Ramazan Demir

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We present an Approximate Dynamic Programming (ADP) approach for the multidimensional knapsack problem (MKP). We approximate the value function (a) using parametric and nonparametric methods and (b) using a base-heuristic. We propose a new heuristic which adaptively rounds the solution of the linear programming relaxation. Our computational study suggests:(More)
Vascularization within the human placenta is the result of the de novo formation of vessels derived from pluripotent precursor cells in the mesenchymal core of the villi. Vascularization of placental villi starts at around day 21 post conception (p.c.) with a four somite embryo. At this stage progenitors of haemangiogenic cells differentiate to form first(More)
Vasculogenesis and angiogenesis are two consecutive processes during blood vessel development in the human placenta. While vasculogenesis, which is the formation of first blood vessels, is achieved by differentiation of pluripotent mesenchymal cells into haemangiogenic stem cells. The subsequent step, angiogenesis, is characterized by development of new(More)
Placental villi of 5 exactly defined early human specimens ranging from day 21 post conception (p.c.) until day 42 p.c. and from an additional 43 specimens from about 5 to 40 weeks menstrual age have been analyzed ultrastructurally with regard to fetal vasculogenesis and angiogenesis. The following results were obtained: The first cells differentiating at(More)
Gamma glutamyl transferase (GGT) is a new marker for predicting myocardial infarction, stroke, cardiac death and inflammation. There is also a strong relationship between Obstructive Sleep Apnea Syndrome (OSAS) and cardiovascular disease. This study was designed to investigate the association between serum GGT levels and cardiovascular disease in patients(More)
Members of the Notch family have been detected in many developmental and cell specification processes during placental development. However, Notch protein expression in Intrauterine Growth Restriction (IUGR) and Pregnancy Induced Hypertension (PIH) is not clear. In this study we aimed to clarify the immunolocalization of Notch proteins in full-term(More)
The relationship between human sperm maturity and apoptosis is of interest because of the persistence of immature sperm in ejaculates in spite of various apoptotic processes during spermatogenesis. We assessed sperm maturity by HspA2 chaperone levels, and plasma membrane maturity by sperm binding to immobilized hyaluronic acid (HA). We also utilized(More)
Although placental development and implantation depend on the coordination of trophoblast proliferation, differentiation and invasion, little is known about the cell cycle regulators that govern the control of these events. The hypothesis that the coordinated expression of cell cycle progression and inhibition factors will determine whether cytotrophoblasts(More)
BACKGROUND Bronchiolitis obliterans organizing pneumonia (BOOP) may be classified as cryptogenic (idiopathic) and secondary. There are no clear clinical and radiological features distinguishing between idiopathic and secondary BOOP. OBJECTIVES To analyze the etiologic factors, clinical and radiological features, diagnostic approach and response to therapy(More)
INTRODUCTION Biomass (organic) fuels cause indoor air pollution when used inside dwellings. We evaluated the frequencies of chronic obstructive pulmonary disease (COPD) and chronic bronchitis (CB) among rural women using biomass fuels for heating and cooking and compared them to women living in urban areas where such fuels are not used. METHODS From(More)