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Öğe Half-lightlike submanifolds with planar normal sections in R24(Tubitak Scientific & Technological Research Council Turkey, 2014) Erdogan, Feyza Esra; Gunes, Rifat; Sahin, BayramWe investigate half-lightlike submanifolds with planar normal sections of 4-dimensional pseudo-Euclidean space. We obtain necessary and sufficient conditions for a half-lightlike submanifold of R-2(4) such that it has degenerate or nondegenerate planar normal sections.Öğe Half-lightlike submanifolds with planar normal sections in R4 2(Turkish Journal of Mathematics, 2014) Erdogan, Feyza Esra; Güneş, Rıfat; Şahin, BayramAbstract: We investigate half-lightlike submanifolds with planar normal sections of 4-dimensional pseudo-Euclidean space. We obtain necessary and sufficient conditions for a half-lightlike submanifold of R 4 2 such that it has degenerate or nondegenerate planar normal sections.Öğe The investigation of the effect of NAD, H2O2 and weak magnetic field on the antibacterial mechanism of isoniazid (INH) that first line antibiotic against M. tuberculosis agent(2020) Gunal, Selami; Erdogan, Feyza Esra; Batcioglu, KadirAbstract: Tuberculosis is an infectious disease, which is caused by the Mycobacterium tuberculosis complex. This disease leads to up to 1.3 million deaths out of more than eight million cases every year. A prodrug called isoniazid has been proven to be effective and widely used in the treatment of infections caused by tuberculosis. Despite its use for more than six decades clinically, the action mechanism of this prodrug is yet to be elucidated. INH action agains mycobacteria requires catalase?peroxidase (KatG) function, and IN-NAD adduct formation is catalyzed in vitro by M. tuberculosis KatG under a variety of conditions. Low-intensity EMF (Electromagnetic Field) has been used in therapeutic practices in addition to its use in telecommunication systems and food protection. EMF is used in medicine and food industries especially for its bacte-ricidal effects. In this study, we aimed to investigate the effects of weak magnetic field application and the addition of NAD and H2O2 on the action mechanism of isoniazid. We added H2O2 and NAD individually and together, to the different groups at varying concentrations. Also, one experimental group was exposed to a 5mT, 50Hz magnetic field for 4 to 5 hours per day (total of 45 hours in 10 days). The agar proportion method was used to evaluate the results. It was determined that the addition of 100 ?M NAD and H2O2 together increased the effectiveness of isoniazid to some extent. However, the application of a weak magnetic field did not change the effectiveness of the drug.Öğe Lightlike Submanifolds with Planar Normal Section in Semi Riemannian Product Manifolds(Int Electronic Journal Geometry, 2016) Erdogan, Feyza Esra; Yildirim, CumaliIn the present paper we give conditions for screen semi invariant lightlike submanifolds of a semi-Riemannian product manifold to have degenerate planar normal sections. Also we give sufficient and efficient conditions for screen invariant and screen anti invariant lightlike submanifold of a semi-Riemanniann product manifold to have non-degenerate planar normal sections.Öğe LIGHTLIKE SURFACES WITH PLANAR NORMAL SECTIONS IN MINKOWSKI 3-SPACE(Int Electronic Journal Geometry, 2014) Erdogan, Feyza Esra; Sabin, Bayram; Gunes, RifatIn this paper we study lightlike surfaces of Minkowski 3- space such that they have degenerate or non-degenerate planar normal sections. We first show that every lightlike surface of Minkowski 3- space has degenerate planar normal sections. Then we study lightlike surfaces with non-degenerate planar normal sections and obtain a characterization for such lightlike surfaces.Öğe On a Study of the Totally Umbilical Semi-Invariant Submanifolds of Golden Riemannian Manifolds(Gazi Univ, 2018) Erdogan, Feyza Esra; Yildirim, CumaliThe Golden Ratio is fascinating topic that continually generated news ideas. A Riemannian manifold endowed with a Golden Structure will be called a Golden Riemannian manifold. Precisely, we can say that an (1,1)-tensor field (P) over bar on a m-dimensional Riemann manifold (<(M,<(g)over bar>)over bar>) is a Golden structure if it satisfies the equation (P) over bar (2) = (P) over bar + Id, where Id is identity map on M. Furthermore, g((P) over bar, (X) over bar, (Y) over bar) = (g) over bar((X) over bar,(P) over bar (Y) over bar), the Riemannian metric is called (P) over bar -compatible and ((M) over bar,(g) over bar,(P) over bar) is named a Golden Riemannian manifold. The main purpose of the present paper is to study the geometry of Riemannian manifolds endowed with Golden structures. For this purpose, we study totally umbilical semi-invariant submanifold of the Golden Riemannian manifolds. Also, we obtain integrability conditions of the distributions and investigate the geometry of foliations.Öğe ON SEMI-INVARIANT SUBMANIFOLDS OF ALMOST COMPLEX CONTACT METRIC MANIFOLDS(Univ Nis, 2016) Yildirim, Cumali; Erdogan, Feyza EsraIn this article, we study semi-invariant submanifolds of almost complex contact metric manifolds.We defined and investigated semi-invariant submanifolds of almost complex contact metric manifolds. We found necessary and sufficient conditions to be integrable and totally geodesic for distributions D defined on M. Also we obtained necessary and sufficient conditions to be integrable and totally geodesic for distributions D-perpendicular to defined on M.Öğe Semi-Invariant Submanifolds of Golden Riemannian Manifolds(Amer Inst Physics, 2017) Erdogan, Feyza Esra; Yildirim, CumaliIn this article we studied semi-invariant submanifolds of the Golden Riemannian manifold. We give integrability condition of the distributions and investigate the geometry of foliations. We also find necessary and sufficient conditions for a semi-invariant submanifold to be totally geodesic.
