scholarly journals Demineralization, Collagen Modification and Remineralization Degree of Human Dentin after EDTA and Citric Acid Treatments

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 25 ◽  
Author(s):  
Maria Gandolfi ◽  
Paola Taddei ◽  
Anna Pondrelli ◽  
Fausto Zamparini ◽  
Carlo Prati ◽  
...  
Keyword(s):  
Citric Acid ◽  
Ethylenediaminetetraacetic Acid ◽  
Environmental Scanning Electron Microscopy ◽  
Chelating Agent ◽  
Environmental Scanning ◽  
X Ray ◽  
Before And After ◽  
Human Dentin ◽  
Mineral Components ◽  
Mineralization Degree

The aim of the study was to investigate the effects of several decalcifying agents used as irrigant solutions in endodontic treatment on collagen and mineral components of dentin. Coronal dentin discs from five caries-free human third molars with a smear layer were treated for one minute with a chelating solution (1% Ethylenediaminetetraacetic acid (EDTA), 10% EDTA, 17% EDTA, 10% citric acid). Mineralization degree (Ca/N and P/N atomic ratios, IR Iapatite/Iamide II and I1410(carbonate)/I554(phosphate) spectroscopic ratios) and possible collagen rearrangements (collagen infrared (IR) amide II e III shifts) were evaluated by environmental scanning electron microscopy (ESEM)/energy dispersive X-ray spectroscopy (EDX) and IR spectroscopy before and after treatment (T0) and after ageing (T24h and T2m) in simulated body fluid (SBF). At T0, analysis showed that the highest demineralizing effect was achieved using a 10% citric acid solution and 10% EDTA, while the smallest effect was observed when using 17% EDTA. No significant collagen modifications were detected upon treatment with 1% EDTA, while subtle changes were observed after the other treatments. At T24h or T2m, analyses showed the highest remineralization values for 1% EDTA and the lowest for 10% citric acid, mainly at T2m. The samples treated with 17% EDTA showed slight collagen rearrangements upon remineralization. In conclusion, the highest demineralizing effect was observed for 10% EDTA and 10% citric acid. Collagen rearrangement was found for all the treatments except for 1% EDTA. The highest remineralization capability in SBF values was recorded for 1% EDTA and the lowest for 10% citric acid. A slight collagen rearrangement upon remineralization was still present in 17% EDTA-treated samples. Clinical use as a chelating agent in the endodontic therapy of citric acid and concentrated EDTA solutions should be reconsidered.

scholarly journals Effect of Alkaline Degumming on Structure and Properties of Lotus Fibers at Different Growth Period

2015 ◽  
Vol 10 (1) ◽  
pp. 155892501501000 ◽  
Author(s):  
Fengyan Li ◽  
Hongjun Fu
Keyword(s):  
Environmental Scanning Electron Microscopy ◽  
Growth Period ◽  
Bond Rupture ◽  
Environmental Scanning ◽  
Structure And Properties ◽  
Breaking Force ◽  
X Ray Diffraction ◽  
Elongation At Break ◽  
X Ray ◽  
Before And After

Lotus fibers are pulled from different period of lotus root. Alkaline was used as degumming agent to remove non-cellulose impurities of lotus fibers. Environmental scanning electron microscopy (ESEM), X-ray diffraction (XRD) and FTIR were used to characterize surface morphology and microscopic structure of lotus fibers before and after degumming. The effect of alkaline degumming on tensile properties of lotus fibers is investigated. The results show that impurities remove, hydrogen bond rupture, and crystallinity of partly armorphous chain occur during alkaline degumming. All of these changes play roles in influencing fiber tensile breaking force and elongation at break.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

Detector strategies for environmental scanning electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1296-1297
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
High Vacuum ◽  
Environmental Scanning Electron Microscopy ◽  
Charge Carriers ◽  
Environmental Scanning ◽  
Surface Information ◽  
X Ray ◽  
Detector Electrode ◽  
Electrons And Ions ◽  
Low Energy Electrons ◽  
Environmental Sem

Environmental SEM operate at specimen chamber pressures of ∼20 torr (2.7 kPa) allowing stabilization of liquid water at room temperature, working on rugged insulators, and generation of an environmental secondary electron (ESE) signal. All signals available in conventional high vacuum instruments are also utilized in the environmental SEM, including BSE, SE, absorbed current, CL, and X-ray. In addition, the ESEM allows utilization of the flux of charge carriers as information, providing exciting new signal modes not available to BSE imaging or to conventional high vacuum SEM.In the ESEM, at low vacuum, SE electrons are collected with a “gaseous detector”. This detector collects low energy electrons (and ions) with biased wires or plates similar to those used in early high vacuum SEM for SE detection. The detector electrode can be integrated into the first PLA or positioned at any other place resulting in a versatile system that provides a variety of surface information.

scholarly journals Iterative regularity and parent-offspring growth mold of stable grain array in bismuth silicate micro-crystals

2011 ◽  
Vol 43 (1) ◽  
pp. 105-112
Author(s):  
Z.G. Zhang ◽  
X.F. Wang ◽  
Q.Q. Tian
Keyword(s):  
Environmental Scanning Electron Microscopy ◽  
Morphological Properties ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Bismuth Silicate ◽  
X Ray ◽  
Offspring Growth ◽  
Line Spacing ◽  
Array Structure ◽  
Sintering Method

Bismuth silicate micro-crystals with grain array structure were prepared by sintering method under atmosphere pressure. The samples were characterized for structural and surface morphological properties by X-ray diffraction (XRD) and Environmental scanning electron microscopy (ESEM). The result shows that stable grain arrays grow by iterative mode. If a stable grain array eliminates, a new stable grain array will generate. In a stable parent array, an offspring array may generate after the corresponding partial elimination of its parent array. If one part of an offspring array stops growing, it will be as a new parent array, and then its offspring grain array will create. The sum of the lengths of an offspring array and the corresponding eliminated part of its parent array is equal to the length of the next eliminated part of its parent array. It means the growth rate of an offspring array is equal to that of the corresponding survived part of its parent array. There is a highly correlation between grain array length and average grain line spacing. It means that larger average grain line spacing corresponds to the stable grain array with lager length. When average grain line spacing increases 1?m, the corresponding array length will increase approximately 7.6?m.

The structure and chemical layering of Proterozoic stromatolites in the Mojave Desert

2015 ◽  
Vol 14 (3) ◽  
pp. 517-526 ◽  
Author(s):  
Susanne Douglas ◽  
Meredith E. Perry ◽  
William J. Abbey ◽  
Zuki Tanaka ◽  
Bin Chen ◽  
...  
Keyword(s):  
Elemental Analysis ◽  
Mojave Desert ◽  
Environmental Scanning Electron Microscopy ◽  
Xrd Analysis ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Mars Rover ◽  
X Ray ◽  
High K ◽  
Representative Samples

AbstractThe Proterozoic carbonate stromatolites of the Pahrump Group from the Crystal Spring formation exhibit interesting layering patterns. In continuous vertical formations, there are sections of chevron-shaped stromatolites alternating with sections of simple horizontal layering. This apparent cycle of stromatolite formation and lack of formation repeats several times over a vertical distance of at least 30 m at the locality investigated. Small representative samples from each layer were taken and analysed using X-ray diffraction (XRD), X-ray fluorescence (XRF), environmental scanning electron microscopy – energy dispersive X-ray spectrometry, and were optically analysed in thin section. Optical and spectroscopic analyses of stromatolite and of non-stromatolite samples were undertaken with the objective of determining the differences between them. Elemental analysis of samples from within each of the four stromatolite layers and the four intervening layers shows that the two types of layers are chemically and mineralogically distinct. In the layers that contain stromatolites the Ca/Si ratio is high; in layers without stromatolites the Ca/Si ratio is low. In the high Si layers, both K and Al are positively correlated with the presence and levels of Si. This, together with XRD analysis, suggested a high K-feldspar (microcline) content in the non-stromatolitic layers. This variation between these two types of rocks could be due to changes in biological growth rates in an otherwise uniform environment or variations in detrital influx and the resultant impact on biology. The current analysis does not allow us to choose between these two alternatives. A Mars rover would have adequate resolution to image these structures and instrumentation capable of conducting a similar elemental analysis.

Performance Evaluation of BRA Modified Asphalt Mastic Based on Analysis of Microstructure and Rheological Mechanics Property

2011 ◽  
Vol 243-249 ◽  
pp. 4119-4124 ◽  
Author(s):  
Long Wen ◽  
Xiao Jiang Wang ◽  
Hao Liu ◽  
Hao Xiang Wu ◽  
Bao Lin Cui ◽  
...  
Keyword(s):  
High Temperature ◽  
Environmental Scanning Electron Microscopy ◽  
Temperature Stability ◽  
High Viscosity ◽  
Environmental Scanning ◽  
High Temperature Stability ◽  
X Ray ◽  
Modified Asphalt ◽  
Asphalt Mastic ◽  
Performance Grade

Buton rock asphalt (BRA) is possessed of both performance and economic advantages. In order to reveal the modification mechanism, X-ray diffraction experiment (XRD), X-ray fluorescence spectrum analysis and environmental scanning electron microscopy experiment (ESEM) are used to study on microstructure of BRA in this paper. It demonstrates that BRA can extremely adsorb free bitumen due to abundant microscopic pores, which consists of 70~80 percent Buton rock (BR) minerals and 20~30 percent pure rock asphalt (RA). RA with high viscosity is strongly adsorbed internal and outer of the surface of BR, which has high alkaline pH, high crystallization and strong surface activity. Then a special microstructure named “RA~BR” blend with stable property and strong spalling-resistance capability develops. Meanwhile, dynamic stability rheology test (DSR) is employed to study on the rheological mechanics property of BRA modified asphalt mastic. The high temperature performance grade (PG) level of BRA modified asphalt mastic with different mixing content is determined. The reasonable mixing content of BRA in matrix asphalt is 20~30 percent. The research proves that BRA modified asphalt possesses wonderful high temperature stability and has broad prospects for pavement application.

Applications of Environmental Scanning Electron Microscopy in Art Conservation and Archaeology

1990 ◽  
Vol 185 ◽  
Author(s):  
Dusan Stulik ◽  
Eric Doehne
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Micrographs ◽  
New Technology ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Art Conservation ◽  
Pilot Studies ◽  
X Ray ◽  
Scanning Electron

AbstractThe principles of Environmental Scanning Electron Microscopy (E-SEM) are explained and discussed. The performance of the E-SEM compares favorably with the performance of traditional SEM instruments. This new technology has significant advantages in art conservation and archaeology. In this paper we describe several pilot studies which explored potential uses of the E-SEM. Electron micrographs recorded from moist, outgassing, and difficult to coat samples are presented, together with X-ray spectra recorded from uncoated samples of electrically nonconductive materials.

Evaluation of Pulsed Laser Deposited Li4Ti5O12 Thin Film Anodes by CV and EIS

2013 ◽  
Vol 743-744 ◽  
pp. 13-19 ◽  
Author(s):  
Jian Qiu Deng ◽  
Zhou Guang Lu ◽  
Chi Yuen Chung ◽  
Zhong Min Wang ◽  
Huai Ying Zhou
Keyword(s):  
Thin Film ◽  
Electrochemical Impedance ◽  
Discharge Rate ◽  
Pulsed Laser ◽  
Environmental Scanning Electron Microscopy ◽  
Cycling Performance ◽  
Laser Deposition ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
X Ray

Li4Ti5O12thin film anodes were prepared successfully using pulsed laser deposition technique. The thin films were characterized by X-ray diffraction and environmental scanning electron microscopy. The effects of thickness and scan rate on the electrochemical properties of Li4Ti5O12thin film electrodes were discussed in detail. The thin film anodes deliver favorable capacity and excellent cycling performance. The discharge capacity maintains at 141 mAhg-1after 20 cycles at 1C charge-discharge rate for the thin film anodes deposited for 20 minutes. The charge-transfer resistances were also investigated by electrochemical impedance spectroscopy.

scholarly journals A sol-gel synthesis, characterization and in vitro bioactivity of binary, ternary and quaternary bioglasses with high mechanical strength

2020 ◽  
Vol 10 (4) ◽  
pp. 310-318
Author(s):  
Sara Bouhazma ◽  
Imane Adouar ◽  
Sanae Chajri ◽  
Smaiel Herradi ◽  
Mohamed Khaldi ◽  
...  
Keyword(s):  
Sol Gel ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
In Vitro Tests ◽  
In Vitro Bioactivity ◽  
X Ray Diffraction ◽  
High Mechanical Strength ◽  
X Ray ◽  
Sol Gel Synthesis

Bioactive powders of the binary SiO2-CaO, ternary SiO2-CaO-P2O5 and quaternary systems SiO2-CaO-P2O5-Na2O/Mg2O were synthesized using a sol-gel route. The gels were converted into bioglasses powders by heat treatments at the temperature of 700°C. The resulting materials were characterized by X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Environmental Scanning Electron Microscopy (ESEM) and in vitro bioactivity in acellular Simulated Body Fluid (SBF). The in vitro tests showed that the samples had good apatite-forming ability. Glasses doped with sodium and magnesium show good results in terms of bioactivity and mechanical properties. The results showed that the quaternary glass SiO2-CaO-P2O5-Na2O containing Na is the most bioactive, only 6 hours after its immersion in SBF; a layer of hydroxycarbonated apatite (HAC) was deposited on the glass and compressive strength of up to 233.08 MPa with a porosity of 11.02%, due to the presence of the Na2Ca2Si3O9 phase. Magnesium also affects bioactivity because it has improved from binary to ternary to quaternary doped with magnesium, bioactive from 12h of contact with the SBF.

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