scholarly journals THE CHEMICAL COMPOSITION OF THE SURFACE LAYER OF ENAMEL DEPENDING ON ITS FUNCTIONAL STATE

2018 ◽  
pp. 66-71
Author(s):  
N. N. Pustovoitova ◽  
V. V. Kitel
Keyword(s):  
Surface Layer ◽  
Czech Republic ◽  
Great Britain ◽  
Chemical Composition ◽  
High Resolution ◽  
Dental Caries ◽  
Light Elements ◽  
Spectral Analyzer ◽  
Carious Lesions ◽  
Calcium Phosphorus

Objective: to study the chemical composition of the surface layer of enamel in dental caries depending on the activity of carious lesions. Material and methods. The chemical composition of the surface layer of enamel in teeth samples with arrested (n = 15) and active (n = 15) caries was studied using the high resolution SEM «Mira» by the firm «Tescan» (Czech Republic) with the micro spectral analyzer «INCA Energy 350» of the firm «Oxford Instruments Analytical» (Great Britain). Results. We have revealed reliable increases in carbon, oxygen and other light elements in the surface layer of the enamel at the area of active carious lesions in comparison with intact enamel and arrested carious lesions; significant decreases in the content of calcium, phosphorus, ratio of Ca / P coefficient for the surface layer of the enamel of active carious lesions in comparison with intact enamel and arrested carious lesions. We have revealed no reliable differences in the content of C, O, Ca, P, CI in the surface layer of intact enamel and that at the area of arrested no cavity caries.

The role of AGB stars in the evolution of globular clusters

2018 ◽  
Vol 14 (S343) ◽  
pp. 291-300
Author(s):  
Paolo Ventura ◽  
Franca D’Antona ◽  
Marcella Di Criscienzo ◽  
Flavia Dell’Agli ◽  
Marco Tailo
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Globular Clusters ◽  
State Of The Art ◽  
High Resolution Spectroscopy ◽  
Agb Stars ◽  
Light Elements ◽  
Original Population ◽  
Traditional Paradigm

AbstractThe results from high-resolution spectroscopy and accurate photometry have challenged the traditional paradigm that stars in globular clusters (GC) are simple stellar populations, rather suggesting that these structures harbor distinct groups of stars, differing in the chemical composition, particularly in the abundances of the light elements, from helium to silicon. Because this behavior is not shared by field stars, it is generally believed that some self-enrichment mechanism must have acted in GC, such that new stellar generations formed from the ashes of stars belonging to the original population. In this review, after presenting the state-of-the-art of the observations of GC stars, we discuss the possibility that the pollution of the intra-cluster medium was provided by the winds of AGB stars of initial mass above ∼3 M⊙. These objects evolve with time scales of 40 − 100 Myr and contaminate their surroundings with gas processed by p-capture nucleosynthesis, in agreement with the chemical patterns traced by GC stars.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

scholarly journals sCD14 Level in Saliva of Children and Adolescents with and without Dental Caries, a Hurdle Model

Children ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 679
Author(s):  
Gaia Pellegrini ◽  
Marcello Maddalone ◽  
Matteo Malvezzi ◽  
Marilisa Toma ◽  
Massimo Del Fabbro ◽  
...  
Keyword(s):  
Dental Caries ◽  
Innate Immune ◽  
Hurdle Model ◽  
Soluble Cd14 ◽  
Clear Cut ◽  
Carious Lesions ◽  
Decayed Tooth ◽  
Group A ◽  
The Relationship ◽  
Control Study

Objective: Soluble CD14 (sCD14) plays an important role in the innate immune response of the oral cavity. The investigation of this biomarker for detection of carious lesions is an even more actual procedure due to its non-invasiveness and the ease of withdrawal. The purpose of the present observational case-control study was to evaluate whether the quantification of sCD14 in children and adolescent’s saliva can discriminate healthy subjects from those suffering from tooth decay. Materials and Methods: 164 subjects (6 to 17 years) were selected and divided into 2 groups: those with at least 1 decayed tooth were assigned to group Decayed (n = 82) and those free from dental caries to group Healthy (n = 82). The amount of salivary soluble CD14 was quantified. Results: Mean salivary soluble CD14 was 28.3 ± 10.8 μg/mL in the Healthy group and 22 ± 9.6 μg/mL in the Decayed group. A hurdle model was applied to the data to estimate both the probability of having carious lesions and their number in relation to sCD14 levels. sCD14 was strongly associated (p < 0.01) with an inverse relation to both the probability of having caries and their number (falling rate of 5% per unit CD14 μg/mL). Conclusions: This data confirms the relationship between sCD14 and the presence of dental caries. However, there is no clear cut off level between healthy and unhealthy subjects, so it is currently not possible to use sCD14 as a biomarker to determine the risk of decays.

scholarly journals The Voyage of Metals in the Universe from Cosmological to Planetary Scales: the need for a Very High-Resolution, High Throughput Soft X-ray Spectrometer

2021 ◽  
Author(s):  
F. Nicastro ◽  
J. Kaastra ◽  
C. Argiroffi ◽  
E. Behar ◽  
S. Bianchi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Deep Understanding ◽  
High Resolution Spectroscopy ◽  
X Ray ◽  
Viable Solution ◽  
Surrounding Space ◽  
Nuclear Processes ◽  
The Universe ◽  
Very High

AbstractMetals form an essential part of the Universe at all scales. Without metals we would not exist, and the Universe would look completely different. Metals are primarily produced via nuclear processes in stars, and spread out through winds or explosions, which pollute the surrounding space. The wanderings of metals in-and-out of astronomical objects are crucial in determining their own evolution and thus that of the Universe as a whole. Detecting metals and assessing their relative and absolute abundances and energetics can thus be used to trace the evolution of these cosmic components. The scope of this paper is to highlight the most important open astrophysical problems that will be central in the next decades and for which a deep understanding of the Universe’s wandering metals, their physical and kinematical states, and their chemical composition represents the only viable solution. The majority of these studies can only be efficiently performed through High Resolution Spectroscopy in the soft X-ray band.

HIGH-RESOLUTION PIXE USING BRAGG’S SPECTROMETER

1991 ◽  
Vol 01 (03) ◽  
pp. 251-258 ◽  
Author(s):  
M. TERASAWA
Keyword(s):  
High Resolution ◽  
Heavy Ions ◽  
X Rays ◽  
Light Elements ◽  
Element Analysis ◽  
X Ray ◽  
Peak Intensity ◽  
Moderate Energy ◽  
Practical Analysis ◽  
Wavelength Selectivity

K, L, and M X-rays in the wavelengths between 6Å and 130Å generated by the bombardment of 200 keV protons and other heavy ions were measured by means of a wavelength dispersive Bragg’s spectrometer. The X-ray peak intensity was fairly high in general, while the background was very low. The technique was favorably applied to a practical analysis of several light elements (Be, B, C, N, O, and F). Use of moderate-energy heavy ions considering the wavelength selectivity in X-ray generation was effective for the element analysis. The high-resolution spectrometry in the analytical application of ion-induced X-ray generation was found to be useful for the study of fine electronic structure, e.g. satellite and hypersatellite X-ray study, and of the chemical state of materials.

Mycosphaerella oxyacanthae. [Descriptions of Fungi and Bacteria].

2008 ◽  
Author(s):  
T. V. Andrianova
Keyword(s):  
Czech Republic ◽  
Great Britain ◽  
North America ◽  
Geographical Distribution ◽  
Conservation Status ◽  
Voronezh Oblast ◽  
Saratov Oblast ◽  
Crataegus Laevigata ◽  
Kursk Oblast ◽  
Astrakhan Oblast

Abstract A description is provided for Mycosphaerella oxyacanthae, which sometimes causes lesions on leaves of Crataegus laevigata. Some information on its dispersal and transmission and conservation status is given, along with details of its geographical distribution (North America (USA), Asia (Armenia, Azerbaijan, China, Georgia, India, Iran, Kazakhstan, Kirgizstan [Kyrgyzstan], Russia, Turkey, Turkmenistan, Uzbekistan), Europe (Austria, Belgium, Bulgaria, Czech Republic, Denmark, France, Germany, Great Britain, Hungary, Italy, Latvia, Norway, Portugal, Romania, Russia (Astrakhan oblast, Kursk oblast, Saratov oblast, Stavropolskyi krai, Voronezh oblast), Sweden, Switzerland and Ukraine)) and hosts (Phoma macrostoma, Crataegus ambigua, C. beckeriana, C. chlorocarpa, C. curvisepala [syn. C. kyrtostyla], C. laevigata [syn. C. oxyacantha], C. macracantha, C. microphylla, C. mollis, C. monogyna, C. pinnatifida, C. remotilobata, C. sanguinea, C. songarica [C. songorica], C. volgensis, and Crataegus sp.).

Septoria antirrhini. [Descriptions of Fungi and Bacteria].

2004 ◽  
Author(s):  
T. V. Andrianova
Keyword(s):  
South Africa ◽  
Czech Republic ◽  
New Zealand ◽  
Great Britain ◽  
South America ◽  
Geographical Distribution ◽  
Infected Plant ◽  
Weather Conditions ◽  
Plant Debris ◽  
Wet Weather

Abstract A description is provided for Septoria antirrhini. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Leaf spot, leaf drying, defoliation. HOSTS: Antirrhinum antirrhiniflorum, A. majus, A. siculum (Scrophulariaceae). GEOGRAPHICAL DISTRIBUTION: AFRICA: South Africa. NORTH AMERICA: Canada, USA. SOUTH AMERICA: Chile, Colombia. ASIA: Armenia, Azerbaijan, China, Iran, Israel. AUSTRALASIA: Australia, New Zealand. EUROPE: Bulgaria, Czech Republic, Estonia, France, Germany, Great Britain, Hungary, Ireland, Italy, Netherlands, Portugal, Romania, Ukraine, former Yugoslavia. TRANSMISSION: Not reported, but almost certainly by airborne, splash-dispersed conidia from infected plant debris and seed stocks. The disease is significantly more severe under wet weather conditions (SINADSKIY et al., 1985).

Mycotypha microspora. [Descriptions of Fungi and Bacteria].

2008 ◽  
Author(s):  
P. M. Kirk
Keyword(s):  
Czech Republic ◽  
Great Britain ◽  
Lycopersicon Esculentum ◽  
Geographical Distribution ◽  
Tamil Nadu ◽  
Pennisetum Glaucum ◽  
Homo Sapiens ◽  
District Of Columbia ◽  
Citrus Aurantium ◽  
Decaying Wood

Abstract A description is provided for Mycotypha microspora. Details of its geographical distribution (Libya, Nigeria, India (Tamil Nadu), Thailand, USA (Arizona, California, District of Columbia, Iowa, Kansas, Massachusetts), Czech Republic, Finland, France, Germany, Great Britain, Netherlands, Poland, Turkey), and associated organisms and substrata (Equus caballus (dung), Homo sapiens, Muridae (dung), Carnegiea gigantea, Citrus aurantium, Gossypium, Lycopersicon esculentum, Pennisetum typhoideum [Pennisetum glaucum], air, bark, decaying wood, dung, leaf, paper and rhizosphere) are provided.

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