keyword
MENU ▼
Read by QxMD icon Read
search

Synchrotron

keyword
https://www.readbyqxmd.com/read/28211724/experimental-evidence-for-static-charge-density-waves-in-iron-oxypnictides
#1
A Martinelli, P Manfrinetti, A Provino, A Genovese, F Caglieris, G Lamura, C Ritter, M Putti
In this Letter we report high-resolution synchrotron x-ray powder diffraction and transmission electron microscope analysis of Mn-substituted LaFeAsO samples, demonstrating that a static incommensurate modulated structure develops across the low-temperature orthorhombic phase, whose modulation wave vector depends on the Mn content. The incommensurate structural distortion is likely originating from a charge-density-wave instability, a periodic modulation of the density of conduction electrons associated with a modulation of the atomic positions...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28211708/direct-observation-of-spatiotemporal-dynamics-of-short-electron-bunches-in-storage-rings
#2
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/28210739/retinal-oxidative-stress-at-the-onset-of-diabetes-determined-by-synchrotron-ftir-widefield-imaging-towards-diabetes-pathogenesis
#3
Ebrahim Aboualizadeh, Mahsa Ranji, Christine M Sorenson, Reyhaneh Sepehr, Nader Sheibani, Carol J Hirschmugl
Diabetic retinopathy is a microvascular complication of diabetes that can lead to blindness. In the present study, we aimed to determine the nature of diabetes-induced, highly localized biochemical changes in the neuroretina at the onset of diabetes. High-resolution synchrotron Fourier transform infrared (s-FTIR) wide field microscopy coupled with multivariate analysis (PCA-LDA) was employed to identify biomarkers of diabetic retinopathy with spatial resolution at the cellular level. We compared the retinal tissue prepared from 6-week-old Ins2(Akita/+) heterozygous (Akita/+, N = 6; a model of diabetes) male mice with the wild-type (control, N = 6) mice...
February 17, 2017: Analyst
https://www.readbyqxmd.com/read/28209631/hdpscs-fabricate-a-vascularised-woven-bone-tissue-a-new-tool-in-bone-tissue-engineering
#4
Francesca Paino, Marcella La Noce, Alessandra Giuliani, Alfredo De Rosa, Serena Mazzoni, Luigi Laino, Evzen Amler, Gianpaolo Papaccio, Vincenzo Desiderio, Virginia Tirino
Human dental pulp stem cells (hDPSCs) are mesenchymal stem cells successfully used in human bone tissue engineering. To better establish if these cells can lead to a bone tissue ready to be grafted, we checked DPSCs for their osteogenic and angiogenic differentiation capabilities with the specific aim to obtain a new tool for bone transplantation. Therefore, hDPSCs were specifically selected from the stromal-vascular dental pulp fraction, using appropriate markers and cultured. Growth curves, expression of bone-related markers, calcification, angiogenesis as well as in vivo transplantation assay were performed...
February 16, 2017: Clinical Science (1979-)
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
#5
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/28207770/embarras-de-richesses-it-is-not-good-to-be-too-anomalous-accurate-structure-of-selenourea-a-chiral-crystal-of-planar-molecules
#6
Zhipu Luo, Zbigniew Dauter
Selenourea, SeC(NH2)2, recently found an application as a derivatization reagent providing a significant anomalous diffraction signal used for phasing macromolecular crystal structures. The crystal structure of selenourea itself was solved about 50 years ago, from data recorded on films and evaluated by eye and refined to R = 0.15 with errors of bond lengths and angles about 0.1 Å and 6°. In the current work this structure is re-evaluated on the basis of synchrotron data and refined to R1 = 0.021 with bond and angle errors about 0...
2017: PloS One
https://www.readbyqxmd.com/read/28205587/nickel-biopathways-in-tropical-nickel-hyperaccumulating-trees-from-sabah-malaysia
#7
Antony van der Ent, Damien L Callahan, Barry N Noller, Jolanta Mesjasz-Przybylowicz, Wojciech J Przybylowicz, Alban Barnabas, Hugh H Harris
The extraordinary level of accumulation of nickel (Ni) in hyperaccumulator plants is a consequence of specific metal sequestering and transport mechanisms, and knowledge of these processes is critical for advancing an understanding of transition element metabolic regulation in these plants. The Ni biopathways were elucidated in three plant species, Phyllanthus balgooyi, Phyllanthus securinegioides (Phyllanthaceae) and Rinorea bengalensis (Violaceae), that occur in Sabah (Malaysia) on the Island of Borneo. This study showed that Ni is mainly concentrated in the phloem in roots and stems (up to 16...
February 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28202732/atomic-structure-of-granulin-determined-from-native-nanocrystalline-granulovirus-using-an-x-ray-free-electron-laser
#8
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/28202241/geochemical-and-mineralogical-characterization-of-sulfur-and-iron-in-coal-waste-rock-elk-valley-british-columbia-canada
#9
Joseph Essilfie-Dughan, M Jim Hendry, James J Dynes, Yongfeng Hu, Ashis Biswas, S Lee Barbour, S Day
Exposure of coal waste rock to atmospheric oxygen can result in the oxidation of sulfide minerals and the release of sulfate (SO4(2-)) and associated trace elements (e.g., Se, As, Cd, and Zn) to groundwaters and surface waters. Similarly, reduced iron minerals such as siderite, ankerite, and the sulfide, pyrite, present in the waste rock can also undergo oxidation, resulting in the formation of iron oxyhydroxides that can adsorb trace elements released from the oxidation of the sulfide minerals. Characterization and quantification of the distribution of sulfide and iron minerals, their oxidation products, as well as leaching rates are critical to assessing present-day and future impacts of SO4(2-) and associated trace elements on receiving waters...
February 12, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28198491/thermal-expansion-in-baruo3-perovskites-an-unusual-case-of-bond-strengthening-at-high-temperatures
#10
Paula Kayser, Sean Injac, Brendan J Kennedy, Andre L Menezes de Oliveira, Yuichi Shirako, Masashi Hasegawa
The temperature dependences of the structures of three polytypes of BaRuO3 have been investigated between room temperature and 1000 °C using high resolution synchrotron X-ray diffraction. The structural studies reveal a systematic decrease of the Ru-Ru distance as the pressure required to prepare the polytype increases. The O-O distance across the shared face increases as the Ru-Ru separation decreases. The 9R and 4H polytypes undergo unexceptional changes with increasing temperature. In 6H-BaRuO3 there is an apparent increase in the Ru-Ru interaction at around 650 °C and a concurrent reduction in the O-O distance, indicating an anomalous strengthening of the Ru-Ru interactions upon heating...
February 15, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28197589/an-unusual-nitride-network-of-aluminum-centered-octahedra-and-phosphorus-centered-tetrahedra-and-structure-determination-from-microcrystalline-samples
#11
Lukas Neudert, Frank Heinke, Thomas Bräuniger, Florian J Pucher, Gavin B Vaughan, Oliver Oeckler, Wolfgang Schnick
A new imidooxonitridophosphate AlP6O3x(NH)3-3xN9 with x ≈ 0.33 was synthesized under high-pressure high-temperature conditions. The crystal structure determination of the microcrystalline product involved a combination of electron microscopy, synchrotron X-ray diffraction and solid-state NMR. In the solid there are discrete AlN6 octahedra that interconnect imidophosphate layers. The network topology is unprecedented but is related to other nitride structures.
February 15, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28197565/electronic-spectroscopy-of-ethyl-bromide-probed-by-vuv-photoabsorption-and-quantum-chemical-calculations
#12
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/28195712/synthetic-approach-for-mn-fe-2-si-p-magnetocaloric-materials-purity-structural-magnetic-and-magnetocaloric-properties
#13
Allan He, Volodymyr Svitlyk, Yurij Mozharivskyj
A conventional solid-state approach has been developed for the synthesis of phase-pure magnetocaloric Mn2-xFexSi0.5P0.5 materials (x = 0.6, 0.7, 0.8, 0.9). Annealing at high temperatures followed by dwelling at lower temperatures is essential to obtain pure samples with x = 0.7, 0.8, and 0.9. Structural features of the samples with x = 0.6 and 0.9 were analyzed as a function of temperature via synchrotron powder diffraction. The Curie temperature, temperature hysteresis, and magnetic entropy change were established from the magnetic measurements...
February 14, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28195490/investigation-of-spatial-heterogeneity-of-salt-disproportionation-in-tablets-by-synchrotron-x-ray-diffractometry
#14
Sampada A Koranne, Ramprakash Govindarajan, Raj Suryanarayanan
Tablets which were binary mixtures of pioglitazone hydrochloride (PioHCl) with magnesium stearate (MgSt), croscarmellose sodium (CCS), microcrystalline cellulose or lactose monohydrate were prepared. Two sets of experiments, using intact tablets, were performed. (i) Tablets containing PioHCl (90% w/w) and MgSt were exposed to 25 or 40 °C and 75% RH in a custom built temperature/humidity chamber. In situ spatio-temporal mapping of disproportionation was performed by transmission mode synchrotron X-ray diffractometry (SXRD; Argonne National Labs)...
February 14, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28195328/visualization-of-xylem-embolism-by-x-ray-microtomography-a-direct-test-against-hydraulic-measurements
#15
Markus Nolf, Rosana Lopez, Jennifer M R Peters, Richard J Flavel, Leah S Koloadin, Iain M Young, Brendan Choat
X-ray microtomography (microCT) is becoming a valuable noninvasive tool for advancing our understanding of plant-water relations. Laboratory-based microCT systems are becoming more affordable and provide better access than synchrotron facilities. However, some systems come at the cost of comparably lower signal quality and spatial resolution than synchrotron facilities. In this study, we evaluated laboratory-based X-ray microCT imaging as a tool to nondestructively analyse hydraulic vulnerability to drought-induced embolism in a woody plant species...
February 14, 2017: New Phytologist
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
#16
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
#17
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
#18
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
#19
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/28191970/various-arsenic-network-structures-in-112-type-ca1-xlaxfe1-ypdyas2-revealed-by-synchrotron-x-ray-diffraction-experiments
#20
Shinya Tamura, Naoyuki Katayama, Yuto Yamada, Yuki Sugiyama, Kento Sugawara, Hiroshi Sawa
Two novel 112-type palladium-doped iron arsenides were synthesized and identified using comprehensive studies involving synchrotron X-ray diffraction and X-ray absorption near-edge structure (XANES) experiments. Whereas in-plane arsenic zigzag chains were found in the 112-type superconducting iron arsenide Ca1-xLaxFeAs2 with maximum Tc = 34 K, deformed arsenic network structures appeared in other 112-type materials, such as longitudinal arsenic zigzag chains in CaFe1-yPdyAs2 (y ∼ 0.51) and arsenic square sheets constructed via hypervalent bonding in Ca1-xLaxFe1-yPdyAs2 (x ∼ 0...
February 13, 2017: Inorganic Chemistry
keyword
keyword
93585
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"