• The Korean Journal of Ecology
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• v.20 no.1
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• pp.35-41
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• 1997

Effects of cadmium on growth and nitrogen fixation activity of Melilotus suaveolens, a biennial legume plant dominating in the area of poor soil were quantitatively analyzed during the growing period. Cadmium treatments of 10, 30 and 100 ppm resulted in 12, 22 and 35% inhibition of plant height and 14, 25 nd 26% reduction of chlorophyll contents of leaves, respectively. The plant biomass reduced 51, 70 and 89% for leaves, 33, 50 and 59% for stems, and 42, 52 and 70% for roots, respectively by 10, 30 and 100 ppm Cd treatments. Cadmium contents of roots treated with 10, 30 and 100 ppm Cd were 62, 112 and 183 folds higher than that of the control, respectively. Cadmium contents of stems were about 1/2.2 of those of roots, but leaves contained only 1/27.8 of those of roots. Cadmium treatments resulted in increase of T/R ratios and decrease of F/C ratios significantly in the later growth period. Nodule formation was reduced to 8% in 42 days by the treatment of 100 ppm Cd. Specific nitrogen fixation activity of nodules attained 61.0, 24.0, 1.6 and 0.7 mol $C_2H_4{\cdot}g$ fr wt $nodule^{-1}{\cdot}h^{-1}$ on 42nd day, respectively for 0, 10. 30 and 100 ppm of Cd treatments. Total amount of nitrogen fixation per plant reduced by 73, 98 and 99% with the treatments of 10, 30 and 100 ppm Cd.

• ETRI Journal
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• v.36 no.3
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• pp.385-395
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• 2014

In this paper, we consider a resource allocation scheme for millimeter wave-based wireless personal area networks using directional antennas. This scheme involves scheduling the reservation period of medium access control for IEEE 802.15.3c. Objective functions are considered to minimize the average delay and maximize throughput; and two scheduling algorithms-namely, MInMax concurrent transmission and MAxMin concurrent transmission-are proposed to provide a suboptimal solution to each objective function. These are based on an exclusive region and two decision rules that determine the length of reservation times and the transmission order of groups. Each group consists of flows that are concurrently transmittable via spatial reuse. The algorithms appropriately apply two decision rules according to their objectives. A real video trace is used for the numerical results, which show that the proposed algorithms satisfy their objectives. They outperform other schemes on a range of measures, showing the effect of using a directional antenna. The proposed scheme efficiently supports variable bit rate traffic during the reservation period, reducing resource waste.

• BMB Reports
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• v.49 no.11
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• pp.587-589
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• 2016

The circadian clock system enables organisms to anticipate the rhythmic environmental changes and to manifest behavior and physiology at advantageous times of the day. Transcriptional/translational feedback loop (TTFL) is the basic feature of the eukaryotic circadian clock and is based on the rhythmic association of circadian transcriptional activator and repressor. In Drosophila, repression of dCLOCK/CYCLE (dCLK/CYC) mediated transcription by PERIOD (PER) is critical for inducing circadian rhythms of gene expression. Pacemaker neurons in the brain control specific circadian behaviors upon environmental timing cues such as light and temperature cycle. We show that amino acids 657-707 of dCLK are important for the transcriptional activation and the association with PER both in vitro and in vivo. Flies expressing dCLK lacking AA657-707 in $Clk^{out}$ genetic background, homologous to the mouse Clock allele where exon 19 region is deleted, display pacemaker-neuron-dependent perturbation of the molecular clockwork. The molecular rhythms in light-cycle-sensitive pacemaker neurons such as ventral lateral neurons ($LN_vs$) were significantly disrupted, but those in temperature-cycle-sensitive pacemaker neurons such as dorsal neurons (DNs) were robust. Our results suggest that the dCLK-controlled TTFL diversify in a pacemaker-neuron-dependent manner which may contribute to specific functions such as different sensitivities to entraining cues.

• Food Science of Animal Resources
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• v.35 no.2
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• pp.216-224
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• 2015

The objective of present study was to evaluate the effects of the application of chitosan and chitosan/whey protein on the chemical, microbial and organoleptic properties of Göbek Kashar cheese during ripening time (on 3^rd, 30^th, 60^th and 90^th d). Difference in microbiological and chemical changes between samples was found to be significant (p<0.05) during ripening period. Cheese samples with edible coating had statistically lower mould counts compared to the uncoated samples. Furthermore the highest and lowest mould counts were determined in control (4.20 Log CFU/g) and other samples (<1 Log CFU/g) at 60^th and 90^th d of storage. All samples exhibited higher levels of water soluble nitrogen and ripening index at the end of storage process. At the end of 90 day storage period, no signicant dierences in salt and fat values were observed among the cheeses studied. The edible coatings had a beneficial effect on the sensory quality of cheese samples. In the result of sensory analysis, while cheese C and the chitosan coated cheese samples were more preferred by the panellists, the chitosan/whey protein film-coated cheese samples received the lowest scores. This study shows coating suggests could be used to improve the quality of cheese during ripening time.

• Journal of Microbiology
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• v.42 no.1
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• pp.1-8
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• 2004

Changes in the bacterial populations of a 5-stage biological nutrient removal (BNR) process, with a step feed system for wastewater treatment, were monitored by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA fragments. DGGE analysis indicated seasonal community changes were observed, however, community profiles of the total bacteria of each reactor showed only minor differences in the samples obtained from the same season. The number of major bands was higher in the summer samples, and decreased during the winter period, indicating that the microbial community structure became simpler at low temperatures. Since the nitrogen and phosphate removal efficiencies were highly maintained throughout the winter operation period, the bacteria which still remaining in the winter sample can be considered important, playing a key role in the present 5-stage BNR sludge. The prominent DGGE bands were excised, and sequenced to gain insight into the identities of the predominant bacterial populations present, and most were found to not be closely related to previously characterized bacteria. These data suggest the importance of culture-independent methods for the quality control of wastewater treatment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1215-1220
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• 2004

Cell adhesion to any material surface is considered to be fundamental and important phenomenon in the fields of tissue engineering. Cell adhesion molecules, mechanism, and attachment force have been studied and described a lot. However, the effects of mechanical stimuli on the adhesive forces still have been left much to be investigated. In this study, to investigate the changes in cell adhesive force due to resting time period during the intermittent hydrostatic pressurizing (IHP), cells were cultured under the IHP with various resting times. Then the cell adhesive forces were measured quantitatively utilizing a cell detachment test system and immunofluorescent staining was performed using fluorescent microscopy. In the results, immediately after mechanical stimuli (150 minutes after seeding) and one hour later (210 minutes after seeding), the average adhesive force of experimental group 5 (resting time: 15min) compared with that of control group at same culture time was increased significantly (p<0.05). The results indicated that IHP can contribute in improving cell adhesive force and some of time intervals were required for the expression of cell response.

• Nutritional Sciences
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• v.8 no.4
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• pp.231-236
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• 2005

This study investigated the changes in the neuronal nitric oxide synthase (nNOS) and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activities during food restriction in the rat brain such as cerebral cortex, cerebellum, caudate pautamen and hypothalamus. The rats were placed on a restricted feeding schedule consisting of half the ad libitum quantity for 3 days and 1, 2, 4, 6 and 9 weeks, and a free feeding schedule for 4 weeks. The loss of body weight peaked after 1 week of food restriction and persisted during the entire 9-week period of food restriction. The dramatic weight change in the first week ($12\%$) and the reduction in weight changes thereafter suggest that major adaptation changes occur early and body maintenance occurs subsequently. In the hypothalamus, the optical densities of the NADPH-d and nNOS immunoreactivities were found to be significantly higher in the 1-week and lower in the 9-week food restricted group than in the ad libitum fed control rats. In contrast, in the cerebral cortex, the optical densities of the NADPH-d- and nNOS-positive neurons were not changed significantly during the period of food restriction. This study provides the morphological evidence showing that food restriction has a significant effect on the nitric oxide synthesizing system of the hypothalamus.

• Journal of the Korean Society of Costume
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• v.52 no.8
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• pp.123-135
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• 2002

The purposes of this study were to observe the influences of Salon culture on fashion, and to understand of 17th-l8th century's costume from a different point of view. The literatures about Salons and costume in 17th-l8th century were considered for this study Salon culture had influenced on women's and men's fashion from 17th 18th century as results. The influences of salon culture on fashion were as follows; At first, it caused radical feminism for women's dress. Women for this period chose their dress to maximize their breast and tight their waist radically to express their beauty. Women were realized as sexual being for the period, then, this caused feminism. The second influence was the Andorgynous of men's dress. Men maximized beautiful decoration, body line on their dress and showed feminine dress style. which caused Andorgynous of men's dress as men and women mutually created new beauty effect. Salon had influences on the birth of new feminine culture and fashion, supplying individual self-control and freedom to women not as aesthetic objects.

• Journal of Advanced Marine Engineering and Technology
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• v.13 no.1
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• pp.57-68
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• 1989

This paper treats the analytical and experimental studies on the improvement of commutating circuit for the speed control of DC motor. A simple circuit composed of R, L and C elements is proposed here for switching off power SCR carrying the load current. The real important in this chopper circuit is to determine the reasonable values of commutating circuit constants. In this paper, the reasonable values of the commutating circuit constants are basically determined on a view point of commutating performances in the given circuit model and must satisfy the following conditions. The first, the peak commutating current should be larger than the anticipated maximum load current. The second, the circuit turn-off time (tc) must be longer than the SCR turn-off time (tq). The third, the resistor should be enough large to permit the current to be neglected in the analysis of the commutation circuit, as well as be enough small to permit to charge the capacity voltage (Ec) to the half the value of source voltage (E) before the next communication cycle is initiated. The last, the period of chopping signal must be the least possible multiple of the damping vibration period of commutating circuit. The improved chopper circuit used in the experiment under unloaded condition was composed to meet the reasonable conditions mentioned above, and a successful commuting performance was achieved without failure. Several types of microprocessor having a different value of CPU speed individually have been applied to the experiment under the loaded conditions. Also it shows that the faster the speed of CPU is, the more stable the commutation turns out.

• Toxicological Research
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• v.19 no.2
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• pp.123-131
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• 2003

This study was carried out to assess the combined repeated dose, reproduction and developmental toxicities of benzoyl peroxide for OECD SIDS (Screening Information Data Set) program. Male and female Sprague-Dawley rats were exposed to benzoyl peroxide at dose levels of 0, 250, 500 and 1,000 mg/kg/day for 29 days for males and for 41-51 days for females. No deaths were found in all animals including control group during exposure period. No hematological effects attributable to benzoyl peroxide were observed in all treated groups. Significant decrease in the weight of testes and epididymis were observed in males at 1,000 mg/kg/day. In females at 1,000 mg/kg/day, slight histopathological effects in uterus such as epithelial vacuolation or hyperplasia were observed. No treatment-related changes in precoital time and rate of copulation, fertility and gestation period were noted in all treated groups. There was no evidence of teratogenic effect of benzoyl peroxide, but body weight of pups at 1,000 mg/kg/day was significantly decreased. NOAEL for combined repeated dose and reproduction/developmental toxicity was 500 mg/kg/day.