Solubilization of iron and calcium phosphates by soil fungi isolated from coffee plantations

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

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Diversité floristique spontanée des plantations de café et de cacao dans la forêt classée de Monogaga, Côte d'Ivoire | Spontaneous floristic diversity of cocoa and coffee plantations in the classified forest of Monogaga, Côte d'Ivoire (reviewed paper)

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2006.0031 ◽

2006 ◽

Vol 157 (2) ◽

pp. 31-36 ◽

Cited By ~ 2

Author(s):

Constant Yves Adou Yao ◽

Edouard Kouakou N'Guessan

Keyword(s):

Cote D'ivoire ◽

Côte D’Ivoire ◽

Diversity Index ◽

Agricultural Practices ◽

Woody Species ◽

Secondary Forests ◽

Cote D’Ivoire ◽

Coffee Plantations ◽

Côte D'ivoire ◽

High Tree Density

The inventory and the analysis of the woody species preserved in the different categories of cocoa and coffee plantations showed that they are relatively diversified (presence of endemic, rare and threatened species). They also preserved high tree density and high basal areas. The young plantations are especially diversified. Their number of species,density and basal areas and diversity index are similar to those of the neighbouring old growth and secondary forests. Older plantations display a sharp decline of diversity over time. Agricultural practices in the region represent a threat in the medium term to the preservation of biodiversity.

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A differentiated approach to the dental caries prevention in children with different levels of caries risk

Стоматология детского возраста и профилактика ◽

10.33925/1683-3031-2020-20-3-211-215 ◽

2020 ◽

Vol 20 (3) ◽

pp. 211-215

Author(s):

T. N. Tserakhava ◽

N. V. Shakavets ◽

E. I. Melnikava ◽

M. I. Klenovskaya ◽

D. N. Naumovich ◽

...

Keyword(s):

Oral Hygiene ◽

Calcium Phosphates ◽

Clinical Effectiveness ◽

Control Group ◽

Caries Risk ◽

Health Group ◽

High Caries Risk ◽

Permanent Molars ◽

Different Levels ◽

First Permanent Molars

Relevance. Prevention of caries of the first permanent molars is one of the most relevant problems in pediatricdentistry.Purpose – to develop an algorithm for prevention of first permanent molars caries in children with differentlevels of caries risk.Materials and methods. The article presents the results of the implementation of the algorithm for prevention of first permanent molars caries in children with different levels of caries risk. This algorithm includes a comprehensive assessment of the values of indices dmft, DMFT, OHI-S, and the patient's health group is also taken into account. The study involved 253 children aged 6-7 years divided into 4 groups: 3 groups of children depending on the health group and the control group. 3 subgroups were identified in each group – with a low, medium, and high caries risk. We developed preventive measures schemes were for children of each group including training in oral hygiene; controlled and home toothbrushing using fluoride-containing toothpastes; applications of varnishes containing fluoride, calcium, phosphates from 2 to 3 times a year; fissure sealing of the first permanent molars. We carried out these activities were for 24 months, and then evaluated theirs effectiveness. Children in the control group were trained in oral hygiene. The clinical effectiveness of medical prophylaxis was evaluated by changes in the above clinical indicators.Results. In group of children with medium caries risk the increase in caries was 0.09, and the reduction in caries was 89.65%. In children with a low and high caries risk no increase in caries was observed; the reduction in the intensity of caries was 100%. A significant decrease in OHI-S oral hygiene index values was noted in all groups (p < 0.05). We noted high preventive efficacy of fissures sealing in the first permanent molars. No occlusal surface caries developed in sealed fissures.Conclusions. The application of the proposed preventive schemes in patients demonstrates high efficacy of fluoride and calcium-containing varnishes and sealing the fissures of the first permanent molars.

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