Determination of regional flow duration curves

Bu çalışmada, bölgesel ölçekte hidroelektrik potansiyelin belirlenmesinde akım ölçüm değeri olmayan veya eksik olan yerlerde proje debisinin belirlenmesi için hiyerarşik ve hiyerarşik olmayan küme analiz (cluster analysis) yöntemleri kullanılarak bölgesel debi süreklilik eğrilerinin elde edilebileceği ortaya konmuştur. Küme analiziyle oluşturulan homojen bölgelere ait sınırların, veri olarak kullanılan özgül debi değerlerinin standart hale getirilip getirilmemesine, özgül debi süreklilik eğrisinin kullanılan aralığına ve küme analiz yöntemine bağlı olarak değiştiği belirlenmiştir. Doğal akışlı hidroelektrik santraller için debi süreklilik eğrisinin aşılma olasılığı %30-%100 olan aralığının kullanılmasının uygun olması sebebiyle bu aralıktaki veriler standart hale getirilerek küme analiziyle bölgesel debi süreklilik eğrileri elde edilmiştir.Anahtar Kelimeler: Doğal akışlı hidroelektrik potansiyel, bölgesel debi süreklilik eğrisi, küme analizi.This study shows that regional flow duration curves can be obtained by means of methods of hierarchical or non-hierarchical cluster analysis in order to determine the design flow values of the regional hydroelectric potential where measured flow data do not exist or is incomplete/inadequate. It is determined that change of the boundaries of homogenous sub-regions depends on whether making or not making standard the specific flow duration curve values being used as data, and the used interval of specific flow duration curve and cluster analysis methods. The regional flow duration curves are obtained, because it is appropriate for natural flow hydropower plants to use the probability of excess of flow duration curve, which is 30%-100%, with cluster analysis by making data in that interval standard. When the homogeneous regions formed in terms of specific flow duration curves with hierarchical and nonhierarchical cluster analysis methods by using the data used in this study are compared, it was observed that complete linkage method and Ward method within hierarchical methods and k-means method within nonhierarchical methods yield closer results to each other. The results obtained by using single linkage, median linkage, centroid linkage, average linkage, and weighted average linkage methods within other nonhierarchical methods could not be found applicable and meaningful in terms of flow duration relations.Keywords: Hydroelectric potential of natural flow, regional flow duration curve, cluster analysis

Maternal serum interlukin-6 level in preterm labor

Objective: The aim of this study was to measure interleukin-6 (IL-6) levels in maternal serum of women undergoing preterm labor without a clear infection. Materials and Methods: Twenty two pregnant women with diagnosis of preterm labor who presented to the outpatient clinic of 19 Mayıs University Faculty of Medicine from July 2011 through December 2011 were enrolled in the study group. Twenty two healthy pregnant women who were at the same gestational age as the study group were selected as the control group. Results: Gestational age in the study and control groups varied from 24 weeks and 4 days to 34 weeks and 6 days. In the study group, 11 patients (50%) underwent preterm birth. Pregnant women in preterm labor were compared to healthy pregnant women with regards to serum IL-6 levels. No significant difference was found in the IL-6 levels of maternal serum between the 2 groups. Conclusion: In this study, we have shown that there is no increase in IL-6 levels in patients undergoing preterm labor without clinical or biochemical infection signs

The effect of ellagic acid on the repair process of periodontal defects related to experimental periodontitis in rats

Objective: This study aims to evaluate the effect of ellagic acid (EA) by measuring the levels of alveolar bone resorption and inflammatory and oxidative stress markers in the periodontal tissues and serum on the periodontal repair process related to experimental periodontitis in rats. Methodology: Forty Wistar rats were divided into four study groups as follows: Group 1=healthy control (n=10); Group 2=EA control (15 mg/kg)(n=10); Group 3=periodontitis (n=10); Group 4=periodontitis+EA (15 mg/kg) (n=10). The periodontitis model was established by ligating bilateral mandibular first molars for 14 days. Then, rats were given normal saline or EA for another 14 days by gavage administration. Serum and gingiva myeloperoxidase (MPO) activity, 8-hydroxydeoxyguanosine(8-OHdG), and glutathione (GSH) levels were analyzed by ELISA. İmmunohistochemical analysis was used to detect Interleukin (IL)-6, IL-10, and tumor necrosis factor-alpha (TNF-α) immunoreactivities in the periodontal tissues. Alveolar bone loss (ABL) and attachment loss (AL) was evaluated by histomorphometry analysis. Results: ABL and AL were statistically higher in group 3 than in groups 1, 2 and 4 and in group 4 than in groups 1 and 2 (p<0.05). MPO activities in gingival tissue and serum were significantly increased in group 3 compared to groups 1 and 2 (p<0.05). Significantly higher serum GSH levels, lower gingiva, and serum 8-OHdG levels, and MPO activity were observed in group 4 compared to group 3 (p<0.05). Rats with periodontitis (group 3) expressed significantly higher immunoreactivities of IL-6 and TNF-α and lower IL-10 immunoreactivity compared to those other groups (p<0.05). IL-6 and TNF-α immunoreactivities significantly decreased and IL-10 immunoreactivity increased in group 4 after the use of EA compared to group 3 (p<0.001). Conclusions: Our findings showed that EA provides significant improvements on gingival oxidative stress and inflammatory markers and alveolar bone resorption in the repair process associated with experimental periodontitis. Therefore, EA may have a therapeutic potential on periodontitis

Effects of evening primrose oil and 5-fluorouracil on the healing of colonic anastomoses in rats

Aim: This study was designed to evaluate the efficacy of evening primrose oil (EPO) on colonic anastomosis. Methods: Sixty rats with colonic anastomosis were randomly divided into six groups. EPO and 5-Fluorouracil (5-FU) were administered at doses of 5 g/kg/day and 20 mg/kg/day, respectively.  Group 1 served as sham control. The rats in Group 2 (EPO) received EPO (14 days preoperatively), in Group 3 (Extended EPO) received EPO (14 days preoperatively and 7 days postoperatively), in Group 4 (5-FU) received intraperitoneally 5-FU (5 days preoperatively), in Group 5 (5-FU+EPO) received EPO (14 days preoperatively), and 5-FU (5 days preoperatively), in Group 6 (5-FU+ extended EPO) received EPO (14 days preoperatively and 7 days postoperatively)  and 5-FU (5 days preoperatively). Histopathological examination, bursting pressure, and hydroxyproline content were used for evaluation. Results: Significant differences were found between the Groups 1, 2, and 3 and Groups 4, 5, and 6 in bursting pressures. Polymorphonuclear leukocyte (PMNL) and lymphocyte infiltration was significantly less in group 3, compared to the control and group 2. The least PMNL infiltration was in group 6 compared to groups 4 and 5.  The hydroxyproline level was different in group 3 compared to the control and group 2. Furthermore, groups 5 and 6 were different compared to group 4. Conclusion: EPO had favorable effects on colonic anastomosis even in groups where 5-FU was used

Comparison of gingival crevicular fluid and serum human beta-defensin-2 levels between periodontal health and disease

Background The aim of this study was to evaluate the levels of serum and gingival crevicular fluid (GCF) human beta-defensin-2 (hBD-2), an antimicrobial peptide that takes roles in inflammatory diseases, in patients with chronic periodontitis (CP). Subjects and Methods A total of one hundred and one individuals, 59 controls and 42 patients with CP, participated in this study. Clinical index measurements were recorded during the periodontal examination, and radiographic evaluation was also performed. The serum and gingival crevicular fluid (GCF) samples were taken from all of the participants, and the hBD-2 levels were determined biochemically by enzyme-linked immunosorbent assay (ELISA). Results In our study, hBD-2 GCF levels in CP (stages II-IV periodontitis based on the new 2018 classification of periodontal diseases) group (2.77 ng/30 s) were higher than in the periodontally healthy (2.51 ng/30 s;p = .047) individuals. In contrast, serum hBD-2 levels in CP (2.92 ng/ml) were lower compared with those in healthy controls (7.75 ng/ml,p < .001). Conclusion Interestingly, our results showed that while higher hBD-2 GCF levels are associated with CP, lower serum hBD-2 levels were detected in CP

Serum vitamin D concentration is associated with antimicrobial peptide level in periodontal diseases

Objective: The aim of the study was to assess whether or not Vitamin D deficiency was associated with the GCF and gingival tissue antimicrobial peptides (AMP), namely, human beta defensin-2 (hBD-2) and cathelicidin (LL-37) level in chronic periodontitis (CP) and gingivitis patients

Relationship between gingival inflammation and total glutathione

Aim: Glutathione, which is known to be the main antioxidant, is the foremost redox regulator in the control of inflammatory processes. The goal of this study was to investigate the levels of total glutathione, which plays a central role in cellular antioxidant defense, in the gingival crevicular fluid (GCF) and plasma of individuals with gingivitis and periodontally healthy. Materials and Methods: Fifteen periodontally healthy subjects and 15 individuals with gingivitis were enrolled in the study. Samples of GCF, plasma, and clinical measurements were attained before and one month after non-surgical periodontal therapy. GCF and plasma levels of total glutathione were analyzed using spectrophotometric assay. Results: It was found that the levels of total glutathione in GCF were lower in gingivitis group than those in the periodontally healthy group (P0.05). Also, a statistically significant rise in GCF and plasma total glutathione levels in gingivitis group was found after periodontal therapy compared to baseline (P<0.05). Furthermore, there was a negative correlation between total glutathione and gingival index (P<0.05). Conclusion: Findings of this study showed that GCF and plasma levels of total glutathione could be influenced by gingival inflammation. In addition, it was revealed that the importance of periodontal therapy in the patients with gingivitis

The role of bioelectrical impedance analysis, NT-ProBNP and inferior vena cava sonography in the assessment of body fluid volume in children with nephrotic syndrome

Background: Assessment of volume status and differentiating “underfill” and “overfill” edema is essential in the management of patients with nephrotic syndrome (NS). Objectives: Our aim was to evaluate the volume status of NS patients by using different methods and to investigate the utility of bioelectrical impedance analysis (BIA) in children with NS. Methods: The hydration status of 19 patients with NS (before treatment of NS and at remission) and 25 healthy controls was assessed by multifrequency BIA, serum N-terminal-pro-brain natriuretic peptide (NT-proBNP) levels, inferior vena cava (IVC) diameter, left atrium diameter (LAD) and vasoactive hormones. Results: Renin, aldosterone levels, IVC diameter and LAD were not statistically different between the groups. NT-proBNP values were statistically higher in the attack period compared to remission and the control group (p = 0.005 for each). Total body water (TBW), overhydration (OH) and extracellular water (ECW) estimated by the BIA measurement in the attack group was significantly higher than that of the remission group and controls. There were no significant correlations among volume indicators in group I and group II. However, significant correlations were observed between NT-proBNP and TBW/BSA (p = 0.008), ECW/BSA (p = 0.003) and ECW/ICW (p = 0.023) in the healthy group. TBW was found to be higher in patients with NS in association with increased ECW but without any change in ICW. NT-proBNP values were higher in patients during acute attack than during remission. Conclusions: Our findings support the lack of hypovolaemia in NS during acute attack. In addition, BIA is an easy-to-perform method for use in routine clinical practice to determine hydration status in patients with NS