Showing papers by "Young Jin Suh published in 2011"
TL;DR: For Hopf real hypersurfaces in complex two-plane Grassmannians G2(ℂm+2) with 𝔇⊥-parallel structure Jacobi operator, where &# x 1d507, ℂ m+2 = Span {ξ 1, ξ 2, ν 3, ǫ, Ã, Ã, Á, À, Þ, Ò, Ð, Ñ, Æ, Ô, Ú, Ó, Ø
Abstract: In this paper we give some non-existence theorems for Hopf real hypersurfaces in complex two-plane Grassmannians G2(ℂm+2) with 𝔇⊥-parallel structure Jacobi operator, where 𝔇⊥ = Span {ξ1, ξ2, ξ3}.
37 citations
TL;DR: In this paper, the authors identify the clinicopathological characteristics and prognostic value of p53 overexpression in breast cancer patients treated with a modified radical mastectomy and show that p53 over-expression is correlated with breast cancer-specific death rates and adverse prognostic factors.
Abstract: Objective: The purpose of this study was to identify the clinicopathological characteristics and prognostic value of p53 overexpression in breast cancer patients treated with a modified radical mastectomy. Methods: The medical records of 197 patients who had undergone modified radical mastectomy between January 1991 and December 2008 were reviewed retrospectively. Breast cancer subtype and p53 overexpression were investigated using immunohistochemistry and/ or fluorescent in situ hybridization analysis of surgical specimens. Results: The median follow-up after the modified radical mastectomy was 56.1 months (range, 14.7–232.7). The median age was 47 years (range, 31–72). p53 overexpression was noted in 73 patients (37.1%). Breast cancer-specific death rate (P ¼ 0.011), cancer progression (P ¼ 0.024), distant metastasis (P ¼ 0.015), hormone receptor negativity (P , 0.001) and human epidermal growth factor receptor 2 positivity (P ¼ 0.017) were detected more frequently in patients with p53 overexpression. The overall survival rates were significantly lower in the p53-overexpression group than in the non-p53-overexpression group (P ¼ 0.021, log-rank test). In the multivariate analysis, p53 overexpression showed the strongest prognostic significance in patients aged ,50 years (P ¼ 0.039) and with the triple-negative subtype (P ¼ 0.023). Conclusions: p53 overexpression correlated with breast cancer-specific death rates and adverse prognostic factors in patients treated with modified radical mastectomy. p53 overexpression might be a more reliable prognosticator in patients aged ,50 years and with the triple-negative subtype. More effective systemic treatments might be warranted for these patients exhibiting p53 overexpression. Further validation is required to make more definite conclusions.
27 citations
TL;DR: In this article, a non-existence theorem for Hopf hypersurfaces M in complex two-plane Grassmannians whose normal Jacobi operator is parallel on the distribution F defined by, where [] = Span{}, = Span {,,, } and,.
Abstract: In this paper we give a non-existence theorem for Hopf hypersurfaces M in complex two-plane Grassmannians whose normal Jacobi operator is parallel on the distribution F defined by , where [] = Span{}, = Span {, , } and , .
19 citations
TL;DR: It is suggested that careful observation of a laparoscopic procedure, such as acting as the scope operator for a certain amount of time, may help in shortening the LC of the actual procedure.
Abstract: Background: We aimed to evaluate the learning curve (LC) for laparoscopic right-sided colon cancer surgery (LRCCS) by comparing the results between two surgeons (first-generation colorectal surgeon versus laparoscopically trained surgeon). Methods: The study was a retrospective analysis that evaluated 117 consecutive LRCCSs performed by two surgeons, the first-generation surgeon (Surgeon A) and laparoscopically trained surgeon (Surgeon B), from April 1995 to August 2006. Patients were divided into two groups; patients included in groups I and II received LRCCSs from surgeons A and B, respectively. Results: The moving average method revealed that the operation times of surgeons A and B began to shorten after the 9th case. The cumulative sum (CUSUM) analysis of group I data showed that the 24th case was the peak point of conversion. The 35th case was the peak for intraoperative complications, and the 17th case was the peak for postoperative complications. There was only one case of conversion in gr...
18 citations
15 citations
TL;DR: The Bethesda system seemed to provide stricter boundaries for the atypical cytology and to aid in reducing the rates thereof, which in turn may permit that more limited cases are allotted to ultrasonographic decision making.
Abstract: Purpose: For the atypical cases of fine needle aspiration (FNA) cytology of thyroid nodules, ultrasonographic findings are a primary guideline for the surgical treatment. However, they have the intrinsic risk of overtreatment, as well. In this study we examined whether the Bethesda system could provide a real effect on the diagnostic rate of atypical cytology, and thereby reduce the number of cases diagnosed as atypical from FNA cytology. Methods: We reviewed 166 cases diagnosed as atypical by FNA cytology at this institute between the years 2005 to 2010. We classified these cases on the basis of ultrasonographic and cytological findings and compared them with the histological results. Results: Ultrasonographically, findings suspicious for malignancy and indeterminate were associated with 83.7% and 47.2% of malignancy rates, respectively. Cytopathologically, the malignancy rates varied according to the main cytological features and the highest malignancy rate was 77.3%. Based on the Bethesda system, 39.2% of the cases diagnosed as atypical could be grouped into the category of suspicious for malignancy and yielded a malignancy rate of 76.9%. Conclusion: Although ultrasonography provides an excellent guideline for the surgical treatment of atypical cases, it also showed considerable risk of overtreatment. The Bethesda system did not offer definitive effects on the rate of atypical cytology, but this system seemed to provide stricter boundaries for the atypical cytology and to aid in reducing the rates thereof. This in turn may permit that more limited cases are allotted to ultrasonographic decision making.
14 citations
01 Jan 2011
TL;DR: In this article, a new proof of a theorem concerned with conformally symmetric Riemannian manifolds due to Roter and Derdzin- sky (8), (9) and Miyazawa (15) was given.
Abstract: In order to give a new proof of a theorem concerned with conformally symmetric Riemannian manifolds due to Roter and Derdzin- sky (8), (9) and Miyazawa (15), we have adopted the technique used in a theorem about conformally recurrent manifolds with harmonic conformal curvature tensor in (3). In this paper, we also present a new proof of a suc- cessive reflned version of a theorem about conformally recurrent manifolds with harmonic conformal curvature tensor. Moreover, as an extension of theorems mentioned above we prove some theorems related to quasi con- formally recurrent Riemannian manifolds with harmonic quasi conformal curvature tensor.
13 citations
TL;DR: In this paper, the authors prove the non-existence of real hypersurfaces in complex two-plane Grassmannians whose normal Jacobi operator is of Codazzi type.
Abstract: We prove the non-existence of real hypersurfaces in complex two-plane Grassmannians whose normal Jacobi operator is of Codazzi type.
9 citations
TL;DR: In this article, the generalized Tanaka-Webster connection for hypersurfaces in complex two-plane Grassmannians G2(Cm+2) was introduced and a non-existence theorem for Hopf hypersurface in G2 (Cm + 2) with parallel shape operator in this connection was proved.
Abstract: We introduce the notion of generalized Tanaka-Webster connection for hypersurfaces in complex two-plane Grassmannians G2(Cm+2) and give a non-existence theorem for Hopf hypersurfaces in G2(Cm+2) with parallel shape operator in this connection.
8 citations
TL;DR: Paclitaxel and lovastatin were cytotoxic in two ATC cell lines and increased apoptosis in 8505C cells and in BHT-101 cells, however, the combination of drugs resulted in antagonism that affected both the cytotoxicity of the compounds and the apoptosis of 8505 C cells.
Abstract: Background: Anaplastic thyroid carcinoma (ATC) is the most aggressive type of thyroid carcinoma. The purpose of this study was to evaluate the combined cytotoxic effects of paclitaxel and lovastatin in ATC cell lines. Methods: ATC cells were treated with paclitaxel and lovastatin, separately or together, and the cytotoxicity of the compounds was determined by quantifying cell viability and apoptosis. We conducted an isobologram analysis to investigate the combined effect of the two drugs. Results: In 8505C cells, cellular viability was inhibited by lovastatin and paclitaxel in a concentration-dependent manner (p = 0.002 and p = 0.020, respectively). The IC50 of lovastatin was 3.53 μM and that of paclitaxel was 5.98 nM. In BHT-101 cells, cellular viability was also inhibited in a concentration-dependent manner by lovastatin and paclitaxel (p = 0.020 and p = 0.032, respectively). The IC50 of lovastatin was 17.13 μM and that of paclitaxel was 35.26 nM. In 8505C cells, paclitaxel and lovastatin alone induced ...
8 citations
TL;DR: The comedo subtype of ductal carcinoma in situ, a high histologic grade, the presence of necrosis and the Van Nuys group 3 were significant predictors of axillary lymph node metastasis in patients with T1mi breast cancer.
Abstract: Objective: This study was designed to evaluate the rate and the predictors of axillary lymph node metastasis in patients with T1mi breast cancer. Methods: We analyzed 62 cases of ductal carcinoma in situ with microinvasion, and the pathology records and treatment charts were retrospectively reviewed for information on the patient and tumor characteristics. All the included patients underwent breast conserving surgery and 48 patients underwent axillary lymph node dissection. Results: The incidence of axillary involvement was 8.3%. Comedo ductal carcinoma in situ (P ¼ 0.031), histologic grade 3 (P ¼ 0.025), the presence of necrosis (P ¼ 0.007) and Van Nuys group 3 (P ¼ 0.025) were significant predictors of axillary involvement on the statistical analysis. Axillary dissection was significantly associated with the occurrence of arm lymphedema (P ¼ 0.030). Conclusions: A significant rate of axillary metastases occurred in the patients with T1mi breast carcinoma in this study. The comedo subtype of ductal carcinoma in situ, a high histologic grade, the presence of necrosis and the Van Nuys group 3 were significant predictors of axillary lymph node metastasis in patients with T1mi breast cancer. Thus, the patients with T1mi breast disease are indicated to a careful evaluation of axillary lymph node metastasis, if they have the earlier-mentioned unfavorable factors.
TL;DR: For Hopf hypersurfaces in the complex two-plane Grassmannian G2(C) with Lie parallel normal Jacobi operator R̄N and totally geodesic D and D ⊥ components of the Reeb flow, the authors gave some non-existence theorems.
Abstract: In this paper we give some non-existence theorems for Hopf hypersurfaces in the complex two-plane Grassmannian G2(C) with Lie parallel normal Jacobi operator R̄N and totally geodesic D and D ⊥ components of the Reeb flow. 0. Introduction The Jacobi fields along geodesics of a given Riemannian manifold (M̄, ḡ) play an important role in the study of differential geometry. It satisfies a very well-known differential equation. This classical differential equation naturally inspires the so-called Jacobi operators. That is, if R̄ is the curvature operator of M̄ and X is any vector field tangent to M̄ , the Jacobi operator with respect to X at x ∈ M̄ , R̄X ∈ End(TxM̄), is defined as R̄X(Y )(x) = (R̄(Y,X)X)(x) for all Y ∈ TxM̄ , being a self-adjoint endomorphism of the tangent bundle TM̄ of M̄ . Clearly, each vector field X tangent to M̄ provides a Jacobi operator with respect to X (See [7] and [9]). If the structure vector field ξ = −JN of a real hypersurface M in complex projective space Pn(C) is invariant under the shape operator, ξ is said to be Hopf, where J denotes a Kähler structure of Pn(C), and N is a unit normal vector field of M in Pn(C). In the quaternionic projective space HP Pérez and Suh [10] classified the real hypersurfaces in HP with D⊥-parallel curvature tensor ∇ξνR = 0 for ν = 1, 2, 3, where R denotes the curvature tensor of M in HP and D⊥ is a distribution defined by D⊥ = Span {ξ1, ξ2, ξ3}. In this case they are congruent to a tube of radius π4 over a totally geodesic quaternionic submanifold HP k in HP, 2 ≤ k ≤ m− 2. Received September 22, 2009; Revised July 2, 2010. 2010 Mathematics Subject Classification. Primary 53C40; Secondary 53C15.
TL;DR: In this article, the authors prove the non-existence of Hopf real hypersurfaces in complex two-plane Grassmannians whose Jacobi operators corresponding to the directions in the distribution D are of Codazzi type if they satisfy a further condition.
Abstract: We prove the non-existence of Hopf real hypersurfaces in complex two-plane Grassmannians whose Jacobi operators corresponding to the directions in the distribution D are of Codazzi type if they satisfy a further condition. We obtain that that they must be either of type (A) or of type (B) (see [1]), but no one of these satisfies our condition. As a consequence, we obtain the non-existence of Hopf real hypersurfaces in such ambient spaces whose Jacobi operators corresponding to D -directions are parallel with the same further condition.
TL;DR: In this article, the authors give a pinching condition for compact minimal hypersurfaces in complex two-plane Grassmannians G 2 (ℂm+2) in terms of sectional curvature and the squared norm of the shape operator.
Abstract: We give a pinching condition for compact minimal hypersurfaces in complex two-plane Grassmannians G
2(ℂm+2) in terms of sectional curvature and the squared norm of the shape operator.
TL;DR: In this paper, real hypersurfaces in complex projective space whose structure Jacobi operator satisfies two conditions at the same time were classified, i.e., the Jacobi operators satisfy two conditions simultaneously.
Abstract: We classify real hypersurfaces in complex projective space whose structure Jacobi operator satisfies two conditions at the same time.
01 Jan 2011
TL;DR: In this paper, it was shown that Hopf real hypersurfaces in complex two-plane Grassmannians whose Jacobi operators corresponding to the directions in the distribution are D-parallel are not Hopf-real hypersurface.
Abstract: We prove the non-existence of Hopf real hypersurfaces in complex two-plane Grassmannians whose Jacobi operators corresponding to the directions in the distribution D ? are D-parallel if they satisfy a further condition.