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Quantum Beam Sci., Volume 3, Issue 4 (December 2019) – 7 articles

Cover Story (view full-size image): A new cooled astronomy CMOS camera was used to build a compact low-priced but high-quality imaging detector for neutrons, X-rays or visible light, relying on external shielding, which can be fully integrated into a professional setup. However, since precision is achieved by software processing, a cheap motion control system based on a Raspberry Pi, a stepper motor with an attached gear box, and a small printer translation stage were sufficient to create a mobile computed tomography evaluation system that can, in the absence of neutron or X-ray sources, perform tomography even with visible light. View this paper.

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17 pages, 9846 KiB

Open AccessArticle

In-Situ Characterization by High-Energy X-ray Diffraction of the Phase Transformations Leading to Transformation-Induced Plasticity-Aided Bainitic Steel

by Zélie Tournoud, Frédéric De Geuser, Gilles Renou, Didier Huin, Patricia Donnadieu and Alexis Deschamps

Quantum Beam Sci. 2019, 3(4), 25; https://doi.org/10.3390/qubs3040025 - 12 Dec 2019

Cited by 2 | Viewed by 2774

Abstract

The phase transformations occurring during the heat treatments leading to transformation-induced plasticity (TRIP)-aided bainitic steel have been investigated in-situ by high-energy X-ray diffraction (HEXRD) conducted with synchrotron light at 90 keV. Direct microstructure characterization has been performed by electron microscopy using electron backscatter diffraction and orientation and phase mapping in a transmission electron microscope. HEXRD data allow the quantification of the evolution of the austenite phase fraction with the heat treatments, as well as its carbon content and the fraction of carbides, from the lattice parameter evolution. It is shown that different combinations of austenite fraction and carbon content can be reached by adjusting the heat treatment temperature. Full article

(This article belongs to the Special Issue Microstructural and Phase Transformations in Materials)

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14 pages, 2095 KiB

Open AccessArticle

Ab Initio Molecular Dynamics Simulations to Interpret the Molecular Fragmentation Induced in Deoxyribose by Synchrotron Soft X-Rays

by Marie-Anne Hervé du Penhoat, Anis Hamila, Marie-Pierre Gaigeot, Rodolphe Vuilleumier, Kentaro Fujii, Akinari Yokoya and Marie-Françoise Politis

Quantum Beam Sci. 2019, 3(4), 24; https://doi.org/10.3390/qubs3040024 - 10 Dec 2019

Cited by 2 | Viewed by 2532

Abstract

It has been suggested that core ionization in DNA atoms could induce complex, irreparable damage. Synchrotron soft X-rays have been used to probe the damage induced by such events in thin films of DNA components. In a complementary approach, we investigate the fragmentation dynamics following a carbon or oxygen K-shell ionization in 2-deoxy-D-ribose (DR), a major component in the DNA chain. Core ionization of the sugars hydration layer is also studied. To that aim, we use state-of-the-art ab initio Density Functional Theory-based Molecular Dynamics (MD) simulations. The ultrafast dissociation dynamics of the core ionized molecule, prior Auger decay, is modeled for about 10 fs. We show that the core-ionization of oxygen atoms within DR or its hydration layer may induce proton transfers towards nearby molecules, before Auger decay. In a second step, we model an Auger effect occurring either at the beginning or at the end of the core–hole dynamics. Two electrons are removed from the deepest valence molecular orbitals localized on the initially core-ionized oxygen atom (O*), and this electronic state is propagated by means of Ehrenfest MD. We show an ultrafast dissociation of the DR²⁺ molecule C-O* bonds, which, in most cases, seems independent of the time at which Auger decay occurs. Full article

(This article belongs to the Special Issue Advanced Synchrotron Radiation as a Quantum Tool for Exploring Deep Life Sciences)

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11 pages, 1203 KiB

Open AccessReview

Structural Alterations of Histone Proteins in DNA-Damaged Cells Revealed by Synchrotron Radiation Circular Dichroism Spectroscopy: A New Piece of the DNA-Damage-Response Puzzle

by Yudai Izumi

Quantum Beam Sci. 2019, 3(4), 23; https://doi.org/10.3390/qubs3040023 - 06 Dec 2019

Cited by 1 | Viewed by 2826

Abstract

Double-strand breaks of DNA may lead to discontinuous DNA and consequent loss of genetic information, which may result in mutations or, ultimately, carcinogenesis. To avoid such potentially serious situations, cells have evolved efficient DNA damage repair systems. It is thought that DNA-repair processes involve drastic alterations of chromatin and histone structures, but detection of these altered structures in DNA-damaged cells remains rare in the literature. Recently, synchrotron radiation circular dichroism (SRCD) spectroscopy, which can provide secondary structural information of proteins in solution, has identified structural alterations of histone proteins induced by DNA damage responses. In this review, these results and experimental procedures are discussed with the aim of facilitating further studies of the chromatin remodeling and DNA damage repair pathways using SRCD spectroscopy. Full article

(This article belongs to the Special Issue Advanced Synchrotron Radiation as a Quantum Tool for Exploring Deep Life Sciences)

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2 pages, 173 KiB

Open AccessEditorial

Quantum Beams for New Aspects in Magnetic Materials and Magnetism

by Robert Georgii and Klaus-Dieter Liss

Quantum Beam Sci. 2019, 3(4), 22; https://doi.org/10.3390/qubs3040022 - 25 Nov 2019

Viewed by 1957

Abstract

Welcome to the special issue of Quantum Beam Science on “Magnetic Materials and Magnetism” [...] Full article

(This article belongs to the Special Issue Magnetic Materials and Magnetism)

13 pages, 7003 KiB

Open AccessArticle

An Affordable Image Detector and a Low-Cost Evaluation System for Computed Tomography Using Neutrons, X-rays, or Visible Light

by Burkhard Schillinger

Quantum Beam Sci. 2019, 3(4), 21; https://doi.org/10.3390/qubs3040021 - 08 Nov 2019

Cited by 8 | Viewed by 3311

Abstract

Neutron computed tomography (nCT) has been established at many major neutron sources worldwide, using high-end equipment requiring major investment and development. Many older and smaller reactors would also be capable of doing nCT, but cannot afford the investment before feasibility is proven. We have developed a compact low-cost but high-quality detection system using a new cooled CMOS camera that can either be fully integrated into a sophisticated setup, or used with a rudimentary CT control and motion system to quickly evaluate feasibility of neutron CT at a given beam line facility. Exchanging the scintillation screen makes it feasible for X-rays as well, even for visible light (and transparent samples) using a matte screen. The control system uses a hack to combine motion control with existing imaging software so it can be used to test several dozen different cameras without writing specific drivers. Freeware software can do reconstruction and 3D imaging. Full article

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10 pages, 3595 KiB

Open AccessFeature PaperArticle

Multi-Scale Microstructure Investigation for a PM_2.5 Air-Filter Efficiency Study of Non-Woven Polypropylene

by Tu-Ngoc Lam, Chen-Hsien Wu, Sheng-Hsiu Huang, Wen-Ching Ko, Yu-Lih Huang, Chia-Yin Ma, Chun-Chieh Wang and E-Wen Huang

Quantum Beam Sci. 2019, 3(4), 20; https://doi.org/10.3390/qubs3040020 - 28 Oct 2019

Cited by 17 | Viewed by 7248

Abstract

A N95 face-piece respirator and a 3M air filter composed of non-woven polypropylene filter material were investigated for their multi-scale microstructure and resulting filtration performance. Filtration mechanisms of each system are found and quantified. Both media showed a gradually decrease of the most penetrating particle size with respect to an increase in face velocity or surface charge density. Increasing the face velocity and porosity dramatically degraded the collection efficiency in the 3M filter rather than in the N95 system. We exploited three-dimensional X-ray tomography to characterize the morphological and geometrical properties of the fiber arrangement and deposition of aerosol on the fiber surface. Tuning the most predominant material parameters to achieve a precedence in lower pressure drop or higher collection efficiency in a specifically captured particle size range is of great requisite to a peculiar application of the filter media. Full article

(This article belongs to the Special Issue Asia-Oceania Neutron and Advanced Photon Source for Industrial Applications)

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