• Korean Journal of Agricultural Science
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• v.33 no.2
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• pp.149-157
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• 2006

The objective of this research was to know useful genetic characteristics for breeding program of corn. These materials were inbreds after selfing of six or eight generations and had useful genetic informations. The emergence of Danyang Waxy Corn was faster than those of other inbred lines at 2~3 days in field conditions. The plant height of Dangyang Waxy Corn was the highest at 8 days after emergence. However the plant height of New Dangjin was the shortest with 6.25cm at 8 days after emergence, the fresh weight of New Dangjin was 0.046g at 2 days after emergence but that of Dangyang was the heaviest with 0.180g. The fresh weight of 9 inbred lines had more increments in 2 days after emergence. The mean values of dry weight also showed similar trends in 9 inbred lines. The shoot dry weight of inbred lines, Dangyang and New Dangjin was 0.045g and 0.018g at 8 days after emergence, respectively. The root length of inbred line, Dangyang, was the longest with 64.4cm at 8 days after emergence. But the root length of New Dangjin was the shortest with 20.4cm at 8 days after emergence. The fresh weight of endosperm was 0.35g at 2 days after emergence and 0.26g at 8 days after emergence in Dangyang Waxy Corn, because of reduced nutrition of endosperm.

• Journal of Environmental Impact Assessment
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• v.24 no.6
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• pp.607-618
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• 2015

Five years have passed since the first set of environmental samples was taken in 2011 to represent various ecosystems which would help future generations lead back to the past environment. Those samples have been preserved cryogenically in the National Environmental Specimen Bank(NESB) at the National Institute of Environmental Research. Even though there is a strict regulation (SOP, standard operating procedure) that rules over the whole sampling procedure to ensure each sample to represent the sampling area, it has not been put to the test for the validation. The question needs to be answered to clear any doubts on the representativeness and the quality of the samples. In order to address the question and ensure the sampling practice set in the SOP, many steps to the measurement of the sample, that is, from sampling in the field and the chemical analysis in the lab are broken down to evaluate the uncertainty at each level. Of the 8 species currently taken for the cryogenic preservation in the NESB, pine tree samples from two different sites were selected for this study. Duplicate samples were taken from each site according to the sampling protocol followed by the duplicate analyses which were carried out for each discrete sample. The uncertainties were evaluated by Robust ANOVA; two levels of uncertainty, one is the uncertainty from the sampling practice, and the other from the analytical process, were then compiled to give the measurement uncertainty on a measured concentration of the measurand. As a result, it was confirmed that it is the sampling practice not the analytical process that accounts for the most of the measurement uncertainty. Based on the top-down approach for the measurement uncertainty, the efficient way to ensure the representativeness of the sample was to increase the quantity of each discrete sample for the making of a composite sample, than to increase the number of the discrete samples across the site. Furthermore, the cost-effective approach to enhance the confidence level on the measurement can be expected from the efforts to lower the sampling uncertainty, not the analytical uncertainty. To test the representativeness of a composite sample of a sampling area, the variance within the site should be less than the difference from duplicate sampling. For that, a criterion, ${i.e.s^2}_{geochem}$(across the site variance) <${s^2}_{samp}$(variance at the sampling location) was proposed. In light of the criterion, the two representative samples for the two study areas passed the requirement. In contrast, whenever the variance of among the sampling locations (i.e. across the site) is larger than the sampling variance, more sampling increments need to be added within the sampling area until the requirement for the representativeness is achieved.

• Journal of Veterinary Clinics
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• v.22 no.4
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• pp.336-341
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• 2005

Anabolic steroid compounds are widely used for the increase of muscle mass, density of bone and athletic ability. The present study conducted to evaluate the effects of nandrolone decanoate (ND), one of the anabolic steroid compounds, on disuse muscle atrophy and healing process of bone in dogs. Twenty physically healthy dogs of both sexes were used in this experiment and divided into three groups: group A (control), group B (low dose M-1.5 mg/kg) and group C (high dose ND-7.5 mg/kg). One-mm strip of full thickness bone was excised from the radius below the pronator teres muscle for the artificial fracture and then the fractured ends were fixed in apposition with bone plate leaving 1mm gap, and finally immobilized externally by Robert John's bandage for 4 weeks. ND was administered intramuscularly once a week far 8 weeks. Body weight, muscle mass change and fracture gap of the bone were evaluated immediately after surgery, and 2, 4, and 8 weeks after surgery. The rates of muscle mass change 8 weeks after surgery were $-2.75\pm0.16\%,\;1.68\pm0.11\%\;and\;1.74\pm0.48\%$ in groups A, B and C, respectively. The significant increase (p<0.05) of muscle mass increments were found in the treated groups. The fibrous connective tissue layer in the fracture gaps of the treated groups increased more than the control, especially in the group C at 4th week. More dense fibrous connective tissue were found in the treated groups at 8th week. Collectively, our results suggested that ND was an effective anabolic agent for the immobilized disuse muscle and bone healing.

• Journal of the Economic Geographical Society of Korea
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• v.21 no.1
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• pp.20-33
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• 2018

Population distribution in urban space varies with transportation flow changing along time of day. Transportation flow is directly affected by the activities of urbanites and the distribution of related facilities, since the flow is the result of moving to the point where the facilities associated with their activities are located. It is thus necessary to analyze the spatio-temporal characteristics of the urban population distribution by integrating the distribution of activity spaces related to the daily life of urbanites and the flow of transportation. The purpose of this study is to analyze the population distribution in urban space with daily and weekly time bases using the building database and T-card database in the city of Seoul, which is rich in information on land use and transportation flow. For a time-based analysis that is difficult to grasp by general statistical techniques, a four-dimensional visualization method combining time and space using a Java program is devised. Dynamic visualization in the four-dimensional space and time allows intuitive analysis and makes it possible to understand more effectively the spatio-temporal characteristics of population distribution. For this purpose, buildings are classified into three activity groups: residential, working, and commercial according to their purpose, and the number of passengers traveling to and from each stop site of bus and subway networks in the T-card database for one week is calculated in one-minute increments, Visualizing these and integrating transportation and land use, we analyze spatio-temporal characteristics of the population distribution in Seoul. As a result, it is found that the population distribution of Seoul displays distinct spatio-temporal characteristics according to land use. In particular, there is a clear difference in the population distribution pattern along the time axis according to the mixed aspects of working, commercial, and residential activities. The results of this study can be very useful for transportation and location planning of city facilities.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.632-640
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• 2002

The objective of the study was to apply the vibration technique to reduce the viscosity of bonding adhesives and thereby compare the bond strength and resin penetration into dentinal tubules achieved with those gained using the conventional technique. Eighty-eight noncarious extracted human permanent molar teeth were sectioned to remove the coronal enamel and were embedded in 1-inch PVC pipe with acrylic resin. The occlusal surfaces were placed so that the tooth and the embedding medium were at the same level to form one flat surface, and the samples were subsequently polished with silicon carbide abrasive papers. The samples were randomly assigned to 4 groups(n=22). On Group 1 and 2, Single Bond(3M-ESPE, St. Paul, USA) was used, and on Group 3 and 4, One-Step(Bisco Inc., Schaumburg, USA) was used, and each was applied according to its manufacturer's instructions. For Group 2 and Group 4, vibration was applied with ultrasonic scaler for 10 seconds, and the adhesive was light-cured for 10 seconds. Resin composite was condensed on to the prepared surface in two increments using a mold kit(Ultradent Products Inc., USA) and each was light-cured for 40 seconds. After 24 hours in tap water at room temperature the specimens were thermocycled, and shear bond strengths were measured with a universal testing machine(Instron 4465, Canton, USA). To investigate infiltration patterns of the adhesive materials, the surface of specimen was examined with scanning electron microscope. The results were as follows. 1. The shear bond strengths of vibration groups(Group 2, Group 4) were significantly greater than those of the non-vibration groups(Group 1, Group 3)(p<0.05). 2. The shear bond strengths of Single Bond and One-Step were not significantly different (p>0.05). 3. The vibration groups showed greater number of resin tags in tubules and lateral branches under SEM.

• Journal of the Korean Chemical Society
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• v.45 no.5
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• pp.461-469
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• 2001

The combinatorial approach has been applied to discover and optimize the composition of the novel or enhanced materials. In this study, we screened the optimum composition of the system SrO-Gd$_2$O$_3$-Al$_2$O$_3$ doped with $Tb^{3+}$ by a polymerized-complex combinatorial chemistry method. Mixtures with compositions of Sr, Gd and Al component that is in the range from 0 to 1 in about 0.05 increments could be tested. The sample powders were synthesized by a polymerized complex method. To prepare appropriately polymeric precursors, we used the metallic nitrates, citric acid and ethylene glycol. The luminescence properties of the synthesized powders are investigated using the UV and VUV (Vacuum-UV: 147 nm) photoluminescence spectrometer. In addition, the crystallinity and morphology of powder were monitored by X-ray diffraction spectrometer and scanning electron microscopy. In result of VUV PL works, there are good luminescent samples with the composition of 0.595 < x < 0.733 and 0.016 < y < 0.017 in Gd1-x-yAlxTbyO$\delta$ and 0.049 < x < 0.064 and 0.02 < y < 0.039 in $Sr_xAl_{1-x-y}Tb_yO_$\delta$$, their materials can be applicable to plasma display panels as the green phosphor.

• The Korean Journal of Pharmacology
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• v.32 no.1
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• pp.1-11
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• 1996

Since it has been reported that the depolarization-induced norepinephrine (NE) release is inhibited by activation of presynaptic $A_1-adenosine$ heteroreceptor in hippocampus, a large body of experimental data on the post-receptor mechanism of this process has been accumulated. But, the post-receptor mechanism of presynaptic $A_1-adenosine$ receptor on the NE release has not been clearly elucidated yet. Therefore, it was attempted to clarify the post-receptor mechanisms of the $A_1-adenosine$ receptor-mediated control of NE release in this study. Slices from rat hippocampus were equilibrated with $^3H-norepinephrine$ and the release of the labelled products was evoked by electrical stimulation (3 Hz, 5 $Vcm^{-1}$, 2 ms, rectangular pulses), and the influence of various agents on the evoked tritium-outflow was investigated. Adenosine, in concentrations ranging from $1{\sim}30{\mu}M$, decreased the NE release in a dose-dependent manner, without affecting the basal rate of release. The adenosine effects were significantly inhibited by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, $2{\mu}M$), a selective $A_1-receptor$ antagonist. The responses to N-ethylmaleimide (NEM, 10 & $30{\mu}M$), a SH-alkylating agent of G-protein, were characterized by increments of the evoked NE-release and the basal release, and the adenosine effects were completely abolished by NEM pretreatment. $4{\beta}-Phorbol$ 12,13-dibutyrate (PDB, $1{\mu}M$), a specific protein kinase C (PKC) activator, increased the evoked NE release, whereas polymyxin B sulfate (PMB,0.1 mg), a PKC inhibitor, decreased the release, and the adenosine effects were inhibited by these agents. Nifedipine $(1{\mu}M)$, a $Ca^{2+}-channel$ blocker of dihydropyridine analogue, did not affect the adenosine effect. Tetraethylammonium (TEA, 3 mM) increased the evoked NE release, and inhibited the adenosine effects, but glibenclamide, a ATP dependent $K^+-channel$ blocker, did not. Finally, 8-bromo cyclic AMP (100 & $300{\mu}M$), a membrane-permeable analogue of cAMP, did not alter the NE release, but adenosine effects were inhibited by pretreatment with 8br-cAMP. These results suggest that the decrement of the evoked NE-release by $A_1-adenosine$ receptor is mediated by the C-protein, which is coupled to protein kinase C, adenylate cyclase system and TEA sensitive $K^+-channel$, and that nifedipine-sensitive $Ca^{2+}-channel$ and glibenclamide-sensitive $K^+-channel$ are not involved in this process.

• Journal of Preventive Medicine and Public Health
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• v.17 no.1
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• pp.25-29
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• 1984

To assess the effect of noise on the blood pressure of workers, 70 weaving and 70 refining female workers in 15 to 24 years of ages were tested for the changes of blood pressure before and after exposure to the noise. The noise levels at work place were 99 dB (A) for weavers and 80 dB(A) for refiners. The mean age of refiners was 17,7 years and that of weavers was 18.6 years, and the difference in mean ages was statistically significant (p<0.05). The means of heights, weights and working durations were not significantly different between two groups. The mean systolic blood pressure of the weavers was 112.5mmHg before exposure to the noise and it was increased to 115.7mmHg after exposure to 99 dB(A) of noise for 30 minutes, and the mean diastolic blood pressure from 71.6mmHg to 74.1mmHg. These increments of blood pressure were statististically significant (p<0.05). The mean systolic blood pressure of the refiners was decreased from 108.9mmHg to 106.7mmHg after exposure to 80 dB(A) of noise for 30 minutes, and the mean diastolic blood pressure from 67.3mmHg to 67.1mmHg. These changes of blood pressure were not statistically significant. The mean systolic and diastolic blood pressure of the weavers before exposure to the noise were significantly higher than that of refiners (p<0.05). The difference of blood pressure between refiners and weavers was significantly associated with noises (p<0.05), and not ages and their interactions. The study results support the hypothesis that exposure to excessive noise increases the blood pressure of workers.

• Korean Journal of Weed Science
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• v.9 no.2
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• pp.168-173
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• 1989

In the characteristics of intra-specific competition according to bulrush density, the intra-specific competition in plant height began at 5 and 15% per pot in mixed culture and bulrush monoculture, respectively. The intra-specific competition in the shoot began at 5 plants per pot in both mixed culture and bulrush monoculture. The competition in dry matter weight began at 15 plants per pot in monoculture, and at 10 plants in mixed culture. On the rice density, the plant height, and numbers of shoot and dry matter weight in rice were rapidly increased up to 2.6, and 2.5 plants per pot, respectively, And then the increments were slow, The critical intra-specific competition of bulrush with rice was 2.5 to 3 plants per pot in their traits of rice, and especially the number of shoots and dry matter weights per pot showed significant decrements. In the different transplanting time in rice, the plant heights in both rice and bulrush elongated longer in mixed culture than in monoculture. The plant height of bulrush became shorter but the height of rice longer with late transplanting. The ratio of shoot number in rice to the number in bulrush was about 1 : 3 in all plots, and shoot numbers became less by late transplanting. The dry matter weight in both species were decreased by late transplanting, and the decrements were more prominent in bulrush than in rice.

• Proceedings of the KACD Conference
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• 2008.05a
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• pp.246-257
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• 2008

The purpose of this study was to investigate the influence of various occlusal loading sites and directions on the stress distribution of the cervical composite resin restorations of maxillary second premolar, using 3 dimensional (3D) finite element (FE) analysis. Extracted maxillary second premolar was scanned serially with Micro-CT (SkyScan1072; SkyScan, Aartselaar, Belgium). The 3D images were processed by 3D-DOCTOR (Able Software Co., Lexington, MA, USA). HyperMesh (Altair Engineering. Inc., Troy, USA) and ANSYS (Swanson Analysis Systems. Inc., Houston, USA) was used to mesh and analyze 3D FE model. Notch shaped cavity was filled with hybrid (Z100, 3M Dental Products, St. Paul, MN, USA) or flowable resin (Tetric Flow, Viva dent Ets., FL-9494-Schaan, Liechtenstein) and each restoration was simulated with adhesive layer thickness ($40{\mu}m$). A static load of 200 N was applied on the three points of the buccal incline of the palatal cusp and oriented in $20^{\circ}$ increments, from vertical (long axis of the tooth) to oblique $40^{\circ}$ direction towards the buccal. The maximum principal stresses in the occlusal and cervical cavosurface margin and vertical section of buccal surfaces of notch-shaped class V cavity were analyzed using ANSYS. As the angle of loading direction increased, tensile stress increased. Loading site had little effect on it. Under same loading condition. Tetric Flow showed relatively lower stress than Z100 overall, except both point angles. Loading direction and the elastic modulus of restorative material seem to be important factor on the cervical restoration.