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https://www.readbyqxmd.com/read/28642551/aesthetic-preformed-crowns-for-primary-teeth
#1
Greig D Taylor
Data sourcesMedline, Cochrane central register of controlled trials, US National Institutes of Health Trials Register and the World Health Organization International Clinical Trials Registry Platform.Study selectionEnglish language randomised clinical trials comparing APCs with conventional restorative techniques for primary teeth.Data extraction and synthesisStudy selection and data abstraction were conducted independently by two reviewers. Risk of bias was assessed using the Cochrane risk of bias tool. Study characteristics and results were described qualitatively...
June 23, 2017: Evidence-based Dentistry
https://www.readbyqxmd.com/read/28619940/rapid-cooling-and-cold-storage-in-a-silicic-magma-reservoir-recorded-in-individual-crystals
#2
Allison E Rubin, Kari M Cooper, Christy B Till, Adam J R Kent, Fidel Costa, Maitrayee Bose, Darren Gravley, Chad Deering, Jim Cole
Silicic volcanic eruptions pose considerable hazards, yet the processes leading to these eruptions remain poorly known. A missing link is knowledge of the thermal history of magma feeding such eruptions, which largely controls crystallinity and therefore eruptability. We have determined the thermal history of individual zircon crystals from an eruption of the Taupo Volcanic Zone, New Zealand. Results show that although zircons resided in the magmatic system for 10(3) to 10(5) years, they experienced temperatures >650° to 750°C for only years to centuries...
June 16, 2017: Science
https://www.readbyqxmd.com/read/28598143/composite-polymer-electrolytes-with-li7la3zr2o12-garnet-type-nanowires-as-ceramic-fillers-mechanism-of-conductivity-enhancement-and-role-of-doping-and-morphology
#3
Ting Yang, Jin Zheng, Qian Cheng, Yan Yan Hu, Candace K Chan
Composite polymer solid electrolytes (CPEs) containing ceramic fillers embedded inside a polymer-salt matrix show great improvements in Li+ ionic conductivity compared to the polymer electrolyte alone. Lithium lanthanum zirconate (Li7La3Zr2O12, LLZO) with garnet-type crystal structure is a promising solid Li+ conductor. We show that by incorporating only 5 wt% of ceramic filler comprising undoped, cubic-phase LLZO nanowires prepared by electrospinning, the room temperature ionic conductivity of a polyacrylonitrile-LiClO4-based composite is increased 3 orders of magnitude to 1...
June 9, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28593944/non-ising-and-chiral-ferroelectric-domain-walls-revealed-by-nonlinear-optical-microscopy
#4
Salia Cherifi-Hertel, Hervé Bulou, Riccardo Hertel, Grégory Taupier, Kokou Dodzi Honorat Dorkenoo, Christian Andreas, Jill Guyonnet, Iaroslav Gaponenko, Katia Gallo, Patrycja Paruch
The properties of ferroelectric domain walls can significantly differ from those of their parent material. Elucidating their internal structure is essential for the design of advanced devices exploiting nanoscale ferroicity and such localized functional properties. Here, we probe the internal structure of 180° ferroelectric domain walls in lead zirconate titanate (PZT) thin films and lithium tantalate bulk crystals by means of second-harmonic generation microscopy. In both systems, we detect a pronounced second-harmonic signal at the walls...
June 8, 2017: Nature Communications
https://www.readbyqxmd.com/read/28580142/enhanced-pyroelectric-and-piezoelectric-properties-of-pzt-with-aligned-porosity-for-energy-harvesting-applications
#5
Yan Zhang, Mengying Xie, James Roscow, Yinxiang Bao, Kechao Zhou, Dou Zhang, Chris R Bowen
This paper demonstrates the significant benefits of exploiting highly aligned porosity in piezoelectric and pyroelectric materials for improved energy harvesting performance. Porous lead zirconate (PZT) ceramics with aligned pore channels and varying fractions of porosity were manufactured in a water-based suspension using freeze-casting. The aligned porous PZT ceramics were characterized in detail for both piezoelectric and pyroelectric properties and their energy harvesting performance figures of merit were assessed parallel and perpendicular to the freezing direction...
April 14, 2017: Journal of Materials Chemistry. A, Materials for Energy and Sustainability
https://www.readbyqxmd.com/read/28543615/improved-image-quality-and-reduced-power-deposition-in-the-spine-at-3-t-using-extremely-high-permittivity-materials
#6
Kirsten Koolstra, Peter Börnert, Wyger Brink, Andrew Webb
PURPOSE: To explore the effect of using extremely high permittivity (εr ∼1,000) materials on image quality and power requirements of spine imaging at 3 T. THEORY AND METHODS: A linear array of high permittivity dielectric blocks made of lead zirconate titanate (PZT) was designed and characterized by electromagnetic simulations and experiments. Their effect on the transmit efficiency, receive sensitivity, power deposition, and diagnostic image quality was analyzed in vivo in 10 healthy volunteers...
May 22, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28541929/pressure-induced-structural-modifications-of-rare-earth-hafnate-pyrochlore
#7
Katlyn M Turner, Dylan R Rittman, Rachel A Heymach, Cameron L Tracy, Madison L Turner, Antonio F Fuentes, Wendy L Mao, Rodney C Ewing
Complex oxides with the pyrochlore (A2B2O7) and defect-fluorite ((A,B)4O7) structure-types undergo structural transformations under high-pressure. Rare-earth hafnates (A2Hf2O7) form the pyrochlore structure for A  =  La-Tb and the defect-fluorite structure for A  =  Dy-Lu. High-pressure transformations in A2Hf2O7 pyrochlore (A  =  Sm, Eu, Gd) and defect-fluorite (A  =  Dy, Y, Yb) were investigated up to ~50 GPa and characterized by in situ Raman spectroscopy and synchrotron x-ray diffraction (XRD)...
May 25, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28508876/post-supereruption-recovery-at-toba-caldera
#8
Adonara E Mucek, Martin Danišík, Shanaka L de Silva, Axel K Schmitt, Indyo Pratomo, Matthew A Coble
Large calderas, or supervolcanoes, are sites of the most catastrophic and hazardous events on Earth, yet the temporal details of post-supereruption activity, or resurgence, remain largely unknown, limiting our ability to understand how supervolcanoes work and address their hazards. Toba Caldera, Indonesia, caused the greatest volcanic catastrophe of the last 100 kyr, climactically erupting ∼74 ka. Since the supereruption, Toba has been in a state of resurgence but its magmatic and uplift history has remained unclear...
May 16, 2017: Nature Communications
https://www.readbyqxmd.com/read/28453970/on-chip-ultrasonic-manipulation-of-microparticles-by-using-the-flexural-vibration-of-a-glass-substrate
#9
Ryota Yamamoto, Daisuke Koyama, Mami Matsukawa
As biotechnology develops, techniques for manipulating and separating small particles such as cells and DNA are required in the life sciences. This paper investigates on-chip manipulation of microparticles in small channels by using ultrasonic vibration. The chip consists of a rectangular glass substrate with a cross-shaped channel (cross-section: 2.0×2.0mm(2)) and four lead zirconate titanate transducers attached to the substrate's four corners. To efficiently generate the flexural vibration mode on the chip, we used finite element analysis to optimize the configurations of the glass substrate and transducers...
December 15, 2016: Ultrasonics
https://www.readbyqxmd.com/read/28436860/effect-on-high-intensity-fields-of-a-tough-hydrophone-with-hydrothermal-pzt-thick-film-vibrator-and-titanium-front-layer
#10
Nagaya Okada, Shinichi Takeuchi
A novel tough hydrophone was fabricated by depositing hydrothermally synthesized lead zirconate titanate polycrystalline film on the back-side surface of a titanium plate. Our developed tough hydrophone resisted damage in a high-pressure field (15 MPa) at a focal point of a sinusoidal continuous wave driven by a concave high-intensity focused ultrasound (HIFU) transducer with up to 50 W of power input to the sound source. The hydrophone was suitable for the HIFU field, even though the hydrophone has a flat-shape tip of 3...
April 24, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28425964/enhancing-the-responsivity-of-uncooled-infrared-detectors-using-plasmonics-for-high-performance-infrared-spectroscopy
#11
Amr Shebl Ahmed, Hye Jin Kim, Jinsik Kim, Kyo Seon Hwang, Seonghwan Kim
A lead zirconate titanate (PZT;Pb(Zr0.52Ti0.48)O₃) layer embedded infrared (IR) detector decorated with wavelength-selective plasmonic crystals has been investigated for high-performance non-dispersive infrared (NDIR) spectroscopy. A plasmonic IR detector with an enhanced IR absorption band has been designed based on numerical simulations, fabricated by conventional microfabrication techniques, and characterized with a broadly tunable quantum cascade laser. The enhanced responsivity of the plasmonic IR detector at specific wavelength band has improved the performance of NDIR spectroscopy and pushed the limit of detection (LOD) by an order of magnitude...
April 20, 2017: Sensors
https://www.readbyqxmd.com/read/28425542/acceptor-doping-in-the-proton-conductor-srzro3
#12
Leigh Weston, A Janotti, X Y Cui, C Stampfl, C G Van de Walle
Perovskite zirconates such as SrZrO3 exhibit improved proton solubility and conductivity when doped with trivalent cations substituting at the Zr site. In this work, we present a detailed study of Sc and Y dopants in SrZrO3 based on first-principles, hybrid density-functional calculations. When substituting at the Zr site (ScZr, YZr), both dopants give rise to a single, deep acceptor level, where the neutral impurity forms a localized hole polaron state. The ε(0/-) charge transition levels are 0.60 eV and 0...
April 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28400602/first-direct-evidence-of-pan-african-orogeny-associated-with-gondwana-assembly-in-the-cathaysia-block-of-southern-china
#13
Longming Li, Shoufa Lin, Guangfu Xing, Yang Jiang, Jian He
Metamorphic zircon from a hornblendite in the South China Block (SCB) yield U-Pb age of 533 ± 7 Ma and Hf model ages from 900 to 1200 Ma. Geochemical and isotopic characteristics indicate that primary magma of the hornblendites was probably derived from an enriched asthenospheric mantle source. This Late Neoproterozoic-Cambrian (Pan-African) metamorphic event provides the first direct evidence that the SCB was an integral part of the Gondwana assembly. Combined with available geological data which show that the SCB has great affinity with India or Australia, the Pan-African metamorphic event most likely belongs to the eastern Kuunga orogeny...
April 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28389635/contrasting-granite-metallogeny-through-the-zircon-record-a-case-study-from-myanmar
#14
Nicholas J Gardiner, Chris J Hawkesworth, Laurence J Robb, Martin J Whitehouse, Nick M W Roberts, Christopher L Kirkland, Noreen J Evans
Granitoid-hosted mineral deposits are major global sources of a number of economically important metals. The fundamental controls on magma metal fertility are tectonic setting, the nature of source rocks, and magma differentiation. A clearer understanding of these petrogenetic processes has been forged through the accessory mineral zircon, which has considerable potential in metallogenic studies. We present an integrated zircon isotope (U-Pb, Lu-Hf, O) and trace element dataset from the paired Cu-Au (copper) and Sn-W (tin) magmatic belts in Myanmar...
April 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28371521/spray-dried-sodium-zirconate-a-rapid-absorption-powder-for-co2-capture-with-enhanced-cyclic-stability
#15
Faith Bamiduro, Guozhao Ji, Andy P Brown, Valerie A Dupont, Ming Zhao, Steven J Milne
Improved powders for capturing CO2 at high temperatures are required for H2 production using sorption-enhanced steam reforming. Here, we examine the relationship between particle structure and carbonation rate for two types of Na2 ZrO3 powders. Hollow spray-dried microgranules with a wall thickness of 100-300 nm corresponding to the dimensions of the primary acetate-derived particles gave about 75 wt % theoretical CO2 conversion after a process-relevant 5 min exposure to 15 vol % CO2 . A conventional powder prepared by solid-state reaction carbonated more slowly, achieving only 50 % conversion owing to a greater proportion of the reaction requiring bulk diffusion through the densely agglomerated particles...
April 3, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28349169/multispectroscopic-methodology-to-study-libyan-desert-glass-and-its-formation-conditions
#16
Leticia Gomez-Nubla, Julene Aramendia, Silvia Fdez-Ortiz de Vallejuelo, Ainhoa Alonso-Olazabal, Kepa Castro, Maria Cruz Zuluaga, Luis Ángel Ortega, Xabier Murelaga, Juan Manuel Madariaga
Libyan desert glass (LDG) is a melt product whose origin is still a matter of controversy. With the purpose of adding new information about this enigma, the present paper analyzes the inner part of LDG specimens and compares them with the results of LDG surfaces. An integrated analytical methodology was used combining different techniques such as Raman spectroscopy, in point-by-point and imaging modes, scanning electron microscopy with X-ray microanalysis (SEM-EDS), energy-dispersive micro X-ray fluorescence spectrometry (μ-EDXRF), electron probe micro analyzer (EPMA), and optical cathodoluminescence (Optical-CL)...
March 27, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28345655/large-electrocaloric-effect-in-relaxor-ferroelectric-and-antiferroelectric-lanthanum-doped-lead-zirconate-titanate-ceramics
#17
Biao Lu, Peilian Li, Zhenhua Tang, Yingbang Yao, Xingsen Gao, Wolfgang Kleemann, Sheng-Guo Lu
Both relaxor ferroelectric and antiferroelectric materials can individually demonstrate large electrocaloric effects (ECE). However, in order to further enhance the ECE it is crucial to find a material system, which can exhibit simultaneously both relaxor ferroelectric and antiferroelectric properties, or easily convert from one into another in terms of the compositional tailoring. Here we report on a system, in which the structure can readily change from antiferroelectric into relaxor ferroelectric and vice versa...
March 27, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28345044/continental-igneous-rock-composition-a-major-control-of-past-global-chemical-weathering
#18
Clément P Bataille, Amy Willis, Xiao Yang, Xiao-Ming Liu
The composition of igneous rocks in the continental crust has changed throughout Earth's history. However, the impact of these compositional variations on chemical weathering, and by extension on seawater and atmosphere evolution, is largely unknown. We use the strontium isotope ratio in seawater [((87)Sr/(86)Sr)seawater] as a proxy for chemical weathering, and we test the sensitivity of ((87)Sr/(86)Sr)seawater variations to the strontium isotopic composition ((87)Sr/(86)Sr) in igneous rocks generated through time...
March 2017: Science Advances
https://www.readbyqxmd.com/read/28338853/radiological-impacts-assessment-for-workers-in-ceramic-industry-in-serbia
#19
Nataša Todorovic, Dušan Mrda, Jan Hansman, Slavko Todorovic, Jovana Nikolov, Miodrag Krmar
Studies have been carried out to determine the natural radioactivity in some materials used in ceramic industry (zircon, zirkosil, Zircobit MO/S, zircon silicate, zirklonil frit, hematite, bentonite, wollastonite, raw kaolin, kaolinized granite, sileks ball, feldspar, pigment, white base serigraphic, engobe) and their associated radiation hazard. The external hazard index, Hex, values, radium equivalent activity, Raeq, total absorbed dose rates, D and annual effective dose, De were derived for all measured materials and compared with the recommended values to assess the external radiation hazards to workers who worked in ceramic industries in Serbia...
March 3, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28333626/temperature-dependence-of-domain-contributions-as-a-function-of-ageing-in-soft-and-hard-lead-zirconate-titanate-piezoelectric-ceramics
#20
Sayyed A Qaisar, Timothy P Comyn, Andrew J Bell
The stress and temperature dependence of three different PZT ceramics have been measured at 48 hours and 1 month after poling. The data were fitted to a modified Rayleigh law in which a negative quadratic stress term accounts for a saturation of the domain wall contributions at higher stress. The relative changes to the fitting parameters can be explained by the materials possessing differences in the concentration of orientable defect dipoles, but with similar distributions of relaxation time constants.
March 22, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
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