Faculty of Natural Sciences and Mathematics

Permanent URI for this communityhttps://repository.ukim.mk/handle/20.500.12188/16

Browse

Search Results

Now showing 1 - 10 of 48

Some of the metrics are blocked by your
consent settings
Pharmacokinetics of different selenium supplements in healthy individuals and patients with autoimmune thyroiditis after oral administration
(Society of Chemists and Technologists of Macedonia, 2025-06-24)
;
;
;
Stafilov, Trajče
Selenium is essential for the function of key selenoproteins such as glutathione peroxidase, thiore-doxin reductase, and iodothyronine deiodinase, which have antioxidant properties and support thyroid hormone metabolism. Due to the low selenium content in European soils – particularly in the Southeast-ern regions, supplementation is often recommended, especially for conditions like Hashimoto's thyroidi-tis. However, careful consideration of selenium dosage and pharmacokinetics is crucial, as the margin be-tween essential and toxic levels is very narrow. The aim of this study was to investigate the pharmacoki-netics of selenium absorption and plasma concentration following oral administration of various selenium doses and chemical forms, both in the short and long term, in healthy individuals and patients with auto-immune thyroiditis. Selenium concentrations in blood plasma were measured using electrothermal atomic absorption spectrometry (ETAAS). The study found that L-selenomethionine is absorbed more efficiently than inorganic sodium selenite, with peak plasma concentrations reached and sustained within 6 – 8 hours. Selenium levels remained elevated 48 hours after ingestion compared to baseline. At a daily dose of 200 μg of selenium as L-selenomethionine, plasma selenium concentrations increased by approximate-ly 30 %, and by about 25 % at 100 μg/day, relative to the initial value. Long-term studies showed that plasma selenium concentrations rose significantly after the first month of supplementation, with a slower increase in subsequent months. After supplementation ended, selenium levels declined rapidly. Interest-ingly, no significant differences in selenium absorption or excretion were observed between patients with Hashimoto's thyroiditis and healthy controls.
Some of the metrics are blocked by your
consent settings
Evaluation of immunoconjugates of non-radioactive lutetium- and yttrium-rituximab – a vibrational spectroscopy study
(Society of Chemists and Technologists of Macedonia, 2015-11-12)
Gjorgieva Ackova, Darinka
;
Smilkov, Katarina
;
Janevik-Ivanovska, Emilija
;
Stafilov, Trajče
;
Arsova-Sarafinovska, Zorica
<jats:p><p>Fourier Transform Infrared (FT-IR) and Raman spectroscopy were used to study the molecular structure of the recombinant monoclonal antibody and anti-CD20-conjugates which are intended to be used as anti-cancer therapeutic agents. We characterized the secondary structure of a therapeutic immunoconjugates, formulated with different bifunctional chelating agents and labeled with non-radioactive lutetium and yttrium. The secondary structure content of all three immunoconjugates was assessed to be similar to that of unlabeled antibody. In addition, no significant changes upon lyophilizing procedures were observed. The results demonstrate that amide bands could be taken as analytical peak which enables quick and reliable way for screening of protein pharmaceuticals during development of lyophilized formulations.<strong></strong></p></jats:p>
Some of the metrics are blocked by your
consent settings
Multivariate extraction of dominant geochemical markers for deposition of 69 elements in the Bregalnica River basin, Republic of Macedonia (moss biomonitoring)
(2016-11)
Balabanova, Biljana
;
Stafilov, Trajče
;
Šajn, Robert
;
Tănăselia, Claudiu
Atmospheric deposition was investigated using the terrestrial moss species Hypnum cupressiforme (Hedw.) and Homolothecium lutescens (Hedw.) in the Bregalnica River basin, Republic of Macedonia. Long-term emission occurs in this area due to the hydrothermal exploitation of Pb-Zn deposits (Sasa and Zletovo mines) and copper ore exploitation and floatation (Bučim mine). Determination of the chemical elements was conducted using atomic emission spectrometry with inductively coupled plasma (ICP-AES) and mass spectrometry with inductively coupled plasma (ICP-MS). A combination of multivariate techniques (PCA, FA and CA) was applied for data processing and identification of element association with lithogenic/anthropogenic origin. Seven dominant factors were extracted from the total of 69 analysed elements. Spatial distribution maps were constructed for the determination and localisation of smaller areas with higher contents of certain anthropogenic elements. In this way, the influences of selected human activities on local air pollution can be determined. The summarised data show quantification of the element distributions. This not only allows the determination of the distribution of hazardous elements but also presents complete characterisation of element deposition in the environs of mines.
Some of the metrics are blocked by your
consent settings
Distribution of chemical elementsin soil samples from the Pelagoniaregion, Republic of Macedonia
(Croatian Geological Survey, 2015-11-01)
Puteska, Ana
;
Dimovska, Bojana
;
Šajn, Robert
;
Stafilov, Trajče
Some of the metrics are blocked by your
consent settings
Determination of iron in drinking water after its flotation concentration by two new dithiocarbamate collectors
(2015)
Pavlovska, Gorica
;
Stafilov, Trajče
;
Čundeva, Katarina
Two new methods for the determination of iron by atomic absorption spectrometry (AAS) are proposed for drinking water. The determination was made after flotation concentration of Fe by using of two new flotation collectors: lead(II) heptyldithiocarbamate, Pb(HpDTC)2 and cobalt(III) heptyldithiocarbamate Co(HpDTC)3. All important parameters for the two proposed procedures were optimised (pH, mass of Pb, mass of Co, amount of HpDTC(-), type of surfactant, induction time, etc.). Flotation recovery (R) of Fe was very high (from 94.4 to 104.4%) for the two proposed procedures. The detection limit of the methods was 2.17 μg L(-1) for Pb(HpDTC)2 and 2.39 μg L(-1) for Co(HpDTC)3, respectively. The proposed methods have been applied for the analysis of five samples of drinking water. The acquired AAS results for Fe by both new methods were compared with those obtained by inductively coupled plasma-atomic emission spectrometry (AES-ICP). It is shown that they are in good agreement. The results are also confirmed by the method of standard additions.
Some of the metrics are blocked by your
consent settings
Phenolic compounds and antioxidant activity of Macedonian red wines
(Elsevier BV, 2015-08)
Ivanova-Petropulos, Violeta
;
Hermosín-Gutiérrez, Isidro
;
Boros, Borbála
;
;
Stafilov, Trajče
Some of the metrics are blocked by your
consent settings
Multi-element atmospheric deposition in Macedonia studied by the moss biomonitoring technique
(Springer Science and Business Media LLC, 2015-10)
;
Frontasyeva, Marina V
;
Stafilov, Trajče
;
Šajn, Robert
;
Ostrovnaya, Tatyana M
Moss biomonitoring technique using moss species Homolothecium lutescens (Hedw.) Robins and Hypnum cupressiforme (Hedw.) was applied to air pollution studies in the Republic of Macedonia. The study was performed in the framework of the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops under the auspices of the United Nations Economic Commission for Europe (UNECE) Convention on Long-Range Transboundary Air Pollution (LRTAP). The presence of 47 elements was determined by instrumental epithermal neutron activation analysis, atomic absorption spectrometry and atomic emission spectrometry with inductively coupled plasma. Normality of the datasets of elements was investigated, and Box-Cox transformation was used in order to achieve normal distributions of the data. Different pollution sources were identified and characterized using principal component analysis (PCA). Distribution maps were prepared to point out the regions most affected by pollution and to relate this to the known sources of contamination. The cities of Veles, Skopje, Tetovo, Radoviš and Kavadarci were determined to experience particular environmental stress. Moreover, three reactivated lead-zinc mines were also shown to contribute to a high content of lead and zinc in the eastern part of the country. However, a comparison with the previous moss survey conducted in 2005 showed a decreasing trend of pollution elements that are usually associated with emission from industrial activities.
Some of the metrics are blocked by your
consent settings
Bioavailability and bioaccumulation characterization of essential and heavy metals contents in R. acetosa, S. oleracea and U. dioica from copper polluted and referent areas
(Springer Science and Business Media LLC, 2015)
Balabanova, Biljana
;
Stafilov, Trajče
;
Bačeva, Katerina
Bioavailability of metals occurring in soil is the basic source of its accumulation in vegetables and herbs. The impact of soil pollution (due to urban and mining areas) on the food chain presents a challenge for many investigations. Availability of metals in a potentially polluted soil and their possible transfer and bioaccumulation in sorrel (Rumex acetosa), spinach (Spinacia oleracea) and common nettle (Urtica dioica), were examined.
Some of the metrics are blocked by your
consent settings
ASSESSMENT OF TRACE ELEMENTS BIOAVAILABILITY – INGESTION OF TOXIC ELEMENTS FROM THE ATTIC DUST COLLECTED FROM THE VICINITY OF THE FERRO-NICKEL SMELTER PLANT
(Macedonian Academy of Sciences and Arts, 2017-04-10)
Bačeva Andonovska, Katerina
;
Stafilov, Trajče
;
Karadjova, Irina
<jats:p>The purpose of this study was to establish total and bioavailable contents of chemical elements in attic dust and their distribution in the area of the town of Kavadarci, Republic of Macedonia, and in this way to evaluate the exposure of population to toxic metals in areas with high industrial influences from the ferro-nickel smelter plant. The attic dust is derived predominantly from external sources such as aerosol deposits and soil dusting, and less from household activities. From that reason attic dust could be accepted as a tracer of historical aerosol pollution. All attic dust samples were analyzed for total and bioavailable element contents and their distribution in studied area. Several extraction agents recognized as representative for elements bioa-vailability assessment were applied to attic dust samples under investigations – phosphate buffer solutions that simulate human blood, for the simulation of lung inhalation carbonate buffer was used and 0.1 mol l–1 HCl solution to simulate stomach ingestion. A total of 18 elements (Ag, Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe K, Mg, Mn, Ni, Pb, Sr and Zn) were determined by atomic emission spectrometry with inductively coupled plas-ma (AES-ICP). The obtained results showed relatively high proportion of toxic elements bioavailability in the attic dusts samples from sites close to the metallurgical activities (Cr, Cu, Mn, Ni, Pb and Zn), most probably due to the small size and high reactivity of the particles of attic dust. As might be expected the highest leacha-ble amounts of toxic elements were found for Ni, Co, Cr and Pb from attic dust in the extraction solution of HCl (0.1 mol l–1 HCl) compared with the other 3 extraction media. Discussion on trace elements mobility and bioavailability related to environmental pollution and effects on human health are presented.</jats:p>
Some of the metrics are blocked by your
consent settings
Biomonitoring of air pollution with mercury in Croatia by using moss species and CV-AAS
(Springer Science and Business Media LLC, 2014-07)
Spirić, Zdravko
;
Vučković, Ivana
;
Stafilov, Trajče
;
Kušan, Vladimir
;
Bačeva, Katerina
Moss samples from four dominant species (Hypnum cupressiforme, Pleurozium schreberi, Homalothecium sericeum and Brachythecium rutabulum) were collected during the summer and autumn of 2010 from 121 sampling sites evenly distributed over the territory of Croatia. Samples were totally digested by using microwave digestion system, whilst mercury was analysed by using cold vapour atomic absorption spectrometry (CV-AAS). Descriptive statistics were done from analyses of mercury in all moss samples. The content of mercury ranged from 0.010 to 0.145 mg kg(-1) with a median value of 0.043 mg kg(-1). Hg distribution map shows the sites of the country with higher levels of this element. High contents of Hg were found in moss samples collected from the regions of Podravina and Istria as a result of anthropogenic pollution. Comparison of median values and ranges with those found in moss samples in 2006 shows slight reduction of mercury air pollution. When compared to the results obtained from recent studies conducted in Slovenia, Macedonia and especially in Norway-which serves as a reference considering the fact that it is a pristine area-mercury air pollution in Croatia is insignificant.

Faculty of Natural Sciences and Mathematics

Browse

Filters

Settings

Sort By

Results per page

Search Results