• 대한두경부종양학회지
• /
• 제20권1호
• /
• pp.3-6
• /
• 2004

Background and Objectives: Nodal metastasis is one of the prognostic factors in salivary gland cancer. The purpose of this study is to identify risk factors of nodal metastasis considered as a predictor of poor prognosis in patients with salivary gland cancer. Material and Methods: The authors retrospectively studied 82 patients with salivary gland cancer who underwent surgery from 1992 to 2002. We analyzed age, sex, tumor size, histologic type and 5-year survival rate to compare patients with and without nodal metastasis. Results: Mean age was 55.4 years, with a male-female ratio of 1 : 1.28. The overall 5-year survival rate was 85.5%. Among the 82 patients, 14 patients had nodal metastasis. There was no nodal metastasis in low grade malignancy. In patients without nodal metastasis, mean age was 52.5 years and the overall 5-year survival rate was 94.2%. In patients with nodal metastasis, mean age was 69.4 years and the overall 5-year survival rate was 42.9%. In patients with less advanced cancer (T1-T2 stage), the nodal metastasis was 7.5% and with advanced cancer (T3-T4 stage), 33.3%. Conclusion: Nodal metastasis significantly decreases survival in patients with salivary gland malignancy. High grade malignancy, large tumor size and old age are important risk factors of nodal metastasis. Nodal metastasis is more common in submandibular gland cancer compared with parotid gland cancer.

• Molecules and Cells
• /
• 제37권5호
• /
• pp.389-398
• /
• 2014

Siah acts as an E3 ubiquitin ligase that binds proteins destined for degradation. Extensive homology between siah and Drosophila Siah homologue (sina) suggests their important physiological roles during embryonic development. However, detailed functional studies of Siah in vertebrate development have not been carried out. Here we report that Siah2 specifically augments nodal related gene expression in marginal blastomeres at late blastula through early gastrula stages of zebrafish embryos. Siah2 dependent Nodal signaling augmentation is confirmed by cell-based reporter gene assays using 293T cells and 3TP-luciferase reporter plasmid. We also established a molecular hierarchy of Siah as a upstream regulator of FoxH1/Fast1 transcriptional factor in Nodal signaling. Elevated expression of nodal related genes by overexpression of Siah2 was enough to override the inhibitory effects of atv and lft2 on the Nodal signaling. In particular, E3 ubiquitin ligase activity of Siah2 is critical to limit the duration and/or magnitude of Nodal signaling. Additionally, since the embryos injected with Siah morpholinos mimicked the atv overexpression phenotype at least in part, our data support a model in which Siah is involved in mesendoderm patterning via modulating Nodal signaling.

• Nuclear Engineering and Technology
• /
• 제3권3호
• /
• pp.121-128
• /
• 1971

중성자속의 각분포를 unified modal-nodal 방법으로 전개하였다. 몇몇 표준 nodal 해석법이나 modal 해석법은 이 방법의 특수한 경우임을 밝혔다. 중성자의 발생과 산란이 등방성인 경우에 단일에너지 수송방정식을 modal-nodal moment 형으로 도출하여 고유치를 구하였다. 중성자가 생성되지 않는 매질 내에서의 역확산거리를 근사적으로 계산한 결과 표준방법으로 한 것보다 더 정화하였다.

• 상하수도학회지
• /
• 제16권6호
• /
• pp.726-732
• /
• 2002

Pressure drop could happen in the water distribution systems due to pipe breaks or maintenance. The pressure drop causes the water service shutdown and nodal water demands should be reduced in some areas. The conventional analysis method of water distribution systems can not consider the change of nodal water demands caused by these pressure drops. This study is to investigate the variation of nodal water demands according to the nodal water pressure and its effect on the analysis of water distribution systems. For these purpose, one real water service district was selected as a study area. As a result, nodal water demand patterns according to the water pressure could be suggested. Also, we could confirm that the suggested new analysis method for the water distribution systems which considering water pressure drops could be more reliable than the conventional method.

• Nuclear Engineering and Technology
• /
• 제56권3호
• /
• pp.772-784
• /
• 2024

The hexagonal nodal code RENUS has been enhanced to handle irregularly deformed hexagonal assemblies. The underlying RENUS methods involving triangle-based polynomial expansion nodal (T-PEN) and corner point balance (CPB) were extended in a way to use line and surface integrals of polynomials in a deformed hexagonal geometry. The nodal calculation is accelerated by the coarse mesh finite difference (CMFD) formulation extended to unstructured geometry. The accuracy of the unstructured nodal solution was evaluated for a group of 2D SFR core problems in which the assembly corner points are arbitrarily displaced. The RENUS results for the change in nuclear characteristics resulting from fuel deformation were compared with those of the reference McCARD Monte Carlo code. It turned out that the two solutions agree within 18 pcm in reactivity change and 0.46% in assembly power distribution change. These results demonstrate that the proposed unstructured nodal method can accurately model heterogeneous thermal expansion in hexagonal fueled cores.

• 한국에너지공학회:학술대회논문집
• /
• 한국에너지공학회 2000년도 추계 학술발표회 논문집
• /
• pp.115-120
• /
• 2000

The analysis of flux distribution under stead-state in large power reactors with assymetry reactivity insertions requires the use of three-dimensional diffusion calculations. For the purpose, consistently formulated modern nodal methods based on higher order interface techniques have become popular tools for flux distributions in large commercial nuclear reactors. Among the earlier developments, the nodal Green's function method obtains its nodal interface equation from the transverse-integrated integral diffusion equation using a finite-medium Green's function. In this method, the outgoing current from a node surface is formulated as a response of the incoming currents and the spatially integrated neutron source within the same node. The well-known nodal expansion method is also based on an interface partial current formulation. Nodal methods high-level interface variables, i.e., interface net current and flux, may be more computationally efficient than the nodal Green's function method because they have one fewer unknown per interface. The Analytic Nodal Method(ANM), which can be classified as an interface net current technique and, was faster in solving some standard benchmark problems than the other two methods.(omitted)

• 대한기계학회논문집A
• /
• 제29권4호
• /
• pp.534-539
• /
• 2005

Nodal displacements are referred to the initial configuration in the total Lagrangian formulation and to the last converged configuration in the updated Lagrangian furmulation. This research proposes a relative nodal displacement method to represent the position and orientation for a node in truss structures. Since the proposed method measures the relative nodal displacements relative to its adjacent nodal reference frame, they are still small for a truss structure undergoing large deformations for the small size elements. As a consequence, element formulations developed under the small deformation assumption are still valid for structures undergoing large deformations, which significantly simplifies the equations of equilibrium. A structural system is represented by a graph to systematically develop the governing equations of equilibrium for general systems. A node and an element are represented by a node and an edge in graph representation, respectively. Closed loops are opened to form a spanning tree by cutting edges. Two computational sequences are defined in the graph representation. One is the forward path sequence that is used to recover the Cartesian nodal displacements from relative nodal displacement sand traverses a graph from the base node towards the terminal nodes. The other is the backward path sequence that is used to recover the nodal forces in the relative coordinate system from the known nodal forces in the absolute coordinate system and traverses from the terminal nodes towards the base node. One open loop and one closed loop structure undergoing large deformations are analyzed to demonstrate the efficiency and validity of the proposed method.

• Applied Microscopy
• /
• 제28권1호
• /
• pp.1-19
• /
• 1998

Ultrastructural study of the development of the atrioventricular (AV) node was studied by electron microscopy in human fetus ranging from 30 mm to 260 mm crown rump length, and compared with human adult. By 30 mm fetus, the right AV nodal primordium was located below the attachment of the right venous valve. The left AV nodal primordium was observed below the attachment of septum primum. The cytoplasm of the nodal primordia contained few mitochondria, and myofibrils. These cells were apposed to each other with occasional desmosomes. In 40 mm fetus, the AV node cells were poorly organized myofibrils, while working myocardial cells were well organized myofibrils with sarcomere. At 70 mm fetus, intercalated discs were developed in the working myocardial cells. At 100 mm fetus, the nodal cells contained a relatively clear cytoplasm with a few groups of myofibrils and mitochondria. By $140\sim200$ mm fetuses, the nodal cells were an increasing number of myofibrils and mitochondria and these were scattered throughout the cytoplasm. At 260 mm fetus, the nodal cells were small and contained a clear cytoplasm with sparse and poorly organized myofibrils and mitochondria. All major ultrastructural features which characterize the adult AV nodal cells were found in this stage. The working myocardial cells were larger and had a more compact cytoarchitecture than nodal cells. Zonula adherens or fasciae adherens type junction were not found between nodal cells, but they frequently observed between nodal and working myocardial cells.

• 대한수학회지
• /
• 제57권4호
• /
• pp.809-823
• /
• 2020

In this article, we study the deformation theory of locally free sheaves and Hitchin pairs over a nodal curve. As a special case, the infinitesimal deformation of these objects gives the tangent space of the corresponding moduli spaces, which can be used to calculate the dimension of the corresponding moduli space. The deformation theory of locally free sheaves and Hitchin pairs over a nodal curve can be interpreted as the deformation theory of generalized parabolic bundles and generalized parabolic Hitchin pairs over the normalization of the nodal curve, respectively. This interpretation is given by the correspondence between locally free sheaves over a nodal curve and generalized parabolic bundles over its normalization.

• Interaction and multiscale mechanics
• /
• 제6권2호
• /
• pp.107-125
• /
• 2013

A strain smoothing meshfree formulation with stabilized conforming nodal integration is presented for modeling the consolidation process in saturated porous media. In the present method, nodal strain smoothing is consistently introduced into the meshfree approximation of strain and pore pressure gradient variables associated with the saturated porous media. Meanwhile, in order to achieve a consistent numerical implementation, a smoothing approximation of the meshfree shape function within a nodal representative domain is also proposed in the stiffness construction. The resulting discrete system of equations is all expressed in smoothed nodal measures that are very efficient for numerical evaluation. Subsequently the space-time fully discrete equations are further established by the generalized trapezoidal rule for time integration. The effectiveness of the proposed meshfree consolidation analysis method is systematically illustrated by several benchmark problems.