Effects of Epinephrine and Cortisol on the Analgesic Activity of Metyrosine in Rats

Yavuz Albayrak,Mustafa Bahadir Saglam,Kadir Yildirim,Saliha Karatay,Beyzagul Polat,Turan Uslu,Fatih Akcay,Halis Suleyman 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.9

Some endogenous hormones (epinephrine and cortisol) can change an individual’s pain threshold. Propranolol is a non-selective β adrenergic receptor blocker which antagonises the antiinflammatory effect of non-steroidal anti-inflammatory drugs via the β1 and β2 adrenergic receptors. The roles of epinephrine and cortisol were investigated in the analgesic activity of metyrosine in rats with reduced epinephrine levels induced by metyrosine. Pain threshold measurement was performed using an analgesimeter with different doses and the single or combined usage of metyrosine, prednisolone, metyrapone and propranolol in rats. Epinephrine and corticosterone levels were measured by high-performance liquid chromatography in metyrosine-administered rats. Metyrosine reduces the epinephrine levels without affecting the corticosterone levels, thereby creating an analgesic effect. It was determined that prednisolone did not have an analgesic effect in rats with normal epinephrine levels, but its analgesic activity increased with a parallel decrease in the epinephrine levels. Similarly, the combined use of prednisolone and metyrosine provided a stronger analgesic effect than that rendered by metyrosine alone. The strongest analgesic effect, however, was observed in the group of rats with the lowest epinephrine level in whom the metyrosine + prednisolone combination was administered. The findings of this study may be useful in severe pain cases in which the available analgesics are unable to relieve the individual’s pain.

Role of Reinforcement Materials on Mechanical and Tribological Properties of PTFE Composites

Yavuz Kaplan 한국고분자학회 2020 폴리머 Vol.44 No.4

The use of polytetrafluoroethylene (PTFE) in various industrial applications under extreme operating conditions makes it very important to determine the behavior of this material. The mechanical and wear properties of PTFE can be enhanced by adding filler materials. This study focused on both the mechanical and tribological properties of PTFE and its composites with a 25 wt% addition of carbon and glass fiber (GF). Glass transition temperature (Tg), hardness, tensile, and impact tests were carried out to determine the mechanical and physical properties of PTFE. In addition, abrasive wear tests were applied to obtain wear behavior. The tensile strength values of the pure and C/GF-filled PTFE were found as 28, 16.7, and 18.6MPa, respectively. Tensile tests clearly showed that the filler materials led to a reduction of the tensile strength and elongation at break of the PTFE. Impact energy values were similarly decreased by the addition of filler materials. However, the carbon and GF additions significantly increased the abrasive wear resistance and Tg of the PTFE. Consequently, carbon and GF-filled PTFE would be a suitable candidate for use in tribological applications.

Comparison of Intravesical Hyaluronic Acid, Chondroitin Sulfate, and Combination of Hyaluronic Acid-Chondroitin Sulfate Therapies in Animal Model of Interstitial Cystitis

Yavuz Onur Danacioglu,Bulent Erol,Seyma Ozkanli,Asif Yildirim,Ramazan Gokhan Atis,Mesrur Selcuk Silay,Turhan Caskurlu 대한배뇨장애요실금학회 2021 International Neurourology Journal Vol.25 No.1

Purpose: Three intravesical treatment agents were compared in an interstitial cystitis rat model: chondroitin sulfate, hyaluronic acid, and combined hyaluronic acid-chondroitin sulfate. Methods: Thirty-five female rats were divided into 5 groups: control (group I), isotonic (group II), chondroitin sulfate (group III), hyaluronic acid (group IV), and hyaluronic acid-chondroitin sulfate (group V). Chemical cystitis was induced in all experimental groups by intravesical instillation of 1 mL of hydrogen peroxide (H2O2) for 15 minutes via the transurethral route. The treatment was administered every other day for 3 sessions 2 days after inducing chemical cystitis. Groups II, III, IV, and V received 1 mL of 0.9% NaCl, 1 mL of 0.2% sodium chondroitin sulfate, 1 mL of low-molecular-weight hyaluronic acid, and 1 mL of 2% sodium chondroitin sulfate+1.6% sodium hyaluronic acid, respectively. On day 7, the animals were sacrificed and the bladders were removed for histopathological and immunohistochemical assessments. Results: Significant between-group differences were found in vascular congestion (P=0.006). The grade of submucosal edema in groups II and IV was significantly higher than in group I (P=0.006, P=0.006, respectively). In group I, the grade of granulation tissue was lower than the other 4 groups, but no significant difference was found between the remaining groups (P=0.016). Neutrophil cell infiltration was more intense in groups II and IV than in group I (P=0.006, P=0.006, respectively). Significant differences in the leukocyte and mast cell count were detected between groups II and IV (P<0.001, P<0.001, respectively). Abnormal zonula occludens-1 and uroplakin-III immunoreactivity in group II was higher than in groups I, III, or V (P=0.002, P=0.010, respectively). Interleukin-8 expression was lower in group V than in group II (P=0.001). Conclusion: A single treatment of chondroitin sulfate and combined hyaluronic acid-chondroitin sulfate treatment demonstrated efficacy by suppressing inflammation and achieving improvements in the urothelium.

COEFFICIENT ESTIMATES FOR CERTAIN SUBCLASS FOR SPIRALLIKE FUNCTIONS DEFINED BY MEANS OF GENERALIZED ATTIYA-SRIVASTAVA OPERATOR

Yavuz, Tugba Korean Mathematical Society 2016 대한수학회논문집 Vol.31 No.4

In this article, we derive a sharp estimates for the Taylor-Maclaurin coefficients of functions in some certain subclasses of spirallike functions which are defined by generalized Srivastava-Attiya operator. Several corollaries and consequences of the main result are also considered.

A novel approach for itaconic acid extraction: Mixture of trioctylamine and tridodecylamine in different diluents

Yavuz Selim Asci,Ismail Inci 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.5

Extraction of itaconic acid has been investigated from aqueous solutions by six kind of different solutions of trioctylamine (TOA)–tridodecylamine (TDA) mixtures. Solvents have selected as dimethyl phthalate (DMP), methyl isobutyl ketone (MIBK), 2-octanone, 1-octanol, cyclohexyleacetate (CHA), and 1-decanol. Distribution and equilibrium data for design of separation equipments have been obtained as a result of batch extraction of itaconic acid. It has been calculated that distribution coefficients (D), loading factors (Z), extraction efficiency (E). The maximum removal of itaconic acid has been obtained as 98.39% with DMP and 3.14 mol L-1 initial concentration of TOA–TDA mixture.

UPPER BOUND ON THE THIRD HANKEL DETERMINANT FOR FUNCTIONS DEFINED BY RUSCHEWEYH DERIVATIVE OPERATOR

Yavuz, Tugba Korean Mathematical Society 2018 대한수학회논문집 Vol.33 No.2

Let S denote the class of analytic and univalent functions in the open unit disk $D=\{z:{\mid}z{\mid}<1\}$ with the normalization conditions f(0) = 0 and f'(0) = 1. In the present article, an upper bound for third order Hankel determinant $H_3(1)$ is obtained for a certain subclass of univalent functions generated by Ruscheweyh derivative operator.

The Relationship between Presbycusis and Mastoid Pneumatization

Yavuz Selim Pata,Yucel Akbas,Murat Unal,Meltem Nass Duce,Tugana Akbas,Deniz Micozkadioglu 연세대학교의과대학 2004 Yonsei medical journal Vol.45 No.1

Presbycusis is defined as the natural hearing loss accompanying aging, caused by degenerative changes in the inner ear. The etiology of presbycusis is uncertain. However, it would appear that a complex genetic cause is most likely. The determinants of mastoid size continue to be controversial. One of the pneumatization theories is the hereditary theory. In this study, the possible relationship between presbycusis and the extent of mastoid pneumatization was investigated. This study was carried out on 21 patients with presbycusis and 21 normal subjects of similar ages. The pneumatized volume was measured by computerized tomography. The temporal bone was scanned at 2mm thickness intervals. Exposure (kV 130, mA105). The scan plane was parallel to the orbitomeatal line and the CT images covered the entire mastoid region. The average mastoid pneumatization in presbycusis group was 6.08 ±2.52cm3 in the right ear and 6.19±2.93cm3 in the left ear. However, in the control group it was 4.69±3.17cm3 in the right ear (p=0.12) and 5.10±3.49cm3 in the left ear (p=0.28). No significant difference was found between the presbycusis patients and normal subjects in terms of the volume of mastoid pneumatization.

Transient response of functionally graded non-uniform cylindrical helical rods

Yavuz C. Cuma,Faruk Firat Calim 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.4

This paper have the objective of investigating forced vibration behaviour of axially functionally graded cylindrical helices with variable cross-section. An algorithm is developed in order to solve corresponding problems. The ordinary differential equations governing the dynamic behaviour of cylindrical helices are determined in Laplace domain by using Timoshenko beam theory. Then transfer matrix method is implemented for the solution, including shear and axial deformation effects. Obtained results are transferred to time domain using Durbin’s modified numerical inverse algorithm for Laplace transform. A benchmark problem has been solved to check the accuracy of developed algorithm then a parametric study is conducted considering the effects of material gradient index ( ), section variation parameter ( ) and number of active turns ( ). Results are compared with solutions attained from ANSYS for verification

Effects of Material Properties on Seismic Vulnerability Assessment of Unreinforced Masonry Buildings

Yavuz Yardim,Enea Mustafaraj,Erion Luga 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.5

This study investigates the seismic performance of existing unreinforced masonry buildings considering the effects of different material properties selected from design codes’ assumptions and experimental values. For this purpose, work was conducted to analyze a selection of existing buildings in Albania designed with typical methodologies of the past structural design codes. Experimental investigations were carried out on bricks and mortars extracted from the selected buildings, as well as a series of regular and irregular sized mortar specimens prepared in the laboratory for comparative evaluation purpose. In addition, diagonal compression tests were performed on two full-size (1.2 m × 1.2 m) masonry walls built in the laboratory, which were prepared based on the existing building’s construction method and material properties. Selected typical URM buildings were analyzed with commercial program CDSWin using different masonry mechanical characteristics that were obtained from experimental work in this study. The equivalent frame method (EFM) was used for the modeling of the buildings and pushover analysis was performed to obtain their seismic capacity. To evaluate the seismic response of each case, a comparison was established between the drift ratio and maximum base shear. As a result, using the code assumptions for the mechanical properties of masonry, overly conservative results were obtained. To understand better and clarify how stresses are being distributed in the walls, it is essential to perform experimental investigations to acquire the representative masonry characteristics such that a reliable structure assessment and retrofitting could be implemented.

Numerical study of ship motions and added resistance in regular incident waves of KVLCC2 model

Yavuz Hakan Ozdemir,Baris Barlas 대한조선학회 2017 International Journal of Naval Architecture and Oc Vol.9 No.2

In this study, the numerical investigation of ship motions and added resistance at constant forward velocity of KVLCC2 model is presented. Finite volume CFD code is used to calculate three dimensional, incompressible, unsteady RANS equations. Numerical computations show that reliable numerical results can be obtained in head waves. In the numerical analyses, body attached mesh method is used to simulate the ship motions. Free surface is simulated by using VOF method. The relationship between the turbulence viscosity and the velocities are obtained through the standard k ε turbulence model. The numerical results are examined in terms of ship resistance, ship motions and added resistance. The validation studies are carried out by comparing the present results obtained for the KVLCC2 hull from the literature. It is shown that, ship resistance, pitch and heave motions in regular head waves can be estimated accurately, although, added resistance can be predicted with some error.