Science.gov (United States)

    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; Boretzky, Konstanze; Borge, Maria J. G.; Burgunder, G.; Caamaño, Manuel; Caesar, Christoph; Casarejos, Enrique; Catford, Wilton; Cederkäll, Joakim; Chakraborty, S.; Chartier, Marielle; Chulkov, Leonid; Cortina-Gil, Dolores; Crespo, Raquel; Datta Pramanik, Ushasi; 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; Gernhäuser, Roman; Göbel, Kathrin; Golubev, Pavel; Gonzalez Diaz, D.; Hagdahl, Julius; Heftrich, Tanja; Heil, Michael; Heine, Marcel; Heinz, Andreas; Henriques, Ana; Holl, Matthias; Ickert, G.; Ignatov, Alexander; Jakobsson, Bo; Johansson, Hâkan; Jonson, Björn; Kalantar-Nayestanaki, Nasser; Kanungo, Rituparna; Kelic-Heil, Aleksandra; Knöbel, Ronja; Kröll, Thorsten; Krücken, Reiner; Kurcewicz, J.; Kurz, Nikolaus; Labiche, Marc; Langer, Christoph; Le Bleis, Tudi; Lemmon, Roy; Lepyoshkina, Olga; Lindberg, Simon; Machado, Jorge; Marganiec, Justyna; Mostazo Caro, Magdalena; Movsesyan, Alina; Najafi, Mohammad Ali; Nilsson, Thomas; Nociforo, Chiara; Panin, Valerii; Paschalis, Stefanos; Perea, Angel; Petri, Marina; Pietri, S.; Plag, Ralf; Prochazka, A.; Rahaman, Md. Anisur; Rastrepina, Ganna; Reifarth, Rene; Ribeiro, Guillermo; Ricciardi, M. Valentina; Rigollet, Catherine; Riisager, Karsten; Rossi, Dominic; Sanchez del Rio Saez, Jose; Savran, Deniz; Scheit, Heiko; Simon, Haik; Sorlin, Olivier; Stoica, V.; Streicher, Branislav; Taylor, Jon; Tengblad, Olof; Terashima, Satoru; Thies, Ronja; Togano, Yasuhiro; Uberseder, Ethan; Van de Walle, J.; Velho, Paulo; Volkov, Vasily; Wagner, Andreas; Wamers, Felix; Weick, Helmut; Weigand, Mario; Wheldon, Carl; Wilson, G.; Wimmer, Christine; Winfield, J. S.; Woods, Philip; Yakorev, Dmitry; Zhukov, Mikhail; Zilges, Andreas; Zuber, Kai; R3B Collaboration

    2016-06-01

    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,2120 are reported. Relativistic N,2120 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 19N (n ,γ )20N and 20N (n ,γ ) 21N excitation functions and thermonuclear reaction rates have been determined. The 19 (n ,γ )20N rate is up to a factor of 5 higher at T <1 GK with respect to previous theoretical calculations, leading to a 10% decrease in the predicted fluorine abundance.

  15. Tissue Dissociation for Metastasis Studies.

    Science.gov (United States)

    Kabeer, Farhia; Podsypanina, Katrina

    2016-01-01

    The main requirement for most metastasis-related applications is the conversion of solid tissue into a single-cell suspension. In theory, this suspension represents the diversity of cells present in the tissue, whether malignant or benign. We have found that cell viability, as measured by trypan blue staining or fluorescence-activated cell sorting (FACS), is critical for evaluating the success of the tissue-dissociation procedure. The recommended goal is at least 70% cell viability. PMID:26832679

  16. Direct Capture at Low Energies

    OpenAIRE

    Balogh, W.; Bieber, R.; Oberhummer, H.; Rauscher, T.; Kratz, K.-L.; Mohr, P; Staudt, G.; Sharma, M. M.

    1994-01-01

    The importance of direct capture for (n,$\\gamma$)--reactions on intermediate-- and heavy--mass target nuclei occuring in the s-- and r--process is investigated. It is shown that the direct mechanism is non--negligible for magic and neutron rich target nuclei. For some double magic and neutron rich nuclei in the r--process direct capture is even the dominant reaction mechanism.

  17. Coulomb dissociation of 8B and solar neutrino problem

    International Nuclear Information System (INIS)

    We measured the cross section for Coulomb dissociation of 8B using a radioactive 8B beam of 46.5MeV/u energy with a 208Pb target. The cross section for the 7Be(p,γ)8B capture reaction was deduced at Ecm=0.6-1.7MeV. The extracted astrophysical S17 factors were consistent with the values measured by Vaughn et al. and Filippone et al. Possible corrections due to 7Be excited state population, E1 and M2 contribution, nuclear contribution and post acceleration effects are considered. ((orig.))

  18. Two-temperature models for nitrogen dissociation

    Science.gov (United States)

    da Silva, M. Lino; Guerra, V.; Loureiro, J.

    2007-12-01

    Accurate sets of nitrogen state-resolved dissociation rates have been reduced to two-temperature (translational T and vibrational Tv) dissociation rates. The analysis of such two-temperature dissociation rates shows evidence of two different dissociation behaviors. For Tv 0.3 T dissociation proceeds predominantly form the near-dissociative vibrational levels, with an abrupt change of behavior at Tv = 0.3 T. These two-temperature sets have then been utilized as a benchmark for the comparison against popular multitemperature dissociation models (Park, Hansen, Marrone-Treanor, Hammerling, Losev-Shatalov, Gordiets, Kuznetsov, and Macheret-Fridman). This has allowed verifying the accuracy of each theoretical model, and additionally proposing adequate values for any semi-empirical parameters present in the different theories. The Macheret-Fridman model, who acknowledges the existence of the two aforementioned dissociation regimes, has been found to provide significantly more accurate results than the other models. Although these different theoretical approaches have been tested and validated solely for nitrogen dissociation processes, it is reasonable to expect that the general conclusions of this work, regarding the adequacy of the different dissociation models, could be extended to the description of arbitrary diatomic dissociation processes.

  19. Stability of cadmium complex with octaphenyltetrazaporphin and its solvoprotolytic dissociation in pyridine-acetic acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Berezin, B.D.; Khelevina, O.G. (Ivanovskij Khimiko-Tekhnologicheskij Inst. (USSR))

    1982-01-01

    Solvoprotolytic dissociation of octaphenyltetrazaporphin cadmium complex in acetic acid solutions in pyridine is investigated. It is stated that its dissociation is obeyed submitted the first order by the complex and the second order by solvated proton. Comparison with cadmium complexes of other porphyrins is carried out.

  20. Enhancement of burning velocity by dissociated oxygen atoms

    Science.gov (United States)

    Akashi, Haruaki; Yoshinaga, Tomokazu; Sasaki, Koichi

    2015-09-01

    Green technology, such as preventing global warming, has been developed for years. Researches on plasma assisted combustion is one of the technologies and have been done for investigating more efficient combustion, more efficient use of fossil fuel with plasmas or applying electric fields. In the ignition time delay analyses with the dissociated oxygen atoms which is generated by non-equilibrium plasma had significant effect on the ignition time. In this paper, dissociated oxygen could effect on burning velocity or not has been examined using CHEMKIN. As a result, no effect can be seen with dissociation degree of lower than 10-3. But there is an effect on the enhancement of burning velocity with higher degree of 10-3. At the dissociation degree of 5×10-2, the burning velocity is enhanced at a factor of 1.24. And it is found that the distributions of each species in front of preheat zone are completely different. The combustion process is proceeded several steps in advance, and generation of H2O, CO and CO2 can be seen before combustion in higher dissociation case. This work was supported by KAKENHI (22340170).

  1. Electron-impact dissociation and ionization of NO+ ions

    Science.gov (United States)

    Belic, D. S.; Urbain, X.; Cherkani-Hassani, H.; Defrance, P.

    2016-07-01

    Absolute cross sections for electron-impact ionization and dissociation of NO+ ions are reported. Simple ionization to NO2+ ion and production of singly charged N+ and O+ and doubly charged N2+ and O2+ fragments have been investigated. The animated electron-ion crossed-beam method is applied in the energy range from the respective thresholds up to 2.5 keV. The maximum of the simple ionization cross section is found to be (3.49 ± 0.07) × 10‑17 cm2 at 135 eV. The total cross sections for N+ and O+ fragments at the maximum are found to be (13.9 ± 1.0) × 10‑17 cm2 and (14.0 ± 1.4) × 10‑17 cm2, respectively, both at an energy of 85 eV. By performing careful magnetic field scans of the detected signal, contributions of dissociative excitation and dissociative ionization to N+ and O+ production are determined separately. The cross sections for asymmetric dissociative ionization to N2+ and O2+ are found to be over one order of magnitude smaller. Distributions of the kinetic energy release to the fragments are determined for all dissociation processes.

  2. Photogenerated Exciton Dissociation in Highly Coupled Lead Salt Nanocrystal Assemblies

    KAUST Repository

    Choi, Joshua J.

    2010-05-12

    Internanocrystal coupling induced excitons dissociation in lead salt nanocrystal assemblies is investigated. By combining transient photoluminescence spectroscopy, grazing incidence small-angle X-ray scattering, and time-resolved electric force microscopy, we show that excitons can dissociate, without the aid of an external bias or chemical potential gradient, via tunneling through a potential barrier when the coupling energy is comparable to the exciton binding energy. Our results have important implications for the design of nanocrystal-based optoelectronic devices. © 2010 American Chemical Society.

  3. Dissociation of NO2 in femtosecond intense fields

    Institute of Scientific and Technical Information of China (English)

    ZHU Jingyi; GUO Wei; WANG Yanqiu; WANG Li

    2006-01-01

    Experimental investigations on the dissociation and ionization processes of NO2 in intense fields at wavelengths of 810, 405 and 270 nm, are presented. The ratios of NO~/NO+ are found to be independent of the laser intensity at these three wavelengths, but show strong dependence on the wavelengths. Longer wavelength produces a larger parent-ion yield in comparison with 405 nm. Peak profiles of all the fragment ions clearly show little kinetic energy releasing during the dissociation. Fragment ions are suggested to be produced from dissociation of the field ionized parent ions. Our results indicate that laser pulse wavelengths are the most important parameters in ionization-fragmen- tation process of polyatomic molecules in intense field other than the laser intensity.

  4. 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.

  5. Unusual dissociative adsorption of H2 over stoichiometric MgO thin film supported on molybdenum

    CERN Document Server

    Song, Zhenjun

    2015-01-01

    The dissociation of a hydrogen molecule on MgO(001) films deposited on Mo(001) surface is investigated systematically using periodic density-functional theory method. The unusual adsorption behavior of heterolytic dissociative hydrogen molecule at neighboring surface oxygen and surface magnesium, is clarified here. To my knowledge, this heterolytic dissociative state has never been found before on bulk MgO(001) or metal supported MgO(001) surfaces. The results confirm that, in all cases, the heterolytic dissociation is much more favorable that homolytic dissociation both energetically and kinetically. The energy difference between two dissociative states are very large, in the range of 1.1 eV ~ 1.5 eV for Mo supported 1 ML ~ 3 ML oxide films, which inhibits, to a great extent, the homolytic dissociation in the respect of reaction thermodynamics. The energy barrier of heterolytic dissociation are about 0.5 eV, much lower that the barrier of homolytic dissociation. The transformation reaction on thick films wil...

  6. Development and the fragmented self: longitudinal study of dissociative symptomatology in a nonclinical sample.

    Science.gov (United States)

    Ogawa, J R; Sroufe, L A; Weinfield, N S; Carlson, E A; Egeland, B

    1997-01-01

    Dissociative behaviors and their relation to both the self and self-organization were examined using the developmental psychopathology perspective in a prospective longitudinal study of high-risk children. Participants were 168 young adults (n = 79 females, n = 89 males, age = 18-19 years) considered high-risk for poor developmental outcomes at birth due to poverty. The present study investigated whether trauma, sense of self, quality of early mother-child relationship, temperament, and intelligence were related to dissociative symptomatology measured at four times across 19 years. Findings were (a) age of onset, chronicity and severity of trauma were highly correlated and predicted level of dissociation; (b) both the avoidant and disorganized patterns of attachment were strong predictors of dissociation; (c) dissociation in childhood may be a more normative response to disruption and stress, while dissociation in adolescence and young adulthood may be more indicative of psychopathology; (d) preliminary support was found for a model proposed by G. Liotti that links disorganized attachment, later trauma, and dissociation in adulthood; and (e) strong support was found for N. Waller, F. W. Putnam, and E. B. Carlson's contention that psychopathological dissociation should not be viewed as the top end of a continuum of dissociative symptomatology, but as a separate taxon that represents an extreme deviation from normal development. PMID:9449009

  7. Sulfur Dioxide Capture by Heterogeneous Oxidation on Hydroxylated Manganese Dioxide.

    Science.gov (United States)

    Wu, Haodong; Cai, Weimin; Long, Mingce; Wang, Hairui; Wang, Zhiping; Chen, Chen; Hu, Xiaofang; Yu, Xiaojuan

    2016-06-01

    Here we demonstrate that sulfur dioxide (SO2) is efficiently captured via heterogeneous oxidation into sulfate on the surface of hydroxylated manganese dioxide (MnO2). Lab-scale activity tests in a fluidized bed reactor showed that the removal efficiency for a simulated flue gas containing 5000 mg·Nm(-3) SO2 could reach nearly 100% with a GHSV (gas hourly space velocity) of 10000 h(-1). The mechanism was investigated using a combination of experimental characterizations and theoretical calculations. It was found that formation of surface bound sulfate proceeds via association of SO2 with terminal hydroxyls. Both H2O and O2 are essential for the generation of reactive terminal hydroxyls, and the indirect role of O2 in heterogeneous SO2 oxidation at low temperature was also revealed. We propose that the high reactivity of terminal hydroxyls is attributed to the proper surface configuration of MnO2 to adsorb water with degenerate energies for associative and dissociative states, and maintain rapid proton dynamics. Viability analyses suggest that the desulfurization method that is based on such a direct oxidation reaction at the gas/solid interface represents a promising approach for SO2 capture. PMID:27123922

  8. Controlling dissociation by trapping trajectories in highly energetic states

    Science.gov (United States)

    de Almeida, A. K., Jr.; Egydio de Carvalho, R.; de Lima, E. F.

    2016-05-01

    We consider the non-linear dynamics of a polar diatomic molecule under the action of laser-field interactions and in the presence of a dissipation mechanism, described by the classical damped and driven one-dimensional Morse oscillator. In the absence of laser fields and dissipation, the phase space consists of a negative-energy bound region and a positive-energy dissociative region. Laser-molecule interaction changes the phase space allowing transitions from the bound to the dissociative region through chaotic routes. We show that for a spatially dependent dipole force, resonances with positive energies allow the trapping of trajectories in pseudo-bound states. We also show that, upon the introduction of dissipation, there exist non-trivial point attractors as well as chaotic attractors, which capture the trajectories in pseudo-bound states. Consequently, in addition to the parameters associated with the laser-molecule interaction, the amplitude of the dissipation acts as a control parameter of the photo-dissociation dynamics.

  9. Characteristics of covert and overt visual orienting: Evidence from attentional and oculomotor capture

    Science.gov (United States)

    Wu, Shu-Chieh; Remington, Roger W.

    2003-01-01

    Five visual search experiments found oculomotor and attentional capture consistent with predictions of contingent orienting, contrary to claims that oculomotor capture is purely stimulus driven. Separate saccade and attend-only conditions contained a color target appearing either singly, with an onset or color distractor, or both. In singleton mode, onsets produced oculomotor and attentional capture. In feature mode, capture was absent or greatly reduced, providing evidence for top-down modulation of both types of capture. Although attentional capture by color abstractors was present throughout, oculomotor capture by color occurred only when accompanied by transient change, providing evidence for a dissociation between oculomotor and attentional capture. Oculomotor and attentional capture appear to be mediated by top-down attentional control settings, but transient change may be necessary for oculomotor capture. ((c) 2003 APA, all rights reserved).

  10. Fabrication of titanate nanotubes/iron oxide magnetic composite for the high efficient capture of radionuclides: a case investigation of 109Cd(II)

    International Nuclear Information System (INIS)

    In this paper, the capture of radiocadmium (Cd(II)) by adsorption onto the titanate nanotube/iron oxide (TNT/IOM) magnetic composite as a function of contact time, pH, ionic strength, foreign cation and anion ions, humic acid (HA) and fulvic acid (FA) was studied using batch technique. The results indicated that the adsorption of Cd(II) onto the TNT/IOM magnetic composite was dependent on ionic strength at pH 9.0. Outer-sphere surface complexation were the main mechanism of Cd(II) adsorption onto the TNT/IOM magnetic composite at low pH values, whereas the adsorption was mainly dominated via inner-sphere surface complexation at high pH values. The adsorption of Cd(II) onto the TNT/IOM magnetic composite was dependent on foreign cation and anion ions at low pH values, but was independent of foreign cation and anion ions at high pH values. A positive effect of HA/FA on Cd(II) adsorption onto the TNT/IOM magnetic composite was found at low pH values, while a negative effect was observed at high pH values. From the results of Cd(II) removal by the TNT/IOM magnetic composite, the optimum reaction conditions can be obtained for the maximum removal of Cd(II) from water. It is clear that the best pH values of the system to remove Cd(II) from solution by using the TNT/IOM magnetic composite are 7.0-8.0. Considering the low cost and effective disposal of Cd(II)-contaminated wastewaters, the best condition for Cd(II) capture by the TNT/IOM magnetic composite is at room temperature and solid content of 0.5 g L-1. These results are quite important for estimating and optimizing the removal of Cd(II) and related metal ions by the TNT-based magnetic composite. (author)

  11. Diffractive dissociation and new quarks

    International Nuclear Information System (INIS)

    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

  12. Multiphoton ionization/dissociation of osmium tetroxide

    International Nuclear Information System (INIS)

    The mechanisms leading to laser multiphoton ionization and dissociation (MPI/MPD) of osmium tetroxide (OsO4) have been investigated from measurements of the kinetic energies of product ions (Os+, Os2+, OsO+, O2+, O+) and photoelectrons as a function of the laser wavelength. Neutral channels, intermediate to the dominant Os+ ionization channel, such as OsO4→OsO4-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+

  13. Mirror Writing and a Dissociative Identity Disorder

    OpenAIRE

    Catherine Le; Joyce Smith; Lewis Cohen

    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...

  14. Radiolytic dissociative gas power conversion cycles

    International Nuclear Information System (INIS)

    A gas or combined gas/steampower cycle is described. A portion of the working fluid is dissociated by radiolysis at a temperature below the thermal equilibrium temperature of the dissociated working fluid, such that the fluid is at macroscopic thermal non-equilibrium. The dissociated fluid components are then recombined to heat the working fluid. Recombination may be carried out while expanding the fluid components so as to maintain a constant temperature in a rotatory fluid engine

  15. Characterizing changes in the rate of protein-protein dissociation upon interface mutation using hotspot energy and organization.

    Directory of Open Access Journals (Sweden)

    Rudi Agius

    Full Text Available Predicting the effects of mutations on the kinetic rate constants of protein-protein interactions is central to both the modeling of complex diseases and the design of effective peptide drug inhibitors. However, while most studies have concentrated on the determination of association rate constants, dissociation rates have received less attention. In this work we take a novel approach by relating the changes in dissociation rates upon mutation to the energetics and architecture of hotspots and hotregions, by performing alanine scans pre- and post-mutation. From these scans, we design a set of descriptors that capture the change in hotspot energy and distribution. The method is benchmarked on 713 kinetically characterized mutations from the SKEMPI database. Our investigations show that, with the use of hotspot descriptors, energies from single-point alanine mutations may be used for the estimation of off-rate mutations to any residue type and also multi-point mutations. A number of machine learning models are built from a combination of molecular and hotspot descriptors, with the best models achieving a Pearson's Correlation Coefficient of 0.79 with experimental off-rates and a Matthew's Correlation Coefficient of 0.6 in the detection of rare stabilizing mutations. Using specialized feature selection models we identify descriptors that are highly specific and, conversely, broadly important to predicting the effects of different classes of mutations, interface regions and complexes. Our results also indicate that the distribution of the critical stability regions across protein-protein interfaces is a function of complex size more strongly than interface area. In addition, mutations at the rim are critical for the stability of small complexes, but consistently harder to characterize. The relationship between hotregion size and the dissociation rate is also investigated and, using hotspot descriptors which model cooperative effects within

  16. Investigation of the neutral loss of a full amino acid mass during collision-induced dissociation of the b(3)+ ion derived from a model peptide containing a 4-aminobutyric acid residue.

    Science.gov (United States)

    Talaty, Erach R; Chueachavalit, Chawalee; Osburn, Sandra; Van Stipdonk, Michael J

    2007-01-01

    In a previous study we found that a dominant fragmentation pathway observed for collision-induced dissociation (CID) of b(3)+ derived from peptides with sequence AXAG, where X is gamma-aminobutyric acid (gammaAbu) or epsilon-aminocaproic acid (Cap), involved the loss of 89 mass units (u). A neutral loss of 89 u corresponded to the free acid mass of an alanine (A) residue. This specific pathway was studied in greater detail here using a series of A(gammaAbu)AG peptides with strategic positioning of (15)N, (13)C and (2)H isotope labels. Based on the extensive labeling, several possible routes to the net elimination of 89 u are proposed. One is based on initial elimination of either aziridinone or imine and CO, followed by opening of an oxazolinone, tautomerization and elimination of H2O. Another involves formation of an aziridinone by cleavage of the N-terminal amide bond, and transfer of O and H atoms to this fragment via an H-bonded ion-molecule complex to complete the loss of 89 u. Both types of pathway include the transfer/migration of H atoms from the alpha-carbon position of gammaAbu or A residues. PMID:17610213

  17. Charmonium dissociation cross sections and charmonium dissociation rates in hadronic matter

    CERN Document Server

    Liu, Feng-Rong; Xu, Xiao-Ming

    2016-01-01

    K*-charmonium dissociation reactions in hadronic matter are studied in the Born approximation, in the quark-interchange mechanism, and with a temperature-dependent quark potential. We obtain the temperature dependence of unpolarized cross sections for K*-charmonium dissociation reactions which produce charmed mesons and charmed strange mesons. We use the cross sections for charmonium dissociation in collisions with pion, rho meson, kaon, vector kaon, and eta meson to calculate dissociation rates of charmonium with the five types of mesons. Because of the temperature dependence of the meson masses, dissociation cross sections, and meson distribution functions, the charmonium dissociation rates generally increase with the increase of temperature and decrease with the increase of charmonium momentum from 2.2 GeV/c. We find that the first derivative of the dissociation rate with respect to the charmonium momentum is zero when the charmonium is at rest. While the eta + psi' and eta + chi_c dissociation reactions c...

  18. Video Screen Capture Basics

    Science.gov (United States)

    Dunbar, Laura

    2014-01-01

    This article is an introduction to video screen capture. Basic information of two software programs, QuickTime for Mac and BlueBerry Flashback Express for PC, are also discussed. Practical applications for video screen capture are given.

  19. Dissociative recombination of organic molecular ions of relevance for interstellar clouds and Titan's upper atmosphere

    OpenAIRE

    Vigren, Erik

    2010-01-01

    This thesis presents experimental studies on the dissociative recombination (DR) of the organic molecular ions CD3CND+, CH2CHCNH+, CH3CH2CNH+, CD3CDO+, CH3CHO+ and DCOOD2+. The experiments were all performed at the heavy ion storage ring CRYRING at the Manne Siegbahn Laboratory in Stockholm, Sweden. DR is the process in which a singly charged molecular cation captures a free electron, forming a highly excited intermediate molecule which then dissociates into exclusively neutral fragments. The...

  20. Radiative electron capture

    International Nuclear Information System (INIS)

    Some data are presented for radiative electron capture by fast moving ions. The radiative electron capture spectrum is shown for O8+ in Ag, along with the energy dependence of the capture cross-section. A discrepancy between earlier data, theoretical prediction, and the present data is pointed out. (3 figs) (U.S.)

  1. Comparative study between hadron and heavy ion dissociation at high energies

    International Nuclear Information System (INIS)

    The present work deals with the dissociation of hadrons and heavy ions at high energies. In investigating hadron nucleus and nucleus-nucleus collisions, it is important to classify the experimental data, into two main classes; the coherent. and incoherent reactions. The coherent production is the main of our study. This process called electromagnetic dissociation (ED) and can be differentiate into coulomb dissociation (CD) and diffraction dissociation (DD). This work explains the experimental data of collisions of hadrons K± (70 GeV/c) and π(340 Gc V/c) and heavy ions 6Li, 7Li, 12C and16O at Dubna energies (3-4.5 A GeV/c)with emulsion target, in the frame of some models and theories which describe the mechanism of ED dissociation

  2. First-principles study of molecular NO dissociation on Ir(100) surface

    Science.gov (United States)

    Erikat, I. A.; Hamad, B. A.; Khalifeh, J. M.

    2014-02-01

    The dissociation of NO on Ir(100) surface is investigated using density functional theory (DFT). The pathway and transition state (TS) of the dissociation of NO molecule are determined using climbing image nudge elastic band (CI-NEB). The prerequisite state of NO dissociation is determining the most stable sites of the reactant and products. We found that the most energetically stable sites are the hollow for N atom and the bridge for NO molecule as well as O atom. We found that the bending of NO is the first step of the dissociation reaction due to the increase of the back-donation from the d-band of Ir to 2 π ∗ orbital of NO, which causes the weakening of NO bond. The dissociation energy barrier of NO molecule on Ir(100) surface is 0.49 eV.

  3. a Measurement of the Homogeneous Rate of Thermal Dissociation of Uranium Hexafluoride by Shock Tube Densitometry

    Science.gov (United States)

    Scoles, Stephen Wesley

    1990-01-01

    A determination of the rate of homogeneous thermal dissociation of UF_6 is reported. The high temperature region of a shock tube generated flow was used to dissociate UF_6. Laser -schlieren diagnostic techniques were used to measure post -shock density gradient and shock wave velocity, from which the dissociation rate constant and post-shock conditions were determined. The unimolecular dissociation theory of Rice, Ramsparger, and Kassel was used to model the temperature - and density-dependent rate constants. When extrapolated to the high density limit the dissociation rate constant obtained is:rm k_infty = 3.51times 10^{13}{bf e}^{{-64.6+/-6.3 {kcal over mole}over R_{U}T }}{1over sec}.This result agrees with a reliable theoretical calculation by another investigator, but differs by two orders of magnitude from the only other experimental measurements in the open literature.

  4. The influence of family environment on dissociation in pediatric injury patients.

    Science.gov (United States)

    Nugent, Nicole R; Sledjeski, Eve M; Christopher, Norman C; Delahanty, Douglas L

    2011-10-01

    Emerging support for the roles of both early trauma and family environment in the development of dissociative symptomatology is complicated by the frequent co-occurrence of dysfunctional family environments and childhood maltreatment. The present investigation prospectively examined the influence of family environment on dissociative symptom course in 82 youths (8-18 years) who experienced accidental injury. The primary caretaker reported on six-week family environment (including family cohesion and adaptability) and on youth symptoms of dissociation prior to injury at six weeks and at six months; dissociation prior to injury was assessed via retrospective parent account at the six-week timepoint. Adolescents (aged 11-18) also reported on their own dissociative symptoms at six weeks. Latent growth modeling indicated that youth in more cohesive family environments evidenced decreased symptoms of dissociation at the six-week intercept (z = -2.80). Furthermore, parent income was negatively related to symptoms of dissociation at intercept (z = -1.96) and parent education was associated with a decrease in youth dissociation symptoms over time (z = -2.57). The present findings provide support for the importance of acute family environment in pediatric post-injury adjustment and further highlight the importance of parent resources, including income and education, in post-injury adjustment. PMID:21757482

  5. Molecular dissociation in dilute gas

    International Nuclear Information System (INIS)

    The charge state distributions (CSD) produced during molecular dissociation are important to both Trace Element Accelerator Mass Spectrometry (TEAMS) and the ion implantation industry. The CSD of 1.3 - 1.7 MeV SiN+, SiMg+, SiMn+, and SiZn+ molecules have been measured for elements that do not form atomic negative ions (N, Mg, Mn, and Zn) using a NEC Tandem Pelletron accelerator. The molecules were produced in a Cs sputter negative ion source, accelerated, magnetically analyzed, and then passed through an N2 gas cell. The neutral and charged breakups where analyzed using an electrostatic deflector and measured with particle detectors. Equilibrium CSD were determined and comparisons made between molecular and atomic ion data. copyright 1999 American Institute of Physics

  6. Theory of dissociative tunneling ionization

    CERN Document Server

    Svensmark, Jens; Madsen, Lars Bojer

    2016-01-01

    We present a theoretical study of the dissociative tunneling ionization process. Analytic expressions for the nuclear kinetic energy distribution of the ionization rates are derived. A particularly simple expression for the spectrum is found by using the Born-Oppenheimer (BO) approximation in conjunction with the reflection principle. These spectra are compared to exact non-BO ab initio spectra obtained through model calculations with a quantum mechanical treatment of both the electronic and nuclear degrees freedom. In the regime where the BO approximation is applicable imaging of the BO nuclear wave function is demonstrated to be possible through reverse use of the reflection principle, when accounting appropriately for the electronic ionization rate. A qualitative difference between the exact and BO wave functions in the asymptotic region of large electronic distances is shown. Additionally the behavior of the wave function across the turning line is seen to be reminiscent of light refraction. For weak fiel...

  7. One- and two-phonon capture processes in quantum dots

    DEFF Research Database (Denmark)

    Magnúsdóttir, Ingibjörg; Uskov, Alexander; Bischoff, Svend;

    2002-01-01

    Multiphonon capture processes are investigated theoretically and found to contribute efficiently to the carrier injection into quantum dots. It is shown that two-phonon capture contributes where single-phonon capture is energetically inhibited and can lead to electron capture times of a few...

  8. Capture Their Attention: Capturing Lessons Using Screen Capture Software

    Science.gov (United States)

    Drumheller, Kristina; Lawler, Gregg

    2011-01-01

    When students miss classes for university activities such as athletic and academic events, they inevitably miss important class material. Students can get notes from their peers or visit professors to find out what they missed, but when students miss new and challenging material these steps are sometimes not enough. Screen capture and recording…

  9. An Investigation into the Effects of Mn Promotion on the Activity and Selectivity of Co/SiO2 for Fischer - Tropsch Synthesis: Evidence for Enhanced CO Adsorption and Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Gregory R.; Werner, Sebastian; Bell, Alexis T. (LBNL); (UCB)

    2016-03-04

    Mn is an effective promoter for improving the activity and selectivity of Co-based Fischer-Tropsch synthesis (FTS) catalysts, but the mechanism by which this promoter functions is poorly understood. The work reported here was aimed at defining the manner in which Mn interacts with Co and determining how these interactions affect the activity and selectivity of Co. Detailed measurements are reported for the kinetics of FTS as a function of Mn/Co ratio, temperature, and reactant partial pressure. These data are described by a single, two-parameter rate expression. Mn promotion was found to increase both the apparent rate constant for CO consumption and the CO adsorption constant. Further evidence for enhanced CO adsorption and dissociation was obtained from measurements of temperature-programmed desorption of CO and CO disproportionation rates, respectively. Our quantitative analysis of elemental maps obtained by STEM-EDS revealed that the promoter accumulates preferentially on the surface of Co nanoparticles at low Mn loadings, resulting in a rapid onset of improvements in the product selectivity as the Mn loading increases. For catalysts prepared with loadings higher than Mn/Co = 0.1, the additional Mn accumulates in the form of nanometer-scale particles of MnO on the support. In situ IR spectra of adsorbed CO show that Mn promotion increases the abundance of adsorbed CO with weakened C-O bonds. Furthermore, it is proposed that the cleavage of the C-O bond is promoted through Lewis acid-base interactions between the Mn2+ cations located at the edges of MnO islands covering the Co nanoparticles and the O atom of CO adsorbates adjacent to the MnO islands. The observed decrease in selectivity to CH4 and the increased selectivity to C5+ products with increasing Mn/Co ratio are attributed to a decrease in the ratio of adsorbed H to CO on the surface of the supported Co nanoparticles.

  10. A three-dimensional study on the formation and dissociation of methane hydrate in porous sediment by depressurization

    International Nuclear Information System (INIS)

    Highlights: ► A method to synthesize typical hydrate-bearing samples is proposed. ► Hydrate dissociation in three-dimensional cell occurs throughout the hydrate zone. ► The sharp interface is hardly found during hydrate depressurization dissociation. ► Hydrate dissociation rates at different locations are not uniform. ► Thermal buffering and heat transfer influence on gas production rate of hydrate. - Abstract: A middle-scale reactor equipped with 16 thermocouples was used to investigate the formation and dissociation of methane hydrate in sediment in three dimensions. A method was proposed to form hydrate homogeneously distributed in sediment, i.e., using frozen sand instead of wet sand with pore water. With the formed hydrate sample, hydrate dissociation experiment by depressurization was carried out at a constant pressure of 1.0 MPa. It was found that gas hydrate dissociation occurs throughout the hydrate zone, which controlled by both mass transfer and heat transfer throughout the stages. The sharp-interface is hardly found during the hydrate dissociation. The thermal buffering was observed at the temperature of (271.5–272.2) K during the hydrate dissociation process. The ice arisen from hydrate dissociation slows the hydrate dissociation rate below the ice point, which will affect gas production rate. It may be more reasonable that the depressurization method is used in the initial stage and the thermal stimulation method is used in the later stage in the process of gas recovery from hydrate reservoir.

  11. Experimental measurements and thermodynamic modeling of refrigerant hydrates dissociation conditions

    International Nuclear Information System (INIS)

    Highlights: • Dissociation conditions of refrigerant hydrates are studied experimentally and theoretically. • Refrigerants R23, R134a, R125a, R22, R410A, R407C and R507C are studied experimentally. • A thermodynamic model able to predict refrigerant hydrates dissociation conditions is proposed. • The results show good agreement between the experimental and predicted values. - Abstract: This study aims to investigate dissociation conditions of refrigerant hydrates both experimentally and theoretically. For this purpose, dissociation conditions of refrigerants R23, R134a, R125a, R22, R410A, R407C and R507C have been measured experimentally. A thermodynamic model that is able to predict refrigerant hydrates dissociation conditions in the various phase equilibrium regions has been proposed as well. Refrigerants modeled in this study include pure refrigerants: R11, R12, R13, R22, R23, R32, R134a, R141b, R143a, R125a, R152a, and mixed refrigerants: R11 + R12, R11 + R114, R12 + R114, R32 + R125a + R134a (R407C), R32 + R125a (R410A). For the modeling of the fluid and hydrate phases, the Peng-Robinson equation of state modified by Stryjek and Vera and the MHV2 GE-EoS mixing rule along with the UNIFAC (original) activity coefficient and van der Waals–Platteeuw (vdW–P) models were employed. The results show good agreement between the experimental and predicted values

  12. Overriding auditory attentional capture.

    Science.gov (United States)

    Dalton, Polly; Lavie, Nilli

    2007-02-01

    Attentional capture by color singletons during shape search can be eliminated when the target is not a feature singleton (Bacon & Egeth, 1994). This suggests that a "singleton detection" search strategy must be adopted for attentional capture to occur. Here we find similar effects on auditory attentional capture. Irrelevant high-intensity singletons interfered with an auditory search task when the target itself was also a feature singleton. However, singleton interference was eliminated when the target was not a singleton (i.e., when nontargets were made heterogeneous, or when more than one target sound was presented). These results suggest that auditory attentional capture depends on the observer's attentional set, as does visual attentional capture. The suggestion that hearing might act as an early warning system that would always be tuned to unexpected unique stimuli must therefore be modified to accommodate these strategy-dependent capture effects. PMID:17557587

  13. Overriding auditory attentional capture

    OpenAIRE

    Dalton, Polly; Lavie, Nilli

    2007-01-01

    Attentional capture by color singletons during shape search can be eliminated when the target is not a feature singleton (Bacon & Egeth, 1994). This suggests that a "singleton detection" search strategy must be adopted for attentional capture to occur. Here we find similar effects on auditory attentional capture. Irrelevant high-intensity singletons interfered with an auditory search task when the target itself was also a feature singleton. However, singleton interference was eliminated when ...

  14. Dissociating the decision making functions of older adults

    OpenAIRE

    Griffin, Charlie

    2009-01-01

    The aim of this study was to use two variants of the Iowa gambling test, which have been shown to dissociate between patients with dorsolateral and orbitofrontal cortex lesions, to investigate whether decision making deficits found in normal older adults are similar to patterns associated with patients with lesions to the dorsolateral or obritofrontal cortex. This study was designed to advance previous findings that subsets of older adults are impaired on the Iowa Gambling task by determin...

  15. 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. PMID:26431902

  16. DTA and TGA study of MeSo4 (Me = Fe, Co, Ni dissociation in the presence of coke

    Directory of Open Access Journals (Sweden)

    Boyanov B.S.

    2002-01-01

    Full Text Available MeSO4 (Me = Fe, Co, Ni dissociation is investigated in order to estimate the effect of temperature, time and presence of coke as reducer on the degree and mechanism of dissociation. It is proved that the presence of coke decreases the dissociation temperature considerably and increases the degree of MeSO4 dissociation. Based on the obtained experimental data, a mechanism of the processes is proposed. The obtained results can be used in the industrial production of non-ferrous metals for explaining the processes that take place in the reduction of zinc and lead cakes in order to achieve favorable environmental, technical and economic results.

  17. Effect of components nature of mixed nonaqueous solvents on electrolytic dissociation of some electrolytes

    International Nuclear Information System (INIS)

    On the basis of a conductimetric investigation of the dissociation of NaI and Bu4NI in binary isodielectric mixed non-aqueous solvents it is shown that the dissociation of these electrolytes depends on the nature and the quantitative content in the mixture of the polar component and that this is bound up with the selective solvation of ions by the polar molecules of the mixed solvent. The dissociation of NaI is greater than that of Bu4NI owing to greater solvation of the cation Na+ compared with the cation Bu4N+. (author)

  18. Dissociation in schizophrenia and borderline personality disorder

    Directory of Open Access Journals (Sweden)

    Pec O

    2014-03-01

    Full Text Available Ondrej Pec,1,2 Petr Bob,1,3 Jiri Raboch1 1Center for Neuropsychiatric Research of Traumatic Stress, Department of Psychiatry, First Faculty of Medicine, Charles University, Prague, 2Psychotherapeutic and Psychosomatic Clinic ESET, Prague, 3Central European Institute of Technology, Faculty of Medicine, Masaryk University, Brno, Czech Republic Background: Dissociation likely plays a key role in schizophrenia and borderline personality disorder (BPD, although empirical studies that compare specific manifestations of these symptoms in schizophrenia and BPD are rare. In this context, the purpose of this study was to compare the occurrence of dissociative and other psychopathological symptoms in these disorders, and to assess the possible influence of antipsychotic medication on the dissociative symptoms. Methods: We assessed 31 patients with schizophrenia and 36 patients with BPD. Dissociative symptoms were measured by the Dissociative Experiences Scale (DES, symptoms related to stress and traumatic experiences were assessed using the Trauma Symptom Checklist-40 (TSC-40, and other psychopathological symptoms were measured with the Health of the Nation Outcome Scales (HoNOS. We also assessed actual daily doses of antipsychotic medication in chlorpromazine equivalents in all participants. Results: The results show that symptoms of traumatic stress measured by the TSC-40 had significantly higher scores in the BPD group. The data also show that dissociative symptoms (DES were significantly correlated with symptoms of traumatic stress (TSC-40 and with symptoms assessed by the HoNOS. Remarkably significant correlations were found between levels of antipsychotic medication and the DES and between antipsychotic medication and the depersonalization/derealization component of the DES in BPD patients. Conclusion: The results support an important role of dissociative processes in schizophrenia and BPD and suggest a significant relationship between manifestations

  19. Theory of dissociative tunneling ionization

    Science.gov (United States)

    Svensmark, Jens; Tolstikhin, Oleg I.; Madsen, Lars Bojer

    2016-05-01

    We present a theoretical study of the dissociative tunneling ionization process. Analytic expressions for the nuclear kinetic energy distribution of the ionization rates are derived. A particularly simple expression for the spectrum is found by using the Born-Oppenheimer (BO) approximation in conjunction with the reflection principle. These spectra are compared to exact non-BO ab initio spectra obtained through model calculations with a quantum mechanical treatment of both the electronic and nuclear degrees of freedom. In the regime where the BO approximation is applicable, imaging of the BO nuclear wave function is demonstrated to be possible through reverse use of the reflection principle, when accounting appropriately for the electronic ionization rate. A qualitative difference between the exact and BO wave functions in the asymptotic region of large electronic distances is shown. Additionally, the behavior of the wave function across the turning line is seen to be reminiscent of light refraction. For weak fields, where the BO approximation does not apply, the weak-field asymptotic theory describes the spectrum accurately.

  20. Atom capture and loss in ion molecule collisions

    International Nuclear Information System (INIS)

    Progress is reported in measuring the energy and angular distribution of protons emerging with velocity close to the beam velocity from the target region when Ar+ beams collide with a CH4 target and ArH+ beams collide with a He target at asymptotically high speeds. The protons result from the transfer of a target constituent to the projectile (atom capture) or from the dissociation of the projectile molecule in the collision (atom loss). For atom capture processes the Thomas peak is clearly observed. 10 refs., 3 figs

  1. Peptide and protein sequence analysis by electron transfer dissociation mass spectrometry

    OpenAIRE

    Syka, John E. P.; Coon, Joshua J.; Schroeder, Melanie J.; Shabanowitz, Jeffrey; Hunt, Donald F.

    2004-01-01

    Peptide sequence analysis using a combination of gas-phase ion/ion chemistry and tandem mass spectrometry (MS/MS) is demonstrated. Singly charged anthracene anions transfer an electron to multiply protonated peptides in a radio frequency quadrupole linear ion trap (QLT) and induce fragmentation of the peptide backbone along pathways that are analogous to those observed in electron capture dissociation. Modifications to the QLT that enable this ion/ion chemistry are presented, and automated ac...

  2. Carbon Capture and Storage

    NARCIS (Netherlands)

    Benson, S.M.; Bennaceur, K.; Cook, P.; Davison, J.; Coninck, H. de; Farhat, K.; Ramirez, C.A.; Simbeck, D.; Surles, T.; Verma, P.; Wright, I.

    2012-01-01

    Emissions of carbon dioxide, the most important long-lived anthropogenic greenhouse gas, can be reduced by Carbon Capture and Storage (CCS). CCS involves the integration of four elements: CO 2 capture, compression of the CO2 from a gas to a liquid or a denser gas, transportation of pressurized CO 2

  3. CAPTURED India Country Evaluation

    NARCIS (Netherlands)

    O'Donoghue, R.; Brouwers, J.H.A.M.

    2012-01-01

    This report provides the findings of the India Country Evaluation and is produced as part of the overall CAPTURED End Evaluation. After five years of support by the CAPTURED project the End Evaluation has assessed that results are commendable. I-AIM was able to design an approach in which health fol

  4. Precursor anion states in dissociative electron attachment to chlorophenol isomers

    Science.gov (United States)

    Kossoski, F.; Varella, M. T. do N.

    2016-07-01

    We report a theoretical study on low-energy (chlorophenol isomers, namely, para-chlorophenol (pCP), meta-chlorophenol (mCP), and ortho-chlorophenol (oCP). The calculations were performed with the Schwinger multichannel method with pseudopotentials, and analysis of the computed integral cross sections and virtual orbitals revealed one σCCl ∗ , one σOH ∗ , and three π∗ shape resonances. We show that electron capture into the two lower lying π∗ orbitals initiates dissociative processes that lead to the elimination of the chloride ion, accounting for the two overlapping peaks where this fragment was observed. Despite the relatively small differences on the energetics of the π∗ resonances, a major isomeric effect was found on their corresponding autodetachment lifetimes, which accounts for the observed increasing cross sections in the progression pCP chlorophenols and phenol actually takes place by a mechanism in which the incoming electron is directly attached to the dissociative σOH ∗ orbital.

  5. CO2 dissociation in vortex-stabilised microwave plasmas

    Science.gov (United States)

    Welzel, S.; Bongers, W. A.; Graswinckel, M. F.; van de Sanden, M. C. M.

    2014-10-01

    Plasma-assisted gas conversion techniques are widely considered as efficient building blocks in a future energy infrastructure which will be based on intermittent, renewable electricity sources. CO2 dissociation in high-frequency plasmas is of particular interest in carbon capture and utilisation process chains for the production of CO2-neutral fuels. In order to achieve efficient plasma processes of high throughput specifically designed gas flow and power injection regimes are required. In this contribution vortex-stabilised microwave plasmas in undiluted CO2 were studied in a pressure range from 170 to 1000 mbar at up to 1 kW (forward) injected power, respectively. The CO2 depletion was measured downstream, e.g. by means of mass spectrometry. Although the system configuration was entirely not optimised, energy efficiencies of nearly 40%, i.e. close to the thermal dissociation limit, and conversion efficiencies of up to 23% were achieved. Additionally, spatially-resolved emission spectroscopy was applied to map the axial and radial distribution of excited atomic (C, O) and molecular (CO, C2) species along with their rotational temperatures. Eindhoven University of Technology, Postbox 513, 5600 MB Eindhoven.

  6. Numerical simulation of the electrodeionization (EDI) process accounting for water dissociation

    International Nuclear Information System (INIS)

    The electrodeionization process (EDI) is usually operated at overlimiting current density, and is thus characterized by water dissociation and concentration polarization. We attempt to study the useful and harmful effects of water dissociation on the EDI process. A numerical steady state model was established to simulate the process of EDI, accounting for the effects of water dissociation. The differences in concentration polarization of membranes were investigated to study the effects of water dissociation on cation and anion membranes. Protons produced by water dissociation caused the resin to transform into the H-form. The H-form resin, which has high conductivity and high transport number, depletes protons in the interstitial solution. This explains the experimentally detected phenomenon that at high current densities, the pH value of the effluency of the dilute compartment (DC) stops decreasing when current increases. We suggest that the useful role of water dissociation in EDI is due to the H-form resin bringing more salt cations of the interstitial solution into the resin phase, thus producing a high conductivity channel for the electro-migration of the salt cations. This mechanism avoids the decrease in salt ion conductivity brought about by concentration polarization. The disadvantageous effect of concentration polarization on the transportation of salt ions in interstitial solution is thus lessened. An intermediate point between the useful and harmful effects of water dissociation was determined by the dependence of current efficiency and removal rate for both cations and anions as a function of current density.

  7. Hydrogen loss in aminobutanoic acid isomers by the σ* resonance formed in electron capture

    International Nuclear Information System (INIS)

    The mechanism of a hydrogen loss reaction upon dissociative electron attachment to organic acids and amino acids has been a matter of controversy. In this study, we investigate this process for three isomers of aminobutanoic acid and the deuterated analogue of the α isomer (αAD) in the electron energy range 0-2.5 eV. We implement the resonant R-matrix theory, applying a one-dimensional model involving electron capture into the σ*(OH) orbital which reproduces convincingly the conspicuous features of the experimental cross sections, i.e. the pronounced cusps at the vibrational excitation threshold, the substantially different shapes of the three constitutional isomers and the characteristic differences between αA and its isotopologue αAD. (paper)

  8. Research Reports: Hallucinogens and Dissociative Drugs

    Science.gov (United States)

    ... dangerous behavior. Hallucinogens such as LSD, psilocybin, peyote, DMT, and ayahuasca cause emotions to swing wildly and ... Dissociative Drugs? How Do Hallucinogens (LSD, Psilocybin, Peyote, DMT, and Ayahuasca) Affect the Brain and Body? What ...

  9. Coulomb dissociation at nonrelativistic and relativistic energies

    International Nuclear Information System (INIS)

    The author studies the breakup of deuterons on nuclei in the framework of DWBA theories which are based on the spectator model. The discrepancies for heavy targets are explained by the mechanism of the Coulomb dissociation. (HSI)

  10. Direct thermal neutron capture

    International Nuclear Information System (INIS)

    We discuss the direct-capture theory pertaining to primary electric dipole (E1) transitions following slow-neutron capture. For light nuclides that we have studied (including 9Be, 12C, 13C, 24Mg, 25Mg, 26Mg, 32S, 33S, 34S, 40Ca, and 44Ca), estimates of direct-capture cross sections using optical-model potentials with physically realistic parameters, are in reasonable agreement with the data. Minor disagreements that exist are consistent with extrapolations to light nuclides of generally accepted formulations of compound-nucleus capture. We also discuss the channel-capture approximation which is, in general, a good representation of these cross sections in heavier nuclei particularly if the scattering lengths are not different from the corresponding potential radii. We also draw attention to cases where the use of this formula leads to inaccurate predictions. 9 refs., 1 fig., 2 tab

  11. Muon capture in hydrogen

    International Nuclear Information System (INIS)

    In this lecture I will mainly speak about the recent results obtained by the Saclay-CERN-Bologna (SCB) collaboration on the muon capture rate at rest in liquid hydrogen.In the first talk I shall first briefly remind the theoretical description of the capture process, then describe the experimental difficulties and procedures and finally present the results obtained. In the second talk I shall compare them to other capture experiments on the proton and present the informations that are provided by muon capture in hydrogen, especially for the PCAC hypothesis, the second class currents and the μ-e universality. Finally I shall present the possible muon capture experiments on the proton that could still be undertaken in order to improve our present knowledge of the subject

  12. Combining gas phase electron capture and IRMPD action spectroscopy to probe the electronic structure of a metastable reduced organometallic complex containing a non-innocent ligand.

    Science.gov (United States)

    Katari, Madanakrishna; Payen de la Garanderie, Eleonore; Nicol, Edith; Steinmetz, Vincent; van der Rest, Guillaume; Carmichael, Duncan; Frison, Gilles

    2015-10-21

    Combining electron capture dissociation mass spectrometry and infrared multiple photon dissociation action spectroscopy allows the formation, selection and characterisation of reduced metal complexes containing non-innocent ligands. Zinc complexes containing diazafluorenone ligands have been studied and the localisation of the single electron on the metal atom in the mono-ligated complex has been demonstrated. PMID:26051020

  13. ELECTRON DETACHMENT DISSOCIATION OF DERMATAN SULFATE OLIGOSACCHARIDES

    OpenAIRE

    Wolff, Jeremy J.; Laremore, Tatiana N.; BUSCH, ALEXANDER M.; Linhardt, Robert J.; Amster, I. Jonathan

    2007-01-01

    The structural characterization of glycosaminoglycans (GAG) oligosaccharides has been a longstanding challenge in the field of mass spectrometry. In this work, we present the application of electron detachment dissociation (EDD) Fourier transform mass spectrometry to the analysis of dermatan sulfate (DS) oligosaccharides up to 10 residues in length. The EDD mass spectra of DS oligosaccharides were compared to their infrared multiphoton dissociation (IRMPD) mass spectra. EDD produces more abun...

  14. Dissociation of ultracold molecules with Feshbach resonances

    OpenAIRE

    Dürr, Stephan; Volz, Thomas; Rempe, Gerhard

    2004-01-01

    Ultracold molecules are associated from an atomic Bose-Einstein condensate by ramping a magnetic field across a Feshbach resonance. The reverse ramp dissociates the molecules. The kinetic energy released in the dissociation process is used to measure the widths of 4 Feshbach resonances in 87Rb. This method to determine the width works remarkably well for narrow resonances even in the presence of significant magnetic-field noise. In addition, a quasi-mono-energetic atomic wave is created by ju...

  15. Compulsive symptoms in dissociative (conversion) disorder

    OpenAIRE

    Agarwal, Arun Lata

    2006-01-01

    According to Mayer-Gross, Slater and Roth's classical textbook Clinical psychiatry, obsessive-compulsive symptoms are rarely seen in hysteria. The release of obsessive-compulsive symptoms is said to occur only in those who are constitutionally predisposed. In this context, the case of a young woman with dissociative (conversion) disorder, who presented with compulsive symptoms, is reported. In her case, the dissociative phenomena manifested as compulsive symptoms without concomitant predispos...

  16. Spontaneous exciton dissociation in carbon nanotubes

    OpenAIRE

    Kumamoto, Y.; Yoshida, M.; Ishii, A; Yokoyama, A.; Shimada, T; Kato, Y. K.

    2013-01-01

    Simultaneous photoluminescence and photocurrent measurements on individual single-walled carbon nanotubes reveal spontaneous dissociation of excitons into free electron-hole pairs. Correlation of luminescence intensity and photocurrent shows that a significant fraction of excitons are dissociating during their relaxation into the lowest exciton state. Furthermore, the combination of optical and electrical signals also allows for extraction of the absorption cross section and the oscillator st...

  17. Dissociation of gaseous zwitterion glycine-betaine by slow electrons.

    Science.gov (United States)

    Kopyra, J; Abdoul-Carime, H

    2010-05-28

    In this work, we investigate dissociation processes induced by low-energy electrons to gas phase N,N,N-trimethylglycine [glycine-betaine, (CH(3))(3)N(+)CH(2)COO(-)] molecules. Glycine-betaine represents a model system for zwitterions. All negative fragments are observed to be produced only at subelectronic excitation energies (<4 eV). With the exception of the loss of a neutral H atom that could arise from any C[Single Bond]H bond breaking, we tentatively suggest that the zwitterion dissociates exclusively from the fragmentation of the cation site of the molecule, subsequent to the attachment of the excess electron. Within the context of radiation induced damage to biological systems, the present findings contribute to a more complete description of the fragmentation mechanism occurring to amino acids, peptides, and proteins since they adopt usually a zwitterion structure. PMID:20515090

  18. Who Done It, Actually? Dissociative Identity Disorder for the Criminologist

    Directory of Open Access Journals (Sweden)

    Adah Sachs

    2015-07-01

    Full Text Available Dissociative Identity Disorder (DID (American Psychiatric Association 2013 is examined in this paper from the perspective of its relevance to the criminologist. As this psychiatric condition is linked to severe and prolonged childhood abuse, accounts of DID patients inevitably involve reports of serious crimes, in which the person was the victim, perpetrator or witness. These reports can thus contain crucial information for criminal investigations by the police or for court proceedings. However, due to the person’s dissociation, such reports are often very confusing, hard to follow, hard to believe and difficult to obtain. They also frequently state that the person had ‘no choice’, a thorny notion for the criminologist (as well as for the clinician. Through the analysis of clinical examples, the paper explores how decisions are made by a person with DID, the notions of choice and ‘competent reasoning’, and the practical and ethical ways for interviewing a person with DID.

  19. Stability Analysis of Methane Hydrate-Bearing Soils Considering Dissociation

    Directory of Open Access Journals (Sweden)

    Hiromasa Iwai

    2015-06-01

    Full Text Available It is well known that the methane hydrate dissociation process may lead to unstable behavior such as large ground deformations, uncontrollable gas production, etc. A linear instability analysis was performed in order to investigate which variables have a significant effect on the onset of the instability behavior of methane hydrate-bearing soils subjected to dissociation. In the analysis a simplified viscoplastic constitutive equation is used for the soil sediment. The stability analysis shows that the onset of instability of the material system mainly depends on the strain hardening-softening parameter, the degree of strain, and the permeability for water and gas. Then, we conducted a numerical analysis of gas hydrate-bearing soil considering hydrate dissociation in order to investigate the effect of the parameters on the system. The simulation method used in the present study can describe the chemo-thermo-mechanically coupled behaviors such as phase changes from hydrates to water and gas, temperature changes and ground deformation. From the numerical results, we found that basically the larger the permeability for water and gas is, the more stable the simulation results are. These results are consistent with those obtained from the linear stability analysis.

  20. Hydrate-based technology for CO2 capture from fossil fuel power plants

    International Nuclear Information System (INIS)

    Graphical abstract: Application of hydrate based technology on carbon dioxide capture and storage (CCS). - Highlights: • Hydrate-based CO2–N2 separation data was obtained for flow in porous media. • Tetrahydrofuran and sodium dodecyl sulphate are used as additives simultaneously. • Solution movement rarely occurs when residual solution saturations are low. • Bothe of pressure and temperature have remarkable impacts on gas compositions. • A suitable operation parameter choice is proposed for hydrate-based CO2 capture. - Abstract: Hydrate-based CO2 capture is a promising technology. To obtain fundamental data for a flowing system, we measured the distribution of pore solution to analyse hydrate formation/dissociation and gas separation properties. An orthogonal experiment was carried out to investigate the effects of glass beads, flow rates, pressures and temperatures on it. Magnetic resonance imaging (MRI) images were obtained using a spin echo multi-slice pulse sequence. Hydrate saturations were calculated quantitatively using an MRI mean intensity. The results show that hydrate blockages were frequently present. During the hydrate formation and dissociation process, the movement of the solution occurred in cycles. However, the solution movement rarely occurred for residual solution saturations obtained with a high backpressure. The solution concentrate phenomenon occurred mostly in BZ-04. The highest hydrate saturation was 30.2%, and the lowest was 0.70%. Unlike that in BZ-01, there was no stability present in BZ-02 and BZ-04. The different CO2 concentrations for the three processes of each cycle verified hydrate formation during the gas flow process. The highest CO2 concentration was 38.8%, and the lowest one was 11.4%. To obtain high hydrate saturation and good separation effects, the values of 5.00 MPa, 1.0 ml min−1 and 280.00 K were chosen. For the gas flow process, only the pressure had a significant impact on gas composition, and all the

  1. Dissociable brain biomarkers of fluid intelligence.

    Science.gov (United States)

    Paul, Erick J; Larsen, Ryan J; Nikolaidis, Aki; Ward, Nathan; Hillman, Charles H; Cohen, Neal J; Kramer, Arthur F; Barbey, Aron K

    2016-08-15

    Cognitive neuroscience has long sought to understand the biological foundations of human intelligence. Decades of research have revealed that general intelligence is correlated with two brain-based biomarkers: the concentration of the brain biochemical N-acetyl aspartate (NAA) measured by proton magnetic resonance spectroscopy (MRS) and total brain volume measured using structural MR imaging (MRI). However, the relative contribution of these biomarkers in predicting performance on core facets of human intelligence remains to be well characterized. In the present study, we sought to elucidate the role of NAA and brain volume in predicting fluid intelligence (Gf). Three canonical tests of Gf (BOMAT, Number Series, and Letter Sets) and three working memory tasks (Reading, Rotation, and Symmetry span tasks) were administered to a large sample of healthy adults (n=211). We conducted exploratory factor analysis to investigate the factor structure underlying Gf independent from working memory and observed two Gf components (verbal/spatial and quantitative reasoning) and one working memory component. Our findings revealed a dissociation between two brain biomarkers of Gf (controlling for age and sex): NAA concentration correlated with verbal/spatial reasoning, whereas brain volume correlated with quantitative reasoning and working memory. A follow-up analysis revealed that this pattern of findings is observed for males and females when analyzed separately. Our results provide novel evidence that distinct brain biomarkers are associated with specific facets of human intelligence, demonstrating that NAA and brain volume are independent predictors of verbal/spatial and quantitative facets of Gf. PMID:27184204

  2. Excited State Formation in Electron Capture by Slow Multiply Charged Ions

    International Nuclear Information System (INIS)

    Translational energy spectroscopy (TES) has been used to study one-electron capture by H and He-like ions of C, N and O in both H and H2 at energies below 1 keV amu-1. Similar measurements have been carried out for He2+ ions in the hydrocarbons CH4, C2H4, C2H6 and H2O at energies within the range 250-2000 eV amu-1. One-electron capture by O6+ ions in H2O, CO2 and CH4 and by C4+ ions in CH4 have also been studied in the range 200-1500 eV amu-1. The main excited product states have been identified, their relative importance assessed and, in some cases, cross-sections determined. In the molecular targets, contributions to one-electron capture from non-dissociative and dissociative mechanisms as well as from two-electron capture into autoionizing states has also been determined. In all cases, the highly selective nature of the electron capture process is confirmed even in the case of molecules with many possible fragmentation channels involving a wide range of energy defects. In the case of H, the main product channels are well predicted by reaction windows calculated using a Landau-Zener approach. However, the same approach applied to molecules, where both non-dissociative and dissociative mechanisms are significant, is found to be of limited use. (author)

  3. A digital image capture method: legal and criminalistic aspects

    OpenAIRE

    Šiurna, Žilvinas

    2007-01-01

    The graduating paper focuses on the digital image capture method in criminalistic and also on its legal regulation and practical resort in the law enforcement institutions‘ investigations of criminal acts. The digital image capture is one of the methods of digital image capture in criminalistic. Its structure contains digital photography and digital video recording. The digital photography is used for strategical and investigative photography. The usage of the digital image capture method inv...

  4. 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...

  5. Exciton dissociation at organic small molecule donor-acceptor interfaces (Presentation Recording)

    Science.gov (United States)

    Robey, Steven W.

    2015-08-01

    Exciton dissociation at organic semiconductor donor-acceptor (D-A) heterojunctions is critical for the performance of organic photovoltaic (OPV) structures. Interfacial charge separation and recombination processes control device efficiency. We have investigated these fundamental interfacial issues using time-resolved two-photon photoemission (TR-2PPE), coupled with the formation of well-controlled D-A structures by organic molecular beam epitaxy. The interfacial electronic and molecular structure of these model interfaces was well-characterized using scanning tunneling microscopy and ultraviolet photoemission. Exciton dissociation dynamics were investigated by using a sub-picosecond pump pulse to create Pc π-->π* transitions, producing a population of singlet (S1) Pc excitons. The subsequent decay dynamics of this population was monitored via photoemission with a time-delayed UV pulse. For CuPcC60 interfaces, S1 exciton population decay in the interfacial CuPc layer was much faster than decay in the bulk due to interfacial charge separation. The rate constant for exciton dissociation was found to be ≍ 7 x 10 12 sec-1 (≍ 140 fs). Excitons that lose energy via intersystem crossing (ISC) to triplet levels dissociate approximately 500 to 1000 times slower. The dependence of exciton dissociation on separation was also studied. Exciton dissociation falls of rapidly with distance from the interface. Dissociation from the 2nd, and subsequent, layers of H2Pc is reduced by at least a factor of 10 from that in the interfacial layer. Finally, investigations of the relative efficiency for interfacial exciton dissociation by alternative acceptors based on perylene cores, (perylene tetracarboxylic dianhydride, or PTCDA) compared to fullerene-based acceptors such as C60 will also be discussed.

  6. Environment assisted electron capture

    International Nuclear Information System (INIS)

    Electrons scattering off isolated atoms or positive atomic ions may be captured in the non-resonant photorecombination or resonant dielectronic recombination processes with the excess energy carried off by a photon. We demonstrate that in a medium a new interatomic process becomes important, where in the electron capture by an atom or atomic ion the energy is transferred to a neigbouring species ionising it. We discuss different manifestations of this interatomic Coulombic electron capture and estimate its efficiency for a number of realistic systems.

  7. Thermal dissociation behavior and dissociation enthalpies of methane-carbon dioxide mixed hydrates.

    Science.gov (United States)

    Kwon, Tae-Hyuk; Kneafsey, Timothy J; Rees, Emily V L

    2011-06-30

    Replacement of methane with carbon dioxide in hydrate has been proposed as a strategy for geologic sequestration of carbon dioxide (CO(2)) and/or production of methane (CH(4)) from natural hydrate deposits. This replacement strategy requires a better understanding of the thermodynamic characteristics of binary mixtures of CH(4) and CO(2) hydrate (CH(4)-CO(2) mixed hydrates), as well as thermophysical property changes during gas exchange. This study explores the thermal dissociation behavior and dissociation enthalpies of CH(4)-CO(2) mixed hydrates. We prepared CH(4)-CO(2) mixed hydrate samples from two different, well-defined gas mixtures. During thermal dissociation of a CH(4)-CO(2) mixed hydrate sample, gas samples from the head space were periodically collected and analyzed using gas chromatography. The changes in CH(4)-CO(2) compositions in both the vapor phase and hydrate phase during dissociation were estimated based on the gas chromatography measurements. It was found that the CO(2) concentration in the vapor phase became richer during dissociation because the initial hydrate composition contained relatively more CO(2) than the vapor phase. The composition change in the vapor phase during hydrate dissociation affected the dissociation pressure and temperature; the richer CO(2) in the vapor phase led to a lower dissociation pressure. Furthermore, the increase in CO(2) concentration in the vapor phase enriched the hydrate in CO(2). The dissociation enthalpy of the CH(4)-CO(2) mixed hydrate was computed by fitting the Clausius-Clapeyron equation to the pressure-temperature (PT) trace of a dissociation test. It was observed that the dissociation enthalpy of the CH(4)-CO(2) mixed hydrate lays between the limiting values of pure CH(4) hydrate and CO(2) hydrate, increasing with the CO(2) fraction in the hydrate phase. PMID:21604671

  8. Picosecond dissociation of amyloid fibrils with infrared laser: A nonequilibrium simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Hoang Viet, Man; Roland, Christopher, E-mail: cmroland@ncsu.edu; Sagui, Celeste, E-mail: sagui@ncsu.edu [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202 (United States); Derreumaux, Philippe; Nguyen, Phuong H., E-mail: phuong.nguyen@ibpc.fr [Laboratoire de Biochimie Théorique, UPR 9080, CNRS Université Denis Diderot, Sorbonne Paris Cité IBPC, 13 rue Pierre et Marie Curie, 75005 Paris (France); Li, Mai Suan [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Institute for Computational Science and Technology, SBI Building, Quang Trung Software City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City (Viet Nam)

    2015-10-21

    Recently, mid-infrared free-electron laser technology has been developed to dissociate amyloid fibrils. Here, we present a theoretical framework for this type of experiment based on laser-induced nonequilibrium all-atom molecular dynamics simulations. We show that the fibril is destroyed due to the strong resonance between its amide I vibrational modes and the laser field. The effects of laser irradiation are determined by a balance between fibril formation and dissociation. While the overall rearrangements of the fibril finish over short time scales, the interaction between the peptides and the solvent continues over much longer times indicating that the waters play an important role in the dissociation process. Our results thus provide new insights into amyloid fibril dissociation by laser techniques and open up new venues to investigate the complex phenomena associated with amyloidogenesis.

  9. Quantum–classical correspondence and the role of the dipole function in molecular dissociation

    International Nuclear Information System (INIS)

    We consider the quantum and classical dissociation dynamics of heteronuclear diatomic molecules induced by infrared laser pulses. The field–molecule interaction is given by the product of the time-dependent electric field and the molecule permanent dipole. We investigate the influence of the dipole function in molecular dissociation. We show that the dissociation can be suppressed at certain external field frequencies for a nonlinear and finite-range dipole function. The correspondence between quantum and classical results is established by relating classical Fourier amplitudes to discrete–continuum quantum matrix elements. - Highlights: • A finite-range dipole can prevent laser-induced dissociation for particular external frequencies. • Quantum and classical calculations show good agreement when the system is initially in excited levels. • An approximation of discrete–continuum matrix elements by Fourier components is obtained

  10. Picosecond dissociation of amyloid fibrils with infrared laser: A nonequilibrium simulation study

    International Nuclear Information System (INIS)

    Recently, mid-infrared free-electron laser technology has been developed to dissociate amyloid fibrils. Here, we present a theoretical framework for this type of experiment based on laser-induced nonequilibrium all-atom molecular dynamics simulations. We show that the fibril is destroyed due to the strong resonance between its amide I vibrational modes and the laser field. The effects of laser irradiation are determined by a balance between fibril formation and dissociation. While the overall rearrangements of the fibril finish over short time scales, the interaction between the peptides and the solvent continues over much longer times indicating that the waters play an important role in the dissociation process. Our results thus provide new insights into amyloid fibril dissociation by laser techniques and open up new venues to investigate the complex phenomena associated with amyloidogenesis

  11. Studies on plasma dissociation of zircon

    International Nuclear Information System (INIS)

    Zircon (zirconium silicate) is a major source of zirconium metal. Extraction of zirconium involves chlorination step to convert zirconium silicate to ZrCl4 and SiCl4. SiCl4 is separated and zirconium tetrachloride is reduced with magnesium to yield zirconium metal. Instead of this direct chlorination of zircon, it can be converted to zirconia by thermal plasma dissociation followed by alkali leaching process to separate silica. The resulting zirconium oxide can be used for zirconium extraction. This would result in considerable savings of chlorine consumption and also would eliminate the SiCl4 separation step. The Laser and Plasma Technology Division has developed a 20 kW laboratory 1 scale plasma reactor, which consists of a DC plasma torch mounted on a water cooled reaction chamber, DC power source, water cooling and gas feed system and a powder feeder. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation studies were carried out over 5-16 kW power range. The plasma processed product was characterized by x-ray diffraction technique, which showed that it consisted of zirconium dioxide and silica. The extent of dissociation was estimated by gravimetric method involving alkali leaching of silica. Results of the study indicate that the extent of dissociation strongly depends on input power and other parameters such as plasma gas flow rate. Complete dissociation could be achieved at an input power of 12 kW. The average temperature at the nozzle exit of the plasma torch has been calculated for various input power levels. Calculations on heat transfer to the particles and residence time required to effect dissociation of zircon particles injected in the plasma jet have been carried out for various input power levels and particle sizes ranging from 20-150 microns. Details of the experiments and results will be discussed in the paper. (author)

  12. Neutrinoless double electron capture

    CERN Document Server

    Kotila, J; Iachello, F

    2015-01-01

    Direct determination of the neutrino mass is at the present time one of the most important aims of experimental and theoretical research in nuclear and particle physics. A possible way of detection is through neutrinoless double electron capture, $0\

  13. Electron capture by fluorinated fullerene anions in collisions with Xe atoms

    DEFF Research Database (Denmark)

    Boltalina, OV; Hvelplund, P; Jørgensen, Thomas J. D.;

    2000-01-01

    Electron capture by 50-keV fluorinated fullerene anions (C60Fn- 18dissociative electron capture was found to depend strongly on the ion pro...... production method and on the number of attached F atoms. The absolute size of the cross section similar to 10(-16) cm(2) has been modeled within the over-the-barrier model......Electron capture by 50-keV fluorinated fullerene anions (C60Fn- 18dissociative electron capture was found to depend strongly on the ion...

  14. Dynamical Process of Dissociation of Excitons in Polymer Chains with Impurities

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong-Xia; ZHAO Hui; CHEN Yu-Guang

    2011-01-01

    @@ Within an extended Su-Schrieffer-Heeger model including impurity interactions,the dynamical process of exciton dissociation in the presence of an external electric field is investigated by using a non-adiabatic evolution method Under the action of impurities,the stability as well as the effective mass of the exciton is reduced.Our results show that the field required to dissociate the excitons depends sensitively on the strength of the impurity potential.As the impurity potential strength increases,the dissociation field decreases effectively.The theoretical results are expected to provide useful predictions concerning which polymers with properly impurity-assisted interactions are likely to be more suitable for use in organic solar cells.%Within an extended Su-Schrieffer-Heeger model including impurity interactions, the dynamical process ofexciton dissociation in the presence of an external electric field is investigated by using a non-adiabatic evolution method. Under the action of impurities, the stability as well as the effective mass of the exciton is reduced. Our results show that the field required to dissociate the excitons depends sensitively on the strength of the impurity potential. As the impurity potential strength increases, the dissociation field decreases effectively. The theoretical results are expected to provide useful predictions concerning which polymers with properly impurity-assisted interactions are likely to be more suitable for use in organic solar cells.

  15. Activists versus Captured Regulators

    OpenAIRE

    Daubanes, Julien; Rochet, Jean-Charles

    2013-01-01

    We analyze the consequences of activism in a regulated industry where the regulator has been captured by the industry. Unlike ordinary economic agents, activists are insensitive to monetary incentives. Moreover, they are less well informed than regulators and their actions generate dead-weight costs. Yet we find that activism may increase social welfare because it disciplines captured regulators and reduces the social cost of imperfect regulatory systems.

  16. Muon capture by tritium

    International Nuclear Information System (INIS)

    The muon capture rate is computed with realistic wave function for the initial tritium nuclei (Faddeev equations on configuration space with realistic potentials), and plane wave approximation for the final three neutrons, with the effective Hamiltonian of Fujii and Primakoff for muon capture and via a non energy weighted sum rule. Such a forbidden transition is hoped to be a probe for exchange current contributions

  17. Quantum entanglement and the dissociation process of diatomic molecules

    International Nuclear Information System (INIS)

    In this work, we investigate quantum entanglement-related aspects of the dissociation process of some selected, representative homo- and heteronuclear diatomic molecules. This study is based upon high-quality ab initio calculations of the (correlated) molecular wavefunctions involved in the dissociation processes. The values of the electronic entanglement characterizing the system in the limit cases corresponding to (i) the united-atom representation and (ii) the asymptotic region when atoms dissociate are discussed in detail. It is also shown that the behaviour of the electronic entanglement as a function of the reaction coordinate R exhibits remarkable correspondences with the phenomenological description of the physically meaningful regimes comprising the processes under study. In particular, the extrema of the total energies and the electronic entanglement are shown to be associated with the main physical changes experienced by the molecular spatial electronic density, such as charge depletion and accumulation or bond cleavage regions. These structural changes are characterized by several selected descriptors of the density, such as the Laplacian of the electronic molecular distributions (LAP), the molecular electrostatic potential (MEP) and the atomic electric potentials fitted to the MEP.

  18. Quantum entanglement and the dissociation process of diatomic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, Rodolfo O; Molina-Espiritu, Moyocoyani [Departamento de Quimica, Universidad Autonoma Metropolitana, 09340-Mexico DF (Mexico); Flores-Gallegos, Nelson [Unidad Profesional Interdisciplinaria de IngenierIa, Campus Guanajuato del Instituto Politecnico Nacional, 36275-Guanajuato (Mexico); Plastino, A R; Angulo, Juan Carlos; Dehesa, Jesus S [Instituto Carlos I de Fisica Teorica y Computacional, and Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, 18071-Granada (Spain); Antolin, Juan, E-mail: esquivel@xanum.uam.mx, E-mail: arplastino@ugr.es [Departamento de Fisica Aplicada, EUITIZ, Universidad de Zaragoza, 50018-Zaragoza (Spain)

    2011-09-14

    In this work, we investigate quantum entanglement-related aspects of the dissociation process of some selected, representative homo- and heteronuclear diatomic molecules. This study is based upon high-quality ab initio calculations of the (correlated) molecular wavefunctions involved in the dissociation processes. The values of the electronic entanglement characterizing the system in the limit cases corresponding to (i) the united-atom representation and (ii) the asymptotic region when atoms dissociate are discussed in detail. It is also shown that the behaviour of the electronic entanglement as a function of the reaction coordinate R exhibits remarkable correspondences with the phenomenological description of the physically meaningful regimes comprising the processes under study. In particular, the extrema of the total energies and the electronic entanglement are shown to be associated with the main physical changes experienced by the molecular spatial electronic density, such as charge depletion and accumulation or bond cleavage regions. These structural changes are characterized by several selected descriptors of the density, such as the Laplacian of the electronic molecular distributions (LAP), the molecular electrostatic potential (MEP) and the atomic electric potentials fitted to the MEP.

  19. Dissociative attachment reactions of electrons with strong acid molecules

    International Nuclear Information System (INIS)

    Using the flowing afterglow/Langmuir probe (FALP) technique, we have determined (at variously 300 and 570 K) the dissociative attachment coefficients β for the reactions of electrons with the common acids HNO3 (producing NO-2) and H2SO4 (HSO-4), the superacids FSO3H (FSO-3), CF3SO3H (CF3SO-3), ClSO3H (ClSO-3,Cl-), the acid anhydride (CF3SO2)2O (CF3SO-3), and the halogen halides HBr (Br-) and HI (I-). The anions formed in the reactions are those given in the parentheses. The reactions with HF and HCl were investigated, but did not occur at a measurable rate since they are very endothermic. Dissociative attachment is rapid for the common acids, the superacids, and the anhydride, the measured β being appreciable fractions of the theoretical maximum β for such reactions, β/sub max/. The HI reaction is very fast ( βapprox.β/sub max/) but the HBr reaction occurs much more slowly because it is significantly endothermic. The data indicate that the extreme acidity of the (Bronsted-type) superacids has its equivalence in the very efficient gas-phase dissociative attachment which these species undergo when reacting with free electrons. The anions of the superacids generated in these reactions, notably FSO-3 and CF3SO-3, are very stable (unreactive) implying exceptionally large electron affinities for the FSO3 and CF3SO3 radicals

  20. Dissociation of CH4 on Ni(111) and Ru(0001)

    DEFF Research Database (Denmark)

    Egeberg, Rasmus; Ullmann, S.; Alstrup, I.;

    2002-01-01

    Recently steps and surface imperfections were proven by Dahl et al. [Phys. Rev. Lett. 83 (1999) 1814] to have an all-dominating effect on the N, dissociation on Ru(0 0 0 1). In this paper the dissociative sticking of CH4 on the closepacked surfaces of Ni and Ru has been investigated in order to...... clarify to what extent a similar effect is present in these systems. The apparent activation energies found were 74 +/- 10 and 51 +/- 6 kJ/mol on Ni(1 1 1) and Ru(0 0 0 1) respectively. On neither Ru(0 0 0 1) nor Ni(1 1 1) did we observe a significant decrease of the overall sticking coefficient when the...... impinging CH4 molecules. We conclude that in these types of experiments steps play a minor role for CH4 dissociation on Ru(0 0 0 1) and Ni(l 1 1). In a temperature programmed oxidation reaction we observe that carbon from the steps of Ru(0 0 0 1) leaves the surface at lower temperatures than carbon from the...

  1. [Dissociating between Enhancing and Impairing Effects of Emotion on Cognition].

    Science.gov (United States)

    Dolcos, Florin; Denkova, Ekaterina

    2016-01-01

    Objectives Emerging evidence suggests that emotion can have both enhancing and impairing effects on various cognitive processes. These opposing effects can be identified at different levels, both within the same cognitive process and across different processes, as well as at more general levels, such as in the case of the response to stress. The aim of the present review is to discuss recent advances in the mechanisms underlying the enhancing and impairing effects of emotion on different aspects within the same process (e.g., episodic memory) and across specific cognitive processes (perception vs. episodic memory, working memory vs. episodic memory), as well as in the context of the response to stress.Emerging Evidence The available evidence points to a number of aspects that dissociate the opposing effects of emotion on cognition. (i) Opposing effects within episodic memory can be attributed to different accounts, involving dissociation at different levels: central vs. peripheral trade-off, high vs. low prioritization of information processing, and items encoding vs. the formation of complex associations. (ii) The opposing effects across cognitive processes, such as perception and episodic memory, can be linked to dissociation between immediate/impairing vs. long-term/enhancing effects, which are mediated by common and dissociable neural mechanisms, involving bottom-up and top-down processes. (iii) Finally, in the larger context of the response to stress, emotional stress can lead to opposing effects depending on the degree, context, and controllability of the stressors.Conclusions Overall, the present review highlights the need to consider the various factors that can influence enhancing or impairing effects of emotion on cognition, in studies investigating emotion-cognition interactions. These issues are important for understanding mechanisms of emotion-cognition interactions not only in healthy functioning but also in emotional disturbances, where these

  2. Muon capture on 3H

    CERN Document Server

    Golak, J; Witala, H; Topolnicki, K; Kamada, H; Nogga, A; Marcucci, L E

    2016-01-01

    The muon capture on 3H leading to muonic neutrino and three neutrons in the final state is studied under full inclusion of final state interactions. Predictions for the three-body break-up of 3H are calculated with the AV18 potential, augmented by the Urbana IX three-nucleon force. Our results are based on the single nucleon weak current operator comprising the dominant relativistic corrections. This work is a natural extension of our investigations of the muon capture on 3He leading to 3H or n+d or n+n+p and muonic neutrino in the final state, presented in Phys. Rev. C90, 024001 (2014).

  3. Isotherm-Based Thermodynamic Models for Solute Activities of Organic Acids with Consideration of Partial Dissociation.

    Science.gov (United States)

    Nandy, Lucy; Ohm, Peter B; Dutcher, Cari S

    2016-06-23

    Organic acids make up a significant fraction of the organic mass in atmospheric aerosol particles. The calculation of gas-liquid-solid equilibrium partitioning of the organic acid is therefore critical for accurate determination of atmospheric aerosol physicochemical properties and processes such as new particle formation and activation to cloud condensation nuclei. Previously, an adsorption isotherm-based statistical thermodynamic model was developed for capturing solute concentration-activity relationships for multicomponent aqueous solutions over the entire concentration range (Dutcher et al. J. Phys. Chem. C/A 2011, 2012, 2013), with model parameters for energies of adsorption successfully related to dipole-dipole electrostatic forces in solute-solvent and solvent-solvent interactions for both electrolytes and organics (Ohm et al. J. Phys. Chem. A 2015). However, careful attention is needed for weakly dissociating semivolatile organic acids. Dicarboxylic acids, such as malonic acid and glutaric acid are treated here as a mixture of nondissociated organic solute (HA) and dissociated solute (H(+) + A(-)). It was found that the apparent dissociation was greater than that predicted by known dissociation constants alone, emphasizing the effect of dissociation on osmotic and activity coefficient predictions. To avoid additional parametrization from the mixture approach, an expression was used to relate the Debye-Hückel hard-core collision diameter to the adjustable solute-solvent intermolecular distance. An improved reference state treatment for electrolyte-organic aqueous mixtures, such as that observed here with partial dissociation, has also been proposed. This work results in predictive correlations for estimation of organic acid and water activities for which there is little or no activity data. PMID:27222917

  4. Quarkonium suppression: Gluonic dissociation vs. colour screening

    Indian Academy of Sciences (India)

    Binoy Krishna Patra; Dinesh Kumar Srivastava

    2003-05-01

    We evaluate the suppression of / production in an equilibrating quark gluon plasma for two competing mechanisms: Debye screening of colour interaction and dissociation due to energetic gluons. Results are obtained for S + S and Au + Au collisions at RHIC and LHC energies. At RHIC energies the gluonic dissociation of the charmonium is found to be equally important for both the systems while the screening of the interaction plays a significant role only for the larger systems. At LHC energies the Debye mechanism is found to dominate both the systems. While considering the suppression of directly produced $\\Upsilon$ at LHC energies, we find that only the gluonic dissociation mechanism comes into play for the initial conditions taken from the self screened parton cascade model in these studies.

  5. Muon capture at PSI

    CERN Document Server

    Winter, Peter

    2010-01-01

    Measuring the rate of muon capture in hydrogen provides one of the most direct ways to study the axial current of the nucleon. The MuCap experiment uses a negative muon beam stopped in a time projection chamber operated with ultra-pure hydrogen gas. Surrounded by a decay electron detector, the lifetime of muons in hydrogen can be measured to determine the singlet capture rate Lambda_s to a final precision of 1%. The capture rate determines the nucleon's pseudoscalar form factor g_p. A first result, g_p = 7.3 +- 1.1, has been published and the final analysis of the full statistics will reduce the error by a factor of up to 3. Muon capture on the deuteron probes the weak axial current in the two-nucleon system. Within the framework of effective field theories the calculation of such two-nucleon processes involving the axial current requires the knowledge of one additional low energy constant which can be extracted from the doublet capture rate Lambda_d. The same constant then allows to model-independently calcu...

  6. Dissociative Recombination of Molecular Ions for Astrochemistry

    Science.gov (United States)

    Novotny, Oldrich; Becker, A.; Buhr, H.; Fleischmann, Andreas; Gamer, Lisa; Geppert, W.; Krantz, C.; Kreckel, H.; Schwalm, D.; Spruck, K.; Wolf, A.; Savin, Daniel Wolf

    2014-06-01

    Dissociative recombination (DR) of molecular ions is a key chemical process in the cold interstellar medium (ISM). DR affects the composition, charge state, and energy balance of such environments. Astrochemical models of the ISM require reliable total DR cross sections as well as knowledge of the chemical composition of the neutral DR products. We have systematically measured DR for many astrophysically relevant molecular ions utilizing the TSR storage ring at the Max-Planck-Institute for Nuclear Physics (MPIK) in Heidelberg, Germany. We used the merged ion-electron beam technique combined with an energy- and position-sensitive imaging detector and are able to study DR down to plasma temperatures as low as 10 K. The DR count rate is used to obtain an absolute merged beams DR rate coefficient from which we can derive a thermal rate coefficient needed for plasma models. Additionally we determine the masses of the DR products by measuring their kinetic energy in the laboratory reference frame. This allows us to assign particular DR fragmentation channels and to obtain their branching ratios. All this information is particularly important for understanding DR of heteronuclear polyatomic ions. We will present DR results for several ions recently investigated at TSR. A new Cryogenic Storage Ring (CSR) is currently being commissioned at MPIK. With the chamber cooled down to ~10 K and a base pressure better than 10-13 mbar, this setup will allow internal cooling of the stored ions down to their rotational ground states, thus opening a new era in DR experiments. New technological challenges arise due to the ultracold, ultra-high vacuum environment of the CSR and thus the detection techniques used at TSR cannot be easily transferred to CSR. We will present new approaches for DR fragment detection in cryogenic environment. This work is supported in part by NASA and the NSF.

  7. Extreme UV induced dissociation of amorphous solid water and crystalline water bilayers on Ru(0001)

    Science.gov (United States)

    Liu, Feng; Sturm, J. M.; Lee, Chris J.; Bijkerk, Fred

    2016-04-01

    The extreme ultraviolet (EUV, λ = 13.5 nm) induced dissociation of water layers on Ru(0001) was investigated. We irradiated amorphous and crystalline water layers on a Ru crystal with EUV light, and measured the surface coverage of remaining water and oxygen as a function of radiation dose by temperature programmed desorption (TPD). The main reaction products are OH and H with a fraction of oxygen from fully dissociated water. TPD spectra from a series of exposures reveal that EUV promotes formation of the partially dissociated water overlayer on Ru. Furthermore, loss of water due to desorption and dissociation is also observed. The water loss cross sections for amorphous and crystalline water are measured at 9 ± 2 × 10- 19 cm2 and 5 ± 1 × 10- 19 cm2, respectively. Comparison between the two cross sections suggests that crystalline water is more stable against EUV induced desorption/dissociation. The dissociation products can oxidize the Ru surface. For this early stage of oxidation, we measured a smaller (compared to water loss) cross section at 2 × 10- 20 cm2, which is 2 orders of magnitude smaller than the photon absorption cross section (at 92 eV) of gas phase water. The secondary electron (SE) contributions to the cross sections are also estimated. From our estimation, SE only forms a small part (20-25%) of the observed photon cross section.

  8. Experimental Study on Mechanism of Depressurizing Dissociation of Methane Hydrate under Saturated Pore Fluid

    Institute of Scientific and Technical Information of China (English)

    Sun Youhong; Su Kai; Guo Wei; Li Bing; Jia Rui

    2016-01-01

    Sediment-hosted hydrate reservoir often contains saturated pore lfuid, which changes the heat transfer and mass transfer characteristics of the hydrate reservoir. The exploitation of hydrate under saturated pore lfuid using depressurization is simulated experimentally to investigate the inlfuence of particle size of porous media, dissociation temperature, pressure drop and injected lfuid type on gas production behavior. Homogeneous methane hydrate was ifrstly formed in frozen quartz sand. With the formed hydrate sample, hydrate dissociation experiments by depressurization were conducted. The test results showed that the gas production rate of hydrate under saturated pore lfuid was substantially inlfuenced by the particle size, the pressure drop and the injected lfuid type, while it was inlfuenced little by the dissociation temperature. The hydrate dissociates faster under larger pressure drop and in the presence of smaller porous media within the experimental region. The dissociation rate increases with an increasing lfuid salinity in the initial stage, while it decreases in the later stage. The increase of gas diffusion resistance resulted from ionic hydration atmosphere in saturated chloride solution impeded the dissociation of hydrate. It can be solved by increasing the pressure drop and decreasing the lfuid salinity in the process of gas recovery from hydrate reservoir.

  9. Redox control of fast ligand dissociation from Escherichia coli cytochrome bd

    International Nuclear Information System (INIS)

    Bacterial bd-type quinol oxidases, such as cytochrome bd from Escherichia coli, contain three hemes, but no copper. In contrast to heme-copper oxidases and similarly to globins, single electron-reduced cytochrome bd forms stable complexes with O2, NO and CO at ferrous heme d. Kinetics of ligand dissociation from heme d 2+ in the single electron- and fully-reduced cytochrome bd from E. coli has been investigated by rapid mixing spectrophotometry at 20 oC. Data show that (i) O2 dissociates at 78 s-1 (ii) NO and CO dissociation is fast as compared to heme-copper oxidases and (iii) dissociation in the single electron-reduced state is hindered as compared to the fully-reduced enzyme. Presumably, rapid ligand dissociation requires reduced heme b 595. As NO, an inhibitor of respiratory oxidases, is involved in the immune response against microbial infection, the rapid dissociation of NO from cytochrome bd may have important bearings on the patho-physiology of enterobacteria

  10. PKCδ regulates force signaling during VEGF/CXCL4 induced dissociation of endothelial tubes.

    Directory of Open Access Journals (Sweden)

    Joshua Jamison

    Full Text Available Wound healing requires the vasculature to re-establish itself from the severed ends; endothelial cells within capillaries must detach from neighboring cells before they can migrate into the nascent wound bed to initiate angiogenesis. The dissociation of these endothelial capillaries is driven partially by platelets' release of growth factors and cytokines, particularly the chemokine CXCL4/platelet factor-4 (PF4 that increases cell-cell de-adherence. As this retraction is partly mediated by increased transcellular contractility, the protein kinase c-δ/myosin light chain-2 (PKCδ/MLC-2 signaling axis becomes a candidate mechanism to drive endothelial dissociation. We hypothesize that PKCδ activation induces contractility through MLC-2 to promote dissociation of endothelial cords after exposure to platelet-released CXCL4 and VEGF. To investigate this mechanism of contractility, endothelial cells were allowed to form cords following CXCL4 addition to perpetuate cord dissociation. In this study, CXCL4-induced dissociation was reduced by a VEGFR inhibitor (sunitinib malate and/or PKCδ inhibition. During combined CXCL4+VEGF treatment, increased contractility mediated by MLC-2 that is dependent on PKCδ regulation. As cellular force is transmitted to focal adhesions, zyxin, a focal adhesion protein that is mechano-responsive, was upregulated after PKCδ inhibition. This study suggests that growth factor regulation of PKCδ may be involved in CXCL4-mediated dissociation of endothelial cords.

  11. Heat Transfer Analysis of Methane Hydrate Sediment Dissociation in a Closed Reactor by a Thermal Method

    Directory of Open Access Journals (Sweden)

    Mingjun Yang

    2012-05-01

    Full Text Available The heat transfer analysis of hydrate-bearing sediment involved phase changes is one of the key requirements of gas hydrate exploitation techniques. In this paper, experiments were conducted to examine the heat transfer performance during hydrate formation and dissociation by a thermal method using a 5L volume reactor. This study simulated porous media by using glass beads of uniform size. Sixteen platinum resistance thermometers were placed in different position in the reactor to monitor the temperature differences of the hydrate in porous media. The influence of production temperature on the production time was also investigated. Experimental results show that there is a delay when hydrate decomposed in the radial direction and there are three stages in the dissociation period which is influenced by the rate of hydrate dissociation and the heat flow of the reactor. A significant temperature difference along the radial direction of the reactor was obtained when the hydrate dissociates and this phenomenon could be enhanced by raising the production temperature. In addition, hydrate dissociates homogeneously and the temperature difference is much smaller than the other conditions when the production temperature is around the 10 °C. With the increase of the production temperature, the maximum of ΔToi grows until the temperature reaches 40 °C. The period of ΔToi have a close relation with the total time of hydrate dissociation. Especially, the period of ΔToi with production temperature of 10 °C is twice as much as that at other temperatures. Under these experimental conditions, the heat is mainly transferred by conduction from the dissociated zone to the dissociating zone and the production temperature has little effect on the convection of the water in the porous media.

  12. Suppression of X-ray-induced dissociation of H2O molecules in dense ice under pressure

    Science.gov (United States)

    Fukui, Hiroshi; Hiraoka, Nozomu; Hirao, Naohisa; Aoki, Katsutoshi; Akahama, Yuichi

    2016-05-01

    We investigated molecular dissociation induced by 10-keV X-ray irradiation in dense ice at pressures up to 40 GPa at 300 K. The dissociation yield estimated from the oxygen K-edge X-ray Raman spectra, showed that the molecular dissociation was enhanced up to 14 GPa and gradually suppressed on further compression to 40 GPa. The molecular dissociation was detected for a rather narrow pressure span of 2–40 GPa by the X-ray spectroscopy. The pressure variation of the dissociation yield was similar to that observed in the electric conductivity of ice VII and likely interpreted in terms of proton mobility.

  13. Suppression of X-ray-induced dissociation of H2O molecules in dense ice under pressure.

    Science.gov (United States)

    Fukui, Hiroshi; Hiraoka, Nozomu; Hirao, Naohisa; Aoki, Katsutoshi; Akahama, Yuichi

    2016-01-01

    We investigated molecular dissociation induced by 10-keV X-ray irradiation in dense ice at pressures up to 40 GPa at 300 K. The dissociation yield estimated from the oxygen K-edge X-ray Raman spectra, showed that the molecular dissociation was enhanced up to 14 GPa and gradually suppressed on further compression to 40 GPa. The molecular dissociation was detected for a rather narrow pressure span of 2-40 GPa by the X-ray spectroscopy. The pressure variation of the dissociation yield was similar to that observed in the electric conductivity of ice VII and likely interpreted in terms of proton mobility. PMID:27221010

  14. Muon Capture in Deuterium

    CERN Document Server

    Ricci, P; Mosconi, B; Smejkal, J

    2009-01-01

    Model dependence of the capture rates of the negative muon capture in deuterium is studied starting from potential models and the weak two-body meson exchange currents constructed in the tree approximation and also from an effective field theory. The tree one-boson exchange currents are derived from the hard pion chiral Lagrangians of the $N \\Delta \\pi \\rho \\omega a_1$ system. If constructed in conjunction with the one-boson exchange potentials, the capture rates can be calculated consistently. On the other hand, the effective field theory currents, constructed within the heavy baryon chiral perturbation theory, contain a low energy constant $\\hat d ^R$ that cannot be extracted from data at the one-particle level nor determined from the first principles. Comparative analysis of the results for the doublet transition rate allows us to extract the constant $\\hat d ^R$.

  15. The relationship between different types of dissociation and psychosis-like experiences in a non-clinical sample.

    Science.gov (United States)

    Humpston, Clara S; Walsh, Eamonn; Oakley, David A; Mehta, Mitul A; Bell, Vaughan; Deeley, Quinton

    2016-04-01

    This study investigated whether detachment-type dissociation, compartmentalisation-type dissociation or absorption was most strongly associated with psychosis-like experiences in the general population. Healthy participants (N=215) were tested with the Dissociative Experiences Scale (DES, for detachment-related dissociative experiences); the Harvard Group Scale of Hypnotic Susceptibility (HGSHS: A, for dissociative compartmentalisation); the Tellegen Absorption Scale (TAS, for non-clinical 'functional' dissociative experience); and two measures of psychotic-like experiences, the 21-item Peters et al. Delusions Inventory (PDI-21) and the Cardiff Anomalous Perceptions Scale (CAPS). In multiple regression analyses, DES and TAS but not HGSHS: A scores were found to be significantly associated with PDI-21 and CAPS overall scores. A post hoc hierarchical cluster analysis checking for cluster overlap between DES and CAPS items, and the TAS and CAPS items showed no overlap between items on the DES and CAPS and minimal overlap between TAS and CAPS items, suggesting the scales measure statistically distinct phenomena. These results show that detachment-type dissociation and absorption, but not compartmentalisation-type dissociation are significantly associated with psychosis-like experiences in a non-clinical population. PMID:26896781

  16. US Spacesuit Knowledge Capture

    Science.gov (United States)

    Chullen, Cinda; Thomas, Ken; McMann, Joe; Dolan, Kristi; Bitterly, Rose; Lewis, Cathleen

    2011-01-01

    The ability to learn from both the mistakes and successes of the past is vital to assuring success in the future. Due to the close physical interaction between spacesuit systems and human beings as users, spacesuit technology and usage lends itself rather uniquely to the benefits realized from the skillful organization of historical information; its dissemination; the collection and identification of artifacts; and the education of those in the field. The National Aeronautics and Space Administration (NASA), other organizations and individuals have been performing United States (U.S.) Spacesuit Knowledge Capture since the beginning of space exploration. Avenues used to capture the knowledge have included publication of reports; conference presentations; specialized seminars; and classes usually given by veterans in the field. More recently the effort has been more concentrated and formalized whereby a new avenue of spacesuit knowledge capture has been added to the archives in which videotaping occurs engaging both current and retired specialists in the field presenting technical scope specifically for education and preservation of knowledge. With video archiving, all these avenues of learning can now be brought to life with the real experts presenting their wealth of knowledge on screen for future learners to enjoy. Scope and topics of U.S. spacesuit knowledge capture have included lessons learned in spacesuit technology, experience from the Gemini, Apollo, Skylab and Shuttle programs, hardware certification, design, development and other program components, spacesuit evolution and experience, failure analysis and resolution, and aspects of program management. Concurrently, U.S. spacesuit knowledge capture activities have progressed to a level where NASA, the National Air and Space Museum (NASM), Hamilton Sundstrand (HS) and the spacesuit community are now working together to provide a comprehensive closed-looped spacesuit knowledge capture system which includes

  17. Capturing Polyradical Protein Cations after an Electron Capture Event: Evidence for their Stable Distonic Structures in the Gas Phase

    Science.gov (United States)

    Baba, Takashi; Campbell, J. Larry

    2015-08-01

    We report on the formation and "capture" of polyradical protein cations after an electron capture event. Performed in a unique electron-capture dissociation (ECD) instrument, these experiments can generate reduced forms of multiply protonated proteins by sequential charge reduction using electrons with ~1 eV. The true structures of these possible polyradicals is considered: Do the introduced unpaired electrons recombine quickly to form a new two-electron bond, or do these unpaired electrons exist as radical sites with appropriate chemical reactivity? Using an established chemical probe—radical quenching with molecular oxygen—we demonstrate that these charge-reduced protein cations are indeed polyradicals that form adducts with up to three molecules of oxygen (i.e., tri-radical protein cations) that are stable for at least 100 ms.

  18. Carbon monoxide dissociative attachment and resonant dissociation by electron-impact

    Science.gov (United States)

    Laporta, V.; Tennyson, J.; Celiberto, R.

    2016-02-01

    Low-energy dissociative electron attachment and resonant electron impact dissociation of CO molecule are considered. Ro-vibrationally resolved cross sections and rate coefficients for both the processes are calculated using an ab-initio model based on the low-lying \\text{X}{{}2}\\Pi resonance of CO-. Final results show that the cross sections increases very rapidly as a function of the ro-vibrational level; these cross sections should be useful for understanding kinetic dissociation of CO in strongly non-equilibrium plasmas.

  19. Dissociative electron attachment to water and heavy water

    International Nuclear Information System (INIS)

    We will present new results on the dissociative electron attachment cross sections of the production of OH-, O- and H- formed from water vapor and the corresponding deuterated species. A crossed beams experiment already described in the literature was used. Furthermore, the effect of temperature on the formation of the mentioned negative fragment ions was investigated. An upcoming review article about inelastic collisions of electrons with water has shown discrepancies in previous studies. Our results are compared to the available previous data and show good agreement concerning the relative cross sections ratios of the ions, however, differences are observed in the energy positions of the resonances. (author)

  20. Blackbody-induced radiative dissociation of cationic SF 6 clusters

    DEFF Research Database (Denmark)

    Toker, Jonathan; Rahinov, I.; Schwalm, D.;

    2012-01-01

    The stability of cationic SF5+(SF6)n−1 clusters was investigated by measuring their blackbody-induced radiative dissociation (BIRD) rates. The clusters were produced in a supersonic expansion ion source and stored in an electrostatic ion-beam trap at room temperature, where their abundances and...... lifetimes were measured. Using the “master equation” approach, relative binding energies of an SF6 unit in the clusters could be extracted from the storage-time dependence of the survival probabilities. The results allow for a deeper insight into the effect of a localized charge on the structure and...... stability of SF6-based clusters....

  1. Microstructural and analytical analysis of plasma dissociated zircon

    International Nuclear Information System (INIS)

    The investigation of the microstructure and distribution of impurities was carried out on plasma dissociated zircon (PDZ). The morphology of the PDZ and crystalline nature of the zirconia was determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) while energy dispersive X-ray spectrometry (EDS) provided compositional information. The SEM and TEM results indicate that the morphology and crystalline nature of the zirconia varies as a result of the existence of a thermal gradient. The EDS results show that the majority of the impurities segregates to the silica phase of the PDZ.

  2. 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...

  3. Nucleon-XcJ Dissociation Cross Sections

    Institute of Scientific and Technical Information of China (English)

    冯又层; 许晓明; 周代翠

    2002-01-01

    Nucleon-XcJ dissociation cross sections are calculated in a constituent interexchange model in which quark-quark potential is derived from the Buchmüller-Tye quark-anti-quark potential. These new cross sections for dominant reaction channels depend on the centre-of-mass energy of the nucleon and the charmonium.

  4. Coherent dissociation of relativistic 12N nuclei

    International Nuclear Information System (INIS)

    The dissociation of relativistic 12N nuclei having a momentum of 2 GeV/c per nucleon and undergoing the most peripheral interactions in a track emulsion is studied. The picture of charged topology of product ensembles of relativistic fragments and special features of their angular distributions are presented

  5. 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 whi

  6. CAPTURED End Evaluation Synthesis Report

    NARCIS (Netherlands)

    Brouwers, J.H.A.M.

    2012-01-01

    This report provides the findings of the Synthesis Study of the CAPTURED Evaluation and is produced as part of the overall CAPTURED End Evaluation. After five years of support by the CAPTURED project the three CAPTURED partners have achieved commendable results. Ten lessons learned are formulated th

  7. Theory of electron capture

    International Nuclear Information System (INIS)

    The historical development of a theoretical model for the electron-capture detector, sometimes called the 'classical' model, is presented and the model as it stands today is described. This is followed by a comparison of the model with experimental data obtained with other techniques since the early development of the theory and finally a section on correlations and predictions is presented. (Auth.)

  8. Use of an intense microwave laser to dissociate a diatomic molecule: Theoretical prediction of dissociation dynamics

    Indian Academy of Sciences (India)

    Amita Wadehra; B M Deb

    2012-01-01

    By employing an intense microwave laser of wavelength 116.65 m with intensities 1 × 1013 and 5 × 1018Wcm−2, respectively, the conclusion is reached theoretically and computationally that it is possible to dissociate the CO molecule, modelled as a Morse oscillator. It is predicted that for above-threshold dissociation (ATD), the molecule should absorb 1044 photons of the given wavelength in order to reach the lowest edge of the vibrational continuum. A consistent analysis of the predicted dissociation process is provided though the time-dependent probability density, dissociation probability, norm, potential function, HHG and ATD spectra, obtained by numerically solving the time-dependent vibrational Schödinger equation.

  9. Ultrafast charge separation in organic photovoltaics enhanced by charge delocalization and vibronically hot exciton dissociation

    CERN Document Server

    Tamura, Hiroyuki

    2013-01-01

    In organic photovoltaics, the mechanism by which free electrons and holes are generated overcoming the Coulomb attraction is a currently much debated topic. To elucidate this mechanism at a molecular level, we carried out a combined electronic structure and quantum dynamical analysis that captures the elementary events from the exciton dissociation to the free carrier generation at polymer/fullerene donor-acceptor heterojunctions. Our calculations show that experimentally observed efficient charge separations can be explained by a combination of two effects: First, the delocalization of charges which substantially reduces the Coulomb barrier, and second, the vibronically hot nature of the charge transfer state which promotes charge dissociation beyond the barrier. These effects facilitate an ultrafast charge separation even at low-band-offset heterojunctions.

  10. Thermal dissociation behavior and dissociation enthalpies of methane-carbon dioxide mixed hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, T.H.; Kneafsey, T.J.; Rees, E.V.L.

    2011-02-15

    Replacement of methane with carbon dioxide in hydrate has been proposed as a strategy for geologic sequestration of carbon dioxide (CO{sub 2}) and/or production of methane (CH{sub 4}) from natural hydrate deposits. This replacement strategy requires a better understanding of the thermodynamic characteristics of binary mixtures of CH{sub 4} and CO{sub 2} hydrate (CH{sub 4}-CO{sub 2} mixed hydrates), as well as thermophysical property changes during gas exchange. This study explores the thermal dissociation behavior and dissociation enthalpies of CH{sub 4}-CO{sub 2} mixed hydrates. We prepared CH{sub 4}-CO{sub 2} mixed hydrate samples from two different, well-defined gas mixtures. During thermal dissociation of a CH{sub 4}-CO{sub 2} mixed hydrate sample, gas samples from the head space were periodically collected and analyzed using gas chromatography. The changes in CH{sub 4}-CO{sub 2} compositions in both the vapor phase and hydrate phase during dissociation were estimated based on the gas chromatography measurements. It was found that the CO{sub 2} concentration in the vapor phase became richer during dissociation because the initial hydrate composition contained relatively more CO{sub 2} than the vapor phase. The composition change in the vapor phase during hydrate dissociation affected the dissociation pressure and temperature; the richer CO{sub 2} in the vapor phase led to a lower dissociation pressure. Furthermore, the increase in CO{sub 2} concentration in the vapor phase enriched the hydrate in CO{sub 2}. The dissociation enthalpy of the CH{sub 4}-CO{sub 2} mixed hydrate was computed by fitting the Clausius-Clapeyron equation to the pressure-temperature (PT) trace of a dissociation test. It was observed that the dissociation enthalpy of the CH{sub 4}-CO{sub 2} mixed hydrate lays between the limiting values of pure CH{sub 4} hydrate and CO{sub 2} hydrate, increasing with the CO{sub 2} fraction in the hydrate phase.

  11. Psychobiological characteristics of dissociative identity disorder : A symptom provocation study

    NARCIS (Netherlands)

    Reinders, A. A. T. Simone; Nijenhuis, Ellert R. S.; Quak, Jacqueline; Korf, Jakob; Haaksma, Jaap; Paans, Anne M. J.; Willemsen, Antoon T. M.; den Boer, Johan A.

    2006-01-01

    Background: Dissociative identity disorder (DID) patients function as two or more identities or dissociative identity states (DIS), categorized as 'neutral identity states' (NIS) and 'traumatic identity states' (TIS). NIS inhibit access to traumatic memories thereby enabling daily life functioning.

  12. Direct non-dissociative and dissociative ionization of CO2 by positron impact

    International Nuclear Information System (INIS)

    Detailed measurements of the cross-section for non-dissociative ionization of CO2 are presented and compared with available experimental and theoretical results. An excellent agreement is found with the energy dependence of another experimental determination; however, uncertainties exist over the magnitude. Also presented are the preliminary results for the combined cross-section for direct dissociative ionization of CO2 into O+ or C+

  13. 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. PMID:24377972

  14. 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…

  15. 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.

  16. Gadolinium neutron capture therapy

    International Nuclear Information System (INIS)

    Gadolinium neutron capture therapy makes use of photons and electrons produced by nuclear reactions between gadolinium and lower-energy neutrons which occur within the tumor. The results of our studies have shown that its radiation effect is mostly of low LET and that the electrons are the significant component in the over-all dose. The dose from gadolinium neutron capture reactions does not seem to increase in proportion to the gadolinium concentration, and the Gd-157 concentration of about 100 μg/ml appears most optimal for therapy. Close contact between gadolinium and the cell is not necessarily required for cell inactivation, however, the effect of electrons released from intracellular gadolinium may be significant. Experimental studies on tumor-bearing mice and rabbits have shown that this is a very promising modality though further improvements in gadolinium delivery to tumors are needed. (author)

  17. Supernova electron capture rates

    CERN Document Server

    Martínez-Pinedo, G

    1999-01-01

    We have calculated the Gamow-Teller strength distributions for the ground states and low lying states of several nuclei that play an important role in the precollapse evolution of supernova. The calculations reproduce the experimental GT distributions nicely. The GT distribution are used to calculate electron capture rates for typical presupernova conditions. The computed rates are noticeably smaller than the presently adopted rates. The possible implications for the supernova evolution are discussed.

  18. Inland capture fisheries

    OpenAIRE

    Welcomme, Robin L.; Cowx, Ian G.; Coates, David; Béné, Christophe; Funge-Smith, Simon; Halls, Ashley; Lorenzen, Kai

    2010-01-01

    The reported annual yield from inland capture fisheries in 2008 was over 10 million tonnes, although real catches are probably considerably higher than this. Inland fisheries are extremely complex, and in many cases poorly understood. The numerous water bodies and small rivers are inhabited by a wide range of species and several types of fisher community with diversified livelihood strategies for whom inland fisheries are extremely important. Many drivers affect the fisheries, including inter...

  19. Laser capture microscopy

    OpenAIRE

    Curran, S.; McKay, J A; McLeod, H L; Murray, G I

    2000-01-01

    Human tissues are composed of complex admixtures of different cell types and their biologically meaningful analysis necessitates the procurement of pure samples of the cells of interest. Many approaches have been used in attempts to overcome this difficulty, including a variety of microdissection methods. This review concerns a recent advance in microdissection techniques, namely laser capture microdissection (LCM). The principle underlying this technique is outlined, and practical issues per...

  20. Study of the 17Ne Coulomb dissociation process and its role for the rp process of nucleosynthesis

    International Nuclear Information System (INIS)

    The study of 17Ne Coulomb dissociation process gives us a possibility to study the time-reversed reaction 15O(2p,γ)17Ne, with the detailed balance theorem. This reaction could serve as a bypass of 15O waiting point during the rp process, and move the initial CNO material towards heavier nuclei. The two-proton capture can proceed sequentially or directly from the three-body continuum. And the reaction rate can be enhanced by a few orders of magnitude by taking the three-body continuum into account. The Coulomb dissociation method is the one way to experimentally determine the three-body radiative capture cross section, which is needed to verify theoretical calculations, and which was not experimentally determined yet. The experiment has been performed at the LAND/R3B setup at GSI.

  1. Three-body dissociations: The photodissociation of dimethyl sulfoxide at 193 nm

    Energy Technology Data Exchange (ETDEWEB)

    Blank, D.A.; North, S.W.; Stranges, D. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    When a molecule with two equivalent chemical bonds is excited above the threshold for dissociation of both bonds, how the rupture of the two bonds is temporally coupled becomes a salient question. Following absorption at 193 nm dimethyl sulfoxide (CH{sub 3}SOCH{sub 3}) contains enough energy to rupture both C-S bonds. This can happen in a stepwise (reaction 1) or concerted (reaction 2) fashion where the authors use rotation of the SOCH{sub 3} intermediate prior to dissociation to define a stepwise dissociation: (1) CH{sub 3}SOCH{sub 3} {r_arrow} 2CH{sub 3} + SO; (2a) CH{sub 3}SOCH{sub 3} {r_arrow} CH{sub 3} + SOCH{sub 3}; and (2b) SOCH{sub 3} {r_arrow} SO + CH{sub 3}. Recently, the dissociation of dimethyl sulfoxide following absorption at 193 nm was suggested to involve simultaneous cleavage of both C-S bonds on an excited electronic surface. This conclusion was inferred from laser induced fluorescence (LIF) and resonant multiphoton ionization (2+1 REMPI) measurements of the internal energy content in the CH{sub 3} and SO photoproducts and a near unity quantum yield measured for SO. Since this type of concerted three body dissociation is very interesting and a rather rare event in photodissociation dynamics, the authors chose to investigate this system using the technique of photofragment translational spectroscopy at beamline 9.0.2.1. The soft photoionization provided by the VUV undulator radiation allowed the authors to probe the SOCH{sub 3} intermediate which had not been previously observed and provided good evidence that the dissociation of dimethyl sulfoxide primarily proceeds via a two step dissociation, reaction 2.

  2. Assessment of dissociation among combat-exposed soldiers with and without posttraumatic stress disorder

    Directory of Open Access Journals (Sweden)

    Barbaros Özdemir

    2015-04-01

    Full Text Available Background: Dissociation is a disruption of and/or discontinuity in the normal, subjective integration of one or more aspects of psychological functioning, including memory, identity, consciousness, perception, and motor control. A limited number of studies investigated combat-related dissociation. Objective: The primary aim of this study was to evaluate the relationship between dissociative symptoms and combat-related trauma. Method: This study included 184 individuals, including 84 patients who were exposed to combat and diagnosed with posttraumatic stress disorder (PTSD (Group I, 50 subjects who were exposed to combat but were not diagnosed with PTSD (Group II, and 50 healthy subjects without combat exposure (Group III. The participants were evaluated using the Dissociative Experiences Scale (DES to determine their total and sub-factor (i.e., amnesia, depersonalization/derealization, and absorption dissociative symptom levels. In addition, Group I and Group II were compared with respect to the relationship between physical injury and DES scores. Results: The mean DES scores (i.e., total and sub-factors of Group I were higher than those of Group II (p30 was highest in Group I, followed by Group II and Group III. When we compared combat-exposed subjects with high total DES scores, Group I had higher scores than Group II. In contrast, no relationship between the presence of bodily injury and total DES scores could be demonstrated. In addition, our results demonstrated that high depersonalization/derealization factor scores were correlated with bodily injury in PTSD patients. A similar relationship was found between high absorption factor scores and bodily injury for Group II. Conclusions: Our results demonstrated that the level of dissociation was significantly higher in subjects with combat-related PTSD than in subjects without combat-related PTSD. In addition, combat-exposed subjects without PTSD also had higher dissociation levels than

  3. On the dissociation pathways of nitrobenzene

    Science.gov (United States)

    Kosmidis, C.; Ledingham, K. W. D.; Clark, A.; Marshall, A.; Jennings, R.; Sander, J.; Singhal, R. P.

    1994-08-01

    The fragmentation of nitrobenzene has been studied in the wavelength range 225-275 nm using a single dye laser, frequency doubled, in conjunction with a time-of-flight (TOF) mass spectrometer. The parent (C6H5NO2+), nitrosobenzene (C6H5NO+), phenoxy (C6H5O+) and phenyl (C6H5+) ions were all observed in addition to many other lighter daughter fragments. The formation of the nitrobenzene, phenoxy and phenyl ions are all explained invoking pathways where dissociation of the parent molecule from an excited state takes place first, followed by ionization after the absorption of further photons (DI) by the fragmented neutrals. Ionization of the parent molecule to states which are dissociative (ID) can explain the increase in the production of phenyl ions at wavelengths shorter than 230 nm.

  4. Multiphoton dissociative ionization of molecular deuterium

    International Nuclear Information System (INIS)

    The kinetic energy spectra of deuterium ions produced from D2 arising from collision-free subpicosecond irradiation at 248 nm with intensities spanning the 10/sup 13/--10/sup 16/-W/cm2 range have been measured by time-of-flight analysis. The behaviors of the kinetic energy distributions of the fragments and the relative abundances of atomic (D+) and molecular (D2+) ions reveal the presence of two mechanisms of multiphoton dissociative ionization. Calibration of the energy scale for D+ is facilitated by comparison with He/sup 2+/. For intensities in the 10/sup 13/--10/sup 15/-W/cm2 region, intermediate three-photon resonances and the optical Stark shift play important roles. At an intensity /similar to/0/sup 16/ W/cm2, a direct transition from the molecular ground state to the dissociative ionic level appears as a significant channel. No evidence of direct double ionization was observed

  5. The charmonium dissociation in an "anomalous wind"

    CERN Document Server

    Sadofyev, Andrey V

    2016-01-01

    We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries ``anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the ``anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the ``anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and {\\it qualitative} difference between anomalous effects on the charmonium color screening length which are {\\it model-dependent} and those on the heavy quark drag force which are fixed by the second law of thermodynamics. We speculate on the possible charmonium dissociation induced by chiral anomaly in heavy ion collisions.

  6. The charmonium dissociation in an "anomalous wind"

    Science.gov (United States)

    Sadofyev, Andrey V.; Yin, Yi

    2016-01-01

    We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries "anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the "anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the "anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and qualitative difference between anomalous effects on the charmonium color screening length which are model-dependent and those on the heavy quark drag force which are fixed by the second law of thermodynamics. We speculate on the possible charmonium dissociation induced by the chiral anomaly in heavy ion collisions.

  7. Coulomb dissociation of $^{20,21}$N

    CERN Document Server

    Röder, Marko; 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; Gernhäuser, Roman; Göbel, Kathrin; Golubev, Pavel; Diaz, Diego Gonzalez; Hagdahl, Julius; Heftrich, Tanja; Heil, Michael; Heine, Marcel; Heinz, Andreas; Henriques, Ana; Holl, Matthias; Ickert, G; Ignatov, Alexander; Jakobsson, Bo; Johansson, Hakan; Jonson, Björn; Kalantar-Nayestanaki, Nasser; Kanungo, Rituparna; Kelic-Heil, Aleksandra; Knöbel, Ronja; Kröll, Thorsten; Krücken, Reiner; Kurcewicz, J; Kurz, Nikolaus; Labiche, Marc; Langer, Christoph; Bleis, Tudi Le; Lemmon, Roy; Lepyoshkina, Olga; Lindberg, Simon; Machado, Jorge; Marganiec, Justyna; Caro, Magdalena Mostazo; Movsesyan, Alina; Najafi, Mohammad Ali; Nilsson, Thomas; Nociforo, Chiara; Panin, Valerii; Paschalis, Stefanos; Perea, Angel; Petri, Marina; Pietri, S; Plag, Ralf; Prochazka, A; Rahaman, Md Anisur; Rastrepina, Ganna; Reifarth, Rene; Ribeiro, Guillermo; Ricciardi, M Valentina; Rigollet, Catherine; Riisager, Karsten; Rossi, Dominic; Saez, Jose Sanchez del Rio; Savran, Deniz; Scheit, Heiko; Simon, Haik; Sorlin, Olivier; Stoica, V; Streicher, Branislav; Taylor, Jon; Tengblad, Olof; Terashima, Satoru; Thies, Ronja; Togano, Yasuhiro; Uberseder, Ethan; Van de Walle, J; Velho, Paulo; Volkov, Vasily; Wagner, Andreas; Wamers, Felix; Weick, Helmut; Weigand, Mario; Wheldon, Carl; Wilson, G; Wimmer, Christine; Winfield, J S; Woods, Philip; Yakorev, Dmitry; Zhukov, Mikhail; Zilges, Andreas; Zuber, Kai

    2016-01-01

    Neutron-rich light nuclei and their reactions play an important role for the creation of chemical elements. Here, data from a Coulomb dissociation experiment on $^{20,21}$N are reported. Relativistic $^{20,21}$N 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 $^{19}\\mathrm{N}(\\mathrm{n},\\gamma)^{20}\\mathrm{N}$ and $^{20}\\mathrm{N}(\\mathrm{n},\\gamma)^{21}\\mathrm{N}$ excitation functions and thermonuclear reaction rates have been determined. The $^{19}\\mathrm{N}(\\mathrm{n},\\gamma)^{20}\\mathrm{N}$ rate is up to a factor of 5 higher at $T<1$\\,GK with respect to previous theoretical calculations, leading to a 10\\,\\% decrease in the predicted fluorine abundance.

  8. New aspects of the neutron capture in light nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Mengoni, A. [Institute of Physical and Chemical Research, Wako, Saitama (Japan)

    1997-03-01

    Several neutron capture cross sections of light nuclei (A {<=} 40) for neutron energies up to the MeV region have been recently calculated. Examples are (target nuclei): {sup 12}C, {sup 13}C, {sup 16}O and {sup 10}Be. The results of these calculations will be shown together with a comparison with the most recent experimental data. In the case of n + {sup 10}Be case, the cross section of the inverse process (Coulomb dissociation of {sup 11}Be) is considered and compared with the measurement. A discussion on the relevant nuclear structure information required for the evaluation of nuclear data of light nuclei is given. (author)

  9. Use of Computed X-ray Tomographic Data for Analyzing the Thermodynamics of a Dissociating Porous Sand/Hydrate Mixture

    Science.gov (United States)

    Freifeld, Barry M.; Kneafsey, Timothy J.; Tomutsa, Liviu; Stern, Laura A.; Kirby, Stephen H.

    2002-02-28

    X-ray computed tomography (CT) is a method that has been used extensively in laboratory experiments for measuring rock properties and fluid transport behavior. More recently, CT scanning has been applied successfully to detect the presence and study the behavior of naturally occurring hydrates. In this study, we used a modified medical CT scanner to image and analyze the progression of a dissociation front in a synthetic methane hydrate/sand mixture. The sample was initially scanned under conditions at which the hydrate is stable (atmospheric pressure and liquid nitrogen temperature, 77 K). The end of the sample holder was then exposed to the ambient air, and the core was continuously scanned as dissociation occurred in response to the rising temperature. CT imaging captured the advancing dissociation front clearly and accurately. The evolved gas volume was monitored as a function of time. Measured by CT, the advancing hydrate dissociation front was modeled as a thermal conduction problem explicitly incorporating the enthalpy of dissociation, using the Stefan moving-boundary-value approach. The assumptions needed to perform the analysis consisted of temperatures at the model boundaries. The estimated value for thermal conductivity of 2.6 W/m K for the remaining water ice/sand mixture is higher than expected based on conduction alone; this high value may represent a lumped parameter that incorporates the processes of heat conduction, methane gas convection, and any kinetic effects that occur during dissociation. The technique presented here has broad implications for future laboratory and field testing that incorporates geophysical techniques to monitor gas hydrate dissociation.

  10. Lebanon and Syria: between dissociation and spillover

    OpenAIRE

    Javier Lion Bustillo

    2014-01-01

    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...

  11. Dissociations between developmental dyslexias and attention deficits

    OpenAIRE

    Limor eLukov; Naama eFriedmann; Lilach eShalev; Lilach eKhentov-Kraus; Nir eShalev; Rakefet eLorber; Revital eGuggenheim

    2015-01-01

    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 o...

  12. Long-term outcome and prognosis of dissociative disorder with onset in childhood or adolescence

    Directory of Open Access Journals (Sweden)

    Wewetzer Christoph

    2008-07-01

    Full Text Available Abstract Background In the majority of cases short-term treatment outcome of juvenile dissociative disorder is rather favourable. In contrast, the long-term course seems to be less positive, but meaningful results are still fragmentary. The aim of this follow-up study is to bridge this gap to some extent describing the long-term outcome of juvenile dissociative disorder in a clinical sample. To our knowledge there is no comparable other long-term follow-up study which is based on a case definition according to actual classification systems using standardized interviews for individual assessment of the patients at the time of follow-up. Methods The total study group was made up of all patients treated for dissociative disorder at our department for child and adolescent psychiatry between 1983 and 1992 (N = 62. Two of these former patients committed suicide during the follow-up period (3%. We got information on the clinical course of 27 former patients (44%. 17 out of these 27 former patients were female (63%. The mean age of onset of dissociative disorder was11.7 years and the mean follow-up time was 12.4 years. Most of the patients were reassessed personally (n = 23 at a mean age of 24.8 years using structured interviews covering dissociative disorders, other Axis I disorders and personality disorders (Heidelberg Dissociation Inventory HDI; Expert System for Diagnosing Mental Disorders, DIA-X; Structured Clinical Interview for DSM-IV, SCID-II. Social adjustment was assessed by a semi-structured interview and by patient self report (Social Adjustment Scale – Self Report, SAS-SR. Psychosocial outcome variables were additionally assessed in 36 healthy controls (67% female, mean age = 22.9 years. Results At the time of follow-up investigation 82.6% of the patients met the criteria for some form of psychiatric disorder, while 26.1% were still suffering from dissociative disorder. A total of 56.5% presented with an Axis I disorder (especially

  13. Stability evaluation of hydrate-bearing sediments during thermally-driven hydrate dissociation

    Science.gov (United States)

    Kwon, T.; Cho, G.; Santamarina, J.; Kim, H.; Lee, J.

    2009-12-01

    Hydrate-bearing sediments may destabilize spontaneously as part of geological processes, unavoidably during petroleum drilling/production operations, or intentionally as part of gas extraction from the hydrate itself. In all cases, high pore fluid pressure generation is anticipated during hydrate dissociation. This study examined how thermal changes destabilize gas hydrate-bearing sediments. First, an analytical formulation was derived for predicting fluid pressure evolution in hydrate-bearing sediments subjected to thermal stimulation without mass transfer. The formulation captures the self-preservation behavior, calculates the hydrate and free gas quantities during dissociation, considering effective stress-controlled sediment compressibility and gas solubility in aqueous phase. Pore fluid pressure generation is proportional to the initial hydrate fraction and the sediment bulk stiffness; is inversely proportional to the initial gas fraction and gas solubility; and is limited by changes in effective stress that cause the failure of the sediment. Second, the analytical formulation for hydrate dissociation was incorporated as a user-defined function into a verified finite difference code (FLAC2D). The underlying physical processes of hydrate-bearing sediments, including hydrate dissociation, self-preservation, pore pressure evolution, gas dissolution, and sediment volume expansion, were coupled with the thermal conduction, pore fluid flow, and mechanical response of sediments. We conducted the simulations for a duration of 20 years, assuming a constant-temperature wellbore transferred heat to the surrounding hydrate-bearing sediments, resulting in dissociation of methane hydrate in the well vicinity. The model predicted dissociation-induced excess pore fluid pressures which resulted in a large volume expansion and plastic deformation of the sediments. Furthermore, when the critical stress was reached, localized shear failure of the sediment around the borehole was

  14. The infrared multiphoton dissociation of three nitrolkanes

    Science.gov (United States)

    Wodtke, A. M.; Hintsa, E. J.; Lee, Y. T.

    1986-01-01

    Infrared multiphoton dissociation in a molecular beam has been studied in order to elucidate the collision free, 'thermal' chemistry and dynamics of nitromethane, nitroethane and 2-nitropropane. The isomerization of CH3NO2 to CH3ONO was observed by detecting the CH3O and NO products from the dissociation of the very internally hot, isomerized nitromethane. A novel application of RRKM theory was used to estimate the barrier height to isomerization at 55.5 kcal/mol. The barrier height determination method was tested and found to give excellent results by applying it to the determintaion of the barrier height to HONO elimination from nitroethane, a value which is well known from activation energy measurements. The method was then applied to the case of HONO elimination from 2-nitropropane and it appears that there is good to believe that the barrier height is 3-5 kcal/mol lower in 2-nitropropane than in nitroethane. The success of this method for determining barrier heights shows how a microscopic molecular beam experiment, using infrared multiphoton dissociation where the concept of temperature has no place, can be quantitatively related to pyrolysis experiments which are conducted under collisional, thermal conditions and measure phenomenological quantities such as activation energies.

  15. Dissociative recombination of small molecular ions

    International Nuclear Information System (INIS)

    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+, O2+ and N2+ is presented and in chapter V the dissociative recombination for N2H+ and N2D+ 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.)

  16. Gas Hydrate Dissociation in the Ocean

    Science.gov (United States)

    Conroy, Devin; Smith, Stefan Llewellyn

    2006-11-01

    Methane gas is known to exist in extremely large quantities below the sea floor in the sediment of the deep and cold oceanic and in permafrost regions. Due to the large hydrostatic pressure and cool temperatures the gas reacts with the surrounding water to form a crystalline substance known as a gas hydrate. The fate of these reserves is very important to climate on earth because methane is a much more efficient greenhouse gas then carbon dioxide. The dissociation process in general can occur by either a decrease in pressure or an increase in temperature. In this study we concentrate on the latter. Once the hydrate dissociates, water and free gas remain above the phase boundary, occupying a larger volume than the original solid, and are be transported through the sediment. We have modeled this physical mechanism using volume averaged equations in a porous medium with a coupled two-phase flow. The movement of the phase boundary, which is proportional to the rate of heat transfer to this interface, is modeled as a Stefan type melting problem. The resultant governing equations are solved numerically, using a front fixing method to fix the phase boundary, to determine the rate of gas flux through the sediment and the dissociation rate.

  17. 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...

  18. Nonequilibrium dissociation mechanisms in low temperature nitrogen and carbon monoxide plasmas

    International Nuclear Information System (INIS)

    Highlights: • The role of vibrational excitation in affecting N2 dissociation is put in evidence. • Calculations with new complete sets of e-N2 cross sections have been performed. • Vibrational mechanism dominates e-N2 dissociation for E/N < 50 Td. • Vibrational and electron dissociation mechanisms are competitive for E/N > 50 Td. - Abstract: The role of vibrational excitation in affecting the dissociation under discharge conditions characterized by reduced electric field E/N ⩽ 80 Td has been investigated in N2. The kinetic calculations have been performed using a self-consistent approach, solving at the same time the master equation for the composition and the distribution of internal states (vibrational and electronic) and the Boltzmann equation for the electron energy distribution function. The results show that vibrational mechanisms involving heavy particle excited states dominate electron impact dissociation mechanisms involving the whole vibrational ladder for E/N < 50 Td, the two mechanisms being competitive for E/N > 50 Td

  19. Mass fractionation of noble gases in synthetic methane hydrate: Implications for naturally occurring gas hydrate dissociation

    Science.gov (United States)

    Hunt, Andrew G.; Stern, Laura; Pohlman, John W.; Ruppel, Carolyn; Moscati, Richard J.; Landis, Gary P.

    2013-01-01

    As a consequence of contemporary or longer term (since 15 ka) climate warming, gas hydrates in some settings may presently be dissociating and releasing methane and other gases to the ocean-atmosphere system. A key challenge in assessing the impact of dissociating gas hydrates on global atmospheric methane is the lack of a technique able to distinguish between methane recently released from gas hydrates and methane emitted from leaky thermogenic reservoirs, shallow sediments (some newly thawed), coal beds, and other sources. Carbon and deuterium stable isotopic fractionation during methane formation provides a first-order constraint on the processes (microbial or thermogenic) of methane generation. However, because gas hydrate formation and dissociation do not cause significant isotopic fractionation, a stable isotope-based hydrate-source determination is not possible. Here, we investigate patterns of mass-dependent noble gas fractionation within the gas hydrate lattice to fingerprint methane released from gas hydrates. Starting with synthetic gas hydrate formed under laboratory conditions, we document complex noble gas fractionation patterns in the gases liberated during dissociation and explore the effects of aging and storage (e.g., in liquid nitrogen), as well as sampling and preservation procedures. The laboratory results confirm a unique noble gas fractionation pattern for gas hydrates, one that shows promise in evaluating modern natural gas seeps for a signature associated with gas hydrate dissociation.

  20. Precious metal-free catalyst for purification of automotive exhausts: NO dissociation on Cu oxide surfaces

    Science.gov (United States)

    Kasai, Hideaki; Padama, Allan Abraham; Moreno, Joaquin Lorenzo

    2014-03-01

    The dissociation of NOx molecule on catalysts is the rate-limiting step for its reduction process and is the subject of recent investigations related to exhaust gas purification. Three-way catalysts which are composed of Rh, Pd and Pt, are known to work well for such purpose; however, their expensive cost hinders their applicability. In this work, Computational Materials Design based on density functional theory was employed to test the efficiency of Cu-based catalysts for NO dissociation. It was found that the dissociation path of NO on Cu-terminated Cu2O(111) and CuO(110) surfaces is comparable with Rh(111). This is attributed to the modified electronic structure of the surface Cu atoms of Cu oxides in comparison with Cu(111). The calculated NO dissociation barriers are lower and the binding energies of co-adsorbed N and O atoms are weaker on Cu oxides than on Rh(111), which is favorable for subsequent reactions. Our experimental collaborator had also verified that Cu oxides can be better catalysts than Rh, Pd and Pt for the purification of exhaust gases. The details of this work and the oxidation of CO in the presence of dissociated NO will be discussed in the meeting.

  1. Lunar Sulfur Capture System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Lunar Sulfur Capture System (LSCS) is an innovative method to capture greater than 90 percent of sulfur gases evolved during thermal treatment of lunar soils....

  2. Multiphonon capture processes in self-assembled quantum dots

    DEFF Research Database (Denmark)

    Magnúsdóttir, Ingibjörg; Uskov, A.; Bischoff, Svend;

    2001-01-01

    We investigate capture of carriers from states in the continuous part of the energy spectrum into the discrete states of self-assembled InAs/GaAs QDs via emission of one or two phonons. We are not aware of any other investigations of two-phonon mediated capture processes in QDs, but we show that...

  3. 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. PMID:26738691

  4. Ab initio calculations of dissociative attachment and dissociative recombination of electrons and polyatomic species

    Science.gov (United States)

    Haxton, Daniel

    2009-05-01

    Interactions of free electrons with neutral and positively charged molecular species play a role in various physical systems. In interstellar space, reactions such as dissociative recombination determine the balance of various charged and neutral species. In a laboratory equipped with an apparatus like a COLTRIMS device, the dissociative attachment process can be used as a microscope to study polyatomic molecular dynamics. We discuss the theoretical and numerical methods used to calculate dissociative attachment and dissociative recombination of electrons with larger molecules from first principles. Studies using these methods are complimentary to other methods that yield more approximate reaction rates at greatly lesser numerical cost; they may yield precise information about the dissociation dynamics, product distribution, and differential cross section that approximate methods cannot. We discuss calculations performed to date on the target species H2O, NO2, and LiH2^+. We discuss the scaling of our numerical methods with the number of atoms, and the prospects of applying them to tetra-atomics.

  5. Site selectivity of specific reaction steps important for catalysis:CO dissociation on ruthenium surfaces

    OpenAIRE

    Nielsen, Kenneth; Nielsen, Jane Hvolbæk

    2011-01-01

    This thesis presents the results of two dierent projects, both focused on catalysis. The main part is about the investigation of the structure sensitivity of the CO dissociation reaction with STM on a Ru(0 1 54) single crystal and the second part concerns the STM structure study of the Bi/Pt(111) overlayer system. In the STM study of the structure sensitivity of the CO dissociation reaction on the Ru(0 1 54) sample, it was determined that after cooling the sample from 700K to 400K in 10-8Torr...

  6. Hemispheric association and dissociation of voice and speech information processing in stroke.

    Science.gov (United States)

    Jones, Anna B; Farrall, Andrew J; Belin, Pascal; Pernet, Cyril R

    2015-10-01

    As we listen to someone speaking, we extract both linguistic and non-linguistic information. Knowing how these two sets of information are processed in the brain is fundamental for the general understanding of social communication, speech recognition and therapy of language impairments. We investigated the pattern of performances in phoneme versus gender categorization in left and right hemisphere stroke patients, and found an anatomo-functional dissociation in the right frontal cortex, establishing a new syndrome in voice discrimination abilities. In addition, phoneme and gender performances were most often associated than dissociated in the left hemisphere patients, suggesting a common neural underpinnings. PMID:26247409

  7. The Dissociation Energies of CH4 and C2H2 Revisited

    Science.gov (United States)

    Partridge, Harry; Bauschlicher, Charles W., Jr.; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    The bond dissociation energies of CH4 and C2H2 and their fragments are investigated using basis set extrapolations and high levels of correlation. The computed bond dissociation energies (D(sub e)) are accurate to within 0.2 kcal/mol. The agreement with the experimental (D(sub 0)) values is excellent if we assume that the zero-point energy of C2H is 9.18 kcal/mol. The effect of core (1s) correlation on the bond dissociation energies of C-H bonds is shown to vary from 0.2 to 0.7 kcal/mol and that for C-C bonds varies from 0.4 to 2.2 kcal/mol.

  8. In Situ Raman Spectroscopy Study on Dissociation of Methane at High Temperatures and at High Pressures

    Institute of Scientific and Technical Information of China (English)

    CHEN Jin-Yang; JIN Lu-Jiang; DONG Jun-Ping; ZHENG Hai-Fei

    2008-01-01

    We investigate the stability and dissociation of methane,which is the most abundant organic molecule in the universe,using diamond anvil cell(DAC)with in situ Raman spectroscopy up to 903K and 21GPa.At the temperatures of 793 and 723K and the corresponding pressures of 16.15 and 20.30 GPa,methane dissociates to very high,methane remains stability up to the highest temperature of 903 K of the work.The four symmetricC-H bonds of methane split at high temperatures and at high pressures,and there is at least one phase transitionof crystalline symmetry from face centred cubic (fce) to hexagonal dose packed (hcp) before dissociation.

  9. Methane Hydrate Formation and Dissociation in the Presence of Silica Sand and Bentonite Clay

    Directory of Open Access Journals (Sweden)

    Kumar Saw V.

    2015-11-01

    Full Text Available The formation and dissociation of methane hydrates in a porous media containing silica sand of different sizes and bentonite clay were studied in the presence of synthetic seawater with 3.55 wt% salinity. The phase equilibrium of methane hydrate under different experimental conditions was investigated. The effects of the particle size of silica sand as well as a mixture of bentonite clay and silica sand on methane hydrate formation and its dissociation were studied. The kinetics of hydrate formation was studied under different subcooling conditions to observe its effects on the induction time of hydrate formation. The amount of methane gas encapsulated in hydrate was computed using a real gas equation. The Clausius-Clapeyron equation is used to estimate the enthalpy of hydrate dissociation with measured phase equilibrium data.

  10. Dissociation dynamics of ethylene molecules on a Ni cluster using ab initio molecular dynamics simulations

    Science.gov (United States)

    Shimamura, K.; Shibuta, Y.; Ohmura, S.; Arifin, R.; Shimojo, F.

    2016-04-01

    The atomistic mechanism of dissociative adsorption of ethylene molecules on a Ni cluster is investigated by ab initio molecular-dynamics simulations. The activation free energy to dehydrogenate an ethylene molecule on the Ni cluster and the corresponding reaction rate is estimated. A remarkable finding is that the adsorption energy of ethylene molecules on the Ni cluster is considerably larger than the activation free energy, which explains why the actual reaction rate is faster than the value estimated based on only the activation free energy. It is also found from the dynamic simulations that hydrogen molecules and an ethane molecule are formed from the dissociated hydrogen atoms, whereas some exist as single atoms on the surface or in the interior of the Ni cluster. On the other hand, the dissociation of the C-C bonds of ethylene molecules is not observed. On the basis of these simulation results, the nature of the initial stage of carbon nanotube growth is discussed.

  11. Model, First-Principle Calculation of Ammonia Dissociation on Si(100 Surface. Importance of Proton Tunneling

    Directory of Open Access Journals (Sweden)

    Marek Z. Zgierski

    2003-06-01

    Full Text Available Abstract: The dissociation of an ammonia molecule on a cluster of Si atoms simulating the 100 silicon crystal structure with two Si dimers has been investigated by means of the DFT and an approximate instanton methods. The model corresponds to the low coverage limit of the surface. Absolute rate constants of two different dissociation paths are evaluated together with deuterium isotope effects. It is demonstrated that, even at room temperatures, the process is dominated by tunneling and that dissociation to a silicon atom of the adjacent dimer, rather than a silicon within the same dimer, is the prevailing mechanism. This leads to creation of a metastable structure which will slowly decay through a two-step hydrogen atom migration towards the absolute minimum on the potential energy surface corresponding to the NH2 group and the hydrogen atom residing in the same dimer.

  12. Dissociation dynamics of ethylene molecules on a Ni cluster using ab initio molecular dynamics simulations

    International Nuclear Information System (INIS)

    The atomistic mechanism of dissociative adsorption of ethylene molecules on a Ni cluster is investigated by ab initio molecular-dynamics simulations. The activation free energy to dehydrogenate an ethylene molecule on the Ni cluster and the corresponding reaction rate is estimated. A remarkable finding is that the adsorption energy of ethylene molecules on the Ni cluster is considerably larger than the activation free energy, which explains why the actual reaction rate is faster than the value estimated based on only the activation free energy. It is also found from the dynamic simulations that hydrogen molecules and an ethane molecule are formed from the dissociated hydrogen atoms, whereas some exist as single atoms on the surface or in the interior of the Ni cluster. On the other hand, the dissociation of the C-C bonds of ethylene molecules is not observed. On the basis of these simulation results, the nature of the initial stage of carbon nanotube growth is discussed. (paper)

  13. MMPI-2 Item Endorsements in Dissociative Identity Disorder vs. Simulators.

    Science.gov (United States)

    Brand, Bethany L; Chasson, Gregory S; Palermo, Cori A; Donato, Frank M; Rhodes, Kyle P; Voorhees, Emily F

    2016-03-01

    Elevated scores on some MMPI-2 (Minnesota Multiphasic Inventory-2) validity scales are common among patients with dissociative identity disorder (DID), which raises questions about the validity of their responses. Such patients show elevated scores on atypical answers (F), F-psychopathology (Fp), atypical answers in the second half of the test (FB), schizophrenia (Sc), and depression (D) scales, with Fp showing the greatest utility in distinguishing them from coached and uncoached DID simulators. In the current study, we investigated the items on the MMPI-2 F, Fp, FB, Sc, and D scales that were most and least commonly endorsed by participants with DID in our 2014 study and compared these responses with those of coached and uncoached DID simulators. The comparisons revealed that patients with DID most frequently endorsed items related to dissociation, trauma, depression, fearfulness, conflict within family, and self-destructiveness. The coached group more successfully imitated item endorsements of the DID group than did the uncoached group. However, both simulating groups, especially the uncoached group, frequently endorsed items that were uncommonly endorsed by the DID group. The uncoached group endorsed items consistent with popular media portrayals of people with DID being violent, delusional, and unlawful. These results suggest that item endorsement patterns can provide useful information to clinicians making determinations about whether an individual is presenting with DID or feigning. PMID:26944745

  14. Ion Momentum Imaging of Dissociative Electron Attachment to Small Molecules

    Science.gov (United States)

    Fogle, Michael

    2015-09-01

    In recent years, low energy dissociative electron attachment (DEA) interactions have been of interest to varying biological and technological applications. To study the dynamics resulting from DEA, we used an ion-momentum imaging apparatus based on the Cold Target Recoil Ion Momentum Spectroscopy (COLTRIMS) technique in which a molecular beam is crossed by a pulsed electron beam. The beam interaction takes place in a 4 π pulsed electrostatic spectrometer that collects the anion fragments resulting from DEA. The molecular beam is formed by a supersonic expansion which results in a well-localized and cold target. Using this apparatus we have investigated the DEA dynamics for several small molecules: CO2 at the 4 eV shape resonance and the 8 eV Feshbach resonance; N2O at the 2.3 eV shape resonance; HCCH at the 3 eV shape resonance; and CF4 near the 7 eV resonance. An overview of these experimental ion-momentum results will be compared to ab initio electronic structure and fixed-nuclei scattering calculations to gauge the resulting dynamics driven by DEA. In many cases, conical intersections play a pivotal role in driving the dynamics. Some of these systems exhibit non-axial recoil conditions indicative of a bending dynamics in the transitory negative ion state while others exhibit a direct axial recoil dissociation without any bending. This work is supported by the National Science Foundation under Contract NSF-PHYS1404366.

  15. Molecular dynamics studies of the dissociated screw dislocation in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Choudhury, R; Gattinoni, C; Makov, G; De Vita, A [Physics Department, King' s College London, Strand, London WC2R 2LS (United Kingdom)

    2010-02-24

    Characterizing the motion of dislocations through covalent, high Peierls barrier materials is a key problem in materials science, while despite the progress in experimental studies the actual observation of the atomistic behaviour involved in core migration remains limited. We have applied a hybrid embedding scheme to investigate the dissociated screw dislocation in silicon, consisting of two 30 deg. partials separated by a stacking fault ribbon, under the influence of a constant external strain. Our 'learn on the fly' hybrid technique allows us to calculate the forces on atoms in the vicinity of the core region using the tight binding Kwon potential, whilst the remainder of the bulk matrix is treated within a classical approximation. Applying a 5% strain to the dissociated screw dislocation, for a simulation time of 100 ps at a temperature of 600 K, we observe movement of the partials through two different mechanisms: double kink formation and square ring diffusion at the core. Our results suggest that in these conditions, the role of solitons or anti-phase defects in seeding kink formation and subsequent migration is an important one, which should be taken into account in future studies.

  16. Molecular dynamics studies of the dissociated screw dislocation in silicon.

    Science.gov (United States)

    Choudhury, R; Gattinoni, C; Makov, G; De Vita, A

    2010-02-24

    Characterizing the motion of dislocations through covalent, high Peierls barrier materials is a key problem in materials science, while despite the progress in experimental studies the actual observation of the atomistic behaviour involved in core migration remains limited. We have applied a hybrid embedding scheme to investigate the dissociated screw dislocation in silicon, consisting of two 30° partials separated by a stacking fault ribbon, under the influence of a constant external strain. Our 'learn on the fly' hybrid technique allows us to calculate the forces on atoms in the vicinity of the core region using the tight binding Kwon potential, whilst the remainder of the bulk matrix is treated within a classical approximation. Applying a 5% strain to the dissociated screw dislocation, for a simulation time of 100 ps at a temperature of 600 K, we observe movement of the partials through two different mechanisms: double kink formation and square ring diffusion at the core. Our results suggest that in these conditions, the role of solitons or anti-phase defects in seeding kink formation and subsequent migration is an important one, which should be taken into account in future studies. PMID:21386388

  17. Developments in CO2 dissociation using non-equilibrium microwave plasma activation for solar fuels

    NARCIS (Netherlands)

    Bongers, W. A.; Welzel, S.; van den Bekerom, D. C. M.; Frissen, G. F. W. M.; van Rooij, G. J.; Goede, A. P. H.; Graswinckel, M. F.; Groen, P. W. C.; N. den Harder,; van Heemert, B.; Minea, T.; M. C. M. van de Sanden,; Leins, M.; Kopecki, J.; Schulz, A.; Walker, M.

    2015-01-01

    Vortex stabilized microwave plasma conversion of CO2 is considered as promising route for energy efficient dissociation towards CO production. Energy and conversion efficiencies are investigated in scans of reactor pressure, gas flow rate and specific power. Deterioration of efficiencies from 39% to

  18. Trauma-Related Dissociation as a Factor Affecting Musicians' Memory for Music: Some Possible Solutions

    Science.gov (United States)

    Swart, Inette; van Niekerk, Caroline; Hartman, Woltemade

    2010-01-01

    An investigation of the influence of trauma on musicians revealed concentration and memory problems as two of the most common symptoms hampering the performance of affected individuals. In many instances where the causes of these problems were related to trauma sequelae, these could clearly be linked to dissociative symptoms. The following…

  19. Dissociation and Variability of Adult Attachment Dimensions and Early Maladaptive Schemas in Sexual and Violent Offenders

    Science.gov (United States)

    Baker, Elina; Beech, Anthony R.

    2004-01-01

    The aim of this study was to investigate the presence of constructs that may indicate the presence of disorganized attachment style in sexual and violent offenders. Constructs measured were dissociation, variability on self-report measures of attachment style and early maladaptive schemas, and variability in observed behavior. Data on variability…

  20. Recovery of ammonium perrhenate from molybdenite concentrate leaching solutions and its thermic dissociation

    International Nuclear Information System (INIS)

    The recovery of ammonium perrhenate from domestic molybdenite concentrate of direct electrochemical leaching molybdate-rhenate solutions and its dissociation process is investigated in order to obtain pure rhenium thirdoxide. By the method of thermogravimetric and differential-thermic analysis mechanism for perrhenate → bioxide passage is discovered

  1. Early Childhood Bilingualism Leads to Advances in Executive Attention: Dissociating Culture and Language

    Science.gov (United States)

    Yang, Sujin; Yang, Hwajin; Lust, Barbara

    2011-01-01

    This study investigated whether early especially efficient utilization of executive functioning in young bilinguals would transcend potential cultural benefits. To dissociate potential cultural effects from bilingualism, four-year-old U.S. Korean-English bilingual children were compared to three monolingual groups--English and Korean monolinguals…

  2. Dissociation of Subtraction and Multiplication in the Right Parietal Cortex: Evidence from Intraoperative Cortical Electrostimulation

    Science.gov (United States)

    Yu, Xiaodan; Chen, Chuansheng; Pu, Song; Wu, Chenxing; Li, Yongnian; Jiang, Tao; Zhou, Xinlin

    2011-01-01

    Previous research has consistently shown that the left parietal cortex is critical for numerical processing, but the role of the right parietal lobe has been much less clear. This study used the intraoperative cortical electrical stimulation approach to investigate neural dissociation in the right parietal cortex for subtraction and…

  3. 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. PMID:25133142

  4. [Investigation of human papillomavirus prevalence in women in Eskişehir, Turkey by Pap smear, hybrid capture 2 test and consensus real-time polymerase chain reaction and typing with pyrosequencing method].

    Science.gov (United States)

    Aslan, Ferhat Gürkan; Us, Tercan; Kaşifoğlu, Nilgün; Özalp, Sabit Sinan; Akgün, Yurdanur; Öge, Tufan

    2016-01-01

    Human papillomavirus (HPV) infections have a broad range of clinical spectrum from subclinical or asymptomatic infection to anogenital carcinoma. The detection of HPV-DNA and determination of the risk groups in cervical cancer (CC) screening is very important because CC is considered to be a preventable illness which is the third most common cancer type of women in the world. The aims of this study were to investigate the presence of HPV-DNA in women by two different molecular methods and to compare their results together with the results of cytology, in Eskişehir, Central Anatolia, Turkey. A total of 1081 women aged between 30-65 years, who applied to Eskişehir Early Diagnosis, Screening and Training of Cancer Center (KETEM) for screening were included in the study. Three separate cervical samples were collected simultaneously from the participants for cytologic examination and molecular studies. In the first step of the study, all cervical samples were investigated for the presence of HPV-DNA by Hybrid Capture 2 (HC2; Qiagen, Germany) method. In the second part of the study, consensus real-time polymerase chain reaction (RT-PCR) (Takara Bio Inc., Japan) was performed in 152 samples which included HC2 positive and randomly selected negative samples, and then the HPV genotypes were detected by using a commercial kit based on pyrosequencing method (Diatech Pharmacogenetics S.R.L, Italy). In the first part of the study, HC2 test was found positive in 3% (32/1081) of the women, while in 4.4% (47/1081) Pap smear was positive alone or with HC2 test. Five (0.5%) samples yielded positive results with both of the methods, and four of them were positive for high risk HPV types. Cytology results were negative in 19 out of 23 (23/1081, 2.1%) samples that were reported as high risk HPV by HC2 test. On the other hand, 42 (42/1081, 3.9%) samples that were positive by cytology yielded negative results by HC2 test. In the second part of the study, 32 (21.1%) of 152 selected

  5. Dissociation of internal energy-selected methyl bromide ion revealed from threshold photoelectron-photoion coincidence velocity imaging

    International Nuclear Information System (INIS)

    Dissociative photoionization of methyl bromide (CH3Br) in an excitation energy range of 10.45–16.90 eV has been investigated by using threshold photoelectron-photoion coincidence (TPEPICO) velocity imaging. The coincident time-of-flight mass spectra indicate that the ground state X2E of CH3Br+ is stable, and both A2A1 and B2E ionic excited states are fully dissociative to produce the unique fragment ion of CH3+. From TPEPICO 3D time-sliced velocity images of CH3+ dissociated from specific state-selected CH3Br+ ion, kinetic energy release distribution (KERD) and angular distribution of CH3+ fragment ion are directly obtained. Both spin-orbit states of Br(2P) atom can be clearly observed in fast dissociation of CH3Br+(A2A1) ion along C–Br rupture, while a KERD of Maxwell-Boltzmann profile is obtained in dissociation of CH3Br+(B2E) ion. With the aid of the re-calculated potential energy curves of CH3Br+ including spin-orbit coupling, dissociation mechanisms of CH3Br+ ion in A2A1 and B2E states along C–Br rupture are revealed. For CH3Br+(A2A1) ion, the CH3+ + Br(2P1/2) channel is occurred via an adiabatic dissociation by vibration, while the Br(2P3/2) formation is through vibronic coupling to the high vibrational level of X2E state followed by rapid dissociation. C–Br bond breaking of CH3Br+(B2E) ion can occur via slow internal conversion to the excited vibrational level of the lower electronic states and then dissociation

  6. Basin scale assessment of gas hydrate dissociation in response to climate change

    Energy Technology Data Exchange (ETDEWEB)

    Reagan, M.; Moridis, G.; Elliott, S.; Maltrud, M.; Cameron-Smith, P.

    2011-07-01

    Paleooceanographic evidence has been used to postulate that methane from oceanic hydrates may have had a significant role in regulating climate. However, the behavior of contemporary oceanic methane hydrate deposits subjected to rapid temperature changes, like those now occurring in the arctic and those predicted under future climate change scenarios, has only recently been investigated. Field investigations have discovered substantial methane gas plumes exiting the seafloor along the Arctic Ocean margin, and the plumes appear at depths corresponding to the upper limit of a receding gas hydrate stability zone. It has been suggested that these plumes may be the first visible signs of the dissociation of shallow hydrate deposits due to ongoing climate change in the arctic. We simulate the release of methane from oceanic deposits, including the effects of fully-coupled heat transfer, fluid flow, hydrate dissociation, and other thermodynamic processes, for systems representative of segments of the Arctic Ocean margins. The modeling encompasses a range of shallow hydrate deposits from the landward limit of the hydrate stability zone down to water depths beyond the expected range of century-scale temperature changes. We impose temperature changes corresponding to predicted rates of climate change-related ocean warming and examine the possibility of hydrate dissociation and the release of methane. The assessment is performed at local-, regional-, and basin-scales. The simulation results are consistent with the hypothesis that dissociating shallow hydrates alone can result in significant methane fluxes at the seafloor. However, the methane release is likely to be confined to a narrow region of high dissociation susceptibility, defined by depth and temperature, and that any release will be continuous and controlled, rather than explosive. This modeling also establishes the first realistic bounds for methane release along the arctic continental shelf for potential hydrate

  7. Synovectomy by Neutron capture

    International Nuclear Information System (INIS)

    The Synovectomy by Neutron capture has as purpose the treatment of the rheumatoid arthritis, illness which at present does not have a definitive curing. This therapy requires a neutron source for irradiating the articulation affected. The energy spectra and the intensity of these neutrons are fundamental since these neutrons induce nuclear reactions of capture with Boron-10 inside the articulation and the freely energy of these reactions is transferred at the productive tissue of synovial liquid, annihilating it. In this work it is presented the neutron spectra results obtained with moderator packings of spherical geometry which contains in its center a Pu239 Be source. The calculations were realized through Monte Carlo method. The moderators assayed were light water, heavy water base and the both combination of them. The spectra obtained, the average energy, the neutron total number by neutron emitted by source, the thermal neutron percentage and the dose equivalent allow us to suggest that the moderator packing more adequate is what has a light water thickness 0.5 cm (radius 2 cm) and 24.5 cm heavy water (radius 26.5 cm). (Author)

  8. Data on ionization, excitation, dissociation and dissociative ionization of targets by helium ion bombardments, (1)

    International Nuclear Information System (INIS)

    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)

  9. Workshop on neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Fairchild, R.G.; Bond, V.P. (eds.)

    1986-01-01

    Potentially optimal conditions for Neutron Capture Therapy (NCT) may soon be in hand due to the anticipated development of band-pass filtered beams relatively free of fast neutron contaminations, and of broadly applicable biomolecules for boron transport such as porphyrins and monoclonal antibodies. Consequently, a number of groups in the US are now devoting their efforts to exploring NCT for clinical application. The purpose of this Workshop was to bring these groups together to exchange views on significant problems of mutual interest, and to assure a unified and effective approach to the solutions. Several areas of preclinical investigation were deemed to be necessary before it would be possible to initiate clinical studies. As neither the monomer nor the dimer of sulfhydryl boron hydride is unequivocally preferable at this time, studies on both compounds should be continued until one is proven superior.

  10. Workshop on neutron capture therapy

    International Nuclear Information System (INIS)

    Potentially optimal conditions for Neutron Capture Therapy (NCT) may soon be in hand due to the anticipated development of band-pass filtered beams relatively free of fast neutron contaminations, and of broadly applicable biomolecules for boron transport such as porphyrins and monoclonal antibodies. Consequently, a number of groups in the US are now devoting their efforts to exploring NCT for clinical application. The purpose of this Workshop was to bring these groups together to exchange views on significant problems of mutual interest, and to assure a unified and effective approach to the solutions. Several areas of preclinical investigation were deemed to be necessary before it would be possible to initiate clinical studies. As neither the monomer nor the dimer of sulfhydryl boron hydride is unequivocally preferable at this time, studies on both compounds should be continued until one is proven superior

  11. Historic Methods for Capturing Magnetic Field Images

    Science.gov (United States)

    Kwan, Alistair

    2016-01-01

    I investigated two late 19th-century methods for capturing magnetic field images from iron filings for historical insight into the pedagogy of hands-on physics education methods, and to flesh out teaching and learning practicalities tacit in the historical record. Both methods offer opportunities for close sensory engagement in data-collection…

  12. Historic Methods for Capturing Magnetic Field Images

    Science.gov (United States)

    Kwan, Alistair

    2016-03-01

    I investigated two late 19th-century methods for capturing magnetic field images from iron filings for historical insight into the pedagogy of hands-on physics education methods, and to flesh out teaching and learning practicalities tacit in the historical record. Both methods offer opportunities for close sensory engagement in data-collection processes.

  13. Oxygen adsorption and dissociation during the oxidation of monolayer Ti2C

    KAUST Repository

    Gan, Li-Yong

    2013-08-20

    Exfoliated two-dimensional early transition metal carbides and carbonitrides are usually not terminated by metal atoms but saturated by O, OH, and/or F, thus making it difficult to understand the surface structure evolution and the induced electronic modifications. To fill this gap, density functional theory and molecular dynamics simulations are performed to capture the initial stage of the oxidation process of Ti2C, a prototypical example from the recently fabricated class of two-dimensional carbides and carbonitrides. It is shown that the unsaturated Ti 3d orbitals of the pristine Ti2C surface interact strongly with the approaching O2 molecules, resulting in barrierless O2 dissociation. The diffusion of the dissociated O atoms is also found to be very facile. Molecular dynamics simulations suggest that both dissociation and diffusion are enhanced as the O2 coverage increases to 0.25 monolayer. For a coverage of less than 0.11 monolayer, the adsorbates lead to a minor modification of the electronic properties of Ti2C, while the modification is remarkable at 0.25 monolayer. The formed Ti2CO2 after O saturation is an indirect narrow gap semiconductor (0.33 eV) with high intrinsic carrier concentration at room temperature and high thermodynamic stability at intermediate temperature (e.g., 550 °C).

  14. Duality and factorisation in diffractive dissociations

    International Nuclear Information System (INIS)

    A trial analysis of the mechanism that creates diffractive systems is presented. The t-channel point of view is adopted, namely the description of the diffractive processes by exchange of the Pomeron in the crossed channel the duality concept playing a prime role in the work as a whole. A dualised three-component Deck model (MD3CD) is suggested for describing the nucleon dissociation process in the Nπ system. The fundamental ingredient in the building of this model springs from the contributory addition to the Deck model of the direct term, in other words of the elastic scattering of the initial state on the target followed by its dissociation (a → a*π). This mechanism produces a line of zeros in the space of the three variables: mass, momentum transfer and Cos Theta. The mass-slope-Cos Theta correlation observed experimentally is only the outcome of the existence of mobile zeros. The comparison with the experiment is satisfactory. Further, the addition of the third component improves still more the distribution in the other variables. During the generalisation of the model (MD3CD) there is a discussion on the systematics of the mass-slope correlation and the prescriptions of Born's term. A generalisation to the diffractive double dissociation pπ-pπ- of the three-component Deck model is suggested and a critical study is made of the factorisation of the Pomeron. By allowing for the secondary contributions suggested by the duality diagrams, it is shown how it is possible to obtain interference effects between the dominant contribution of the double Pomeron-π exchange and that of the double B-meson (the π degeneracy partner) and ω exchange. The importance of the Reggeon-Reggeon-Particle vertex phase of this latter contribution is shown. The cross-over is obtained correctly when the Deck graph of the π exchange is adjusted by the contribution of the secondary trajectories, in good agreement with the experiment

  15. Capturing the Daylight Dividend

    Energy Technology Data Exchange (ETDEWEB)

    Peter Boyce; Claudia Hunter; Owen Howlett

    2006-04-30

    Capturing the Daylight Dividend conducted activities to build market demand for daylight as a means of improving indoor environmental quality, overcoming technological barriers to effective daylighting, and informing and assisting state and regional market transformation and resource acquisition program implementation efforts. The program clarified the benefits of daylight by examining whole building systems energy interactions between windows, lighting, heating, and air conditioning in daylit buildings, and daylighting's effect on the human circadian system and productivity. The project undertook work to advance photosensors, dimming systems, and ballasts, and provided technical training in specifying and operating daylighting controls in buildings. Future daylighting work is recommended in metric development, technology development, testing, training, education, and outreach.

  16. Robust automated knowledge capture.

    Energy Technology Data Exchange (ETDEWEB)

    Stevens-Adams, Susan Marie; Abbott, Robert G.; Forsythe, James Chris; Trumbo, Michael Christopher Stefan; Haass, Michael Joseph; Hendrickson, Stacey M. Langfitt

    2011-10-01

    This report summarizes research conducted through the Sandia National Laboratories Robust Automated Knowledge Capture Laboratory Directed Research and Development project. The objective of this project was to advance scientific understanding of the influence of individual cognitive attributes on decision making. The project has developed a quantitative model known as RumRunner that has proven effective in predicting the propensity of an individual to shift strategies on the basis of task and experience related parameters. Three separate studies are described which have validated the basic RumRunner model. This work provides a basis for better understanding human decision making in high consequent national security applications, and in particular, the individual characteristics that underlie adaptive thinking.

  17. Particle capture device

    Energy Technology Data Exchange (ETDEWEB)

    Jayne, John T.; Worsnop, Douglas R.

    2016-02-23

    In example embodiments, particle collection efficiency in aerosol analyzers and other particle measuring instruments is improved by a particle capture device that employs multiple collisions to decrease momentum of particles until the particles are collected (e.g., vaporized or come to rest). The particle collection device includes an aperture through which a focused particle beam enters. A collection enclosure is coupled to the aperture and has one or more internal surfaces against which particles of the focused beam collide. One or more features are employed in the collection enclosure to promote particles to collide multiple times within the enclosure, and thereby be vaporized or come to rest, rather than escape through the aperture.

  18. 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.

  19. Occipitocervical dissociation-incidence, evaluation, and treatment.

    Science.gov (United States)

    Kasliwal, Manish K; Fontes, Ricardo B; Traynelis, Vincent C

    2016-09-01

    Traumatic occipitocervical dissociation (OCD) results from ligamentous injury to the craniocervical junction and is associated with a high rate of mortality and significant neurologic morbidity. The diagnosis is frequently missed on initial lateral cervical spinal radiographs mainly due to inadequate visualization of radiological landmarks and low degree of suspicion. Widespread availability of multidetector computed tomography (MDCT) of the spine and development of better diagnostic radiological criteria has allowed timely diagnosis and good clinical outcome following posterior occipitocervical fusion and instrumentation for a pathology that was once considered uniformly fatal. The present paper reviews the clinical features, diagnosis, and management of OCD in light of most recent literature. PMID:27255101

  20. Semiclathrate-based CO2 capture from flue gas mixtures: An experimental approach with thermodynamic and Raman spectroscopic analyses

    International Nuclear Information System (INIS)

    Highlights: • Semiclathrates were used for post-combustion CO2 capture. • The highest gas uptake was observed for the TBAC (3.3 mol%) semiclathrate. • CO2 was enriched to approximately 60% in the semiclathrate phase. • Gas enclathration in the semiclathrate lattices was confirmed with Raman spectroscopy. - Abstract: Semiclathrate-based CO2 capture from flue gas in the presence of various quaternary ammonium salts (QASs) such as tetra-n-butyl ammonium bromide (TBAB), tetra-n-butyl ammonium chloride (TBAC), and tetra-n-butyl ammonium fluoride (TBAF) was investigated with a primary focus on the thermodynamic, kinetic, and spectroscopic aspects. The thermodynamic stability of the CO2 (20%) + N2 (80%) + QAS semiclathrates was examined with an isochoric method using a high pressure reactor as well as with dissociation enthalpy measurement using a high pressure micro-differential scanning calorimeter (HP μ-DSC). The TBAF semiclathrate with CO2 (20%) + N2 (80%) showed the most significant equilibrium pressure reduction at a specified temperature. However, the TBAC semiclathrate had the highest gas uptake and steepest CO2 concentration change in the vapor phase, which indicates the largest gas storage capacity for CO2 capture. CO2 was observed to be preferentially captured and enriched to approximately 60% in the semiclathrate phase. The CO2 selectivity was independent of the type of QASs used. The Raman spectroscopic results revealed that both CO2 and N2 are enclathrated in the small cages of the QAS semiclathrates and that the enclathration of guest gas molecules does not change the structure of the semiclathrates

  1. Strain-Induced Water Dissociation on Supported Ultrathin Oxide Films

    CERN Document Server

    Song, Zhenjun; Xu, Hu

    2015-01-01

    Controlling the dissociation of single water molecule on an insulating surface plays a crucial role in many catalytic reactions. In this Letter, we have identified the enhanced chemical reactivity of ultrathin MgO(100) films deposited on Mo(100) substrate that causes water dissociation. We reveal that the ability to split water on insulating surface closely depends on the lattice mismatch between ultrathin films and the underlying substrate, and substrate-induced in-plane tensile strain dramatically results in water dissociation on MgO(100). Three dissociative adsorption configurations of water with lower energy are predicted, and the structural transition going from molecular form to dissociative form is almost barrierless. Our results provide an effective avenue to achieve water dissociation at the single-molecule level and shed light on how to tune the chemical reactions of insulating surfaces by choosing the suitable substrates.

  2. Being in rhythm: dissociative attunement in therapeutic process.

    Science.gov (United States)

    Hopenwasser, Karen

    2008-01-01

    Dissociative attunement is a profound rhythmic encounter in therapeutic treatment. Attunement is a synchronized awareness of implicit knowing that is nonlinear and bidirectional. Empathically attuned clinicians are like microtonal tuning forks. They resonate with a variety of emotional pitches and will resonate with nuanced shifting of emotional tone. This resonance is the basis of dissociative attunement. Concepts such as empathic attunement, affect attunement, "the unthought known," "implicit relational knowing," and "a two-person unconscious" help us to understand unique aspects of projective identification, transference, and countertransference within the dissociative frame. However, "dissociative" attunements are systemically self-emergent moments in which multiple self-states are shared by means other than projection. Using clinical vignettes, I demonstrate how dissociative attunement can paradoxically appear to be misattunement. By synthesizing scientific and theoretical concepts applied to these clinical moments, we can understand dissociative attunement as a therapeutic tool as well as a pathway to vicarious traumatization. PMID:19042783

  3. Strain-induced water dissociation on supported ultrathin oxide films.

    Science.gov (United States)

    Song, Zhenjun; Fan, Jing; Xu, Hu

    2016-01-01

    Controlling the dissociation of single water molecule on an insulating surface plays a crucial role in many catalytic reactions. In this work, we have identified the enhanced chemical reactivity of ultrathin MgO(100) films deposited on Mo(100) substrate that causes water dissociation. We reveal that the ability to split water on insulating surface closely depends on the lattice mismatch between ultrathin films and the underlying substrate, and substrate-induced in-plane tensile strain dramatically results in water dissociation on MgO(100). Three dissociative adsorption configurations of water with lower energy are predicted, and the structural transition going from molecular form to dissociative form is almost barrierless. Our results provide an effective avenue to achieve water dissociation at the single-molecule level and shed light on how to tune the chemical reactions of insulating surfaces by choosing the suitable substrates. PMID:26953105

  4. Dissociation in individuals denying trauma exposure: findings from two samples.

    Science.gov (United States)

    Briere, John; Runtz, Marsha

    2015-06-01

    A number of studies suggest that dissociation is reliably related to trauma exposure, and that inadequate regulation of posttraumatic distress may be a significant factor. We examined whether affect dysregulation predicts dissociation in those denying any lifetime exposure to trauma. These relationships were evaluated in a general population sample and a second sample of nontraumatized university students. In the first study, multivariate analyses indicated that, along with gender, affect dysregulation was a relatively strong predictor, accounting for 27% of the variance in dissociation. In the replication study, dissociation was associated with affect dysregulation, but not gender. Affect dysregulation seems to predict dissociative symptomatology in nontraumatized individuals. It is hypothesized that emotional distress, whether from trauma or other etiologies, motivates dissociation to the extent that it challenges the individual's compromised capacity for affect regulation. Treatment implications may include the potential helpfulness of interventions that increase emotion regulation skills. PMID:25974057

  5. Dissociative Adsorption of Molecules on Graphene and Silicene

    CERN Document Server

    Gurel, H Hakan; Ciraci, S

    2014-01-01

    We study the interaction of H$_2$, O$_2$, CO, H$_2$O and OH molecules with the vacancy defects of graphene and silicene. Atoms around the bare vacancy reconstruct and specific chemically active sites are created. While H$_2$, O$_2$ and CO remain intact on both pristine graphene and silicene, these molecules can dissociate when they are placed at the close proximity of these chemically active sites and nucleate centers for the hydrogenation and oxygenation. Saturation of the dangling bonds at the defect sites by constituent atoms of dissociated molecules gives rise to significant modification of electronic and magnetic properties. We analyzed the mechanism of the dissociation and revealed a concerted action of surrounding host atoms together with dissociated molecules to lower the energy barrier needed for dissociation. The dissociations of H$_2$O and OH are hindered by high energy barriers. Our study suggests that graphene and silicene can be functionalized by creating meshes of single vacancy, where specific...

  6. Mass and orientation effects in dissociative collisions between rare gas atoms and alkali halide molecules

    International Nuclear Information System (INIS)

    The collision induced dissociation of alkali halide molecules to ion pairs upon impact with hyperthermal rare gas atoms has been investigated using the crossed molecular beam method. Relative total cross sections for the dissociation of CsI, CsBr, RbI, and KI to ion pairs upon collision with xenon and krypton have been measured over a relative collision energy range from threshold to 10 and 8 eV, respectively. In addition, complete angular and energy distributions of both dissociated ions from Xe+CsI, CsBr, and RbI collisions and from Kr+CsI and CsBr collisions have been obtained at several collision energies within the above energy range. Mass, collision orientation, and energy dependence effects observed throughout this work define two limiting case dissociation mechanisms for the Xe(Kr)+MX→Xe(Kr)+M++X- processes. The dominant dissociation configuration consists of the rare gas atom incident on the light atom end of the alkali halide molecule in a near collinear collision. The less preferred dissociation mechanism results when the rare gas atom is incident in a near collinear configuration on the heavy atom end of the alkali halide molecule. Experimental measurements of the percentage of energy transfer from the relative kinetic energy between Xe(Kr) and MX to the relative motion of M+--X- range as high as 95%; these percentage energy transfers correlate well with the predictions of an impulsive collision model. Three-dimensional classical trajectory calculations using realistic interaction potentials have been performed and they verify the dynamical interpretation suggested by the experiments

  7. The Electron Capture $^{163}$Ho Experiment ECHo

    CERN Document Server

    Blaum, K; Duellmann, C E; Eberhardt, K; Eliseev, S; Enss, C; Faessler, A; Fleischmann, A; Gastaldo, L; Kempf, S; Krivoruchenko, M; Lahiri, S; Maiti, M; Novikov, Yu N; Ranitzsch, P C -O; Simkovic, F; Szusc, Z; Wegner, M

    2013-01-01

    The determination of the absolute scale of the neutrino masses is one of the most challenging questions in particle physics. Different approaches are followed to achieve a sensitivity on neutrino masses in the sub-eV range. Among them, experiments exploring the beta decay and electron capture processes of suitable nuclides can provide necessary information on the electron neutrino mass value. In this talk we present the Electron Capture 163-Ho experiment ECHo, which aims to investigate the electron neutrino mass in the sub-eV range by means of the analysis of the calorimetrically measured energy spectrum following the electron capture process of 163-Ho. A high precision and high statistics spectrum will be measured by means of low temperature magnetic calorimeter arrays. We present preliminary results obtained with a first prototype of single channel detectors as well as the participating groups and their on-going developments.

  8. Chemical composition of asphaltenes from thermal dissociation of brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Evstaf' ev, S.N.; Denisova, T.I.; Tuturina, V.V.

    1987-07-01

    Investigates chemical composition of asphaltenes and preasphaltenes separated from liquid products of thermal dissociation of Azeisk deposit brown coal in tetralin. Asphaltenes and preasphaltenes represent a mixture of mainly aromatic compounds containing bi- and tri-cyclic aromatic fractions differing by length of aliphatic substituents and by distribution of oxygen-containing functional groups. Describes tests carried out at 300-420 C in autoclaves using 0.1-0.3 mm coal particles and tetralin containing decalin (2.8%) and naphthalene (5.2%). Establishes that asphaltenes soluble in acetone are represented by low-molecular saturated compounds; about 60% of oxygen in asphaltenes and preasphaltenes is attached to ethereal and heterocyclic structure groups. 10 refs.

  9. Focusing on dissociated motor development in Brazilian children

    Directory of Open Access Journals (Sweden)

    Minami Maria Avanise Yumi

    2001-01-01

    Full Text Available Dissociated motor development (DMD is considered when the baby starts independent walking late, with normality of the other fields of development. There is evidence that babies with DMD present an atypical crawling pattern and hypotonia. To investigate the frequency and characteristics of DMD, neurological examination was performed monthly in 177 healthy full-term babies from 6 months age, in urban and rural zone samples in Brazil. Among 20 children with atypical crawling, none presented hypotonia neither did they start independent walking late. The means of the ages at the begining of atypical crawling and independent walking acquisitions, 7.40mo (SD 1.4 and 12.76mo (SD 2.5 respectively, did not differ from the group with crossed crawling pattern. Thus, in this sample of Brazilian healthy children we did not find cases with DMD.

  10. Dissociative recombination in reactive flows related to planetary atmospheric entries

    Directory of Open Access Journals (Sweden)

    Bultel Arnaud

    2015-01-01

    Full Text Available The Dissociative Recombination (DR processes play a significant role in plasma chemistry. This article illustrates this role from the modeling point of view in the case of reactive flows related to atmospheric entry plasmas. Two situations are investigated, for which the studied plasma is nitrogen. The first configuration corresponds to the relaxation process behind a strong shock wave moving at high Mach number in a shock tube, the second one to the recombination taking place in an expanding plasma flowing in a diverging nozzle. In both cases, the collisional-radiative model CoRaM-N2, involving N2, N, N2+, N+ and electrons, is implemented in an Eulerian 1D code able to compute the aerodynamic fields; calculations are performed in standard conditions. We show that, according to the rate coefficients used for the DR processes, the population density of the charged species especially N2+ is strongly modified only for the post-shock flow.

  11. Imaging the molecular dynamics of dissociative electron attachment to water

    Energy Technology Data Exchange (ETDEWEB)

    Adaniya, Hidihito; Rudek, B.; Osipov, Timur; Haxton, Dan; Weber, Thorsten; Rescigno, Thomas N.; McCurdy, C.W.; Belkacem, Ali

    2009-10-19

    Momentum imaging experiments on dissociative electron attachment to the water molecule are combined with ab initio theoretical calculations of the angular dependence of the quantum mechanical amplitude for electron attachment to provide a detailed picture of the molecular dynamics of dissociation attachment via the two lowest energy Feshbach resonances. The combination of momentum imaging experiments and theory can reveal dissociation dynamics for which the axial recoil approximation breaks down and thus provides a powerful reaction microscope for DEA to polyatomics.

  12. The Role of Dissociation in the Cycle of Violence

    OpenAIRE

    Daisy, Nicole V.; Hien, Denise A.

    2014-01-01

    The primary aim of this study was to examine the role of dissociation in the relationship between child maltreatment and intimate partner violence among 148 inner city women. It was proposed that dissociation would be a mediator in the relationship between child maltreatment and intimate partner perpetration. Overall, the hypothesis was supported. Findings revealed that women with a history of child maltreatment who experienced high levels of dissociation were more likely to be perpetrators o...

  13. 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....

  14. High resolution parallel reaction monitoring with electron transfer dissociation for middle-down proteomics.

    Science.gov (United States)

    Sweredoski, Michael J; Moradian, Annie; Raedle, Matthias; Franco, Catarina; Hess, Sonja

    2015-08-18

    In recent years, middle-down proteomics has emerged as a popular technique for the characterization and quantification of proteins not readily amenable to typical bottom-up approaches. So far, all high resolution middle-down approaches are done in data-dependent acquisition mode, using both collision-induced dissociation or electron capture/transfer dissociation techniques. Here, we explore middle-down proteomics with electron transfer dissociation using a targeted acquisition mode, parallel reaction monitoring (PRM), on an Orbitrap Fusion. As an example of a highly modified protein, we used histone H3 fractions from untreated and DMSO-treated Murine ErythroLeukemia (MEL) cells. We first determined optimized instrument parameters to obtain high sequence coverage using a synthetic standard peptide. We then setup a combined method of both MS1 scans and PRM scans of the 20 most abundant combinations of methylation and acetylation of the +10 charge state of the N-terminal tail of H3. Weak cation exchange hydrophilic interaction chromatography was used to separate the N-terminal H3 tail, primarily, by its acetylation and, to a secondary degree, by its methylation status, which aided in the interpretation of the results. After deconvolution of the highly charged ions, peaks were annotated to a minimum set of 254 H3 proteoforms in the untreated and treated samples. Upon DMSO treatment, global quantitation changes from the MS1 level show a relative decrease of 2, 3, 4, and 5 acetylations and an increase of 0 and 1 acetylations. A fragment ion map was developed to visualize specific differences between treated and untreated samples. Taken together, the data presented here show that middle-down proteomics with electron transfer dissociation using PRM is a novel, attractive method for the effective analysis and quantification of large and highly modified peptides. PMID:26176279

  15. Characterization of oligodeoxynucleotides by electron detachment dissociation fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Yang, Jiong; Mo, Jingjie; Adamson, Julie T; Håkansson, Kristina

    2005-03-15

    Electron detachment dissociation (EDD), recently introduced by Zubarev and co-workers for the dissociation of multiply charged biomolecular anions via a radical ion intermediate, has been shown to be analogous to electron capture dissociation (ECD) in several respects, including more random peptide fragmentation and retention of labile posttranslational modifications. We have previously demonstrated unique fragmentation behavior in ECD compared to vibrational excitation for oligodeoxynucleotide cations. However, that approach is limited by the poor sensitivity for oligonucleotide ionization in positive ion mode. Here, we show implementation of EDD on a commercial Fourier transform ion cyclotron resonance mass spectrometer utilizing two different configurations: a heated filament electron source and an indirectly heated hollow dispenser cathode electron source. The dispenser cathode configuration provides higher EDD efficiency and additional fragmentation channels for hexamer oligodeoxynucleotides. As in ECD, even-electron d/w ion series dominate the spectra, but we also detect numerous a/z (both even-electron and radical species), (a/z - B), c/x, (c/x - B), and (d/w - B) ions with minimal nucleobase loss from the precursor ions. In contrast to previous high-energy collision-activated dissociation (CAD) and ion trap CAD of radical oligonucleotide anions, we only observe minimum sugar cross-ring cleavage, possibly due to the short time scale of EDD, which limits secondary fragmentation. Thus, EDD provides fragmentation similar to ECD for oligodeoxynucleotides but at enhanced sensitivity. Finally, we show that noncovalent bonding in a DNA duplex can be preserved following EDD, illustrating another analogy with ECD. We believe the latter finding implies EDD has promise for characterization of nucleic acid structure and folding. PMID:15762599

  16. Dissociation of silica at high pressure

    Science.gov (United States)

    Hicks, Damien; Boehly, Tom

    2005-07-01

    Measurements of the temperature and optical reflectivity of quartz and fused silica under shock loading from 100 to 1000 GPa have revealed evidence for dissociation of silica between ˜150 and 400 GPa. Using attenuating laser-driven shock waves a continuous record of the temperature and reflectivity dependence on pressure has been obtained in both materials allowing the specific heat capacity and electronic conductivity to be deduced. Results show that between 150 and 400 GPa the specific heat rises significantly above that expected from the Dulong-Petit law, indicating the presence of a latent energy. Coincident with this anomalous specific heat is a rapid rise in electronic conductivity. Both these observables suggest that dissociation is occurring in the dense fluid. In addition temperature measurements near 5000 K detect a discontinuity at the melt transition, as measured earlier on gas gun experiments. This work was performed under the auspices of the US DOE by LLNL under Contract No. W-7405-ENG-48 and by the University of Rochester under Cooperative Agreement No. DE-FC03-92SF19460.

  17. Multigenerational Dissociation: A Framework for Building Narrative.

    Science.gov (United States)

    McCollum, Sally E

    2015-01-01

    This paper presents the concept of Multigenerational Dissociation (MGD), a behavior pattern that occurs in families in which violence and abuse are re-enacted from one generation to the next, accompanied by denial that the trauma occurred, or if it did, that it was destructive. While revictimization, reenactment, and the intergenerational transmission of trauma are discussed extensively in the literature, MGD helps to view them within a broad historical framework. This is useful for conceptualizing cases therapeutically, and it can also contribute to research on dissociation and recovered memories of trauma and abuse by demonstrating the value of narrative clinical data. Case material is used to illustrate how MGD occurs in people's lives and affects their memories, demonstrating how it becomes a frame within which to convey the dynamics of how traumatic experiences are remembered. This also demonstrates that when clinicians contribute their own narrative data to research on traumatic memory, the science is more accurate, relevant, and comprehensible to clinical and nonclinical researchers. PMID:26158318

  18. 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. PMID:20830631

  19. 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.

  20. Dissociative and non-dissociative photoionization of molecular fluorine from inner and valence shells

    Energy Technology Data Exchange (ETDEWEB)

    Ayuso, D.; Palacios, A. [Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Decleva, P. [Dipartimento di Scienze Chimiche e Farmaceutiche, Università di Trieste, 34127 Trieste (Italy); CNR-IOM, Trieste (Italy); Martín, F., E-mail: fernando.martin@uam.es [Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Instituto Madrileño de Estudios Avanzados en Nanociencia, Cantoblanco, 28049 Madrid (Spain)

    2014-08-15

    Highlights: • We theoretically analyze the angle-integrated photoionization cross sections of the fluorine molecule, which have been computed up to hundreds of eV using a DFT-like methodology that takes into account the nuclear degrees of freedom. • We have considered electron ejection from all the molecular orbitals and found that the corresponding cross sections show an oscillatory behavior as a function of the photoelectron momentum, which is the result of the double-slit type interferences. • We further compute dissociative and non-dissociative ionization channels. • Dissociative ionization is negligible in other diatomic molecules such N{sub 2} or CO, whereas is visible for F{sub 2} when the electron is ejected from the 1u or the 3σ{sub g} molecular orbitals. - Abstract: We present a theoretical study of F{sub 2} photoionization in the range 0–40 a.u. of photoelectron energy, where the undulatory behavior of the corresponding angle-integrated cross sections due to electron emission from equivalent centers is apparent. These double-slit type interferences are observed in both inner- and valence-shell ionization. We analyze confinement effects that appear at given energies when the electron is ejected parallel to the molecular axis. Since we account for the nuclear degrees of freedom, we evaluate and discuss the vibrationally resolved cross sections, including both dissociative and non-dissociative ionization channels. We also analyze the ratios between the latter cross sections and the relationship between the observed oscillations and the structure of the molecule.

  1. Accurate studies on dissociation energies of diatomic molecules

    Institute of Scientific and Technical Information of China (English)

    SUN; WeiGuo; FAN; QunChao

    2007-01-01

    The molecular dissociation energies of some electronic states of hydride and N2 molecules were studied using a parameter-free analytical formula suggested in this study and the algebraic method (AM) proposed recently. The results show that the accurate AM dissociation energies DeAM agree excellently with experimental dissociation energies Deexpt, and that the dissociation energy of an electronic state such as the 23△g state of 7Li2 whose experimental value is not available can be predicted using the new formula.

  2. 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

  3. Lunar Sulfur Capture System

    Science.gov (United States)

    Berggren, Mark; Zubrin, Robert; Bostwick-White, Emily

    2013-01-01

    The Lunar Sulfur Capture System (LSCS) protects in situ resource utilization (ISRU) hardware from corrosion, and reduces contaminant levels in water condensed for electrolysis. The LSCS uses a lunar soil sorbent to trap over 98 percent of sulfur gases and about two-thirds of halide gases evolved during hydrogen reduction of lunar soils. LSCS soil sorbent is based on lunar minerals containing iron and calcium compounds that trap sulfur and halide gas contaminants in a fixed-bed reactor held at temperatures between 250 and 400 C, allowing moisture produced during reduction to pass through in vapor phase. Small amounts of Earth-based polishing sorbents consisting of zinc oxide and sodium aluminate are used to reduce contaminant concentrations to one ppm or less. The preferred LSCS configuration employs lunar soil beneficiation to boost concentrations of reactive sorbent minerals. Lunar soils contain sulfur in concentrations of about 0.1 percent, and halogen compounds including chlorine and fluorine in concentrations of about 0.01 percent. These contaminants are released as gases such as H2S, COS, CS2,HCl, and HF during thermal ISRU processing with hydrogen or other reducing gases. Removal of contaminant gases is required during ISRU processing to prevent hardware corrosion, electrolyzer damage, and catalyst poisoning. The use of Earth-supplied, single-use consumables to entirely remove contaminants at the levels existing in lunar soils would make many ISRU processes unattractive due to the large mass of consumables relative to the mass of oxygen produced. The LSCS concept of using a primary sorbent prepared from lunar soil was identified as a method by which the majority of contaminants could be removed from process gas streams, thereby substantially reducing the required mass of Earth-supplied consumables. The LSCS takes advantage of minerals containing iron and calcium compounds that are present in lunar soil to trap sulfur and halide gases in a fixedbed reactor

  4. Hydrogen Dissociation and Diffusion on Ni and Ti -doped Mg(0001) Surfaces

    OpenAIRE

    Pozzo, M.; Alfè, D.; Amieiro, A.; French, S; Pratt, A.

    2008-01-01

    It is well known, both theoretically and experimentally, that alloying MgH$_2$ with transition elements can significantly improve the thermodynamic and kinetic properties for H$_2$ desorption, as well as the H$_2$ intake by Mg bulk. Here we present a density functional theory investigation of hydrogen dissociation and surface diffusion over Ni-doped surface, and compare the findings to previously investigated Ti-doped Mg(0001) and pure Mg(0001) surfaces. Our results show that the energy barri...

  5. 胺法脱碳系统动态特性及控制策略研究%Investigation of the Dynamic Behavior and Control Strategies for a CO2 Capture System Using Amine Solution

    Institute of Scientific and Technical Information of China (English)

    李小飞; 王淑娟; 陈昌和

    2014-01-01

    The amine-based CO2 capture system is an inherently dynamic system that is affected by the load variations in the up-stream power plant due to fluctuations in electricity demand. However, most of researches in this field are based on the steady state operation model, little dynamic data and analysis of the dynamic behavior of a CO2 capture system are available in open literatures. A dynamic model of amine-based CO2 capture system was developed with Aspen Dynamics software based on a typical coal fired power plant. Dynamic responses of the amine-based CO2 capture system with basic control structure were studied when step change in reboiler heat duty, flue gas flowrate and CO2 composition. The results show that the CO2 removal efficiency is influenced by the flue gas disturbances. The CO2 removal target is guaranteed by two proportional control strategies, and operating parameters can be adjusted according to the changes of the flowrate and CO2 composition in flue gas. Dynamic simulations show that the CO2 capture system can achieve removal targets with the proposed control strategies.%由于电力需求的波动,受上游碳捕集电厂负荷变化的影响,胺法脱碳系统本质上是一个动态系统。但绝大多数关于胺法脱碳系统的研究是基于稳态运行方式展开的,对碳捕集系统动态研究还处于起步阶段。文中基于一个典型的燃煤电厂胺法脱碳装置,应用Aspen Dynamics软件建立胺法脱碳系统动态模型。研究了带基本控制结构胺法脱碳系统在再沸器热功率、烟气流量及烟气组分阶跃变化时,吸收和再生过程的动态响应特性。结果表明,在阶跃扰动下,CO2脱除率发生阶跃变化。为了实现固定的 CO2脱除率,提出2种比例控制策略,根据烟气处理量及组分浓度变化,分别通过调节贫液流量及贫液CO2担载量来保持固定的CO2脱除率。动态分析表明,在烟气流量及组分阶跃变化时,2

  6. Resource capture by single leaves

    Energy Technology Data Exchange (ETDEWEB)

    Long, S.P.

    1992-05-01

    Leaves show a variety of strategies for maximizing CO{sub 2} and light capture. These are more meaningfully explained if they are considered in the context of maximizing capture relative to the utilization of water, nutrients and carbohydrates reserves. There is considerable variation between crops in their efficiency of CO{sub 2} and light capture at the leaf level. Understanding of these mechanisms indicate some ways in which efficiency of resource capture could be level cannot be meaningfully considered without simultaneous understanding of implications at the canopy level. 36 refs., 5 figs., 1 tab.

  7. Neutron capture therapy

    International Nuclear Information System (INIS)

    The overall state of the art related with neutron capture therapy(NCT) is surveyed. Since the field related with NCT is very wide, it is not intended to survey all related subjects in depth. The primary objective of this report is to help those working for the installation of a NCT facility and a PGNAA(prompt gamma ray neutron activation analysis) system for the boron analysis understand overall NCT at Hanaro. Therefore, while the parts of reactor neutron source and PGNAA are dealt in detail, other parts are limited to the level necessary to understand related fields. For example, the subject of chemical compound which requires intensive knowledge on chemistry, is not dealt as a separated item. However, the requirement of a compound for NCT, currently available compounds, their characteristics, etc. could be understood through this report. Although the subject of cancer treated by NCT is out of the capability of the author, it is dealt focussing its characteristics related with the success of NCT. Each detailed subject is expected to be dealt more detail by specialists in future. This report would be helpful for the researchers working for the NCT to understand related fields. (author). 128 refs., 3 tabs., 12 figs

  8. Study of photoionization and dissociative photoionization of carbon monoxide from ionization threshold to 38 eV by using synchrotron radiation

    International Nuclear Information System (INIS)

    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 (Ed) of possible dissociative channels are in reasonable agreement with the calculated values of the proposed photodissociation channels

  9. Capturing Common Loons during prenesting and nesting periods

    Science.gov (United States)

    Kenow, K.P.; Wilson, J.M.; Meyer, M.W.

    2009-01-01

    Several techniques have been used to capture Common Loons (Gavia immer), but effectiveness is limited during periods of the breeding season when loons do not have chicks. From 2005 to 2008, we studied loons in northern Wisconsin and used night lighting to capture loons on nests and also designed a lift net for capturing loons prior to nesting. At night, incubating loons were approached by boat and, when within about 30-60 m, we focused a spotlight on the loon and, once at the nest, captured loons using a landing net. Using this technique, we captured 23 loons in 29 attempts (79%). In addition, taped calls and loon decoys were used to entice prenesting, territorial loons into a shoreline-based, lift-net trap at a capture efficiency of 67% (10 captures in 15 attempts) during the second year of use. Our diurnal lift-net trap and night-light nest-capture techniques allowed us to capture adult Common Loons during periods of the breeding season when previous investigators have found loons difficult to catch. These techniques may also be useful for capturing other species of territorial waterbirds, especially other species of loons. ?? 2009 Association of Field Ornithologists. No claim to original U.S. government works.

  10. Revisiting the issue of elite capture in participatory initiatives

    DEFF Research Database (Denmark)

    Lund, Jens Friis; Saito-Jensen, Moeko

    2013-01-01

    resistance orchestrated by initially disadvantaged groups. Based on the cases we argue that studies of elite capture should be based on in-depth and longitudinal empirical investigations that carefully characterize forms and outcomes of elite capture and consider both the changing dynamics of social settings...

  11. A preliminary study of cortisol and norepinephrine reactivity to psychosocial stress in borderline personality disorder with high and low dissociation.

    Science.gov (United States)

    Simeon, Daphne; Knutelska, Margaret; Smith, Lisa; Baker, Bryann R; Hollander, Eric

    2007-01-15

    The goal of the current study was to investigate subjective and neurohormonal reactivity to acute psychosocial stress in borderline personality disorder (BPD) as a function of dissociative symptoms. Five BPD subjects with high dissociation, 8 BPD subjects with low dissociation, and 11 healthy control subjects were compared in basal urinary cortisol and norepinephrine, as well as in plasma cortisol and norepinephrine reactivity to the Trier Social Stress Test (TSST). Subjective stress rating and emotional response to the TSST were also measured. The three groups differed significantly in cortisol stress reactivity, with the high-dissociation BPD group demonstrating the most robust response. The three groups did not significantly differ in norepinephrine stress reactivity. In the combined BPD sample, dissociation severity tended to be inversely correlated with basal urinary norepinephrine, was positively correlated with norepinephrine stress reactivity. Childhood trauma was inversely correlated with basal urinary cortisol. In conclusion, despite its small sample size this pilot study suggests that dissociative symptomatology may be a marker of heightened biological vulnerability to stress in BPD, and merits further study. PMID:17169436

  12. 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

  13. On the valence model for radiative capture

    International Nuclear Information System (INIS)

    We give several parametrizations for the elastic scattering and radiative capture cross sections for low neutron bombarding energy and discuss the relationship between the corresponding resonance parameters. We then peform an extensive investigation of the valence radiative capture model of Lane and Lynn. This model is formulated here in the frame of the shell-model approach. We exhibit the similarities and differences between our results and those derived from the R-matrix approach by Lane and Lynn on the one hand and from the optical-model approach by Lane and Mughabghab on the other hand. Particular attention is paid to the choice of the average potential well in the shell model approach, in relation to the proper way to identify theoretical quantities and phenomenological parameters. We show that practically equivalent results can be obtained from a complex average potential well and from a suitably chosen real potential well. The following topics are investigated formally and numerically: dependence of the various theoretical expressions on the choice of the (real or complex) average potential well; relative importance of external and internal capture; dependence of photon widths and background cross section on mass number (for thermal energy and for E=100 keV); dependence of the resonance parameters and background cross sections on energy, for A=60; comparison between experimental data and theoretical values for radiative capture on 56Fe and 60Ni. We discuss the conditions of validity of the valence capture model The contribution of the low-lying excited target states is investigated formally and numerically

  14. Modelling of cyclopentane promoted gas hydrate systems for carbon dioxide capture processes

    DEFF Research Database (Denmark)

    Herslund, Peter Jørgensen; Thomsen, Kaj; Abildskov, Jens;

    2014-01-01

    A thermodynamic model based on the Cubic-Plus-Association equation of state and the van der Waals-Platteeuw hydrate model is applied to perform a thermodynamic evaluation of gas hydrate forming systems relevant for post-combustion carbon dioxide capture.A modelling study of both fluid phase...... first stage is estimated to be 24.9. MPa. Applying three consecutive hydrate formation/dissociation stages (three-stage capture process), a carbon dioxide-rich product (97. mol%) may be delivered at a temperature of 280. K and a pressure of 3.65. MPa.A second capture process, where cyclopentane is...... study suggests the hydrate-based separation technology to be unsuitable for the specific case of post-combustion carbon dioxide capture from power station flue gases, where operating pressures should preferably remain close to atmospheric. Even though the hydrate structure becomes available at low...

  15. Coulomb dissociation of light unstable nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kido, Toshihiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yabana, Kazuhiro; Suzuki, Yoshiyuki

    1997-05-01

    The aim of this study is that a simulation method applicable to the atomic nucleus with neutron halo structure developed till now is applied to a wider range unstable nucleus containing proton excess nucleus to also attribute understanding of nuclear reaction with interest in astronomical nuclear reaction. The proton dissociation energy in {sup 8}B nucleus is small value of 138 eV, which is thought to have a structure of proton at the most outer shell bound much weakly by core nucleus and spread in thinner thickness. For the coulomb excitation of such weak bound system, quantum theoretical and non-perturbational treatment is important. Therefore, 3-dimensional time-dependent Schroedinger equation on relative wave function of the core nucleus {sup 7}Be and halo proton p will be dissolved in time space and will execute a time developmental simulation. (G.K.)

  16. Direct dissociative chemisorption of propane on Ir(110)

    International Nuclear Information System (INIS)

    We have employed molecular beam techniques to investigate the initial probability of direct dissociative chemisorption, Pd, and the intrinsic trapping probability, ξ, of C3H8, C3D8, and (CH3)2CD2 on Ir(110) as a function of beam translational energy, Ei, from 1.5 to 59 kcal/mol. For C3H8 and (CH3)2CD2, a measurable (≥0.02) initial probability of direct dissociative chemisorption is observed above a beam energy of approximately 7 kcal/mol. For C3D8 this energy is roughly 10 kcal/mol. Above these energies the initial probability of direct chemisorption of each of the isotopomers of propane increases nearly linearly with Ei, approaching a value of approximately Pd=0.48 at Ei=52 kcal/mol for C3H8 and (CH3)2CD2, and Pd=0.44 at Ei=59 kcal/mol for C3D8. This kinetic isotope effect for the direct chemisorption of C3D8 relative to C3H8 is smaller than that expected for a mechanism of H (or D) abstraction by tunneling through an Eckart barrier, suggesting a contribution of C endash C bond cleavage to direct chemisorption. The lack of a kinetic isotope effect for the direct chemisorption of (CH3)2CD2 relative to C3H8 indicates that 1 degree C endash H bond cleavage dominates over 2 degree C endash H bond cleavage during the direct chemisorption of propane on Ir(110). The trapping behavior of each of these isotopomers of propane is approximately identical as a function of Ei, with ξ>0.9 at Ei=1.5 kcal/mol, ξ=0.3 at Ei=20 kcal/mol, and ξi=40 kcal/mol. copyright 1996 American Institute of Physics

  17. Thomas-forbidden particle capture

    OpenAIRE

    Carter, John H.; Lieber, Michael

    2010-01-01

    At high energies, in particle-capture processes between ions and atoms, classical kinematic requirements show that generally double collision Thomas processes dominate. However, for certain mass-ratios these processes are kinematically forbidden. This paper explores the possibility of capture for such processes by triple or higher order collision processes.

  18. Switch Function and Pathological Dissociation in Acute Psychiatric Inpatients

    Science.gov (United States)

    Chiu, Chui-De; Tseng, Mei-Chih Meg; Chien, Yi-Ling; Liao, Shih-Cheng; Liu, Chih-Min; Yeh, Yei-Yu; Hwu, Hai-Gwo

    2016-01-01

    Swift switching, along with atypical ability on updating and inhibition, has been found in non-clinical dissociators. However, whether swift switching is a cognitive endophenotype that intertwines with traumatisation and pathological dissociation remains unknown. Unspecified acute psychiatric patients were recruited to verify a hypothesis that pathological dissociation is associated with swift switching and traumatisation may explain this relationship. Behavioural measures of intellectual function and three executive functions including updating, switching and inhibition were administered, together with standardised scales to evaluate pathological dissociation and traumatisation. Our results showed superior control ability on switching and updating in inpatients who displayed more symptoms of pathological dissociation. When all three executive functions were entered as predictors, in addition to intellectual quotient and demographic variables to regress upon pathological dissociation, switching rather than updating remained the significant predictor. Importantly, the relationship between pathological dissociation and switching became non-significant when the effect of childhood trauma were controlled. The results support a trauma-related switching hypothesis which postulates swift switching as a cognitive endophenotype of pathological dissociation; traumatisation in childhood may explain the importance of swift switching. PMID:27123578

  19. RAIRS observation of photoinduced dissociation of NO on Ni(111)

    Science.gov (United States)

    Magkoev, Tamerlan T.; Song, Moon-Bong; Fukutani, Katsuyuki; Murata, Yoshitada

    1995-06-01

    The properties of the {NO}/{Ni(111) } system under nanosecond ultraviolet laser light irradiation are studied by reflection absorption infrared spectroscopy. It is found that adsorbed NO molecules are dissociated by laser light. Dissociation proceeds effectively in a dilute NO layer, whereas it is suppressed in a saturated overlayer.

  20. Structure sensitivity of CO dissociation on Rh surfaces

    DEFF Research Database (Denmark)

    Mavrikakis, Manos; Baumer, M.; Freund, H.J.; Nørskov, Jens Kehlet

    Using periodic self-consistent density functional calculations it is shown that the barrier for CO dissociation is similar to120 kJ/mol lower on the stepped Rh(211) surface than on the close-packed Rh(111) surface. The stepped surface binds molecular CO and the dissociation products more strongly...

  1. Dissociation and Decay of Ultra-cold Sodium Molecules

    OpenAIRE

    Mukaiyama, T.; Abo-Shaeer, J. R.; Xu, K.; Chin, J. K.; Ketterle, W.

    2003-01-01

    The dissociation of ultracold molecules is studied by ramping an external magnetic field through a Feshbach resonance. The observed dissociation energy shows non-linear dependence on the ramp speed and directly yields the strength of the atom-molecule coupling. In addition, inelastic molecule-molecule and molecule-atom collisions are characterized.

  2. 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)

  3. Nitrogen absorption and dissociation on small Tantalum clusters

    International Nuclear Information System (INIS)

    Using a first-principles PAW based technique we study the absorption of N2 on small Tan (n≤4) clusters and show that such clusters do dissociatively absorb N2 and are suitable candidates for catalysis in reactions which require dissociation of N2.

  4. Molecular dynamics - The dissociation of H2 by He.

    Science.gov (United States)

    Brown, N. J.; Munn, R. J.

    1972-01-01

    The dissociation of molecular hydrogen by helium was studied at 5500 deg K using the quasiclassical approximation. The temperature-dependent reaction cross sections were very dependent on the initial quantum states of the molecule. A rate constant was estimated for the dissociation reaction, and agreement between theory and experiment was satisfactory.

  5. Switch Function and Pathological Dissociation in Acute Psychiatric Inpatients.

    Directory of Open Access Journals (Sweden)

    Chui-De Chiu

    Full Text Available Swift switching, along with atypical ability on updating and inhibition, has been found in non-clinical dissociators. However, whether swift switching is a cognitive endophenotype that intertwines with traumatisation and pathological dissociation remains unknown. Unspecified acute psychiatric patients were recruited to verify a hypothesis that pathological dissociation is associated with swift switching and traumatisation may explain this relationship. Behavioural measures of intellectual function and three executive functions including updating, switching and inhibition were administered, together with standardised scales to evaluate pathological dissociation and traumatisation. Our results showed superior control ability on switching and updating in inpatients who displayed more symptoms of pathological dissociation. When all three executive functions were entered as predictors, in addition to intellectual quotient and demographic variables to regress upon pathological dissociation, switching rather than updating remained the significant predictor. Importantly, the relationship between pathological dissociation and switching became non-significant when the effect of childhood trauma were controlled. The results support a trauma-related switching hypothesis which postulates swift switching as a cognitive endophenotype of pathological dissociation; traumatisation in childhood may explain the importance of swift switching.

  6. 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…

  7. Dissociation predicts treatment response in eye-movement desensitization and reprocessing for posttraumatic stress disorder.

    Science.gov (United States)

    Bae, Hwallip; Kim, Daeho; Park, Yong Chon

    2016-01-01

    Using clinical data from a specialized trauma clinic, this study investigated pretreatment clinical factors predicting response to eye-movement desensitization and reprocessing (EMDR) among adult patients diagnosed with posttraumatic stress disorder (PTSD). Participants were evaluated using the Clinician-Administered PTSD Scale (CAPS), the Symptom Checklist-90-Revised, the Beck Depression Inventory, and the Dissociative Experiences Scale before treatment and were reassessed using the CAPS after treatment and at 6-month follow-up. A total of 69 patients underwent an average of 4 sessions of EMDR, and 60 (87%) completed the posttreatment evaluation, including 8 participants who terminated treatment prematurely. Intent-to-treat analysis revealed that 39 (65%) of the 60 patients were classified as responders and 21 (35%) as nonresponders when response was defined as more than a 30% decrease in total CAPS score. The nonresponders had higher levels of dissociation (depersonalization and derealization) and numbing symptoms, but other PTSD symptoms, such as avoidance, hyperarousal, and intrusion, were not significantly different. The number of psychiatric comorbidities was also associated with treatment nonresponse. The final logistic regression model yielded 2 significant variables: dissociation (p < .001) and more than 2 comorbidities compared to none (p < .05). These results indicate that complex symptom patterns in PTSD may predict treatment response and support the inclusion of the dissociative subtype of PTSD in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. PMID:26156867

  8. Peritraumatic Distress and Dissociation in Prolonged Grief and Posttraumatic Stress Following Violent and Unexpected Deaths.

    Science.gov (United States)

    Boelen, Paul A

    2015-01-01

    This study examined associations between the violence of a loss and the suddenness of a loss and symptom levels of prolonged grief disorder (PGD) and posttraumatic stress disorder (PTSD) after the death of a loved one. A further aim was to investigate whether peritraumatic distress (i.e., fear, helplessness, and horror) and peritraumatic dissociation mediate the emotional impact of violent losses and unexpected losses. We obtained self-reported data from 265 individuals bereaved in the previous 3 years by losses due to violent causes (17%) or illness (83%). Outcomes showed that participants who experienced violent losses (due to homicide, suicide, or accident) reported more PGD symptoms and PTSD symptoms compared to those confronted with illness loss. In this latter group, greater perceived unexpectedness was positively associated with PGD severity and PTSD severity. Multiple mediation analyses showed that the impact of violent loss and unexpectedness of the loss on PGD severity and PTSD severity was fully mediated by peritraumatic distress and dissociation; peritraumatic helplessness and peritraumatic dissociation (but not peritraumatic fear and horror) emerged as unique mediators. Findings suggest that both violent and unexpected losses exacerbate postloss psychopathology, which is at least partially because of such losses yielding more intense acute helplessness and dissociative responses. PMID:26156555

  9. Evolution of Hydrate Dissociation by Warm Brine Stimulation Combined Depressurization in the South China Sea

    Directory of Open Access Journals (Sweden)

    Zhao-Yang Chen

    2013-10-01

    Full Text Available To evaluate the gas production performance of the hydrate accumulations in the South China Sea, a numerical simulation with warm brine stimulation combined depressurization has been conducted. A dual horizontal well system is considered as the well configuration in this work. In order to reduce energy input and improve energy utilization, warm brine (50 °C is injected into the reservoir for hydrate dissociation. The effect of the intrinsic permeability of the hydrate reservoir, the salinity and the temperature of the injected brine to gas hydrate exploitation have been investigated. The numerical simulation results indicate that the average gas production rate Qavg is about 1.23 ´ 105 ST m3/day for the entire hydrate deposit, which has the same order of magnitude compared with the commercially viable production rate. The injected brine can be pumped out from the upper production well directly after the hydrate between the two wells is dissociated completely. Thus, the effective region of heat and inhibitor stimulation is limited. The sensitivity analyses indicate that the dissociation rate of hydrate can be enhanced by increasing the temperature of the injected brine and raising the salinity of the injected brine. The parametric study of permeability shows that the hydrate of the reservoir with the larger permeability has a higher dissociation rate.

  10. Strain effect on the adsorption, diffusion, and molecular dissociation of hydrogen on Mg (0001) surface

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Huaping; Wang, Caizhuang; Yao, Yongxin; Hupalo, Myron [Ames Laboratory, USDOE, Ames, Iowa 50011 (United States); Wang, Yangang [Ames Laboratory, USDOE, Ames, Iowa 50011 (United States); Supercomputing Center of Computer Network Information Center, CAS, Beijing 100190 (China); McDougall, Dan; Tringides, Michael; Ho, Kaiming [Ames Laboratory, USDOE, Ames, Iowa 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)

    2013-12-14

    The adsorption, diffusion, and molecular dissociation of hydrogen on the biaxially strained Mg (0001) surface have been systematically investigated by the first principle calculations based on density functional theory. When the strain changes from the compressive to tensile state, the adsorption energy of H atom linearly increases while its diffusion barrier linearly decreases oppositely. The dissociation barrier of H{sub 2} molecule linearly reduces in the tensile strain region. Through the chemical bonding analysis including the charge density difference, the projected density of states and the Mulliken population, the mechanism of the strain effect on the adsorption of H atom and the dissociation of H{sub 2} molecule has been elucidated by an s-p charge transfer model. With the reduction of the orbital overlap between the surface Mg atoms upon the lattice expansion, the charge transfers from p to s states of Mg atoms, which enhances the hybridization of H s and Mg s orbitals. Therefore, the bonding interaction of H with Mg surface is strengthened and then the atomic diffusion and molecular dissociation barriers of hydrogen decrease accordingly. Our works will be helpful to understand and to estimate the influence of the lattice deformation on the performance of Mg-containing hydrogen storage materials.

  11. Methane hydrate dissociation using inverted five-spot water flooding method in cubic hydrate simulator

    International Nuclear Information System (INIS)

    The combination forms of the hydrate dissociation methods in different well systems are divided into 6 main patterns. Dissociation processes of methane hydrate in porous media using the inverted five-spot water flooding method (Pattern 4) are investigated by the experimental observation and numerical simulation. In situ methane hydrate is synthesized in the Cubic Hydrate Simulator (CHS), a 5.832-L cubic reactor. A center vertical well is used as the hot water injection well, while the four vertical wells at the corner are the gas and water production wells. The gas production begins simultaneously with the hot water injection, while after approximately 20 min of compression, the water begins to be produced. One of the common characteristics of the inverted five-spot water flooding method is that both the gas and water production rates decrease with the reduction of the hydrate dissociation rate. The evaluation of the energy efficiency ratio might indicate the inverted five-spot water flooding as a promising gas producing method from the hydrate reservoir. - Highlights: • A three-dimensional 5.8-L cubic pressure vessel is developed. • Gas production of hydrate using inverted five-spot flooding method is studied. • Water/gas production rate and energy efficiency ratio are evaluated. • Temperature distributions of numerical simulation and experiment agree well. • Hydrate dissociation process is a moving boundary problem in this study

  12. Adaptive Multilevel Splitting Method for Molecular Dynamics Calculation of Benzamidine-Trypsin Dissociation Time.

    Science.gov (United States)

    Teo, Ivan; Mayne, Christopher G; Schulten, Klaus; Lelièvre, Tony

    2016-06-14

    Adaptive multilevel splitting (AMS) is a rare event sampling method that requires minimal parameter tuning and allows unbiased sampling of transition pathways of a given rare event. Previous simulation studies have verified the efficiency and accuracy of AMS in the calculation of transition times for simple systems in both Monte Carlo and molecular dynamics (MD) simulations. Now, AMS is applied for the first time to an MD simulation of protein-ligand dissociation, representing a leap in complexity from the previous test cases. Of interest is the dissociation rate, which is typically too low to be accessible to conventional MD. The present study joins other recent efforts to develop advanced sampling techniques in MD to calculate dissociation rates, which are gaining importance in the pharmaceutical field as indicators of drug efficacy. The system investigated here, benzamidine bound to trypsin, is an example common to many of these efforts. The AMS estimate of the dissociation rate was found to be (2.6 ± 2.4) × 10(2) s(-1), which compares well with the experimental value. PMID:27159059

  13. Molecular dynamics simulation of ligand dissociation from liver fatty acid binding protein.

    Directory of Open Access Journals (Sweden)

    Dong Long

    Full Text Available The mechanisms of how ligands enter and leave the binding cavity of fatty acid binding proteins (FABPs have been a puzzling question over decades. Liver fatty acid binding protein (LFABP is a unique family member which accommodates two molecules of fatty acids in its cavity and exhibits the capability of interacting with a variety of ligands with different chemical structures and properties. Investigating the ligand dissociation processes of LFABP is thus a quite interesting topic, which however is rather difficult for both experimental approaches and ordinary simulation strategies. In the current study, random expulsion molecular dynamics simulation, which accelerates ligand motions for rapid dissociation, was used to explore the potential egress routes of ligands from LFABP. The results showed that the previously hypothesized "portal region" could be readily used for the dissociation of ligands at both the low affinity site and the high affinity site. Besides, one alternative portal was shown to be highly favorable for ligand egress from the high affinity site and be related to the unique structural feature of LFABP. This result lends strong support to the hypothesis from the previous NMR exchange studies, which in turn indicates an important role for this alternative portal. Another less favored potential portal located near the N-terminal end was also identified. Identification of the dissociation pathways will allow further mechanistic understanding of fatty acid uptake and release by computational and/or experimental techniques.

  14. Molecular dynamics simulation of ligand dissociation from liver fatty acid binding protein.

    Science.gov (United States)

    Long, Dong; Mu, Yuguang; Yang, Daiwen

    2009-01-01

    The mechanisms of how ligands enter and leave the binding cavity of fatty acid binding proteins (FABPs) have been a puzzling question over decades. Liver fatty acid binding protein (LFABP) is a unique family member which accommodates two molecules of fatty acids in its cavity and exhibits the capability of interacting with a variety of ligands with different chemical structures and properties. Investigating the ligand dissociation processes of LFABP is thus a quite interesting topic, which however is rather difficult for both experimental approaches and ordinary simulation strategies. In the current study, random expulsion molecular dynamics simulation, which accelerates ligand motions for rapid dissociation, was used to explore the potential egress routes of ligands from LFABP. The results showed that the previously hypothesized "portal region" could be readily used for the dissociation of ligands at both the low affinity site and the high affinity site. Besides, one alternative portal was shown to be highly favorable for ligand egress from the high affinity site and be related to the unique structural feature of LFABP. This result lends strong support to the hypothesis from the previous NMR exchange studies, which in turn indicates an important role for this alternative portal. Another less favored potential portal located near the N-terminal end was also identified. Identification of the dissociation pathways will allow further mechanistic understanding of fatty acid uptake and release by computational and/or experimental techniques. PMID:19564911

  15. The molecular dynamics of adsorption and dissociation of O2 on Pt(553)

    International Nuclear Information System (INIS)

    Molecular adsorption and dissociation of O2 on the stepped Pt(553) surface have been investigated using supersonic molecular beam techniques and temperature programmed desorption. The initial and coverage-dependent sticking probability was determined with the King and Wells technique for various combinations of incident kinetic energy, surface temperature, incident angle, and surface coverage. A comparison with similar data for Pt(533) and Pt(110)(1 × 2) shows quantitatively the same high step-induced sticking at low incident energies compared to Pt(111). The enhancement is therefore insensitive to the exact arrangement of atoms forming surface corrugation. We consider energy transfer and electronic effects to explain the enhanced sticking. On the other hand, dissociation dynamics at higher incident kinetic energies are strongly dependent on step type. The Pt(553) and Pt(533) surfaces are more reactive than Pt(111), but the (100) step shows higher sticking than the (110) step. We relate this difference to a variation in the effective lowering of the barrier to dissociation from molecularly adsorbed states into atomic states. Our findings are in line with results from experimental desorption studies and theoretical studies of atomic binding energies. We discuss the influence of the different step types on sticking and dissociation dynamics with a one-dimensional potential energy surface

  16. Strain effect on the adsorption, diffusion, and molecular dissociation of hydrogen on Mg (0001) surface.

    Science.gov (United States)

    Lei, Huaping; Wang, Caizhuang; Yao, Yongxin; Wang, Yangang; Hupalo, Myron; McDougall, Dan; Tringides, Michael; Ho, Kaiming

    2013-12-14

    The adsorption, diffusion, and molecular dissociation of hydrogen on the biaxially strained Mg (0001) surface have been systematically investigated by the first principle calculations based on density functional theory. When the strain changes from the compressive to tensile state, the adsorption energy of H atom linearly increases while its diffusion barrier linearly decreases oppositely. The dissociation barrier of H2 molecule linearly reduces in the tensile strain region. Through the chemical bonding analysis including the charge density difference, the projected density of states and the Mulliken population, the mechanism of the strain effect on the adsorption of H atom and the dissociation of H2 molecule has been elucidated by an s-p charge transfer model. With the reduction of the orbital overlap between the surface Mg atoms upon the lattice expansion, the charge transfers from p to s states of Mg atoms, which enhances the hybridization of H s and Mg s orbitals. Therefore, the bonding interaction of H with Mg surface is strengthened and then the atomic diffusion and molecular dissociation barriers of hydrogen decrease accordingly. Our works will be helpful to understand and to estimate the influence of the lattice deformation on the performance of Mg-containing hydrogen storage materials. PMID:24329077

  17. Strain effect on the adsorption, diffusion, and molecular dissociation of hydrogen on Mg (0001) surface

    International Nuclear Information System (INIS)

    The adsorption, diffusion, and molecular dissociation of hydrogen on the biaxially strained Mg (0001) surface have been systematically investigated by the first principle calculations based on density functional theory. When the strain changes from the compressive to tensile state, the adsorption energy of H atom linearly increases while its diffusion barrier linearly decreases oppositely. The dissociation barrier of H2 molecule linearly reduces in the tensile strain region. Through the chemical bonding analysis including the charge density difference, the projected density of states and the Mulliken population, the mechanism of the strain effect on the adsorption of H atom and the dissociation of H2 molecule has been elucidated by an s-p charge transfer model. With the reduction of the orbital overlap between the surface Mg atoms upon the lattice expansion, the charge transfers from p to s states of Mg atoms, which enhances the hybridization of H s and Mg s orbitals. Therefore, the bonding interaction of H with Mg surface is strengthened and then the atomic diffusion and molecular dissociation barriers of hydrogen decrease accordingly. Our works will be helpful to understand and to estimate the influence of the lattice deformation on the performance of Mg-containing hydrogen storage materials

  18. Effects of thermodynamic inhibitors on the dissociation of methane hydrate: a molecular dynamics study.

    Science.gov (United States)

    Yagasaki, Takuma; Matsumoto, Masakazu; Tanaka, Hideki

    2015-12-28

    We investigate the effects of methanol and NaCl, which are known as thermodynamic hydrate inhibitors, on the dissociation kinetics of methane hydrate in aqueous solutions by using molecular dynamics simulations. It is shown that the dissociation rate is not constant but changes with time. The dissociation rate in the initial stage is increased by methanol whereas it is decreased by NaCl. This difference arises from the opposite effects of the two thermodynamic inhibitors on the hydration free energy of methane. The dissociation rate of methane hydrate is increased by the formation of methane bubbles in the aqueous phase because the bubbles absorb surrounding methane molecules. It is found that both methanol and NaCl facilitate the bubble formation. However, their mechanisms are completely different from each other. The presence of ions enhances the hydrophobic interactions between methane molecules. In addition, the ions in the solution cause a highly non-uniform distribution of dissolved methane molecules. These two effects result in the easy formation of bubbles in the NaCl solution. In contrast, methanol assists the bubble formation because of its amphiphilic character. PMID:26587576

  19. Neutron capture reactions at DANCE

    International Nuclear Information System (INIS)

    The Detector for Advanced Neutron Capture Experiments (DANCE) is a 4π BaF2 array consisting of 160 active detector elements. The primary purpose of the array is to perform neutron capture cross section measurements on small (> or approx.100 μg) and/or radioactive (241,243Am, neutron capture and neutron-induced fission cross sections and capture-to-fission ratio (α = σγ/σf) for 235U using a new fission-tagging detector as well as neutron capture cross sections for several astrophysics branch-point nuclei. Results from several of these measurements will be presented along with a discussion of additional physics information that can be extracted from the DANCE data

  20. Controllable dissociations of PH3 molecules on Si(001)

    Science.gov (United States)

    Liu, Qin; Lei, Yanhua; Shao, Xiji; Ming, Fangfei; Xu, Hu; Wang, Kedong; Xiao, Xudong

    2016-04-01

    We demonstrate for the first time to our knowledge that controllable dissociation of PH3 adsorption products PH x (x = 2, 1) can be realized by STM (scanning tunneling microscope) manipulation techniques at room temperature. Five dissociative products and their geometric structures are identified via combining STM experiments and first-principle calculations and simulations. In total we realize nine kinds of controllable dissociations by applying a voltage pulse among the PH3-related structures on Si(001). The dissociation rates of the five most common reactions are measured by the I-t spectrum method as a function of voltage. The suddenly increased dissociation rate at 3.3 V indicates a transition from multivibrational excitation to single-step excitation induced by inelastic tunneling electrons. Our studies prove that selectively breaking the chemical bonds of a single molecule on semiconductor surface by STM manipulation technique is feasible.

  1. IV. Dissociative recombination of electrons and molecular ions

    International Nuclear Information System (INIS)

    The present state of the theory of the dissociative recombination of electrons and molecular ions is reviewed and its shortcomings shown. The mechanisms of direct and indirect dissociative processes are described. Several approximative methods employing the analogy with the recombination of atomic ions and electrons are used for the determination of the dissociative recombination factor. Analyzing the derived formulae the temperature dependence of the dissociative recombination factor is determined and the results are compared with experimental data obtained by several authors. The energy levels of atoms created at the dissociative recombination of He2+, Ar2+, and O2+ ions are described. Methods of measuring the recombination factor are listed. The existing experimental data are summarized and the possible explanation of the observed variations is presented. An exhaustive list of references is given. (J.U.)

  2. Dissociation of methane hydrate in aqueous NaCl solutions.

    Science.gov (United States)

    Yagasaki, Takuma; Matsumoto, Masakazu; Andoh, Yoshimichi; Okazaki, Susumu; Tanaka, Hideki

    2014-10-01

    Molecular dynamics simulations of the dissociation of methane hydrate in aqueous NaCl solutions are performed. It is shown that the dissociation of the hydrate is accelerated by the formation of methane bubbles both in NaCl solutions and in pure water. We find two significant effects on the kinetics of the hydrate dissociation by NaCl. One is slowing down in an early stage before bubble formation, and another is swift bubble formation that enhances the dissociation. These effects arise from the low solubility of methane in NaCl solution, which gives rise to a nonuniform spatial distribution of solvated methane in the aqueous phase. We also demonstrate that bubbles form near the hydrate interface in dense NaCl solutions and that the hydrate dissociation proceeds inhomogeneously due to the bubbles. PMID:25237735

  3. CO2 Dissociation using the Versatile Atmospheric Dielectric Barrier Discharge Experiment (VADER)

    Science.gov (United States)

    Lindon, Michael Allen

    As of 2013, the Carbon Dioxide Information Analysis Center (CDIAC) estimates that the world emits approximately 36 trillion metric tons of Carbon Dioxide (CO2) into the atmosphere every year. These large emissions have been correlated to global warming trends that have many consequences across the globe, including glacial retraction, ocean acidification and increased severity of weather events. With green technologies still in the infancy stage, it can be expected that CO2 emissions will stay this way for along time to come. Approximately 41% of the emissions are due to electricity production, which pump out condensed forms of CO2. This danger to our world is why research towards new and innovative ways of controlling CO2 emissions from these large sources is necessary. As of now, research is focused on two primary methods of CO2 reduction from condensed CO2 emission sources (like fossil fuel power plants): Carbon Capture and Sequestration (CCS) and Carbon Capture and Utilization (CCU). CCS is the process of collecting CO2 using absorbers or chemicals, extracting the gas from those absorbers and finally pumping the gas into reservoirs. CCU on the other hand, is the process of reacting CO2 to form value added chemicals, which can then be recycled or stored chemically. A Dielectric Barrier discharge (DBD) is a pulsed, low temperature, non-thermal, atmospheric pressure plasma which creates high energy electrons suitable for dissociating CO2 into its components (CO and O) as one step in the CCU process. Here I discuss the viability of using a DBD for CO2 dissociation on an industrial scale as well as the fundamental physics and chemistry of a DBD for CO2 dissociation. This work involved modeling the DBD discharge and chemistry, which showed that there are specific chemical pathways and plasma parameters that can be adjusted to improve the CO2 reaction efficiencies and rates. Experimental studies using the Versatile Atmospheric dielectric barrier Discharge Expe

  4. 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.

    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 ar

  5. Materials For Gas Capture, Methods Of Making Materials For Gas Capture, And Methods Of Capturing Gas

    KAUST Repository

    Polshettiwar, Vivek

    2013-06-20

    In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, embodiments of the present disclosure, in one aspect, relate to materials that can be used for gas (e.g., CO.sub.2) capture, methods of making materials, methods of capturing gas (e.g., CO.sub.2), and the like, and the like.

  6. Resonant capture by inward migrating planets

    CERN Document Server

    Yu, Q; Tremaine, Scott

    2001-01-01

    We investigate resonant capture of small bodies by planets that migrate inwards, using analytic arguments and three-body integrations. If the orbits of the planet and the small body are initially circular and coplanar, the small body is captured when it crosses the 2:1 resonance with the planet. As the orbit shrinks it becomes more eccentric, until by the time its semimajor axis has shrunk by a factor of four, its eccentricity reaches nearly unity (1-e<<10^{-4}). In typical planetary systems, bodies in this high-eccentricity phase are likely to be consumed by the central star. If they can avoid this fate, as migration continues the inclination flips from 0 to i=180 degrees; thereafter the eccentricity declines until the semimajor axis is a factor of nine smaller than at capture, at which point the small body is released from the 2:1 resonance on a nearly circular retrograde orbit. Small bodies captured into resonance from initially inclined or eccentric orbits can also be ejected from the system, or rel...

  7. Neutron capture cross sections from Surrogate measurements

    OpenAIRE

    Scielzo N.D.; Dietrich F.S.; Escher J.E.

    2010-01-01

    The prospects for determining cross sections for compound-nuclear neutron-capture reactions from Surrogate measurements are investigated. Calculations as well as experimental results are presented that test the Weisskopf-Ewing approximation, which is employed in most analyses of Surrogate data. It is concluded that, in general, one has to go beyond this approximation in order to obtain (n,γ) cross sections of sufficient accuracy for most astrophysical and nuclear-energy applications.

  8. Neutron capture cross sections from Surrogate measurements

    Directory of Open Access Journals (Sweden)

    Scielzo N.D.

    2010-03-01

    Full Text Available The prospects for determining cross sections for compound-nuclear neutron-capture reactions from Surrogate measurements are investigated. Calculations as well as experimental results are presented that test the Weisskopf-Ewing approximation, which is employed in most analyses of Surrogate data. It is concluded that, in general, one has to go beyond this approximation in order to obtain (n,γ cross sections of sufficient accuracy for most astrophysical and nuclear-energy applications.

  9. Media Capture and Information Monopolization in Japan

    OpenAIRE

    Au, Pak Hung; Kawai, Keiichi

    2010-01-01

    In this paper, we investigate the unique institution of the Japanese press industry called kisha club system, which is deemed as the symbol of media capture by the government, and collusion in the media industry. By tracing through its history, we show how the institution has developed as a result of the government's attempt to control the media, and the media's incentive to use the alluring opportunity provided by the government to limit the rivalry within the industry. We find that the dist...

  10. A new method for capturing alligators using electricity

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A study was initiated on Rockefeller Wildlife Refuge in order to investigate the possibility of using an electrical current as an aid in capturing alligators. A...

  11. Dissociations of the night: individual differences in sleep-related experiences and their relation to dissociation and schizotypy.

    Science.gov (United States)

    Watson, D

    2001-11-01

    The author examined the associations among sleep-related experiences (e.g., hypnagogic hallucinations, nightmares, waking dreams, and lucid dreams), dissociation, schizotypy, and the Big Five personality traits in 2 large student samples. Confirmatory factor analyses indicated that (a) dissociation and schizotypy are strongly correlated-yet distinguishable-constructs, and (b) the differentiation between them can be enhanced by eliminating detachment/depersonalization items from the dissociation scales. A general measure of sleep experiences was substantially correlated with both schizotypy and dissociation (especially the latter) and more weakly related to the Big Five. In contrast, an index of lucid dreaming was weakly related to all of these other scales. These results suggest that measures of dissociation, schizotypy, and sleep-related experiences all define a common domain characterized by unusual cognitions and perceptions. PMID:11727942

  12. Molecular dynamics study of solvation effects on acid dissociation in aprotic media

    CERN Document Server

    Laria, D; Estrin, D A; Ciccotti, G; Laria, Daniel; Kapral, Raymond; Estrin, Dario; Ciccotti, Giovanni

    1996-01-01

    Acid ionization in aprotic media is studied using Molecular Dynamics techniques. In particular, models for HCl ionization in acetonitrile and dimethylsulfoxide are investigated. The proton is treated quantum mechanically using Feynman path integral methods and the remaining molecules are treated classically. Quantum effects are shown to be essential for the proper treatment of the ionization. The potential of mean force is computed as a function of the ion pair separation and the local solvent structure is examined. The computed dissociation constants in both solvents differ by several orders of magnitude which are in reasonable agreement with experimental results. Solvent separated ion pairs are found to exist in dimethylsulfoxide but not in acetonitrile. Dissociation mechanisms in small clusters are also investigated. Solvent separated ion pairs persist even in aggregates composed of rather few molecules, for instance, as few as thirty molecules. For smaller clusters or for large ion pair separations cluste...

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

    Science.gov (United States)

    Biderman, N. J.; Sundaramoorthy, R.; Haldar, Pradeep; Lloyd, J. R.

    2016-05-01

    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,Ga)Se2 (CIGS) and Cu2ZnSn(S, Se)4 (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.

  14. 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.

  15. Chernobyl fallout in small mammals captured in Sweden

    International Nuclear Information System (INIS)

    An investigation was carried out aimed at studying the contamination of small mammals (orders Rodentia and Insectivora) following the Chernobyl fallout. The animals were captured in three differently contaminated areas and, for control, in an area with negligible fallout. The results obtained show that the activity in the captured animals varied and depended on surface deposition. The differences between the species are investigated and the influence of feeding habits on the contamination levels are discussed. (orig.)

  16. Electron capture and fragmentation in Ar11+ + CO collisions

    International Nuclear Information System (INIS)

    Collisions between 3, 10, and 50 keV/q Ar11+ ions and CO molecules have been studied using the Macdonald Lab CRYEBIS. Coincidence time of flight was used to detect all recoil ions and a position sensitive detector was used to determine final projectile charge states. Single- and double-electron capture are much larger than ionization at these collision energies. The dominant recoil channel associated with the Ar10+ final state is the CO+ molecular ion. The main ion-pair channel is the C+ + O+ dissociation of CO2+ while higher charge states of the transient COq+ fall off rapidly. Charge states up to CO4+ are formed in the collision indicating that many electrons are captured, but only one (and sometimes two) is retained by the projectile. This is due to autoionization of the highly excited states occupied by the captured electrons. In general, the fragmentation pattern of the CO molecule resembles the fragmentation associated with ionization caused by fast highly charged ions. This is as expected, since both processes happen at large impact parameters

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

    International Nuclear Information System (INIS)

    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 3.0×1013 W/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. - Highlights: • Dissociation follows step-wise dissociation with no sign for Coulomb explosion. • CH3OH+, CH3O+, CH3+ form at 1.4×1013, 1.7×1013, 2.0×1013 W/cm2, respectively. • C+, CH+, CH2+, OH+, and O+ and the H+ is detected at 2.8⁎1013 W/cm2. • H2+ is detected at 3.0×1013 W/cm2. • Among all ions, only H+ was found to have angular anisotropic distribution

  18. Bibliography of molecular dissociation in heavy particle collisions, 1950--75

    International Nuclear Information System (INIS)

    This annotated bibliography lists published work on molecular dissociation in heavy particle collisions for the period 1950 to 1975. Sources include scientific journals, abstract compilations, conference proceedings, books, and reports. The bibliography is arranged alphabetically by author. Each entry indicates whether the work was experimental or theoretical, what energy range was covered, and what reactants were investigated. Following the bibliographical listing are indexes of reactants and authors

  19. Dissociative versus Associative Responses to Social Identity Threat: The Role of Consumer Self-Construal

    OpenAIRE

    Katherine White; Jennifer J. Argo; Jaideep Sengupta

    2012-01-01

    The current research examines the conditions under which consumers demonstrate associative versus dissociative responses to identity-linked products as a consequence of a social identity threat. Across four studies, the authors test the notion that reactions to social identity threat may be moderated by self-construal by examining subcultural differences in ethnic background, priming self-construal, and investigating cross-national differences in cultural background. Those with more independe...

  20. Modulation of Network Activity in Dissociated Hippocampal Cultures by Enzymatic Digestion of Extracellular Matrix

    OpenAIRE

    Mukhina I.V.; Vedunova М.V.; Sakharnova Т.А.; Dityatev А.E.

    2012-01-01

    To investigate the role of extracellular matrix in spontaneous neuronal network activity, we used microelectrode array technology and enzymatic treatment of hippocampal culture with hyaluronidase, which digests the major component of extracellular matrix, hyaluronic acid. Studies were performed using hippocampal cells that were dissociated from embryonic С57ВL6 mice (E18) and plated on microelectrode arrays (MEAs). Our findings revealed that hyaluronidase promoted seizure-like activity during...

  1. Spontaneous dissociation of a conjugated molecule on the Si(100) surface

    OpenAIRE

    Lin, Rong; Galili, Michael; Quaade, Ulrich; Brandbyge, Mads; Bjørnholm, Thomas; Esposti, A.D.; F. Biscarini; Stokbro, Kurt

    2002-01-01

    The adsorption mechanism of alpha-sexithiophene (alpha-6T) on the clean Si(100)-(2x1) surface has been investigated using scanning tunneling microscopy (STM) and first principles electronic structure calculations. We find that at submonolayer coverage, the alpha-6T molecules are not stable and dissociate into monomers. We observe two different configurations of the monomers and have discussed the corresponding adsorption geometries based on theoretical calculations. The calculations elucidate...

  2. 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 ...

  3. Catalytic water dissociation by greigite Fe3S4 surfaces: density functional theory study

    OpenAIRE

    Roldan, A.; de Leeuw, N. H.

    2016-01-01

    The iron sulfide mineral greigite, Fe3S4, has shown promising capability as a hydrogenating catalyst, in particular in the reduction of carbon dioxide to produce small organic molecules under mild conditions. We employed density functional theory calculations to investigate the {001},{011} and {111} surfaces of this iron thiospinel material, as well as the production of hydrogen ad-atoms from the dissociation of water molecules on the surfaces. We systematically analysed the adsorption geomet...

  4. Bibliography of molecular dissociation in heavy particle collisions, 1950--75

    Energy Technology Data Exchange (ETDEWEB)

    McDaniel, E.W.; Barnett, C.F.; Crandall, D.H.; Gilbody, H.B.; Kirkpatrick, M.I.; Phaneuf, R.A.; Thomas, E.W.

    1979-02-01

    This annotated bibliography lists published work on molecular dissociation in heavy particle collisions for the period 1950 to 1975. Sources include scientific journals, abstract compilations, conference proceedings, books, and reports. The bibliography is arranged alphabetically by author. Each entry indicates whether the work was experimental or theoretical, what energy range was covered, and what reactants were investigated. Following the bibliographical listing are indexes of reactants and authors.

  5. Evidence for broken ergodicity due to chemical alloying from the dissociation kinetics of binary clusters

    OpenAIRE

    Yurtsever, Ersin; Calvo, Florent

    2014-01-01

    The interplay between thermal relaxation and statistical dissociation in binary Morse clusters (AB)N has been investigated using numerical simulations and simple statistical approaches, for a variety of interaction parameters covering miscible and non-miscible regimes. While all clusters exhibit a core/shell phase separation pattern in their most stable, T = 0 structure, different melting mechanisms are identified depending on the ranges and their mismatch, including two-step melting of the s...

  6. Dissociative adsorption of methane on surface oxide structures of Pd-Pt alloys

    OpenAIRE

    Dianat, Arezoo; Seriani, Nicola; Ciacchi, Lucio Colombi; Pompe, Wolfgang; Cuniberti, Gianaurelio; Bobeth, Manfred

    2010-01-01

    The dissociative adsorption of methane on variously oxidized Pd, Pt and Pd-Pt surfaces is investigated using density-functional theory, as a step towards understanding the combustion of methane on these materials. For Pd-Pt alloys, models of surface oxide structures are built on the basis of known oxides on Pd and Pt. The methane adsorption energy presents large variations depending on the oxide structure and composition. Adsorption is endothermic on the bare Pd(111) metal surface as well as ...

  7. The dissociation of oxy-acids at elevated temperatures

    International Nuclear Information System (INIS)

    The heat capacities of dissociation for carbonic, bicarbonate, phosphoric, biphosphate, silicic, nitric, boric and bisulfate oxy-acids have been evaluated at temperatures up to 300 C using published dissociation constants, heat capacities and a model which explicitly accounts for both electrostatic and nonelectrostatic contributions to the thermodynamic properties of dissociation. The heat capacities calculated are independent of the entropies of dissociation or the chemical characteristics of the acids, and are the same for all acids of a given dissociation type (i.e. 1st, 2nd, etc.). The average deviation between measured and calculated log Ksub(T)'s is less than 0.05 log units in the temperature range from 25 to 300 C. Dissociation constants for acetic acid can be accurately calculated using the oxy-acid heat capacity expression. The heat capacities are used to calculate dissociation constants for the oxy-acids of Cr(VI), N(III), S(IV), S(II), Se(IV), Se(VI), As(III), As(V), Te(VI), Cl(I), Cl(III), I(V) and C1-C3 aliphatic acids to temperatures of 300 C. (author)

  8. Lunar Sulfur Capture System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Lunar Sulfur Capture System (LSCS) is an innovative method to recover sulfur compounds from lunar soil using sorbents derived primarily from in-situ resources....

  9. Value Capture for Transportation Finance

    OpenAIRE

    Zhirong (Jerry) Zhao; Michael Iacono; David Levinson

    2009-01-01

    As vehicles become more fuel-efficient and overall levels of travel stagnate in response to increases in fuel prices, conventional sources of revenue for transportation finance such as taxes on motor fuels have been put under increasing pressure. One potential replacement as a source of revenue is a set of policies collectively referred to as value capture policies. In contrast to fuel taxes and other instruments that impose charges on users of transportation networks, value capture policies ...

  10. Toward transformational carbon capture systems

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David C. [National Energy Technology Laboratory, U.S. Dept. of Energy, Pittsburgh PA (United States); Litynski, John T. [Office of Fossil Energy, U.S. Dept. of Energy, Washington DC (United States); Brickett, Lynn A. [National Energy Technology Laboratory, U.S. Dept. of Energy, Pittsburgh PA (United States); Morreale, Bryan D. [National Energy Technology Laboratory, U.S. Dept. of Energy, Pittsburgh PA (United States)

    2015-10-28

    This paper will briefly review the history and current state of Carbon Capture and Storage (CCS) research and development and describe the technical barriers to carbon capture. it will argue forcefully for a new approach to R&D, which leverages both simulation and physical systems at the laboratory and pilot scales to more rapidly move the best technoogies forward, prune less advantageous approaches, and simultaneously develop materials and processes.

  11. Context Capture in Software Development

    OpenAIRE

    Antunes, Bruno; Correia, Francisco; Gomes, Paulo

    2011-01-01

    The context of a software developer is something hard to define and capture, as it represents a complex network of elements across different dimensions that are not limited to the work developed on an IDE. We propose the definition of a software developer context model that takes into account all the dimensions that characterize the work environment of the developer. We are especially focused on what the software developer context encompasses at the project level and how it can be captured. T...

  12. Coulomb dissociation reactions on molybdenum isotopes for astrophysics applications

    Energy Technology Data Exchange (ETDEWEB)

    Ershova, Olga

    2012-03-09

    Within the present work, photodissociation reactions on {sup 100}Mo, {sup 93}Mo and {sup 92}Mo isotopes were studied by means of the Coulomb dissociation method at the LAND setup at GSI. As a result of the analysis of the present experiment, integrated Coulomb excitation cross sections of the {sup 100}Mo({gamma},n), {sup 100}Mo({gamma},2n), {sup 93}Mo({gamma},n) and {sup 92}Mo({gamma},n) reactions were determined. A second important topic of the present thesis is the investigation of the efficiency of the CsI gamma detector. The data taken with the gamma calibration sources shortly after the experiment were used for the investigation. In addition, a test experiment in refined conditions was conducted within the framework of this thesis. Numerous GEANT3 simulations of the detector were performed in order to understand various aspects of its performance. As a result, the efficiency of the detector was determined to be approximately a factor of 2 lower than the efficiency expected from the simulation. (orig.)

  13. State dissociation, human behavior, and consciousness.

    Science.gov (United States)

    Mahowald, Mark W; Cramer Bornemann, Michel A; Schenck, Carlos H

    2011-01-01

    Sleep is clearly not only a whole-brain or global phenomenon, but can also be a local phenomenon. This accounts for the fact that the primary states of being (wakefulness, NREM sleep, and REM sleep) are not necessarily mutually exclusive, and components of these states may appear in various combinations, with fascinating clinical consequences. Examples include: sleep inertia, narcolepsy, sleep paralysis, lucid dreaming, REM sleep behavior disorder, sleepwalking, sleep terrors, out-of-body experiences, and reports of alien abduction. The incomplete declaration of state likewise has implications for consciousness - which also has fluid boundaries. Fluctuations in the degree of consciousness are likely explained by abnormalities of a "spatial and temporal binding rhythm" which normally results in a unified conscious experience. Dysfunctional binding may play a role in anesthetic states, autism, schizophrenia, and neurodegenerative disorders. Further study of the broad spectrum of dissociated states of sleep and wakefulness that are closely linked with states of consciousness and unconsciousness by basic neuroscientists, clinicians, and members of the legal profession will provide scientific, clinical and therapeutic insights, with forensic implications. PMID:21906025

  14. Visuomotor Dissociation in Cerebral Scaling of Size.

    Directory of Open Access Journals (Sweden)

    Adriaan R E Potgieser

    Full Text Available 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 which 16 right-handed subjects copied geometric figures while the result of drawing remained out of sight. Either the size of the example figure varied while maintaining a constant size of drawing (visual incongruity or the size of the examples remained constant while subjects were instructed to make changes in size (motor incongruity. These incongruent were compared to congruent conditions. Statistical Parametric Mapping (SPM8 revealed brain activations related to size incongruity in the dorsolateral prefrontal and inferior parietal cortex, pre-SMA / anterior cingulate and anterior insula, dominant in the right hemisphere. This pattern represented simultaneous use of a 'resized' virtual template and actual picture information requiring spatial working memory, early-stage attention shifting and inhibitory control. Activations were strongest in motor incongruity while right pre-dorsal premotor activation specifically occurred in this condition. Visual incongruity additionally relied on a ventral visual pathway. Left ventral premotor activation occurred in all variably sized drawing while constant visuomotor size, compared to congruent size variation, uniquely activated the lateral occipital cortex additional to superior parietal regions. These results highlight size as a fundamental parameter in both general hand movement and movement guided by objects perceived in the context of surrounding 3D space.

  15. Visuomotor Dissociation in Cerebral Scaling of Size.

    Science.gov (United States)

    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 which 16 right-handed subjects copied geometric figures while the result of drawing remained out of sight. Either the size of the example figure varied while maintaining a constant size of drawing (visual incongruity) or the size of the examples remained constant while subjects were instructed to make changes in size (motor incongruity). These incongruent were compared to congruent conditions. Statistical Parametric Mapping (SPM8) revealed brain activations related to size incongruity in the dorsolateral prefrontal and inferior parietal cortex, pre-SMA / anterior cingulate and anterior insula, dominant in the right hemisphere. This pattern represented simultaneous use of a 'resized' virtual template and actual picture information requiring spatial working memory, early-stage attention shifting and inhibitory control. Activations were strongest in motor incongruity while right pre-dorsal premotor activation specifically occurred in this condition. Visual incongruity additionally relied on a ventral visual pathway. Left ventral premotor activation occurred in all variably sized drawing while constant visuomotor size, compared to congruent size variation, uniquely activated the lateral occipital cortex additional to superior parietal regions. These results highlight size as a fundamental parameter in both general hand movement and movement guided by objects perceived in the context of surrounding 3D space. PMID:26963705

  16. Properties of Earth's temporarily-captured flybys

    Science.gov (United States)

    Fedorets, Grigori; Granvik, Mikael

    2014-11-01

    In addition to the Moon, a population of small temporarily-captured NEOs is predicted to orbit the Earth. The definition of a natural Earth satellite is that it is on an elliptic geocentric orbit within 0.03 au from the Earth. The population is further divided into temporarily-captured orbiters (TCOs, or minimoons, making at least one full revolution around the Earth in a coordinate system co-rotating with the Sun) and temporarily-captured flybys (TCFs) which fail to make a full revolution, but are temporarily on an elliptic orbit around the Earth. Only one minimoon has been discovered to date, but it is expected that next generation surveys will be able to detect these objects regularly.Granvik et al. (2012) performed an extensive analysis of the behaviour of these temporarily-captured objects. One of the main results was that at any given moment there is at least one 1-meter-diameter minimoon in orbit around the Earth. However, the results of Granvik et al. (2012) raised questions considering the NES population such as the bimodality of the capture duration distribution and a distinctive lack of test particles within Earth's Hill sphere, which requires investigating the statistical properties also of the TCF population.In this work we confirm the population characteristics for minimoons described by Granvik et al. (2012), and extend the analysis to TCFs. For the calculations we use a Bulirsch-Stoer integrator implemented in the OpenOrb software package (Granvik et al. 2009). We study, e.g., the capture statistics, residence-time distributions, and steady-state properties of TCFs. Our preliminary results indicate that TCFs may be suitable targets for asteroid-redirect missions. More detailed knowledge of the TCF population will also improve our understanding of the link between temporarily-captured objects and NEOs in general.References: Granvik et al. (2009) MPS 44(12), 1853-1861; Granvik et al. (2012) Icarus 218, 262-277.

  17. Hydrophobic stabilization of chiton hemocyanins: effects of ureas, Hofmeister salts and pH on their dissociation.

    Science.gov (United States)

    Herskovits, T T; Hamilton, M G

    1987-09-24

    The subunit dissociation of the hemocyanins from five members of the Polyplacophora families, Acanthochitonidae, Callistoplacidae, Chitonidae, Ischnochitonidae and Mopalidae, represented by the chitons Cryptochiton stelleri, Nutallina fluxa, Acanthopleura granulata, Stenoplax conspicua and Mopalia mucosa, respectively, have been investigated by light-scattering molecular-weight and ultracentrifugation methods, using the hydrophobic reagents of the urea series and the Hofmeister salt series as probes of the contact areas of the hemocyanin subunits. The polyplacophoran hemocyanins are decamers with molecular weights of (4.2-4.6) X 10(6). The effectiveness of dissociation by the ureas follows the order of increasing hydrophobicity of the reagent, i.e., urea, methyl-, ethyl-, propyl- and butylurea, as expected of hydrophobically stabilized subunit systems. The urea dissociation is found to be a two-step reaction: the dissociation of parent decamers to dimers followed by dissociation of the dimers to monomers. Analysis of the observed decrease in molecular weight requires the interaction with urea of about 27 to 35 apparent amino-acid groups (Napp) at the contact areas of the dimers, and a much larger number of apparent binding groups ranging from about 100 to 120 per monomer at the contact areas of the monomers. Fitting of the pH dissociation profiles of A. granulata, C. stelleri, M. muscosa and S. conspicua requires the participation of a much smaller number of amino-acid residues in the interaction with the probe-solvent components. The ionization or protonation of one acidic and one basic group per dimer, and five to eight acidic and basic groups per monomer is found to be adequate for the description of the two-step pH dissociation reaction. PMID:3651468

  18. Proton angular distribution following multiphoton dissociative ionization of H2

    International Nuclear Information System (INIS)

    The angular distribution of protons ejected following resonant (2+1)-photon dissociative ionization of H2 by 193-nm radiation through the E,F state has been obtained. The analysis shows that the Π character of the degenerate continuum states is approximately eight times larger than the Σ character, which is consistent with previous single-photon measurements. The analysis presented here, together with a previous analysis of the proton energy distribution, reveals the ionization channel to be significantly stronger than both the dissociation and dissociative ionization channels

  19. The mediator roles of trait anxiety, hostility, and impulsivity in the association between childhood trauma and dissociation in male substance-dependent inpatients.

    Science.gov (United States)

    Evren, Cuneyt; Cınar, Ozgul; Evren, Bilge; Ulku, Muge; Karabulut, Vahap; Umut, Gokhan

    2013-02-01

    The aim of this study was to investigate the mediator roles of negative affect, aggression, and impulsivity in the association between childhood trauma and dissociation in male substance-dependent inpatients. In addition, the effect of some variables that may be related with childhood trauma and dissociation among treatment-seeking substance dependents, such as substance of choice (alcohol/drug), mean of current age, and age at regular substance use was controlled. Participants were consecutively admitted 200 male substance-dependent inpatients. Patients were investigated with the Dissociative Experiences Scale, the Childhood Trauma Questionnaire, the Barratt Impulsiveness Scale, the Buss-Perry Aggression Questionnaire, the Beck Depression Inventory, and the Spielberger State-Trait Anxiety Inventory. Seventy-seven patients (38.5%) with pathologic dissociation were compared with 123 nondissociative patients (61.5%) classified by dissociative taxon membership. The dissociative group had lower age, age at regular substance use, duration of education, and higher rate of drug dependency rather than alcohol dependency. Beside higher scores on anxiety, depression, childhood trauma, aggression, and impulsivity, a larger proportion of dissociative group reported suicide attempts and self-mutilation than did the nondissociative group. Results of regression analyses suggest that severity of chronic anxiety, aggression (particularly hostility), and impulsivity were found to be mediators of association between childhood trauma and dissociation. Results suggest that, to reduce the risk of dissociation and related behavior such as suicide attempt and self-mutilation among substance dependents, chronic anxiety together with the feelings of hostility and impulsivity must be the targets of evaluation and treatment among those with history of childhood trauma. PMID:22901836

  20. Experimental study on fly ash capture mercury in flue gas

    Institute of Scientific and Technical Information of China (English)

    Mercedes; DíAZ-SOMOANO; Patricia; ABAD-VALLE; M.Rosa; MARTíNEZ-TARAZONA

    2010-01-01

    Systematic experiments were conducted on a fixed-bed reactor to investigate the interaction between fly ash and mercury,the results implied that fly ash can capture mercury effectively.Among different fly ashes,the unburned carbon in the FA2 and FA3 fly ashes has the highest mercury capture capacity,up to 10.3 and 9.36 μg/g,respectively,which is close to that of commercial activated carbon.There is no obvious relationship between mercury content and carbon content or BET surface area of fly ash.Petrography classification standard was applied to distinguish fly ash carbon particles.Carbon content is not the only variable that controls mercury capture on fly ash,there are likely significant differences in the mercury capture capacities of the various carbon forms.Mercury capture capacity mainly depends on the content of anisotropy carbon particles with porous network structure.

  1. Analysis of ballistic capture in Sun-planet models

    Science.gov (United States)

    Luo, Z.-F.; Topputo, F.

    2015-09-01

    Analysis of ballistic capture orbits in Sun-planet systems is conducted in this paper. This mechanism utilizes purely gravitational forces, and may occur in non-Keplerian regimes. Ballistic capture orbits are generated by proper manipulation of sets of initial conditions that satisfy a simple definition of stability. Six Sun-planet systems are considered, including the inner planets, Jupiter, and Saturn. The role of planets orbital eccentricity, their true anomaly, and mass ratios is investigated. Moreover, the influence of the post-capture orbit in terms of inclination and orientation is also assessed. Analyses are performed from qualitative and quantitative perspective. The quality of capture orbits is measured by means of the stability index, whereas the capture ratio gives information on their statistical occurrence. Some underlying principles on the selection of the dynamical model, the initial true anomaly, and inclination are obtained. These provide a reference for practical cases.

  2. Electron capture by protons and deuterons

    International Nuclear Information System (INIS)

    Cross section measurements are reported for electron capture into the 3s state by 20-150 keV protons and deuterons incident on molecular hydrogen and deuterium. Conventional wisdom indicates that these cross sections should be nearly identical at equivalent velocities and researchers routinely use deuteron projectiles to extend proton excitation curves downward in velocity. This practice has been questioned on theoretical grounds and some investigators have reported consistent differences in cross sections for the two isotopes, however, nearly always within the experimental uncertainty of the measurements. The authors have made a systematic study of the 3s electron capture cross sections described above to check for isotopic effects. These cross sections are then compared to previous measurements reported in the literature

  3. Direct dissociative chemisorption of alkanes on Pt(111): Influence of molecular complexity

    International Nuclear Information System (INIS)

    The direct dissociative chemisorption of ethane, propane, n-butane, isobutane, and neopentane on Pt(111) was investigated as a function of the initial translational energy, ET, polar angle of incidence, θi, initial vibrational temperature, and surface temperature using supersonic molecular beam techniques. For each alkane, the initial probability for direct dissociative chemisorption scales with the initial normal energy of the alkanes, En=ET cos2 θi, and is independent of both the surface temperature and initial vibrational energy of the alkanes under the experimental conditions employed. Above initial normal energies of approximately 125 kJ/mol, at constant En, the dissociation probability decreases with increasing chain length of the C2-C4 linear alkanes; however, the dissociation probability of neopentane is greater than that of isobutane, and both isobutane and neopentane are more reactive than n-butane. By assuming that cleavage of primary C-H bonds is the dominant reaction pathway for all of the alkanes investigated here, the trends in reactivity are best explained by considering the differences in the steric factors for primary C-H bond cleavage for these alkanes. Secondary C-H bond cleavage does appear to contribute to the reactivity of propane and n-butane but only at the highest energies examined. Additionally, the reaction probabilities of each of these alkanes were estimated using a statistical model recently proposed by Ukrainstev and Harrison [J. Chem. Phys. 101, 1564 (1994)]. Assuming cleavage of only primary C-H bonds, the trends in reactivity for ethane, propane, n-butane, and isobutane were qualitatively reproduced by the statistical model; however, except for ethane, which was used to obtain the necessary parameters for the theory, there was poor quantitative agreement, and the predictions for neopentane were significantly lower than the measured values. The model also predicts that the dissociation probability is enhanced by increasing the

  4. On the dissociative electron attachment as a potential source of molecular hydrogen in irradiated liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Cobut, V.; Jay-Gerin, J.-P.; Frongillo, Y. [Sherbrooke Univ., PQ (Canada). Faculte de Medecine; Patau, J.P. [Toulouse-3 Univ., 31 (France)

    1996-02-01

    In the radiolysis of liquid water, different mechanisms for the formation of molecular hydrogen (H{sub 2}) are involved at different times after the initial energy disposition. It has been suggested that the contributions of the e{sub aq}{sup -} + e{sub aq}{sup -}, H + e{sub aq}{sup -} and H + H reactions between hydrated electrons (e{sub aq}{sup -}) and hydrogen atoms in the spurs are not sufficient to account for all of the observed H{sub 2} yield (0.45 molecules/100 eV) on the microsecond time scale. Addressing the question of the origin of an unscavengeable H{sub 2} yield of 0.15 molecules/100 eV produced before spur expansion, we suggest that the dissociative capture of the so-called vibrationally-relaxing electrons by H{sub 2}O molecules is a possible pathway for the formation of part of the initial H{sub 2} yield. Comparison of recent dissociative-electron-attachment H{sup -}-anion yield-distribution measurements from amorphous H{sub 2}O films with the energy spectrum of vibrationally-relaxing electrons in irradiated liquid water, calculated by Monte Carlo simulations, plays in favor of this hypothesis. (author).

  5. Heterolytic and Homolytic N-NO Bond Dissociation Energies of N-Nitroso-benzenesulfonylmethylamines in Acetonitrile

    Institute of Scientific and Technical Information of China (English)

    HAO Wei-Fang; Tang Hui; ZHU Xiao-Qing; CHENG Jin-Pei

    2003-01-01

    @@ Great interests have been accumulated in recent years in the chemistry and biochemistry of nitric oxide (NO) since the remarkable discoveries of its key roles in a wide range of human physiological processes. To elucidate the mechanistic details of NO migration from its donor to its acceptor, it is necessary to determine the Y-NO bind energy that registers the thermodynamic driving force for NO release and capture. In this paper the heterolytic and homolytic N-NO bond dissociation energies [ i. e., △Hhet(N-NO) and △Hhomo(N-NO)] for ten N-nitroso-p-substituted-benzensulfonyl methylamines in acetonitrile are offered, which were obtained from titration calorimetry and thermodynamic cycles, respectively (Scheme 1).

  6. Capture reactions at low energies

    International Nuclear Information System (INIS)

    Some few body capture reaction studies at low energies are reviewed. The emphasis is on the use of polarized beams. New calculations of n+d and p+d capture had just recently been completed by the Los Alamos group (Friar, Gibson, and Payne). Their results are in good agreement with existing data, and emphasize the importance of meson exchange current effects in these processes at thermal energies. The effects of M1 radiation can be seen in the vector analyzing power of the p+d radiative capture reaction from its interference with E1 radiation. The vector analyzing powers of the rvec p+T → 4He + γ reaction can be used to search for M1 radiation in 4He. Low energy data show a substantial b1 coefficient which can only be accounted for with a substantial M1 contribution. The author is also working on studying the rvec d+T and rvec d+3He capture reactions in the region of the fusion resonance. His (published) rvec d+T capture data indicate that the reaction goes via ∼95% S = 3/2, E1 capture with small S = 1/2, E1 and small M1 admixtures. In the course of obtaining the d+T and d+3He data, he realized that he could use his spectra to obtain the ground state widths of 5He and 5Li. Finally, he will discuss the d+d reaction at very low energies. The simplest picture of this reaction dominated by S wave capture to the D-state below 1 MeV

  7. Communication: Enhanced dissociative chemisorption of CO2 via vibrational excitation

    Science.gov (United States)

    Jiang, Bin; Guo, Hua

    2016-03-01

    A fully coupled global nine-dimensional potential energy surface for the dissociative chemisorption of CO2 on Ni(100) is constructed from ˜18 000 density functional points. It reveals a complex reaction pathway dominated by two near iso-energetic transition states. The dissociation probabilities obtained by quasi-classical trajectories on the potential energy surface reproduced experimental trends, and indicate that vibrational excitations of CO2 significantly promote the dissociation. Using the sudden vector projection model, the behavior of the reactivity is rationalized by couplings with the reaction coordinate at each transition state. These results offer plausible rationalization for the observed enhancement of CO2 dissociation in non-thermal plasmas by metal surfaces.

  8. Negligible Isotopic Effect on Dissociation of Hydrogen Bonds.

    Science.gov (United States)

    Ge, Chuanqi; Shen, Yuneng; Deng, Gang-Hua; Tian, Yuhuan; Yu, Dongqi; Yang, Xueming; Yuan, Kaijun; Zheng, Junrong

    2016-03-31

    Isotopic effects on the formation and dissociation kinetics of hydrogen bonds are studied in real time with ultrafast chemical exchange spectroscopy. The dissociation time of hydrogen bond between phenol-OH and p-xylene (or mesitylene) is found to be identical to that between phenol-OD and p-xylene (or mesitylene) in the same solvents. The experimental results demonstrate that the isotope substitution (D for H) has negligible effects on the hydrogen bond kinetics. DFT calculations show that the isotope substitution does not significantly change the frequencies of vibrational modes that may be along the hydrogen bond formation and dissociation coordinate. The zero point energy differences of these modes between hydrogen bonds with OH and OD are too small to affect the activation energy of the hydrogen bond dissociation in a detectible way at room temperature. PMID:26967376

  9. The Reaction of Dissociative Recombination in a Strong Light Field

    International Nuclear Information System (INIS)

    The DR theory of slow electrons with molecular ions in strong monochromatic light field is developed. The potential energy curves of the oxygen molecule O2** dissociative states are calculated. Classification of all possible transitions and reaction mechanisms are presented.

  10. Characterization and Modeling of the Collision Induced Dissociation Patterns of Deprotonated Glycosphingolipids: Cleavage of the Glycosidic Bond

    Science.gov (United States)

    Rožman, Marko

    2016-01-01

    Glycosphingolipid fragmentation behavior was investigated by combining results from analysis of a series of negative ion tandem mass spectra and molecular modeling. Fragmentation patterns extracted from 75 tandem mass spectra of mainly acidic glycosphingolipid species (gangliosides) suggest prominent cleavage of the glycosidic bonds with retention of the glycosidic oxygen atom by the species formed from the reducing end (B and Y ion formation). Dominant product ions arise from dissociation of sialic acids glycosidic bonds whereas product ions resulting from cleavage of other glycosidic bonds are less abundant. Potential energy surfaces and unimolecular reaction rates of several low-energy fragmentation pathways leading to cleavage of glycosidic bonds were estimated in order to explain observed dissociation patterns. Glycosidic bond cleavage in both neutral (unsubstituted glycosyl group) and acidic glycosphingolipids was the outcome of the charge-directed intramolecular nucleophilic substitution (SN2) mechanism. According to the suggested mechanism, the nucleophile in a form of carboxylate or oxyanion attacks the carbon at position one of the sugar ring, simultaneously breaking the glycosidic bond and yielding an epoxide. For gangliosides, unimolecular reaction rates suggest that dominant product ions related to the cleavage of sialic acid glycosidic bonds are formed via direct dissociation channels. On the other hand, low abundant product ions related to the dissociation of other glycosidic bonds are more likely to be the result of sequential dissociation. Although results from this study mainly contribute to the understanding of glycosphingolipid fragmentation chemistry, some mechanistic findings regarding cleavage of the glycosidic bond may be applicable to other glycoconjugates.

  11. The elastic properties, generalized stacking fault energy and dissociated dislocations in MgB2 under different pressure

    KAUST Repository

    Feng, Huifang

    2013-05-31

    The 〈112̄0〉 perfect dislocation in MgB2 is suggested to dissociate into two partial dislocations in an energy favorable way 〈112̄0〉 → 1/2 〈112̄0〉 + SF + 1/2 〈112̄0〉. This dissociation style is a correction of the previous dissociation 〈1000〉 → 1/3 〈11̄00〉 SF + 1/3 〈 2100〉proposed by Zhu et al. to model the partial dislocations and stacking fault observed by transmission electron microscopy. The latter dissociation results in a maximal stacking fault energy rather than a minimal one according to the generalized stacking fault energy calculated from first-principles methods. Furthermore, the elastic constants and anisotropy of MgB2 under different pressure are investigated. The core structures and mobilities of the 〈112̄0〉 dissociated dislocations are studied within the modified Peierls-Nabarro (P-N) dislocation theory. The variational method is used to solve the modified P-N dislocation equation and the Peierls stress is also determined under different pressure. High pressure effects on elastic anisotropy, core structure and Peierls stress are also presented. © 2013 Springer Science+Business Media New York.

  12. Differences in trauma history and psychopathology between PTSD patients with and without co-occurring dissociative disorders

    Directory of Open Access Journals (Sweden)

    Pascal Wabnitz

    2013-11-01

    Full Text Available Background: The interplay between different types of potentially traumatizing events, posttraumatic symptoms, and the pathogenesis of PTSD or major dissociative disorders (DD has been extensively studied during the last decade. However, the phenomenology and nosological classification of posttraumatic disorders is currently under debate. The current study was conducted to investigate differences between PTSD patients with and without co-occurring major DD with regard to general psychopathology, trauma history, and trauma-specific symptoms. Methods: Twenty-four inpatients were administered the Clinician-Administered PTSD Scale for DSM-IV (CAPS and the Mini-Structured Clinical Interview for DSM-IV Dissociative Disorders (MINI-SKID-D to assess DD and PTSD. Additionally, participants completed questionnaires to assess general psychopathology and health status. Results: Symptom profiles and axis I comorbidity were similar in all patients. Traumatic experiences did not differ between the two groups, with both reporting high levels of childhood trauma. Only trauma-specific avoidance behavior and dissociative symptoms differed between groups. Conclusion: Results support the view that PTSD and DD are affiliated disorders that could be classified within the same diagnostic category. Our results accord with a typological model of dissociation in which profound forms of dissociation are specific to DD and are accompanied with higher levels of trauma-specific avoidance in DD patients.

  13. Bioaccumulation of dissociating substances; Bioakkumulation dissoziierender Stoffe

    Energy Technology Data Exchange (ETDEWEB)

    Butte, W.; Plegge, V.; Schettgen, C.; Willenborg, R.; Zauke, G.P. [Oldenburg Univ. (Germany). Fachbereich Chemie; Kuhlmann, H. [Oldenburg Univ. (Germany). Fachbereich Chemie]|[Bundesforschungsanstalt fuer Fischerei, Ahrensburg (Germany). Inst. fuer Fischereioekologie

    2000-02-01

    Bioconcentration factors (BCF) are important parameters to assess the environmental fate of chemicals. In this report we describe the determination of BCF for Triclosan, a trichlorophenoxy phenol, for some dissociating herbicides like Dichlorprop, MCPA, Mecoprop, Triclopyr and Picloram as well as for selected pyrethroids like Cyfluthrin, Cypermethrin, Deltamethrin and Permethrin. It was shown that BCF and rate constants for the uptake of Triclosan are decreasing with an increasing pH of the test water. The BCF for the herbicides evaluated are all below 10, confirming data already reported for herbicides of similar structure. Thus, for these compounds there is no tendency to bioaccumulate. Furthermore, there was no correlation between BCF and n-octanol/water partition coefficients or dissociation constants. BCF of pyrethroids were between 860 and 2200. For the analysis of pyrenthroid metabolites a gas chromatographic method using daughter-ion mass spectrometry for detection was established. The detection limit of this method was 1 {mu}g/kg, but metabolites could not be detected in fish during the bioaccumulation experiments. The high toxicity of pyrethroids for fish was approved; LC50-values were between 1 and 5 {mu}g/l. To evaluate physiological effects in fish, produced by pyrethroids, EROD activities in preparations of trout liver were measured. No increase in activity could be detected, but there was a tendency to lower values. We think this to result from the high toxicity of pyrethroids that could have impaired this enzyme system. (orig.) [German] Biokonzentrationsfaktoren (BCF) sind wichtige Parameter, mit Hilfe derer das Umweltverhalten von Chemikalien abgeschaetzt werden kann. Im Rahmen dieses Forschungsvorhabens wurden BCF-Werte fuer Triclosan, ein Trichlorphenoxyphenol, fuer einige dissoziierende Herbizide: Dichlorprop, MCPA, Mecoprop, Triclopyr und Picloram sowie fuer ausgewaehlte Pyrethroide: Cyfluthrin, Cypermethrin, Deltamethrin und Permethrin

  14. Structural analysis of ruthenium–arene complexes using ion mobility mass spectrometry, collision-induced dissociation, and DFT

    OpenAIRE

    Cserwinska, Izabella; Far, Johann; Kune, Christopher; Larriba-Andaluz, Carlos; Delaude, Lionel; De Pauw, Edwin

    2016-01-01

    Ion mobility mass spectrometry (IM-MS) and collision-induced dissociation (CID) techniques were used to investigate the influence of the phosphine ligand on the physicochemical properties of [RuCl2(p-cymene)(PCy3)] (1), [RuCl2(p-cymene)-(PPh3)] (2), and [RuCl2(p-cymene)(PTA)] (3) in the gas phase (PTA is 1,3,5-triaza-7-phosphaadamantane). Electrospray ionization of complexes 1 and 2 led to the corresponding [RuCl(p-cymene)(PR3)]+ ions via the dissociation of a chlorido ligand, whereas RAPTA-C...

  15. Dissociable Learning Processes Underlie Human Pain Conditioning.

    Science.gov (United States)

    Zhang, Suyi; Mano, Hiroaki; Ganesh, Gowrishankar; Robbins, Trevor; Seymour, Ben

    2016-01-11

    Pavlovian conditioning underlies many aspects of pain behavior, including fear and threat detection [1], escape and avoidance learning [2], and endogenous analgesia [3]. Although a central role for the amygdala is well established [4], both human and animal studies implicate other brain regions in learning, notably ventral striatum and cerebellum [5]. It remains unclear whether these regions make different contributions to a single aversive learning process or represent independent learning mechanisms that interact to generate the expression of pain-related behavior. We designed a human parallel aversive conditioning paradigm in which different Pavlovian visual cues probabilistically predicted thermal pain primarily to either the left or right arm and studied the acquisition of conditioned Pavlovian responses using combined physiological recordings and fMRI. Using computational modeling based on reinforcement learning theory, we found that conditioning involves two distinct types of learning process. First, a non-specific "preparatory" system learns aversive facial expressions and autonomic responses such as skin conductance. The associated learning signals-the learned associability and prediction error-were correlated with fMRI brain responses in amygdala-striatal regions, corresponding to the classic aversive (fear) learning circuit. Second, a specific lateralized system learns "consummatory" limb-withdrawal responses, detectable with electromyography of the arm to which pain is predicted. Its related learned associability was correlated with responses in ipsilateral cerebellar cortex, suggesting a novel computational role for the cerebellum in pain. In conclusion, our results show that the overall phenotype of conditioned pain behavior depends on two dissociable reinforcement learning circuits. PMID:26711494

  16. Subacute transverse myelitis with Lyme profile dissociation

    Directory of Open Access Journals (Sweden)

    Ajjan, Mohammed

    2008-06-01

    Full Text Available Introduction: Transverse myelitis is a very rare neurologic syndrome with an incidence per year of 1-5 per million population. We are presenting an interesting case of subacute transverse myelitis with its MRI (magnetic resonance imaging and CSF (cerebrospinal fluid findings. Case: A 46-year-old African-American woman presented with decreased sensation in the lower extremities which started three weeks ago when she had a 36-hour episode of sore throat. She reported numbness up to the level just below the breasts. Lyme disease antibodies total IgG (immunoglobulin G and IgM (immunoglobulin M in the blood was positive. Antinuclear antibody profile was within normal limits. MRI of the cervical spine showed swelling in the lower cervical cord with contrast enhancement. Cerebrospinal fluid was clear with negative Borrelia Burgdorferi IgG and IgM. Herpes simplex, mycoplasma, coxiella, anaplasma, cryptococcus and hepatitis B were all negative. No oligoclonal bands were detected. Quick improvement ensued after she was given IV Ceftriaxone for 7 days. The patient was discharged on the 8th day in stable condition. She continued on doxycycline for 21 days. Conclusions: Transverse myelitis should be included in the differential diagnosis of any patient presenting with acute or subacute myelopathy in association with localized contrast enhancement in the spinal cord especially if flu-like prodromal symptoms were reported. Lyme disease serology is indicated in patients with neurological symptoms keeping in mind that dissociation in Lyme antibody titers between the blood and the CSF is possible.

  17. Electromagnetic Dissociation and Spacecraft Electronics Damage

    Science.gov (United States)

    Norbury, John W.

    2016-01-01

    When protons or heavy ions from galactic cosmic rays (GCR) or solar particle events (SPE) interact with target nuclei in spacecraft, there can be two different types of interactions. The more familiar strong nuclear interaction often dominates and is responsible for nuclear fragmentation in either the GCR or SPE projectile nucleus or the spacecraft target nucleus. (Of course, the proton does not break up, except possibly to produce pions or other hadrons.) The less familiar, second type of interaction is due to the very strong electromagnetic fields that exist when two charged nuclei pass very close to each other. This process is called electromagnetic dissociation (EMD) and primarily results in the emission of neutrons, protons and light ions (isotopes of hydrogen and helium). The cross section for particle production is approximately defined as the number of particles produced in nucleus-nucleus collisions or other types of reactions. (There are various kinematic and other factors which multiply the particle number to arrive at the cross section.) Strong, nuclear interactions usually dominate the nuclear reactions of most interest that occur between GCR and target nuclei. However, for heavy nuclei (near Fe and beyond) at high energy the EMD cross section can be much larger than the strong nuclear interaction cross section. This paper poses a question: Are there projectile or target nuclei combinations in the interaction of GCR or SPE where the EMD reaction cross section plays a dominant role? If the answer is affirmative, then EMD mechanisms should be an integral part of codes that are used to predict damage to spacecraft electronics. The question can become more fine-tuned and one can ask about total reaction cross sections as compared to double differential cross sections. These issues will be addressed in the present paper.

  18. Dissociative Identity Disorders in Korea: Two Recent Cases

    OpenAIRE

    Kim, Ilbin; Kim, Daeho; Jung, Hyun-Jin

    2016-01-01

    Although dissociative identity disorder (DID), the most severe of the dissociative disorders, has retained its own diagnostic entity since its introduction in the DSM-III, cases of DID are rarely seen in South and East Asia, likely due to the higher prevalence of possession disorder. We report two patients with DID who were recently admitted to our inpatient psychiatric unit and demonstrated distinct transitions to several identities. Their diagnoses were confirmed through a structured interv...

  19. Childhood maltreatment and intimate partner violence in dissociative disorder patients

    OpenAIRE

    Webermann, Aliya R.; Brand, Bethany L.; Chasson, Gregory S.

    2014-01-01

    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. Ind...

  20. [Persistent Perpetrator Contact in a Patient with Dissociative Identity Disorder].

    Science.gov (United States)

    Tschöke, Stefan; Eisele, Frank; Steinert, Tilman

    2016-05-01

    The case of a young woman with still ongoing incest and forced prostitution is presented. The criteria for a dissociative identity disorder (DID) were met. Due to persistent contact to the perpetrator she was repeatedly revictimized. Based on the model of trauma-related dissociation we discuss to what extent she was capable of self-determined decision making as well as therapeutic consequences resulting therefrom. PMID:26556682