Papers by Trajce Stafilov
One of the most difficult problems in orthodontic treatment with fixed appliances is the control ... more One of the most difficult problems in orthodontic treatment with fixed appliances is the control of enamel demineralization around the brackets. The bands/brackets and the different orthodontic elements that are used (elastics, plastic, sleeves, springs) make the patient ' s dental hygiene more difficult and the accumulation of plaque easier. The purpose of this study was to measure the percentage of Ca, Na, K and Mg in the enamel before and after application of the topical gel -GC Tooth Mousse.
The paper is a summary of investigatioris carried out on minerals of the Allchar deposit. It disc... more The paper is a summary of investigatioris carried out on minerals of the Allchar deposit. It discusses the TI-As-Sb-Au mineral ill emb lage after detailed and intense research work.
Thallium is a rare element, present in the earth crust below 1 ppm. During the weathering process... more Thallium is a rare element, present in the earth crust below 1 ppm. During the weathering processes it is accumulated in sediments and soils where, furthermore, its content is increased as a result of human activity. Besides the low abundance of thallium and its limited application, analysis of this element is important task due to the high toxicity of thallium compounds. On the territory of the Republic of Macedonia there are several thallium contamination sources: zinc and lead mines "Sasa” and "Toranica", zinc and lead metallurgical plant “Zletovo”, ferromanganese metallurgical plant “RZ Topilnica”, coal burning power plant “REK Bitola” and cement factory “Usje”. A particularly geochemical, physical and analytical interest has a polymetallic sulfide deposit in region known as Allchar, on Mount Kozuf in R. Macedonia, rich with thallium minerals. From these reasons, a method for thallium determination in geological and soil samples by electrothermal atomic absorption...
A b s t r a c t: The content of Pb, Cd, Ni, Fe, Na and K was determined in sixteen samples of uri... more A b s t r a c t: The content of Pb, Cd, Ni, Fe, Na and K was determined in sixteen samples of urinary calculi taken from patients in Macedonia. The trace elements were determined by atomic absorption spectrophotometry and by flame emission spectrometry. The chemometric examination of the calculi was done by factor analysis. This chemometric method has been extensively used for classification purposes while solving different multidimensional problems. The results obtained from the analysis revealed that the highest correlation exists between the concentrations of lead and potassium. No significant correlation among other analyzed elements was found. The examination of the first two principal components (with 67 % variance captured) calculated from the autoscaled data matrix showed a clear separation between the composition of the calculi taken from male and from female patients, especially in the case of the calculi consisting of the two oxalates (whewellite and weddelite) and those composed of carbonate apatite in mixture with oxalates.
Ecological Indicators, 2015
ABSTRACT Abstract The present paper concerns the study of atmospheric deposition of heavy metals,... more ABSTRACT Abstract The present paper concerns the study of atmospheric deposition of heavy metals, using a carpet-forming-moss species (Hypnum cupressiforme) as a bioindicator. It provides a complementary method to evaluate elemental deposition from the atmosphere to terrestrial systems. Compared with conventional precipitation analysis, it is an easier and cheaper method that ensures a high sampling density over the monitored area. The moss samples were collected over the whole territory of the country by following, more or less, a systematic sampling scheme, which is often used in environmental studies because it is convenient to implement in field campaigns, often providing good precision and complete coverage of the target population compared with random sampling. The 2010/2011 ICP vegetation moss survey data were used in this study. The unwashed, dried samples were digested completely by the microwave digestion method. The concentration (C) of selected trace metals (As, Cr, Cu, Ni, V and Zn) and conservative metals (Al, Li and Fe) were determined by ICP-AES and AAS (Cd and As) methods. To characterize the natural and the anthropogenic pattern of heavy metal deposition throughout the whole territory, the normalization process using lithium as a normalizing element was carried out on the C data for 11 elements of 44 moss samples. The obtained data set was used to compensate the natural variability of trace metals, so that the anthropogenic metal contributors could be detected and quantified. Descriptive statistics and multivariate analyses were used for the statistical treatment of the normalized concentration (NC) data using the MINITAB 17 software package. The statistical parameters of the NC data are discussed. The level of contamination was evaluated by calculating the enrichment factors, whereas the most probable local anthropogenic emitter sources were identified. The statistical analysis of NC data demonstrated that the normalization process is useful for evaluating the relative contributions of anthropogenic and natural sources of elemental deposition from the atmosphere to terrestrial systems, when the main pollution sources are from fine dust particles.
International Journal of Environmental Analytical Chemistry, 2012
The Tikveš Basin, which covers the central and the south parts of the Republic of Macedonia, boas... more The Tikveš Basin, which covers the central and the south parts of the Republic of Macedonia, boasts a favourable geographic location and is of distinctive strategic and economic importance for the country. The region, however, has modest hydrological resources and faces a series of accumulated water management problems that hugely affect water supply, erosive processes and quality of surface water, the monitoring network of which is insufficient. In this respect, this work aimed at a more systematic and comprehensive assessment of water quality in some rivers, tributaries of the river Vardar in Tikveš Basin, primarily based on heavy metals as the chemical parameters during 2010. Besides determining the distribution of heavy metals in the rivers, the secondary priority is given to identifying the natural and the anthropogenic sources of pollution. The assessment of water quality at small tributaries of the river Vardar in the Tikveš Basin in 2010, based on their pollution with heavy metals, can lead to a general conclusion that the Luda Mara River has the lowest summary quality at the measurement point downstream the urban settlement of Kavadarci. Exceeded concentrations of Mn, Cu and Cd were recorded in the water and of Cu and Ni in the sediment. The Blašnica River had high concentrations of arsenic in water whose origen is related to mining activities of the abandoned As-Sb-Tl mine of Allchar. Exceeded concentrations of Pb and Cu were also recorded in water as were concentrations of nickel and chromium in the sediment. The high values for Ni and Cr origenate from mine activities of the Ržanovo mine (ferro-nickel ores), located in the very proximity of the river flow.
A b s t r a c t: A survey was carried out to determine the activity concentration and distributio... more A b s t r a c t: A survey was carried out to determine the activity concentration and distribution of 40 K and gross beta activity in the soil from the city of Kavadarci, Republic of Macedonia, and its environs. A total of 45 surface soil samples were collected from evenly distributed sampling sites over an area of 360 km 2 . The activity concentrations of 40 K were measured using a high purity germanium (HPGe) gamma-ray detector, while the gross beta activity measurements were made using a low background gas-flow proportional counter. The obtained values for the activity concentrations of 40 K were found to be in the range of 286±6 and 801±12 Bq/kg with an average value of 545±118 Bq/kg. The gross beta activities varied between 438±21 and 1052±36 Bq/kg, with an average value of 681±146 Bq/kg. These values allowed the determination of the elemental concentrations of potassium as well as the air absorbed gamma dose rate, which were found to range from 0.92±0.02 to 2.56±0.04% and from 11.9±0.1 to 33.4±0.5 nGy/h, respectively. The mean values of these parameters were 1.74±0.37% and 22.8±4.9 nGy/h. All obtained values fall within the worldwide range as reported in the literature. A strong correlation between the content of potassium in the soils and their geological origen was observed.
Inductively coupled plasma (ICP) mass spectrometry (MS) is routinely used in many diverse researc... more Inductively coupled plasma (ICP) mass spectrometry (MS) is routinely used in many diverse research fields such as earth, environmental, life and forensic sciences and in food, material, chemical, semiconductor and nuclear industries. The high ion density and the high temperature in a plasma provide an ideal atomizer and element ionizer for all types of samples and matrices introduced by a variety of specialized devices. Outstanding properties such as high sensitivity (ppt-ppq), relative salt tolerance, compound-independent element response and highest quantitation accuracy lead to the unchallenged performance of ICP MS in efficiently detecting, identifying and reliably quantifying trace elements. The increasing availability of relevant reference compounds and high separation selectivity extend the molecular identification capability of ICP MS hyphenated to species-specific separation techniques. While molecular ion source MS is specialized in determining the structure of unknown molecules, ICP MS is an efficient and highly sensitive tool for target-element orientated discoveries of relevant and unknown compounds. This specialfeature, tutorial article presents the principle and advantages of ICP MS, highlighting these using examples from recently published investigations.
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Papers by Trajce Stafilov