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On slant Riemannian submersions for cosymplectic manifolds
Irem Kupeli Erken,Cengizhan Murathan 대한수학회 2014 대한수학회보 Vol.51 No.6
In this paper, we introduce slant Riemannian submersions from cosymplectic manifolds onto Riemannian manifolds. We obtain some results on slant Riemannian submersions of a cosymplectic manifold. We also give examples and inequalities between the scalar curvature and squared mean curvature of fibres of such slant submersions in the cases where the characteristic vector field is vertical or horizontal.
ON SLANT RIEMANNIAN SUBMERSIONS FOR COSYMPLECTIC MANIFOLDS
Erken, Irem Kupeli,Murathan, Cengizhan Korean Mathematical Society 2014 대한수학회보 Vol.51 No.6
In this paper, we introduce slant Riemannian submersions from cosymplectic manifolds onto Riemannian manifolds. We obtain some results on slant Riemannian submersions of a cosymplectic manifold. We also give examples and inequalities between the scalar curvature and squared mean curvature of fibres of such slant submersions in the cases where the characteristic vector field is vertical or horizontal.
On Semiparallel and Weyl-semiparallel Hypersurfaces of Kaehler Manifolds
Ozgur, Cihan,Murathan, Cengizhan,Arslan, Kadri Department of Mathematics 2009 Kyungpook mathematical journal Vol.49 No.1
We study on semiparallel and Weyl semiparallel Sasakian hypersurfaces of Kaehler manifolds. We prove that a (2n + 1)-dimensional Sasakian hypersurface M of a (2n+2)-dimensional Kaehler manifold $\widetilde{M}^{2n+2}$ is semiparallel if and only if it is totally umbilical with unit mean curvature, if dimM = 3 and $\widetilde{M}^4$ is a Calabi-Yau manifold, then $\widetilde{M}$ is flat at each point of M. We also prove that such a hypersurface M is Weyl-semiparallel if and only if it is either an ${\eta}$-Einstein manifold or semiparallel. We also investigate the extended classes of semiparallel and Weyl semiparallel Sasakian hypersurfaces of Kaehler manifolds.
PSEUDO SYMMETRIC AND PSEUDO RICCI SYMMETRIC WARPED PRODUCT MANIFOLDS
De, Uday Chand,Murathan, Cengizhan,Ozgur, Cihan Korean Mathematical Society 2010 대한수학회논문집 Vol.25 No.4
We study pseudo symmetric (briefly $(PS)_n$) and pseudo Ricci symmetric (briefly $(PRS)_n$) warped product manifolds $M{\times}_FN$. If M is $(PS)_n$, then we give a condition on the warping function that M is a pseudosymmetric space and N is a space of constant curvature. If M is $(PRS)_n$, then we show that (i) N is Ricci symmetric and (ii) M is $(PRS)_n$ if and only if the tensor T defined by (2.6) satisfies a certain condition.
On Lorentzian α-Sasakian Manifolds
Yildiz, Ahmet,Murathan, Cengizhan Department of Mathematics 2005 Kyungpook mathematical journal Vol.45 No.1
The present paper deals with Lorentzian ${\alpha}-Sasakian$ manifolds with conformally flat and quasi conform ally flat curvature tensor. It is shown that in both cases, the manifold is locally isometric with a sphere $S^{2^{n}+1}(c)$. Further it is shown that an Lorentzian ${\alpha}-Sasakian$ manifold with R(X, Y).C = 0 is locally isometric with a sphere $S^{2^{n}+1}(c)$, where c = ${\alpha}^2$.
CONTACT CR-WARPED PRODUCT SUBMANIFOLDS IN KENMOTSU SPACE FORMS
ARSLAN, KADRI,EZENTAS, RIDVAN,MIHAl, ION,MURATHAN, CENGIZHAN Korean Mathematical Society 2005 대한수학회지 Vol.42 No.5
Recently, Chen studied warped products which are CR-submanifolds in Kaehler manifolds and established general sharp inequalities for CR-warped products in Kaehler manifolds. In the present paper, we obtain sharp estimates for the squared norm of the second fundamental form (an extrinsic invariant) in terms of the warping function for contact CR-warped products isometrically immersed in Kenmotsu space forms. The equality case is considered. Some applications are derived.
A Class of Lorentzian α-Sasakian Manifolds
Yildiz, Ahmet,Turan, Mine,Murathan, Cengizhan Department of Mathematics 2009 Kyungpook mathematical journal Vol.49 No.4
In this study we consider ${\varphi}$-conformally flat, ${\varphi}$-conharmonically flat, ${\varphi}$-projectively at and ${\varphi}$-concircularly flat Lorentzian ${\alpha}$-Sasakian manifolds. In all cases, we get the manifold will be an ${\eta}$-Einstein manifold.
Bebis, Hatice,Altunkurek, Serife Zehra,Acikel, Cengizhan,Akar, Ilker,Altunkurek, Serife Zehra Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.8
Background: The aim of this study was to determine beliefs concerning breast self-examination in first- and second-degree relatives of patients with breast cancer and evaluate their breast self-examination (BSE) application. Materials and Methods: A survey study was conducted in an oncology polyclinic and general surgery clinic of a hospital in Ankara, the capital of Turkey with a sample of 140 women. Results: It was determined that 60.7% of the participants had conducted BSE and 48.1% had undergone a clinical breast examination. Perceived selfefficacy of the women who performed BSE were significantly higher compared with women who did not practice BSE (p<0.001) Furthermore, perceived barriers were lower among those who had performed BSE (p<0.001). Logistic regression analysis indicated that women who perceived higher self-efficacy (OR: 1.119, 95% CI: 1.056-1.185, p<0.001) and had regular CBE (OR: 8.250, 95% CI: 3.140-21.884, p<0.001) and educational status (OR: 5.287, 95% CI: 1.480-18.880, p<0.01) were more likely to perform BSE. Conclusions: Findings from this study indicated that perceived barriers, perceived self-efficacy, and educational status could be predictors of BSE behavior among the first- and second-degree relatives of patients with breast cancer. Therefore, BSE training programs that emphasize self-efficacy and address perceived barriers are recommended.
Fibulin-3 as a Diagnostic Biomarker in Patients with Malignant Mesothelioma
Kaya, Halide,Demir, Melike,Taylan, Mahsuk,Sezgi, Cengizhan,Tanrikulu, Abdullah Cetin,Yilmaz, Sureyya,Bayram, Mehmet,Kaplan, Ibrahim,Senyigit, Abdurrahman Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.4
Background: New tumour biomarkers are being intensely investigated for malignant mesothelioma (MM). Fibulin-3 is produced in MM but its role remains uncertain. The aim of this study was to evaluate the validity of measuring serum fibulin-3 in the diagnosis and prognosis of MM. Materials and Methods: This prospective study was performed on 43 patients and 40 healthy controls who were admitted to our hospital between January 2012 and January 2014. Data from MM patients, including demographic and clinical features, routine laboratory data, levels of serum fibulin-3, and treatment outcomes were defined as potential prognostic factors. The receiver operating characteristic (ROC) curve for fibulin-3 was used to detect the cut-off value with highest sensitivity and specificity. Univariate survival analysis was performed using the Kaplan-Meier method in patients with MM. Afterwards, the possible factors identified with univariate analyses were entered into the cox regression analysis. Results: Our results revealed that patients with MM had significantly higher serum levels of fibulin-3 than controls. The results showed that the best cut-off point was 36.6 ng/ml with an AUC (area under the curve)=0.976, sensitivity=93.0% and specificity=90.0. In our study, the initial significant poor prognostic factors were advanced stage, high white blood cell count, high platelet count, high C-reactive protein (p<0.05 for each variable). Later, according to multivariate analysis the results showed only advanced stage as significant parameter (p=0.040). Conclusions: We determined that real use for serum fibulin-3 was not for prognosis but for diagnosis in MM. Also advanced stage was associated with poor MM prognosis.
Lycopene Protects Against Spontaneous Ovarian Cancer Formation in Laying Hens
Kazim Sahin,Engin Yenice,Mehmet Tuzcu,Cemal Orhan,Cengizhan Mizrak,Ibrahim H. Ozercan,Nurhan Sahin,Bahiddin Yilmaz,Birdal Bilir,Bulent Ozpolat,Omer Kucuk 대한암예방학회 2018 Journal of cancer prevention Vol.23 No.1
Background: Dietary intake of lycopene has been associated with a reduced risk of ovarian cancer, suggesting its chemopreventive potential against ovarian carcinogenesis. Lycopene’s molecular mechanisms of action in ovarian cancer have not been fully understood. Therefore, in the present study, we investigated the effects of lycopene on the ovarian cancer formation using the laying hen model, a biologically relevant animal model of spontaneous ovarian carcinogenesis due to high incidence rates similar to humans. Methods: In this study, a total of 150 laying hens at age of 102 weeks were randomized into groups of 50: a control group (0 mg of lycopene per kg of diet) and two treatment groups (200 mg or 400 mg of lycopene per kg of diet, or ~26 and 52 mg/d/hen, respectively). At the end of 12 months, blood, ovarian tissues and tumors were collected. Results: We observed that lycopene supplementation significantly reduced the overall ovarian tumor incidence (P < 0.01) as well as the number and the size of the tumors (P < 0.004 and P < 0.005, respectively). Lycopene also significantly decreased the rate of adenocarcinoma, including serous and mucinous subtypes (P < 0.006). Moreover, we also found that the serum level of oxidative stress marker malondialdehyde was significantly lower in lycopene-fed hens compared to control birds (P < 0.001). Molecular analysis of the ovarian tumors revealed that lycopene reduced the expression of NF-B while increasing the expression of nuclear factor erythroid 2 and its major target protein, heme oxygenase 1. In addition, lycopene supplementation decreased the expression of STAT3 by inducing the protein inhibitor of activated STAT3 expression in the ovarian tissues. Conclusions: Taken together, our findings strongly support the potential of lycopene in the chemoprevention of ovarian cancer through antioxidant and anti-inflammatory mechanisms. (J Cancer Prev 2018;23:25-36)