Orbital Trap Research Articles

Study of Nettle (Urtica dióica) Lignin by Atmospheric Pressure Photoionization Orbitrap Mass Spectrometry

Orbital ion trap high-resolution mass spectrometry with acetone doped atmospheric pressure photoionization is first used to characterize the structure of grass lignins using an example of nettle (Urtica dioica) dioxane lignin. The obtained mass spectrum contains about 3,000 peaks of deprotonated molecules of lignin oligomers in the molecular mass range up to 1.6 kDa. The study of tandem mass spectra and of a composition of monomers formed in the collision-induced dissociation of lignin macromolecules showed the special role of p-hydroxycinnamic acids in the formation of nettle lignin. Based on the results of tandem mass spectrometry, possible structures of nettle lignin oligomers formed by the addition of guaiacyl- and syringylpropane units followed by etherification by p-coumaric, ferulic, and dihydroferulic acids are proposed.

Structural characterization of the ligstroside aglycone isoforms in virgin olive oils by liquid chromatography-high-resolution Fourier-transform mass spectrometry and H/Dexchange.

A systematic structural characterization of the isomeric forms related to ligstroside aglycone (LA), one of the most relevant secoiridoids contained in virgin olive oils, was performed using reverse phase liquid chromatography with electrospray ionization Fourier-transform single and tandem mass spectrometry, operated in negative ion mode (RPLC-ESI(-)-FTMS and FTMS/MS). The high mass resolution and accuracy provided by the adopted orbital trap mass analyzer enabled the recognition of more than 10 different isomeric forms of LA in virgin olive oil extracts. They were related to four different types of molecular structure, two of which including a dihydropyranic ring bearing one or two aldehydic groups, whereas the others corresponded to dialdehydic open-structure forms, differing just for the position of a C═C bond. The contemporary presence of enolic or dienolic tautomers associated to most of these compounds, stable at room temperature (23°C), was also assessed through RPLC-ESI-FTMS analyses operated under H/D exchange conditions, ie, by using D2 O instead of H2 O as co-solvent of acetonitrile in the RPLC mobile phase. As discussed in the paper, the results obtained for LA indicated a remarkable structural similarity with oleuropein aglycone (OA), the most abundant secoiridoid of olive oil, whose isoforms had been previously characterized using the same analytical approach.

Single Cell Analysis by High-Resolution Atmospheric-Pressure MALDI MS Imaging.

Complementary to other imaging techniques, MALDI MS imaging provides label-free analysis and chemical specificity, covering a wide range of molecules that can be visualized simultaneously. Here, we highlight a protocol to visualize lipids from single cardiac cells using high-resolution atmospheric-pressure matrix-assisted laser desorption/ionization coupled to an orbital trapping mass analyzer.

Visualizing and Profiling Lipids in the OVLT of Fat-1 and Wild Type Mouse Brains during LPS-Induced Systemic Inflammation Using AP-SMALDI MSI.

Lipids, including omega-3 polyunsaturated fatty acids (n-3-PUFAs), modulate brain-intrinsic inflammation during systemic inflammation. The vascular organ of the lamina terminalis (OVLT) is a brain structure important for immune-to-brain communication. We, therefore, aimed to profile the distribution of several lipids (e.g., phosphatidyl-choline/ethanolamine, PC/PE), including n-3-PUFA-carrying lipids (esterified in phospholipids), in the OVLT during systemic lipopolysaccharide(LPS)-induced inflammation. We injected wild type and endogenously n-3-PUFA producing fat-1 transgenic mice with LPS (i.p., 2.5 mg/kg) or PBS. Brain samples were analyzed using immunohistochemistry and high-resolution atmospheric-pressure scanning microprobe matrix-assisted laser desorption/ionization orbital trapping mass spectrometry imaging (AP-SMALDI-MSI) for spatial resolution of lipids. Depending on genotype and treatment, several distinct distribution patterns were observed for lipids [e.g., lyso(L)PC (16:0)/(18:0)] proposed to be involved in inflammation. The distribution patterns ranged from being homogeneously disseminated [LPC (18:1)], absent/reduced signaling within the OVLT relative to adjacent preoptic tissue [PE (38:6)], either treatment- and genotype-dependent or independent low signal intensities [LPC (18:0)], treatment- and genotype-dependent [PC 38:6)] or independent accumulation in the OVLT [PC (38:7)], and accumulation in commissures, e.g., nerve fibers like the optic nerve [LPE (18:1)]. Overall, screening of lipid distribution patterns revealed distinct inflammation-induced changes in the OVLT, highlighting the prominent role of lipid metabolism in brain inflammation. Moreover, known and novel candidates for brain inflammation and immune-to-brain communication were detected specifically within this pivotal brain structure, a window between the periphery and the brain. The biological significance of these newly identified lipids abundant in the OVLT and the adjacent preoptic area remains to be further analyzed.

Dark matter bars in spinning haloes

ABSTRACT We study non-linear response of spinning dark matter (DM) haloes to dynamic and secular evolution of stellar bars in the embedded galactic discs, using high-resolution numerical simulations. For a sequence of haloes with the cosmological spin parameter λ = 0–0.09, and a representative angular momentum distribution, we analyse evolution of induced DM bars amplitude and quantify parameters of the response as well as trapping of DM orbits and angular momentum transfer by the main and secondary resonances. We find that (1) maximal amplitude of DM bars depends strongly on λ, while that of the stellar bars is indifferent to λ; (2) efficiency of resonance trapping of DM orbits by the bar increases with λ, and so is the mass and the volume of DM bars; (3) contribution of resonance transfer of angular momentum to the DM halo increases with λ, and for larger spin, the DM halo ‘talks’ to itself, by moving the angular momentum to larger radii – this process is maintained by resonances; and (4) prograde and retrograde DM orbits play different roles in angular momentum transfer. The ‘active’ part of the halo extends well beyond the bar region, up to few times the bar length in equatorial plane and away from this plane. (5) We model evolution of discless DM haloes and haloes with frozen discs, and found them to be perfectly stable to any Fourier modes. Finally, further studies adopting a range of mass and specific angular momentum distributions of the DM halo will generalize the dependence of DM response on the halo spin and important implications for direct detection of DM and that of the associated stellar tracers, such as streamers.

On the ridges, undulations & streams in Gaia DR2: Linking the topography of phase-space to the orbital structure of an N-body bar

Abstract We explore the origin of phase-space substructures revealed by the second Gaia data release in the disc of the Milky Way, such as the ridges in the Vφ-r plane, the undulations in the Vφ-r-Vr space and the streams in the Vφ-Vr plane. We use a collisionless N-body simulation with co-spatial thin and thick discs, along with orbit integration, to study the orbital structure close to the Outer Lindblad Resonance (OLR) of the bar. We find that a prominent, long-lived ridge is formed in the Vφ-r plane due to the OLR which translates to streams in the Vφ-Vr plane and examine which closed periodic and trapped librating orbits are responsible for these features. We find that orbits which carry out small librations around the x1(1) family are preferentially found at negative Vr, giving rise to a ‘horn’-like feature, while orbits with larger libration amplitudes, trapped around the x1(2) and x1(1) families, constitute the positive Vr substructure, i.e. the Hercules-like feature. This changing libration amplitude of orbits will translate to a changing ratio of thin/thick disc stars, which could have implications on the metallicity distribution in this plane. We find that a scenario in which the Sun is placed close to the OLR gives rise to a strong asymmetry in Vr in the Vφ-Vr plane (i.e. Hercules vs. ‘the horn’) and subsequently to undulations in the Vφ-r-Vr space. We also explore a scenario in which the Sun is placed closer to the bar corotation and find that the bar perturbation alone cannot give rise to the these features.

Comparison of sample preparation approaches and validation of an extraction method for nitrosatable pesticides and metabolites in human serum and urine analyzed by liquid chromatography – Orbital ion trap mass spectrometry

In the acidic environment of the stomach, nitrosatable pesticide residues may react with nitrite to form potentially carcinogenic pesticide-associated N-nitroso compounds (PANOCs). The objective of this study was to develop a method for the analysis of 10 nitrosatable pesticides and breakdown products in human serum and urine. Three sample preparation methods were evaluated for extraction of target analytes from the biomatrices. Deproteinization by methanol for 300-μL aliquots of serum with a final extract volume of 225 μL resulted in excessive ion enhancement of some analytes and suppression of others. Three types of solid-phase extraction cartridges were tested for optimal analyte retention from 200-μL aliquots of serum with a final extract volume of 400 μL; this approach resulted in significant analyte loss for some compounds. The Quick, Easy, Cheap, Effective, Rugged, and Safe approach resulted in a suitable method for extraction of the analytes from each biomatrix. Biofluid samples (500 μL) were spiked to 100 μg L−1 with analytical standards and extracted using 500 μL of acetonitrile (ACN) with 4% acetic acid (AcOH) for serum and 0.1% AcOH in ACN for urine. For extraction, 200 mg magnesium sulfate (MgSO4) and 50 mg sodium acetate were added for serum and 200 mg MgSO4 and 50 mg sodium chloride were added for urine. Final extract volumes for both biomatrices using the QuEChERS method was 400 μL after dilution. Samples were analyzed via ultra-high pressure liquid chromatography/high-resolution accurate mass orbital ion trap mass spectrometry. Mean recoveries for target analytes in serum and urine ranged between 74 and 120% (%RSD < 12) and 96 to 116% (%RSD ≤ 10), respectively. These methods may be used in large-scale biomonitoring studies to analyze PANNs and their parent compounds in human serum and urine.

The puzzle of unbarred galaxies

AbstractNearly two thirds of spiral galaxies are either strongly or weakly barred, yet a significant fraction of disc galaxies do not have a bar. Now we understand that there are at least three ways of making bars, i.e., bar instability, tidal interaction, and secular bar growth by orbit trapping of a seed bar. However, the reverse problem of avoiding bar formation in unbarred galaxies may be more challenging than we thought. It is shocking that we still do not understand how the bar instability is avoided in real galaxies such as M33, and this puzzle may be central to the outstanding issue of what determines the distribution of bar strengths in galaxies.

Normal and Anomalous Diffusion in Soft Lorentz Gases.

Motivated by electronic transport in graphenelike structures, we study the diffusion of a classical point particle in Fermi potentials situated on a triangular lattice. We call this system a soft Lorentz gas, as the hard disks in the conventional periodic Lorentz gas are replaced by soft repulsive scatterers. A thorough computational analysis yields both normal and anomalous (super)diffusion with an extreme sensitivity on model parameters. This is due to an intricate interplay between trapped and ballistic periodic orbits, whose existence is characterized by tonguelike structures in parameter space. These results hold even for small softness, showing that diffusion in the paradigmatic hard Lorentz gas is not robust for realistic potentials, where we find an entirely different type of diffusion.

Identification and Determination of Rubrofusarin, Rubrofusarin Isomer, and Their Quinone Forms in Grains Using High-Resolution Mass Spectrometry.

Fungi of the genus Fusarium can produce secondary metabolites such as naphthopyrones and naphthoquinones that are toxic and expected to threaten the food and feed safety. In this study, the occurrence of rubrofusarin, rubrofusarin isomer, and their quinone forms in grains was identified and confirmed using ultrahigh-performance liquid chromatography coupled with hybrid quadrupole orbital ion trap mass spectrometry (Q-Orbitrap MS). The quantitation of these compounds in grain samples was also investigated using Q-Orbitrap MS. The results showed the concentrations of rubrofusarin ranged from 3.278 to 33.82 μg/kg, from 0.815 to 61.86 μg/kg, and from 7.362 to 47.24 μg/kg for the maize, rice, and wheat samples, respectively. By comparison, the abundances of their quinone forms were relatively lower, and the concentration of quinone form of rubrofusarin isomer was relatively higher than that of quinone form of rubrofusarin. These compounds were also confirmed to coexist with other known Fusarium mycotoxins. The data-dependent tandem mass spectra obtained from the Q-Orbitrap MS were validated to provide a wealth of valuable information that allowed for advanced data interpretation for solid confirmation of these compounds in grains. To the best of our knowledge, this is the first study that concerns the occurrence and quantitation of rubrofusarin, rubrofusarin isomer, and their quinone forms in grains.

Abstract 487: MicroRNA regulation of oral squamous cell carcinoma

Abstract Oral squamous cell carcinoma (OSCC) remains the sixth most common human cancer with high mortality rate worldwide. Understanding the molecular mechanisms is important for development of an effective treatment for the disease. MicroRNA is a short, noncoded nucleotide playing an important role in tumorigenesis and metastasis. This study is to identify novel microRNAs and their targets in order to understand the molecular mechanisms underlying OSCC and metastasis using label-free proteomics and microRNA microarray techniques. Human oral tissue biopsies from three groups of subjects who had benign, localized carcinoma and distal carcinoma were collected from the archived tissue bank at Pathology in Creighton University. Total RNA and proteins were extracted from the core biopsy of the same subject. MicroRNA identification was performed by using Affymetrix GeneChip miRNA arrays and comprehensive data analysis. Protein was analyzed by using label-free LTQ orbit trap mass spectrometry. Forty-four miRNAs were upregulated significantly, including let-7b, miR-720, miR-21, and miR-1274b, while 41 miRNAs were remarkably downregulated, including miR-195, and miR-932, at localized and distal carcinoma compared to benign tissues. Additionally, as compared to benign, 38 miRNAs upregulated at local carcinoma were downregulated significantly at distal carcinoma, while other 17 miRNAs downregulated significantly at localized carcinoma were upregulated gigantically at distal carcinoma. Those miRNAs were further validated by qRT-PCR and FISH. Among those upregulated at both local and distal, miR-720 was further studied, and tryptase alpha-1 as its target was identified. MicroRNA-720 mimics suppressed significantly the expression of tryptase alpha-1 in cultured human OSCC stem cell lines. Results from miR-720 tissue microarray analysis showed that 98.8% of sensitivity and 100% of specificity for OSCC detection were achieved, suggesting that miR-720 may be developed as a novel biomarker for detection of human OSCC. Citation Format: Gary Guishan Xiao, Min Cao. MicroRNA regulation of oral squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 487.

Stationary states and rotational properties of spin–orbit-coupled Bose–Einstein condensates held under a toroidal trap

We consider a pseudospin-1/2 Bose–Einstein condensate with Rashba spin–orbit coupling in a two-dimensional toroidal trap. By solving the damped Gross–Pitaevskii equations for this system, we show that the system exhibits a rich variety of stationary states, such as vehicle wheel and flower-petal stripe patterns. These stationary states are stable against perturbation with thermal energy and can survive for a long time. In the presence of rotation, our results show that the rotating systems have exotic vortex configurations. These phenomenon originates from the interplay among spin–orbit coupling, trap geometry, and rotation.

729 Noninvasive detection and analysis of ceramide in skin and blood in Chinese healthy population

Methods: The forearm cortical skin stratum corneum samples were obtained from 11 healthy subjects by a non-invasive method that cyanoacrylate adhesive method after signing the informed consent form; 4 blood samples were obtained by intravenous blood collection after written informed consent. Identification of ceramide in skin and blood samples is used by UltimateTM3000 high performance liquid chromatography coupled with Q - Exactive TM quadrupole - electrostatic field orbital trap. Data was analyzed using full-flow lipid analysis software (Lipid Search) after collected. Results: Experiments were performed on 11 skin samples and 4 blood samples for ceramide characterization. Peaks can be seen in all skin samples with response intensities between 105 and 107, with peaks in some blood sample. Positive ions and negative ions were collected respectively for the samples. Except for the target ceramides reported in the literature, more than 300 other lipids were detected under positive ion conditions and more than 30 were detected under negative ion conditions, the results show that the ceramides in the skin samples are mainly long-chain ceramides and the blood samples are mainly short-chain ceramides. Conclusion: In this experiment, the qualitative analysis of ceramide in the samples can be carried out quickly and easily under the premise of maximizing the noninvasive and the differences in the distribution of ceramides in different tissues of the human body are demonstrated, indicating the importance of ceramide for skin barrier and the application prospect in the cosmetics industry.

Building CX peanut-shaped disk galaxy profiles

Context. We present and discuss the orbital content of a rather unusual rotating barred galaxy model, in which the three-dimensional (3D) family, bifurcating from x1 at the 2:1 vertical resonance with the known “frown-smile” side-on morphology, is unstable. Aims. Our goal is to study the differences that occur in the phase space structure at the vertical 2:1 resonance region in this case, with respect to the known, well studied, standard case, in which the families with the frown-smile profiles are stable and support an X-shaped morphology. Methods. The potential used in the study originates in a frozen snapshot of an N-body simulation in which a fast bar has evolved. We follow the evolution of the vertical stability of the central family of periodic orbits as a function of the energy (Jacobi constant) and we investigate the phase space content by means of spaces of section. Results. The two bifurcating families at the vertical 2:1 resonance region of the new model change their stability with respect to that of most studied analytic potentials. The structure in the side-on view that is directly supported by the trapping of quasi-periodic orbits around 3D stable periodic orbits has now an infinity symbol (i.e. ∞-type) profile. However, the available sticky orbits can reinforce other types of side-on morphologies as well. Conclusions. In the new model, the dynamical mechanism of trapping quasi-periodic orbits around the 3D stable periodic orbits that build the peanut, supports the ∞-type profile. The same mechanism in the standard case supports the X shape with the frown-smile orbits. Nevertheless, in both cases (i.e. in the new and in the standard model) a combination of 3D quasi-periodic orbits around the stable x1 family with sticky orbits can support a profile reminiscent of the shape of the orbits of the 3D unstable family existing in each model.

An Orbital Trap Mass Analyzer Using a Hybrid Magnetic-Electric Field: A Simulation Study.

An orbital ion trap mass analyzer employing hybrid magnetic-electric field was designed and simulated. The trap has a rotational symmetrical structure and the hybrid trapping field was created in a toroidal space between 12 pairs of sector detection electrodes. Ion injection and ion orbital motion inside the trap were simulated using SIMION 8.1 with a user Lua program, and the required electric and magnetic field were investigated. The image charge signal can be picked up by the 12 pairs of detection electrodes and the mass resolution was evaluated using FFT. The simulated resolving power for the optimized configuration over 79,000 FWHM was obtained at the magnetic induction intensity of 0.5 Tesla in the simulation. Graphical Abstract ᅟ.

Velocity space resolved absolute measurement of fast ion losses induced by a tearing mode in the ASDEX Upgrade tokamak

Absolute flux of fast ion losses induced by tearing modes have been measured by means of fast ion loss detectors (FILD) for the first time in RF heated plasmas in the ASDEX Upgrade tokamak. Up to 30 MW m−2 of fast ion losses are measured by FILD at 5 cm from the separatrix, consistent with infra-red camera measurements, with energies in the range of 250–500 keV and pitch angles corresponding to large trapped orbits. A resonant interaction between the fast ions in the high energy tail of the ICRF distribution and a m/n = 5/4 tearing mode leads to enhanced fast ion losses. Around % of the fast ion losses are found to be coherent with the mode and scale linearly with its amplitude, indicating the convective nature of the transport mechanism. Simulations have been carried out to estimate the contribution of the prompt losses. A good agreement is found between the simulated and the measured velocity space of the losses. The velocity space resonances that may be responsible for the enhanced fast ion losses are identified.

The Visualization of Spherical Patterns with Symmetries of the Wallpaper Group

By constructing invariant mappings associated with wallpaper groups, this paper presents a simple and efficient method to generate colorful wallpaper patterns. Although the constructed mappings have simple form and only two parameters, combined with the color scheme of orbit trap algorithm, such mappings can create a great variety of aesthetic wallpaper patterns. The resulting wallpaper patterns are further projected by central projection onto the sphere. This creates the interesting spherical patterns that possess infinite symmetries in a finite space.

Phospholipid species distribution patterns in the mouse vascular organ of the lamina terminalis during systemic inflammation

Omega-3 fatty acids (3-FAs) modulate inflammation and brain-controlled febrile responses during inflammation. Here, we aimed to characterize the distribution and relative concentrations of several lipids (e.g. phosphatidylcholine, PC) including 3-FA-carrying lipids in a brain structure important for immune-to- brain communication, namely the vascular organ of the lamina terminalis (OVLT), during systemic lipopolysaccharide (LPS)-induced inflammation. For this purpose, wild type and fat-1 transgenic mice which produce large quantities of omega 3-FA endogenously, were stimulated with LPS (i.p., 2.5 mg/kg) or saline. Animals were sacrificed (5 h, 24 h), brains and blood samples were collected and analyzed by immunohistochemistry, high-resolution atmospheric-pressure scanning microprobe matrix assisted laser desorption/ionization ion source combined with an orbital trapping mass spectrometer and bioassays, respectively. Telemetric recordings revealed moderate hypothermia in LPS-treated fat-1 mice but fever in wildtype counterparts. Moreover, depending on genotypes and treatment, several distinct distribution patterns were observed for putative inflammation-involved phospholipids [e.g. PC(38:6), LysoPC(16:0)/(18:0), PE (P-36:4)] ranging from equal distributions, accumulation or absence within the OVLT compared to adjacent brain tissue. A localized increase of LysoPCs was indicative of enhanced LPS-induced turnover of fatty acid metabolism in the OVLT in fat-1 mice compared to wild type controls. Overall, screening of lipid distribution patterns revealed distinct inflammation-induced changes in the OVLT highlighting its prominent role for lipid metabolism and brain inflammation. New candidates for brain inflammation and immune-to-brain communication have been detected.

Spectrum Effect Relationship and Component Knock-Out in Angelica Dahurica Radix by High Performance Liquid Chromatography-Q Exactive Hybrid Quadrupole-Orbitrap Mass Spectrometer.

Different extracts of Angelica dahuricae were available for whitening or treating vitiligo clinically. They showed inhibitory or activating effects on tyrosinase, a rate-limiting enzyme of melanogenesis. This study aimed to identify active compounds on tyrosinase in water extract of Angelica dahurica Radix. We applied spectrum-effect relationship and component knock-out methods to make it clear. HPLC was used to obtain the specific chromatograms. The effects on tyrosinase activity were examined by measuring the oxidation rate of levodopa in vitro. Partial least squares method was used to examine the spectrum-effect relationships. The knocked-out samples were prepared by HPLC method, and the identification of knocked-out compounds was conducted by the high performance liquid chromatography-four stage rod-electrostatic field orbit trap high resolution mass spectrometry. Results showed that S6, S14, S18, S21, S35, S36, S37, S40, and S41 were positively correlated to inhibitory activity of Angelica dahuricae on tyrosinase whereas S9, S11, S8, S12, S22, and S30 were negatively correlated. When the concentration of each sample was 1 g·mL−1, equal to the amount of raw medicinal herbs, oxypeucedanin hydrate, imperatorin, cnidilin, and isoimperatorin had inhibitory effects on tyrosinase activity whereas byakangelicin and bergapten had activating effects.

Models of bars - I. Flattish profiles for early-type galaxies

We introduce a simple family of barred galaxy models with flat rotation curves. They are built by convolving the axisymmetric logarithmic model with a needle density. The density contours in the bar region are highly triaxial and elongated, but become spheroidal in the outer parts. The mass distribution differs markedly from the elliptical shape assumed in other analytical models, like Ferrers or Freeman bars. The surface density profile along the bar major axis is flattish, as befits models for bars in early-type galaxies (SB0, SBa). The two-dimensional orbital structure of the models is analysed with surfaces of section and characteristic diagrams and it reveals qualitatively new features. For some pattern speeds, additional Lagrange points can exist along the major axis, and give rise to off-centered, trapped orbits. When the bar is weak, the orbital structure is very simple, comprising just prograde, aligned $x_1$ orbits and retrograde anti-aligned $x_4$ orbits. As the bar strength increases, the $x_1$ family becomes unstable and vanishes, with propeller orbits dominating the characteristic diagram.