Lycopene Partially Reverses Symptoms of Diabetes in Rats with Streptozotocin-Induced Diabetes

Aysegul Bayramoglu,Gokhan Bayramoglu,Hakan Senturk 한국식품영양과학회 2013 Journal of medicinal food Vol.16 No.2

In the present study, we describe the effects of lycopene on the symptoms of streptozotocin (STZ)–induced diabetes in rats. Lycopene at the dose of 2.5 mg/kg body weight (bw) per day was orally administered to STZ-induced diabetic rats for a period of 7 days after onset of diabetes. At the same time, food–water intake and body weight change were recorded daily. Upon sacrifice, biochemical parameters, such as the serum glucose, insulin, total cholesterol (TC), triglyceride (TG), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), were measured in all experimental groups. Administration of lycopene at the dose of 2.5 mg/kg bw per day significantly reduced serum glucose, TC, TG, ALT, and AST levels, and increased serum insulin levels, but there were no improvements in food–water intake and body weight change parameters in lycopene-treated diabetic rats. The results suggest that orally administrated lycopene exhibits a potent hypoglycemic effect in STZ-induced diabetic rats and that lycopene may be useful for the management of diabetes mellitus.

Reliability analysis of tested steel I-beams with web openings

Bayramoglu, Guliz Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.41 No.5

This paper presents a reliability analysis of steel I-beams with rectangular web openings, based on a combination of the common probabilistic reliability methods, such as RSM, FORM and SORM and using data obtained from experimental tests performed at the Istanbul Technical University. A procedure is proposed to obtain the optimum design load that can be applied to this type of structural members, by taking into account specified target values of reliability indices for ultimate and serviceability limit states. The goal of the paper is to present an algorithm to obtain more realistic and economical design of beams and to demonstrate that it can be applied efficiently to steel I-beams with web openings. Finally, a sensitivity analysis is performed allowing to ranking the random variables according to their importance in the reliability analysis.

Seismic performance evaluation and retrofitting with viscous fluid dampers of an existing bridge in Istanbul

Bayramoglu, Guliz,Ozgen, Alpay,Altinok, Enver Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.4

In this paper, seismic performance of Kozyatagi Bridge is evaluated by employing nonlinear elasto-plastic dynamic analysis and the deformation-based performance. The time-history records of the 1999 Izmit, 1971 San Fernando and 1989 Loma Prieta earthquakes are modified by adopting a probability of exceedance of 2% in 50 years corresponding to the return period of 2475 years. The analysis is carried out for three different bearing cases which are movable bearings, restrained bearings, and movable bearings with viscous fluid dampers in the radial direction. The analysis results show that the bridge can be retrofitted with viscous fluid dampers. In this case the reinforced concrete piers need not be strengthened by any jacketing techniques in order to preserve the original architectural appearance of the bridge. The retrofitting design of the bridge with viscous fluid dampers is also presented in detail.

Azo Dye Removal Using Free and Immobilized Fungal Biomasses: Isotherms, Kinetics and Thermodynamic Studies

Gulay Bayramoglu,Meltem Yilmaz 한국섬유공학회 2018 Fibers and polymers Vol.19 No.4

In this study, Lentinus concinnus biomass was immobilized in polyvinyl alcohol/polyethyleneoxide hydrogels (PVA/PEO; referred as composite biomass) and used for removal of Reactive Yellow 86 dye (RY-86) from aqueous solution using free fungal biomass as a control system. The free fungal and composite fungal biomasses were characterized using ATR-FTIR, SEM and analytical methods. FTIR studies of the adsorbent preparations show that carboxylate, hydroxyl and amine groups should be involved in adsorption of the RY-86 dye. The adsorption of RY-86 dye on these adsorbents increased as the initial concentration of RY-86 dye in the medium increased up to 200 mg/l. The maximum RY-86 dye adsorption for the free fungal and composite fungal biomasses, was obtained as 190.2 and 87.6, respectively, using 200 mg/l initial dye concentration, at 25 oC, and at pH 5.0 with 2.0 h contact. The equilibrium data were well described with the Freundlich and Temkin isotherm models. The adsorption of RY-86 dye was fitted best by the pseudo second-order kinetic model. Thermodynamic parameters (ΔGo, ΔHo, and ΔSo) showed that RY-86 dye adsorption on both adsorbents were spontaneous process.

Preparation and Characterization of Poly(hydroxyethyl methacrylate-co-poly(ethyl-eneglycol-methacrylate)/Hydroxypropyl-chitosan) Hydrogel Films:Adhesion of Rat Mesenchymal Stem Cells

Gulay Bayramoglu,K. Can Akcall,Sinan Gultekin,Erman Bengu,M. Yakup Arica 한국고분자학회 2011 Macromolecular Research Vol.19 No.4

This study examined the effects of the surface properties of the materials, such as the hydroxyl, methyl and amino groups, on rat bone marrow derived Mesenchymal Stem Cell (MSC) seeding. A series of hydrogels were prepared in film form using 2-hydroxyethyl methacrylate (pHEMA), poly(ethyleneglycol) methacrylate (PEG-MA),and/or hydroxypropyl-chitosan (HPC). The physicochemical properties of these hydrogel films, such as water content, functional groups, contact angle, surface energy and thermal properties were affected by the composition of the materials. The ability of the MSCs to form colonies, as well as their viability on these materials were also analyzed. The water content of the hydrogel films increased with increasing PEG-MA and HPC ratio in the hydrogel. Contact angle measurements of the surface of the hydrogel films demonstrated that all the materials gave rise to a significantly hydrophilic surface compared to pure pHEMA. The blood protein interactions and platelet adhesion were reduced significantly on the surface of the materials upon the incorporation of PEG-MA compared to the control pure pHEMA and vice versa for HPC. The ability of the MSCs to adhere and form colonies on these materials was also analyzed. The results showed that these materials are suitable candidates to isolate and expand MSCs.

Reliability analysis of tested steel I-beams with web openings

Guliz Bayramoglu 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.41 No.5

This paper presents a reliability analysis of steel I-beams with rectangular web openings, based on a combination of the common probabilistic reliability methods, such as RSM, FORM and SORM and using data obtained from experimental tests performed at the Istanbul Technical University. A procedure is proposed to obtain the optimum design load that can be applied to this type of structural members, by taking into account specified target values of reliability indices for ultimate and serviceability limit states. The goal of the paper is to present an algorithm to obtain more realistic and economical design of beams and to demonstrate that it can be applied efficiently to steel I-beams with web openings. Finally, a sensitivity analysis is performed allowing to ranking the random variables according to their importance in the reliability analysis.

Cyclic-carbonate functionalized polymer brushes on polymeric microspheres: Immobilized laccase for degradation of endocrine disturbing compounds

Gulay Bayramoglu,Bunyamin Karagoz,M. Yakup Arica 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.60 No.-

A novel support material containing cyclic carbonate group for facile enzyme immobilization was synthesized from [poly(styrene-co-divinylbenzene)-graft-poly(glycidyl methacrylate)] “[PS-co-DVB-g-P(GMA)]” microsphere under carbon dioxide atmosphere. It was named as (poly(styrene-co-divinylbenzene)-graft-poly(cyclic-carbonate methacrylate)] “[PS-co-DVB-g-P(CCMA)]” microsphere. Laccase was covalently immobilized using the microspheres carrying cyclic epoxy and cyclic carbonate groups. The amount of enzyme loading on the cyclic carbonate groups of the microspheres was 47.8 mg/g. The immobilized enzyme was used for degradation of Bisphenol A, and Congo Red dye in packed bed reactor. The immobilized laccase preserved its initial activity about 67.5% and 93.0% for degradation of Bisphenol A and Conge Red, respectively.

Adsorption of Congo Red dye by native amine and carboxyl modified biomass of Funalia trogii: Isotherms, kinetics and thermodynamics mechanisms

Gulay Bayramoglu,Mehmet Yakup Arica 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.6

Native, iminodiacetic acid and triethylenetetraamine modified biomasses of Funalia trogii were used for removal of Congo Red dye (CRD) from aqueous medium. The native and modified fungal biomasses were characterized using ATR-FTIR, Zeta potential, contact angle studies and analytical methods. FTIR studies of the native and chemically modified adsorbent preparations show that amine, carboxyl and hydroxyl groups are involved in the adsorption of the model dye (i.e., Congo Red). The maximum adsorption of the CRD on the native, carboxyl and amine groups modified fungal biomasses was obtained at pH 5.0. The amount of adsorbed dye on the adsorbent samples increased as the initial concentration of CRD in the solution increased to 200mg/L. The adsorption capacities of native, carboxyl groups and amine modified fungal preparations were 90.4, 153.6 and 193.7mg/g dry adsorbents, respectively. The data was fitted well with the Langmuir isotherm model, and followed the pseudo-second-order equations. Thermodynamic parameters (Go, Ho and So) were also calculated. The results showed that triethylenetetraamine (TETA) modified biomass of F. trogii presented an excellent dye removal performance and can be used in various environmental applications such as various micro-pollutants removal from aqueous medium.

Seismic performance evaluation and retrofitting with viscous fluid dampers of an existing bridge in Istanbul

Guliz Bayramoglu,Alpay Ozgen,Enver Altınok 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.4

In this paper, seismic performance of Kozyatagi Bridge is evaluated by employing nonlinear elasto-plastic dynamic analysis and the deformation-based performance. The time-history records of the 1999 Izmit, 1971 San Fernando and 1989 Loma Prieta earthquakes are modified by adopting a probability of exceedance of 2% in 50 years corresponding to the return period of 2475 years. The analysis is carried out for three different bearing cases which are movable bearings, restrained bearings, and movable bearings with viscous fluid dampers in the radial direction. The analysis results show that the bridge can be retrofitted with viscous fluid dampers. In this case the reinforced concrete piers need not be strengthened by any jacketing techniques in order to preserve the original architectural appearance of the bridge. The retrofitting design of the bridge with viscous fluid dampers is also presented in detail.

Numerical analysis of elasto-plastic adhesively single step lap joints with cohesive zone models and its experimental verification

Simay Bayramoglu,Salih Akpinar,Ahmet Çalık 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.2

Adhesive bonding method is used as an alternative to mechanical bonding methods, and it is frequently used in automotive, space and aviation industries. In the present study; the displacement and failure load capacity characteristics of single step lap joint was measured experimentally and compared with results of finite element (FE) analysis. In addition, the change in the length and the thickness of the material and adhesive in this joint type, stresses on the adhesive was examined by numerical analysis that have affected. Also, the effects of overlap length and material thickness on the stresses in adhesive were examined with numerical analysis for the single step lap joint. AA2024-T3 aluminum alloy adhered material and double component DP460 structural adhesive was used as adhesives in the single step lap joint. In the numerical analysis of this joint type, two different material models including multilinear isotropic hardening (MISO) and cohesive zone model (CZM) were used in the adhesive layer. During the experimental tests, two cameras were used to measure the displacements and crack propagations. As a result, the data obtained from the numerical analysis were compared to the experimental data of the single step lap joint type, the use of CZM in the adhesive region was found to be very important in terms of compliance. Thus, the difference between CZM and MISO results in terms of damage load in adhesive is 7 %, while this difference is 32 % in terms of displacement. Also, it has a great importance to get the displacement data via a video extensometer for the compatibility of FE and experimental analyses. Another result obtained from the study is that changing the material thickness, the adhesive thickness and the overlap length in the joint, changes the stress concentrations and shear stresses at the ends of the overlap area.