Introduction: Bacterial challenge in periodontal diseases activates both local and systemic immune responses of a macroorganism by increasing multiple proinflammatory factors that can be discovered in gingival crevicular fluid (GCF) and in saliva. We tested the hypothesis that IL-1&beta; concentration in GCF and saliva correlates with periodontal health and diseases.&nbsp; Materials and methods: The study included 62 people (mean age 36&plusmn;14 yrs), divided into three groups &ndash; patients with periodontitis (24 people), patients with gingivitis (19 people) and periodontally healthy people (19 people). Saliva and GCF samples were taken from all participants and the levels of IL-1&beta; in all samples were determined by ELISA. Results: IL-1&beta; concentrations in GCF of healthy individuals were significantly lower than the IL-1&beta; concentration in GCF of patients with gingivitis (p=0.009) and with periodontitis (p<0.0001). The IL-1&beta; concentrations in the saliva of healthy individuals were significantly lower than the IL-1&beta; concentrations in the saliva of pa-tients with gingivitis (p=0.002) and patients with periodontitis (p=0.025). Conclusions: Based on the obtained results, IL-1&beta; concentrations in GCF and saliva may be proposed as additional diagnostic criteria of inflammation in periodontal tissues, both at initial diagnosis and at diagnosis of recurrence of periodontitis, but further studies are needed to verify them as markers of periodontal diseases.

Matrix metalloproteinases play a fundamental role in tissue physiology, and in host responce and MMP-8 is considered to be indicator of periodontal diseases. This study aims to compare MMP-8 levels in saliva and Gingival crevicular fluid (GCF) in patients with periodontal health, plaque-induced gingivitis, and periodontitis to determine the potential of MMP-8 as a non-invasive marker for early diagnosis of periodontal disease. 62 individuals have been involved in the study, divided into three groups based on clinical and radiographic criteria -19 healthy subjects (H), 19 patients with plaqueinduced gingivitis (G) and 24 -with periodontitis (P). GCF from 6 sites and saliva were collected respectively in micropipettes and sterile tubes. The volume was determined. MMP-8 concentration was measured using ELISA. We found significant difference between the mean range of concentrations of MMP-8 in saliva in H and patients with G (p = 0.008). We determine MMP-8 in saliva as convenient for differentiation of periodontal health from plaque-induced gingivitis by logistic regression analysis. At the determined cut-off value of the biomarker MMP-8 in saliva -134 ng/ml, OR = 11.7 (95% confidence interval [CI]: 2.082 to 65.605) (p = 0.005), the sensitivity is 57.9%, and the specificity is 89.5%. The established data identify MMP-8 in saliva as a significant marker for the diagnosis of gingivitis. We recommend determining the concentration of salivary MMP-8 as a test that would provide objective data for differentiation plaque-induced gingivitis from periodontal health, based on the determined cut-off value.

The investigated fish pass is a part of а low-head hydrostatic pressure machine (HPM) located on an existing weir in the upper Iskar River. Monitoring of the hydraulic features of the fish pass was performed under different hydraulic conditions. Diversity and abundance of the local fish fauna was investigated with the aim to verify target fish species. A major limiting factor for using of the fish pass during flood periods was high water velocity (both inside the fish pass and at the fish pass downstream entrance), while during the low water discharge periods it was the insufficient water depth in some pools and the significant differences between the water levels in adjacent pools. The difference between the water levels at the entrance and exit of the fish pass reduces the chances for access of small-sized fish species. Some measures for improving fish pass functionality were developed. Several reconstruction solutions were proposed in an attempt to help solving the identified problems.

This study presents a coupled thermal-structural finite element analysis of a large concrete gravity dam in Bulgaria for exploring the dam response under different actual load combinations. The loads applied to the structure are caused by varying water level in the reservoir and ambient temperature typical for the respective seasons. The developed computational model was calibrated with real plumb measurements. Based on the performed analyses in the ANSYS environment, key limit values for the horizontal displacements measured by the plumbs in the dam as possibly caused by extreme combinations of ambient temperature and water level are formulated for further improvement of the dam operation.

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