Okan Üniversitesi / Okan University

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Citation Count: 3
1.02 - Polyphenols, Bioavailability and Potency
(Elsevier, 2022) Ozdal,T.; Kamiloglu,S.
Polyphenols are plant secondary metabolites comprising of a large class of compounds, which can be broadly classified as flavonoids including flavonols, flavones, flavanones, flavanols, isoflavones, anthocyanins and non-flavonoids including phenolic acids, tannins, stilbenes, and lignans. Polyphenols have important health-promoting effects according to their antioxidant, anti-inflammatory, antimicrobial and anticancer properties, among others. Importantly, the health-promoting effect of polyphenols greatly depend on their bioaccessibility and bioavailability in the digestive tract and circulatory system. Due to their consequences for bioavailability and human health, the interactions between dietary components, particularly phenolic compounds and gut microbiota, have gained significant attention. An overview of the reciprocal relationship between all subclasses of phenolic compounds and gut microbiota is presented in this chapter, as well as the importance of such interactions to bioavailability and human health. © 2022 Elsevier Inc. All rights reserved.
2000 sonrası bankacılık sektöründe kriz yönetimi ve Şekerbank modeli
(2011) Onar, Hale; Günceler, Bülent; İşletme / Business Administration
Gelişmekte olan bir ülke olan Türkiye ekonomik yapısına bağlı olarak dönem dönem finansal krizler yaşamıştır. Yaşanan krizlerden bankacılık sektörü ve finansal kurumlar sektörel yapıları, ürettikleri ve sundukları ürünlerin özellikleri nedeniyle önemli ölçüde etkilenmişlerdir ve bunlara yönelik düzenlemeler, yeniden yapılandırma çalışmaları gündeme gelerek uygulanmıştır. Bu bağlamda bankacılık sektöründe potansiyel kriz veya krizler ortaya çıkmadan önlenmesi, kriz dönemi sonrasında ise durum analizi yapılması büyük bir önem taşımaktadır. Bu çalışmanın amacı, 2000 sonrası BankacılıkSektöründe Kriz yönetimi ve Son yaşanan Küresel Krizin etkilerini ve kriz yönetim stratejilerini ortaya koymaktır. Özellikle 2008 yılının son çeyreğinde ABD?de başlayan, batıdan doğuya doğru tüm ülkeleri çeşitli şekillerde etkileyen küresel ekonomik krizden dünya bankaları yanı sıra Türkiye özelinde Şekerbank T.A.Ş?nin etkilenme düzeyi ve bu süreçte uygulanan yönetsel ve örgütsel politikalarının neler olduğu Birim Müdürleri algıları doğrultusunda araştırılmıştır. Banka içinde Birimlerin Müdürleri ile anket ve mülakat yöntemi kullanılarak gerçekleştirilen çalışmada; kriz nedeniyle birçok kurumuniş hacminin ve müşteri sayısının önemli oranda azaldığı ve bu yönüyle kurumların krizden etkilendiği ortaya çıkmıştır. Birçok kurum üzerindeki yönetsel ve örgütsel etkiler göz önüne alındığında, Şekerbank özelinde 2000 ve 2001 krizi dönemindeki yeniden yapılanma ve düzenlemeler sayesinde küresel krizde yönetsel, örgütsel politika ve uygulamalar anlamında önemli olumsuzluklar yaşanmamış ancak banka içinde bazı tedbirlerin alındığı ortaya çıkmıştır.
Citation Count: 0
3-D NUMERICAL MODELLING OF GROUND VIBRATION WAVES INDUCED BY BLASTING AT A QUARY
(int Scientific Conference Sgem, 2010) Aksoy, Mehmet; Kahriman, Ali; Makine / Machinery
Ground vibrations arising from excavation with blasting is one of the environmental problems in mining industry. The prediction of ground vibrations and the realization of controlled blasting based on this prediction have a great importance in order to minimize the environmental effects of blasting. The purpose of this study is to analyze the ground vibrations induced by blasting at Akyol Quarry which selected as a test site after the determination of the geomechanical properties of the rock mass with a computer software (AUTODYN 3D) that is able to model three dimensionally. During the field study, samples were taken from the different regions of the quarry. On these samples, geomechanical properties of the intact rock samples were determined. Then, geomechanical properties of the rock mass were estimated. In the numerical modeling stage, four main numerical models were prepared in the AUTODYN software by using the data obtained from the field and laboratory studies. The data obtained from these model runs was compared to the data obtained in the field measurements. As a result of this comparison, the model that would be used for future studies was selected.
Citation Count: 0
3-D numerical modelling of ground vibration waves induced by blasting at a quary
(2010) Aksoy,M.; Kahriman,A.; Makine / Machinery
Ground vibrations arising from excavation with blasting is one of the environmental problems in mining industry. The prediction of ground vibrations and the realization of controlled blasting based on this prediction have a great importance in order to minimize the environmental effects of blasting. The purpose of this study is to analyze the ground vibrations induced by blasting at Akyol Quarry which selected as a test site after the determination of the geomechanical properties of the rock mass with a computer software (AUTODYN 3D) that is able to model three dimensionally. During the field study, samples were taken from the different regions of the quarry. On these samples, geomechanical properties of the intact rock samples were determined. Then, geomechanical properties of the rock mass were estimated. In the numerical modeling stage, four main numerical models were prepared in the AUTODYN software by using the data obtained from the field and laboratory studies. The data obtained from these model runs was compared to the data obtained in the field measurements. As a result of this comparison, the model that would be used for future studies was selected.
Citation Count: 0
A 3-year-old child with multi-drug resistant epilepsy responding to pharmacological and nonpharmacological treatments
(Taylor & Francis Ltd, 2023) Coskun, Yesim; Yildirim, Canan
Introduction: Despite the development of new antiseizure drugs (ASDs), around one third of epilepsy patients become refractory to treatment or experience adverse events due to ASDs. Therefore, discovery of new ASDs and new therapy options are crucial to improve the quality of life. Herein, we report a 3-year-old child with multi-drug resistant epilepsy caused by perinatal asphyxia whose seizures were reduced by 90% after the introduction of ketogenic diet, vagal nerve stimulation (VNS) AspireSR (SR-seizure response) and oral cannabidiol.Case presentation: A 9-month-old female infant had a history of multidrug resistant epilepsy due to perinatal asphyxia. At admission, she was experiencing up to 20-25 seizures per day lasting for 2-3 minutes. In addition to antiseizure drugs (ASDs), she was put on ketogenic diet (KD), vagal nerve stimulation (VNS) aspire seizure response (AspireSR) was inserted and oral cannabidiol (CBD) was started sequentially. Using pharmacological and nonph armacological therapies, her seizures have been reduced by 90%.Conclusion: The concurrent use of pharmacological and nonpharmacological therapies may be beneficial to improve seizures in infants with multi- Furthermore, our patient is the youngest child inserted VNS AspireSR in Turkey.
Citation Count: 0
3D and 4D printing of MXene-based composites: from fundamentals to emerging applications
(Royal Soc Chemistry, 2024) Bigham, Ashkan; Zarepour, Atefeh; Khosravi, Arezoo; Iravani, Siavash; Zarrabi, Ali; Genetik ve Biyomühendislik / Genetic and Bio-Engineering
The advent of three-dimensional (3D) and four-dimensional (4D) printing technologies has significantly improved the fabrication of advanced materials, with MXene-based composites emerging as a particularly promising class due to their exceptional electrical, mechanical, and chemical properties. This review explores the fundamentals of MXenes and their composites, examining their unique characteristics and the underlying principles of their synthesis and processing. We highlight the transformative potential of 3D and 4D printing techniques in tailoring MXene-based materials for a wide array of applications. In the field of tissue regeneration, MXene composites offer enhanced biocompatibility and mechanical strength, making them ideal for scaffolds and implants. For drug delivery, the high surface area and tunable surface chemistry of MXenes enable precise control over drug release profiles. In energy storage, MXene-based electrodes exhibit superior conductivity and capacity, paving the way for next-generation batteries and supercapacitors. Additionally, the sensitivity and selectivity of MXene composites make them excellent candidates for various (bio)sensing applications, from environmental monitoring to biomedical diagnostics. By integrating the dynamic capabilities of 4D printing, which introduces time-dependent shape transformations, MXene-based composites can further adapt to complex and evolving functional requirements. This review provides a comprehensive overview of the current state of research, identifies key challenges, and discusses future directions for the development and application of 3D and 4D printed MXene-based composites. Through this exploration, we aim to underscore the significant impact of these advanced materials and technologies on diverse scientific and industrial fields. This review highlights the developments in the 3D/4D printing of MXene-based composites, focusing on their application in tissue regeneration, drug delivery, sensing, and energy storage.
Citation Count: 1
3D FEA of Hollow and Solid Design Zirconia Dental Dowels
(Wiley, 2016) Kayahan, Mehmet Baybora; Ozkurt-Kayahan, Zeynep; Yay, Kubilay; Kazazoglu, Ender
PurposeThe aim of this study was to evaluate the stress distribution of hollow and solid design zirconia dowels. Materials and MethodsFinite element analysis (FEA) was used to investigate the influence of different dowel designs on the stress distribution of zirconia dowels. The coronal diameter of the dowel was 2.2 mm, the apical diameter was 1.8 mm, and the length was 15 mm. The diameter of the hollow space was 1.2 mm. Occlusal forces (both parallel and oblique) of 100 N were applied from the wider edge of the dowels simulating loads acting on the incisor during clenching and incising. The results were expressed in terms of von Mises criteria. ResultsFEA revealed differences in stress distribution. During parallel load, the maximum tensile stress of the hollow design (89.40 MPa) was greater than the solid design (43.30 MPa). During oblique load, the maximum tensile stress of the hollow design (1437.90 MPa) was greater than the solid design (917.96 MPa). The maximum deformation was observed in the coronal part of the dowel in both designs under the two load directions. ConclusionsFEA results showed that the hollow design zirconia dowels presented higher tensile stress.
Citation Count: 3
A 3D finite element analysis of stress distribution on different thicknesses of mineral trioxide aggregate applied on various sizes of pulp perforation
(Springer Heidelberg, 2020) Ozkurt-Kayahan, Zeynep; Turgut, B.; Akin, H.; Kayahan, M. B.; Kazazoglu, E.; Periodontoloji / Periodontology
Objectives The aim of this study was to evaluate the stress distribution on different thicknesses of mineral trioxide aggregate (MTA) placed on various widths of pulp perforations during the condensation of the composite resin material. Materials and methods The mandibular molar tooth was modeled by COSMOSWorks program (SolidWorks, Waltham, MA). Three finite elemental analysis models representing 3 different dimensions of pulp perforations, 1, 2, and 3 mm in diameter, were created. The perforation area was assumed as filled with MTA with different thicknesses, 1, 2, and 3 mm for each pulp perforation width, creating a total of 9 different models. Then, a composite resin material was layered on MTA for each model. A 66.7 N load was applied and an engineering simulation program (ANSYS, Canonsburg, US) was used for the analysis. Results were presented considering von Mises stress criteria. Results As MTA thickness increased, the stress values recorded within the area between pulp and MTA decreased. Strain was decreased when the thickness of MTA increased. Conclusions Stresses at MTA-pulp interface and strain on MTA decreased with the increase in MTA thickness.
Citation Count: 5
4/3 problem, Poynting theorem, and electromagnetic energy-momentum tensor
(Canadian Science Publishing, 2015) Kholmetskii, Alexander L.; Missevitch, Oleg V.; Yarman, Tolga; Enerji Sistemleri Mühendisliği / Energy Systems Engineering
We show that the familiar 4/3 problem originates from the incorrect determination of the momentum of the electromagnetic field generated by an isolated charged particle, which results from an incorrect application of the Poynting theorem to the field. To demonstrate this, we consider a macroscopic problem: splitting a charged oil droplet into two identical smaller droplets in the rest frame K of the original droplet, and in another inertial frame K' moving with respect to K with some constant velocity, and arrive at a physically senseless solution in the framework of the standard approach. To solve this problem in a correct way, we suggest a modified Poynting theorem for an isolated charge and recalculate the momentum of the electromagnetic field of this charge, which yields the usual relativistic relationship between the field energy and momentum. Our approach is not at odds with the idea about "Poincare stresses"; however, in contrast to the standard method, it provides a usual relationship between the "Poincare stress-energy" and the associated momentum stress component. Finally, the continuity equation in four-dimensional form for the case of isolated moving charge is also proposed, which completely resolves the 4/3 problem.
Citation Count: 0
5-Year clinical performance of ceramic onlay and overlay restorations luted with light-cured composite resin
(Elsevier Sci Ltd, 2024) Yurdaguven, Gulsah Yenier; Ciftcioglu, Elif; Kazokoglu, Fatma Sehnaz; Kayahan, Mehmet Baybora; Endodonti / Endodontics
Objectives: This prospective clinical trial evaluated the clinical performance of ceramic partial coverage indirect adhesive restorations (PCIARs) in posterior teeth luted with a light-cured composite resin. Methods: From April 2016 to January 2017, a total of 60 patients (27 males, 33 females; mean age: 42.2 +/- 10.86 years old) received 83 glass-ceramic PCIARs (26 onlay, 57 overlay) made of IPS Emax CAD (Ivoclar Vivadent). All restorations were luted with a light-cured composite resin (Filtek Z250, 3 M ESPE) by two operators. Two independent calibrated examiners blinded to the operators performing the treatment evaluated the restorations at baseline, 1-year, and 5-year following FDI World Dental Federation criteria including esthetic, functional, and biological properties. Data were analyzed with the Friedman test and the Wilcoxon sign test (p p < 0.05). Results: None of the restorations failed due to fracture or retention loss. One restoration was clinically unsatisfactory because of secondary caries. Marginal staining (p:0.000), marginal adaptation (p:0.018) showed significant differences between 1-year and 5-year recall. Conclusions: The PCIARs demonstrated excellent clinical performance at 1-year period. The degradation parameters appeared as minor staining and minor irregularities after 5-year, without any affect on the clinical performance.
Citation Count: 0
5th and 6th grade students' perceptions of communication
(Pegem Akad Yayincilik Egitim Danismanlik Hizmetleri Tic Ltd Sti, 2020) Sarkin, Dondu Bahar Sahin; Duran, Aysemin; Eğitim Bilimleri / Educational Sciences
This study aims to examine how 5th and 6th grade students perceive the phenomenon of communication. It was designed as a qualitative research and the phenomenological method was used. Totally, 80 students constituted the study group. A two-part "Communication Perception Form" was created by the researchers in order to determine the perceptions of the students regarding the phenomenon of communication. Content analysis technique was used in evaluating the data obtained in this study. Data on the phenomenon of communication were gathered among five categories (nature, emotion, food, existence, tool/mediator). In the visual metaphors of the students, it was seen that they drew telephone and talking people mostly. The metaphors developed by the 5th and 6th graders, which are the first levels of secondary school, can be considered as important indicators for understanding the positive and negative effects of communication on students. In this study, where communication generally evokes speech or correspondence, it can be suggested that students acquire this skill in various fields through programs, since it is seen that students make more in-depth descriptions in visual expression.
Citation Count: 0
The 9th IEEE International Workshop on Engineering Semantic Agents - Semantics, Agents and Intelligence (ESAS 2014)
(Institute of Electrical and Electronics Engineers Inc., 2014) Elçi,A.; Celik,D.; Orgun,M.A.; Rahnama,B.; Unland,R.
[No abstract available]
AB ile Nijerya arasındaki tedarik zinciri yönetimi uygulamaları ve zorlukları: Uluslararası ticaret araştırması
(2019) Usman, Said Abdullahi; Köseoğlu, Ahmet Murat
Çalışma, Nijerya ve AB arasındaki uluslararası ticareti etkileyen tedarik zinciri yönetimi zorlukları üzerinde yürütülmüştür. Araştırma, ulusal veri tabanından ikincil verileri ve 2007'den 2018'e kadar olan çeşitli kaynakları kullanarak saf nitel yaklaşımı kullandı. Araştırma, dünyanın iki farklı bölgesinden (Nijerya ve AB) lojistik ve tedarik zinciri uygulamalarının nasıl değerlendirildiğinin ve içerdiği bileşenleri ve her iki taraf arasındaki dış ticareti nasıl etkilediğinin genel bir görünümünü sunmaktadır. Araştırma, organizasyonların performansını etkileyecek ve Nijerya ile AB arasındaki ticareti artıracak etkin lojistik yönetimi ve tedarik zinciri uygulamalarına yol açan faktörleri ve özellikleri bulmayı amaçlamaktadır. . Konular Giriş, tedarik zinciri yönetimi hakkında genel fikir, Nijerya ve onun uluslararası ticareti hakkında genel bilgiler, AB'nin şu anki gözden geçirmesi ve Batı Afrika ile olan uluslararası ticaretinin tam anlamıyla Nijerya'dan oluşması. Son olarak, etkin bir lojistik yönetimi ile Nijerya'ya yönelik (Dış) ticaret sektöründe iyileşme ve büyümenin sağlanmasına yardımcı olacak önerilerde bulunulmuştur.
Citation Count: 4
Aberrant socs3 promoter methylation as a noninvasive diagnostic biomarker for locally advanced prostate cancer;
(Logos Medical Publishing, 2020) Demircan Tan,B.; Turan,T.; Yucel,B.; Altundag Kara,S.; Salman Yilmaz,S.; Yildirim,A.; Acil Tıp / Emergency Medicine
Objective: The aim of this study was to investigate the promoter methylation status of Rasassociated domain family 1A (RASSF1A), O-6-methylguanine-DNA methyltransferase (MGMT), Phosphatase with tensin homology (PTEN) and Suppressor of cytokine signaling 3 (SOCS3) tumor suppressor genes and evaluate the clinical utility of these genes as noninvasive, bloodbased epigenetic biomarkers for the diagnosis of Prostate Cancer (PCa). Method: A total of 41 consecutive patients and 10 healthy control groups were enrolled in the study. Pyrosequencing was performed to analyze the methylation levels of the promoter regions of the four tumor suppressor genes in patients compared to healthy controls. Results: The promoter methylation levels of RASSF1A, MGMT, PTEN and SOCS3 did not differ between the patient and control groups. However, SOCS3 promoter methylation level was significantly higher for patients having locally advanced PCa compared to those having localized PCa (p<0.05). Conclusion: Our results indicated that SOCS3 could be a useful, noninvasive blood-based epigenetic biomarker for the diagnosis of locally advanced PCa. © Istanbul Medeniyet University Faculty of Medicine.
Citation Count: 1
ABSTRACT CAPACITY OF REGIONS AND COMPACT EMBEDDING WITH APPLICATIONS
(Springer, 2011) Shakhmurov, Veli
The weighted Sobolev-Lions type spaces W-p,gamma(l) (Omega; E) boolean AND L-p,L-gamma (Omega; E-0) are studied, where E-0, E are two Banach spaces and E-0 is continuously and densely embedded on E. A new concept of capacity of region Omega is an element of R-n in Wp,gamma(l)(Omega; E-0, E) is introduced. Several conditions in terms of capacity of region Omega and interpolations of E-0 and E are found such that ensure the continuity and compactness of embedding operators. In, particular, the most regular class of interpolation spaces E-alpha between E-0 and E, depending of alpha and l, are found such that mixed differential operators D-alpha are bounded and compact from W-p,gamma(l)(Omega; E-0, E) to E-alpha-valued L-p,L-gamma spaces. In applications, the maximal regularity for differential-operator equations with parameters are studied.
Citation Count: 4
Abstract Differential Equations with VMO Coefficients in Half Space and Applications
(Springer Basel Ag, 2016) Shakhmurov, Veli
In this paper, L (p) -separability properties of boundary value problems for elliptic and parabolic differential-operator equations with VMO coefficients are studied in half plane. In application, the maximal regularity properties of the anisotropic elliptic equation and system of equations with VMO coefficients are derived.
Citation Count: 4
Abstract Elliptic Equations with Integral Boundary Conditons
(Shanghai Scientific Technology Literature Publishing House, 2016) Shakhmurov, Veli
This paper focuses on nonlocal integral boundary value problems for elliptic differential-operator equations. Here given conditions guarantee that maximal regularity and Fredholmness in L-p spaces. These results are applied to the Cauchy problem for abstract parabolic equations, its infinite systems and boundary value problems for anisotropic partial differential equations in mixed L-p norm.
Citation Count: 2
Abstract elliptic operators appearing in atmospheric dispersion
(Springeropen, 2014) Shakhmurov, Veli B.; Sahmurova, Aida
In this paper, the boundary value problem for the differential-operator equation with principal variable coefficients is studied. Several conditions for the separability and regularity in abstract L-p-spaces are given. Moreover, sharp uniform estimates for the resolvent of the corresponding elliptic differential operator are shown. It is implies that this operator is positive and also is a generator of an analytic semigroup. Then the existence and uniqueness of maximal regular solution to nonlinear abstract parabolic problem is derived. In an application, maximal regularity properties of the abstract parabolic equation with variable coefficients and systems of parabolic equations are derived in mixed L-p-spaces.
Citation Count: 0
Abstract elliptic operators appearing in atmospheric dispersion (vol 2014, pg 43, 2014)
(Springer international Publishing Ag, 2014) Shakhmurov, Veli B.; Sahmurova, Aida
[No Abstract Available]
Citation Count: 11
Abstract parabolic problems with parameter and application
(Elsevier Science inc, 2013) Shakhmurov, Veli B.; Sahmurova, Aida
In this work, the uniform well-posedenes of singular perturbation problems for parameter dependent parabolic differential-opera tor equations is established. These problems occur in phytoremediation modelling. (C) 2013 Elsevier Inc. All rights reserved.

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