• Proceedings of the KACD Conference
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• 2001.05a
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• pp.241-242
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• 2001

Tooth resorption os perplexing problem for all dental practitioners. The etiology factors and diagnosis are vague, chosen treatment dose not prevent the rapid disappearance of the calcified dental tissues. Since the etiologic factors, diagnosis, treatment and prognosis differ for these various types of resorptive defects, it is important to diagnose resorption radiographically or clinicall and distinguish internal from external resorption. Following these cases are internal root resorption, external root resorption of serious complication subsequent to avulsion and traumatic injury.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.4
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• pp.471-478
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• 2011

The objectives were to compare the ability of various rumen microbial fractions to reduce nitrate and to assess the effect of nitrate on in vitro fermentation characteristics. Physical and chemical methods were used to differentiate the rumen microbial population into the following fractions: whole rumen fluid (WRF), protozoa (Pr), bacteria (Ba), and fungi (Fu). The three nitrogen substrate treatments were as follows: no supplemental nitrogen source, nitrate or urea, with the latter two being isonitrogenous additions. The results showed that during 24 h incubation, WRF, Pr and Ba fractions had an ability to reduce nitrate, and the rate of nitrate disappearance for the Pr fraction was similar to the WRF fraction, while the Ba fraction needed an adaptation period of 12 h before rapid nitrate disappearance. The WRF fraction had the greatest methane ($CH_4$) production and the Pr fraction had the greatest prevailing $H_2$ concentration (p<0.05). Compared to the urea treatment, nitrate diminished net gas and $CH_4$ production during incubation (p<0.05), and ammonia-N ($NH_3$-N) concentration (p<0.01). Nitrate also increased acetate, decreased propionate and decreased butyrate molar proportions (p<0.05). The Pr fraction had the highest acetate to propionate ratio (p<0.05). The Pr fraction as well as the Ba fraction appears to have an important role in nitrate reduction. Nitrate did not consistently alter total VFA concentration, but it did shift the VFA profile to higher acetate, lower propionate and lower butyrate molar proportions, consistent with less $CH_4$ production by all microbial fractions.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.329-332
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• 2001

It has been known that, in enzymatic synthesis of cephalexin, the conversion yield was reduced by high loading of ampicillin acylase. In order to elucidate this phenomena, pH-controlled synthesis of cephalexin was examined using a purified Acetobacter turbidans acylase. When the pH of the reaction mixture was maintained at $6.20{\pm}0.04$, the reduction of the maximal conversion rate was not observed even with high enzyme loading. The kinetic parameters also suggest that pH drop during the enzymatic synthesis of cephalexin was mainly attributed to the rapid hydrolysis of D-${\alpha}$-phenylglycine methyl ester to D-${\alpha}$-phenylglycine, rather than the disappearance of 7-amino-3-deacetoxycephalosporanic acid for cephalexin synthesis. At higher molar ratio of two substrates, [D-${\alpha}$-phenylglycine methyl ester]/[7-amino-3-deacetoxycephalosporanic acid], the conversion rate was also elevated under pH-controlled enzymatic synthesis, which implies that the main reason for the pH drop is due to the production of D-${\alpha}$-phenylglycine methyl easter, the effect of a water-methanol cosolvent system on the ester, the effect of a water-methanol cosolvent system on the conversion profile was also examined. Even the though the conversion rate was increased in 10% methanol solution, a higher than 16% methanol in the reaction mixture caused an inactivation of enzyme.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.1
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• pp.59-65
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• 2014

To obtain an elliptical trajectory at the cutting edge during elliptical vibration cutting, sinusoidal voltage excitations of two piezoelectric actuators have commonly been used. In this study, PWM excitation, which is relatively simple to generate, was employed and its characteristics were investigated. In experimental and analytical analyses, we found that for PWM excitation, the integer-multiple frequencies of the excitation voltage distorted the shape of the elliptical trajectory, whereas at a duty ratio(DR) of 50%, the distortion of the elliptical trajectory was minimized due to disappearance of the first overtone. When the magnitude of the maximum excitation voltage was maintained at the same level for both PWM and sinusoidal excitation, PWM (DR=50%) excitation produced a greater vibration amplitude than sinusoidal excitation but resulted in more rapid saturation of a high-frequency power amplifier.

• Nuclear Engineering and Technology
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• v.31 no.4
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• pp.385-390
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• 1999

Ovarian follicles are faced with one of two fates, atresia or development. Up to 99% of follicles become degenerated rather than ovulated in female life span. Thus, atresia occurs at all stages of follicle development in mammalian ovaries. In the present experiment, the effect of ${\gamma}$-radiation on primordial follicles was morphologically analyzed in a mouse ovary. Thirty-seven percent of the primordial follicles in the non-irradiated control mice ovaries were abnormal. At day 8 post irradiation, most of primordial follicles became atretic. They lost their integrity of architecture in the follicular shape. Then, all the oocytes disappeared from the follicles. And only 3 to 4 granulosa cells lay down onto the basement membrane. Disappearance of granulosa cells or oocytes resulted from the radiation-induced apoptotic process. It is definitely clear that ${\gamma}$-radiation induces rapid apoptotic degeneration of the primordial follicles. The morphological degeneration induced by radiation in the primordial follicles can be used as an experimental model to draw out a deeper insight for radioprotectant researches.

• The Korean Journal of Ecology
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• v.24 no.4
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• pp.227-232
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• 2001

The biomass structure for three major components viz., the dominant grass, Chrysopogon zeylanicus Thw., the 'other grasses' and the'remaining species'and dry matter dynamics for total community were studied over a period of one year in an annual fire influenced subtropical humid grassland community in Western Ghats, India. The biomass of aboveground, belowground and litter compartments were high as in other humid grasslands and generally have positive correlation with rainfall, rainy days and relative humidity with the exception of litter parts. The above and belowground net primary productions (4,561 and 722 g/㎡, respectively) were also higher and were comparable with other humid tropical grasslands. The turnover of organic matter was rapid, Of the total input of 14.47 g/㎡ into the system, about 86.3% was allocated to above ground parts and 13.7% to below ground parts. The total disappearance was 2.56 g/㎡ and it was accounted to be 17.68% of the total output. The net surplus of dry matter (82.32%) in the post fire community indicates that the grassland was maintained in a seral stage. Hence it is suggested that prescribed burning may keep this ecosystem in a highly productive and seral stage.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.648-651
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• 2014

In this paper, we introduce the trends in age-related health care services for dementia research due to the rapid aging society. In Korea, the current increase in dementia patients and the disappearance of runaway because social welfare policy is insufficient state and requires a lot of effort in order to protect the patient's guardian. Therefore, In this paper, we propose the need for a monitoring service for dementia patients. The attachment by the wearable sensor and monitor the mobility of the patient causes the protector as possible to trace the location of the patient to monitor the safety of the patient standing with the system provides.

• Bulletin of the Korean Chemical Society
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• v.11 no.4
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• pp.281-286
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• 1990

The kinetics and mechanism of reduction of Cu(II) with an excess D-penicillamine have been examined at pH = 6.2 and 0.60M in ionic strength. The reaction at the initial stage is biphasic with a rapid complexation process to give "red" transient complex of $[Cu(II)(pen)_2]^2$- that is partially reduced to another transient "brown" intermediate. The "brown" intermediate is finally reduced to diamagnetic "yellow" complex, $[Cu(I)(Hpen)]_n$. The final reduction process is pseudo-first order in ["brown" transient] disappearance $with {\kappa} = {{\kappa}_{3a} + {\kappa}_{3b}[pen]^{2-}},$ where ${\kappa}_{3a} = (5.0{\pm}0.8){\times}10^{-3}sec^{-1}$ and ${\kappa} = (0.14{\pm}0.02) M^{-1}sec^{-1}$ at $25^{\circ}C$. The activation parameters for the $[H_2pen]$-independent and $[H_2pen]$-dependent paths are ${\Delta}H^{\neq} = (52{\pm}5)kJmol^{-1},$ and ${\Delta}S^{\neq} = ( - 27{\pm}3)JK^{-1}mo^{l-1},$ and ${\Delta}H^{\neq} = (56{\pm}2)kJmol^{-1}$ and ${\Delta} S^{\neq} = ( - 18{\pm}0.7)JK^{-1}mol^{-1}$ respectively. The nature of "brown" intermediate is not clearly identified, but this intermediate seems to be in the mixed-valence state, judging from the kinetic and spectroscopic informations.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.41.3-42
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• 2021

Conventional global magnetic field maps, such as daily updated synoptic maps, have been constructed by merging together a series of observations from the Earth's viewing direction taken over a 27-day solar rotation period to represent the full surface of the Sun. It has limitations to predict real-time farside magnetic fields, especially for rapid changes in magnetic fields by flux emergence or disappearance. Here, we construct accurate synchronic magnetic field maps using frontside and AI-generated farside data. To generate the farside data, we train and evaluate our deep learning model with frontside SDO observations. We use an improved version of Pix2PixHD with a new objective function and a new configuration of the model input data. We compute correlation coefficients between real magnetograms and AI-generated ones for test data sets. Then we demonstrate that our model better generate magnetic field distributions than before. We compare AI-generated farside data with those predicted by the magnetic flux transport model. Finally, we assimilate our AI-generated farside magnetograms into the flux transport model and show several successive global magnetic field data from our new methodology.

• Journal of Animal Science and Technology
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• v.45 no.2
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• pp.241-250
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• 2003

Accurate and rapid evaluation of the nutritional quality of Korean straws is important because of the recent increase in the use of these feedstuffs in Korean. The aim of the study was to establish with relationships between ruminal fermentation of Korean straws and in vitro gas production using a pressure transducer. The pressure transducer system includes pressure censors, AD board, LED monitor, and the computer with real-time graphics. Both gas production and DM digestibility data were fitted into the exponential equation P = a + b (1-e-$1-e^{-ct}$). The initial rate of gas production was highest for rice straw, followed by barley straw and wheat straw. The gas production rate of constant (c) in gas production for rice straw, wheat straw, and barley straw were 3.8, 2.5, and 2.5 $%h^{－1}$, respectively. Total VFA concentration (mM) produced after 72h incubation was similar among three Korean straws, even though was variable during the early (12h) fermentation. Volume of gas production was related (P> 0.05: r = 0.76 to 0.83) to DM disappearance and also strongly related (p< 0.05: r = 0.91 to 0.98) to VFA concentration at all incubation times. Linear correlation showed between gas production and DM disappearance and VFA by in vitro will be matched in in vivo digestibility.