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https://www.readbyqxmd.com/read/28211708/direct-observation-of-spatiotemporal-dynamics-of-short-electron-bunches-in-storage-rings
#1
C Evain, E Roussel, M Le Parquier, C Szwaj, M-A Tordeux, J-B Brubach, L Manceron, P Roy, S Bielawski
In recent synchrotron radiation facilities, the use of short (picosecond) electron bunches is a powerful method for producing giant pulses of terahertz coherent synchrotron radiation. Here we report on the first direct observation of these pulse shapes with a few picoseconds resolution, and of their dynamics over a long time. We thus confirm in a very direct way the theories predicting an interplay between two physical processes. Below a critical bunch charge, we observe a train of identical THz pulses (a broadband Terahertz comb) stemming from the shortness of the electron bunches...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28208578/role-of-cortico-cancellous-heterologous-bone-in-human-periodontal-ligament-stem-cell-xeno-free-culture-studied-by-synchrotron-radiation-phase-contrast-microtomography
#2
Serena Mazzoni, Sara Mohammadi, Giuliana Tromba, Francesca Diomede, Adriano Piattelli, Oriana Trubiani, Alessandra Giuliani
This study was designed to quantitatively demonstrate via three-dimensional (3D) images, through the Synchrotron Radiation Phase-Contrast Microtomography (SR-PhC-MicroCT), the osteoinductive properties of a cortico-cancellous scaffold (Osteobiol Dual Block-DB) cultured with human Periodontal Ligament Stem Cells (hPDLSCs) in xeno-free media. In vitro cultures of hPDLSCs, obtained from alveolar crest and horizontal fibers of the periodontal ligament, were seeded onto DB scaffolds and cultured in xeno-free media for three weeks...
February 10, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28202732/atomic-structure-of-granulin-determined-from-native-nanocrystalline-granulovirus-using-an-x-ray-free-electron-laser
#3
Cornelius Gati, Dominik Oberthuer, Oleksandr Yefanov, Richard D Bunker, Francesco Stellato, Elaine Chiu, Shin-Mei Yeh, Andrew Aquila, Shibom Basu, Richard Bean, Kenneth R Beyerlein, Sabine Botha, Sébastien Boutet, Daniel P DePonte, R Bruce Doak, Raimund Fromme, Lorenzo Galli, Ingo Grotjohann, Daniel R James, Christopher Kupitz, Lukas Lomb, Marc Messerschmidt, Karol Nass, Kimberly Rendek, Robert L Shoeman, Dingjie Wang, Uwe Weierstall, Thomas A White, Garth J Williams, Nadia A Zatsepin, Petra Fromme, John C H Spence, Kenneth N Goldie, Johannes A Jehle, Peter Metcalf, Anton Barty, Henry N Chapman
To understand how molecules function in biological systems, new methods are required to obtain atomic resolution structures from biological material under physiological conditions. Intense femtosecond-duration pulses from X-ray free-electron lasers (XFELs) can outrun most damage processes, vastly increasing the tolerable dose before the specimen is destroyed. This in turn allows structure determination from crystals much smaller and more radiation sensitive than previously considered possible, allowing data collection from room temperature structures and avoiding structural changes due to cooling...
February 15, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28197565/electronic-spectroscopy-of-ethyl-bromide-probed-by-vuv-photoabsorption-and-quantum-chemical-calculations
#4
Aparna Shastri, Param Jeet Singh, Sunanda Krishnakumar, Asim Kumar Das, B N Raja Sekhar
The electronically excited states of ethyl bromide and its deuterated isotopologue (C2H5Br and C2D5Br) are studied using synchrotron radiation based photoabsorption spectroscopy in the wavenumber region 50 000-86 000 cm(-1). A detailed spectral analysis supported by quantum chemical calculations is presented. A complex Rydberg series structure comprising of nsa1, npa1, npe, nda1 and nde series, converging to each of the two spin-orbit split components of the first ionization potential ((2)E3/2 and (2)E1/2) is observed for both the isotopologues...
February 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28194968/pedot-pss-as-solid-contact-for-ion-selective-electrodes-the-influence-of-the-pedot-pss-film-thickness-on-the-equilibration-times
#5
Marcin Guzinski, Jennifer Marie Jarvis, Felio Perez, Bradford D Pendley, Erno Lindner, Roland de Marco, Gaston A Crespo, Robert G Acres, Raymart Walker, Josiah Luke Bishop
To understand the rate determining processes during the equilibration of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate-based (PEDOT(PSS)-based) solid contact (SC) ion-selective electrodes (ISEs), the surfaces of Pt, Au, and GC electrodes were coated with 0.1, 1.0, 2.0 and 4.0μm thick galvanostatically deposited PEDOT(PSS) films. Next, potential vs. time transients were recorded with these electrodes, with and without an additional potassium ion-selective membrane (ISM) coating, following their first contact with 0...
February 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28194309/trace-elements-during-primordial-plexiform-network-formation-in-human-cerebral-organoids
#6
Rafaela C Sartore, Simone C Cardoso, Yury V M Lages, Julia M Paraguassu, Mariana P Stelling, Rodrigo F Madeiro da Costa, Marilia Z Guimaraes, Carlos A Pérez, Stevens K Rehen
Systematic studies of micronutrients during brain formation are hindered by restrictions to animal models and adult post-mortem tissues. Recently, advances in stem cell biology have enabled recapitulation of the early stages of human telencephalon development in vitro. In the present work, we analyzed cerebral organoids derived from human pluripotent stem cells by synchrotron radiation X-ray fluorescence in order to measure biologically valuable micronutrients incorporated and distributed into the exogenously developing brain...
2017: PeerJ
https://www.readbyqxmd.com/read/28192906/coupling-high-throughput-microfluidics-and-small-angle-x-ray-scattering-to-study-protein-crystallization-from-solution
#7
Nhat Pham, Dimitri Radajewski, Adam Round, Martha Brennich, Petra Pernot, Béatrice Biscans, Françoise Bonneté, Sébastien Teychené
In this work, we propose the combination of small-angle X-ray scattering (SAXS) and high throughput, droplet based microfluidics as a powerful tool to investigate macromolecular interactions, directly related to protein solubility. For this purpose, a robust and low cost microfluidic platform was fabricated for achieving the mixing of proteins, crystallization reagents, and buffer in nanoliter volumes and the subsequent generation of nanodroplets by means of a two phase flow. The protein samples are compartmentalized inside droplets, each one acting as an isolated microreactor...
February 8, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28192171/a-new-light-on-alkaptonuria-a-fourier-transform-infrared-microscopy-ftirm-and-low-energy-x-ray-fluorescence-lexrf-microscopy-correlative-study-on-a-rare-disease
#8
Elisa Mitri, Lia Millucci, Lucia Merolle, Giulia Bernardini, Lisa Vaccari, Alessandra Gianoncelli, Annalisa Santucci
BACKGROUND: Alkaptonuria (AKU) is an ultra-rare disease associated to the lack of an enzyme involved in tyrosine catabolism. This deficiency results in the accumulation of homogentisic acid (HGA) in the form of ochronotic pigment in joint cartilage, leading to a severe arthropathy. Secondary amyloidosis has been also unequivocally assessed as a comorbidity of AKU arthropathy. Composition of ochronotic pigment and how it is structurally related to amyloid is still unknown. METHODS: We exploited Synchrotron Radiation Infrared and X-Ray Fluorescence microscopies in combination with conventional bio-assays and analytical tools to characterize chemical composition and morphology of AKU cartilage...
February 9, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28191967/evaluation-of-re-oxidation-thresholds-for-%C3%AE-al2o3-supported-cobalt-catalysts-under-fischer-tropsch-synthesis-conditions
#9
Nikolaos E Tsakoumis, John C Walmsley, Magnus Rønning, Wouter van Beek, Erling Rytter, Anders Holmen
Size dependent phenomena at the nanoscale influence many applications, notably in the science of heterogeneous catalysis. In cobalt based Fischer - Tropsch synthesis, the size of Co nanoparticles dictates to a high degree catalysts performance in terms of activity, selectivity and stability. Here, a highly dispersed Re/Co/γ-Al2O3 catalyst with high Co surface area per gram of catalyst was exposed to industrially relevant Fischer-Tropsch synthesis conditions and monitored in situ by synchrotron X-ray radiation...
February 13, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28190992/new-synchrotron-powder-diffraction-facility-for-long-duration-experiments
#10
Claire A Murray, Jonathan Potter, Sarah J Day, Annabelle R Baker, Stephen P Thompson, Jon Kelly, Christopher G Morris, Sihai Yang, Chiu C Tang
A new synchrotron X-ray powder diffraction instrument has been built and commissioned for long-duration experiments on beamline I11 at Diamond Light Source. The concept is unique, with design features to house multiple experiments running in parallel, in particular with specific stages for sample environments to study slow kinetic systems or processes. The instrument benefits from a high-brightness X-ray beam and a large area detector. Diffraction data from the commissioning work have shown that the objectives and criteria are met...
February 1, 2017: Journal of Applied Crystallography
https://www.readbyqxmd.com/read/28187077/comparison-of-synchrotron-radiation-based-propagation-phase-contrast-imaging-and-conventional-micro-computed-tomography-for-assessing-intervertebral-discs-and-endplates-in-a-murine-model
#11
Jianzhong Hu, Shuangfei Ni, Yong Cao, Xiaokai Wang, Shenghui Liao, Hongbin Lu
STUDY DESIGN: The synchrotron radiation based micro-CT (SRμCT) and micro-CT (μCT) were applied to comparatively assess the intervertebral disc (IVD) and endplate (EP). OBJECTIVE: To explore a new approach to evaluate the detailed structure of the IVD and EP during maturation and aging in a murine model. SUMMARY OF BACKGROUND DATA: To date, methods to observe the morphological changes in the IVD and EP from rodent have been relatively limited...
February 9, 2017: Spine
https://www.readbyqxmd.com/read/28178820/preface-special-topic-on-atomic-and-molecular-layer-processing-deposition-patterning-and-etching
#12
James R Engstrom, Andrew C Kummel
Thin film processing technologies that promise atomic and molecular scale control have received increasing interest in the past several years, as traditional methods for fabrication begin to reach their fundamental limits. Many of these technologies involve at their heart phenomena occurring at or near surfaces, including adsorption, gas-surface reactions, diffusion, desorption, and re-organization of near-surface layers. Moreover many of these phenomena involve not just reactions occurring under conditions of local thermodynamic equilibrium but also the action of energetic species including electrons, ions, and hyperthermal neutrals...
February 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28178818/who-s-on-first-tracking-in-real-time-the-growth-of-multiple-crystalline-phases-of-an-organic-semiconductor-tetracene-on-sio2
#13
R K Nahm, J R Engstrom
We have examined the effect of growth rate on the evolution of two polymorphs of thin films of tetracene on SiO2 using synchrotron X-ray radiation and molecular beam techniques. Ex situ X-ray reflectivity shows that tetracene forms two phases on SiO2: a thin-film phase and a bulk phase. We have used in situ, real-time grazing incidence diffraction during growth to reveal the nature of growth concerning these two phases. We observe that there is initially growth of only the thin-film phase, up to a thickness of several monolayers...
February 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28178293/%C3%AE-ct-of-ex-vivo-stained-mouse-hearts-and-embryos-enables-a-precise-match-between-3d-virtual-histology-classical-histology-and-immunochemistry
#14
Christian Dullin, Roser Ufartes, Emanuel Larsson, Sabine Martin, Marcio Lazzarini, Giuliana Tromba, Jeannine Missbach-Guentner, Diana Pinkert-Leetsch, Dörthe M Katschinski, Frauke Alves
The small size of the adult and developing mouse heart poses a great challenge for imaging in preclinical research. The aim of the study was to establish a phosphotungstic acid (PTA) ex-vivo staining approach that efficiently enhances the x-ray attenuation of soft-tissue to allow high resolution 3D visualization of mouse hearts by synchrotron radiation based μCT (SRμCT) and classical μCT. We demonstrate that SRμCT of PTA stained mouse hearts ex-vivo allows imaging of the cardiac atrium, ventricles, myocardium especially its fibre structure and vessel walls in great detail and furthermore enables the depiction of growth and anatomical changes during distinct developmental stages of hearts in mouse embryos...
2017: PloS One
https://www.readbyqxmd.com/read/28177544/hso2-formation-from-ion-molecule-reactions-of-so2-with-water-and-methane-two-fast-reactions-with-reverse-temperature-dependent-kinetic-trend
#15
Antonella Cartoni, Daniele Catone, Paola Bolognesi, Mauro Satta, Pal Markus, Lorenzo Avaldi
In this work an experimental and theoretical study on the formation of HSO2+ ion from the SO2.+ + CH4 and SO2.+ + H2O ion-molecule reactions at different temperatures is reported. Tunable synchrotron radiation has been used to produce the SO2.+ ion in excited ro-vibrational levels of the ionic ground state X2A1 and mass spectrometry has been employed to identify the product ions. Calculations in the frame of the density functional theory and variational transtition state theory have been combined to explore the dynamics of the reactions...
February 8, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28177221/highly-selective-and-repeatable-surface-enhanced-resonance-raman-scattering-detection-for-epinephrine-in-serum-based-on-interface-self-assembled-2d-nanoparticles-arrays
#16
Binbin Zhou, Xiaoyun Li, Xianghu Tang, Pan Li, LiangBao Yang, Jinhuai Liu
Target analyte detection in complex system with high selectivity and repeatability is crucial to analytical technology and science. Here we present a two-dimensional (2D) surface-enhanced resonance Raman scattering (SERRS) platform, which takes advantage of self-assembled of Au nanoparticles (Au NPs) arrays at cyclohexane/water interface, for detecting trace Epinephrine (EP) in the serum. To realize sensitive and selective detection of EP in complex system, Au NPs is modified with -nitriloacetic acid and Fe(NO3)3 to form the Au NP-(Fe-NTA) sensor, as consequence, EP can be rapidly captured by sen-sor on the surface of Au NPs, then delivered at cyclohexane/water interface...
February 8, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28170434/the-internal-cranial-anatomy-of-romundina-stellina-%C3%A3-rvig-1975-vertebrata-placodermi-acanthothoraci-and-the-origin-of-jawed-vertebrates-anatomical-atlas-of-a-primitive-gnathostome
#17
Vincent Dupret, Sophie Sanchez, Daniel Goujet, Per Erik Ahlberg
Placoderms are considered as the first jawed vertebrates and constitute a paraphyletic group in the stem-gnathostome grade. The acanthothoracid placoderms are among the phylogenetically most basal and morphologically primitive gnathostomes, but their neurocranial anatomy is poorly understood. Here we present a near-complete three-dimensional skull of Romundina stellina, a small Early Devonian acanthothoracid from the Canadian Arctic Archipelago, scanned with propagation phase contrast microtomography at a 7...
2017: PloS One
https://www.readbyqxmd.com/read/28170101/torsion-estimation-of-particle-paths-through-porous-media-observed-by-in-situ-time-resolved-microtomography
#18
C Blankenburg, A Rack, C Daul, J Ohser
The torsion distribution of cell paths in two-phase flow of a cell suspension through a porous medium is an important quantity for chromatographic processes. It can be estimated from cell tracking in sequences of three-dimensional images of a suspension pumped through the medium, where the images are acquired by in-situ time-resolved microtomography using synchrotron radiation and inline phase contrast modus. This contribution presents a new method for estimating path torsion from discrete positions, where the estimation is based on an appropriate discretization of the differential-geometric formula of the torsion of a space curve...
February 7, 2017: Journal of Microscopy
https://www.readbyqxmd.com/read/28165880/complete-transformation-of-zno-and-cuo-nanoparticles-in-culture-medium-and-lymphocyte-cells-during-toxicity-testing
#19
Angela Ivask, Kirk G Scheckel, Pankaj Kapruwan, Vicki Stone, Hong Yin, Nicolas H Voelcker, Enzo Lombi
Here, we present evidence on complete transformation of ZnO and CuO nanoparticles, which are among the most heavily studied metal oxide particles, during 24 h in vitro toxicological testing with human T-lymphocytes. Synchrotron radiation-based X-ray absorption near edge structure (XANES) spectroscopy results revealed that Zn speciation profiles of 30 nm and 80 nm ZnO nanoparticles, and ZnSO4- exposed cells were almost identical with the prevailing species being Zn-cysteine. This suggests that ZnO nanoparticles are rapidly transformed during a standard in vitro toxicological assay, and are sequestered intracellularly, analogously to soluble Zn...
February 6, 2017: Nanotoxicology
https://www.readbyqxmd.com/read/28152311/synchrotron-photoionization-investigation-of-the-oxidation-of-ethyl-tert-butyl-ether
#20
Matthew Winfough, Rong Yao, Martin Y Ng, Katherine J Catani, Giovanni Meloni
The oxidation of ethyl tert-butyl ether (ETBE), a widely used fuel oxygenated additive, is investigated using Cl atoms as initiators in the presence of oxygen. The reaction is carried out at 293, 550, and 700 K. Reaction products are probed by a multiplexed chemical kinetics photoionization mass spectrometer coupled with the synchrotron radiation produced at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory. Products are identified based on mass-to-charge ratio, ionization energies, and shape of photoionization spectra...
February 2, 2017: Journal of Physical Chemistry. A
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