Browsing by Author "Turan, A"

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    Optimal Bidding Strategy of a Pumped Hydro Energy Storage Integrated Nuclear Power Plant considering Possible Outage
    Uguz, F; Turan, A; Gökçek, T; Ates, Y; Erdinç, O
    Recently, harmful gases emitted into the atmosphere disrupt the balance of nature and cause climate changes. The tendency towards renewable energy is increasing in order to prevent climate change. The importance of the conventional power plants in the power system is maintained due to the intermittent nature of renewable energy sources. In this regard, nuclear power which is one of the conventional power plants takes attention. In this study, a new approach for optimal scheduling of a Pumped Hydro Energy Storage (PHES) integrated Nuclear Power Plant (NPP) system is proposed. It is expected that PHES provides significant economic contribution to the grid operator especially by ensuring energy supply security of the NPP. Two different market types named Day Ahead Market (DAM) and Balancing Market (BM) in Turkey are implemented in the trades by using real electricity prices obtained from Energy Exchange Istanbul (EXIST), which is Energy Market Operator in Turkey. In order to evaluate the effectiveness of the proposed model, seasonal impacts of four different months are also examined in several case studies. Furthermore, sustainability analyzes are conducted considering probability of interruption of the NPP during 8 hours. According to the results, it is observed that promising solutions can be obtained thanks to the integration of the PHES in the presence of the different market types even if outages are planned.
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    The expression of Forkhead transcription factors in decidua and placenta in patients with missed abortion
    Ozbilgin, K; Kahraman, B; Turan, A; Atay, C; Vatansever, S; Inan, S; Özçakir, T
    Background: Forkhead transcription factors 3a (FOXO3a) has pleiotropic biological functions in the female reproductive tract. FOXO3a has a function in decidualization, in placental development, and also in inhibition of apoptosis. This study aims to investigate a possible role of FOXO3a in missed abortion. Materials and Methods: Decidual and placental tissue samples were obtained from the women with unwanted pregnancy as the control group and with missed abortion as the patient group. Immunohistochemistry technique was utilized to compare FOXO3a expression of the decidual cells in uterine decidual stroma and cytotrophoblast-syncytiotrophoblast cells in placental villous stroma. Immunohistochemistry was evaluated semi-quantitatively utilizing the H-score technique. Results: It was demonstrated that H-Scores of FOXO3a expression in both uterine decidual stroma were increased in the missed abortion group (255.83 +/- 12.41) than in the normal pregnancy group (133.33 +/- 17.43). It was also shown that there was no difference between non-decidual area of the endometrium of the normal pregnancy and the missed abortion group (30.33 +/- 4.32; 39.66 +/- 14.30, respectively) and placental villous stroma (13.00 +/- 1.89; 13.00 +/- 1.67, respectively). However, the immunoreactivity of cytotrophoblast and syncytiotrophoblast cells significantly increased in the missed abortion group (18.83 +/- 1.47; 322.00 +/- 6.06, respectively) than in the normal pregnancy group (11.00 +/- 1.26; 254.00 +/- 8.17, respectively) (p < 0.05). Conclusion: These data support the hypothesis that increased FOXO3a expression in missed abortion may prevent the discharge of dead fetus to maintain decidualization, prevention of oxidative stress, immunomodulation, and inhibition of apoptosis.
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    The higher heparin-binding epidermal growth factor (HB-EGF) in missed abortion
    Ozbilgin, K; Karaca, F; Turan, A; Köse, C; Vatansever, S; Ozcakir, T
    Objective: Heparin-binding epidermal growth factor (HB-EGF) has pleiotropic biological functions in the female reproductive tract. HB-EGF has a function in the menstruation cycle, implantation, decidualization, placenta development, and also inhibition of apoptosis. This study aims to investigate a possible role of HB-EGF in missed abortion. Materials and methods: Decidual and placental tissue samples were obtained from women with unwanted pregnancy as the control group and from women with missed abortions as the patient group. Immunohistochemistry was utilized to compare HB-EGF expression of fibroblast and decidual cells in uterine decidual stroma and fibroblasts and mesenchymal cells in placental villous stroma; the TUNEL technique was used to detect apoptotic cells within the decidual and placental tissues of the two groups. Results: It was demonstrated that HB-EGF expression in both uterine decidual stroma and placenta stroma was increased in the missed abortion group (142.70 +/- 12.80; 116.10 +/- 14.16, respectively), compared with the normal pregnancy group (101.60 +/- 14.18; 81.60 +/- 10.74, respectively). It was also shown that there was no difference in TUNEL (Terminal deoxynucleotide transferase dUTP Nick End Labelling) positive cells between the uterine decidual stroma (11.4 +/- 3%; 13.6 +/- 3%, respectively), placental villous stroma (13.7 +/- 3%; 15.9 +/- 3%, respectively), and cytotrophoblast-syncytiotrophoblast cells (7.3 +/- 2; 9.8 +/- 3, respectively) of the two groups. Conclusion: This data supports the hypothesis that increased HB-EGF expression in a missed abortion may prevent the discharge of the dead fetus. Copyright (C) 2014, Taiwan Association of Obstetrics & Gynecology. Published by Elsevier Taiwan LLC. All rights reserved.
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    Distribution of Furin, TNF-α, and TGF-β2 in the Endometrium of Missed Abortion and Voluntary First Trimester Termination Cases
    Ozbilgin, K; Turan, A; Kahraman, B; Atay, C; Vatansever, S; Uluer, ET; Özçakir, T
    OBJECTIVE: To identify the role of furin, TNF-alpha, and TGF-beta 2 in human missed abortion pathogenesis. STUDY DESIGN: Decidual materials were collected from patients diagnosed with a missed abortion (n=10) (missed abortion group) and from legal voluntary termination cases at <10 gestational weeks (n=10) (normal pregnancy group). Tissue samples were collected from each group by dilation and curettage under mask anesthesia. For all tissue samples, furin, TNF-alpha, and TGF-beta 2 primary antibodies were performed by immunohistochemical staining. The number of stained cells was evaluated by using the H-score technique. RESULTS: In immunohistochemical examination, the immunoreactivities of furin, TNF-alpha, and TGF-beta 2 were found to be higher in syncytiotrophoblastic cells in the missed abortion group than in the normal pregnancy group (p < 0.005). Additionally, high immunoreactivity of TNF-alpha and TGF-beta 2 molecules was established only in cytotrophoblastic cells of missed abortions (p <0.005) in examination at decidual cells of the missed abortion group; furin immunoreactivities were detected higher in the missed abortion group than in the control group, but TNF-alpha and TGF-beta 2 immunoreactivity were increased in number in the normal pregnancy group (p < 0.005). CONCLUSION: It is considered that high levels of furin and the 2 furin-related proteins (TNF-alpha and TGF-beta 2), which play important roles in proliferation, invasion, migration, differentiation, and survival of cells, may be the reason of proceeding decidualization, placentation, and prevention from abortion, in spite of terminating the fetal life.
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