scholarly journals FEATURES OF DENTINE CHEMICAL COMPOSITION OF INTACT TEETH AND TEETH WITH WEDGE-SHAPED DEFECTS

2021 ◽  
Vol 74 (8) ◽  
pp. 1869-1875
Author(s):  
Svitlana P. Yarova ◽  
Iryna I. Zabolotna ◽  
Olena S. Genzytska ◽  
Andrii A. Komlev
Keyword(s):  
Chemical Composition ◽  
Chemical Elements ◽  
Cervical Region ◽  
Cervical Lesions ◽  
X Ray ◽  
Sodium Magnesium ◽  
Calcium Phosphorus ◽  
Cervical Area ◽  
Focused Beam

The aim: Is to define dentine chemical composition of intact teeth and those with wedge-shaped defects followed by the analysis of revealed differences. Materials and methods: Longitudinal sections of 22 clinically removed teeth (12 – clinically intact ones, 10 – with wedge-shaped defects) from both jaws were studied in patients aged between 25-54 years. JSM-6490 LV focused beam electron microscope (scanning) with system of energy-dispersive X-ray microanalysis INCA Penta FETх3 was used. The chemical composition of 148 dentine areas in the incisal region (tubercle), equator, cervical area has been determined as a percentage of the weight amounts of carbon, oxygen, calcium, phosphorus, sodium, magnesium, sulfur, chlorine, zinc, potassium, aluminum. Results: Dentine chemical composition of teeth with wedge-shaped defects differed from those of intact teeth by significantly lower content: sodium, chlorine and calcium – in the incisal region (tubercle); sodium, magnesium − at the equator; sodium, chlorine and calcium – in the cervical region (p≤0.05). In the sample groups with cervical pathology there was more sulfur and oxygen in the incisal region (tubercle), phosphorus and zinc – at the equator, carbon and potassium – in the cervical region (p≤0.05). Conclusions: Differences in the chemical composition of intact teeth and teeth with wedge-shaped defects, the presence of correlation between the studied chemical elements confirm the role of macro- and microelements in the pathogenesis of non-carious cervical lesions.

scholarly journals The role of heat conduction to the formation of [WC]-type planetary nebulae

2011 ◽  
Vol 7 (S283) ◽  
pp. 494-495
Author(s):  
Christer Sandin ◽  
Matthias Steffen ◽  
Ralf Jacob ◽  
Detlef Schönberner ◽  
Ute Rühling ◽  
...  
Keyword(s):  
Heat Conduction ◽  
Chemical Composition ◽  
Physical Properties ◽  
Planetary Nebulae ◽  
Time Dependent ◽  
Diffuse Emission ◽  
Hydrodynamic Models ◽  
X Ray ◽  
Central Stars

AbstractX-ray observations of young Planetary Nebulæ (PNe) have revealed diffuse emission in extended regions around both H-rich and H-deficient central stars. In order to also reproduce physical properties of H-deficient objects, we have, at first, extended our time-dependent radiation-hydrodynamic models with heat conduction for such conditions. Here we present some of the important physical concepts, which determine how and when a hot wind-blown bubble forms. In this study we have had to consider the, largely unknown, evolution of the CSPN, the slow (AGB) wind, the fast hot-CSPN wind, and the chemical composition. The main conclusion of our work is that heat conduction is needed to explain X-ray properties of wind-blown bubbles also in H-deficient objects.

Multi-Component Coatings Formation on Polycathode Magnetron Sputtering Systems

2017 ◽  
Vol 265 ◽  
pp. 166-170
Author(s):  
V.V. Kolesnik ◽  
Yu.K. Rubanov ◽  
Yu.E. Tokach
Keyword(s):  
Chemical Composition ◽  
Magnetron Sputtering ◽  
Coating Thickness ◽  
Diffusion Zone ◽  
Chemical Elements ◽  
Substrate Material ◽  
Coating Materials ◽  
Surface Microrelief ◽  
X Ray ◽  
Coating Formation

The results of experiments aimed at obtaining multi-component coatings, having a wider range of properties compared to single-component coatings, are provided. The process of formation of coating based on multi-component alloy Co (18...20%)-Cr (5...7%)-Al (0.3...0.4%)-Y(0.2...0.5) was studied. The chemical composition and thickness of the coating as well as the state of the transition layer were also studied. The results of electron probing and X-ray fluorescence microanalysis of obtained coatings are provided. This paper also demonstrates that the properties of surface microrelief are determined by the conditions of coating formation; that each sample of coating has similar sets of chemical elements, that their concentration depends on the precipitation conditions, chemical elements are equally distributed along the thickness of samples, and the diffusion zone of coating materials and substrate is almost non-existent. The low content of substrate material was found in obtained coatings. As the coating thickness increased, the content of substrate material decreased sharply.

scholarly journals SOME PROTECTIONS ON THE ROLE OF GEOCHEMICAL PROPERTIES OF CHEMICAL ELEMENTS IN THE PROBLEMS OF ENVIRONMENTAL POLLUTION AND PROTECTION

2021 ◽  
Vol 07 (03) ◽  
pp. 31-34
Author(s):  
Intizar Aliyeva Intizar Aliyeva ◽  
Rasul Hajıyev Rasul Hajıyev
Keyword(s):  
Spectral Analysis ◽  
Negative Impact ◽  
Chemical Elements ◽  
Low Cost ◽  
High Sensitivity ◽  
X Ray ◽  
Geochemical Properties ◽  
Geochemical Parameters ◽  
Industrial Complexes

The article discusses various limited considerations and assumptions on the positive or negative impact of geochemical features chemical elements found in rocks, ores, soil, plants, water and in the air of the territories of populated areas, factories, the mining and agro-industrial complexes to the environment and the role of analytical geochemistry in this process. According to the author, one of the main points on which the light should be shed is the role of finding elements (independent, combination or isomorphic mixture) rather than their existence in different amounts in the environment. Thus, the chemical elements can be more or less hazardous to environment regardless its amount, but the finding methods. Chemical and natural combinations can be either very hazardous or very useful to all living creatures depending on their characteristics, so it’s better to determine their environmental hazardousness via their impact to a particular human or animal organ which in turn facilitates the solution of the problem. Moreover, it should be noted that the most environmentally dangerous and active chemical elements are the ones with fluctuating valence. Some elements are not so hazardous when they are independent or in solid form since they change weakly. But they are very dangerous when they turn into liquid or gas forms and create mineral compounds with other elements such as halkofil group of elements which in turn can easily decompose and dissolve in water by causing dangers to all living creatures in the nature. Approximately any chemical element can either react negatively or in most cases stimulate the life functions of the organs of animals and plants depending on its finding forms. The study of geochemical parameters in different natural objects such as surface and subsoil water, air, rocks and ores can be very helpful in organizing the protection of environmetal and the solution of its problems. X-ray Spectral analysis is particularly highlighted in this article for identifying various chemical elements in geological and ecological objects. There are several advantages of X-ray Spectral analysis such as its productiveness and low cost, the expressiveness and simplicity of analysis operations, having slightly high sensitivity, universality, high range of elements identification features, etc. To conclude some authors claim that the following problems can be solved with the help of analytic geochemistry: Identifying the main source of pollution and the evaluation of its impact on the environment; Identification of quantitative and qualitative parameters of sources of natural, techno and agro genic pollution in the settlements, industrial objects and in the regions of developed mining complexes; Eco-geochemical and biochemical evaluation of the negative impact of water, weather and harmful geochemical anomalies on live organisms. We hope the elimination of this type of problems can pave the way to the ecologically clean environment. Keywords: ore, soil, plant, water, weather.

scholarly journals A Comparative Chemical Study of Calcium Silicate-Containing and Epoxy Resin-Based Root Canal Sealers

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Przemysław Reszka ◽  
Alicja Nowicka ◽  
Mariusz Lipski ◽  
Włodzimierz Dura ◽  
Agnieszka Droździk ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Root Canal ◽  
Calcium Silicate ◽  
Chemical Elements ◽  
Petri Dish ◽  
Chemical Study ◽  
X Ray ◽  
Sodium Magnesium ◽  
Inner Diameter ◽  
Root Canal Sealers

Objective.The present study assessed the chemical elements in two novel calcium silicate-containing root canal sealers, BioRoot RCS and Well-Root ST, compared to a calcium silicate-containing root canal sealer that has been on the market for several years, MTA Fillapex, and epoxy resin-based sealer AHPlus.Material and Methods.The sealers were mixed and manipulated according to the manufacturers’ instructions. Twelve cylindrical molds (inner diameter 4 mm; height 3 mm) were placed on a glass petri dish and packed with the materials. The dish was transferred to an incubator. After 72 h the molds were examined by scanning electron microscopy and energy dispersive X-ray microanalysis.Results.BioRoot RCS and Well-Root ST had high peaks of calcium, zirconium, oxygen, carbon, silicon, and chlorine. Well-Root ST also had sodium, magnesium, aluminum, and titanium peaks. MTA Fillapex and AHPlus had carbon, oxygen, calcium, titanium, and bismuth peaks. A silicon peak was also observed for MTA Fillapex, and zirconium and tungsten peaks for AHPlus.Conclusion.BioRoot RSC had the highest degree of purity. The clinical implication of metals contained in the other sealers needs to be investigated.

scholarly journals Characterisation of copper alloy antique ornamental accessories found in Northern Albania

2014 ◽  
Vol 2 (2) ◽  
Author(s):  
Olta Çakaj ◽  
Edlira Duka ◽  
Zamir Tafilica ◽  
Frederik Stamati ◽  
Nikolla Civici ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Copper Alloy ◽  
Evaluation Method ◽  
Chemical Elements ◽  
Casting Process ◽  
Metallic Alloys ◽  
Corrosion Products ◽  
X Ray ◽  
Lead Alloys ◽  
Polarised Light

This study was performed to determine the chemical elements used to produce ancient metallic alloys and to understand the manufacture technique of three archaeological founds. It also presents an evaluation method of the objects’ authenticity based on the observation of the corrosion products. This article also includes three ornamental accessories ca. VII-IV century BC found in the vicinity of Shkodra (Albania). A necklace, a belt application and a button are examined using X ray fluorescence (XRF) to determine the chemical composition and optical microscopy (OM) with reflected and polarised light in order to study the microstructure and the corrosion products. From the XRF results all the objects are bronze, copper-tin and copper-tin-lead alloys. After the OM analysis they are authentic objects (not fake replicas) and might have been produced after a casting process in moulds.

scholarly journals Analysis of Chemical Composition of Different Irreversible Hydrocolloids

2018 ◽  
Vol 6 (3) ◽  
pp. 37 ◽  
Author(s):  
Antonio Borges de Olival ◽  
Nilton da Penha Junior ◽  
João Câmara ◽  
Ana Corrêa Duarte Simões ◽  
José Estruc Verbicário dos Santos ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Chemical Elements ◽  
Deionized Water ◽  
Dental Practice ◽  
Volumetric Flask ◽  
Cobalt Nickel ◽  
Iron Copper ◽  
Health Damage ◽  
Sodium Magnesium ◽  
Dental Impression

Irreversible hydrocolloids (IR) is a dental impression material commonly used in Brazilian and European dental practice because it is inexpensive, easy to handle, has good reproductive detail and is comfortable for the patient. This research aimed to analyze the chemical composition of eight different IRs for dental use. A sample of 0.2 g was weighed and transferred to a Teflon beaker moistened with drops of distilled or deionized water; 5 mL of nitric acid was added until total solubility of the sample; the solution was transferred to a 100 mL volumetric flask, the volume was filled with distilled or deionized water and homogenized. Thirty-five chemical elements were found: Lithium, Beryllium, Boron, Sodium, Magnesium, Aluminum, Silicon, Phosphorus, Potassium, Titanium, Manganese, Cobalt, Nickel, Vanadium, Zinc, Rubidium, Arsenic, Iron, Copper, Strontium, Yttrium, Zirconium, Niobium, Molybdenum, Ruthenium, Cadmium, Tin, Antimony, Barium, Lanthanum, Cerium, Mercury, Lead, Thorium and Uranium. Only one of the samples contained no Nickel, Antimony and Lead; and Arsenic and Uranium were found in 2 samples. This study provided evidence of high toxicity of the IR brands, pointing out the need for better quality control of this product, in order to prevent health damage in dentists, prosthesis technicians and patients.

scholarly journals Research of the Chemical Composition of Industrial Waste of the Kadamzhay Antimony Combine

2020 ◽  
Vol 6 (12) ◽  
pp. 73-78
Author(s):  
N. Erkinbaeva ◽  
Y. Tashpolotov ◽  
E. Ysmanov
Keyword(s):  
Chemical Composition ◽  
Industrial Waste ◽  
Toxic Elements ◽  
Chemical Elements ◽  
New Products ◽  
Atomic Emission ◽  
Waste Dump ◽  
X Ray ◽  
Fluorescence Methods ◽  
Titanium Vanadium

This article investigates the chemical composition of industrial waste (dump slag and flotation tailings). This study, in contrast to previous studies, was carried out by chemical, atomic emission, X-ray fluorescence methods. Valuable rare earth chemical elements (ytterbium, yttrium, lanthanum, scandium), valuable chemical elements (antimony, titanium, vanadium, tungsten, niobium, indium, germanium, gallium, tantalum, molybdenum, strontium, beryllium, zirconium, cobalt) and others have been determined. The oxides of elements (SiO2, Al2O3, MgO, CaO, Fe2O3, Na2O, K2O, S, FeO) have been investigated. Toxic elements (arsenic, cadmium, tin, lead). These studies were carried out with the aim of using man-made waste in various sectors of the national economy for the disposal of man-made waste and to improve the environmental situation in the region and reduce material costs for the production of new products.

scholarly journals Physicochemical investigation of shrimp fossils from the Romualdo and Ipubi formations (Araripe Basin)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6323 ◽  
Author(s):  
Olga Alcântara Barros ◽  
João Hermínio Silva ◽  
Gilberto Dantas Saraiva ◽  
Bartolomeu Cruz Viana ◽  
Alexandre Rocha Paschoal ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Chemical Elements ◽  
Hydroxyl Group ◽  
Large Field ◽  
Field Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Iron Aluminum ◽  
Physicochemical Investigation ◽  
Dominant Phase

The Ipubi and Romualdo Formations are Cretaceous units of the Araripe Basin (Santana Group). The first and most ancient was deposited in a lake environment, and some fossils were preserved in shales deposited under blackish conditions. The second was deposited in a marine environment, preserving a rich paleontological content in calcareous concretions. Considering that these two environments preserved their fossils under different processes, in this work we investigated the chemical composition of two fossilized specimens, one from each of the studied stratigraphic units, and compared them using vibrational spectroscopy techniques (Raman and IR), X-ray diffraction and large-field energy-dispersive X-ray spectroscopy (EDS) mappings. Calcite was observed as the dominant phase and carbon was observed in the fossils as a byproduct of the decomposition. The preservation of hydroxide calcium phosphate (Ca10(PO4)6(OH)2, hydroxyapatite) was observed in both fossils. In addition, it was observed that there was a smaller amount of pyrite (pyritization) in the Romualdo Formation sample than in the Ipubi one. Large-field EDS measurements showed the major presence of the chemical elements calcium, oxygen, iron, aluminum and fluoride in the Ipubi fossil, indicating a greater influence of inorganic processes in its fossilization. Our results also suggest that the Romualdo Formation fossilization process involved the substitution of the hydroxyl group by fluorine, providing durability to the fossils.

scholarly journals Morphology and Chemical Composition of Silicon Carbide Surface in Interaction with Titanium Alloy under Micro-Scratching Conditions

2020 ◽  
Vol 329 ◽  
pp. 02010
Author(s):  
Vladimir Nosenko ◽  
Aleksandr Fetisov ◽  
Sergey Nosenko ◽  
Valeria Puzyrkova
Keyword(s):  
Silicon Carbide ◽  
Titanium Alloy ◽  
Chemical Composition ◽  
Path Length ◽  
Chemical Elements ◽  
Cooling Process ◽  
Corundum Crystal ◽  
Initial Shape ◽  
X Ray ◽  
Cutting Path

The article describes features of the wear site morphology formation during micro-scratching of a titanium alloy by a silicon carbide crystal in comparison with a corundum crystal. The initial shape of the crystal top and the rate of micro-scratching were assumed to be constant. No lubricating or cooling process media were used. External factors: micro-scratch depth and cutting path length. The chemical composition of wear sites was studied using micro-x-ray spectral analysis. The content of chemical elements in the surface layer of silicon carbide and adhered metal was studied at separate points and by area scanning. The accelerating voltage of the excitation electrons was changed in the range from 5 to 20 kV. The concentration of chemical elements on the surface of the wear site was determined immediately after micro-scratching and after removing the adhered metal by etching. The regularities of changes in the concentration of chemical elements depending on the accelerating voltage of the excitation electrons were determined.

Henry Moseley, X-ray spectroscopy and the periodic table

2020 ◽  
Vol 378 (2180) ◽  
pp. 20190302 ◽  
Author(s):  
Russell G. Egdell ◽  
Elizabeth Bruton
Keyword(s):  
Periodic Table ◽  
Chemical Elements ◽  
Atomic Weight ◽  
X Rays ◽  
Radioactive Elements ◽  
Theme Issue ◽  
X Ray ◽  
Series Of Experiments ◽  
Radiological Characterization

Just over 100 years ago, Henry Moseley carried out a systematic series of experiments which showed that the frequencies of the X-rays emitted from an elemental target under bombardment by cathode rays were characteristic of that element and could be used to identify the charge on its atomic nucleus. This led to a reorganization of the periodic table, with chemical elements now arranged on the basis of atomic number Z rather than atomic weight A, as had been the case in previous tables, including those developed by Mendeleev. Moseley also showed that there were four ‘missing elements’ before gold. With further measurements up to uranium Z = 92, the Swedish physicist Manne Siegbahn identified two more missing elements. This paper provides an introduction to Moseley and his experiments and then traces attempts to ‘discover’ missing elements by X-ray spectroscopy. There were two successes with hafnium (Z = 72) and rhenium (Z = 75), but many blind alleys and episodes of self-deception when dealing with elements 43, 61, 85 and 87. These all turned out to be radioactive, with extremely small natural abundances: all required synthesis by a nuclear reaction, with radiological characterization in the first instance. Finally, the paper moves on to consider the role of X-ray spectroscopy in exploring the periodic table beyond uranium. Although the discovery of artificial radioactive elements with Z > 92 again depended on nucleosynthesis and radiological characterization, measurement of the frequencies or energies of characteristic X-rays remains the ultimate goal in proving the existence of an element. This article is part of the theme issue ‘Mendeleev and the periodic table’.

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