Triviality of the ground-state metastate in long-range Ising spin glasses in one dimension

We consider the one-dimensional model of a spin glass with independent Gaussian-distributed random interactions, that have mean zero and variance $1/|i-j|^{2\sigma}$, between the spins at sites $i$ and $j$ for all $i\neq j$. It is known that, for $\sigma>1$, there is no phase transition at any non-zero temperature in this model. We prove rigorously that, for $\sigma>3/2$, any Newman-Stein metastate for the ground states (i.e.\ the frequencies with which distinct ground states are observed in finite size samples in the limit of infinite size, for given disorder) is trivial and unique. In other words, for given disorder and asymptotically at large sizes, the same ground state, or its global spin flip, is obtained (almost) always. The proof consists of two parts: one is a theorem (based on one by Newman and Stein for short-range two-dimensional models), valid for all $\sigma>1$, that establishes triviality under a convergence hypothesis on something similar to the energies of domain walls, and the other (based on older results for the one-dimensional model) establishes that the hypothesis is true for $\sigma>3/2$. In addition, we derive heuristic scaling arguments and rigorous exponent inequalities which tend to support the validity of the hypothesis under broader conditions. The constructions of various metastates are extended to all values $\sigma>1/2$. Triviality of the metastate in bond-diluted power-law models for $\sigma>1$ is proved directly.Comment: 18 pages. v2: subsection on bond-diluted models added, few extra references. 19 pages. v3: published version; a few changes; 20 page

Gasphasen-Chemie negativer Ionen des Tris(trifluormethyl)phosphans und Charakterisierung einer zylindrischen offenen ICR-Zelle mit Elektroden unterschiedlichen Durchmessers

In a five sections cylindrical ion cyclotron resonance (ICR) cell the ion chemistry of tris(trifluoromethyl)phosphine has been investigated. The only major negative primary ion, produced by dissociative electron attachment is the phosphide ion (CF3)2P- , which reacts at elevated kinetic energy with the neutral molecules at 2x10-7 mbar to produce three phosphoranides: CF3PF3-, (CF3)2PF2-, and (CF3)3PF-. Simultaneously, three minor ions CF3-, F-, and C2F3- are formed by Self-Collision Induced Dissociation. Ion-molecule reactions between CF3- and the (CF3)3P has also been investigated. Positive ions form phosphonium ions and a diphosphonium product ion, (CF3)2P-P(CF3)3 , whereas no P-P bond is observed with negative ions. All the structures and reaction pathways have been investigated theoretically with the aid of DFT calculations. The results are in excellent agreement with the experiments.Several approaches have been implemented to study ion-ion interactions of singly charged positive and negative ions in a new open five sectional cylindrical ICR cell with an unusual geometry, capable to trap and detect both positive and negative ions in different axial regions simultaneously. Although single shot experiments, which were initially done in an attempt to achieve ion-ion interactions, did not lead to neutralisation of the reactant ions, therefore RF-pulse and pulse sequences with different shapes, frequencies and durations were implemented to establish longer axial overlaps between positive and negative ions in a shared central region. These RF-driven ion-ion spatial overlaps are discussed in detail in this article. Specific characteristic behaviours of the new ICR cell have been also studied.Single shot experiments were done in a new open cylindrical ICR cell to establish ion-ion collisions between positive and negative ions of SF6 in the gas phase for the first time. The role of pressure was illustrated to encourage high ion densities to be a prerequisite for ion-ion reactions. No electron transfer could be deduced from the experiments. Anion-Anion collisions could be indicated. The dynamics of applied potential changes on both ion polarities in a double well potential configuration were studied intensively. In depth analysis of radial excitation patterns of positive and negative ions trapped simultaneously in different stability regions reveals sharp discrimination in the extent of radial acceleration. SIMION simulations were done to probe several electric forces, which both positive and negative ions experience during radial excitation event. Axial component of radial dipolar excitation field was also analyzed. Distortion in radial ion trajectories during radial excitation event was indicated when both ion polarities were excited simultaneously

Gas Phase Chemistry of Negative Ions of Tris(trifluoromethyl)phosphine and Characterization of Cylindrical Open ICR-cell with Electrodes of Different Diameters.

In a five sections cylindrical ion cyclotron resonance (ICR) cell the ion chemistry of tris(trifluoromethyl)phosphine has been investigated. The only major negative primary ion, produced by dissociative electron attachment is the phosphide ion (CF3)2P- , which reacts at elevated kinetic energy with the neutral molecules at 2x10-7 mbar to produce three phosphoranides: CF3PF3-, (CF3)2PF2-, and (CF3)3PF-. Simultaneously, three minor ions CF3-, F-, and C2F3- are formed by Self-Collision Induced Dissociation. Ion-molecule reactions between CF3- and the (CF3)3P has also been investigated. Positive ions form phosphonium ions and a diphosphonium product ion, (CF3)2P-P(CF3)3 , whereas no P-P bond is observed with negative ions. All the structures and reaction pathways have been investigated theoretically with the aid of DFT calculations. The results are in excellent agreement with the experiments.Several approaches have been implemented to study ion-ion interactions of singly charged positive and negative ions in a new open five sectional cylindrical ICR cell with an unusual geometry, capable to trap and detect both positive and negative ions in different axial regions simultaneously. Although single shot experiments, which were initially done in an attempt to achieve ion-ion interactions, did not lead to neutralisation of the reactant ions, therefore RF-pulse and pulse sequences with different shapes, frequencies and durations were implemented to establish longer axial overlaps between positive and negative ions in a shared central region. These RF-driven ion-ion spatial overlaps are discussed in detail in this article. Specific characteristic behaviours of the new ICR cell have been also studied.Single shot experiments were done in a new open cylindrical ICR cell to establish ion-ion collisions between positive and negative ions of SF6 in the gas phase for the first time. The role of pressure was illustrated to encourage high ion densities to be a prerequisite for ion-ion reactions. No electron transfer could be deduced from the experiments. Anion-Anion collisions could be indicated. The dynamics of applied potential changes on both ion polarities in a double well potential configuration were studied intensively. In depth analysis of radial excitation patterns of positive and negative ions trapped simultaneously in different stability regions reveals sharp discrimination in the extent of radial acceleration. SIMION simulations were done to probe several electric forces, which both positive and negative ions experience during radial excitation event. Axial component of radial dipolar excitation field was also analyzed. Distortion in radial ion trajectories during radial excitation event was indicated when both ion polarities were excited simultaneously

Electrochemical triggering of the Chardonnay wine metabolome

International audienceOxidation of wine upon bottle ageing is a crucial matter of concern for the qualitative long-term storage of white wines. However, understanding the various molecular mechanisms potentially involved, which can impact the wine composition, requires that top-down analytical strategies are implemented. Here, we report the analysis of bottle aged Chardonnay wines made from the same must, but differing by the amount of SO2 initially added to the must at pressing (0 and 8 g.hL-1). Metabolomics fingerprints obtained from electrochemical simulation of oxidative reactions were obtained by the coupling of either on-line or off-line electrochemical oxidation to FT-ICR-MS detection. We reveal that, whatever the electrochemical DC voltage, wines with initial SO2 addition displayed molecular fingerprints, which remained more similar to the non-oxidized wine without initial SO2 addition. We further show that a diversity of sulfur-containing compounds appeared to be the most sensitive to oxidation, whereas nitrogen-containing compounds were mostly formed

Identification of two Arginine Kinase forms of endoparasitoid Leptomastix dactylopii venom by bottom up-sequence tag approach.

Leptomastix dactylopii (Howard) is an endoparasitoid wasp natural enemy of mealybug Planococcus citri (Risso). Despite the acquired knowledge regarding this host-parasitoid interaction, only little information are available on the factors of parasitoid origin able to modulate the mealybug physiology. The major alteration observed in P. citri is a strong reduction in fecundity, which is evident soon after parasitization by L. dactylopii or venom injection in unparasitized hosts indicating that this proteinaceus secretion injected at the oviposition plays a key-role in host regulation. Protein identification of L. dactilopii venom has been limited by the lack of literature sources and public protein databases. Here, we identified two venom proteins by an integrated trascriptomic and proteomic approach. A custom-made transcriptomic database from the L. dactylopii venom glands was created by applying the high-throughput RNA sequencing approach. Two-dimensional gel electrophoresis (2DE) trypsinised protein spots were analyzed by high-resolution mass spectrometry (FTICRMS-12T). The most abundant peptide ions were fragmented by collision induced dissociation and the obtained sequence tags were subjected to custom-made protein database searching. Two putative Arginine Kinases (full-length and truncated form) were identified. This is the first case in which both, truncated and full length Arginine Kinases, are identified in an endoparadsitoid non paralyzing veno

Attachment of chloride anion to sugars: mechanistic investigation and discovery of a new dopant for efficient sugar ionization/detection in mass spectrometers.

International audienceA new method for efficient ionization of sugars in the negative-ion mode of electrospray mass spectrometry is presented. Instead of using strongly hydrophobic dopants such as dichloromethane or chloroform, efficient ionization of sugars has been achieved by using aqueous HCl solution for the first time. This methodology makes it possible to use hydrophilic dopants, which are more appropriate for chromatographic separation techniques with efficient sugar ionization and detection in mass spectrometry. The interaction between chloride anions and monosaccharides (glucose and galactose) was studied by DFT in the gas phase and by implementing the polarizable continuum model (PCM) for calculations in solution at the high B3LYP/6-31+G(d,p)//B3LYP/6-311+G(2d,p) level of theory. In all optimized geometries of identified [M+Cl](-) anions, a non-covalent interaction exists. Differences were revealed between monodentate and bidentate complex anions, with the latter having noticeably higher binding energies. The calculated affinity of glucose and galactose toward the chloride anion in the gas phase and their chloride anion binding energies in solution are in excellent agreement with glucose and galactose [M+Cl](-) experimental intensity profiles that are represented as a function of the chloride ion concentration. Density functional calculations of gas-phase affinities toward chloride anion were also performed for the studied disaccharides sucrose and gentiobiose. All calculations are in excellent agreement with the experimental data. An example is introduced wherein HCl was used to effectively ionize sugars and form chlorinated adduct anions to detect sugars and glycosylated metabolites (anthocyanins) in real biological systems (Vitis vinifera grape extracts and wines), whereas they would not have been easily detectable under standard infusion electrospray mass spectrometry conditions as deprotonated species

Automated microextraction sample preparation coupled on-line to FT-ICR-MS: Application to desalting and concentration of river and marine dissolved organic matter

Sample preparation procedures are in most cases sample- and time-consuming and commonly require the use of a large amount of solvents. Automation in this regard can optimize the minimal-needed injection volume and the solvent consumption will be efficiently reduced. A new fully automated sample desalting and pre-concentration technique employing microextraction by packed sorbents (MEPS) cartridges is implemented and coupled to an ion cyclotron resonance Fourier-transform mass spectrometer (ICR-FT/MS). The performance of non-target mass spectrometric analysis is compared for the automated versus off-line sample preparation for several samples of aqueous natural organic matter. This approach can be generalized for any metabolite profiling or metabolome analysis of biological materials but was optimized herein using a well characterized but highly complex organic mixture: a surface water and its well-characterized natural organic matter and a marine sample having a highly salt charge and enabling to validate the presented automatic system for salty samples. The analysis of Suwannee River water showed selective C18-MEPS enrichment of chemical signatures with average H/C and O/C elemental ratios and loss of both highly polar and highly aromatic structures from the original sample. Automated on-line application to marine samples showed desalting and different chemical signatures from surface to bottom water. Relative comparison of structural footprints with the C18-concentration/desalting procedure however enabled to demonstrate that the surface water film was more concentrated in surface-active components of natural (fatty acids) and anthropogenic origin (sulfur-containing surfactants). Overall, the relative standard deviation distribution in terms of peak intensity was improved by automating the proposed on-line method. © 2009 Springer-Verlag.G. Morales-Cid wishes to thank the Spain’s Ministry of Innovation and Science for the award of a FPI fellowship (Grant BES-2005-10603) to work with the German colleagues and the additional economic support within the mobility programPeer Reviewe

Usage of FT-ICR-MS Metabolomics for Characterizing the Chemical Signatures of Barrel-Aged Whisky

International audienceWhisky can be described as a complex matrix integrating the chemical history from the fermented cereals, the wooden barrels, the specific distillery processes, aging, and environmental factors. In this study, using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), we analyzed 150 whisky samples from 49 different distilleries, 7 countries, and ranging from 1 day new make spirit to 43 years of maturation with different types of barrel. Chemometrics revealed the unexpected impact of the wood history on the distillate's composition during barrel aging, regardless of the whisky origin. Flavonols, oligolignols, and fatty acids are examples of important chemical signatures for Bourbon casks, whereas a high number of polyphenol glycosides, including for instance quercetin-glucuronide or myricetin-glucoside as potential candidates, and carbohydrates would discriminate Sherry casks. However, the comparison of barrel aged rums and whiskies revealed specific signatures, highlighting the importance of the initial composition of the distillate and the distillery processes