122 results match your criteria: "University "Sts. Cyril and Methodius" Skopje[Affiliation]"

Three different bioactive materials suitable as dentine substitutes in tooth repair have been studied: glass-ionomer cement, particulate bioglass, and calcium-silicate cement. On 15 permanent human molars, Class V cavities were prepared and the bottom of each cavity was de-mineralized by an artificial caries gel. After the de-mineralization, the teeth were restored with: (1) Bioglass®45S5 and ChemFil® Superior; (2) Biodentine™ and ChemFil® Superior; and (3) ChemFil® Superior for a complete repair.

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Remineralization of hard dental tissues is thought to be a tool that could close the gap between prevention and surgical procedures in clinical dentistry. The purpose of this study was to examine the remineralizing potential of different toothpaste formulations: toothpastes containing bioactive glass, hydroxyapatite, or strontium acetate with fluoride, when applied to demineralized enamel. Results obtained by scanning electron microscopy (SEM) and SEM/energy dispersive X-ray analyses proved that the hydroxyapatite and bioactive glass-containing toothpastes were highly efficient in promoting enamel remineralization by formation of deposits and a protective layer on the surface of the demineralized enamel, whereas the toothpaste containing 8% strontium acetate and 1040 ppm fluoride as NaF had little, if any, remineralization potential.

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Effect of winemaking treatment and wine aging on phenolic content in Vranec wines.

J Food Sci Technol

April 2012

Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Sts Cyril and Methodius University, Arhimedova 5, 1000 Skopje, Republic of Macedonia ; Department for Enology, Institute of Agriculture, Sts Cyril and Methodius University, Aleksandar Makedonski bb, Skopje, Republic of Macedonia.

Phenolic compounds and colour stability of red wines produced from Vranec Vitis vinifera L. grape variety were investigated by means of different maceration times (3, 6 and 10 days), two doses of SO2 (30 and 70 mg/L SO2), two yeasts for fermentation (Vinalco and Levuline), temperature of storage and time of aging (3, 6 and 16 months). In general, maceration time influenced the phenolics extraction from the grapes into the wine.

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Renal replacement therapy in Europe-a summary of the 2010 ERA-EDTA Registry Annual Report.

Clin Kidney J

February 2013

ERA-EDTA Registry, Department of Medical Informatics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.

Background: This study provides a summary of the 2010 European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry Annual Report (available at www.era-edta-reg.org).

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Anharmonic vibrational frequency shifts of the phenol(+) O-H stretching mode upon complex formation with the open-shell ligand O(2) were computed at several DFT and MP2 levels of theory, with various basis sets, up to 6-311++G(2df,2pd). It was found that all DFT levels of theory significantly outperform the MP2 method with this respect. The best agreement with the experimental frequency shift for the hydrogen-bonded minimum on the potential energy surfaces was obtained with the HCTH/407 functional (-93.

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This work was afforded from 2 points of view, phytochemical evaluation and relation to antioxidant activity and dietary burden of phenolics of a cup of "Mountain tea", a drink obtained by domestic infusion of Sideritis. Phytochemically, two extraction protocols using water and methanol as solvent were used for comparison. Methanol and boiling water extracts (by domestic infusion procedure) showed that extracts were rich in bound forms of phenolics such as hydroxycinnamic acids, phenylethanoid glycosides and flavonoid glycosides.

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Comparison of different extraction solvent mixtures for characterization of phenolic compounds in strawberries.

J Agric Food Chem

May 2011

Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Sts Cyril and Methodius University, Skopje, Republic of Macedonia.

Eight different solvent mixtures containing acetone or methanol pure or combined with an acid (acetic, formic, hydrochloric) were tested for their efficiency for extraction of phenolic compounds from strawberries belonging to five groups of polyphenols: anthocyanins, flavonols, flavan-3-ols, hydroxycinnamic acid derivatives and conjugated forms of ellagic acid. Twenty-eight compounds from these five groups have been detected and quantified using HPLC-DAD-ESI-MS(n). The yield of each phenolic compound and group was evaluated with regard to the extraction solvent composition.

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This study sought to evaluate the effect of low-level laser treatment combined with scaling and root planing (SRP) on gingival tissue levels of TNF-alpha in subjects with periodontal disease. Eighty gingival papilla biopsy samples were obtained from 60 patients diagnosed with chronic advanced periodontitis; randomly assigned to three treatment groups (n = 20), as well as 20 subjects with no periodontal disease (group A). Group B received SRP on a single quadrant/day for four consecutive days.

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Arsenic in surface soils affected by mining and metallurgical processing in K. Mitrovica region, Kosovo.

Int J Environ Res Public Health

November 2010

Institute of Chemistry, Faculty of Science, Sts. Cyril and Methodius University, POB 162, 1001 Skopje, Macedonia.

The results of a study on the spatial distribution of arsenic in topsoil (0-5 cm) over the K. Mitrovica region, Kosovo, are reported. The investigated region (300 km(2)) was covered by a sampling grid of 1.

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Risk factors for Toxoplasma infection in pregnant women in FYR of Macedonia.

Parasite

September 2010

Institute of Microbiology and Parasitology, School of Medicine, University "Sts Cyril and Methodius", Skopje, FYR of Macedonia.

The aim of the study was to identify risk factors for Toxoplasma gondii infection in pregnant women in FYR of Macedonia. Retrospective analysis of serological and epidemiological data in a series of 235 pregnant women from Macedonia, tested for Toxoplasma infection between January 2004 and December 2005, showed an overall prevalence of infection of 20.4%.

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Al3+, Ca2+, Mg2+, and Li+ in aqueous solution: calculated first-shell anharmonic OH vibrations at 300 K.

J Chem Phys

November 2010

Institute of Chemistry, Faculty of Science, Sts. Cyril and Methodius University, P.O. Box 162, 1000 Skopje, Republic of Macedonia.

The anharmonic OH stretching vibrational frequencies, ν(OH), for the first-shell water molecules around the Li(+), Ca(2+), Mg(2+), and Al(3+) ions in dilute aqueous solutions have been calculated based on classical molecular dynamics (MD) simulations and quantum-mechanical (QM) calculations. For Li(+)(aq), Ca(2+)(aq), Mg(2+)(aq), and Al(3+)(aq), our calculated IR frequency shifts, Δν(OH), with respect to the gas-phase water frequency, are about -300, -350, -450, and -750 cm(-1), compared to -290, -290, -420, and -830 cm(-1) from experimental infrared (IR) studies. The agreement is thus quite good, except for the order between Li(+) and Ca(2+).

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Variable-delay feedback control of unstable steady states in retarded time-delayed systems.

Phys Rev E Stat Nonlin Soft Matter Phys

January 2010

Institute of Physics, Faculty of Natural Sciences and Mathematics, Sts. Cyril and Methodius University, Skopje, Macedonia.

We study the stability of unstable steady states in scalar retarded time-delayed systems subjected to a variable-delay feedback control. The important aspect of such a control problem is that time-delayed systems are already infinite-dimensional before the delayed feedback control is turned on. When the frequency of the modulation is large compared to the system's dynamics, the analytic approach consists of relating the stability properties of the resulting variable-delay system with those of an analogous distributed-delay system.

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The performance of some recently proposed DFT functionals by Truhlar's group (mPW1B95, mPWLYP1W, PBELYP1W, and PBE1W [Dahlke, E. E.; Truhlar, D.

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Nearest-neighbour-interaction model in the coupled-optical-phonon-mode theory of the infrared dispersion in monoclinic crystals: Application to Tutton salt single crystal.

Spectrochim Acta A Mol Biomol Spectrosc

May 2010

University of Sts. Cyril and Methodius, Faculty of Natural Sciences and Mathematics, Institute of Chemistry, Arhimedova 5, 1000 Skopje, Republic of Macedonia.

The coupled-optical-phonon-mode theory of Barker and Hopfield of two mode interaction in isotropic crystals has been extended to monoclinic crystals. The analytical expressions for the calculation of the dielectric tensor elements in the ac crystal plane have been derived. It has been shown that the interaction dielectric model is a generalized expression of the dielectric tensor for monoclinic case when no interaction between modes is present.

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The results of a first systematic study of spatial distribution of different elements in surface soil over the Veles region (50 km(2)) known for its lead and zinc industrial activity in the recent past are reported. A total of 201 soil samples were collected according to a dense net in urban area and less dense net in rural area. The total of 42 elements were analyzed by epithermal neutron activation analysis (ENAA) and by atomic absorption spectrometry (AAS).

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The aim of this study was to identify noise exposure indicators during day and night in the city of Skopje and to see if there is an association between these noise exposure indicators and annoyance. We have performed noise measurements and interviewed 510 adult subjects, using a questionnaire, prepared according to the ISO/TS-15666 standard. Average noise level over the day (Lday) was (62+/-6.

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HPLC method for determination of verapamil in human plasma after solid-phase extraction.

J Biochem Biophys Methods

April 2008

Institute of Chemistry, Faculty of Science, Sts. Cyril and Methodius University, POB 162, 1000 Skopje, Republic of Macedonia.

A simple, rapid and precise HPLC method has been developed for the assay of verapamil in human plasma. The clean up of the plasma samples was tested using several adsorbents for solid-phase extraction and best recovery was obtained using mixed-mode cartridges (HLB - hydrophilic-lipophilic balance) ranging between 94.70 and 103.

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A variety of benzamidomethyl derivatives were prepared in water under alkaline conditions (pH>9) via reaction of (benzamidomethyl)triethylammonium chloride (1) with different inorganic nucleophiles. Reaction of 1 with hydroxylamine did not give the expected mono(benzamidomethyl)-hydroxylamine (3) but rather gave N,N- di(benzamidomethyl)hydroxylamine (2). Reactions of 1 with sodium azide and potassium cyanide gave benzamidomethyl azide (4a) and benzamidomethyl cyanide (4b) respectively.

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Contents of Zn, Cu, Fe, Mn, Cd, Na, K, Ca and Mg in 123 honey samples from different regions of the Republic of Macedonia were determined by atomic absorption spectrometry. A microwave digestion system was applied for digestion of the samples. The mean content for the elements determined was found to be: 2.

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Flavonoids obtained from Sideritis species (Lamiaceae), S. raeseri and S. scardica, grown in Macedonia were studied.

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For the first time the atmospheric deposition of trace metals was studied over the entire territory of the Republic of Macedonia. Samples of the terrestrial mosses Hypnum cupressiforme, Camptothecium lutescens, and Homalothecium sericeum were collected in September-October 2002 at 73 sites evenly distributed over the country, and a total of 43 elements were determined by instrumental neutron activation analysis and atomic absorption spectrometry. Principal component factor analysis was used to identify the most polluted areas and characterize different pollution sources.

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Classification of perovskites with supervised self-organizing maps.

Anal Chim Acta

July 2007

Institute of Chemistry, Faculty of Natural Sciences and Mathematics, University Sts. Cyril and Methodius, P.O. Box 162, 1001 Skopje, Macedonia.

In this work supervised self-organizing maps were used for structural classification of perovskites. For this purpose, structural data for total number of 286 perovskites, belonging to ABO3 and/or A2BB'O6 types, were collected from literature: 130 of these are cubic, 85 orthorhombic and 71 monoclinic. For classification purposes, the effective ionic radii of the cations, electronegativities of the cations in B-position, as well as, the oxidation states of these cations, were used as input variables.

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Polarized IR reflectance spectra of the monoclinic single crystal K2Ni(SO4)2.6H2O: dispersion analysis, dielectric and optical properties.

Spectrochim Acta A Mol Biomol Spectrosc

February 2008

Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Sts. Cyril and Methodius University, Arhimedova 5, 1000 Skopje, Macedonia.

Polarized IR reflectance spectra of K2Ni(SO4)2.6H2O single crystal (belonging to the group of Tutton salts) were recorded at near-normal incidence. From the dispersion analysis performed on the spectra recorded from the ac crystal plane, mode parameters: transversal frequency, oscillator strength, attenuation constant and the orientation of the transition moment were determined.

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Isosbestic-like point in the polarized reflectance spectra of monoclinic crystals--A quantitative approach.

Spectrochim Acta A Mol Biomol Spectrosc

November 2007

Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Sts Cyril and Methodius University, Arhimedova 5, 1000, Skopje, Macedonia.

If two overlapping bands originate from transition moments that are perpendicular and lie along the principal axes of the infinity frequency dielectric tensor, an isosbestic-like point (ILP) appears in the overlaid polarized IR reflectance spectra of single crystals. These conditions can also be met in principle in case of the reflectance from the ac-plane of a monoclinic crystal despite of the crystal's low symmetry. In order to determine the transition moment directions, diagonalization of the infinity frequency dielectric tensor should be performed.

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Background: Cardiovascular diseases are the most common causes of death among hemodialysis (HD) patients, yet the risk factors for these events have not been well established. Our study objective was to determine predictors of cardiovascular mortality, considering the non-traditional/disease-related and treatment-related/ cardiovascular risk factor in HD patients.

Material And Methods: Disease-related cardiovascular risk factors, such as anaemia, calcium-phosphate disorders, nutrition-inflammation and treatment/dialysis-related cardiovascular risk factors such as HD dose, using the index Kt/V were analyzed in 214 patients on HD.

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