Synthesis of Poly(N-methylol Methacrylamide/Vinyl Sulfonic Acid) Hydrogels for Heavy Metal Ion Removal

Yakar, Arzu Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.10

In this study, poly(N-methylol methacrylamide) (NMMAAm) and poly(N-methylol methacrylamide/vinyl sulphonic acid) (NMMAAm-VSA) hydrogels were synthesized by $^{60}Co-{\gamma}$ ray irradiation at an ambient temperature. The graphs belonging to the gelation percent- percent-dose and swelling curves were drawn by using data which were obtained from water and different pH solutions. Characterization of hydrogels was performed by FTIR and DSC-TGA analysis. Heavy metal ion ($Ni^{2+}$, $Co^{2+}$) removal capacities of hydrogels were investigated in aqueous solutions, which had different concentrations (100-1500 mg/L). In metal ion removal studies, pH value of aqueous medium was kept constant at 5.0. Maximum metal ion removal values were obtained for NMMAAm-VSA (1:3 mole ratio) hydrogels. Metal ion removal capacities of NMMAAm-VSA (1:3 mole ratio) hydrogels were found as 82 mg/g and 98 mg/g for $Ni^{2+}$ and $Co^{2+}$ ions, respectively.

Reliability and Validity of Turkish Version of the Caregiver Quality of Life Index Cancer Scale

Yakar, Hatice Karabuga,Pinar, Rukiye Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.7

Background: Measuring effects of cancer on family caregivers is important to develop methods which can improve their quality of life (QOL). Nevertheless, up to now, only a few tools have been developed to be used in this group. Among those, the Caregiver Quality of Life Index-Cancer Scale (CQOLC) has met minimum psychometric criteria in different populations in spite of conflicting results. The present study was conducted to evaluate reliability and validity of CQOLC among Turkish cancer family caregivers. Materials and Methods: The CQOLC was administered to 120 caregivers, along with Beck Depression Inventory (BDI), Medical Outcomes Study MOS 36- Item Short Form Health Survey (SF-36), State-Trait Anxiety Inventory (STAI), and Multidimensional Scale of Perceived Social Support (MSPSS). Internal consistency and test-retest stability were used to investigate reliability. Construct validity was examined by using known group method, convergent, and divergent validity. For the known group method, we hypothesized that CQOLC scores would differ between depressed and non-depressed subjects. We investigated convergent validity by correlating scores for CQOLC with scores for other similar measures including SF-36 and STAI. The MSPSS was completed at the same time as CQOLC to provide divergent validity. Results: The values for internal consistency and test-retest correlation were 0.88 and 0.96, respectively. The CQOLC discriminated those who were depressed from those who were not. Convergent validity supported strong correlations between CQOLC scores and two main component scores (PCS, MCS) in SF-36 although there was a weak correlation between CQOLC and STAI scores. Regarding divergent validity, the correlation between CQOLC and MSPSS was in the low range, as expected. Conclusions: The Turkish CQOLC is a reliable and valid tool and it can be utilized to determine QOL of family caregivers.

A Highway Alignment Determination Model Incorporating GIS and Multi-Criteria Decision Making

Ferit Yakar,Fazil Celik 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.6

Construction, repair and maintenance costs of a highway as well as its operation performance and environmental-social effects are mostly depend on its alignment. Therefore, the most important step in the highway planning activity is the alignment determination step. In this study; a 3 stage model incorporating Multi-Criteria Decision Making (MCDM) and Geographical Information Systems (GIS) is developed for highway alignment determination process. In the model; many criteria are handled simultaneously at the beginning of the project according to a concrete procedure with the existence of spatial data, and thus, many drawbacks of existing alignment determination process are eliminated. Fuzzy functions were used in the standardization of criteria maps. Analytic Hierarchy Process (AHP) was used in the determination of criteria weights. Weighted Lineer Combination method was used for the combination of criteria maps. Developed model was tested in a highway project in Tokat, Turkey. IDRISI software was used in the case study for the application of the model. It is seen that use of three stages in the process makes it easy; to take constraints into evaluation, to create alignment alternatives with different viewpoints and to make selection between alternatives with different viewpoints.

Synthesis of Poly(N-methylol Methacrylamide/Vinyl Sulfonic Acid) Hydrogels for Heavy Metal Ion Removal

Arzu Yakar 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.10

In this study, poly(N-methylol methacrylamide) (NMMAAm) and poly(N-methylol methacrylamide/vinyl sulphonic acid) (NMMAAm-VSA) hydrogels were synthesized by 60Co-γ ray irradiation at an ambient temperature. The graphs belonging to the gelation percent- percent-dose and swelling curves were drawn by using data which were obtained from water and different pH solutions. Characterization of hydrogels was performed by FTIR and DSC-TGA analysis. Heavy metal ion (Ni2+, Co2+) removal capacities of hydrogels were investigated in aqueous solutions, which had different concentrations (100-1500 mg/L). In metal ion removal studies, pH value of aqueous medium was kept constant at 5.0. Maximum metal ion removal values were obtained for NMMAAm-VSA (1:3 mole ratio) hydrogels. Metal ion removal capacities of NMMAAm- VSA (1:3 mole ratio) hydrogels were found as 82 mg/g and 98 mg/g for Ni2+ and Co2+ ions, respectively.

Endovascular occlusion of giant serpentine aneurysm: A case report and literature review

Civlan Serkan,Yakar Fatih,Coskun Mehmet Erdal,Sato Kenichi 대한뇌혈관외과학회 2022 Journal of Cerebrovascular and Endovascular Neuros Vol.24 No.1

Giant serpentine aneurysms (GSAs) are a rare subgroup of intracranial aneurysms. Separate inflow and outflow flow due to intraluminal thrombosis is the most distinguishing feature of GSAs. In treating these lesions, surgical clipping and ligation were the main treatments in the past, but bypass for revascularisation and endovascular therapies (EVTs) for deconstructive purposes are more prominent today. A 51-years-old male patient presented with headache and mild right hemiparesis. He had a GSA arising from the left fetal type posterior cerebral artery (fPCA) that was out of follow-up for six years. Radiological images revealed midline shifting and mesencephalon compression. We performed endovascular parent artery coil occlusion. The symptoms of the patient improved at the first-month follow-up. Even if there is a mass effect in GSAs, deconstructive EVT is a safe and feasible method for managing these lesions.

Investigation of the performance of a thermoelectric generator system utilizing the thermal energy of air compressed in a compressor

Gürcan Ali,Yakar Gülay 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.80 No.6

The present study includes a numerical analysis on the electrical power output of a thermoelectric generator system placed between a compressor and the intercooler of a turbocharged tractor. Although current literature already includes reports on thermal energy of exhaust gases used by thermoelectric generators in automobiles, this study is oriented on the utility of the thermal energy of the compressed outlet air from the compressor by the thermoelectric generators. This is the uniquness of the present study. Numerical results showed that the highest and the lowest performances occurred at outdoor temperatures of 268 K and 303 K, respectively. From a single thermoelectric module, while a 1.23 W power output was obtained at outdoor temperature of 268 K, a 0.7 W power output was obtained at 303 K. The thermoelectric generator system used in this study consisted of 28 thermoelectric generator modules. The power output generated by this system can be used for any electrically powered devices on a tractor, such as a tractor refrigerator with a thermoelectric cooler whose power requirement can be easily satisfied by using the thermoelectric generator system. In a turbocharged tractor with a thermoelectric generator, the temperature of the air entering into the intercooler for a single thermoelectric generator module was decreased by 1.6% at an outdoor temperature of 268 K in comparison with the one without the thermoelectric generator.

Evaluation of Portal Venous Velocity with Doppler Ultrasound in Patients with Nonalcoholic Fatty Liver Disease

Serife Ulusan,Tolga Yakar,Zafer Koc 대한영상의학회 2011 Korean Journal of Radiology Vol.12 No.4

Purpose: We examined the relationship between portal venous velocity and hepatic-abdominal fat in patients with nonalcoholic fatty liver disease (NAFLD), using spectral Doppler ultrasonography (US) and magnetic resonance imaging (MRI). Materials and Methods: In this prospective study, 35 patients with NAFLD and 29 normal healthy adults (control group) underwent portal Doppler US. The severity of hepatic steatosis in patients with NAFLD was assessed by MRI through chemical shift imaging, using a modification of the Dixon method. Abdominal (intra-abdominal and subcutaneous) fat was measured by MRI. Results: The difference in portal venous velocity between the patients with NAFLD and the control group was significant (p < 0.0001). There was no correlation between the degree of abdominal or hepatic fat and portal venous velocity (p > 0.05). There were strong correlations between the hepatic fat fraction and subcutaneous adiposity (p < 0.0001), intraperitoneal fat accumulation (p = 0.017), and retroperitoneal fat accumulation (p < 0.0001). Conclusion: Our findings suggest that patients with NAFLD have lower portal venous velocities than normal healthy subjects. Purpose: We examined the relationship between portal venous velocity and hepatic-abdominal fat in patients with nonalcoholic fatty liver disease (NAFLD), using spectral Doppler ultrasonography (US) and magnetic resonance imaging (MRI). Materials and Methods: In this prospective study, 35 patients with NAFLD and 29 normal healthy adults (control group) underwent portal Doppler US. The severity of hepatic steatosis in patients with NAFLD was assessed by MRI through chemical shift imaging, using a modification of the Dixon method. Abdominal (intra-abdominal and subcutaneous) fat was measured by MRI. Results: The difference in portal venous velocity between the patients with NAFLD and the control group was significant (p < 0.0001). There was no correlation between the degree of abdominal or hepatic fat and portal venous velocity (p > 0.05). There were strong correlations between the hepatic fat fraction and subcutaneous adiposity (p < 0.0001), intraperitoneal fat accumulation (p = 0.017), and retroperitoneal fat accumulation (p < 0.0001). Conclusion: Our findings suggest that patients with NAFLD have lower portal venous velocities than normal healthy subjects.

a systematic review and meta-analysis of observational studies

Mehmet Onur Kaya,Esra Pamukç,u,Burkay Yakar 한국역학회 2021 Epidemiology and Health Vol.43 No.-

OBJECTIVES: Although vaccination has started, coronavirus disease 2019 (COVID-19) poses a continuing threat to public health. Therefore, in addition to vaccination, the use of supplements to support the immune system may be important. The purpose of this study was to synthesize evidence on the possible effect of low serum vitamin D levels (25[OH]D<20 ng/mL or 50 nmol/L) on COVID-19 infection and outcomes. METHODS: We searched Google Scholar, PubMed, Scopus, Web of Science, and ScienceDirect without any language restrictions for articles published between January 1 and December 15, 2020. We performed 3 meta-analyses (called vitamin D and COVID-19 infection meta-analysis [D-CIMA], vitamin D and COVID-19 severity meta-analysis [D-CSMA], and vitamin D and COV ID-19 mortality meta-analysis [D-CMMA] for COVID-19 infection, severity, and mortality, respectively) to combine odds ratio values according to laboratory measurement units for vitamin D and the measured serum 25(OH)D level. RESULTS: Twenty-one eligible studies were found to be relevant to the relationship between vitamin D and COVID-19 infection/outcomes (n=205,869). The D-CIMA meta-analysis showed that individuals with low serum vitamin D levels were 1.64 times (95% confidence interval [CI], 1.32 to 2.04; p<0.001) more likely to contract COVID-19. The D-CSMA meta-analysis showed that people with serum 25(OH)D levels below 20 ng/mL or 50 nmol/L were 2.42 times (95% CI, 1.13 to 5.18; p=0.022) more likely to have severe COVID-19. The D-CMMA meta-analysis showed that low vitamin D levels had no effect on COVID-19 mortality (OR, 1.64; 95% CI, 0.53 to 5.06, p=0.390). CONCLUSIONS: According to our results, vitamin D deficiency may increase the risk of COVID-19 infection and the likelihood of severe disease. Therefore, we recommend vitamin D supplementation to prevent COVID-19 and its negative outcomes.

The role of vitamin D deficiency on COVID-19: a systematic review and meta-analysis of observational studies

Kaya Mehmet Onur,Pamukçu Esra,Yakar Burkay 한국역학회 2021 Epidemiology and Health Vol.43 No.-

OBJECTIVES: Although vaccination has started, coronavirus disease 2019 (COVID-19) poses a continuing threat to public health. Therefore, in addition to vaccination, the use of supplements to support the immune system may be important. The purpose of this study was to synthesize evidence on the possible effect of low serum vitamin D levels (25[OH]D< 20 ng/mL or 50 nmol/L) on COVID-19 infection and outcomes. METHODS: We searched Google Scholar, PubMed, Scopus, Web of Science, and ScienceDirect without any language restrictions for articles published between January 1 and December 15, 2020. We performed 3 meta-analyses (called vitamin D and COVID-19 infection meta-analysis [D-CIMA], vitamin D and COVID-19 severity meta-analysis [D-CSMA], and vitamin D and COV ID-19 mortality meta-analysis [D-CMMA] for COVID-19 infection, severity, and mortality, respectively) to combine odds ratio values according to laboratory measurement units for vitamin D and the measured serum 25(OH)D level. RESULTS: Twenty-one eligible studies were found to be relevant to the relationship between vitamin D and COVID-19 infection/outcomes (n= 205,869). The D-CIMA meta-analysis showed that individuals with low serum vitamin D levels were 1.64 times (95% confidence interval [CI], 1.32 to 2.04; p< 0.001) more likely to contract COVID-19. The D-CSMA meta-analysis showed that people with serum 25(OH)D levels below 20 ng/mL or 50 nmol/L were 2.42 times (95% CI, 1.13 to 5.18; p= 0.022) more likely to have severe COVID-19. The D-CMMA meta-analysis showed that low vitamin D levels had no effect on COVID-19 mortality (OR, 1.64; 95% CI, 0.53 to 5.06, p= 0.390). CONCLUSIONS: According to our results, vitamin D deficiency may increase the risk of COVID-19 infection and the likelihood of severe disease. Therefore, we recommend vitamin D supplementation to prevent COVID-19 and its negative outcomes.

The performance of Nafion1424 in the membrane electrolysis of borax solution

Abdullah Zahid Turan,Tahsin Bahar,I. Ersan Kalafatoglu,Iffet Yakar Elbeyli 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.3

The aim of the study was to investigate the performance of a monolayer cation exchange membrane (Nafion1424) in the membrane electrolysis of aqueous borax solution. Membrane cell was basically composed of a hydrogen evolving cathode, oxygen evolving anode and Nafion1424. Boric acid solution,sodium hydroxide solution, oxygen and hydrogen gases were produced by continuous electrolysis process. The effects of different catholyte concentrations (10, 20, 30 and 35% NaOH) on the current efficiency were investigated. The electrical power consumption per ton for the production of sodium hydroxide (100%) and boric acid were calculated and the qualities of boric acid products were determined.