• Animal cells and systems
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• v.6 no.2
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• pp.181-181
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• 2002

Nek2 is a mammalian protein kinase that is structurally homologous to NIMA, a mitotic regulator in Aspergillus nidulans. We recently observed that the Nek2 protein was localized in multiple sites within a cell in a cell cycle state-specific manner. This suggests that Ndk2 is involved in diverse cellular functions during the cell cycle progression. To have a better understanding on cellular functions in which Nek2 participates, we carried out yeast two-hybrid screening and isolated six candidate clones whose products interact with Nek2. Most of Nek2-interacting proteins (NIPs) appear cytoplasmic, suggesting that Nek2 is involved in cellular functions in cytoplasm. Further experiments are under progress to confirm their interactions with Nek2 and to understand their biological significance.

• Animal cells and systems
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• v.10 no.4
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• pp.237-241
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• 2006

Chemotactic behavior is essential for the survival of animals. However, the mechanism by which animals carry out chemotaxis is poorly understood. To explore the biochemical events underlying chemotaxis, we isolated C. elegans mutants that displayed abnormal chemotactic responses to cAMP, a strong attractant for C. elegans. Based on their responses to other chemoattractants, the mutant animals could be classified into five groups: (1) animals with defective chemotaxis to cAMP only; (2) animals with defective chemotaxis to both cAMP and cGMP; (3) animals with defective chemotaxis to water-soluble attractants; (4) animals with defective chemotaxis to both water-soluble and volatile attractants; and (5) animals with enhanced chemotactic responses. We expect that analyses of these mutants will help understand the molecular mechanisms underlying chemotaxis in C. elegans.

• Animal cells and systems
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• v.16 no.2
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• pp.135-144
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• 2012

$Dendronephthya$ $castanea$ Utinomi, 1952 is a member of the family Nephtheidae, and dominates shallow waters adjacent to the southern part of Jejudo Island, Korea. This species is a gonochoric internal brooder with a sex ratio of 1:1, and releases planulae around the time of the full and new moon from July to September, when the seawater temperature peaks. The gametogenic cycle is annual, and oogenesis (12 months) is longer than spermatogenesis (4-5 months). No difference in reproductive features including sexuality, sex ratio, gametogenesis and gametogenic cycles was found between the sympatric species $D.$ $castanea$ and $D.$ $gigantea$, and there was no temporal reproductive isolation. Investigation of the morphological taxonomy and molecular biology of these species indicates that they have very similar or identical traits, suggesting an absence of speciation and a need for taxonomic reclassification.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.6
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• pp.583-590
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• 1990

Free and esterified forms of provitamin D in 30-day-old mele rat skin were isolated and quantitated using silicic acid column chromatography and high-performance liquid chromatography(HPLC) systems. Two forms of free provitamin D(cholesta-5, 7-dien-$3{\beta}$-ol and cholesta-5, 7, 24-trien-$3{\beta}$-ol) and at least thirteen esterified forms of provitamin D were isolated. The average total concentration of provitamin D in the whole skin was $6,056ng/cm^2$. The skin contained $846ng/cm^2$ of free provitamin D and $5,209ng/cm^2$ of esterified provitamin D. The proportion of esterified provitamin D in the skin was 86%.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.6
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• pp.26-33
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• 1994

Much time and labor has been conventionally paid for fine adjustment of circuit elements by experience to improve the characteristics of Tap-off for CATV systems. To solve the problem, in this paper, the relations between the even- and odd-mode impedance. Z$_{oe}$ and Z$_{oo}$ of symmetrical 4-port coupled-line directional coupler and power dividing characteristics of Tap-off for CATV system have been derived. After the coupling, the reflectivity and the isolation are represented by Z$_{oe}$ and Z$_{oo}$ only, the fine adjustment of all S-parameters can be performed by controling the elements of Z$_{oe}$ and Z$_{oo}$ only. Furthermore, the validity of the new fine adjustment method proposed here has been confirmed by experiments.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1050-1052
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• 2000

An investigation into power conditioners that interface with photovoltaic array and utilities has been completed. The rating for this investigation is residential system (3-5kW) that interface with a 220V single phase utility connection. As the result of this investigation. a 3kW high frequency PWM IGBT inverter feeding a high frequency isolation transformer with a sinusoidal current wave was selected. The output of the transformer rectified with a diode bridge rectifier four IGBT, used as 60Hz switched, reverse the polarity of the rectified current on every other half cycle of the utility voltage. Even though the high frequency link system used more power semiconductors, a net size, weight, and parts cost saving result compared to the other systems due to elimination of 60Hz transformer.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.04a
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• pp.47-52
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• 1999

In this paper we propose new approximate method for the performance analysis of closed-loop production system with unreliable machines and random processing times. The approximate method decomposes the production system consisting of K machines into a set of K subsystems, each subsystem consisting of two machines separated by a finite buffer. Then, each subsystem is analyzed by analyzing method n isolation. The population constraint of the closed-loop production system is taken into account by prescribing that the sum of average buffer level in the subsystems is equal to the number of customers in the closed-loop production system,. We establish a set of equations that characterizes unknown parameters of the servers in the subsystems. An iterative procedure is then used to determine the unknown parameters. Experimental results show that these methods provide a good estimation of the throughput.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1468-1476
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• 2006

The goal of this thesis is to support safety and reliability characteristics of software intensive critical systems. The verification method developed is innovative from current state of the art in what concerns the verification viewpoint adopted: focusing on software faults, and not, like many other approaches purely on fulfilling functional requirements. As a first step and based on a number of well defined criteria a comparison was made of available literature in the area of static non formal non probabilistic software fault removal techniques. But, None of the techniques evaluated fulfilled all criteria set in isolation. Therefore a new technique was developed based on a combination of two existing techniques: the FMEA and FTA. These two techniques complement each other very well. It is possible to integrate both techniques with commonly used techniques at system level. The resulting new technique can be shown to combine nearly all aspects of existing fault removal techniques.

• Membrane Journal
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• v.2 no.2
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• pp.91-103
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• 1992

Synthetic membrane processes are being increasingly integrated into existing reaction, isolation, and recovery schemes for the production of valuable biological molecules. In many cases they are replacing traditional unit processes. The properties of membrane systems which are most often exploited for both upstream and downstream processing and their permselectivity, high surface area per unit volume, are their potential for controlling the level of contact and/or mixing between two separate phases. Advances in both membrane materials and module design and operation have led to better control of concentration polarization and membrane fouling. After presenting some recent advances in membrane materials and fluid mechanics, we demonstrate how membranes have been integrated into cellular and enzymatic reaction schemes. This is followed by a review of established and emerging synergism between biological processes and synthetic membranes.

• Proceedings of the Membrane Society of Korea Conference
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• 1992.10a
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• pp.15-33
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• 1992

Synthetic membrane processes are being increasingly integrated into existing reaction, isolation, and recovery schemes for the production of valuable biological molecules. In many cases they are replacing traditional unit processes. The properties of membrane systems which are most often exploited for both upstream and downstream processing are their permselectivity, high surface area per unit volume, and their potential for controlling the level of contact and/or mixing between two separate phases. Advances in both membrane materials and module design and operation have led to better control of concentration polarization and membrane fouling. After presenting some recent advances in membrane materials and fluid mechanics, we demonstrate how membranes have been integrated into cellular and enzymatic reaction schemes. This is followed by a review of established and emerging membrane separation processes. Several examples are used to emphasize the synergism between biological processes and synthetic membranes.