scholarly journals Analysis of the Color and Fluorescence Alterations of Enamel and Dentin Treated With Hydrogen Peroxide

2015 ◽  
Vol 26 (5) ◽  
pp. 514-518 ◽  
Author(s):  
Taciana Marco Ferraz Caneppele ◽  
Carlos Rocha Gomes Torres ◽  
Eduardo Bresciani
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Characterization ◽  
Chemical Components ◽  
Whitening Effect ◽  
Color Changes ◽  
Repeated Analysis ◽  
Direct Fluorescence ◽  
Tooth Dentin ◽  
Bovine Enamel

Abstract: The aim of this study was to evaluate the effect of hydrogen peroxide whitening on fluorescence and color of bovine enamel and dentin. Twenty five dentin discs and 25 enamel discs, with 6 mm diameter and 1 mm thick, were obtained. Direct fluorescence (spectrofluorophotometry) and color (spectrophotometry) were assessed. After fluorescence and color baseline measurements, specimens were immersed in a 35% hydrogen peroxide (HP) solution for 1 h. This procedure was repeated after 7 days. Final fluorescence and color measurements were performed after the second immersion. Chemical characterization of 5 additional specimens was also performed. Data were submitted to repeated analysis of variance and Tukey´s test for fluorescence and unpaired t-test for color and chemical components (p<0.05). Fluorescence decreased significantly in dentin specimens after whitening. Enamel presented lower fluorescence than dentin at baseline, but this parameter did not decrease after whitening. Color changes were observed for both substrates, with significantly greater whitening effect in dentin (ΔE=10.37) (p<0.001). Whitening by hydrogen peroxide induced significant decrease in fluorescence of tooth dentin and promoted significant color changes in dentin and enamel with more accentuated outcomes in dentin.

scholarly journals GC-MS Chemical Characterization of Main Components of Smilax Domingensis Wild. in Cuba

2018 ◽  
Vol 5 (4) ◽  
pp. 79 ◽  
Author(s):  
Pilar A. Soledispa ◽  
José González ◽  
Armando Cuéllar ◽  
Julio Pérez ◽  
Max Monan
Keyword(s):  
Mass Spectra ◽  
Chemical Constituents ◽  
Chemical Characterization ◽  
Ethanolic Extract ◽  
Chemical Compounds ◽  
Chemical Components ◽  
Analytical Technique ◽  
Main Components ◽  
First Time

A preliminary chemical characterization of main components of ethanolic extract with dried rhizomes of Smilax domingensis Wid. that grow in Cuba was done using a GCMS-QP2010 Ultra Shimadzu and the mass spectra of the compounds found in the extract was matched with the National Institute of Standards and Technology (NIST) library. After sample derivatization 125 chemical compounds were registered by the equipment and from them, 35 different chemical components were characterized and reported for the first time from this part of the plant in our country. The results demonstrate the developed method could be employed as a rapid and versatile analytical technique for identification of chemical constituents and quality control of Smilax domingensis.

Synthesis and Characterization of New Dibenzo[b, e]Thiepine Derivatives. I

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Camelia Elena Stecoza ◽  
Miron Teodor Caproiu ◽  
Constantin Draghici ◽  
Corina Ilie ◽  
Ileana Cornelia Chirita
Keyword(s):  
Hydrogen Peroxide ◽  
Spectral Analysis ◽  
Benzoic Acid ◽  
Potassium Salt ◽  
Polyphosphoric Acid ◽  
Chemical Characterization ◽  
Synthesis And Characterization ◽  
Acid Chlorides ◽  
New Compounds

The aim of the present paper was the synthesis and chemical characterization of some original compounds with dibenzo[b,e]thiepine structure. The synthesis of the new compounds was performed in several stages. Thus, by reaction of phtalide with thiophenol potassium salt, we obtained the 2-phenylthiomethyl-benzoic acid. The acid was cyclized with polyphosphoric acid to the desired 6,11-dihydrodibenzo[b,e]thiepin-11(6H)-one, converted afterwards to the corresponding oxime and subsequently to the O-acyloximino-dibenzo[b,e]thiepins by acylation with various substituted benzoic acid chlorides. The oxidation of O-acyloximino-dibenzo[b,e]thiepins with hydrogen peroxide afforded the corresponding sulfones. The new compounds, four O-acyl-oximino-dibenzo[b,e]thiepins, and four O-acyl-oximino-dibenzo[b,e]thiepin-5,5-dioxides, have been characterized by their physical constants (melting point, solubility) and their structures and purity were confirmed by elemental analysis, and spectral analysis (IR, 1H-NMR, 13C-NMR).

scholarly journals ANATOMICAL AND CHEMICAL PROPERTIES OF JUVENILE Schizolobium amazonicum WOOD

2018 ◽  
Vol 42 (3) ◽  
Author(s):  
Graziela Baptista Vidaurre ◽  
Benedito Rocha Vital ◽  
Jorge Luiz Colodette ◽  
Angélica de Cássia Oliveira ◽  
João Gabriel Missia da Silva ◽  
...  
Keyword(s):  
Chemical Elements ◽  
Chemical Properties ◽  
Chemical Characterization ◽  
Tree Age ◽  
Chemical Components ◽  
Cellulose Content ◽  
Anatomical Characteristics ◽  
Effect Of Age ◽  
High Cellulose

ABSTRACT The objective of this study was to determine the effects of tree age and of pith-bark and base-top positions on anatomical characteristics, and the effect of age on the chemical components of Schizolobium amazonicum (Paricá wood). The material was obtained from commercial plantations in the states of Maranhão and Pará with ages of 5, 7, 9 and 11 years. The first three logs (2.7 m length each) were obtained from the trees of each age. Only the effect of age was analyzed for the chemical characterization of the wood. The dimensions of the fibers increased along the pith-bark direction, while wall thickness decreased and the length of the fibers increased with aging. The width of the fibers and the lume diameter increased in the base-top direction. Paricá wood presented low extractive and hemicellulose content, and high cellulose content. The anatomical characteristics were more affected by the factors under study than the chemical composition, evidencing that the chemical elements of the wood are more stable with aging in relation to the anatomical characteristics.

scholarly journals Mineralogy and Geochemistry of the Kinnikinic Quartzite at the Arco Hills Silica and Gold Project in Butte County, Idaho: Results of an Ore Quality Spot Check and Implications for Potential Plasma Furnace Processing

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 523
Author(s):  
Carter Lindeman ◽  
Traister Oglesbee ◽  
Claire McLeod ◽  
Mark P.S. Krekeler
Keyword(s):  
Mineral Exploration ◽  
Economic Value ◽  
Chemical Characterization ◽  
Potassium Feldspar ◽  
Furnace Operation ◽  
Green Economy ◽  
Chemical Components ◽  
Plasma Furnace ◽  
Spot Check

Plasma furnace processing has the potential to transform solar cell production. If informed decisions regarding silicon ore and mineral exploration can be made such that waste streams are also of high economic value, then production is ultimately more environmentally integrated. This study presents results from a spot check of the Kinnikinic Quartzite, ~4.5 km east of Arco, Butte County, Idaho (43.639091°, −113.243295°), for ore quality. The mineralogical and geochemical characteristics are explored within the context of a planned plasma furnace project at the sampled site and are compared to previous consulting reports. X-ray diffraction analysis detected only quartz, while scanning electron microscopy identified quartz grains, secondary quartz cement, trace amounts of potassium feldspar, minor iron oxides, and secondary illite. The bulk chemical characterization of 20 samples (including repeats) reports several wt. % variation in SiO2 from 96.47 to 99.66. Other notable chemical components include Al2O3, K2O, CaO, and Rb, all consistent with the presence of potassium feldspar (and illite). Gold concentrations vary from below detection (n = 12 out of 20) to a maximum concentration of 0.086 ppm. Total sum REE concentrations vary from 13 to 143 ppm. Conservatively and optimistically, assuming ideal extraction and recovery in plasma furnace operation, a resulting waste stream would have approximately 15.2 ppm (0.488 oz./metric ton) gold and 3400 ppm REE in the average waste. Gold (and REE extraction) may, however, be complicated by the presence of Fe and Cu if cyanide approaches were implemented. Gold concentrations are significantly lower than reported in previous work, warranting further characterization of this unit locally and regionally in order to characterize ore potential. This study works to demonstrate the possibility of evaluating other potential silicon ore units, such as the St. Peter Sandstone in Illinois and Missouri, for the co-production of materials in support of an emerging green economy.

scholarly journals Chemical Characterization of Metabolites from the Husk of Theobroma cacao by GC-MS in Cuba

2018 ◽  
Vol 6 (2) ◽  
pp. 39
Author(s):  
Danae Perez ◽  
José González ◽  
Enrique Gómez ◽  
Julio Perez ◽  
José L. Rodríguez ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Phenolic Compounds ◽  
Theobroma Cacao ◽  
Chemical Characterization ◽  
Ethanolic Extract ◽  
Gas Chromatography Mass Spectrometry ◽  
Chemical Components ◽  
Phytochemical Screening

n ethanolic extract at 90% made by Soxhlet was analyzed using a Shimadzu spectrometer coupled to gas chromatography (GCMS-QP2010 Ultra) after derivatization with BSTFA from the husk of Theobroma cacao. The drug powdered was evaluated through a phytochemical screening to get information about the chemical components present in the sample. Ethereal, ethanolic and aqueous extract were analyzed by the same GCMS technique. Gas Chromatography Mass Spectrometry (GC-MS) analysis revealed the presence of 74 metabolites from this husk. According to NIST21 and NIST107 Libraries Databases some of the phyto-compounds screened were Caffeine, Theobromine, Catechine, Uridine, Stigmasterol, Cholesterol and Androstane-11,17-dione,3-[(trimethylsilyl)oxy]-,17-[O-(phenyl methyl)oxime]. Phytochemical screening revealed the possible presence of fats, alkaloids, triterpenes and steroids, catechins, reductants sugars, saponins, phenolic compounds, aminoacids or amines, quinones, anthocyanidins, flavonoids and bitter or astringent principles.

Olfactory and Chemical Characterization of Indoor Air-Towards a Psychophysical Model for Air Quality

1981 ◽  
Author(s):  
Birgitta Berglund ◽  
Ulf Berglund ◽  
Thomas Lindvall ◽  
Helene Nicander-Bredberg
Keyword(s):  
Air Quality ◽  
Indoor Air ◽  
Chemical Characterization

CHARACTERIZATION OF A HYDROGEN PEROXIDE-BENZENE COMPLEX USING MATRIX ISOLATION INFRARED SPECTROSCOPY

2019 ◽  
Author(s):  
Jay Amicangelo ◽  
Lia Totleben ◽  
Jacob Oslosky ◽  
Yudhishtara Payagala ◽  
Catherine Kaiser ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Infrared Spectroscopy ◽  
Matrix Isolation

PURIFICATION AND PARTIAL CHEMICAL CHARACTERIZATION OF SHEEP NEUROPHYSIN

1973 ◽  
Vol 74 (2) ◽  
pp. 226-236 ◽  
Author(s):  
Michel Chrétien ◽  
Claude Gilardeau
Keyword(s):  
Amino Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Chemical Characterization ◽  
Terminal Amino Acid ◽  
Amino Acid Determination ◽  
Pituitary Glands ◽  
Terminal Amino ◽  
Partial Chemical ◽  
Acid Determination

ABSTRACT A protein isolated from ovine pituitary glands has been purified, and its homogeneity assessed by NH2- and COOH-terminal amino acid determination, ultracentrifugation studies, and polyacrylamide gel electrophoresis after carboxymethylation. Its chemical and immunochemical properties are closely similar to those of beef and pork neurophysins, less similar to those of human neurophysins. It contains no tryptophan (like other neurophysins) or histidine (like all except bovine neurophysin-I and human neurophysins). It has alanine at the NH2-terminus and valine at the COOH-terminus. Its amino acid composition is similar to, but not identical with those of porcine and bovine neurophysins.

Sign in / Sign up

Export Citation Format

Share Document