Cilt 02, Sayı 1 (2012)

Bilevel stochastic transportation problem with exponentially distributed demand

Sun, 01 Jan 2012 00:00:00 GMT

Bilevel stochastic transportation problem with exponentially distributed demand Günay Akdemir, Hande; Tiryaki, Fatma In this paper, we consider a bilevel stochastic transportation problem (BSTP) which is a two level hierarchical program to determine optimal transportation plan for a single product assuming that customers’ demands for the product are stochastic, in particular, exponentially distributed random variables. In our model, we suppose that the leader and the follower operate two separate groups of plants in a decentralized firm. The leader, who moves first, determines quantities shipped to customers, and then, the follower decides his own quantities rationally. There are holding and shortage costs at the customer zones. The leader’s objective is to minimize the sum of corresponding total transportation costs and the total expected holding cost. Holding costs can be negative which implies that the leader can sell excess quantities at some prices. Similarly, the follower’s objective is to minimize the sum of the corresponding total transportation costs and the total expected shortage cost. Our proposed model is transformed into a single level nonlinear programming by using its Karush-Kuhn-Tucker (KKT) conditions, and then, it is applied with a branch and bound algorithm to obtain noncooperative solutions. A small numerical example is also given to illustrate our model. Keywords: Bilevel programming, stochastic programming, stochastic transportation problem, exponentially distributed demand

The antioxidant effect of boric acid and CoQ10 on pulmonary fibrosis in bleomycin induced rats

Sun, 01 Jan 2012 00:00:00 GMT

The antioxidant effect of boric acid and CoQ10 on pulmonary fibrosis in bleomycin induced rats Çelikezen, Fatih Çağlar; Oto, Gökhan; Özdemir, Hülya; Kömüroğlu, Ufuk; Yörük, İbrahim; Demir, Halit; Çilingir Yeltekin, Aslı The purpose of this study is to investigate the antioxidant effects boric acid and CoQ10 has on pulmonary fibrosis in bleomycin induced rats. 32 wistar albino male rats were used in this study. The rats were categorised in four groups; a control group (only given normal saline), a bleomycin (BLM) group, a BLM + boric acid group, and a BLM + boric acid + CoQ10. The study period was adjusted to 30 days. Retinol, vitamin E, vitamin D, catalase, carbonic anhydrase, glucose, total protein, albumin, globulin, and total bilirubin levels were measured at the end of the study. There was a significant increase in the vitamin E levels of all groups (p<0.05). There was a statistically significant increase in the glucose level of all groups (P<0.001). There were significant decreases in albumin and total protein levels of all groups. While the significance level of the decrease in the albumin level was p<0.001, the significance level of the decrease in the total protein level was p<0.05. There was no significant difference in other biochemical parameters.

Purification and characterization of polyphenol oxidase enzyme from Iğdır apricot (Prunus armeniaca L.)

Sun, 01 Jan 2012 00:00:00 GMT

Purification and characterization of polyphenol oxidase enzyme from Iğdır apricot (Prunus armeniaca L.) Demir, Halit; Çimen, Çilem; Çelikezen, Fatih Çağlar In this study, polyphenol oxidase enzyme obtained from Iğdır apricot was purified with method of affinity chromatography. The apricot cultivar “şalak” was provided from Iğdır region. To purify polyphenol oxidase enzyme, obtained from Iğdır apricot, phosphate buffer at 7.3 pH was used and the homogenate was prepared. The homogenate was applied to activate sepharose 4B-tyrosine-paminobenzoic acid affinity column. For quantitative protein analyses, fractions obtained from column, and showing activity, was performed at 595 nm with coomassie blue method. In addition, optimum pH of enzyme, its optimum temperature, ionic strength effect and inhibition kinetics of some drugs and chemicals on enzyme were investigated. Optimum pH of enzyme and its optimum temperature were found to be 6 and 30oC, respectively. Furthermore, the study carried out on the ionic strength revealed that the highest activity was observed in concentration of 0.16 M (NH4)2SO4.

The evaluation of obesity through blood parametres

Sun, 01 Jan 2012 00:00:00 GMT

The evaluation of obesity through blood parametres Battaloğlu İnanç, Betül Obesity and dyslipidemia are increasing problems in many countries and related the multiple cardiovascular risk factors. The purpose of this study was to determine the association between some simple anthropometric measurements and lipid parameters. In all patients, age, gender, weight, and height were recorded. Body mass index (BMI) calculated. Plasma leptin, total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL), impairment fasting glucose (IFG) and CRP ( C-Reactive Protein Test) were recorded and compared. There was a significant correlation in adult obese patient group between BMI, TC, VLDL (p<0.001); IFG, LDL, TG, and serum leptin (p<0.05) level. CRP and HDL were higher but not statistical significant.