Introduction Leptin is a cytokine-like hormone which has a complex role in inflammation. However, the importance of leptin in the pathogenesis of rheumatoid arthritis (RA) is far from being fully elucidated. The aim of the study was to determine serum leptin levels in RA patients and to evaluate whether there is an association between disease activity, anthropometric indices and leptin levels. Material and methods This hypothesis-generating study included 55 RA patients and 25 matched healthy subjects. The serum leptin concentration was determined by enzyme-linked immunosorbent assay (ELISA). Results Median serum leptin level in RA patients of 27.4 ng/ml (14.5–54.9 ng/ml) was statistically significantly higher (p = 0.03) compared with the median leptin value of 16.3 ng/ml (9.6–38.8 ng/ml) determined in healthy controls. The serum leptin level in the high disease activity group was significantly higher (p < 0.0005) than that in the low disease activity group and in healthy controls. A significant difference (p = 0.001) in serum leptin level was also found when the high disease activity group was compared with the moderate disease activity group. In the RA group a statistically significant positive correlation (rho = 0.390; p = 0.003) was observed between serum leptin level and disease activity score (DAS28). Conclusions The present results show that serum leptin levels are increased and significantly associated with disease activity in patients with RA and may have a valuable role in the inflammatory reactions and pathogenesis of RA.

Quality of life (QOL) is one of the most researched topics in the field of disability in the last 30 years. However, there are few studies that examined the QOL in relation to the type of disability and self-reported health status. The goal of the present study was to examine the QOL in people with disabilities in relation to the type of disability and self-reported health status. The sample for this study consisted of 286 people with disabilities who were interviewed using the Personal Outcomes Scale as a measure of QOL. The results of this study revealed statistically significant differences in the self-reported QOL between people with different types of disabilities. The results also revealed a moderating effect that self-reported health status had on QOL across disability categories. There were no interaction effects of self-reported health status and disability category on the QOL. Generally, people with intellectual disability reported lower QOL than people in other disability categories. Self-reported health status had a significant impact on the QOL across the disability groups. Non-governmental organizations can, through their policies and practices, enhance the person-referenced QOL outcomes.

Polymers based on polystyrene are widely used as thermoplastic materials due to the diversity in application, easy processability and a relatively low price. About 45% of the produced polystyrene is produced as compact and foamed products. Cellular foam polystyrene could be produced as expanded polystyrene (EPS) and extruded polystyrene (XPS) and is mainly used as insulation material. Therefore, physical and chemical properties of expanded and extruded polystyrene is of particular importance for thermal conductivity of the material. In this study, four types of expanded polystyrene were tested. Coefficient of thermal conductivity and the resistance of heat transfer were measured and compared to as well as mecahnical properties of the materials. It was confirmed that the density and thickness of the polystyrene influence the resistance of heat transfer.

In this paper, supercritical extraction of hyssop (Hyssopus officinalis L.) is performed by using carbon dioxide as extractant. Effect of pressure (80, 100 and 150 bar) on the yield of total extract at a temperature 313 K, flow 0.00323 kg/min and the average diameter of particles 0.49 mm is investigated. For modeling of extraction system hyssop – supercritical CO2, Naik's model is applied, where in the total yield of extract is determined. On the basis of the value of the correlation coefficient |r| (0.976 – 0.992), it was concluded that a very strong correlation was obtained between reciprocal values of the total extract yield and extraction time (1/y i 1/t), so it can be concluded that Naik's model can succesfully be applied for determining yield of total extract.

We reduce the exponent in the error term of the prime geodesic theorem for compact Riemann surfaces from $\frac{3}{4}$ to $\frac{7}{10}$ outside a set of finite logarithmic measure.