• Journal of the Korean Mathematical Society
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• v.42 no.6
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• pp.1169-1186
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• 2005

We study the properties of the transversal Killing and twistor spinors for a Riemannian foliation with a transverse spin structure. And we investigate the relations between them. As an application, we give a new lower bound for the eigenvalues of the basic Dirac operator by using the transversal twistor operator.

• Bulletin of the Korean Mathematical Society
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• v.57 no.5
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• pp.1299-1306
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• 2020

An almost contact metric manifold is called a quasi contact metric manifold if the corresponding almost Hermitian cone is a quasi Kähler manifold, which was introduced by Y. Tashiro [9] as a contact O*-manifold. In this paper, we show that a quasi contact metric manifold with Killing characteristic vector field is a K-contact manifold. This provides an extension of the definition of K-contact manifold.

• Bulletin of the Korean Mathematical Society
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• v.49 no.6
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• pp.1163-1178
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• 2012

In this paper, we study the geometry of Einstein half lightlike submanifolds M of a semi-Riemannian space form $\bar{M}(c)$ subject to the conditions: (a) M is screen conformal, and (b) the coscreen distribution of M is a conformal Killing one. The main result is a classification theorem for screen conformal Einstein half lightlike submanifolds of a Lorentzian space form with a conformal Killing coscreen distribution.

• Journal of the Korean Mathematical Society
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• v.46 no.6
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• pp.1193-1206
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• 2009

C. Guenther studied the stability of DeTurck flows by using maximal regularity theory and center manifolds, but these arguments can not solve the stability of Ricci flows because the Ricci flow equation is not strictly parabolic. Recognizing this deficiency, the present paper considers and obtains the stability of Ricci flows, and of quasi-Ricci flows in view of some Killing conditions.

• Honam Mathematical Journal
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• v.41 no.2
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• pp.329-342
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• 2019

In this paper, we give a geometric approach to Killing magnetic flux surfaces in Euclidean 3-space and solve the differential equations which expressed the mentioned surfaces. Furthermore we give some examples and draw their pictures by using the programme Mathematica.

• Journal of fish pathology
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• v.28 no.3
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• pp.171-174
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• 2015

Previously, we had reported that some Miamiensis avidus, a major pathogen of scuticociliatosis in cultured olive flounder, strongly agglutinated by flounder immune sera could escape from the agglutinated mass within a few hours. In the present study, we observed that M. avidus not only escaped from the agglutinated mass but also conducted division(s) before shedding its old covering. Furthermore, ciliates that survived the antibody-dependent complement killing (ADCK) assay were not killed even when re-exposed to a freshly prepared ADCK assay. This result suggests that the liberated ciliates from the ADCK assay might change not only their i-antigen types but also the epitopes of major surface antigens, which debilitate antibody-mediated complement killing ability.

• Journal of fish pathology
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• v.15 no.2
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• pp.77-82
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• 2002

Effects of stress-induced suppression of humoral immunity on scuticociliate killing activity of olive flounder plasma were investigated. Changes in glucose level. alternative complement activity and Iysozyme activity of plasma by handling stress were analysed in relation to in vitri parasiticidal activity of plasma. The plasma glucose level was about two times higher in fish after a handling stress than in control fish. Plasma lysozyme activity and natural haemolytic activity were decreased in suessed fish.The scuticociliate killing activity of plasma was significantly lower in stressed fish than in non-stressed control fish. The present results indicated that stress-induced immunodepression could be a cause of scuticociliatosis occurrence in olive flounder.

• Journal of the Korean Mathematical Society
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• v.59 no.2
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• pp.255-278
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• 2022

In this paper, first we introduce a new notion of generalized Killing structure Jacobi operator for a real hypersurface M in complex hyperbolic two-plane Grassmannians SU_2,m/S (U₂·U_m). Next we prove that there does not exist a Hopf real hypersurface in complex hyperbolic two-plane Grassmannians SU_2,m/S (U₂·U_m) with generalized Killing structure Jacobi operator.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.852-858
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• 1998

We have isolated a bacterial strain that tends to kill P. micans from the mixed culture of p. minns plus seawater filtrate (poresize, 0.8 $\mu$m) collected at Masan bay in July 1996, in which the mixed culture grown in the f/2 medium. According to the experimental results of the isolated bacterium such as fatty acids analysis, morphological and biochemical characteristic tests, the strain was supposed to be a Pseudomonas and then it was named as Pseudomonas sp. LG-2. The killing effect of Pseudomonas sp. LG-2 against P. micans was proportionally increased with the concentrations of culture filtrate (pore size, 0.8 $\mu$m) is well as with the number of bacterium inoculated. In the mixed culture inoculated with $1.3\times10^6$ cells/ml of Pseudomonas sp. LG-2, the number of P. micans (2,000 cells/ml) was gradually decreased and then killed below 100 cells/ml within 7 days. In addition, the culture filtrate with $30\%$ of final concentration revealed a significant killing effect against P. micans around 3 days after culture. In the relationship between killing effects and growth stage of Pseudomonas sp. LG-2, the culture filtrate at lag phase has little effects on P. micans. In constant, the culture filtrate at mid-log phase showed the killing effect by decreasing P. micans to 112 in number within 5 days. In particular, the culture filtrate at stationary phase showed a significant killing effect against P. micans in which the majority of it was killed after 3 day culture. The species specificity of killing effects of Pseudomonas sp. LG-2 against 5 species of dinoflagellate was only found in P. micans and Scrippsiella trochoidea.

• Animal cells and systems
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• v.8 no.2
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• pp.125-133
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• 2004

We have extended our previous work that cross-linking CD4 molecules using specific MAb induced antigen nonspecific, MHC unrestricted killing of virally infected target cells by CD$4^+$We have extended our previous work that cross-linking CD$4^+$ molecules using specific MAb induced antigen nonspecific, MHC unrestricted killing of virally infected target cells by CD$4^+$ T cells. The killing activity of antibody activated CD$4^+$T cells was completely blocked by herbimycin A, a protein tyrosine kinase (PTK) inhibitor, but not by bisindolylamaleimide, a protein kinase C (PKC) inhibitor. Herbimycin A treated human or bovine peripheral blood CD$4^+$T cells lacked PTK activity and failed to kill virally infected target cells even after cross-linking of CD4 molecules. The CD$4^+$cross-linking failed to induce effector cell proliferation or the transcription of TNF${\beta}$ Upregulation of TNF${\beta}$ was induced by incubating the antibody activated effector cells with BHV-1 infected D17 target cells for 10 h. Anti-TNF${\beta}$ antibody partially abolished (13-44%) the direct effector cell-mediated antiviral cytotoxicity. However, this antibody neutralized 70 to 100% of antiviral activity of effector and target cell culture supernatants against BHV-1 infected D17 cells. The inhibition level of the antiviral activity by the antibody was dependent on the effector and target cell ratio. These results support the hypothesis that increased p$56^ICK enzyme activity in effector cells transduces a signal critical for effector cell recognition of viral glycoproteins expressed on the target cells. Following target cell recognition, lytic cytokines known to participate in target cell killing were produced. A better understanding of the killing activity displayed by CD$4^+$T lymphocytes following surface receptor cross-linking will provide insight into the mechanisms of cytotoxic activity directed toward virally-infected cells.T cells. The killing activity of antibody activated CD$4^+$T cells was completely blocked by herbimycin A, a protein tyrosine kinase (PTK) inhibitor, but not by bisindolylamaleimide, a protein kinase C (PKC) inhibitor. Herbimycin A treated human or bovine peripheral blood CD4T cells lacked PTK activity and failed to kill virally infected target cells even after cross-linking of CD4molecules. The CD4 cross-linking failed to induce effector cell proliferation or the transcription of TNF$\beta$. Upregulation of TNF$\beta$ was induced by incubating the antibody activated effector cells with BHV-1 infected D17 target cells for 10 h. Anti-TNF$\beta$ antibody partially abolished (13-44%) the direct effector cell-mediated antiviral cytotoxicity. However, this antibody neutralized 70 to 100% of antiviral activity of effector and target cell culture supernatants against BHV-1 infected D17 cells. The inhibition level of the antiviral activity by the antibody was dependent on the effector and target cell ratio. These results support the hypothesis that increased $56^ICK enzyme activity in effector cells transduces a signal critical for effector cell recognition of viral glycoproteins expressed on the target cells. Following target cell recognition, lytic cytokines known to participate in target cell killing were produced. A better understanding of the killing activity displayed by CD$4^+$T lymphocytes following surface receptor cross-linking will provide insight into the mechanisms of cytotoxic activity directed toward virally-infected cells.