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Structural Optimization of a Multi-Physics Problem Considering Thermal and Magnetic Effects
Soonok Park,Jeonghoon Yoo IEEE 2012 IEEE transactions on magnetics Vol.48 No.11
<P>Most researches regarding structural design of electromagnetic systems have been focused on a single physical phenomenon such as magnetic, electric or thermal effect. However, analysis and design of the multi-physics phenomenon is coming to the fore related with the actuator system targeting on the small size and high performance. Two or more physics phenomena are taken into account in a multi-physics system and the multi-physics analysis is performed using the governing equation in the formulation of a partial differential equation. Accordingly, in actuator design, it is generally hard to predict an optimal shape accurately considering both the magnetic and the thermal effect simultaneously. The objective of this research is set to establish a simultaneous/parallel design process for a multi-physics problem combining magnetic and thermal effects by employing the adoptive weighting factor while the previous work mostly suggests a sequential design process. The proposed method has been applied to yoke shape design of a C-core type magnetic actuator for minimizing the heat transfer effect as well as maximizing the actuating force. The topology optimization scheme based on the density approach is employed to obtain the optimal shape.</P>
Optimal Shape Design of the Perpendicular Magnetic Recording Head
Soonok Park,Jeonghoon Yoo,Jae Seok Choi IEEE 2009 IEEE transactions on magnetics Vol.45 No.5
<P>It is necessary to develop a perpendicular magnetic recording head for the high magnetic field density of the recording region with small magnetic field leakage. This work suggests a topology design of the perpendicular magnetic recording head based on the density method. In order to determine the shape of a magnetic head with the return yoke, the topology optimization method is combined with the finite element method. Obtained results are also compared with results of the previous studies.</P>
Simultaneous Optimal Design of the Yoke and the Coil in the Perpendicular Magnetic Recording Head
Soonok Park,Jeonghoon Yoo,Jae Seok Choi IEEE 2009 IEEE transactions on magnetics Vol.45 No.10
<P>The optimal design of magnetic recording head with the coil is an important issue for the high magnetic recording density with small magnetic field leakage. This work proposes a topology design of the yoke and the coil in the perpendicular magnetic recording (PMR) head based on the density method. In order to determine the shape of the coil as well as the yoke in the head, the topology optimization method combined with the finite-element method (FEM) is used. The numerical result shows significant improvement, that is, the recording flux increasing in the magnetic recording region with the leakage reduction in the adjacent area. Results are verified through the commercial package simulation using Maxwell.</P>
( Soonok Kim ),( Yun Sung Cho ),( Jong Bhak ),( Stephen J. O`brian ),( Joo-hong Yeo ) 생화학분자생물학회(구 한국생화학분자생물학회) 2017 BMB Reports Vol.50 No.1
Recent advances in genome sequencing technologies have enabled humans to generate and investigate the genomes of wild species. This includes the big cat family, such as tigers, lions, and leopards. Adding the first high quality leopard genome, we have performed an in-depth comparative analysis to identify the genomic signatures in the evolution of felid to become the top predators on land. Our study focused on how the carnivore genomes, as compared to the omnivore or herbivore genomes, shared evolutionary adaptations in genes associated with nutrient metabolism, muscle strength, agility, and other traits responsible for hunting and meat digestion. We found genetic evidence that genomes represent what animals eat through modifying genes. Highly conserved genetically relevant regions were discovered in genomes at the family level. Also, the Felidae family genomes exhibited low levels of genetic diversity associated with decreased population sizes, presumably because of their strict diet, suggesting their vulnerability and critical conservation status. Our findings can be used for human health enhancement, since we share the same genes as cats with some variation. This is an example how wildlife genomes can be a critical resource for human evolution, providing key genetic marker information for disease treatment. [BMB Reports 2017; 50(1): 3-4]
Kim, Soonok,Hu, Jinnan,Oh, Yeonyee,Park, Jongsun,Choi, Jinhee,Lee, Yong-Hwan,Dean, Ralph A.,Mitchell, Thomas K. Public Library of Science 2010 PLoS pathogens Vol.6 No.5
<▼1><P>Significant progress has been made in defining the central signaling networks in many organisms, but collectively we know little about the downstream targets of these networks and the genes they regulate. To reconstruct the regulatory circuit of calcineurin signal transduction via <I>MoCRZ1</I>, a <I>Magnaporthe oryzae</I> C2H2 transcription factor activated by calcineurin dephosphorylation, we used a combined approach of chromatin immunoprecipitation - chip (ChIP-chip), coupled with microarray expression studies. One hundred forty genes were identified as being both a direct target of MoCRZ1 and having expression concurrently differentially regulated in a calcium/calcineurin/MoCRZ1 dependent manner. Highly represented were genes involved in calcium signaling, small molecule transport, ion homeostasis, cell wall synthesis/maintenance, and fungal virulence. Of particular note, genes involved in vesicle mediated secretion necessary for establishing host associations, were also found. <I>MoCRZ1</I> itself was a target, suggesting a previously unreported autoregulation control point. The data also implicated a previously unreported feedback regulation mechanism of calcineurin activity. We propose that calcium/calcineurin regulated signal transduction circuits controlling development and pathogenicity manifest through multiple layers of regulation. We present results from the ChIP-chip and expression analysis along with a refined model of calcium/calcineurin signaling in this important plant pathogen.</P></▼1><▼2><P><B>Author Summary</B></P><P>All organisms have the innate ability to perceive their environment and respond to it, largely through controlling gene expression. Tailored specificity of a response is primarily achieved through signal cascades involving unique receptors, downstream transcription factors (proteins that bind to DNA to regulate gene expression), and the genes these transcription factors regulate. For fungal plant pathogens, signal transduction cascades are involved in perception of hosts, transgression of physical barriers, suppression or elicitation of host defenses, <I>in vivo</I> nutrient acquisition, and completion of their life cycle. We know that the Ca<SUP>2+</SUP>/calcineurin signaling pathway is a central conduit regulating these aspects of the life cycle for fungal pathogens of plants and animals. In this study, we used advanced ChIP-chip and microarray gene expression technologies to identify the genes that the Ca<SUP>2+</SUP>/calcineurin responsive transcription factor MoCRZ1 directly binds to and regulates the expression of. Our findings show conservations and divergence in this pathway within the fungal kingdom. It also identifies points of control in the pathway that were previously unidentified. Most importantly, this study implicates this pathway in the establishment of host associations and virulence for the causal agent of rice blast disease, <I>Magnaporthe oryzae</I>, the most important disease of rice worldwide.</P></▼2>
Kim, Soonok,Ahn, Il‐,Pyung,Rho, Hee‐,Sool,Lee, Yong‐,Hwan Blackwell Science Ltd 2005 Molecular microbiology Vol.57 No.5
<P><B>Summary</B></P><P>Fungal hydrophobins are implicated in cell morphogenesis and pathogenicity in several plant pathogenic fungi including the rice blast fungus <I>Magnaporthe grisea</I>. A cDNA clone encoding a hydrophobin (magnaporin, <I>MHP1</I>) was isolated from a cDNA library constructed from rice leaves infected by <I>M. grisea</I>. The <I>MHP1</I> codes for a typical fungal hydrophobin of 102 amino acids containing eight cysteine residues spaced in a conserved pattern. Hydropathy analysis of amino acids revealed that MHP1 belongs to the class II group of hydrophobins. The amino acid sequence of MHP1 exhibited about 20% similarity to MPG1, an <I>M. grisea</I> class I hydrophobin. Expression of <I>MHP1</I> was highly induced during plant colonization and conidiation, but could hardly be detected during mycelial growth. Transformants in which <I>MHP1</I> was inactivated by targeted gene replacement showed a detergent wettable phenotype, but were not altered in wettability with water. <I>mhp1</I> mutants also exhibited pleiotropic effects on fungal morphogenesis, including reduction in conidiation, conidial germination, appressorium development and infectious growth in host cells. Furthermore, conidia of <I>mhp1</I> mutants were defective in their cellular organelles and rapidly lose viability. As a result, <I>mhp1</I> mutants exhibited a reduced ability to infect and colonize a susceptible rice cultivar. These phenotypes were recovered by re‐introduction of an intact copy of <I>MHP1</I>. Taken together, these results indicate that <I>MHP1</I> has essential roles in surface hydrophobicity and infection‐related fungal development, and is required for pathogenicity of <I>M. grisea</I>.</P>