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https://www.readbyqxmd.com/read/28454063/interaction-of-amino-acid-functionalized-silver-nanoparticles-and-candida-albicans-polymorphs-a-deep-uv-fluorescence-imaging-study
#1
Radovan Dojčilović, Jelena D Pajović, Dušan K Božanić, Una Bogdanović, Vesna V Vodnik, Suzana Dimitrijević-Branković, Miona G Miljković, Slavka Kaščaková, Matthieu Réfrégiers, Vladimir Djoković
The interaction of the tryptophan functionalized Ag nanoparticles and live Candida albicans cells was studied by synchrotron excitation deep-ultraviolet (DUV) fluorescence imaging at the DISCO beamline of Synchrotron SOLEIL. DUV imaging showed that incubation of the fungus with functionalized nanoparticles results in significant increase in the fluorescence signal. The analysis of the images revealed that the interaction of the nanoparticles with (pseudo)hyphae polymorphs of the diploid fungus was less pronounced than in the case of yeast cells or budding spores...
April 23, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28447701/structural-and-morphological-transitions-in-extension-induced-crystallization-of-poly-1-butene-melt
#2
Zhen Wang, Jianzhu Ju, Lingpu Meng, Nan Tian, Jiarui Chang, Haoran Yang, Youxin Ji, Fengmei Su, Liangbin Li
Structural and morphological transitions of flow-induced crystallization (FIC) in poly(1-butene) (PB-1) melt have been studied by combining extensional rheology and in situ synchrotron radiation ultrafast wide- and small-angle X-ray scattering (WAXD/SAXS) measurements. Unexpectedly, metastable Form III is crystallized directly from the PB-1 melt by high-speed extension, which has a short lifetime of several tens of milliseconds and manifests the thermodynamic and kinetic competition among Form III, Form II and melt under flow...
April 27, 2017: Soft Matter
https://www.readbyqxmd.com/read/28447597/resonant-and-non-resonant-magnetic-scatterings-with-circularly-polarized-x-rays-magnetic-scattering-factor-and-electron-density-of-gadolinium-iron-garnet
#3
Yo Sasaki, Maki Okube, Satoshi Sasaki
Theoretical and experimental studies on resonant magnetic scattering have been carried out using circularly polarized X-rays. Polarization dependence of the asymmetric ratio between right- and left-handed polarized scattering amplitudes has revealed that resonant and non-resonant magnetic scatterings can be observed simultaneously. In this study, synchrotron X-ray intensity experiments were conducted on Gd iron garnet (GdIG) at the pre-edge of the Fe K absorption edge. The asymmetric ratio between circular polarizations exhibited three peaks due to the resonant magnetic responses of Fe(3+) in the Fe2 (24d) site...
May 1, 2017: Acta Crystallographica. Section A, Foundations and Advances
https://www.readbyqxmd.com/read/28445639/toward-covalent-organic-frameworks-bearing-three-different-kinds-of-pores-the-strategy-for-construction-and-cof-to-cof-transformation-via-heterogeneous-linker-exchange
#4
Cheng Qian, Qiao-Yan Qi, Guo-Fang Jiang, Fu-Zhi Cui, Yuan Tian, Xin Zhao
Covalent organic frameworks (COFs) are an emerging class of crystalline porous organic materials which are fabricated via reticular chemistry. Their topologic structures can be precisely predicted on the basis of the structures of building blocks. However, constructing COF with complicated structures has remained a great challenge, due to the limited strategies that can access to structural complexity of COFs. In this work, we have developed a new approach to produce COFs bearing three different kinds of pores...
April 26, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28445036/ag-nanoparticles-and-wheat-roots-a-complex-interplay
#5
Ana Elena Pradas Del Real, Vladimir Vidal, Marie Carriere, Hiram A Castillo-Michel, Clément Levard, Perrine Chaurand, Géraldine Sarret
Agricultural soils are major sinks of silver nanoparticles in the environment, and crops are directly exposed to these emerging contaminants. A clear picture of their chemical transformations, uptake and transport mechanisms, and phytotoxic impacts is still lacking. In this work, wheat plants were exposed to pristine metallic (Ag-NPs) and sulfidized (Ag2S-NPs) silver nanoparticles and ionic Ag. Data on Ag distribution and speciation, phytotoxicity markers and gene expression were studied. A multi-technique and multi-scale approach was applied combining innovating tools at both laboratory and synchrotron...
April 26, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28444564/response-to-lead-pollution-mycorrhizal-pinus-sylvestris-forms-the-biomineral-pyromorphite-in-roots-and-needles
#6
Maria L Bizo, Sandor Nietzsche, Ulrich Mansfeld, Falko Langenhorst, Juraj Majzlan, Jörg Göttlicher, Alexandru Ozunu, Steffi Formann, Katrin Krause, Erika Kothe
The development of mycorrhized pine seedlings grown in the presence of lead was assessed in order to investigate how higher plants can tolerate lead pollution in the environment. Examination with scanning electron microscopy (SEM) revealed that Pb uptake was prominent in the roots, while a smaller amount was found in pine needles, which requires symplastic uptake and root-to-shoot transfer. Lead was concentrated in nanocrystalline aggregates attached to the cell wall and, according to elemental microanalyses, is associated with phosphorus and chlorine...
April 25, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28443889/the-passivating-effect-of-cadmium-in-pbs-cds-colloidal-quantum-dots-probed-by-nm-scale-depth-profiling
#7
Pip C J Clark, Hanna Radtke, Atip Pengpad, Andrew I Williamson, Ben F Spencer, Samantha J O Hardman, Marina A Leontiadou, Darren C J Neo, Simon M Fairclough, Andrew A R Watt, Igor Pis, Silvia Nappini, Federica Bondino, Elena Magnano, Karsten Handrup, Karina Schulte, Mathieu G Silly, Fausto Sirotti, Wendy R Flavell
Achieving control of the surface chemistry of colloidal quantum dots (CQDs) is essential to fully exploit their properties in solar cells, but direct measurement of the chemistry and electronic structure in the outermost atomic layers is challenging. Here we probe the surface oxidation and passivation of cation-exchanged PbS/CdS core/shell CQDs with sub nm-scale precision using synchrotron-radiation-excited depth-profiling photoemission. We investigate the surface composition of the topmost 1-2.5 nm of the CQDs as a function of depth, for CQDs of varying CdS shell thickness, and examine how the surface changes after prolonged air exposure...
April 26, 2017: Nanoscale
https://www.readbyqxmd.com/read/28442718/pressure-induced-structural-change-in-liquid-gain-eutectic-alloy
#8
Q Yu, A S Ahmad, K Ståhl, X D Wang, Y Su, K Glazyrin, H P Liermann, H Franz, Q P Cao, D X Zhang, J Z Jiang
Synchrotron x-ray diffraction reveals a pressure induced crystallization at about 3.4 GPa and a polymorphic transition near 10.3 GPa when compressed a liquid GaIn eutectic alloy up to ~13 GPa at room temperature in a diamond anvil cell. Upon decompression, the high pressure crystalline phase remains almost unchanged until it transforms to the liquid state at around 2.3 GPa. The ab initio molecular dynamics calculations can reproduce the low pressure crystallization and give some hints on the understanding of the transition between the liquid and the crystalline phase on the atomic level...
April 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28441285/induced-radioactivity-in-lead-shielding-at-the-national-synchrotron-light-source
#9
Vinita J Ghosh, Charles Schaefer, Henry Kahnhauser
The National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory was shut down in September 2014. Lead bricks used as radiological shadow shielding within the accelerator were exposed to stray radiation fields during normal operations. The FLUKA code, a fully integrated Monte Carlo simulation package for the interaction and transport of particles and nuclei in matter, was used to estimate induced radioactivity in this shielding and stainless steel beam pipe from known beam losses. The FLUKA output was processed using MICROSHIELD® to estimate on-contact exposure rates with individually exposed bricks to help design and optimize the radiological survey process...
June 2017: Health Physics
https://www.readbyqxmd.com/read/28440916/high-temperature-crystal-structure-and-chemical-bonding-in-thermoelectric-germanium-selenide-gese
#10
Mattia Sist, Carlo Gatti, Peter Nørby, Simone Cenedese, Hidetaka Kasai, Kenichi Kato, Bo B Iversen
The discovery of the ultra-high thermoelectric figure of merit of 2.6 in SnSe has drawn attention to other lead-free IV-VI orthorhombic semiconductors. GeSe has been predicted to possess thermoelectric performances comparable to SnSe. Here, a complete structural study is reported of GeSe with temperature by means of high-resolution synchrotron powder X-ray diffraction. In the orthorhombic phase, the evolution of the bond distances with temperature is shown to deviate significantly with respect to SnSe. Analysis of the chemical bonding within the Quantum Theory of Atoms in Molecules shows that GeSe is ionic with van der Waals interlayer interactions...
April 25, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28440339/polyamorphism-in-yb-based-metallic-glass-induced-by-pressure
#11
Liangliang Li, Qiang Luo, Renfeng Li, Haiyan Zhao, Karena W Chapman, Peter J Chupas, Luhong Wang, Haozhe Liu
The Yb62.5Zn15Mg17.5Cu5 metallic glass is investigated using synchrotron x-ray total scattering method up to 38.4 GPa. The polyamorphic transformation from low density to high density with a transition region between 14.1 and 25.2 GPa is observed, accompanying with a volume collapse reflected by a discontinuousness of isothermal bulk modulus. This collapse is caused by that distortional icosahedron short range order precedes to perfect icosahedron, which might link to Yb 4f electron delocalization upon compression, and match the result of in situ electrical resistance measurement under high pressure conditions...
April 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28440079/pressure-induced-polymorphic-optical-and-electronic-transitions-of-formamidinium-lead-iodide-perovskite
#12
Pan Wang, Jiwen Guan, Draven T K Galeschuk, Yansun Yao, Cindy Fung He, Shan Jiang, Sijia Zhang, Ying Liu, Meiling Jin, Changqing Jin, Yang Song
Formamidinium lead iodide (FAPbI3) perovskite as a superior solar cell material was investigated in two polymorphs at high pressures using in situ synchrotron X-ray diffraction, FTIR spectroscopy, photoluminescence (PL) spectroscopy, electrical conductivity (EC) measurements, and ab initio calculations. We identified two new structures (i.e., Imm2 and Immm) for α-FAPbI3, but only a structural distortion (in C2/c) for δ-FAPbI3 on compression. Pressure-enhanced hydrogen bond plays a prominent role in structural modifications, as corroborated by FTIR spectroscopy...
April 25, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28437258/magnetic-resonance-study-of-exchange-biased-ni-nio-nanoparticles
#13
Ashish Chhaganlal Gandhi, Jauyn Grace Lin
Finite sized Ni/NiO nanoparticles (NPs) are prepared by oxidizing pure Ni-NPs in an ambient atmosphere with varying annealing time (t A). A synchrotron radiation x-ray diffraction technique was used to estimate the grain size, weight fraction and lattice parameters of Ni and NiO. The temperature (T) dependencies of effective g-factor and line-width of ferromagnetic resonance (FMR) spectra for a series of Ni/NiO NPs are determined. Three T-regions with different FMR behaviors T  >  200 K, 200  >  T  >  130 K and T  <  130 K are identified...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28437071/revealing-the-initial-reaction-behavior-in-the-continuous-synthesis-of-metal-organic-frameworks-using-real-time-synchrotron-x-ray-analysis
#14
Angelos Polyzoidis, Martin Etter, Michael Herrmann, Stefan Loebbecke, Robert E Dinnebier
In recent years, continuous process technologies have attracted increasing attention, as a means of overcoming limitations in the repeatability and reproducibility of metal-organic framework (MOF) synthesis. Research in this area, however, has neglected to provide insight into the phenomenon leading to the formation of MOFs. In this work, we report the adaption of high-energy synchrotron powder X-ray diffraction analysis to a continuous ZIF-8 production process for online monitoring of the reaction behavior and crystallite formation during the first seconds of the MOF synthesis...
April 24, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28436610/atomic-interface-engineering-and-electric-field-effect-in-ultrathin-bi2-moo6-nanosheets-for-superior-lithium-ion-storage
#15
Yang Zheng, Tengfei Zhou, Xudong Zhao, Wei Kong Pang, Hong Gao, Sean Li, Zhen Zhou, Huakun Liu, Zaiping Guo
Ultrathin 2D materials can offer promising opportunities for exploring advanced energy storage systems, with satisfactory electrochemical performance. Engineering atomic interfaces by stacking 2D crystals holds huge potential for tuning material properties at the atomic level, owing to the strong layer-layer interactions, enabling unprecedented physical properties. In this work, atomically thin Bi2 MoO6 sheets are acquired that exhibit remarkable high-rate cycling performance in Li-ion batteries, which can be ascribed to the interlayer coupling effect, as well as the 2D configuration and intrinsic structural stability...
April 24, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28436146/improving-zinc-accumulation-in-barley-endosperm-using-hvmtp1-a-transition-metal-transporter
#16
Paloma Menguer, Thomas Vincent, Anthony J Miller, James K M Brown, Eva Vincze, Søren Borg, Preben Bach Holm, Dale Sanders, Dorina Podar
Zinc (Zn) is essential for all life forms, including humans. It is estimated that around two billion people are deficient in their Zn intake. Human dietary Zn intake relies heavily on plants, which in many developing countries consists mainly of cereals. The inner part of cereal grain, the endosperm, is the part that is eaten after milling but contains only a quarter of the total grain Zn. Here we present results demonstrating that endosperm Zn content can be enhanced through expression of a transporter responsible for vacuolar Zn accumulation in cereals...
April 24, 2017: Plant Biotechnology Journal
https://www.readbyqxmd.com/read/28435962/dissociation-of-cyclopropane-in-double-ionization-continuum
#17
Shabnam Oghbaie, Mathieu Gisselbrecht, Erik P Månsson, Joakim Laksman, Christian Stråhlman, Anna Sankari, Stacey L Sorensen
Dissociative double photoionization of cyclopropane is studied in the inner-valence region using tunable synchrotron radiation. With the aid of ab initio quantum chemical calculations the energies of dication states and their favoured fragmentation pathways are determined. These are compared to the experimental appearance energies of two-body fragmentation processes and to the kinetic energy released upon dissociation. Photon energy dependent state-selective dissociation in the 25-35 eV range is found. Calculations of dissociation pathways suggest that cyclopropane ring-deformation is selectively triggered at certain photon energies...
April 24, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28429762/annealing-induced-re-crystallization-in-ch3nh3pbi3-xclx-for-high-performance-perovskite-solar-cells
#18
Yingguo Yang, Shanglei Feng, Meng Li, Weidong Xu, Guangzhi Yin, Zhaokui Wang, Baoquan Sun, Xingyu Gao
Using poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as hole conductor, a series of inverted planar CH3NH3PbI3-xClx perovskite solar cells (PSCs) were fabricated based on perovskite annealed by an improved time-temperature dependent (TTD) procedure in a flowing nitrogen atmosphere for different time. Only after an optimum annealing time, an optimized power conversion efficiency of 14.36% could be achieved. To understand their performance dependence on annealing time, an in situ real-time synchrotron-based grazing incidence X-ray diffraction (GIXRD) was used to monitor a step-by-step gradual structure transformation from distinct mainly organic-inorganic hybrid materials into highly ordered CH3NH3PbI3 crystal during annealing...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28428993/from-nano-to-microcrystals-effects-of-different-synthetic-pathways-on-the-defect-architecture-in-heavily-gd-doped-ceria
#19
M Coduri, M Scavini, M Pani, M M Carnasciali, H Klein, C Artini
The evolution of the defect structure and microstructure of heavily Gd-doped ceria (Ce1-μREμO2-y, 0.313 ≤ μ ≤ 0.438) for different synthetic pathways is investigated here to explore the way defects interact with each other in a composition range known to effectively hamper the application of the material as an electrolyte. Synchrotron radiation powder diffraction is exploited by combining conventional Rietveld analysis with the Pair Distribution Function to get a multiscale picture of defect structures, and it is combined with Raman spectroscopy to assess local scale interactions...
April 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28428974/perspective-a-toolbox-for-protein-structure-determination-in-physiological-environment-through-oriented-2d-ordered-site-specific-immobilization
#20
M Altissimo, M Kiskinova, R Mincigrucci, L Vaccari, C Guarnaccia, C Masciovecchio
Revealing the structure of complex biological macromolecules, such as proteins, is an essential step for understanding the chemical mechanisms that determine the diversity of their functions. Synchrotron based X-ray crystallography and cryo-electron microscopy have made major contributions in determining thousands of protein structures even from micro-sized crystals. They suffer from some limitations that have not been overcome, such as radiation damage, the natural inability to crystallize a number of proteins, and experimental conditions for structure determination that are incompatible with the physiological environment...
July 2017: Structural Dynamics (Melville, N.Y.)
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