• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.1
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• pp.26-30
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• 2009

Background and Objectives: To determine the anatomic position of the inferior alveolar nerve (IAN) canal in patients with mandibular prognathism using the cone-beam CT (CBCT). Materials and Methods: Fifty rami from 25 patients were evaluated. The images were taken by i-CAT and reconstructed 3-dimensionally using the Simplant 11 program. The linear distances between the IAN canal to the buccal cortex (a, $a^{\dag}$ and $a^{\ddag}$), from the IAN canal to the alveolar crest (b and $b^{\dag}$) and the anterior margin ($b^{\ddag}$) and finally the buccal cortical thickness (c, $c^{\dag}$ and $c^{\ddag}$) were measured at three reference planes (VP, OP and HP). Results: On the left side, the average distance of a, b and c were 7.12, 15.96 and 3.60 mm on the VP plane, respectively. On the OP, the distance of $a^{\dag}$, $b^{\dag}$ and $c^{\dag}$ was 6.11, 8.83 and 2.63 mm. For the HP, the distance of $a^{\ddag}$, $b^{\ddag}$ and $c^{\ddag}$ was 4.84, 10.11 and 2.30 mm. On the right side, the distance of a, b and c, on the VP, was 7.10, 16.13 and 3.42 mm, respectively. On the OP, the distance of $a^{\dag}$, $b^{\dag}$ and $c^{\dag}$ was 4.77, 8.75 and 2.68 mm. On the HP, the distance of $a^{\dag}$, $b^{\dag}$ and $c^{\ddag}$ was 4.55, 9.84 and 2.38 mm. Regarding the difference between genders, the distance in male's was longer than female's on the VP (p=0.019), and was thicker in males than females on the HP (p=0.002). Conclusion: The CBCT data provided accurate information about the location and course of the IAN.

• The Korean Journal of Physiology
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• v.19 no.2
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• pp.227-232
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• 1985

Previously, we had reported that the electrical stimulation of peripheral nerve with stimlatory parameters of 20 V strength and 2 Hz frequency for 60 min resulted in reducing the pain reaction. The present study was performed to evaluate if the pain reaction was affected by the peripheral nerve stimulation with different stimulatory parameters in the decerebrated cat. The flexion reflex was used as an index of the pain reaction. The reflex was elicited by stimulating the sural nerve (stimulus strength of 20 $V\;\times\;0.5$msec) and recorded as a compound action potential from the motor nerve innervated to the posterior biceps femoris muscle. The common perneal nerve was selected as a peripheral nerve on which the electrical stimulation of various intensities and frequencies was applied. The results are summarized as follows : 1) The peripheral nerve stimulation with 100 mV strength, regardless of frequencies, did not affect the pain reaction induced by the sural nerve stimulation. 2) When the stimulus of 1V intensity and slow frequency (2 Hz) was applied to the peripheral nerve for 30 min or 60 min, the pain reaction was significantly reduced comparing to the control. However, this reduced pain reaction by the peripheral nerve stimulation was not reversed by the injection of naloxone (0.02 mg/kg) 3) High frequency stimulus (60 Hz) of 1V intensity for 30 or 60 min did not show any effects of affecting the pain reaction. These results suggest that the stimulus of relatively high intensity (at least 1V) and low frequency (2 Hz) is needed to elicite the analgesic effect by the peripheral nerve stimulation. By the 1V stimulus, $A\delta$ nerve fiber is activated. Therefore, an $A\delta$ or smaller nerve fibers must be activated for showing analgesia by the peripheral nerve stimulation. However, the mechanism of analgesia by the $A\delta$ nerve activation alone was not related to the endogeneous morphine system since the reduced pain reaction by the $A\delta$ fiber activation alone was not reversed by the treatment of naloxone.

• The korean journal of orthodontics
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• v.25 no.1 s.48
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• pp.101-110
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• 1995

The purpose of this study was to observe the tissue response to the orthodontic force applied immediately after buccal horizontal subapical osteotomy of maxilla. Five mongrel cats weighing about 2.5 Kg were used for this experiment. The left upper canine and premolar of each cat served as a experimental side and the right ones as a control side. On the experimental side, a 100gm orthodontic force was applied between the upper canine and premolar immediately after the osteotomy. On the control side, the same orthodontic force was applied without the osteotomy. After 7days, the experimental animals were sacrificed. The results were as follows: 1. In the pressure zones of the experimental group, significant increase of osteoclasts and direct resolution along the alveolar bone surface was observed as compared with those of the control group. 2. In the pressure 2ones of the experimental group, a less extensive hyalinized zone was observed than those of the control group. 3. In the pressure zones of both group, no root resorption was found. 4. Tn the tension zones of the experimental group, new bone deposition increased along the alveolar bone surface as compared with those of the control group. In conclusion, the results suggest the possibility that early orthodontic treatment after orthognathic surgery may have some benefits if the stability of the repositioned segment at surgery is secured.

• Journal of Korean Classical Literature and Education
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• no.15
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• pp.329-353
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• 2008

Tasan Jeong Yak-yong is great scholar, who makes a synthesis of Sil-hak[實學, Practical Science of Korea], reformer of society, and a poet in the Joseon Dynasty. He expressed contradiction and conflict of those days by intellectual language, and reperceived basic ideology of the Joseon society. Also he theorized dissatisfaction of the people about those days and its system as form of religion. We can divide Tasan's life into two times. The first part is his ages 16~39 in the period of Jeong-jo(1777~1800). The second part is in the period of Sun-jo(1801~1834). In this period, he was exiled into Gang-jin for 17 years. After banishment, he lived a quiet life for the rest of his life in his hometown. His allegoric poetry were written in this second period. The special feature of allegoric poetry is strong satire. An allegory would be that is 'king's ear', which the barber has sight, or the barber's voice, which has divulged king's secret among the bamboos. Otherwise it would be that is the sound 'king's ear is donkey's ear' in the bamboos. This sound is divulging of the true donkey's ear. It doesn't travel to audiences, but travels trough wind in the bamboos. The narration exists just as story that barber can't stand to keep silence about king's secret. There are exposure of true and critical motive as allegoric expression. Tasan's allegoric poetry stand on the basis of his love for the people. Also there reveals his thought deeply with an enormous amount of reading and self-communion. Moreover there are his warm mind with his sharp insight in which captures alive lives as allegoric materials. Most of allegoric poetry satirize actuality of those days to make an excuse for external distinguishing marks of animals and plants. However Tasan's poetry are different from them. After he grasped serious problems from his contemporary actuality, and then choosed allegoric media to express correctly. Because he grasped the special features of lives after minute observation, he could exposure controversial point of the actual. His sharp insight was not limited to allegoric media. He noticed his period and the current of his society sensitively. It made his allegoric poetry as important materials to make us to know the condition of the people in the Joseon Dynasty. Tasan's allegoric poetry is inherited by Baek Seok[白石, 1912~1995] as regular juvenile literature. Baek Seok's juvenile stories are the results of expansion and transition for Tasan's allegoric poetry. Allegoric poetry was the shout of barber to prosecute about social irregularities and contradiction, and the sound of the bamboos to travel moaning of the people in the past. Now allegoric poetry create new emotion to make us to speculate ourselves with our surrounding. This changes are caused by special feature of allegoric poetry as a form to reflect our general lives.

• Journal of Microbiology and Biotechnology
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• v.8 no.2
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• pp.158-164
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• 1998

Crystal structural analyses of the API-TLCK complex revealed that the ${\epsilon}$-amino group (NZ) of the lysyl part of TLCK forms hydrogen bonds with OD1 of $Asp^225$ which is a substrate specificity determinant of API, OG of $Ser^214$, O of $Ser^214$, OG1 of $Thr^189$, and O of $Thr^189$ l89/. The ${\beta}$-carboxyl oxygen of $Asp^225$ forms hydrogen bonds with the NE1 of $Trp^182$. From these observations, it is thought that besides $Asp^225$, $Thr^189$, $Ser^214$, and $Trp^182$ may also contribute to the steric specificity for lysine and high proteolytic activity of API. The side-chain hydroxyl groups of $Thr^189$ and $Ser^214$ were removed to elucidate the role of these hydrogen bonds in the $S_1$-pocket. The $k_{cat}$/$K_m$ of T189V, S214A, and T189V.S214A were decreased to 1/4, 1/3, and 1/46, respectively, of the value for native API. The decreased activities were mainly due to the increase of $K_m$. The CD and fluoroscence spectra of the three mutants were similar to those of wild-type API. With regards to the kinetic parameters ($K_i\;and\;k_2$) of mutants for the reaction involving TLCK and DFP, $k_2$decreased by increase of $K_1$ only. These results suggest that the decreased catalytic activity of these mutants is caused by the partial loss of the hydrogen bond network in the $S_1$-pocket. On the other hand, the similarity of enzymatic properties between W182F and the native enzyme suggests that the hydrogen bond between OD2 of $Asp^225$ and NE1 of $Trp^182$ is not directly related to the reaction of $Asp^225$ with the substrate.

• The Korean Journal of Physiology
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• v.22 no.2
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• pp.231-243
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• 1988

This study was performed to investigate the mechanism of changes in arterial blood pressure, as a typical example of somatosympathetic reflex, induced by activation of muscular afferent nerves. Cats were anesthetized with ${\alpha}-chloraloae$ (60 mg/kg, i.p.). Afferent fibers in muscle nerve were activated by various method muscle contraction, electrical stimulation of muscle nerves, intraarterial injection of some algesic substances and noxious mechanical stimulation etc-and the evoked changes in arterial blood pressure were monitored. The effects of intravenous or direct spinal administration of morphine on the changes in arterial blood pressure induced by activation of the muscle afferent fibers were observed and also the effects of spinal lesions made in the $L1{\sim}L3$ spinal cord on them were studied to identify the ascending spinal pathways of the somatosympathetic reflexes. Followings are the results obtained. 1) The stimulation of medial gastrocnemius nerve under non-paralyzed condition with C-strength, low frequency (lower than 20 Hz) stimuli elicited a depressor response and a pressor response was elicited with C-strength, high frequency stimuli, of which the maximal response was observed at 100 Hz stimulation. 2) When the animal was paralyzed, depressor response to stimulation of the medial gastrocnemius nerve was observed with C-strength, $0.5{\sim}5Hz$ stimuli although the amplitude of the depressor response was decreased. The maximal pressor response was observed during stimulation with C-strength, $20{\sim}100Hz$ stimuli. 3) Intraarterial injection of some algesic substances induced marked pressor responses while noxious mechanical stimulation of the medial gastrocnemius muscle was not enough to elicit any significant changes (larger than 10 mmHg) in arterial blood pressure. 4) Systemically administered morphine (2 mg/kg) lowered the arterial blood pressure immediately and persistently and it was reversed by administration of naloxone. Direct spinally administered morphine did not elicit any changes. 5) The pressor response elicited by the activation of muscle afferent nerves was strengthened by systemic morphine administration while the depressor response tended to decrease. 6) Morphine administered on the spinal cord directly, decreased pressor response but did not change depressor response. From the above results it is concluded that there are separate groups of afferent nerves in the medial gastrocnemius nerve, which elicit pressor and depressor responses and the spinal ascending pathways of them are also separated from each other.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.400-407
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• 2016

The purpose of this study is to propose a useful method of solving the problem of thermal stability in surge protection devices (SPDs). First of all, the existence of the problem in the developed SPDs was confirmed by experiment. After analyzing the problem, a useful method of solving it is proposed and implemented. An experiment is performed to verify the performance of the implemented device. The results of this study are as follows; it is revealed that the problem of the thermal stability results from the varistor, one of the components in the SPD. A varistor with a built-in thermal fuse is applied to the SPD for the purpose of solving the problem. The experimental results confirmed that the thermal stability was improved by replacing the varistor. As a result of this study, the reliability of radar control units is enhanced and the probability of malfunction is reduced.

• The Korean Journal of Pharmacology
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• v.17 no.1 s.28
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• pp.9-15
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• 1981

Aconiti tuber butanol fraction, which is isolated from the chloroform insoluble and water soluble extract of Aconitum volubile, has been recently known to have a potent positive inotropic effect in the isolated cardiac muscle preparations of various animals. The positive inotropic mechanism of Aconiti tuber butanol fraction, in relation with the external calcium, was studied using the isolated cat papillary muscle. The positive inotropic effect was dependent on the calcium concentration in the nutrient medium, and a synergistic relation could be demonstrated between Aconiti tuber butanol fraction and the external calcium. The inotropic effect of $10^{-4}g/ml$ of Aconiti tuber butanol fraction was equivalent to that of 0.06mM of calcium in the medium. After the treatment with a calcium influx inhibitor, Verapamil$(2{\pm}10^{-7}-10^{-6}M)$, the contractile force of the papillary muscle was markedly inhibited. In these preparations, Aconiti tuber butanol fraction restored the decreased contractility in a dose-dependent manner. It was suggested that the positive inotropic effect of Aconiti tuber butanol fraction might be related with the stimulating action on the calcium influx through the slow inward calcium channels in the cardiac cell membrane. In contrast with digitalis cardiac glycoside, Aconiti tuber butanol fraction infused intravenously into the anesthetized rabbit decreased the systemic arterial blood pressure and increased the carotid blood flow, but produced no prominent changes in the heart rate.

• Journal of the Korean Chemical Society
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• v.43 no.5
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• pp.578-588
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• 1999

The purpose of this study is to develope the more effective chemistry teaching strategy through analyzing the demanded cognitive levels of contents in high school chemistry I textbooks and the cognitive levels of students who learn these textbooks. For this purpose, the levets of cognitive development stages of 821 second grade students of high schools in Seoul City were anaIyzed using the GALT short version test. The demanded cognitive levels of understanding the contents of chemistry I textbooks in high school were analyzed using the curriculum analysis taxonomy developed by CSMS (Concept in Secondaly Mathematics and Science) program of the Great Britain. The resuIts showed that the proportion of students in the concrete operational stage, the transition stage, and the formal operational stage was l0.7%, 43.0% and 46.3%, respectively. The demanded levels of textbook contents were mostly the early formal operational stages. The concepts demanded the level of the late formal operational stage were 'atomic and molecular weight', 'stoichiometry of chemical reaction', and 'periodic properties of elements'. The results will be helpful for teachers in knowing what concepts are difficult for students to understand and in planning strategies for teaching those concepts. To demonstrate the application of the results obtained in this study, an example of developing teaching strategy which includes the adjustment of cognitive level of contents was shown.

• Korean Journal of Medicinal Crop Science
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• v.26 no.4
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• pp.271-280
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• 2018

Background: Astragalus membranaceus is a well known oriental medicinal herb. The polysaccharides of the aboveground parts (AMA) and the radix (AMR) of A. membranaceus are the most important functional constituents. Methods and Results: The aim of this study was to determine the effects of AMA and AMR on the oxidative damage induced in the skeletal muscle of rats subjected to exhaustive exercise. Sprague-Dawley rats were randomly divided into exercise and non-exercise groups; in the groups receiving the test compounds, AMA and AMR were administered orally for 30 days. Skeletal muscle samples were collected from each rat after running to exhaustion on a treadmill to determine the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) and the concentation of malondialdehyde (MDA). The antioxidant enzyme activities of SOD and GSH-Px of skeletal muscle of AMA- and AMR-treated groups were significantly higher than those of the control and commercial sports drink (SPD)-treated groups in exhaustive exercise rats. In addition, MDA concentrations in the skeletal muscle of the AMA- and AMR-treated groups were significantly lower than those of the control and SPD-treated groups. In the present study, the effects of AMA and AMR on exercise endurance capacity were also evaluated in mice subjected to a swimming exercise test. AMA and AMR supplementation prolonged the swimming time of mice and enhanced exercise endurance capacity. AMA and AMR possess the ability to retard and lower the production of blood lactate, and prevent the decrease of serum blood glucose. Conclusions: These results showed that, AMR and AMA exerted beneficial effect in mice, increasing the activity of the antioxidant systems and inhibiting oxidative stress induced by exhaustive exercise. The compounds improved exercise performance and showed anti-fatigue effects against exhaustive exercise.