cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Quasiparticle excitations in a one-dimensional interacting topological insulator: Application for dopant-based quantum simulation
Creators: name: Mikhail, David
name: Voisin, Benoit
name: Medar, Dominique Didier St
name: Buchs, Gilles
name: Rogge, Sven
name: Rachel, Stephan
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the effects of electron-electron interactions on the charge excitation spectrum of the spinful Su-Schrieffer-Heeger (SSH) model, a prototype of a 1D bulk obstructed topological insulator. In view of recent progress in the fabrication of dopant-based quantum simulators we focus on experimentally detectable signatures of interacting topology in finite lattices. To this end we use Lanczos-based exact diagonalization to calculate the single-particle spectral function in real space which generalizes the local density of states to interacting systems. Its spatial and spectral resolution allows for the direct investigation and identification of edge states. By studying the non-interacting limit, we demonstrate that the topological in-gap states on the boundary are robust against both finite-size effects as well as random bond and onsite disorder which suggests the feasibility of simulating the SSH model in engineered dopant arrays in silicon. While edge excitations become zero-energy spin-like for any finite interaction strength, our analysis of the spectral function shows that the single-particle charge excitations are gapped out on the boundary. Despite the loss of topological protection we find that these edge excitations are quasiparticle-like as long as they remain within the bulk gap. Above a critical interaction strength of $U_c\approx 5 t$ these quasiparticles on the boundary loose their coherence which is explained by the merging of edge and bulk states. This is in contrast to the many-body edge excitations which survive the limit of strong coupling, as established in the literature. Our findings show that for moderate repulsive interactions the non-trivial phase of the interacting SSH model can be detected through remnant signatures of topological single-particle states using single-particle local measurement techniques such as scanning tunneling spectroscopy.
description: 16 pages + 13 figures; v2: final version
Dual Parton Model for the Charged Multiplicity in pp Collisions at 13, 13.6 TeV and for future LHC energy of 27 TeV
Creators: name: Damuka, Pranay K.
name: Aggarwal, R.
name: Kaur, M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Analysis of the charged multiplicity in proton-proton inelastic interactions at the LHC energies in the setting of Dual Parton Model is presented. Data from the CMS experiment and the data simulated at different energies in various pseudo-rapidity windows using the event generator PYTHIA8are analysed and compared with the calculations from the model. Each inelastic scattering is assumed to follow the Poisson distribution. The theoretical Koba-Nielsen-Olesen (KNO) scaling of the multiplicity distributions is studied and compared with previously published experimental results at $\sqrt{s}$ = 0.9, 2.36, 7 TeV. Predictions from the model for the KNO distributions at $\sqrt{s}$ = 13, 13.6 TeV and for the future LHC energy of 27 TeV are computed and compared with the simulated data.
description: 10 pages, 9 Figures, 2 Tables, 38 References
Use of micellar electrokinetic chromatography to measure palmitoylation of a peptide
Creators: name: BORLAND, L
name: ALLBRITTON, N
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2008

description: Palmitoylation is the thioester linkage of the fatty acid, palmitate (C16:0), to cysteine residues on a protein or peptide. This dynamic and reversible post-translational modification increases the hydrophobicity of proteins/peptides, facilitating protein-membrane interactions, protein-protein interactions and intracellular trafficking of proteins. Manipulation of palmitoylation provides a new mechanism for control over protein location and function, which may lead to better understanding of cell signaling disorders, such as cancer. Unfortunately, few methods exist to quantitatively monitor protein or peptide palmitoylation. In this study, a capillary electrophoresis-based assay was developed, using MEKC, to measure palmitoylation of a fluorescently-labeled peptide in vitro. A fluorescently-labeled peptide derived from the growth-associated protein, GAP-43, was palmitoylated in vitro using palmitoyl coenzyme A. Formation of a doubly-palmitoylated GAP-peptide product was confirmed by mass spectroscopy. The GAP-peptide substrate was separated from the palmitoylated peptide product in under 7 minutes by MEKC. The rate of in vitro palmitoylation with respect to reaction time, GAP-peptide concentration, pH, and inhibitor concentration were also examined. This capillary electrophoresis-based assay for monitoring palmitoylation has applications in biochemical studies of acyltransferases and thioesterases as well as in the screening of acyltransferase and thioesterase inhibitors for drug development.
Six-loop anomalous dimension of the $ϕ^Q$ operator in the $O(N)$ symmetric model
Creators: name: Bednyakov, Alexander
name: Pikelner, Andrey
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: A technique of large-charge expansion provides a novel opportunity for calculation of critical dimensions of operators $ϕ^Q$ with fixed charge $Q$. In the small-coupling regime the polynomial structure of the anomalous dimensions can be fixed from a number of direct perturbative calculations for a fixed $Q$. At the six-loop level one needs to include new diagrams that correspond to operators with five or more legs. The latter never appeared before in scalar-theory calculations. Here we show how to compute the anomalous dimension of the operator $ϕ^{Q=5}$ at the six-loop order. In combination with results for operators with $Q<5$, which are extracted from the six-loop beta-functions for general scalar theory, and with predictions from the large-charge expansion, our calculation allows us to derive the answer for general-$Q$ anomalous dimensions. At the critical point resummation in three dimensions enables us to compare the critical exponents with results of Monte-Carlo simulations and large-$N$ predictions.
description: results in ancillary files
Analysis of 8-oxo-7,8-dihydro-2′-deoxyguanosine by ultra high pressure liquid chromatography–heat assisted electrospray ionization–tandem mass spectrometry
Creators: name: Luke, April M.
name: Pachkowski, Brian F.
name: Liao, Shengkai
name: Boysen, Gunnar
name: Swenberg, James A.
name: Collins, Leonard B.
name: Watters, Joanne L.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2010

description: Increased amounts of reactive oxygen species (ROS), generally termed oxidative stress, are frequently hypothesized to be causally associated with many diseases. Analyses of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxo-dG) in DNA and urine are widely used biomarkers for oxidative stress. Over the years it became clear that analysis of 8-oxo-dG in DNA is challenging due to artifactual formation during sample work up. The present study demonstrates that 8-oxo-dG can be measured reliably and accurately when appropriate precautions are taken. First, the presence of an antioxidant, metal chelator, or free radical trapping agent during sample preparation improves reproducibility. Second, sample enrichment by HPLC fraction collection was used to optimize sensitivity. Third, heat assisted electrospray ionization (HESI) eliminated potential interferences and improved assay performance and sensitivity. Subsequently, the UPLC–HESI–MS/MS method was applied to show the biphasic dose response of 8-oxo-dG in H2O2-treated HeLa cells. Application of this method to human lymphocyte DNA (n = 156) gave a mean±SD endogenous amount of 1.57±0.88 adducts per 106 dG, a value that is in agreement with the suggested amount previously estimated by European Standard Committee on Oxidative DNA Damage (ESCODD) and others. These results suggest that the present method is well suited for application to molecular toxicology and epidemiology studies investigating the role of oxidative stress.
Investigation of the 1+1 dimensional Thirring model using the method of matrix product states
Creators: name: Banuls, Mari Carmen
name: Cichy, Krzysztof
name: Kao, Ying-Jer
name: Lin, C. -J. David
name: Lin, Yu-Ping
name: Tan, David T. -L
Publisher: name: arXiv
Year: 2018
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We present preliminary results of a study on the non-thermal phase structure of the (1+1) dimensional massive Thirring model, employing the method of matrix product states. Through investigating the entanglement entropy, the fermion correlators and the chiral condensate, it is found that this approach enables us to observe numerical evidence of a Kosterlitz-Thouless phase transition in the model.
description: 7 pages, 4 figures; contribution to the proceedings of Lattice 2018 conference
Equilibrium and non-equilibrium dynamics of a hole in a bilayer antiferromagnet
Creators: name: Nyhegn, Jens H.
name: Nielsen, Kristian K.
name: Bruun, Georg M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The dynamics of charge carriers in lattices of quantum spins is a long standing and fundamental problem. Recently, a new generation of quantum simulation experiments based on atoms in optical lattices has emerged that gives unprecedented insights into the detailed spatial and temporal dynamics of this problem, which compliments earlier results from condensed matter experiments. Focusing on observables accessible in these new experiments, we explore here the equilibrium as well as non-equilibrium dynamics of a mobile hole in two coupled antiferromagnetic spin lattices. Using a self-consistent Born approximation, we calculate the spectral properties of the hole in the bilayer and extract the energy bands of the quasiparticles, corresponding to magnetic polarons that are either symmetric or anti-symmetric under layer exchange. These two kinds of polarons are degenerate at certain momenta due to the antiferromagnetic symmetry, and we, furthermore, examine how the momentum of the ground state polaron depends on the interlayer coupling strength. The long time dynamics of a hole initially created in one layer is shown to be characterised by oscillations between the two layers with a frequency given by the energy difference between the symmetric and the anti-symmetric polaron. We finally demonstrate that the expansion velocity of a hole initially created at a given lattice site is governed by the ballistic motion of polarons. It moreover depends non-monotonically on the interlayer coupling, eventually increasing as a quantum phase transition to a disordered state is approached.
[Halle (Saale), Universitäts- und Landesbibliothek Sachsen-Anhalt, Morbio 4 (33)]
Creators: name: (:Unkn) Unknown
Publisher: name: Universitäts- und Landesbibliothek Sachsen-Anhalt
Year: 1306
Subjects: subject: Sonstige weltliche Aussteller
subject: Notarsurkunde
subject: Urkunde
subject: 090

description: [...]us de Acio, Sohn des verstorbenen Petrus de Acio, und zahlreiche weitere genannte Personen versichern, von Oto de Nibia, genannt Lucrum, aus Novara von allen Zahlungen entbunden worden zu sein.
Thermalization and chaos in a 1+1d QFT
Creators: name: Delacretaz, Luca V.
name: Fitzpatrick, A. Liam
name: Katz, Emanuel
name: Walters, Matthew T.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study aspects of chaos and thermodynamics at strong coupling in a scalar model using LCT numerical methods. We find that our eigenstate spectrum satisfies Wigner-Dyson statistics and that the coefficients describing eigenstates in our basis satisfy Random Matrix Theory (RMT) statistics. At weak coupling, though the bulk of states satisfy RMT statistics, we find several scar states as well. We then use these chaotic states to compute the equation of state of the model, obtaining results consistent with Conformal Field Theory (CFT) expectations at temperatures above the scale of relevant interactions. We also test the Eigenstate Thermalization Hypothesis by computing the expectation value of local operators in eigenstates, and check that their behavior is consistent with thermal CFT values at high temperatures. Finally, we compute the Spectral Form Factor (SFF), which has the expected behavior associated with the equation of state at short times and chaos at long times. We also propose a new technique for extracting the connected part of the SFF without the need of disorder averaging by using different symmetry sectors.
description: 17 pages, 18 figures; v2: added Fig.10 on quantum scars, published version
Hide and Seek: Screened Scalar Fields in Hydrogen and Muonium
Creators: name: Brax, Philippe
name: Davis, Anne-Christine
name: Elder, Benjamin
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We compute bounds on screened scalar field theories from hydrogen-like systems. New light scalar fields generically have a direct coupling to matter. Such a coupling is strongly constrained by myriad experimental measurements. However, certain theories possess a {\it screening mechanism} that allows the effects of this coupling to weaken dynamically, and to evade many such bounds. We compute the perturbations to the energy levels of hydrogen-like systems due to screened scalar fields. We then use this result in two ways. First, we compute bounds from hydrogen spectroscopy, finding significantly weaker bounds than have been reported before as screening effects were overlooked. Second, we show that muonium is an intrinsically much more sensitive probe of screened scalar fields. For chameleon models, muonium experiments probe a large part of the parameter space that is as yet unexplored by low energy physics and has so far only been tested by high-energy particle physics experiments.
description: 20 pages, 3 figures
A 3D view of the Hydra I cluster core - II. Stellar populations
Creators: name: Barbosa, Carlos Eduardo
name: Arnaboldi, Magda
name: Hilker, Michael
name: Coccato, Lodovico
name: Richtler, Tom
name: de Oliveira, Cláudia Mendes
Publisher: name: arXiv
Year: 2014
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Several observations of the central region of the Hydra I galaxy cluster point to a multi-epoch assembly history. Using our novel FORS2/VLT spectroscopic data set, we were able to map the luminosity-weighted age, [Fe/H] and [$α$/Fe] distributions for the stellar populations around the cD galaxy NGC 3311. Our results indicate that the stellar populations follow the trends of the photometric substructures, with distinct properties that may aid to constrain the evolutionary scenarios for the formation of the cluster core.
description: Barbosa et al. 2014, in IAU Symp. 309, "Galaxy in 3D across the Universe", B. L. Ziegler, F. Combes, H. Dannerbauer, M. Verdugo, Eds. (Cambridge: Cambridge Univ. Press), in press
A lensed protocluster candidate at $z=7.66$ identified in JWST observations of the galaxy cluster SMACS0723-7327
Creators: name: Laporte, N.
name: Zitrin, A.
name: Dole, H.
name: Roberts-Borsani, G.
name: Furtak, L. J.
name: Witten, C.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: According to the current paradigm of galaxy formation, the first galaxies have been likely formed within large dark matter haloes. The fragmentation of these massive haloes led to the formation of galaxy protoclusters, which are usually composed of one to a few bright objects, surrounded by numerous fainter (and less massive) galaxies. These early structures could have played a major role in reionising the neutral hydrogen within the first billion years of the Universe; especially, if their number density is significant.Taking advantage of the unprecedented sensitivity reached by the \textit{James Webb Space Telescope (JWST)}, galaxy protoclusters can now be identified and studied in increasing numbers beyond $z\geq\ $6. Characterising their contribution to the UV photon budget could supply new insights into the reionisation process. We analyse the first JWST dataset behind SMACS0723-7327 to search for protoclusters at $z\geq6$, combining the available spectroscopic and photometric data. We then compare our findings with semi-analytical models and simulations. In addition to two bright galaxies ($\leq$26.5 AB in F277W), separated by $\sim$11\arcsec and spectroscopically confirmed at $z_{spec}=7.66$, we identify 6 additional galaxies with similar colors in a $θ\sim20$\arcsec radius around these (corresponding to R$\sim60-90$ kpc in the source plane). Using several methods, we estimate the mass of the dark matter halo of this protocluster, $\sim$3.3$\times$10$^{11}$M$_{\odot}$ accounting for magnification, consistent with various predictions. The physical properties of all protocluster members are also in excellent agreement with what has been previously found at lower redshifts: star-formation main sequence and protocluster size. This detection adds to just a few protoclusters currently known in the first billion years of the universe.
description: 7 pages, 6 Figures. Accepted for publication in A&A Letter
PRIMARY PROCESSING TECHNOLOGY OF SILK WASTE FOR USE IN SIMILAR INDUSTRIES
Creators: name: Muminov, O.
name: Sulaymonov, Sh.
name: Sotvoldiyeva, N.
Publisher: name: Zenodo
Year: 2023

description: Research has shown that in recent years the cocoon industry, technological processes from cocoon cultivation to production of silk products and the equipment used in these processes are improving. However, due to the fact that the quality of the cocoons grown in our republic does not correspond to such techniques and technologies, the output of silk fiber waste is still high, and it continues to be exported as raw materials without processing. Although the price of 1 kg of raw silk is 48-50 US dollars in the world market, depending on its assortment, the price of silk spun from its fiber waste is 70 US dollars. In the article, the issue of preliminary processing and effective use of fiber waste of coir raw materials is widely covered.
Hydrogen adsorption in metal-organic frameworks: the role of nuclear quantum effects
Creators: name: Wahiduzzaman, Mohammad
name: Walther, Christian F. J.
name: Heine, Thomas
Publisher: name: arXiv
Year: 2014
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: The role of nuclear quantum effects on the adsorption of molecular hydrogen in metal-organic frameworks (MOFs) has been investigated on grounds of Grand-Canonical Quantized Liquid Density-Functional Theory (GC-QLDFT) calculations. For this purpose, we have carefully validated classical H2 -host interaction potentials that are obtained by fitting Born-Oppenheimer ab initio reference data. The hydrogen adsorption has first been assessed classically using Liquid Density-Functional Theory (LDFT) and the Grand-Canonical Monte Carlo (GCMC) methods. The results have been compared against the semi-classical treatment of quantum effects by applying the Feynman-Hibbs correction to the Born-Oppenheimer-derived potentials, and by explicit treatment within the Grand-Canonical Quantized Liquid Density-Functional Theory (GC-QLDFT). The results are compared with experimental data and indicate pronounced quantum and possibly many-particle effects. After validation calculations have been carried out for IRMOF-1 (MOF-5), GC-QLDFT is applied to study the adsorption of H2 in a series of MOFs, including IRMOF-4, -6, -8, -9, -10, -12, -14, -16, -18 and MOF-177. Finally, we discuss the evolution of the H2 quantum fluid with increasing pressure and lowering temperature.
Occupational exposure to HDI: Progress and challenges in biomarker analysis
Creators: name: Flack, Sheila L.
name: Nylander-French, Leena A.
name: Ball, Louise M.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2010

description: 1,6-hexamethylene diisocyanate (HDI) is extensively used in the automotive repair industry and is a commonly reported cause of occupational asthma in industrialized populations. However, the exact pathological mechanism remains uncertain. Characterization and quantification of biomarkers resulting from HDI exposure can fill important knowledge gaps between exposure, susceptibility, and the rise of immunological reactions and sensitization leading to asthma. Here, we discuss existing challenges in HDI biomarker analysis including the quantification of N-acetyl-1,6-hexamethylene diamine (monoacetyl-HDA) and N,N′-diacetyl-1,6-hexamethylene diamine (diacetyl-HDA) in urine samples based on previously established methods for HDA analysis. In addition, we describe the optimization of reaction conditions for the synthesis of monoacetyl-HDA and diacetyl-HDA, and utilize these standards for the quantification of these metabolites in the urine of three occupationally exposed workers. Diacetyl-HDA was present in untreated urine at 0.015 – 0.060 μg/l. Using base hydrolysis, the concentration range of monoacetyl-HDA in urine was 0.19 – 2.2 μg/l, 60-fold higher than in the untreated samples on average. HDA was detected only in one sample after base hydrolysis (0.026 μg/l). In contrast, acid hydrolysis yielded HDA concentrations ranging from 0.36 to 10.1 μg/l in these three samples. These findings demonstrate HDI metabolism via N-acetylation metabolic pathway and protein adduct formation resulting from occupational exposure to HDI.
Quantifying the HIV-1 integrase inhibitor raltegravir in female genital tract secretions using high-performance liquid chromatography with ultraviolet detection
Creators: name: Rezk, Naser L.
name: Talameh, Jasmine A.
name: Kashuba, Angela D.M.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2010

description: Understanding the pharmacokinetics of drugs in peripheral body compartments, such as the genital tract, is particularly important in the infectious diseases arena. However, extracting drugs from small volumes of viscous, proteinacious substances like cervicovaginal fluid is particularly challenging. The goal of this study was to develop a method to quantify raltegravir, an HIV-1 integrase inhibitor, in the female genital tract. The method included sample preparation with perchloric acid followed by solid-phase extraction, separation with reverse-phase high-performance liquid chromatography, and detection with an ultraviolet wavelength of 218 nm. The method was linear from 0.05 to 10.0 mg/L, with minimal endogenous interference. The method was accurate (1.2–11.0% deviation) and precise (1.1–12.6% CV) for both within and between-day analyses. The ability to detect raltegravir in the female genital tract is essential for future investigations of raltegravir as an agent for prevention of HIV acquisition, and this method will be used for clinical studies further evaluating pharmacokinetic–pharmacodynamic relationships in this body compartment.
Tensor Networks and their use for Lattice Gauge Theories
Creators: name: Bañuls, Mari Carmen
name: Cichy, Krzysztof
name: Cirac, J. Ignacio
name: Jansen, Karl
name: Kühn, Stefan
Publisher: name: arXiv
Year: 2018
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: Tensor Network States are ansätze for the efficient description of quantum many-body systems. Their success for one dimensional problems, together with the fact that they do not suffer from the sign problem and can address the simulation of real time evolution, have turned them into one of the most promising techniques to study strongly correlated systems. In the realm of Lattice Gauge Theories they can offer an alternative to standard lattice Monte Carlo calculations, which are suited for static properties and regimes where no sign problem appears. The application of Tensor Networks to this kind of problems is a young but rapidly evolving research field. This paper reviews some of the recent progress in this area, and how, using one dimensional models as testbench, some fundamental milestones have been reached that may pave the way to more ambitious goals.
description: Contribution to the proceedings of the 36th Annual International Symposium on Lattice Field Theory - LATTICE2018, 22-28 July, 2018 Michigan State University, East Lansing, Michigan, USA. Bibliography updated in second version
[Halle (Saale), Universitäts- und Landesbibliothek Sachsen-Anhalt, Morbio 4 (35)]
Creators: name: , Jacobus
Publisher: name: Universitäts- und Landesbibliothek Sachsen-Anhalt
Year: 1307
Subjects: subject: Sonstige weltliche Aussteller
subject: Notarsurkunde
subject: Urkunde
subject: 090

description: Jacobus aus Oggiono, Sohn des Petrus, seinerseits genannt Peracha de Dalfinis, missus und procurator seines Vaters, beendet gegenüber Bartholomeus de Parma, Abt des Klosters von Civate, die Pacht eines Grundstücks, gelegen in Oggiono.
Spatial structure of the color field in the SU(3) flux tube
Creators: name: Baker, M.
name: Cea, Paolo
name: Chelnokov, Volodymyr
name: Cosmai, Leonardo
name: Cuteri, Francesca
name: Papa, Alessandro
Publisher: name: arXiv
Year: 2018
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We report on the chromoelectric and chromomagnetic fields generated by a static quark-antiquark pair at zero temperature in pure gauge SU(3). From the spatial structure of chromoelectric field we extract its nonperturbative part and discuss its properties.
description: 7 pages, 3 figures, 2 tables, originally presented at the 36th Annual International Symposium on Lattice Field Theory, 22-28 July, 2018, Michigan State University, East Lansing, Michigan, USA
Calcium oscillation on homogeneous and heterogeneous networks of ryanodine receptor
Creators: name: Gao, Zhong-Xue
name: Li, Tian-Tian
name: Jiang, Han-Yu
name: He, Jun
Publisher: name: arXiv
Year: 2022
Subjects: subject: Subcellular Processes (q-bio.SC)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: Calcium oscillation is an important calcium homeostasis, imbalance of which is the key mechanism of initiation and progression of many major diseases. The formation and maintenance of calcium homeostasis are closely related to the spatial distribution of calcium channels. In the current paper, a theoretical framework is established by abstracting the spatial distribution of the calcium channels as a nonlinear biological complex network with calcium channels as nodes and Ca$^{2+}$ as edges. A dynamical model for a RyR is adopted to investigate the effect of spatial distribution on calcium oscillation. The mean-field model can be well reproduced from the complete graph and dense Erdös-Rényi network. The synchronization of RyRs is found important to generate a global calcium oscillation. The clique graph with a cluster structure can not produce a global oscillation due to the failure of synchronization between clusters. A more realistic geometric network is constructed in a two-dimensional plane based on the experimental information about the RyR arrangement of clusters and the frequency distribution of cluster sizes. Different from the clique graph, the global oscillation can be generated with reasonable parameters on the geometric network. The simulation also suggests that existence of small clusters and rogue RyR's plays an important role in the maintenance of global calcium oscillation through keeping synchronization between large clusters. Such results support the heterogeneous distribution of RyR's with different-size clusters, which is helpful to understand recent observations with super resolution nanoscale imaging techniques. The current theoretical framework can also be extent to investigate other phenomena in calcium signal transduction.
description: 14 pages, 8 figures, to be published in Phys. Rev. E
Validation and application of a liquid chromatography–tandem mass spectrometric method for quantification of the drug transport probe fexofenadine in human plasma using 96-well filter plates
Creators: name: Stanton, Melonie L.
name: Joy, Melanie S.
name: Frye, Reginald F.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2010

description: A rapid method to determine fexofenadine concentrations in human plasma using protein precipitation in 96-well plates and liquid chromatography-tandem mass spectrometry was validated. Plasma proteins were precipitated with acetonitrile containing the internal standard fexofenadine-d6, mixed briefly, and then filtered into a collection plate. The resulting filtrate was diluted and injected onto a Phenomenex Gemini C18 (50 × 2.0 mm, 5 micron) analytical column. The mobile phase consisted of 0.1% formic acid, 5 mM ammonium acetate in deionized water and methanol (35:65, v/v). The flow rate was 0.2 ml/min and the total run time was 2 min. Detection of the analytes was achieved using positive ion electrospray ionization and high resolution multiple reaction monitoring mode (H-SRM). The linear standard curve ranged from 1 to 500 ng/ml and the precision and accuracy (intra- and inter-run) were within 4.3% and 8.0%, respectively. The method has been applied successfully to determine fexofenadine concentrations in human plasma samples obtained from subjects administered a single oral dose of fexofenadine. The method is rapid, sensitive, selective and directly applicable to human pharmacokinetic studies involving fexofenadine.
Development of a liquid chromatography–tandem mass spectrometry assay of six antimicrobials in plasma for pharmacokinetic studies in premature infants
Creators: name: White, Nicole R.
name: Cohen-Wolkowiez, Michael
name: Benjamin, Daniel K.
name: Kashuba, Angela D.M.
name: Bridges, Arlene
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2011

description: This method provides a simple extraction procedure, as well as a validated, sensitive, and specific liquid chromatography-tandem mass spectrometry assay for the simultaneous quantification of ampicillin, piperacillin, tazobactam, meropenem, acyclovir, and metronidazole in human plasma. The method was validated over concentration ranges specific for each compound, with a lower limit of quantification of 50–300 ng/mL and a sample volume of 50 μL. The method is accurate and precise, with within- and between-day accuracy ranging from 85–110% and 92–110%, respectively, and within- and between-day precision of 89–111% and 91–109%, respectively. Simplicity, low plasma volume, and high throughput make this method suitable for clinical pharmacokinetic studies in premature infants.
Separation of fluorescently labeled phosphoinositides and sphingolipids by capillary electrophoresis
Creators: name: Sims, Christopher E.
name: Allbritton, Nancy L.
name: Wang, Kelong
name: Jiang, Dechen
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2012

description: Phosphoinositides (PIs) and sphingolipids regulate many aspects of cell behavior and are often involved in disease processes such as oncogenesis. Capillary electrophoresis with laser induced fluorescence detection (CE-LIF) is emerging as an important tool for enzymatic assays of the metabolism of these lipids, particularly in cell-based formats. Previous separations of phosphoinositide lipids by CE required a complex buffer with polymer additives which had the disadvantages of high cost and/or short shelf life. Further a simultaneous separation of these classes of lipids has not been demonstrated in a robust buffer system. In the current work, a simple separation buffer based on NaH2PO4 and 1-propanol was optimized to separate two sphingolipids and multiple phosphoinositides by CE. The NaH2PO4 concentration, pH, 1-propanol fraction, and a surfactant additive to the buffer were individually optimized to achieve simultaneous separation of the sphingolipids and phosphoinositides. Fluorescein-labeled sphingosine (SFL) and sphingosine 1-phosphate (S1PFL), fluorescein-labeled phosphatidyl-inositol 4,5-bisphosphate (PIP2) and phosphatidyl-inositol 3,4,5-trisphosphate (PIP3), and bodipy-fluorescein (BFL)-labeled PIP2 and PIP3 were separated pairwise and in combination to demonstrate the generalizability of the method. Theoretical plate numbers achieved were as high as 2×105 in separating fluorophore-labeled PIP2 and PIP3. Detection limits for the 6 analytes were in the range of 10−18 to 10−20 mol. The method also showed high reproducibility, as the relative standard deviation of the normalized migration time for each analyte in the simultaneous separation of all 6 compounds was less than 1%. The separation of a mixture composed of diacylglycerol (DAG) and multiple phosphoinositides was also demonstrated. As a final test, fluorescent lipid metabolites formed within cells loaded with BFLPIP2 were separated from a cell lysate as well as a single cell. This simple and robust separation method for SFL and S1PFL and various metabolites of phosphoinositide-related signal transduction is expected to enable improved enzymatic assays for biological and clinical applications.
The extended structure of the dwarf irregular galaxy Sagittarius
Creators: name: Beccari, G.
name: Bellazzini, M.
name: Fraternali, F.
name: Battaglia, G.
name: Perina, S.
name: Sollima, A.
name: Oosterloo, T. A.
name: Testa, V.
name: Galleti, S.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present a detailed study of the stellar and HI structure of the dwarf irregular galaxy Sagittarius. We use new deep and wide field photometry to trace the surface brightness profile of the galaxy out to ~5.0' (corresponding to ~1600 pc) and down to $μ_V\simeq 30.0$ mag/arcsec$^2$, thus showing that the stellar body of the galaxy is much more extended than previously believed, and it is similarly (or more) extended than the overall HI distribution. The whole major-axis profile is consistent with a pure exponential, with a scale radius of $\simeq 340$ pc. The surface density maps reveal that the distribution of old and intermediate-age stars is smooth and remarkably flattened out to its edges, while the associated HI has a much rounder shape, is off-centred and presents multiple density maxima and a significant hole. No clear sign of systemic rotation is detectable in the complex HI velocity field. No metallicity gradient is detected in the old and intermediate age population of the galaxy, and we confirm that this population has a much more extended distribution than young stars (age$\lt 1$ Gyr).
description: 11 pages, 14 figures, accepted for publication on A&A. arXiv admin note: text overlap with arXiv:1404.1697
QCD phase diagram for finite imaginary chemical potential with HISQ fermions
Creators: name: Goswami, Jishnu
name: Karsch, Frithjof
name: Lahiri, Anirban
name: Schmidt, Christian
Publisher: name: arXiv
Year: 2018
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We present results from an ongoing study of the phase diagram of (2+1)-flavor QCD using the HISQ action with smaller than physical light quark masses in the Roberge-Weiss (RW) plane on lattices with temporal extent $N_τ=4$. We find that the endpoint of the $1^{st}$ order RW transition line remains $2^{nd}$ order at least down to light quark masses corresponding to Goldstone pion masses of $55$ MeV. Furthermore, we show that the chiral condensate is sensitive to the RW transition and may serve as a energy-like operator characterizing universal behavior close to the RW endpoint.
description: 7pages, 11 figures, Prepared for the proceedings of LATTICE2018, held at Michigan State University, East Lansing, Michigan, USA
Giant slip length at a supercooled liquid-solid interface
Creators: name: Lafon, Suzanne
name: Chennevière, Alexis
name: Restagno, Frédéric
name: Merabia, Samy
name: Joly, Laurent
Publisher: name: arXiv
Year: 2022
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The effect of temperature on friction and slip at the liquid-solid interface has attracted attention over the last twenty years, both numerically and experimentally. However, the role of temperature on slip close to the glass transition has been less explored. Here, we use molecular dynamics to simulate a bi-disperse atomic fluid, which can remain liquid below its melting point (supercooled state), to study the effect of temperature on friction and slip length between the liquid and a smooth apolar wall, in a broad range of temperatures. At high temperatures, an Arrhenius law fits well the temperature dependence of viscosity, friction and slip length. In contrast, when the fluid is supercooled, the viscosity becomes super-Arrhenian, while interfacial friction can remain Arrhenian or even drastically decrease when lowering the temperature, resulting in a massive increase of the slip length. We rationalize the observed superlubricity by the surface crystallization of the fluid, and the incommensurability between the structures of the fluid interfacial layer and of the wall. This study calls for experimental investigation of the slip length of supercooled liquids on low surface energy solids.
DarkMix: Mixture Models for the Detection and Characterization of Dark Matter Halos
Creators: name: Hurtado-Gil, Lluís
name: Kuhn, Michael A.
name: Arnalte-Mur, Pablo
name: Feigelson, Eric D.
name: Martínez, Vicent
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Dark matter simulations require statistical techniques to properly identify and classify their halos and structures. Nonparametric solutions provide catalogs of these structures but lack the additional learning of a model-based algorithm and might misclassify particles in merging situations. With mixture models, we can simultaneously fit multiple density profiles to the halos that are found in a dark matter simulation. In this work, we use the Einasto profile (Einasto 1965, 1968, 1969) to model the halos found in a sample of the Bolshoi simulation (Klypin et al. 2011), and we obtain their location, size, shape and mass. Our code is implemented in the R statistical software environment and can be accessed on https://github.com/LluisHGil/darkmix.
description: 25 pages, 22 figures, 5 tables
Development of a tandem affinity phosphoproteomic method with motif selectivity and its application in analysis of signal transduction networks
Creators: name: Blackburn, Kevin
name: Goshe, Michael B.
name: Herring, Laura E.
name: Grant, Kyle G.
name: Haugh, Jason M.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2015

description: Phosphorylation is an important post-translational modification that is involved in regulating many signaling pathways. Of particular interest are the growth factor mediated Ras and phosphoinositide 3-kinase (PI3K) signaling pathways which, if misregulated, can contribute to the progression of cancer. Phosphoproteomic methods have been developed to study regulation of signaling pathways; however, due to the low stoichiometry of phosphorylation, understanding these pathways is still a challenge. In this study, we have developed a multi-dimensional method incorporating electrostatic repulsion-hydrophilic interaction chromatography (ERLIC) with tandem IMAC-TiO2 enrichment for subsequent phosphopeptide identification by LC/MS/MS. We applied this method to PDGF-stimulated NIH 3T3 cells to provide over 11,000 unique phosphopeptide identifications. Upon motif analysis, IMAC was found to enrich for basophilic kinase substrates while the subsequent TiO2 step enriched for acidophilic kinase substrates, suggesting that both enrichment methods are necessary to capture the full complement of kinase substrates. Biological functions that were over-represented at each PDGF stimulation time point, together with the phosphorylation dynamics of several phosphopeptides containing known kinase phosphorylation sites illustrate the feasibility of this approach in quantitative phosphoproteomic studies.
COMPARATIVE ANALYSIS OF AORTIC PARAMETERS IN HEALTHY AND SICK CHILDREN WITH VARIOUS HEART DEFECTS AT THE AGE OF 3 YEARS
Creators: name: Khamidova, Nigora
name: Baymuradov, Ravshan
Publisher: name: Zenodo
Year: 2023

description: A study of the size of the aorta and its parts in sick children with heart defects 3 years old in comparison with data from healthy children of the same age showed that not all studied indicators changed significantly in relation to the data from healthy children.
Association of vascular health and neurocognitive performance in overweight adults with high blood pressure
Creators: name: Smith, Patrick J.
name: Babyak, Michael A.
name: Sherwood, Andrew
name: Hinderliter, Alan
name: Blumenthal, James A.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2011

description: To examine the relationship between vascular health, including flow-mediated dilation (FMD), intima medial thickness (IMT), and neurocognitive performance in a sample of 124 sedentary, middle-aged adults with high blood pressure (SBP 130–159 mmHg or DBP 85–99 mmHg) who were overweight or obese (body mass index 25.0 – 39.99 kgs/m2). Patients completed a neuropsychological test battery including measures of Executive Function and Psychomotor Speed, along with measures of IMT and FMD. Hierarchical multiple regression analyses were used to investigate the association between vascular measures and neurocognitive performance after controlling for demographic factors and cerebrovascular risk factors. Higher levels of FMD predicted better Executive Function (b = 0.90, P = .045). Greater IMT tended to be associated with slower Psychomotor Speed (b = −0.82, P = .084), with the effect attenuated after controlling for FMD. Impaired FMD is associated with worse neurocognitive functioning among overweight adults with high blood pressure.
Complex magnetic ordering in CeGe1.76 studied by neutron diffraction
Creators: name: Jayasekara, W. T.
name: Tian, W.
name: Hodovanets, H.
name: Canfield, P. C.
name: Bud'ko, S. L.
name: Kreyssig, A.
name: Goldman, A. I.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Neutron diffraction measurements on a single crystal of CeGe1.76 reveal a complex series of magnetic transitions at low temperature. At T_N = 7 K, there is a transition from a paramagnetic state at higher temperature to an incommensurate magnetic structure characterized by a magnetic propagation vector (0 0 tau) with tau approx. 1/4 and the magnetic moment along the a axis of the orthorhombic unit cell. Below T_LI = 5 K, the magnetic structure locks in to a commensurate structure with tau = 1/4 and the magnetic moment remains along the a axis. Below T* = 4 K, we find additional half-integer and integer indexed magnetic Bragg peaks consistent with a second commensurately ordered antiferromagnetic state.
description: 7 pages, 8 figures
Complete SMEFT predictions for four top quark production at hadron colliders
Creators: name: Aoude, Rafael
name: Faham, Hesham El
name: Maltoni, Fabio
name: Vryonidou, Eleni
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study four top quark production at hadron colliders in the Standard Model Effective Field Theory (SMEFT). We perform an analysis at the tree-level, including all possible QCD- and EW-coupling orders and relevant dimension-six operators. We find several cases where formally subleading terms give rise to significant contributions, potentially providing sensitivity to a broad class of operators. Inclusive and differential predictions are presented for the LHC and a future $pp$ circular collider operating at $100$ TeV. We estimate the sensitivity of different operators and perform a simplified chi-square fit to set limits on SMEFT Wilson coefficients. In so doing, we assess the importance of including subleading terms and differential information in constraining new physics contributions. Finally, we compute the SMEFT predictions for the double insertion of dimension-six operators and scrutinise the possible enhancements to the sensitivity induced by a specific class of higher order terms in the EFT series.
description: 32 pages with tables and figures, v2: version accepted by JHEP
Gaussian states for the variational study of (1+1)-dimensional lattice gauge models
Creators: name: Sala, P.
name: Shi, T.
name: Kühn, S.
name: Bañuls, M. C.
name: Demler, E.
name: Cirac, J. I.
Publisher: name: arXiv
Year: 2018
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We introduce a variational ansatz based on Gaussian states for (1+1)-dimensional lattice gauge models. To this end we identify a set of unitary transformations which decouple the gauge degrees of freedom from the matter fields. Using our ansatz, we study static aspects as well as real-time dynamics of string breaking in two (1+1)-dimensional theories, namely QED and two-color QCD. We show that our ansatz captures the relevant features and is in excellent agreement with data from numerical calculations with tensor networks.
description: 7 pages, 2 figures, proceedings of the 36th Annual International Symposium on Lattice Field Theory, 22-28 July, 2018 Michigan State University, East Lansing, Michigan, USA
The fate of horizons under quantum corrections
Creators: name: Álvarez, Enrique
name: Anero, Jesús
name: Velasco-Aja, Eduardo
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We have studied a lagrangian in which the Einstein-Hilbert term is deformed by the Weyl cube operator, which is the lowest-dimension operator that is non-vanishing on shell and appears as a two-loop counterterm. There is a tension between the Schwarzschild de Sitter (SdS) spacetime and this operator, which we study in some detail.
description: 29 pages, expanded; references added