Calculation of magnetic parameters of iron-contained nanoparticles

Some values of magnetic parameters of iron-containing nanoparticles were calculated. The result of the calculations show that starting from 5 nm, the dimensions offen, nanoparticles behave themselves as magnetic materials. Key words: iron-containing nanoparticles, magnetic saturation, magnetic perception, ferromagnetic, superparamagnetic

Radiation protection at the iron mines in the conditions of technogenically increased sources of natural origin

The Purpose of the Research. To draw up a system of measures for radiation protection at the iron ore mines to facilitate the control of the natural exposure component of miners and to ensure that the established dose criteria are not exceeded. Methodsand Materials. During the development of the measures, the results and conclusions of the radiation-hygienic study of the Kryvyi Rih Agglomeration iron ore mines, the territory of which was identified as radon-dangerous with the presence of man-made sources of natural origin, were used. The measurements were made on the selected network of control points at the horizons of the mines. For analysis, the system was used to measure the volumetric activity of radon and its subsidiary decay products in the mine atmosphere, the dose rate of gamma radiation in mines, the content of natural radionuclides in the ores, the dustiness of the mine atmosphere. At the same time, they were guided by the main regulatory and methodological base. Results and Conclusions.The main stages of the developed system of radiation protection at iron ore mines in terms of technogenic-enhanced sources of natural origin are: radiation-hygienic examination, radiation control, protection measures for normalization of radiation situation, control of the effectiveness of radiation prevention, preventive protection. The decision on the need for radiation monitoring and the implementation of radiation protection measures for iron ore mines is made on the basis of the preliminary survey, which determines the categories of the mine and the type of control. On the basis of the conducted research of iron ore mines of Kryvyi Rih Agglomeration, a system of radiation protection was developed and ordered, the sequence of implementation of measures of radiation examination, radiation control and normalization of radiation situation was substantiated. The measures developed need to be consistent with the recommendations of the International Commission on Radiation Protection regarding radiological protection against radon exposure in the workplace. Key Words: iron ore mines, radiation protection, radiation control, radon, man-made sources of natural origin, miners.

Iron metabolism and chronic kidney disease

Iron is involved in all kinds of metabolism. Iron deficiency, even in the absence of anaemia, promotes the development of many diseases. But in inflammation-associated diseases iron accumulates in the liver, kidneys and macrophages; resulting in impairment of effective erythropoiesis. The review presents modern evidence of the molecular mechanisms of iron metabolism and metabolic changes in most common diseases of the organs of the urinary system – pyelonephritis, glomerulonephritis, acute kidney injury. In most cases, anaemia has a dual nature – true iron deficiency anaemia and anaemia of chronic disease. Key words: iron, erythropoiesis, anaemia, renal pathology

Use of an in vitro method to determine the effects of chelators on potential iron bioavailability in diets for ruminants

An in vitro method was developed to evaluate the effect of adding chelators on the potential bioavailability of iron in diets for veal calves. The control diet was composed of corn grain and a protein supplement. The experimental diets comprised the control diet plus lignin, Na2-EDTA or Ca2-EDTA as chelators. Total soluble iron of diets containing chelators was lower than that of the control diet (P < 0.05), and both types of EDTA reduced soluble iron more than lignin (P < 0.01). Key words: Iron, solubility, in vitro, chelator, ruminant

The effect of sample grinding on extractable iron and aluminum in soils

Pyrophosphate-, dithionite- and acid ammonium oxalate-extractable Fe and Al are often measured on a finely ground aliquot of soil. Grinding provides a homogeneous sample from which a representative subsample can be obtained at sampling aliquots of less than 1 g. When a significant portion of the unground soil is greater than the sieve mesh size used when grinding, abrasion of primary minerals may cause increased levels of extractable Fe and Al. This study examined the distribution of extractable Fe and Al in some sandy soils and compared their levels in samples ground to < 500 μm and < 150 μm with those in unground < 2-mm soil. Samples ground to < 150 μm yielded the highest amounts of extractable Fe and Al. This effect was most prevalent when a motorized mortar and pestle was used. Samples ground to < 500 μm, which were frequently re-sieved to avoid over-grinding, contained similar amounts of extractable Fe and Al as the unground < 2-mm sample. If less than 1 g of soil is used for analysis, a sample manually ground to < 500 μm (35 mesh) is advisable and a protocol for sample grinding is recommended. Key words: Iron, aluminum, pyrophosphate, dithionite, oxalate, grinding

Receptors for transferrin in pathogenic bacteria are specific for the host's protein

Transferrin receptors detected by a solid-phase binding assay were shown to be specific for the host's transferrin in the representative bacterial pathogens Neisseria meningitidis (human), Pasteurella haemolytica (bovine), and Actinobacillus pleuropneumoniae (porcine). Consistent with the receptor specificity, iron-deficient bacteria were only capable of utilizing transferrin from the host as a source of iron for growth. Key words: iron, transferrin, receptor.

EFFECT OF IRON ON THE NATURE OF PRECIPITATION PRODUCTS OF ALUMINUM

Solutions Of AlCl3 (5 × 10−3 mol L−1) and FeCl2 were mixed and aged for 3 yr under ambient conditions at the initial pH of 7.0 and Fe:Al molar ratios of 0, 0.1, 0.3, 0.5 and ∞ (Fe at 5 × 10−3 mol L−1). Fe2+ was readily oxidized in this experiment so that only the mutual interaction between Fe3+ and Al3+ can be reported. The initial Fe:Al molar ratio was an important parameter in determining the rate and amount of hydrolysis and precipitation of Fe and Al. At Fe:Al molar ratios ≤ 0.3, hydrolysis was delayed when compared to that in pure Al suspensions. At higher ratios more acidity was produced by hydrolytic reactions. The acidity was contributed by both Al and Fe. The fractions of Fe and Al precipitated were greater at lower Fe:Al molar ratios. Aluminum and iron were mutually interfering cations during crystallization. In mixed systems, the fractions of crystalline materials were greatly reduced. Between the crystalline compounds, gibbsite was more abundant than bayerite and this evolution was governed by pH and the interference of Fe on the subsequent rate of hydrolysis and crystallization. Iron substitution was not evident in the crystalline Al(OH)3 polymorphs. Crystalline Fe oxides could not be detected even at the Fe: Al molar ratio of 0.1. Two discrete oxide phases were formed in the mixed Fe-Al systems consisting of crystalline Al(OH)3 and a mixed Fe-Al oxide of indeterminate composition. In the pure ferric suspension, maghemite was formed. The results presented are used to explain the distribution of aluminum hydroxide polymorphs in soil and the genesis of gibbsite and iron oxide containing horizons of Oxisols. Key words: Iron, aluminum, gibbsite, bayerite, maghemite, Fe-Al surface coatings