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Lei Hu, Jun Chen, Jiale Xu, Na Wang, Fei Han, Yang Ren, Zhao Pan, Yangchun Rong, Rongjin Huang, Jinxia Deng, Laifeng Li, Xianran Xing
The controllable isotropic thermal expansion with a broad coefficient of thermal expansion (CTE) window is intriguing but remains challenge. Herein we report a cubic MZrF6 series (M = Ca, Mn, Fe, Co, Ni and Zn), which exhibit controllable thermal expansion over a wide temperature range and with a broader CTE window (-6.69 to +18.23×10-6/K). In particular, an isotropic zero thermal expansion (ZTE) is achieved in ZnZrF6, which is one of the rarely documented high-temperature isotropic ZTE compounds. By utilizing temperature-dependent high-energy synchrotron X-ray total scattering diffraction, it is found that the flexibility of metal∙∙∙F atomic linkages in MZrF6 plays a critical role in distinct thermal expansions...
October 26, 2016: Journal of the American Chemical Society
Xiaolin Wang, Qiao Yang, Yixue Cao, Haibin Hao, Junhan Zhou, Jingcheng Hao
The gelation behavior of cationic surfactants with different counterions, Br(-) , [FeCl3 Br](-) , and [CeCl3 Br](-) , in imidazolium ionic liquids (ILs) and protic ethylammonium nitrate was investigated. Small-angle X-ray scattering measurements and freeze-fracture transmission electron microscopy observations revealed the lamellar phases of metallosurfactant ionogels. The characteristics of imidazolium ILs, including the size and type, have effects on metallosurfactant ionogel properties, such as transformation temperatures, interlayer spacing, and mechanical strength...
October 26, 2016: Chemistry: a European Journal
Soo Hyeon Lim, Eun-Young Ahn, Youmie Park
Gold nanoparticles were synthesized using a water extract of Artemisia capillaris (AC-AuNPs) under different extract concentrations, and their catalytic activity was evaluated in a 4-nitrophenol reduction reaction in the presence of sodium borohydride. The AC-AuNPs showed violet or wine colors with characteristic surface plasmon resonance bands at 534~543 nm that were dependent on the extract concentration. Spherical nanoparticles with an average size of 16.88 ± 5.47~29.93 ± 9.80 nm were observed by transmission electron microscopy...
December 2016: Nanoscale Research Letters
Jun Dang, Fang-Fang Yin, Tao You, Chunhua Dai, Deyu Chen, Jing Wang
PURPOSE: Current approaches using deformable vector field (DVF) for motion-compensated 4D-cone beam CT (CBCT) reconstruction typically utilize an isotropically smoothed DVF between different respiration phases. Such isotropically smoothed DVF does not work well if sliding motion exists between neighboring organs. This study investigated an anisotropic motion modeling scheme by extracting organ boundary local motions (e.g., sliding) and incorporated them into 4D-CBCT reconstruction to optimize the motion modeling and reconstruction methods...
October 2016: Medical Physics
Chuan Zhou, Heang-Ping Chan, Lubomir M Hadjiiski, Aamer Chughtai, Jun Wei, Ella A Kazerooni
PURPOSE: The authors are developing an automated method to identify the best-quality coronary arterial segment from multiple-phase coronary CT angiography (cCTA) acquisitions, which may be used by either interpreting physicians or computer-aided detection systems to optimally and efficiently utilize the diagnostic information available in multiple-phase cCTA for the detection of coronary artery disease. METHODS: After initialization with a manually identified seed point, each coronary artery tree is automatically extracted from multiple cCTA phases using our multiscale coronary artery response enhancement and 3D rolling balloon region growing vessel segmentation and tracking method...
October 2016: Medical Physics
Wissam A Saidi, Joshua J Choi
Hybrid organic-inorganic perovskites, as well as the perovskites in general, are known for their phase complexity evidenced by the stabilization of different polymorphs, and thus an understanding of their regions of stability and transitions can be important for their photovoltaic and optoelectronic technologies. Here we use a multiscale approach based on first-principles calculations with van der Waals corrections and classical force-field molecular dynamics to determine the finite-temperature properties of the tetragonal and cubic phases of CH3NH3PbI3...
October 14, 2016: Journal of Chemical Physics
Russell K W Spencer, Paul F Curry, Robert A Wickham
We examine nucleation of the stable body-centred-cubic (BCC) phase from the metastable uniform disordered phase in an asymmetric diblock copolymer melt. Our comprehensive, large-scale simulations of the time-dependent, mean-field Landau-Brazovskii model find that spherical droplets of the BCC phase nucleate directly from disorder. Near the order-disorder transition, the critical nucleus is large and has a classical profile, attaining the bulk BCC phase in an interior that is separated from disorder by a sharp interface...
October 14, 2016: Journal of Chemical Physics
Chandrashekhar V Kulkarni, Anan Yaghmur, Miloš Steinhart, Manfred Kriechbaum, Michael Rappolt
We present the first report on the effect of hydrostatic pressure on colloidally stabilized lipid nanoparticles enveloping inverse non-lamellar self-assemblies in their interiors. These internal self-assemblies were systematically tuned into bicontinuous cubic (Pn3m and Im3m), micellar cubic (Fd3m), hexagonal (H2), and inverse micellar (L2) phases by regulating the lipid-oil ratio while the hydrostatic pressure was varied from atmospheric pressure to 1200 bar, and back to the atmospheric pressure. The pressure effect on these lipid nanoparticles was compared with their equilibrium bulk, non-dispersed counterparts, i...
October 26, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Zhendong Fu, Yinguo Xiao, Artem Feoktystov, Vitaliy Pipich, Marie-Sousai Appavou, Yixi Su, Erxi Feng, Wentao Jin, Thomas Brückel
The magnetic-field-induced assembly of magnetic nanoparticles (NPs) provides a unique and flexible strategy in the design and fabrication of functional nanostructures and devices. We have investigated the field-induced self-assembly of core-shell iron oxide NPs dispersed in toluene by means of small-angle neutron scattering (SANS). The form factor of the core-shell NPs was characterized and analyzed using SANS with polarized neutrons. Large-scale aggregates of iron oxide NPs formed above 0.02 T as indicated by very-small-angle neutron scattering measurements...
October 26, 2016: Nanoscale
Jan Wilhelm, Patrick Seewald, Mauro Del Ben, Juerg Hutter
We present an algorithm for computing the correlation energy in the random phase approximation (RPA) in a Gaussian basis requiring $\mathcal{O}(N^3)$ operations and $\mathcal{O}(N^2)$ memory. The method is based on the resolution of the identity (RI) with the overlap metric, a reformulation of RI-RPA in the Gaussian basis, imaginary time and imaginary frequency integration techniques and the use of sparse linear algebra. Additional memory reduction without extra computations can be achieved by an iterative scheme which overcomes the memory bottleneck of canonical RPA implementations...
October 25, 2016: Journal of Chemical Theory and Computation
Jianyan Ding, Quansheng Wu, Yanyan Li, Qiang Long, Yichao Wang, Xinlong Ma, Yuhua Wang
Defect luminescence has been considered to be one of the most efficient ways to resolve the problem of the recent limited supply and increased demand for rare-earth elements. So, in this work, a novel self-activated long-persistent green-yellow and yellow emitting phosphors of α-Ca3B2N4 and β-Ca3B2N4 has been successfully synthesized by sample-pressuring sintering. The α-Ca3B2N4 and β-Ca3B2N4 all have a broad excitation band peaked at 300 and 350 nm and emit yellow-green light peaked at 550 nm and yellow light peaked at 575 nm respectively with the long afterglow properties...
October 25, 2016: Inorganic Chemistry
Jade Taffs, C Patrick Royall
Although long assumed to have an important role in the suppression of crystallization and the development of glassformers, the effect of local fivefold symmetry has never been directly tested. Here we consider whether such suppression of crystallization has a kinetic or thermodynamic nature and investigate its mechanism. We introduce a model in which the degree of fivefold symmetry can be tuned by favouring arrangements of particles in pentagonal bipyramids. We thus show that fivefold symmetry has both kinetic and thermodynamic effects on the mechanism of crystallization to a face-centred cubic crystal...
October 25, 2016: Nature Communications
M A Timirgazin, P A Igoshev, A K Arzhnikov, V Yu Irkhin
The ground-state magnetic phase diagram (including collinear and spiral states) of the single-band Hubbard model for the face-centered cubic lattice and related metal-insulator transition (MIT) are investigated within the slave-boson approach by Kotliar and Ruckenstein. The correlation-induced electron spectrum narrowing and a comparison with a generalized Hartree-Fock approximation allow one to estimate the strength of correlation effects. This, as well as the MIT scenario, depends dramatically on the ratio of the next-nearest and nearest electron hopping integrals [Formula: see text]...
October 25, 2016: Journal of Physics. Condensed Matter: An Institute of Physics Journal
D R Bhardwaj, Muneesa Banday, Nazir A Pala, Bhalendra Singh Rajput
In the present study, forests at three altitudes, viz., A1 (600-900 m), A2 (900-1200 m) and A3 (1200-1500 m) above mean sea level having normalised differential vegetation index (NDVI) values of N1 (0.0-0.1), N2 (0.1-0.2), N3 (0.2-0.3), N4 (0.3-0.4) and N5 (0.4-0.5) were selected for studying their relationship with the biomass and carbon pool in the state of Himachal Pradesh, India. The study reported maximum stem density of (928 trees ha(-1)) at the A2 altitude and minimum in the A3 and A1 with 600 trees ha(-1) each...
November 2016: Environmental Monitoring and Assessment
Anupam Ghosh, Anilava Kaviraj, Subrata Saha
Experiments with environmentally relevant concentrations of Cu in glass aquaria revealed that Cu was quickly removed from water. Cubic regression of Cu concentration against time showed that maximum rate of removal was around 69.34-72.11 h irrespective of treatment. The 96 h LC50 value of Cu was respectively 0.18, 0.19 and 0.35 mg/L for fish Cyprinus carpio, crustacean Diaptomus forbesi and worm Branchiura sowerbyi. Normalizing the lethal values and plotting them against time it was observed that there was sharp differences in mortality over time between the organisms and 96 h lethal values could misrepresent susceptibility of the organisms to Cu...
October 24, 2016: Bulletin of Environmental Contamination and Toxicology
Takahiro Ichikawa, Akiyoshi Okafuji, Takashi Kato, Hiroyuki Ohno
The Back Cover picture illustrates the attachment of iodine atoms onto the headgroup of an amphiphilic zwitterion, which leads to the formation of a bicontinuous cubic liquid-crystalline assembly with a primitive-type infinite periodic minimal surface. More information can be found in the Communication by T. Ichikawa, H. Ohno and co-workers on page 439 in Issue 5, 2016 (DOI: 10.1002/open.201600054).
October 2016: ChemistryOpen
Takahiro Ichikawa, Akiyoshi Okafuji, Takashi Kato, Hiroyuki Ohno
We have designed an amphiphilic zwitterion with an iodine-substituted imidazolium cation. Although it forms a layered assembly with flat interfaces, the addition of an equimolar amount of bis(trifluoromethane)sulfonimide results in the formation of a bicontinuous cubic liquid-crystalline assembly with a primitive-type infinite periodic minimal surface, where its zwitterionic headgroup sits regularly. IR measurements revealed that halogen bond between the iodine atoms on the imidazolium cation and the anions is involved in its molecular-assembly behavior...
October 2016: ChemistryOpen
Appiah-Korang Labi, Noah Obeng-Nkrumah, Stephanie Bjerrum, Christabel Enweronu-Laryea, Mercy Jemima Newman
BACKGROUND: Diagnosis of bloodstream infections (BSI) in neonates is usually difficult due to minimal symptoms at presentation; thus early empirical therapy guided by local antibiotic susceptibility profile is necessary to improve therapeutic outcomes. METHODS: A review of neonatal blood cultures submitted to the microbiology department of the Korle-Bu Teaching Hospital was conducted from January 2010 through December 2013. We assessed the prevalence of bacteria and fungi involved in BSI and the susceptibility coverage of recommended empiric antibiotics by Ghana Standard Treatment guidelines and the WHO recommendations for managing neonatal sepsis...
October 24, 2016: BMC Infectious Diseases
S K Jesudoss, J Judith Vijaya, L John Kennedy, P Iyyappa Rajan, Hamad A Al-Lohedan, R Jothi Ramalingam, K Kaviyarasu, M Bououdina
The present work describes the successful synthesize of spinel magnetic ferrite Mn1-xNixFe2O4 (x=0.0, 0.1, 0.2, 0.3, 0.4 & 0.5) nanoparticles via a simple microwave combustion method which was then evaluated for its photocatalytic activity in the degradation of indigo carmine (IC) synthetic dye, a major water pollutant. Our results reveal that the synthesized of Ni(2+) doped MnFe2O4 nanoparticles possess well-crystalline pure cubic spinel phase, exhibit excellent optical and magnetic properties. Further, the photocatalytic performance of the synthesized nanoparticles at different concentration ratios of Ni(2+) ions was monitored by photocatalytic degradation of indigo carmine synthetic dye under UV (λ=365nm) light irradiation...
October 8, 2016: Journal of Photochemistry and Photobiology. B, Biology
Oleksandr O Kurakevych, Vladimir L Solozhenko
The aim of the present review is to highlight the state of the art in high-pressure design of new advanced materials based on boron nitride. Recent experimental achievements on the governing phase transformation, nanostructuring and chemical synthesis in the systems containing boron nitride at high pressures and high temperatures are presented. All these developments allowed discovering new materials, e.g., ultrahard nanocrystalline cubic boron nitride (nano-cBN) with hardness comparable to diamond, and superhard boron subnitride B13N₂...
October 20, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
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