keyword
MENU ▼
Read by QxMD icon Read
search

Silicate

keyword
https://www.readbyqxmd.com/read/28821055/improvement-of-silicate-cement-properties-with-bacterial-cellulose-powder-addition-for-applications-in-dentistry
#1
Georgeta Voicu, Sorin-Ion Jinga, Bogdan-Gabriel Drosu, Cristina Busuioc
The goal of this paper was to synthesize a new family of composites starting from mineral binder powders and biocellulose membranes, with applications in endodontics. An important achievement consisted in the crushing of biocellulose 3D structure in a polygranular powder via an hydrothermal treatment. Afterwards, the polymer powder was mixed with silicate cement powders synthesized through the sol-gel technique. The resulting hybrid materials were investigated by thermal analysis, X-ray diffraction, scanning electron microscopy and mechanical measurements...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28819724/hydrogeochemistry-and-water-quality-of-the-kordkandi-duzduzan-plain-nw-iran-application-of-multivariate-statistical-analysis-and-pos-index
#2
Shahla Soltani, Asghar Asghari Moghaddam, Rahim Barzegar, Naeimeh Kazemian, Evangelos Tziritis
Kordkandi-Duzduzan plain is one of the fertile plains of East Azarbaijan Province, NW of Iran. Groundwater is an important resource for drinking and agricultural purposes due to the lack of surface water resources in the region. The main objectives of the present study are to identify the hydrogeochemical processes and the potential sources of major, minor, and trace metals and metalloids such as Cr, Mn, Cd, Fe, Al, and As by using joint hydrogeochemical techniques and multivariate statistical analysis and to evaluate groundwater quality deterioration with the use of PoS environmental index...
August 18, 2017: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/28817774/efficient-concentration-of-indium-iii-from-aqueous-solution-using-layered-silicates
#3
Natthawut Homhuan, Sareeya Bureekaew, Makoto Ogawa
A synthetic layered alkali silicate, magadiite, and a natural montmorillite were found to concentrate indium(III) ion from aqueous solution by ion exchange reactions. The adsorption was examined by the reaction between silicates and aqueous solution of indium(III) chloride of different concentration at room temperature for 10 min. The adsorption isotherms were H type, indicating strong interactions between the silicates and indium(III) ion. The maximum adsorbed indium(III) amount for magadiite was quite high, ca...
August 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28815932/polymer-based-hybrid-nanocomposites-a-progress-toward-enhancing-interfacial-interaction-and-tailoring-advanced-applications
#4
REVIEW
Chang-Sik Ha
Organic/inorganic hybrid nanocomposites, in particular polymer based hybrid nanocomposites, constitute emerging advanced materials since they combine unique properties from the inorganic and organic (i. e. polymeric) components. We investigated three different hybrid nanocomposites depending on dimensions of the dispersed phase in the nanometer range,; polymer-layered silicate (PLS) nanocomposites where polymers are mixed with layered silicates, polymer/graphene oxide hybrid nanocomposites, and polymer hybrid nanocomposites with reinforcing polymers with isodimensional phases of inorganic silicas using sol-gel reactions...
August 17, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28814651/n2-fixing-tropical-legume-evolution-a-contributor-to-enhanced-weathering-through-the-cenozoic
#5
REVIEW
Dimitar Z Epihov, Sarah A Batterman, Lars O Hedin, Jonathan R Leake, Lisa M Smith, David J Beerling
Fossil and phylogenetic evidence indicates legume-rich modern tropical forests replaced Late Cretaceous palm-dominated tropical forests across four continents during the early Cenozoic (58-42 Ma). Tropical legume trees can transform ecosystems via their ability to fix dinitrogen (N2) and higher leaf N compared with non-legumes (35-65%), but it is unclear how their evolutionary rise contributed to silicate weathering, the long-term sink for atmospheric carbon dioxide (CO2). Here we hypothesize that the increasing abundance of N2-fixing legumes in tropical forests amplified silicate weathering rates by increased input of fixed nitrogen (N) to terrestrial ecosystems via interrelated mechanisms including increasing microbial respiration and soil acidification, and stimulating forest net primary productivity...
August 16, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28812880/an-exceptionally-narrow-band-gap-%C3%A2-4-ev-silicate-predicted-in-the-cubic-perovskite-structure-basio3
#6
Hidenori Hiramatsu, Hitoshi Yusa, Ryo Igarashi, Yasuo Ohishi, Toshio Kamiya, Hideo Hosono
The electronic structures of 35 A(2+)B(4+)O3 ternary cubic perovskite oxides, including their hypothetical chemical compositions, were calculated by a hybrid functional method with the expectation that peculiar electronic structures and unique carrier transport properties suitable for semiconductor applications would be hidden in high-symmetry cubic perovskite oxides. We found unique electronic structures of Si-based oxides (A = Mg, Ca, Sr, and Ba, and B = Si). In particular, the unreported cubic BaSiO3 has a very narrow band gap (4...
August 16, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28811588/dynamics-of-nano-confined-water-in-portland-cement-comparison-with-synthetic-c-s-h-gel-and-other-silicate-materials
#7
Guido Goracci, Manuel Monasterio, Helen Jansson, Silvina Cerveny
The dynamics of water confined in cement materials is still a matter of debate in spite of the fact that water has a major influence on properties such as durability and performance. In this study, we have investigated the dynamics of water confined in Portland cement (OPC) at different curing ages (3 weeks and 4 years after preparation) and at three water-to-cement ratios (w/c, 0.3, 0.4 and 0.5). Using broadband dielectric spectroscopy, we distinguish four different dynamics due to water molecules confined in the pores of different sizes of cements...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28811021/quantitative-analysis-of-major-and-trace-elements-in-nh4hf2-modified-silicate-rock-powders-by-laser-ablation-inductively-coupled-plasma-mass-spectrometry
#8
Wen Zhang, Zhaochu Hu, Yongsheng Liu, Wenwu Yang, Haihong Chen, Shenghong Hu, Hongyan Xiao
In this paper, we described a NH4HF2 digestion method as sample preparation for the rapid determination of major and trace elements in silicate rocks using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). Sample powders digested by NH4HF2 at 230 °C for 3 h form ultrafine powders with a typical grain size d80 < 8.5 μm, and various silicate rocks have a consistent grain morphology and size, allowing us to produce pressed powder pellets that have excellent cohesion and homogeneity suitable for laser ablation micro-analysis without the addition of binder...
August 29, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28808463/micro-push-out-bond-strength-and-bioactivity-analysis-of-a-bioceramic-root-canal-sealer
#9
Ceci Nunes Carvalho, Renata Grazziotin-Soares, George Táccio de Miranda Candeiro, Luis Gallego Martinez, Juliana Pereira de Souza, Patrícia Santos Oliveira, José Bauer, Giulio Gavini
INTRODUCTION: Bioactive endodontic sealers have been developed to improve the quality of root canal obturation. EndoSequence Bioceramic (BC) Sealer is amongst calcium silicate-based materials recently developed for permanent root canal filling. The objective of this study was to evaluate the bioactivity of BC Sealer and its micro push-out bond strength to dentin compared to AH-Plus (AH) sealer. METHODS AND MATERIALS: To perform the micro push-out test, 24 root canals of mandibular premolars were instrumented and divided into two groups (n=12)...
2017: Iranian Endodontic Journal
https://www.readbyqxmd.com/read/28806680/sequestration-of-aluminium-iii-by-different-natural-and-synthetic-organic-and-inorganic-ligands-in-aqueous-solution
#10
Paola Cardiano, Rosalia Maria Cigala, Francesco Crea, Fausta Giacobello, Ottavia Giuffrè, Anna Irto, Gabriele Lando, Silvio Sammartano
The speciation of Al(3+) in aqueous solutions containing organic and inorganic ligands important from a biological (citrate (Cit(3-)), gluconate (Gluc(-)), lactate (Lac(-)), silicate (H2SiO4(2-)), carbonate (CO3(2-)), fluoride (F(-))) and industrial (Gantrez(®); polymethyl-vinyl-ether-co-maleic acids; GTZ S95 and GTZ AN169) point of view is reported. The stability constants of Al(3+)/L(z-) complexes (L(z-) = ligand with z(-) charge) were determined by potentiometry at T = 298.15 K and 0.10 ≤ I/M ≤ 1...
August 7, 2017: Chemosphere
https://www.readbyqxmd.com/read/28804677/haloselective-cross-coupling-via-ni-photoredox-dual-catalysis
#11
Kingson Lin, Rebecca J Wiles, Christopher B Kelly, Geraint H M Davies, Gary A Molander
The chemoselective functionalization of polyfunctional aryl linchpins is crucial for rapid diversification. Although well-explored for Csp(2) and Csp nucleophiles, the chemoselective introduction of Csp(3) groups remains notoriously difficult and is virtually undocumented using Ni catalysts. To fill this methodological gap, a "haloselective" cross-coupling process of arenes bearing two halogens, I and Br, using ammonium alkylbis(catecholato)silicates, has been developed. Utilizing Ni/photoredox dual catalysis, Csp(3) -Csp(2) bonds can be forged selectively at the iodine-bearing carbon of bromo(iodo)arenes...
August 4, 2017: ACS Catalysis
https://www.readbyqxmd.com/read/28802247/effect-of-lead-speciation-on-its-oral-bioaccessibility-in-surface-dust-and-soil-of-electronic-wastes-recycling-sites
#12
Takashi Fujimori, Masaya Taniguchi, Tetsuro Agusa, Kenji Shiota, Masaki Takaoka, Aya Yoshida, Atsushi Terazono, Florencio C Ballesteros, Hidetaka Takigami
We measured bioaccessible lead (Pb) in simulated gastrointestinal fluids containing Pb-contaminated soil or dust from electronic waste (e-waste) recycling sites to assess the risk of Pb ingestion. The physiologically based extraction test (PBET) was used as in vitro bioaccessibility assay. Pb speciation was determined using X-ray absorption spectroscopy. The total Pb concentrations in dusts (n=8) and soils (n=4) were in the range of 1630-131,000 and 239-7800mg/kg, respectively. Metallic Pb, a common component of e-waste, was ubiquitous in the samples...
August 4, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28799741/early-assessment-and-correlations-of-nanoclay-s-toxicity-to-their-physical-and-chemical-properties
#13
Alixandra Wagner, Andrew White, Todd A Stueckle, Derrick Banerjee, Konstantinos A Sierros, Yon Rojanasakul, Sushant Agarwal, Rakesh K Gupta, Cerasela Zoica Dinu
Nanoclays' functionalization with organic modifiers increases their individual barrier properties, thermal stability, and mechanical properties and allows for ease of implementation in food packaging materials or medical devices. Previous reports have showed that while organic modifiers integration between the layered mineral silicates leads to nanoclays with different degrees of hydrophobicity that become easily miscible in polymers, they could also pose possible effects at inhalation or ingestion routes of exposure...
August 11, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28799215/secondary-structure-and-dynamics-study-of-the-intrinsically-disordered-silica-mineralizing-peptide-p5-s3-during-silicic-acid-condensation-and-silica-decondensation
#14
Christian Zerfaß, Garry W Buchko, Wendy J Shaw, Stephan Hobe, Harald Paulsen
The silica forming repeat R5 of sil1 from Cylindrotheca fusiformis was the blueprint for the design of P5 S3 , a 50-residue peptide which can be produced in large amounts by recombinant bacterial expression. It contains five protein kinase A target sites and is highly cationic due to 10 lysine and 10 arginine residues. In the presence of supersaturated orthosilicic acid P5 S3 enhances silica-formation whereas it retards the dissolution of amorphous silica (SiO2 ) at globally undersaturated concentrations. The secondary structure of P5 S3 during these two processes was studied by circular dichroism (CD) spectroscopy, complemented by nuclear magnetic resonance (NMR) spectroscopy of the peptide in the absence of silicate...
August 11, 2017: Proteins
https://www.readbyqxmd.com/read/28798127/a-unified-continental-thickness-from-seismology-and-diamonds-suggests-a-melt-defined-plate
#15
Saikiran Tharimena, Catherine Rychert, Nicholas Harmon
Thick, rigid continents move over the weaker underlying mantle, although geophysical and geochemical constraints on the exact thickness and defining mechanism of the continental plates are widely discrepant. Xenoliths suggest a chemical continental lithosphere ~175 kilometers thick, whereas seismic tomography supports a much thicker root (>250 kilometers) and a gradual lithosphere-asthenosphere transition, consistent with a thermal definition. We modeled SS precursor waveforms from continental interiors and found a 7 to 9% velocity drop at depths of 130 to 190 kilometers...
August 11, 2017: Science
https://www.readbyqxmd.com/read/28797942/high-calcium-fly-ash-geopolymer-stabilized-lateritic-soil-and-granulated-blast-furnace-slag-blends-as-a-pavement-base-material
#16
Itthikorn Phummiphan, Suksun Horpibulsuk, Runglawan Rachan, Arul Arulrajah, Shui-Long Shen, Prinya Chindaprasirt
Granulated Blast Furnace Slag (GBFS) was used as a replacement material in marginal lateritic soil (LS) while class C Fly Ash (FA) was used as a precursor for the geopolymerization process to develop a low-carbon pavement base material at ambient temperature. Unconfined Compression Strength (UCS) tests were performed to investigate the strength development of geopolymer stabilized LS/GBFS blends. Scanning Electron Microscopy and X-ray Diffraction analysis were undertaken to examine the role of the various influencing factors on UCS development...
July 31, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28796180/formation-and-properties-of-laser-induced-periodic-surface-structures-on-different-glasses
#17
Stephan Gräf, Clemens Kunz, Frank A Müller
The formation and properties of laser-induced periodic surface structures (LIPSS) was investigated on different technically relevant glasses including fused silica, borosilicate glass, and soda-lime-silicate glass under irradiation of fs-laser pulses characterized by a pulse duration τ = 300 fs and a laser wavelength λ = 1025 nm. For this purpose, LIPSS were fabricated in an air environment at normal incidence with different laser peak fluence, pulse number, and repetition frequency. The generated structures were characterized by using optical microscopy, scanning electron microscopy, focused ion beam preparation and Fast-Fourier transformation...
August 10, 2017: Materials
https://www.readbyqxmd.com/read/28794848/bioactive-calcium-phosphate-based-glasses-and-ceramics-and-their-biomedical-applications-a-review
#18
Md Towhidul Islam, Reda M Felfel, Ensanya A Abou Neel, David M Grant, Ifty Ahmed, Kazi M Zakir Hossain
An overview of the formation of calcium phosphate under in vitro environment on the surface of a range of bioactive materials (e.g. from silicate, borate, and phosphate glasses, glass-ceramics, bioceramics to metals) based on recent literature is presented in this review. The mechanism of bone-like calcium phosphate (i.e. hydroxyapatite) formation and the test protocols that are either already in use or currently being investigated for the evaluation of the bioactivity of biomaterials are discussed. This review also highlights the effect of chemical composition and surface charge of materials, types of medium (e...
January 2017: Journal of Tissue Engineering
https://www.readbyqxmd.com/read/28782027/gallium-isotopic-evidence-for-extensive-volatile-loss-from-the-moon-during-its-formation
#19
Chizu Kato, Frédéric Moynier
The distribution and isotopic composition of volatile elements in planetary materials holds a key to the characterization of the early solar system and the Moon's formation. The Moon and Earth are chemically and isotopically very similar. However, the Moon is highly depleted in volatile elements and the origin of this depletion is still debated. We present gallium isotopic and elemental measurements in a large set of lunar samples to constrain the origin of this volatile depletion. We show that while Ga has a geochemical behavior different from zinc, both elements show a systematic enrichment in the heavier isotopes in lunar mare basalts and Mg-suite rocks compared to the silicate Earth, pointing to a global-scale depletion event...
July 2017: Science Advances
https://www.readbyqxmd.com/read/28777608/topological-control-on-the-structural-relaxation-of-atomic-networks-under-stress
#20
Mathieu Bauchy, Mengyi Wang, Yingtian Yu, Bu Wang, N M Anoop Krishnan, Enrico Masoero, Franz-Joseph Ulm, Roland Pellenq
Upon loading, atomic networks can feature delayed irreversible relaxation. However, the effect of composition and structure on relaxation remains poorly understood. Herein, relying on accelerated molecular dynamics simulations and topological constraint theory, we investigate the relationship between atomic topology and stress-induced structural relaxation, by taking the example of creep deformations in calcium silicate hydrates (C─S─H), the binding phase of concrete. Under constant shear stress, C─S─H is found to feature delayed logarithmic shear deformations...
July 21, 2017: Physical Review Letters
keyword
keyword
37701
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"