The preparation and applications of novel phosphazene crosslinked thermo and pH responsive hydrogels

Hava Ozay,Ozdem Sahin,Omer Kaan Koc,Ozgur Ozay 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.43 No.-

In this study, we synthesized a novel phosphazene compound hexakis[4-(acrylamido)phenoxy]cyclotriphosphazene (HAAP) as crosslinker. The structure of compound was identified usingspectroscopic techniques. Then, HAAP was used as crosslinker for the synthesis of thermo and pHresponsive p(NIPAM-co-VI) hydrogels. The structure and swelling behavior of hydrogel was investigated. Then, HAAP-crosslinked p(NIPAM-co-VI) hydrogels were used for in vitro release of Rhodamine 6G asdrug release matrix. Additionally, HAAP-crosslinked p(NIPAM-co-VI) hydrogels were used as supportmaterial for the preparation of cobalt metal catalysts. The prepared HAAP-crosslinked p(NIPAM-co-VI)-Co composite catalyst was used as catalyst for the reduction reaction of 4-nitrophenol.

Microstructural and wear properties of the Al-B 4 C composite coating produced by hot-press sintering on AA-2024 alloy

C. Ozay,H. Ballikaya,F. Dagdelen,O. E. Karlidag 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7

In this study, the surface of an AA-2024 alloy was covered with reinforced composite coating using hotpress sintering method. Al and B 4 C powders were synthesized through mechanical alloying technique and coated on the AA-2024 substrate at different rates. The microstructure of the intermediate transition region formed between the substrate (AA-2024 Al alloy) and the coating layer (Al/B 4 C MMCs), the microstructure of the Al/B 4 C metal matrix composites (MMCs) coating, the microhardness, and the adhesive wear resistance of the Al/B 4 C MMCs coating layer were investigated. It was observed that B 4 C powders homogeneously dispersed in the microstructure of the Al/B 4 C MMCs coating layer, moreover, the Al matrix and B 4 C reinforcement particles were bonded without a gap. It was also determined that an interface bonding occurred between Al/B 4 C MMCs coating layer and the AA-2024 substrate. Accordingly, it was determined that with the increase of B 4 C reinforcement particle ratio, the hardness of the coating layer, and the wear resistance increased.

Measuring urinary 8-hydroxy-2′-deoxyguanosine and malondialdehyde levels in women with overactive bladder

Eda Dokumacioglu,Ozay Demiray,Ali Dokumacioglu,Arzu Sahin,Tugba Mazlum Sen,Soner Cankaya 대한비뇨의학회 2018 Investigative and Clinical Urology Vol.59 No.4

Purpose: In this study, we aimed to explain the role of oxidative stress in women with overactive bladder (OAB) by investigating the levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, and malondialdehyde (MDA), an indicator of lipid peroxidation. Materials and Methods: A total of 90 women were included in the study: 45 female patients diagnosed with OAB at Hopa State Hospital Urology Polyclinic and 45 healthy women without any metabolic or neurologic disease. Levels of MDA and 8-OHdG were measured in 24-hour urine samples for all subjects. Results: Urinary levels of MDA and 8-OHdG were significantly higher in the OAB group than in the control group (p<0.001). A significant positive correlation (p<0.001) was found between the measurements of 8-OHdG and MDA. Conclusions: Oxidative stress may be important in the pathophysiology of OAB, because levels of 8-OHdG and MDA are increased. Increased levels of 8-OHdG may be due to damaged nuclear and mitochondrial DNA as a result of oxidative attacks caused by free radicals. Nevertheless, further randomized and prospective studies with larger patient populations are needed.

Bilateral Congenital Anophthalmos and Agenesis of the Optic Pathways

Mustafa Aktekin,Ozay Oz,Muaffak Refick Saygili,Zeliha Kurtoglu 연세대학교의과대학 2005 Yonsei medical journal Vol.46 No.2

This report presents a rare example of a bilateral congenital anophthalmos and an agenesis of the optic pathways. The MR imaging studies revealed that the eyeballs, optic nerves, optic chiasm, optic tracts and optic radiation were absent. The chromosomal examination was normal. Mild mental retardation was also observed. Apart from the rarity of the anophthalmos and the total absence of the optic pathways, no etiologic reason for this pathology could be detected, which makes this case more significant.

Minimization of differential column shortening and sequential analysis of RC 3D-frames using ANN

Njomo, Wilfried W.,Ozay, Giray Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.6

In the preliminary design stage of an RC 3D-frame, repeated sequential analyses to determine optimal members' sizes and the investigation of the parameters required to minimize the differential column shortening are computational effort consuming, especially when considering various types of loads such as dead load, temperature action, time dependent effects, construction and live loads. Because the desired accuracy at this stage does not justify such luxury, two backpropagation feedforward artificial neural networks have been proposed in order to approximate this information. Instead of using a commercial software package, many references providing advanced principles have been considered to code a program and generate these neural networks. The first one predicts the typical amount of time between two phases, needed to achieve the minimum maximorum differential column shortening. The other network aims to prognosticate sequential analysis results from those of the simultaneous analysis. After the training stages, testing procedures have been carried out in order to ensure the generalization ability of these respective systems. Numerical cases are studied in order to find out how good these ANN match with the sequential finite element analysis. Comparison reveals an acceptable fit, enabling these systems to be safely used in the preliminary design stage.

Calculating the collapse margin ratio of RC frames using soft computing models

Ali Sadeghpour,Giray Ozay 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.83 No.3

The Collapse Margin Ratio (CMR) is a notable index used for seismic assessment of the structures. As proposed by FEMA P695, a set of analyses including the Nonlinear Static Analysis (NSA), Incremental Dynamic Analysis (IDA), together with Fragility Analysis, which are typically time-taking and computationally unaffordable, need to be conducted, so that the CMR could be obtained. To address this issue and to achieve a quick and efficient method to estimate the CMR, the Artificial Neural Network (ANN), Response Surface Method (RSM), and Adaptive Neuro-Fuzzy Inference System (ANFIS) will be introduced in the current research. Accordingly, using the NSA results, an attempt was made to find a fast and efficient approach to derive the CMR. To this end, 5016 IDA analyses based on FEMA P695 methodology on 114 various Reinforced Concrete (RC) frames with 1 to 12 stories have been carried out. In this respect, five parameters have been used as the independent and desired inputs of the systems. On the other hand, the CMR is regarded as the output of the systems. Accordingly, a double hidden layer neural network with Levenberg-Marquardt training and learning algorithm was taken into account. Moreover, in the RSM approach, the quadratic system incorporating 20 parameters was implemented. Correspondingly, the Analysis of Variance (ANOVA) has been employed to discuss the results taken from the developed model. Additionally, the essential parameters and interactions are extracted, and input parameters are sorted according to their importance. Moreover, the ANFIS using Takagi-Sugeno fuzzy system was employed. Finally, all methods were compared, and the effective parameters and associated relationships were extracted. In contrast to the other approaches, the ANFIS provided the best efficiency and high accuracy with the minimum desired errors. Comparatively, it was obtained that the ANN method is more effective than the RSM and has a higher regression coefficient and lower statistical errors.

Minimization of differential column shortening and sequential analysis of RC 3D-frames using ANN

Wilfried W. Njomo,Giray Ozay 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.6

In the preliminary design stage of an RC 3D-frame, repeated sequential analyses to determineoptimal members’ sizes and the investigation of the parameters required to minimize the differential columnshortening are computational effort consuming, especially when considering various types of loads such asdead load, temperature action, time dependent effects, construction and live loads. Because the desiredaccuracy at this stage does not justify such luxury, two backpropagation feedforward artificial neuralnetworks have been proposed in order to approximate this information. Instead of using a commercialsoftware package, many references providing advanced principles have been considered to code a programand generate these neural networks. The first one predicts the typical amount of time between two phases,needed to achieve the minimum maximorum differential column shortening. The other network aims toprognosticate sequential analysis results from those of the simultaneous analysis. After the training stages,testing procedures have been carried out in order to ensure the generalization ability of these respectivesystems. Numerical cases are studied in order to find out how good these ANN match with the sequentialfinite element analysis. Comparison reveals an acceptable fit, enabling these systems to be safely used in thepreliminary design stage.

Chemical Composition and Its Relationship to In vitro Gas Production of Several Tannin Containing Trees and Shrub Leaves

Kamalak, Adem,Canbolat, Onder,Gurbuz, Yavuz,Ozay, Osman,Ozkose, Emin Asian Australasian Association of Animal Productio 2005 Animal Bioscience Vol.18 No.2

The aim of this experiment was to determine the chemical composition of six commonly utilized fodder trees and shrub species in Turkey, namely Glycrrhiza glabra L, Arbutus andrachne, Carpinus betilus, Juniperus communis, Quercus libari L and Pistica lentiscus and its relationship with gas production and estimated parameters when incubated with rumen fluid in vitro. There were significant (p<0.001) differences between leaves in terms of crude protein (CP), acid detergent fiber (ADF), total condensed tannin (TCT), bound condensed tannin (BCT) and soluble condensed tannin (SCT). Crude protein contents ranged from 5.74% (Juniperus communis) to 12.59% (Glycrrhiza glabra L). Acid detergent fiber contents ranged from 25.14% (Glycrrhiza glabra L) to 39.23% (Juniperus communis). Total condensed tannin (TCT) contents of leaves ranged from 4.34% (Quercus libari L) to 20.34% (Juniperus communis). Acid detergent fiber (ADF) and total condensed tannin contents of leaves were negatively correlated with gas productions and some estimated parameters. Potential gas productions (A) of Glycrrhiza glabra L, Arbutus andrachne, Quercus libari L and Pistica lentiscus were significantly (p<0.001) higher than those of Carpinus betilus and Juniperus communis whereas gas production rate (${\mu}_{24}$) of Pistica lentiscus was significantly (p<0.001) higher than the others. Time (h) to produce 50% of total gas pool size ($T_{50}$) of Juniperus communis was significantly (p<0.001) lower than that of Carpinus betilus whereas time (h) to produce 90% of total gas pool size ($T_{90}$) of Juniperus communis was significantly lower than the others except for Pistica lentiscus. The metabolizable energy (ME) contents of leaves ranged from 8.86 to 10.39 MJ $kg^{-1}$ DM. The results obtained in this study suggested that browse species had a significant effect on chemical composition, gas production and estimated parameters of leaves. Leaves from Glycrrhiza glabra L with a considerable amount of CP had a high rank value in terms of ME. Therefore leaves from Glycrrhiza glabra L may have a high potential value for small ruminant animals in terms of rumen and whole digestibility. Leaves from other species studied require protein supplementation when they are the only feed consumed by ruminant animals.

A Retrospective Multicenter Evaluation of Cutaneous Melanomas in Turkey

Gamsizkan, Mehmet,Yilmaz, Ismail,Buyukbabani, Nesimi,Demirkesen, Cuyan,Demiriz, Murat,Cetin, Emel Dikicioglu,Ince, Umit,Akalin, Taner,Demirkan, Nese Calli,Lebe, Banu,Erdem, Ozlem,Gokoz, Ozay,Sakiz, Da Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.23

Background: We defined melanoma distribution in a large series of Turkish patients and evaluated the prognostic parameters of melanomas. Materials and Methods: A total of 1574 patients' data was retrospectively collected at 18 centers in Turkey. Demographic characteristics were questioned and noted. Prognostic parametres were evaluated based on sentinel lymph node involvement. Results: Mean age was 56.7 (4-99) years. While 844 (53.6%) cases were male, 730 (46.4%) cases were female. One thousand four hundred forty-seven (92%) cases were invasive melanoma and 127 (8%) cases were in-situ melanoma. The most common histopathological form was the superficial spreading melanoma (SSM) which was found in 549 patients (37.9%). It was followed by nodular melanoma in 379 (26.2%), acral lentiginous melanoma (ALM) in 191 (13.2%) and lentigo maligna melanoma in 132 (9.1%), respectively. On univariate analysis, lymphovascular invasion (p<0.001), tumor thickness (p<0.001), histopathological subtype (p<0.001), Clark level (p=0.001), ulceration (p<0.001), ${\geq}6/mm^2$ mitosis (p=0.005), satellite formation (p=0.001) and gender (p=0.03) were found to be associated with sentinel lymph node positivity. Regression was associated with sentinel lymph node negativity (p=0.017). According to multivariate analysis, lymphovascular invasion and tumor thickness were significant independent predictive factors of SLN positivity. Patient age, tumor localization, precursor lesions, lymphocytic infiltration and neurotropism were not related with sentinel lymph node involvement. Conclusions: In this retrospective analysis, it was found that the prevalence of SSM is at a lower rate while the prevalence of ALM is at a higher rate when compared to western countries. According to Breslow index; most of the melanoma lesions' thickness were greater than 2 mm, corresponding Clark IV. Vascular invasion and tumor thickness are the most important factors for sentinel lymph node involvement.