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https://www.readbyqxmd.com/read/28335368/shape-evolution-of-hierarchical-w18o49-nanostructures-a-systematic-investigation-of-the-growth-mechanism-properties-and-morphology-dependent-photocatalytic-activities
#1
Guojuan Hai, Jianfeng Huang, Liyun Cao, Yanni Jie, Jiayin Li, Xing Wang
Hierarchical tungsten oxide assemblies such as spindle-like structures, flowers with sharp petals, nanowires and regular hexagonal structures are successfully synthesized via a solvothermal reduction method by simply adjusting the reaction conditions. On the basis of the experimental results, it is determined that the reaction time significantly influences the phase transition, microstructure and photocatalytic activity of the prepared samples. The possible mechanisms for the morphology evolution process have been systematically proposed...
December 14, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335025/a-novel-lc-ms-ms-method-with-an-effective-antioxidant-for-the-determination-of-edaravone-a-free-radical-scavenger-in-dog-plasma-and-its-application-to-a-pharmacokinetic-study
#2
Feng Shao, Xiao-Ling Hu, Xin Liu, Mang-Ting Shan
The objective of this study was to investigate the stability of edaravone in dog plasma by using an added antioxidant stabilizer, with an ultimate goal of developing and validating a sensitive, reliable and robust LC-MS-MS method for determination of edaravone in plasma samples. Edaravone was unstable in plasma, but it presented a good stability performance in the plasma with sodium metabisulfite (SMB), an effective antioxidant. The blood sample was collected in the heparinized eppendorf tube containing SMB and plasma sample was deproteinized using acetonitrile containing 20 ng/mL of phenacetin (Internal standard)...
March 2, 2017: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/28334631/internalizing-and-externalizing-disorders-in-childhood-and-adolescence-a-latent-transition-analysis-using-alspac-data
#3
Eoin McElroy, Mark Shevlin, Jamie Murphy
BACKGROUND: Research examining the association between internalizing and externalizing dimensions of psychopathology has relied heavily on variable-centered analytical techniques. Person-centered methodologies complement the variable-centered approach, and may help explain the medium-to-large correlations that exist between higher order dimensions of psychopathology. What little person-centered research exists has been cross-sectional and utilized adult samples. The present study sought to take a person-centered approach to the modeling of psychiatric comorbidity during a key developmental phase; middle childhood through adolescence...
March 12, 2017: Comprehensive Psychiatry
https://www.readbyqxmd.com/read/28333462/lattice-solvent-effects-in-the-spin-crossover-of-an-fe-ii-based-material-the-key-role-of-intermolecular-interactions-between-solvent-molecules
#4
Maria Fumanal, Fernando Jiménez-Grávalos, Jordi Ribas-Arino, Sergi Vela
The spin transition of Fe(II) complexes is the subject of intensive synthetic and computational efforts. In this manuscript, we analyze the spin crossover (SCO) of [Fe(E-dpsp)2](2+) (1), which features a spin transition depending on the cocrystallizing solvent molecules. Whereas the use of acetone results in a hysteretic spin transition at ∼170 K, the use of propylene carbonate (PC) results in a permanent diamagnetic signal up to 300 K. By means of DFT+U+D2 calculations in the solid state of the material, we unravel the reasons for such different behavior...
March 23, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28332691/relaxations-and-phase-transitions-during-the-collapse-of-a-dense-pnipam-microgel-suspension-thorough-insight-using-dielectric-spectroscopy
#5
Man Yang, Chunyan Liu, Yiwei Lian, Kongshuang Zhao, Dan Zhu, Jianfeng Zhou
The dielectric behavior of a thermo-sensitive poly-(N-isopropylacrylamide) (PNIPAM) microgel suspension with a dense concentration was investigated over the frequency range of 40 Hz to 110 MHz in a wide temperature window of 10-60 °C. By successfully removing the electrode polarization effect from the original data, two remarkable and temperature-dependent relaxation processes were observed. Both of the two-phase transition processes, i.e., the colloidal crystal-to-liquid transition, which has not yet been detected by dielectric spectroscopy before, as well as the volume phase transition, were detected by the relaxation parameters...
March 23, 2017: Soft Matter
https://www.readbyqxmd.com/read/28332683/tailoring-adsorption-induced-phase-transitions-in-the-pillared-layer-type-metal-organic-framework-dut-8-ni
#6
Negar Kavoosi, Volodymyr Bon, Irena Senkovska, Simon Krause, Cesare Atzori, Francesca Bonino, Julia Pallmann, Silvia Paasch, Eike Brunner, Stefan Kaskel
Tailoring the characteristics of gating transitions in the porous network, Ni2(ndc)2dabco (ndc = 2,6-naphthalenedicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]octane), also termed DUT-8(Ni) (DUT = Dresden University of Technology), was achieved by systematically adjusting the critical synthesis parameters. The impact of the starting composition and solvent mixtures in the synthesis was found to critically affect the guest-response properties of the obtained materials. A comprehensive set of physical characterization methods, namely thermal analysis, (1)H NMR of digested crystals, solid state (13)C NMR, PXRD, SEM, IR and Raman spectroscopy shows that the crystallite size is a crucial factor, determining the differing characteristics such as "gate pressure" and adsorption capacity in the guest-responsive switching behaviour of DUT-8...
March 23, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28332670/high-temperature-structural-phase-transition-coupled-with-dielectric-switching-in-an-organic-inorganic-hybrid-crystal-nh3-ch2-2br-3cdbr5
#7
Hai-Peng Chen, Zhong-Xia Wang, Cheng Chen, Yang Lu, Zi Yin, Xiao-Fen Sun, Da-Wei Fu
Molecular bistable switches (electrical switches "ON" and "OFF") represent a class of highly desirable intelligent materials due to their sensitive switchable responses, simple and environmentally friendly processing, light weight, and mechanical flexibility. In particular, these switches above room temperature with potential practical application are rarely reported. In this work, a new zigzag chained organic-inorganic hybrid compound [NH3(CH2)2Br]3CdBr5 (1), which displays rapidly sensitive dielectric switching reversibility and remarkable switching antifatigue, has been successfully synthesized...
March 23, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28332323/ramp-reversal-memory-and-phase-boundary-scarring-in-transition-metal-oxides
#8
Naor Vardi, Elihu Anouchi, Tony Yamin, Srimanta Middey, Michael Kareev, Jak Chakhalian, Yonatan Dubi, Amos Sharoni
Transition metal oxides are complex electronic systems that exhibit a multitude of collective phenomena. Two archetypal examples are VO2 and NdNiO3 , which undergo a metal-insulator phase transition (MIT), the origin of which is still under debate. Here this study reports the discovery of a memory effect in both systems, manifested through an increase of resistance at a specific temperature, which is set by reversing the temperature ramp from heating to cooling during the MIT. The characteristics of this ramp-reversal memory effect do not coincide with any previously reported history or memory effects in manganites, electron-glass or magnetic systems...
March 23, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28331174/development-of-customized-18-f-fluoride-elution-techniques-for-the-enhancement-of-copper-mediated-late-stage-radiofluorination
#9
Andrew V Mossine, Allen F Brooks, Naoko Ichiishi, Katarina J Makaravage, Melanie S Sanford, Peter J H Scott
In a relatively short period of time, transition metal-mediated radiofluorination reactions have changed the PET radiochemistry landscape. These reactions have enabled the radiofluorination of a wide range of substrates, facilitating access to radiopharmaceuticals that were challenging to synthesize using traditional fluorine-18 radiochemistry. However, the process of adapting these new reactions for automated radiopharmaceutical production has revealed limitations in fitting them into the confines of traditional radiochemistry systems...
March 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28330345/coexistence-of-low-and-high-overlap-phases-in-a-supercooled-liquid-an-integral-equation-investigation
#10
Jean-Marc Bomont, Giorgio Pastore, Jean-Pierre Hansen
The pair structure, free energy, and configurational overlap order parameter Q of an annealed system of two weakly coupled replicas of a supercooled "soft sphere" fluid are determined by solving the hypernetted-chain (HNC) and self-consistent Rogers-Young (RY) integral equations over a wide range of thermodynamic conditions ρ (number-density), T (temperature), and inter-replicas couplings ε12. Analysis of the resulting effective (or Landau) potential W(ρ,T; Q) and of its derivative with respect to Q confirms the existence of a "precursor transition" between weak and strong overlap phases below a critical temperature Tc well above the temperature To of the "ideal glass" transition observed in the limit ε12→0...
March 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28328215/synthesis-and-mechanical-character-of-hexagonal-phase-%C3%AE-wn
#11
Changchun Wang, Qiang Tao, Shushan Dong, Xin Wang, Pinwen Zhu
In this work, high-quality bulk WC-structured WN (δ-WN) was synthesized via an untraditional method and the structure was accurately determined by X-ray diffraction and Rietveld refinement. In the process of synthesizing δ-WN, W2N3 and melamine were used as tungsten source and nitrogen source, respectively. The result of successfully synthesized high-quality δ-WN indicates that our method is an effective route for synthesizing high-quality bulk δ-WN and melamine is a pure nitrogen source for introducing the nitrogen to the metal precursor...
March 22, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28327774/huge-magnetoresistance-induced-by-half-metal-semiconductor-phase-transition-in-a-one-dimensional-spin-chain-a-first-principles-study
#12
Jing Zeng, Ke-Qiu Chen
In experimental studies, magnetoresistance (MR) values of 10(3) are hard to reach for conventional single-molecule spin-valves. Motivated by a recent experiment [Nano Lett., 2016, 16, 577-582], where tailored Co-salophene-based all-spin molecular devices are successfully realized, we demonstrate the functionality of a Co-salophene-based spin chain without magnetic electrodes. By using nonequilibrium Green's functions in combination with density functional theory, we find that the maximum MR ratio of this spin chain can reach 10(6) by manipulating its spins in a controlled way, which is several orders of magnitude higher than previously reported experimental values...
March 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28327724/reversible-crystal-to-crystal-chiral-resolution-making-breaking-non-bonding-so-interactions
#13
R Alex Mayo, David J Sullivan, Travis A P Fillion, Stefan W Kycia, Dmitriy V Soldatov, Kathryn E Preuss
An achiral organic molecule adopts a chiral conformation, crystallizing in two morphologies: a racemic form, stable <70 °C, and a homochiral form, stable ≥70 °C. Upon seeding, crystal-to-crystal phase transitions occur reversibly between the racemic and chiral forms. Liquid-to-solid chiral crystallization is observed >90% of the time from the melt.
March 22, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28327704/preparation-and-phase-transition-of-feooh-nanorods-strain-effects-on-catalytic-water-oxidation
#14
Gisang Park, Yong-Il Kim, Young Heon Kim, Mira Park, Kyu Yeon Jang, Hyunjoon Song, Ki Min Nam
The evolution of the phase and morphology of FeOOH nanorods prepared by a hydrothermal method is studied via X-ray diffraction (XRD) and in situ transmission electron microscopy. The FeOOH nanorod with a tetragonal structure (β-FeOOH) is gradually converted into a rhombohedral Fe2O3 nanorod by a simple thermal treatment. The existence of an intermediate FeOOH structure with high lattice strains during the phase transition is identified by Rietveld analysis using XRD. The electrochemical properties of the nanorods are investigated based on the crystal phases to elucidate their relative catalytic activities...
March 22, 2017: Nanoscale
https://www.readbyqxmd.com/read/28327622/continuously-varying-critical-exponents-beyond-weak-universality
#15
N Khan, P Sarkar, A Midya, P Mandal, P K Mohanty
Renormalization group theory does not restrict the form of continuous variation of critical exponents which occurs in presence of a marginal operator. However, the continuous variation of critical exponents, observed in different contexts, usually follows a weak universality scenario where some of the exponents (e.g., β, γ, ν) vary keeping others (e.g., δ, η) fixed. Here we report ferromagnetic phase transition in (Sm1-yNdy)0.52Sr0.48MnO3 (0.5 ≤ y ≤ 1) single crystals where all three exponents β, γ, δ vary with Nd concentration y...
March 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28327465/anomalous-rashba-spin-orbit-interaction-in-electrically-controlled-topological-insulator-based-on-inn-gan-quantum-wells
#16
S P Lepkowski, Witold Bardyszewski
We study theoretically the topological phase transition and the Rashba spin-orbit interaction in electrically biased InN/GaN quantum wells. We show that that for properly chosen widths of quantum wells and barriers, one can effectively tune the system through the topological phase transition applying an external electric field perpendicular to the QW plane. We find that in InN/GaN quantum wells with the inverted band structure, when the conduction band s-type level is below the heavy hole and light hole p-type levels, the spin splitting of the subbands decreases with increasing the amplitude of the electric field in the quantum wells, which reveals the anomalous Rashba effect...
March 22, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28327454/collective-variables-for-the-study-of-long-time-kinetics-from-molecular-trajectories-theory-and-methods
#17
REVIEW
Frank Noé, Cecilia Clementi
Collective variables are an important concept to study high-dimensional dynamical systems, such as molecular dynamics of macromolecules, liquids, or polymers, in particular to define relevant metastable states and state-transition or phase-transition. Over the past decade, a rigorous mathematical theory has been formulated to define optimal collective variables to characterize slow dynamical processes. Here we review recent developments, including a variational principle to find optimal approximations to slow collective variables from simulation data, and algorithms such as the time-lagged independent component analysis...
March 16, 2017: Current Opinion in Structural Biology
https://www.readbyqxmd.com/read/28327432/feedback-from-arctic-charr-feed-flavour-stimulation-and-re-feeding-after-feed-deprivation-stimulate-genes-encoding-both-orexigenic-and-anorexigenic-neuropeptides
#18
Anja Striberny, Even H Jørgensen
Despite vast research attention, the knowledge about central mechanisms of appetite regulation in teleost remains inconclusive. A common strategy in studies on appetite regulating mechanisms is to measure the response to feed restriction or - deprivation, but responses vary between fish species and between experiments, and are also likely dependent on the degree of energy perturbation. The anadromous Arctic charr is an interesting model for studying appetite regulation as its feeding cycle comprises months of winter anorexia, and hyperphagia during summer...
March 18, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/28326753/effects-of-essential-oil-exposure-on-salivary-estrogen-concentration-in-perimenopausal-women
#19
(no author information available yet)
OBJECTIVES: The menopausal transition is the time from the onset of menstrual changes until one year after the final menstrual period. During this phase, perimenopausal women experience a variety of health-related symptoms, which seemingly derive from declining level of estrogen secretion. It has long been recognized that some essential oils have the efficacy of alleviating menopausal symptoms. On the basis of this, it is possible that these essential oils have the potency to facilitate estrogen secretion in women...
January 22, 2017: Neuro Endocrinology Letters
https://www.readbyqxmd.com/read/28326629/solvent-controlled-phase-transition-of-a-co-ii-organic-framework-from-achiral-to-chiral-and-two-to-three-dimen-sion
#20
Xing-Po Wang, Wen-Miao Chen, Xiao-Yu Li, Cyril Rajnák, Zhen-Yu Feng, Mohamedally Kurmoo, Roman Boča, Chunjiang Jia, Chen-Ho Tung, Di Sun
We report an unprecedented reversible dynamic transformation in a metal-organic framework involving bond formation that is accompanied by two important structural changes, achiral to chiral and two- to three-dimension. Using two bent organic lig-ands (diimpym = 4,6-di(1H-imidazol-1-yl)pyrimidine; H2npta = 5-nitroisophthalic acid) and CoII(NO3)2*6H2O the coordination pol-ymer Co(diimpym)(npta)*CH3OH, 1*CH3OH, was obtained sol-vothermally. Its structure consisting of knitted pairs of square layers (44-sql) of five-coordinated Co, disordered methanol and crystallizing in achiral Pbca space group at room temperature undergoes a single-crystal to single-crystal (SC-SC) transfor-mation to a 3D interpenetrated framework (pcu) of six-coordinated Co and ordered methanol in chiral P212121 space group below 220 K...
March 21, 2017: Chemistry: a European Journal
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