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| 2. |
- Barucca, G., et al.
(author)
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The potential of Λ and Ξ- studies with PANDA at FAIR
- 2021
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In: European Physical Journal A. - : Springer Nature. - 1434-6001 .- 1434-601X. ; 57:4
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Journal article (peer-reviewed)abstract
- The antiproton experiment PANDA at FAIR is designed to bring hadron physics to a new level in terms of scope, precision and accuracy. In this work, its unique capability for studies of hyperons is outlined. We discuss ground-state hyperons as diagnostic tools to study non-perturbative aspects of the strong interaction, and fundamental symmetries. New simulation studies have been carried out for two benchmark hyperon-antihyperon production channels: p¯ p→ Λ¯ Λ and p¯ p→ Ξ¯ +Ξ-. The results, presented in detail in this paper, show that hyperon-antihyperon pairs from these reactions can be exclusively reconstructed with high efficiency and very low background contamination. In addition, the polarisation and spin correlations have been studied, exploiting the weak, self-analysing decay of hyperons and antihyperons. Two independent approaches to the finite efficiency have been applied and evaluated: one standard multidimensional efficiency correction approach, and one efficiency independent approach. The applicability of the latter was thoroughly evaluated for all channels, beam momenta and observables. The standard method yields good results in all cases, and shows that spin observables can be studied with high precision and accuracy already in the first phase of data taking with PANDA.
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| 3. |
- De Leoz, M. L. A., et al.
(author)
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NIST Interlaboratory Study on Glycosylation Analysis of Monoclonal Antibodies: Comparison of Results from Diverse Analytical Methods
- 2020
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In: Molecular & Cellular Proteomics. - 1535-9476. ; 19:1, s. 11-30
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Journal article (peer-reviewed)abstract
- A broad-based interlaboratory study of glycosylation profiles of a reference and modified IgG antibody involving 103 reports from 76 laboratories. Glycosylation is a topic of intense current interest in the development of biopharmaceuticals because it is related to drug safety and efficacy. This work describes results of an interlaboratory study on the glycosylation of the Primary Sample (PS) of NISTmAb, a monoclonal antibody reference material. Seventy-six laboratories from industry, university, research, government, and hospital sectors in Europe, North America, Asia, and Australia submitted a total of 103 reports on glycan distributions. The principal objective of this study was to report and compare results for the full range of analytical methods presently used in the glycosylation analysis of mAbs. Therefore, participation was unrestricted, with laboratories choosing their own measurement techniques. Protein glycosylation was determined in various ways, including at the level of intact mAb, protein fragments, glycopeptides, or released glycans, using a wide variety of methods for derivatization, separation, identification, and quantification. Consequently, the diversity of results was enormous, with the number of glycan compositions identified by each laboratory ranging from 4 to 48. In total, one hundred sixteen glycan compositions were reported, of which 57 compositions could be assigned consensus abundance values. These consensus medians provide community-derived values for NISTmAb PS. Agreement with the consensus medians did not depend on the specific method or laboratory type. The study provides a view of the current state-of-the-art for biologic glycosylation measurement and suggests a clear need for harmonization of glycosylation analysis methods.
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| 4. |
- Barucca, G., et al.
(author)
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Study of excited Ξ baryons with the P¯ ANDA detector
- 2021
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In: European Physical Journal A. - : Springer Nature. - 1434-6001 .- 1434-601X. ; 57:4
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Journal article (peer-reviewed)abstract
- The study of baryon excitation spectra provides insight into the inner structure of baryons. So far, most of the world-wide efforts have been directed towards N∗ and Δ spectroscopy. Nevertheless, the study of the double and triple strange baryon spectrum provides independent information to the N∗ and Δ spectra. The future antiproton experiment P¯ANDA will provide direct access to final states containing a Ξ¯ Ξ pair, for which production cross sections up to μb are expected in p¯p reactions. With a luminosity of L= 10 31 cm- 2 s- 1 in the first phase of the experiment, the expected cross sections correspond to a production rate of ∼106events/day. With a nearly 4 π detector acceptance, P¯ANDA will thus be a hyperon factory. In this study, reactions of the type p¯p → Ξ¯ +Ξ∗ - as well as p¯p → Ξ¯ ∗ +Ξ- with various decay modes are investigated. For the exclusive reconstruction of the signal events a full decay tree fit is used, resulting in reconstruction efficiencies between 3 and 5%. This allows high statistics data to be collected within a few weeks of data taking.
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| 5. |
- Liu, F. K., et al.
(author)
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Elliptical Accretion Disk as a Model for Tidal Disruption Events
- 2021
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In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 908:2
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Journal article (peer-reviewed)abstract
- Elliptical accretion disk models for tidal disruption events (TDEs) have been recently proposed and independently developed by two groups. Although these two models are characterized by a similar geometry, their physical properties differ considerably. In this paper, we further investigate the properties of the elliptical accretion disk of the nearly uniform distribution of eccentricity within the disk plane. Our results show that the elliptical accretion disks have distinctive hydrodynamic structures and spectral energy distributions, associated with TDEs. The soft X-ray photons generated at pericenter and nearby are trapped in the disk and advected around the ellipse because of large electron scattering opacity. They are absorbed and reprocessed into emission lines and low-frequency continuum via recombination and bremsstrahlung emission. Because of the rapid increase of bound-free and free-free opacities with radius, the low-frequency continuum photons become trapped in the disk at large radius and are advected through apocenter and back to the photon-trapping radius. Elliptical accretion disks predict sub-Eddington luminosities and emit mainly at the photon-trapping radius of thousands of Schwarzschild radii with a blackbody spectrum of nearly single temperature of typically about 3 x 10(4) K. Because of the self-regulation, the photon-trapping radius expands and contracts following the rise and fall of accretion rate. The radiation temperature is nearly independent of BH mass and accretion rate and varies weakly with the stellar mass and the viscosity parameter. Our results are well consistent with the observations of optical/UV TDEs.
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| 6. |
- Ran, L., et al.
(author)
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Defect Engineering of Photocatalysts for Solar Energy Conversion
- 2020
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In: Solar RRL. - : Wiley. - 2367-198X. ; 4:4
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Journal article (peer-reviewed)abstract
- Solar energy conversion is one of the most versatile approaches for sustainable energy demands. The fundamental limitations for photocatalysis remain light absorption, charge separation, and photocatalytic (PC) performance of the catalysts. For the past few decades, defect engineering has been proven to be a promising solution for converting solar energy to chemical energy. In this regard, the recent progress of defect engineering toward solar energy conversion is summarized. Beginning with defects classification, the definition of various defects, synthesized strategies, and characterization techniques of controllable material defects are presented. The role of defect engineering on solar energy conversion is developed, extending light absorption, promoting charge separation, and facilitating stable PC reaction. The achievement of the defective photocatalysts is discussed toward versatile applications such as solar water splitting, CO2 reduction, nitrogen fixation, molecular activation, pollutants degradation, and solar cells. Finally, this Review, with regards to defect engineering, ends with the future opportunities and challenges for this exciting and emerging area for solar energy conversion.
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| 7. |
- Fu, Y., et al.
(author)
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Defect-Assisted Loading and Docking Conformations of Pharmaceuticals in Metal–Organic Frameworks
- 2021
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In: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 60:14, s. 7719-7727
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Journal article (peer-reviewed)abstract
- Understanding of drug–carrier interactions is essential for the design and application of metal–organic framework (MOF)-based drug-delivery systems, and such drug–carrier interactions can be fundamentally different for MOFs with or without defects. Herein, we reveal that the defects in MOFs play a key role in the loading of many pharmaceuticals with phosphate or phosphonate groups. The host–guest interaction is dominated by the Coulombic attraction between phosphate/phosphonate groups and defect sites, and it strongly enhances the loading capacity. For similar molecules without a phosphate/phosphonate group or for MOFs without defects, the loading capacity is greatly reduced. We employed solid-state NMR spectroscopy and molecular simulations to elucidate the drug–carrier interaction mechanisms. Through a synergistic combination of experimental and theoretical analyses, the docking conformations of pharmaceuticals at the defects were revealed.
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| 8. |
- Wu, Y., et al.
(author)
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Rational Design of Nanocatalysts with Nonmetal Species Modification for Electrochemical CO2 Reduction
- 2020
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In: Advanced Energy Materials. - : Wiley-VCH Verlag. - 1614-6832 .- 1614-6840. ; 10:29
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Journal article (peer-reviewed)abstract
- Converting CO2 to valuable carbonaceous fuels and chemicals via electrochemical CO2 reduction by using renewable energy sources is considered to be a scalable strategy with substantial environmental and economic benefits. One of the challenges in this field is to develop nanocatalysts with superior electrocatalytic activity and selectivity for targeted products. Nonmetal species modification of nanocatalysts is of great significance for the construction of distinctive active sites to overcome the kinetic limitations of CO2 reduction. These types of modification enable the efficient control of the selectivity and significantly decrease the reaction overpotential. Herein, a comprehensive review of the recent progress of nonmetal species modification of nanocatalysts for electrochemical CO2 reduction is presented. After discussing some fundamental parameters and the basic principles of CO2 reduction, including possible reaction pathways in light of theoretical modeling and experiments, the identification of active sites and elucidation of reaction mechanisms are emphasized for unraveling the role of nonmetal species modification, such as heteroatom incorporation, organic molecule decoration, electrolyte engineering, and single-atom engineering. In the final section, future challenges and constructive perspectives are provided, facilitating the accelerated advancement of mechanism research and practical applications of green carbon cycling.
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| 9. |
- Zhang, B., et al.
(author)
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Metal-Organic-Framework-Derived Bismuth Nanosheets for Electrochemical and Solar-Driven Electrochemical CO2 Reduction to Formate
- 2021
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In: ChemElectroChem. - : Wiley. - 2196-0216. ; 8:5, s. 880-886
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Journal article (peer-reviewed)abstract
- Electrochemical CO2 reduction is a promising way to achieve CO2 fixation and energy storage. However, it is a challenge to develop the potential electrocatalysts with excellent performance and selectivity. Herein, bismuth nanosheet arrays (Bi/CC-17) are prepared through an in situ electrochemical transformation strategy by use of Bi-based metal organic frameworks (MOFs) as the precursors, which are then attached on carbon cloth. The as-synthesized Bi/CC-17 nanosheet arrays achieve considerable partial current density of 45 mA cm−2 and remarkably high faradic efficiency of 98 % at the potential of −1.1 V versus RHE for the conversion of CO2 to formate, outperforming most previously reported electrocatalysts. In particular, the solar-driven In2O3/In2S3∥Bi two-electrode system with a In2O3/In2S3-based photoanode and typical Bi-based cathode achieves high faradaic efficiencies of ≥90 % for HCOOH formation, from −0.6 to −1.6 V versus the counter electrode (vs. CE). This work paves an avenue to develop MOF-derived electrocatalysts for sustainable conversion of CO2 into valuable chemicals.
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| 10. |
- Law, Chi Yan, 1990, et al.
(author)
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The links between magnetic fields and filamentary clouds - III. Field-regulated mass cumulative functions
- 2020
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In: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 498:1, s. 850-858
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Journal article (peer-reviewed)abstract
- During the past decade, the dynamical importance of magnetic fields in molecular clouds has been increasingly recognized, as observational evidence has accumulated. However, how a magnetic field affects star formation is still unclear. Typical star formation models still treat a magnetic fields as an isotropic pressure, ignoring the fundamental property of dynamically important magnetic fields: their direction. This study builds on our previous work, which demonstrated how the mean magnetic field orientation relative to the global cloud elongation can affect cloud fragmentation. After the linear mass distribution reported earlier, we show here that the mass cumulative function (MCF) of a cloud is also regulated by the field orientation. A cloud elongated closer to the field direction tends to have a shallower MCF: in other words, a higher portion of the gas is at high density. The evidence is consistent with our understanding of the bimodal star formation efficiency discovered earlier, which is also correlated with the field orientation.
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