• The Korean Journal of Ecology
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• v.19 no.2
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• pp.151-163
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• 1996

To investigate the early symptoms of light-chilling, alterations of chlorophyll fluorescence transients were monitored in cucumber (Cucumis sativus L. cv. Ilmichungjang) leaves. During 24 h chilling, decreases in (Fv)m/Fm, qE and qQ, and an increase in Fo were observed. The chilling effects were not recovered at room temperature, and a significant increase in Fo was observed during the recovery period. After 6 h chilling, ‘dip’(D) level of the transients became obscure, and the negative slope after ‘peak’(P) disappeared. The first derivative (dFv/dt) of the fast fluorescence rise curve was used to obtain more accurate information about the changes in the transients. The maximal rate of the fluorescence increase in the D-p rise curve (Fr) has been the most frequently used chilling stress indicator. However, a correct value of Fr could not be measured when the D level became obscure. This problem was overcome by introducing a new indicator, HFr (dFv/dt at Fv = 1/2 (Fv)m), and HFr gave very similar values to Fr. To monitor the changes in curvature around D level, another new parameter, ${\Delta}S$(D-Fr), was also introduced. These three parameters decreased very sensitively during light-chilling. In addition, increases in these parameters were observed during the first 2 h chilling, but this increase in Fr was also observed in pea leaf discs dark-chilled for 15 min, suggesting that this very early change is a common response to chilling in both pea and cucumber leaves. Quenching coefficients were also very sensitive to chilling, especially qE. Discussion on the usage of these parameters as chilling stress indicators is given in the text.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.9
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• pp.1320-1325
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• 2003

The purpose of present study was to assess the effect of polyunsaturated fatty acids (PUFA) on the immune responses of laying hens. Three hundred and sixty hens at the age of 60 weeks were randomly assigned to ten diets, which contained no oil (CK), 1%, 3%, 5% fish oil (FO); 2%, 4%, 6% linseed oil (LO) and 2%, 4%, 6% corn oil (CO). After 5 weeks of feeding experimental diets, humoral and cellular immune responses were assayed. Laying hens were injected with Sheep Red Blood Cell (SRBC) and Bovine Serum Albumin (BSA) and antibody titers, which were measured on d6, d10, d14 after primary challenge and on d5, d9, d13 after secondary challenge. Concanavalin (ConA) and lipopolysaccharide (LPS) -stimulated proliferation of peripheral blood and spleen lymphocytes were assessed by [$^3$H] thymidine incorporation at the week age of 5 and 10, respectively. The results showed that antibody titers in FO-fed and LO-fed laying hens were higher than that in laying hens fed CO. The proliferation response to ConA was lower in laying hens that fed oils rich in n-3 fatty acids than that in laying hens fed CO. Higher level n-3 fatty acids can improve immune functions of laying hens. In conclusion, dietary fat source and level had a significant impact on immune responses of laying hens.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.6
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• pp.48-51
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• 2009

One-stage low noise amplifier (LNA) using 65 nm RF CMOS technology below 20 GHz is designed to find the optimal bias voltage and optimal width of input transistor so that the maximum figure of merit (FoM) has been achieved. If the frequency is higher than 13 GHz, the amplifier needs two-stage to achieve the higher gain. If the frequency is lower than 5 GHz, one additional capacitor between gate and source should be added to control the power under the limitation. This paper summarizes one-stage LNA overall performances below 20 GHz and this approach can also be applied to other CMOS technology of LNA designs.

• Journal of IKEEE
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• v.24 no.4
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• pp.1058-1063
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• 2020

This paper proposes a 12-bit SAR A/D(Successive Approximation Register Analog-to-Digital) converter that operates at low power for bio-signal and sensor signal processing. The conventional SAR A/D converter utilized the reduction of the dynamic current, which resulted in reducing total power consumption. In order to solve the limitation of the sampling time due to charging/discharging of the capacitor for reducing dynamic current, the different sampling time on the C-DAC bit switch operation was applied to reduce the dynamic current. In addition, lowering the supply voltage of the digital block to 0.6V led to 70% reduction of the total power consumption of the proposed ADC. The proposed SAR A/D was implemented with CMOS 65nm process 1-poly 6-metal, operates with a supply voltage of 1.2V. The simulation results demonstrate that ENOB, DNL/INL, power consumption and FoM are 10.4 bits, ±0.5LSB./±1.2LSB, 31.2uW and 2.8fJ/step, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.532-539
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• 2015

Inhibition of osteoclast differentiation is the most important target for prevention of inflammatory bone resorption and bone diseases. Here, we investigated the effect of spinach ethanol extract on osteoclast differentiation in RAW264.7 cells. Spinach was extracted with ethanol at a concentration ranging from 0 to 100% (0, 25, 50, 75, and 100% ethanol). Inhibitory effects of receptor activator of NF-${\kappa}B$ ligan (RANKL)-induced osteoclast differentiation were evaluated using tartrate-resistant acid phosphatase (TRAP) stain assay. The most effective eanol concentration for osteoclast differentiation was 100%. Spinach extract (100% ethanol) suppressed RANKL-induced osteoclast differentiation and TRAP activity. Spinach extract (100% ethanol) also suppressed expression of osteoclast differentiation-related marker genes (NFATc1, c-FOS, cathepsin K, and TRAP) and down-regulated RANKL-induced NF-${\kappa}B$ and ERK phosphorylation during osteoclast differentiation. Taken together, our results suggest that spinach extract is effective against reducing osteoclast differentiation through the NF-${\kappa}B$-mediated pathway.

• Journal of The Korean Astronomical Society
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• v.49 no.6
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• pp.295-306
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• 2016

We present the results of BV time-series photometry of the globular cluster NGC 288. Observations were carried out to search for variable stars using the Korea Microlensing Telescope Network (KMTNet) 1.6-m telescopes and a 4k pre-science CCD camera during a test observation from August to December, 2014. We found a new SX Phe star and confirmed twelve previously known variable stars in NGC 288. For the semi-regular variable star V1, we newly determined a period of 37.3 days from light curves spanning 137 days. The light-curve solution of the eclipsing binary V10 indicates that the system is probably a detached system. The pulsation properties of nine SX Phe stars were examined by applying multiple frequency analysis to their light curves. We derived a new Period-Luminosity (P-L) relation, ${\langle}M_V{\rangle}=-2.476({\pm}0.300){\log}P-0.354({\pm}0.385)$, from six SX Phe stars showing the fundamental mode. Additionally, the period ratios of three SX Phe stars that probably have a double-radial mode were investigated; $P_{FO}/P_F=0.779$ for V5, $P_{TO}/P_{FO}=0.685$ for V9, $P_{SO}/P_{FO}=0.811$ for V11. This paper is the first contribution in a series assessing the detections and properties of variable stars in six southern globular clusters with the KMTNet system.

• Nutritional Sciences
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• v.4 no.1
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• pp.3-12
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• 2001

Long chain polyunsaturated fatty acids (LCPUFA) are important components of brain phospholipds and play important role (s) in brain function. In rats, the maximum brain growth occurs during the period of lactation even though it happens during the third trimester of gestation in human. Since milk contained docosahexaenoic acid (DHA) even through the maternal diet had no DHA and/or a very small amount of its precursor, $\alpha$-linolenic acid ($\alpha$-LnA), an emphasis was given to maternal adipose tissue as a reservoir of this fatty acid. We, therefore, investigated the mesenteric and subcutaneous adipose tissues for their fatty acid composition in dams reared with different fat diets. Diets containing various amounts of $\omega$6 and $\omega$3 fatty acids were given to adult female rats (200-250g) throughout the pregnancy and lactation periods. Diets were composed of 10% (wt/wt) corn oil (CO), soybean oil (SO), perilla seed oil (PO) containing about 60% $\alpha$-LnA, or fish oil (FO) rich in eicosapentaenoic acid (EPA) and DHA. The fatty acid ompositions of mesenteric and subcutaneous fat were measured and evaluated at Day-2 and Day-15 after parturition. In general, major characteristics of dietary fatty acid composition was reflected on the fatty acid composition of adipose tissues. Dietary fatty acid composition was reflected more on mesenteric fat as compared to subcutaneous fat. Mesenteric fat was found to contain less arachidonic acid (AA) and mesenteric fats of CO, SO and PO groups contained less DHA than did the subcutaneous fat. The P/M/S ratios of adipose tissues were similar between experimental groups while dietary P/M/S ratios differed significantly. It was noticeable that a small proportion of DHA was found in the adipose tissues of animals of CO, SO and PO groups (Day-2) and in SO and PO groups (Day-15), the groups which do not contain DHA in their diets. The percentage of DHA in mesenteric fat o CO, SO and PO groups decreased as lactation continues, while the proportion of DHA in FO group increased. Adipose tissues of FO group had higher DHA/EPA ratio as compared to the diet. Considering the fact that the body contains a large amount of adipose tissues, our present finding suggests that the adipose tissue can serve as a reservoir of DHA for pregnant and lactating rats.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2249-2254
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• 1994

An observation which is useful for hardware implementation of programmable FIR filters with powers-of two coefficients (2PFIR filters) is made. Specifically, it is shown that the exponents of filter coefficients representable by the canonical signed digit(CSD) code with M ternary digits can be chosen from some subsets of {0, 1, $\cdots$, M-1}. This observation naturally leads to 2PFIR filters with shorter shifters whose length is strictly less than M and, as a consequence, leads to an efficient hardware structure fo programmable 2PFIR filtering. In addition, we present some experimental results indicating that the shifters of 2PFIR filters can be shortened further in some cases.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.8
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• pp.423-431
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• 2000

This paper presents a systematic approach to the input-output data-based fuzzy modeling for the complex and uncertain nonlinear systems, in which the conventional mathematical models may fail to give the satisfying results. To do this, we propose a new method that can yield a successful fuzzy model using a mGA hybrid schemes with a fine-tuning method. We also propose a new coding method fo chromosome for applying the mGA to the structure and parameter identifications of fuzzy model simultaneously. During mGA search, multi-purpose fitness function with a penalty process is proposed and adapted to guarantee the accurate and valid fuzzy modes. This coding scheme can effectively represent the zero-order Takagi-Sugeno fuzzy model. The proposed mGA hybrid schemes can coarsely optimize the structure and the parameters of the fuzzy inference system, and then fine tune the identified fuzzy model by using the gradient descent method. In order to demonstrate the superiority and efficiency of the proposed scheme, we finally show its applications to two nonlinear systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.7
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• pp.1244-1255
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• 1994

The wireless-LAN(Local Area Network), which is emerged as a solution to cable problem and increasing requirement for communication network, has a several problem when it transmit information MAN protocol by used wired-LAN`s MAC protocol. Media Access protocol in Wireless-LAN has great effect on system performance and much studies are processing now. The PRMA(Packet Reservation Multiple Aeecss) of reservation method has a disadvantage that the system performance was degraded become of delay time in the reservation step as a resulting of collision. In this paper, using the TDD(Time Division Duplex) method amd modified PRMA method wireless-LAN modelled to overcome disadvantage, that id delay time due to collision in reservation step. The performance evaluation fo the model was done using M/M/1//M process model and this was simulation using SLAM.