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The influence of microstructure and aluminum distribution on the corrosion of three different casts of the magnesium AM50 alloy (sand, graphite, die) was studied in 1.6 wt% NaCl solution. The microstructure of the alloys and the distribution of individual elements were characterized using scanning electron microscopy (SEM) and energy dispersive X-ray analyzes. Differences in the morphology and distribution of corrosion damage were determined using SEM and confocal scanning laser microscopy. Weight change measurements and electrochemical impedance spectroscopy showed that the corrosion resistance improved in the order sand cast < graphite cast ⪡ die cast. This increased resistance was shown to be attributable to the increasing tightness of the α-Mg/β-phase/Al-containing eutectic microstructural network, which led to an improved protection of the surface by Al-enriched eutectic and a decrease in the probability of initiating a major damage site on an a-Mg region with low A1 content. [ABSTRACT FROM AUTHOR]

The aim of this study is to determine the correlation between the state of oral and den tal health of permanent teeth of children aged from 12 to 15. The set goals were realized by means of dental health examinations of 435 pupils aged 12-15 of both sexes from elementary schools in the city of Stip - 291 pupils (181 males and 110 females) and from villages in the vicinity of Stip, total 181 (96 male and 85 female) pupils from rural-urban settlements. The subject of research are the index of oral hygiene (OHI index) and the index parameters for the frequency of dental caries (FDC). OHI index values ??shown in Table 1 and the corresponding graph suggest that for respondents from Stip it was 0.51, and for the pupils from surrounding neighborhoods 0.49; the differences in values ??obtained from tests between the two groups were statistically significant (r<0.01). The values??of the structure of FDC and FDC shown in Table 2 and the correspond ing graph suggests that for respondents from Stip it was 6.20 and for pupils from surrounding neighborhoods 6.77, with the statistically significant difference of values ??between both groups of (r<0.01). The same table and graph represented caries with 2.05 among respondents from Stip, and 3.54 among respondents from the surrounding neighborhoods; the differences in values ??between the two groups were statistically significant (r<0.10). Extracted teeth were covered with 0.82 among respondents from Stip and 1.05 among respondents from the surrounding neighborhoods. The differences in values ??between the two groups did not attain statistical significance (r<0.20). [ABSTRACT FROM AUTHOR]

Lake Ohrid, straddles the mountainous border between south-western Macedonia and eastern Albania. It is one of Europe's deepest and oldest lakes, preserving a unique aquatic ecosystem that is of worldwide importance, with more than 200 endemic species. Lakes are divided into subsections based on morphometric (depth, dimension, geology of shores, currents, etc.) and physicochemical (temperature, pH, oxygen content) parameters. Apart from their bacterial and algal populations, stream, rivers, and lakes also contain fungal, protozoan, and viral populations, which interact and contribute to the functioning of the food web. This paper presents pollution aspects of Lake Ohrid at Pogradec. Out of large number of microbial parameters linked with human health, some significant contaminating indicators, namely, total Coli form (MPN/100ml), Fecal coliform (MPN/100ml), Streptococcus feacalis (MPN/100ml) have been identified and measured. Eight sampling locations were selected, three of them in Pogradec city area, (three different bands in each sampling locations) and total of samples sets were collected over a period of three months from June to September. The results taken by the analyses show that the bacterial pollution of the littoral waters of Lake Ohrid, surpasses the UNEP/WHO standards for the microbiological quality of bathing waters (100-1000 E.coli/100ml) in most of the sampling locations. [ABSTRACT FROM AUTHOR]

Dermatoglyphic prints were collected from 800 inhabitants of Dukagjin valley in Kosovo. The sample consisted of two ethnically different sub-populations who refer themselves as Albanians (N=400) and Turks (N=400). Qualitative analysis of prints concerned the frequency of the patterns on fingers (arch, ulnar and radial loop, whorl, accidental whorl) and on palms (Thenar and I, II, III, and IV interdigital area and the hypothenar, main line index, and the axial »t« triradius position). As was expected due to previous study of quantitative dermatoglyphic traits, in the same population the Albanians and Turks showed to be significantly different in most explored qualitative dermatoglyphic variables. Found differences indicated that the reproductive isolation between the Albanian and Turkish population in Kosovo is substantial, despite the fact that those two ethnic sub-populations live in the close vicinity through several centuries. [ABSTRACT FROM AUTHOR]

Strongly coupled diffusion has been reported for fluxes of solutes that differ significantly in molecular size. According to the excluded-volume model, a solute increases the effective concentrations of other solutes by reducing the volume of solution they can occupy. The flux of solute 2 produced by the gradient ∇c1 in the concentration of solute 1 is interpreted as the ordinary diffusion of solute 2 down its effective concentration gradient. Cross-diffusion coefficient D21 = D22c2V1,eff /(1 - c1V1,eff)2 is predicted, where V1,eff is the effective molar volume of solute 1. This model does not account for countercurrent coupled diffusion (D21 < 0) and is found to be inconsistent with the Onsager reciprocal relation (ORR). A thermodynamic model of coupled transport is developed by approximating the flux of solute i as the product of its concentration, mobility, and chemical potential gradient driving force (-∇μi), which gives D21 = D22c2(V1 - V0)/[1 - c1(V1 - V0)], where Vi is the partial molar volume of component i and the solvent is component 0. For dilute solutions with V1 ≫ V0, the thermodynamic prediction D21 ≉ c2V1D22 and the excluded-volume prediction D21 ≉ c2V1,effD22 are qualitatively similar, but the thermodynamic model does not require the assumption of effective concentrations or effective volumes, provides a physical explanation for coupled diffusion, and is consistent with the ORR. Moreover, because ∂μ2/∂c1 is proportional to V1 - V0, the thermodynamic model suggests that a concentration gradient in solute 1 can drive co-current or counter-current flows of solute 2, depending on the relative volumes of solute 1 and solvent 0. These features are illustrated by comparing measured and predicted Dik coefficients for solutions of n-octane(1) + n-hexadecane(2) in n-dodecane(0) at nine different compositions at 25 °C. [ABSTRACT FROM AUTHOR]