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Showing papers by "Young Jin Suh published in 2007"


Journal ArticleDOI
TL;DR: In this paper, the authors studied n-dimensional compact minimal hypersurfaces in a unit sphere Sn+1(1) and gave an answer for S. Chern's conjecture.
Abstract: In this paper, we study n-dimensional compact minimal hypersurfaces in a unit sphere Sn+1(1) and give an answer for S. S. Chern's conjecture. We have shown that if S > n, and prove that an n-dimensional compact minimal hypersurface with constant scalar curvature in Sn+1(1) is a totally geodesic sphere or a Clifford torus if , where S denotes the squared norm of the second fundamental form of this hypersurface.

34 citations


Journal ArticleDOI
TL;DR: In this paper, the Jacobi operators R ξ and the Ricci tensor S for real Hopf hypersurfaces were considered and a new commuting condition (R ξ ϕ)S = S(R ǫ ϕ )S = ρ(R Ω ϕ ), where ρ (R Ãǫ Ã )S is a Jacobi operator between R Ã and S Ã.
Abstract: In this paper, we have considered new commuting conditions, that is, (R ξ ϕ)S = S(R ξ ϕ) (resp \((\bar{R}_{N}\phi )S = S(\bar{R}_{N}\phi )\)) between the Jacobi operators R ξ (resp \(\bar{R}_{N}\)), the structure tensor field ϕ and the Ricci tensor S for real hypersurfaces M in \(G_{2}(\mathbb{C}^{m+2})\) With such a condition we give a complete classification of Hopf hypersurfaces M in \(G_{2}(\mathbb{C}^{m+2})\)

34 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that there is no real hypersurface in complex projective space whose structure Jacobi operator is of Codazzi type, and hence, no hypersurfaces in projective spaces.
Abstract: We prove the non existence of real hypersurfaces in complex projective space whose structure Jacobi operator is of Codazzi type

10 citations


Journal ArticleDOI
TL;DR: In this paper, Cheng and Yau gave a characterization of Clifford tori and in a unit sphere S n + 1 (1) (1), where n is the number of vertices in the sphere.
Abstract: In this paper, we give a characterization of Clifford tori and in a unit sphere S n +1 (1). Our results extend the results due to Cheng and Yau [ 4 ], and Wang and Xia [ 11 ].

8 citations


Journal Article
TL;DR: In this article, the existence of real hypersurfaces in either complex projective spaces or complex hyperbolic spaces whose structure Jacobi operator commutes with any other Jacobi operators is proved.
Abstract: We prove the non existence of real hypersurfaces in either complex projective spaces or complex hyperbolic spaces whose structure Jacobi operator commutes with any other Jacobi operator.

4 citations


Journal ArticleDOI
TL;DR: Surgical excision may not always be necessary for papillary lesion of the breast that is diagnosed on core needle biopsy, as shown in patients with papillomatosis or papillary lesions with atypism seen on core needles.
Abstract: 은 양성 유두종 일부에서 비정형상피증식증이나 관상피내암이 Purpose: It is well recognized that distinguishing benign papillary lesions from malignant papillary lesions on core needle biopsy may pose difficult diagnostic problems. This study was conducted to define the potential role of ultrasoundguided core biopsy for the diagnosis of papillary lesions of the breast. Methods: Twelve hundred and seventy nine women consecutively underwent 14-gauge core biopsy between January 2004 and December 2006. Of the 1,279 patients, 42 patients (3.2%) had papillary lesions of the breast on core needle biopsy. Of these 42 patients, 35 patients underwent surgical excision or sono-guided vacuum assisted excision. We compared the pathologic results of the excised specimens with the pathologic results on core needle biopsy. Results: Of the 35 patients, 23 patients underwent surgical excision and 12 patients underwent sono-guided vacuum assisted excision. Three patients with intraductal papilloma without atypism on the core needle biopsy were confirmed to have intraductal papilloma accompanied with atypism by the final pathology. All 4 patients with papillomatosis or intraductal papilloma with atypism at core needle biopsy were confirmed to have intraductal papilloma with atypism by the final pathology. There were no patients identified to have breast cancer. Conclusion: Our results revealed the accuracy of core needle biopsy for making the diagnosis of papillary lesions of the breast. Surgical excision may not always be necessary for papillary lesion of the breast that is diagnosed on core needle biopsy. Surgical excision is considered in patients with papillomatosis or papillary lesions with atypism seen on core needle biopsy.

4 citations


Journal ArticleDOI
TL;DR: In this paper, the authors give a characterisation of real hypersurfaces of type A, that is, a tube over a totally geodesic G2(ℂm+1) in complex two-plane Grassmannians.
Abstract: In this paper we give a characterisation of -invariant real hypersurfaces of type A; that is, a tube over a totally geodesic G2(ℂm+1) in complex two-plane Grassmannians G2(ℂm+2) or a ruled real hypersurface foliated by complex hypersurfaces which includes a maximal totally geodesic submanifold G2(ℂm+1) in G2(ℂm+2) in terms of η-parallel shape operator.

3 citations


Journal ArticleDOI
TL;DR: The sensitivity to chemotherapy, as determined by the HDRA, appears to be a good guide for selection in breast cancer patients and should be integrated into future research on the subject.
Abstract: Purpose: The behavior of invasive carcinomas in human can be very varied with different individual responses to chemotherapy. Individualization is crucial to the optimization of chemotherapy. Therefore, the prediction of a tumor’s sensitivity to anticancer agents has been the subject of intensive investigation. In order to investigate the pathobiology of breast cancer, it is necessary to maintain or recreate the characteristics of the three-dimensional architecture of the tissues in culture. In this study, we have evaluated the relationship between the Histoculture Drug Response Assay (HDRA) assessment and chemotherapy responses in breast cancer patients. Methods: Tumor specimens from 30 patients with breast cancer were evaluated using the HDRA. Tumor tissues were cultured on gelfoam sponge gel in 24-well plates, followed by treatment with a variety of chemotherapeutic agents. All treatments were conducted in triplicate. The sensitivity of a chemotherapy regimen was defined as a tumor inhibition rate (IR) in excess of 30%. Neoadjuvant or palliative chemotherapy for patients, using anthracycline or taxane, was conducted on the basis of the established protocols. The responses to treatments were compared with the results of the HDRA. Results: The mean IR for the combinations of doxorubicin and docetaxel and for FAC and AC were 48, 45, and 36%, respectively. The above partial rate of response to chemotherapy was 81.1%. The sensitivity and specificity of the HDRA assessment, with a 30% inhibition rate, were 81.5 and 66.7%, respectively. The positive and negative response prediction values were 91.7 and 44.4%, respectively. The responses to treatments and the results of the HDRA assessment were not correlated with the expressions of the hormonal receptor or c-erbB2. Conclusion: In cases in which the inhibition rate is in excess of 30%, the HDRA assessment yielded a high positive response prediction value. The sensitivity to chemotherapy, as determined by the HDRA, appears to be a good guide for selection in breast cancer patients. Thus the results presented herein should be integrated into future research on the subject.

3 citations


Journal ArticleDOI
TL;DR: The sensitivity to chemotherapy, as determined by the HDRA, appears to be a good guide for selection in breast cancer patients and should be integrated into future research on the subject.

Journal ArticleDOI
TL;DR: In this paper, the Hopf fibration of a real hypersurface M in complex space form M m(4e) has been studied and a complete classification of real hypersuri surfaces in M m (4e), which satisfy the above geometric facts is given.
Abstract: This paper consists of two parts. In the first, we find some geometric conditions derived from the local symmetry of the inverse image by the Hopf fibration of a real hypersurface M in complex space form M m(4e). In the second, we give a complete classification of real hypersurfaces in M m(4e) which satisfy the above geometric facts.

Journal Article
TL;DR: The expression of E-cadherin correlated with the diffuse type of cancer, according to the Lauren classification, but not with the survival rate, and there was no significant difference in the recurrence rate between the subgroups with and without an abnormalexpression of ECD.
Abstract: Purpose: E-cadherin (ECD) plays a pivotal role in integrating the normal tissue architecture and the suppression of cancer invasion, including stomach cancer. The epidemiology of stomach cancers is noticeably different according to the site of the index tumor, even though the stomach cancers all have similar gross shapes. In this study, the relation between the expression of ECD, along with the clinicopathologic parameters and recurrence or survival, were investigated for patients with gastric adenocarcinoma according to the tumor location. Methods: We examined formalin-fixed, paraffin-embedded archival tissues from 50 surgically resectable gastric adenocarcinomas, which were grouped by the index tumor site as follows: distal (antrum) versus proximal (mid and upper body). To elucidate the correlation between the ECD expression and the site of the stomach cancer with the other clinicopathologic factors, we examined the ECD tissue status via performing immunohistochemistry. To compare the rates of recurrence and survival among subgroups, the patients were followed up for an average of 42 months. Results: Among the 50 tumors examined, 28 (56%) tumors showed various degrees of a ECD expression. The gender, age, size, depth of invasion, lymph node metastasis, stage, lymphatic invasion and vascular invasion were not related with the ECD expression. The Lauren classification was correlated with the ECD expression in the mid and upper body stomach cancer, but not in the antral stomach cancer (P=0.042). The expression of ECD was not related with the survival rate (P=0.223). There was no significant difference in the recurrence rate between the subgroups with and without an abnormal expression of ECD (P=0.588). Conclusion: For the mid and upper body stomach cancer, the expression of E-cadherin correlated with the diffuse type of cancer, according to the Lauren classification, but not with the survival rate.