Experimental and Thermal Analysis of Solar Thermoelectric System Performance Incorporated with Solar Tracker

Tahsin Atalay,Yusuf Yakut,Yavuz Köysal,Seyda Özbektaş,Hakan Bülbül,Bahattin Topaloğlu 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.2

In this study, it is aimed to determine the energy generation capability of the designed and manufactured thermoelectric system when mounted on the two-axis solar tracking system. Thus, it was possible to compare the results obtained from current study with previous study. The system used in previous study was comprised of a thermoelectric generator (TEG) for energy conversion, a linear Fresnel lens for concentrating solar rays, and a one-axis tracking system to increase the electrical and thermal efficiency of the system. In this study, a dual-axis (two-axis) tracking system was used as a tracking system to examine the change in thermal and electrical efficiency. Therefore, experimental measurements were performed again using both two-axis and one-axis solar tracking systems on 16th October 2019 and 17th October 2019, respectively, at the location which falls at 41°14′ N and 36°26′ E. Additionally, the heat transfer and electricity generation performance of TEG was theoretically analyzed using CFD model. For this purpose, a numerical model consisting TEG with heat sink was developed. It was observed that the model data obtained and the experimental data were in good agreement. The values of parameters such as temperature, solar radiation, wind speed and TEG open circuit voltage were measured instantaneously during the measurements. The maximum open circuit voltages obtained is 1.02 and 1.13 V for one-axis and dual-axis systems, respectively. The solar radiation values were measured as 464 and 472 W∕m2 , respectively when the maximum open circuit voltages value is obtained. The duration for measurements was kept about 15 min so that the average values of these parameters were used in calculations. Thus, the values of maximum output power ( P maxout) , electrical efficiency (ηe) and Seebeck coefficient ( TEG) were calculated and given in the paper.

Glutathione S-transferase T1, M1 and P1 Genetic Polymorphisms and Susceptibility to Colorectal Cancer in Turkey

Gorukmez, Ozlem,Yakut, Tahsin,Gorukmez, Orhan,Sag, Sebnem Ozemri,Topak, Ali,Sahinturk, Serdar,Kanat, Ozkan Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.8

Colorectal cancer (CRC) is reproted to be the third most common cancer worldwide and the fourth most common cause of cancer related deaths. CRC is considered to be a multifactorial disease whose risk varies due to the complex interaction between individual genetic basis and disposure to multiple endogenous factors. Glutathione S-transferases are pro-carcinogenic in CRC and are required for the conjugation between chemotherapeutics and broad spectrum xenobiotics. One hundred and eleven patients with CRC and 128 control subjects without any cancer history were enrolled in this study. Multiplex PCR was applied to determine polymorphisms for the GSTT1 and M1 genes, and PCR-RFLP was applied for the GSTP1 (Ile105Val) gene polymorphism. Values p<0.05 were defined as statistically significant. We detected a significant high correlation between predisposition for CRC and presence of the Ile/Ile genotype of the GSTP1 (IIe105Val) gene polymorphism, but we did not find a significant relationship between predisposition for CRC and GSTT1 and M1 deletion polymorphisms. In addition, we did not determine a relationship between GSTT1, M1 and P1 gene polymorphisms and any clinicopathological features of CRC. GSTT1 null/GSTM1 positive and GSTT1 null/GSTM1 positive/GSTP1 Ile/Ile genotypes were significantly higher in the patient group. Our results revealed that there is no relationship among CRC, its clinicopathologic features, and GSTT1 M1 gene polymorphisms. However, there was a significant correlation between CRC and the GSTP1 Ile/Ile genotype. Further studies with larger patient groups are required to delineate the relationships between GST gene polymorphisms and the clinicopathologic features of CRC in Turkey.

Distribution of KRAS and BRAF Mutations in Metastatic Colorectal Cancers in Turkish Patients

Gorukmez, Orhan,Yakut, Tahsin,Gorukmez, Ozlem,Sag, Sebnem Ozemri,Karkucak, Mutlu,Kanat, Ozkan Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.3

The results of this study demonstrate the potential prognostic and predictive values of KRAS and BRAF gene mutations in patients with colorectal cancer (CRC). It has been proven that KRAS and BRAF mutations are predictive biomarkers for resistance to anti-EGFR monoclonal antibody treatment in patients with metastatic CRC (mCRC). We demonstrated the distribution of KRAS (codons 12, 13 and 61) and BRAF (codon 600) gene mutations in 50 mCRCs using direct sequencing and compared the results with clinicopathological data. KRAS and BRAF mutations were identified in 15 (30%) and 1 (2%) patients, respectively. We identified KRAS mutations in codon 12, 13 and 61 in 73.3% (11/15), 20% (3/15) and 6.67% (1/15) of the positive patients, respectively. The KRAS mutation frequency was significantly higher in tumors located in the ascending colon (p=0.043). Thus, we found that approximately 1/3 of the patients with mCRC had KRAS mutations and the only clinicopathological factor related to this mutation was tumor location. Future studies with larger patient groups should yield more accurate data regarding the molecular mechanism of CRC and the association between KRAS and BRAF mutations and clinicopathological features.

GST (GSTM1, GSTT1, and GSTP1) polymorphisms in the genetic susceptibility of Turkish patients to cervical cancer

Beray Kiran,Mutlu Karkucak,Tahsin Yakut,Kemal Ozerkan,Sebnem Sag,Mehmet Ture 대한부인종양학회 2010 Journal of Gynecologic Oncology Vol.21 No.3

Objective: This work investigates the role of glutathione S-transferase M1 (GSTM1), glutathione S-transferase T1(GSTT1), and glutathione S-transferase P1 (GSTP1) enzymes and polymorphisms, which are found in phase II detoxification reactions in the development of cervical cancer. Methods: This study was conducted with 46 patients diagnosed with cervical cancer and 52 people with no cancer history. Multiplex PCR methods were used to evaluate the GSTM1 and GSTT1 gene polymorphism. However, the GSTP1 (Ile105Val) gene polymorphism was studied using a PCR-RFLP method. The patient and control groups were compared using a chi-square test with p<0.05. Results: In the patient group, statistical significance was determined for gravidity (p=0.03), parity (p=0.01), and the number of living children (p=0.01) compared to the control group. The gene frequency of GSTM1, GSTT1, and GSTP1polymorphisms was evaluated. We observed that GSTM1 and GSTT1 null genotype frequencies were 54.3% and 32.6%respectively, while GSTP1 (Ile/Val), (Ile/Ile), (Val/Val) genotype frequencies were 52%, 44%, and 4%, respectively, in the cervical cancer patients. No statistical variation was determined between the control and patient groups in terms of GSTM1, GSTT1, and GSTP1 polymorphisms (p>0.05). Conclusion: Our results demonstrate that GSTT1, GSTM1, and GSTP1 polymorphisms are not associated with cervical cancer in Turkish patients.

MMP2 Gene-735 C/T and MMP9 gene -1562 C/T Polymorphisms in JAK2V617F Positive Myeloproliferative Disorders

Sag, Sebnem Ozemri,Gorukmez, Ozlem,Ture, Mehmet,Gorukmez, Orhan,Topak, Ali,Sahinturk, Serdar,Ocakoglu, Gokhan,Gulten, Tuna,Ali, Ridvan,Yakut, Tahsin Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.2

Background: Myeloproliferative disorders (MPDs) are clonal hematologic malignancies originating at the level of the pluripotent hematopoietic stem cell. Matrix metalloproteases (MMPs) are proteolytic enzymes that contribute to all stages of malignancy progression. Genetic variants in the MMP genes may influence the biological function of these enzymes and change their role in carcinogenesis and progression. To our knowledge, this is the first investigation of associations between the -735 C/T and -1562 C/T polymorphisms in the MMP2 and MMP9 genes, respectively, and the risk of essential thrombocytosis (ET), and polycythemia vera (PV). Materials and Methods: The case-control study included JAK2V617F mutation positive 102 ET and PV patients and 111 controls. Polymorphisms were determined by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and electrophoresis. Results: No statistically significant differences were detected between patient (ET+PV) and control groups regarding genotype distribution for MMP2 gene-735 C/T and MMP9 gene -1562 C/T polymorphisms and C/T allele frequency (p>0.050). Statistically borderline significance was observed between PV and control groups regarding genotype distribution for the MMP9 gene -1562 C/T polymorphism (p=0.050, OR=2.26, 95%Cl=0.99-5.16). Conclusions: Consequently this study supported that CC genotype of MMP9 gene -1562 C/T polymorphism may be related with PV even if with borderline significance.