• 제목/요약/키워드: the first half of the 20C

검색결과 67건 처리시간 0.025초

한국(韓國)의 간석지(干潟地) 분포(分布) (Spatial Distribution of Tidal Flats in Korea)

  • 조명희;조화룡
    • 한국지역지리학회지
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    • 제3권2호
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    • pp.195-208
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    • 1997
  • 1910년대 지형도와 1990년대 지형도 및 위성영상을 기본도로 하여 한국의 각 지역별 간석지 분포와 간척 현황을 GIS로서 계량하고 지역별 간석지 발달조건을 고찰했다. 그 결과 우리나라 간석지 자원은 1910년대 이후 간척된 것을 포함하여 약 $3,800km^2$이고 전남 서해안, 경기만, 아산만, 전남남해안, 군산만, 천수만, 경남부산해안 순으로 넓게 형성되어 있으며, 현재 공사중인 것까지 합하면 50% 이상 간척되고 있다. 간석지 발달조건의 측면에서 경기 아산만은 모든 조건이 고루 갖추어져 있고, 군산만은 육상퇴적물 공급체계가, 전남 해안은 해안선 조건이 각각 두드러지게 양호하여 간석지가 발달했다. 군산만을 사례로 간석지 발달의 경년변화를 살펴본 결과 간석지 모양은 계속 변해가고 있으며, 면적이 조금씩 늘고 있다. 그러나 20C 전반부에는 면적증가율이 비교적 높은 데 비하여 후반부에는 훨씬 낮아져 거의 정체상태에 있는 것으로 나타났다.

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방사선 조사에 의한 DNA Double Strand Breaks의 생성 및 회복에 미치는 인삼 알칼로이드 분획의 효과 (The Effects of Alkaloid Fraction of Korean Ginseng on the Radiation-Induced DNA Strand Breaks)

  • 조철구;김태환;류성렬;고경환;김미숙;김정희;김성호;윤형근;지영훈
    • Radiation Oncology Journal
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    • 제13권2호
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    • pp.113-120
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    • 1995
  • Purpose : To investigate the effect of alkaloid fraction from Korean ginseng on radiation-induced DNA double strand breaks (dsb) formation and repair in murine lymphocytes Materials and Methods : We used the neutral filter elution technique to assay $^{60}Co\;{\gamma}$ ray-induced DNA double strand breaks formation and repair in C57BL/6 mouse spleen lymphocytes for evaluating the dose-response relationship in the presence of alkaloid fraction as a radioprotective agent. The lymphocytes were stimulated with Phytohemagglutinin (PHA, 2 u g/ml) to label $^3[H]-thymidine.$ Isotope-labelled lymphocytes in suspension were exposed to 100 Gy at $0^{\cdot}C$ in the alkaloid fraction-treated group and elution procedure was performed at PH 9.6. The extents of formation of radiation-induced DNA double strand breaks and repair were compared respectively via strand scission factor (SSF) and relative strand scission factor (RSSF). Results: Alkaloid fraction reduced the formation of double strand breaks with dose modification factor of 2 15, compared to control group Rejoining of DNA dsb appeared to take place via two components. The first fast component was completed within 20.4 minutes, but the second slow component was not completed until 220.2 minutes after irradiation. About $30\%$ of dsb formed by irradiation was ultimately unrejoined despite the administration of alkaloid fraction. The administration of alkaloid fraction had a great effect on the second slow component of repair; the half-time of fast component repair was not changed, but that of slow component was 621.8 minutes. Conclusion: Neutral filter elution assay Proved to be a very effective method to quantitate the extents of DNA dsb formation and its repair. By using this technique, we were able to evaluate the efficiency of alkaloid fraction from Korean ginseng as a valuable radioprotector. Alkaloid fraction can be used prophylactically to prevent or ameliorate the severe radiation damages in workers and neighbors around the atomic power plants. For more refined study, however, more advanced purification of alkaloid fraction wil be needed in the near future.

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그룹 이동성을 가지는 모바일 사용자들 간의 효율적인 데이터 공유를 위한 클러스터 기반 그룹 라우팅 기법 메커니즘 (Cluster-Based Routing Mechanism for Efficient Data Delivery to Group Mobile Users in Wireless Ad-Hoc Networks)

  • 유진희;한경아;정다희;이형준
    • 한국통신학회논문지
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    • 제38C권11호
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    • pp.1060-1073
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    • 2013
  • 본 논문에서는 무선 애드혹 네트워크상에서 그룹 이동성이 있는 모바일 사용자들을 beacon 메시지 수신 상태 정보만을 이용하여 분산적인 방법으로 온라인 클러스터링 하는 기법과 그룹 내로 데이터를 효과적으로 전달하기 위한 클러스터 헤드 노드를 선정하는 기법을 제시하고, 선정한 클러스터 헤드 노드를 통해 그룹 내부로 데이터를 전달할 수 있는 효율적인 그룹 라우팅 기법을 제안한다. ns-2를 이용하여 518개의 정적 노드와 20개의 동적 노드로 구성된 네트워크에 대해 성능 평가한 결과, 평균적으로 96 %의 높은 클러스터링 정확도를 보임을 확인할 수 있었다. 또한 그룹의 개념 없이 개별적으로 모바일 노드들로 일대일 라우팅을 한 경우에 비해 제안한 클러스터 기반 라우팅 기법을 사용했을 경우, 총 라우팅 비용이 1/20 정도로 감소하였으며, 그룹의 개념은 존재하지만 임의의 모바일 노드를 통해 intra-cluster 라우팅 했을 경우에 비해, 제안한 클러스터 헤드 노드를 통해 라우팅 했을 경우, 라우팅 비용이 평균적으로 1/2 정도로 감소함을 확인할 수 있었다.

4-Tert-Octylphenol의 랫드에서의 조직분포 및 독성동태에 관한 연구 (Tissue Distribution and Toxicokinetics of 4-Tert-Octylphenol in Rats)

  • 강미경;안미령;정혜주;최선옥;최홍석;양지선;이용복;유태무;손수정
    • Toxicological Research
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    • 제20권3호
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    • pp.195-203
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    • 2004
  • 4-Tert-Octylphenol (OP) is a surfactant additive widely used in the manufacture of a variety of detergents and plastic products. OP can disrupt endocrine function in humans and animals. This study was carried out to obtain toxicokinetic parameters of OP in male Sprague-Dawley (SD) rats. Male rats were administered with OP by single oral application of 200 mg/kg body weight. Blood, urine and tissues samples were taken at several time intervals after administration. Analysis of samples for OP was performed by column-switching high performance liquid chromatography (HPLC). In addition, we exam-ined tissue distribution and accumulation of OP after single oral application of 50, 100, and 200 mg/kg, single intravenous injection of 1, 5 and 10 mg/kg or daily application of 50 mg/kg for 14 consecutive days. After single oral administration of 200 mg/kg, Cmax of 213 $\pm$ 123 ng/ml was reached within the first 1.3 hr (Tmax) in the plasma. AUC was calculated for 1,333$\pm$484 ngㆍhr/ml. The final elimination half-life of plasma was longer than that of urine, but urinary clearance was lower than oral. A very small fraction of OP (Fe < 0.0017%) was excreted in urine within 24 hr. These results indicated that the major excretion route of OP was not urine. The mean maximal tissue distribution of OP was obserbed at 6 hr after treatment and slowly decreased time-dependently. High OP concentrations were detected in fat at 24 hr. The OP in fat was slowly released with longer elimination half-life and lower clearance than that of other tissues. OP was not accumulated in the liver following single oral application but 14-day oral treatments resulted in two-fold accumulation. It was probably due to the saturation of detoxification pathways. On the other hand, the mRNA expression of cytochrome P450 isoforms except CYP2C11 was not affected by OP at any dose. The expression of CYP2C11 mRNA decreased in a dose-dependent manner. This result suggests that OP changes expression of the male-specific cytochrome P450 isoforms in rat liver, and these changes are closely related to the toxic and estrogenic effect of OP.

동치미의 저장성 향상을 위한 열수 담금 및 염혼합물 첨가의 병용효과 (Compined Effect of Brining in Hot Solution and Salts Mixture Addition for Improvement of Storage Stability of Dongchimi)

  • 강근옥;구경형;김우정
    • 한국식품영양과학회지
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    • 제20권6호
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    • pp.559-564
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    • 1991
  • 동치미의 저장성 향상효과를 보기 위하여 동치미 제조시와 발효시 열처리 및 염 첨가 등을 같이 행하여 >$25^{\circ}C$에서 발효시키면서 이들이 동치미의 pH, 산도, 텍스쳐, 환원당 및 관능적 품질 변화에 미치는 영향을 측정하였다. 그 결과 열처리와 무기산염 및 인산염을 같이 처리한 방법 B 및 C 처리구가 대조구에 비해 약 2~2.5배의 저장 연장 효과를 보였으며 총산도에서는 열처리 및 KCI, $CaCl_2 첨가를 같이한 방법 A구가 가장 낮은 함량을 나타내었다. 텍스쳐에서는 대체로 대조구에 비해 처리구의 견고성이 높았으며 환원당은 열수담금을 했던 방법 A, B, C는 담금초기부터 환원당의 농도가 높았으나 발효가 진행되면서 감소하여 대조구와 반대현상을 보여주었다. 한편 동치미의 관능적 평가에서는 처리구의 품질이 대조구보다 더 신선하여 같은 발효일에서 생무우내와 생무우맛은 많은 반면 신내와 신 맛은 적은 것으로 나타났다.

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원산지표시위반 수입물품 유통으로 인한 피해의 연구 (A Study on Damage from the Distributed Imports with the Infraction of the Country of Origin Indication)

  • 정재완
    • 무역상무연구
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    • 제50권
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    • pp.251-275
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    • 2011
  • This study represents the current situation on the Korean Government's investigation into the imports with the infraction of the country of origin indication law, showing how much those imports affect the purchasers as well as the domestic competitors in Korea. According to the HS 4 unit, the range of imports with the country of origin indication should be 55.2% of all imports, but it turned out there were actually 87.6% of them, according to the number of the import declarations in the first half year of 2010. The government's investigation on the infraction of the country of origin indication is conducted in the stages of customs and distribution into market. As a result of recent 4 years government's investigation into the imports with the infraction of the country of origin indication, the rate of inspection was averagely 3.6% of the reported number of imports in the stage of customs, the rate of the infraction of the country of origin indication cases was 0.14% of the total reported number, and 3.85% of the total actually inspected number. The investigation in the stage of distribution was below 20% level of the stage of customs inspection, on the number of caught cases basis. A survey of 4 categorized imports such as Watches, Tools, Glasses frames, and Clothes, which are assumed to happened frequently with the infraction cases, shows that the decreased sales rate of the domestic competitors was averagely 18.8% and the extent of the damage on consumers was 34.7% of the purchased prices, with both rates resulted from the investigation in the stage of distribution into market.

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아톨바스타틴과 니페디핀의 약물동태학적 상호작용 (Pharmacokinetic Interaction Between Atorvastatin and Nifedipine)

  • 문홍섭;최준식
    • 한국임상약학회지
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    • 제20권1호
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    • pp.25-29
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    • 2010
  • The purpose of this study was to investigate the effect of atorvastatin on the pharmacokinetics of nifedipine (6 mg/kg) after oral administration of nifedipine with or without atorvastatin (0.5 and 2.0 mg/kg) in rats, and also was to evaluate to the effect of atorvastatin on the CYP3A4 activity. The 50% inhibiting concentration ($IC_{50}$) values of atorvastatin on CYP3A4 activity is 46.1 ${\mu}M$. Atorvastatin inhibited CYP3A4 enzyme activity in a concentration-dependent manner. Coadministration of atorvastatin increased significantly (p<0.05, 2.0 mg/kg) the plasma concentration-time curve (AUC) and the peak concentration ($C_{max}$) of nifedipine compared to the control group. The relative bioavailability (RB%) of nifedipine was increased from 1.15- to 1.37-fold. Coadministration of atorvastatin did not significantly change the terminal half-life ($T_{1/2}$) and the time to reach the peak concentration ($T_{max}$) of nifedipine. Based on these results, we can make a conclusion that the significant changes of these pharmacokinetic parameters might be due to atorvastatin, which possesses the potency to inhibit the metabolizing enzyme (CYP3A4) in the liver and intestinal mucosa, and also inhibit the P-glycoprotein (P-gp) efflux pump in the intestinal mucosa. It might be suggested that atorvastatin altered disposition of nifedipine by inhibition of both the first-pass metabolism and P-glycoprotein efflux pump in the small intestine of rats. In conclusion, the presence of atorvastatin significantly enhanced the oral bioavailability of nifedipine, suggesting that concurrent use of atorvastatin with nifedipine should require close monitoring for potential drug interation.

Effects of Hydrocortisone on the Pharmacokinetics of Loratadine after Oral and Intravenous Loratadine Administration to Rats

  • Choi, Jun-Shik;Choi, In;Burm, Jin-Pil
    • Biomolecules & Therapeutics
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    • 제17권2호
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    • pp.205-210
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    • 2009
  • The present study investigated the effects of hydrocortisone on the pharmacokinetics of loratadine in rats after intravenous and oral administration. A single dose of loratadine was administered either orally (4 mg/kg) or intravenously (1 mg/kg) with or without oral hydrocortisone (0.3 or 1.0 mg/kg). Compared to the control group (without hydrocortisone), after oral administration of loratadine, the area under the plasma concentration-time curve (AUC) was significantly increased by 30.2-81.7% in the presence of hydrocortisone (p<0.05). The peak plasma concentration ($C_{max}$) was significantly increased by 68.4% in the presence of 1.0 mg/kg hydrocortisone after oral administration of loratadine (p<0.05). Hydrocortisone (1.0 mg/kg) significantly increased the terminal plasma half-life ($t_{1/2}$) of loratadine by 20.8% (p<0.05). Consequently, the relative bioavailability of loratadine was increased by 1.30- to 1.82-fold. In contrast, oral hydrocortisone had no effects on any pharmacokinetic parameters of loratadine given intravenously. This suggests that hydrocortisone may improve the oral bioavailability of loratadine by reducing first-pass metabolism of loratadine, most likely mediated by P-gp and/or CYP3A4 in the intestine and/or liver. In conclusion, hydrocortisone significantly enhanced the bioavailability of orally administered loratadine in rats, which may have been due to inhibition of both CYP 3A4-mediated metabolism and P-gp in the intestine and/or liver by the presence of hydrocortisone.

The use of SMA wire dampers to enhance the seismic performance of two historical Islamic minarets

  • El-Attar, Adel;Saleh, Ahmed;El-Habbal, Islam;Zaghw, Abdel Hamid;Osman, Ashraf
    • Smart Structures and Systems
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    • 제4권2호
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    • pp.221-232
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    • 2008
  • This paper represents the final results of a research program sponsored by the European Commission through project WIND-CHIME ($\underline{W}$ide Range Non-$\underline{IN}$trusive $\underline{D}$evices toward $\underline{C}$onservation of $\underline{HI}$storical Monuments in the $\underline{ME}$diterranean Area), in which the possibility of using advanced seismic protection technologies to preserve historical monuments in the Mediterranean area is investigated. In the current research, the dynamic characteristics of two outstanding Mamluk-Style minarets, which similar minarets were reported to experience extensive damage during Dahshur 1992 earthquake, are investigated. The first minaret is the Qusun minaret (1337 A.D, 736 Hijri Date (H.D)) located in El-Suyuti cemetery on the southern side of the Salah El-Din citadel. The minaret is currently separated from the surrounding building and is directly resting on the ground (no vaults underneath). The total height of the minaret is 40.28 meters with a base rectangular shaft of about 5.42 ${\times}$ 5.20 m. The second minaret is the southern minaret of Al-Sultaniya (1340 A.D, 739 H.D). It is located about 30.0 meters from Qusun minaret, and it is now standing alone but it seems that it used to be attached to a huge unidentified structure. The style of the minaret and its size attribute it to the first half of the fourteenth century. The minaret total height is 36.69 meters and has a 4.48 ${\times}$ 4.48 m rectangular base. Field investigations were conducted to obtain: (a) geometrical description of the minarets, (b) material properties of the minarets' stones, and (c) soil conditions at the minarets' location. Ambient vibration tests were performed to determine the modal parameters of the minarets such as natural frequencies and mode shapes. A $1/16^{th}$ scale model of Qusun minaret was constructed at Cairo University Concrete Research Laboratory and tested under free vibration with and without SMA wire dampers. The contribution of SMA wire dampers to the structural damping coefficient was evaluated under different vertical loads and vibration amplitudes. Experimental results were used along with the field investigation data to develop a realistic 3-D finite element model that can be used for seismic risk evaluation of the minarets. Examining the updated finite element models under different seismic excitations indicated the vulnerability of such structures to earthquakes with medium to high a/v ratio. The use of SMA wire dampers was found feasible for reducing the seismic risk for this type of structures.

서울시내 중고등학교 결핵이환학생에 대한 결핵관리실태 및 지식에 관한 조사연구 (A Study on Knowledge and Disease Management of Tuberculosis by Themselves of Tuberculosis Patients Among the Middle and High School Students in Seoul.)

  • 도성숙
    • 한국보건간호학회지
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    • 제1권1호
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    • pp.32-44
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    • 1987
  • The purpose of this survey was to find out the knowledge and the disease management of the Tuberculosis patients by themselves among the first grade middle and high school students in Seoul city during the period of June 15-July 19, 1986. Questionaires were used to collect the data and were analysed from answers of 188 students at the 113 schools. The results were as follows: 1. The ages of the students were distributed as follows: in middle school, 13 years old was $70.0\%$. 14 years old, $20.0\%$, and 15 years old, $6.7\%$. In high school, 16 years old was $66.5\%$, 17 years old, $18.4\%$, and 15 years old, $10.1\%$. 2. In X-ray mass examination by school, the rate of execution was $50.4\%$ in middle school and $96.7\%$ in high school, and in X-ray mass examination by student, it was $50.1\%$ in middle school and $97.3\%$ in high school. 3. The prevalence of Tuberculosis among the middle school students was $00.3\%$and high school students, $0.15\%$. 4. Of the total, $77.1\%$ of the respondents did not realized Tuberculosis bdore X-ray mass examination 5. The perfect cure rate of the respondents was $52.7\%$. 6. General characteristics of the respondents: a. The educational background was varied as follows: of the total $47.9\%$ of the fathers had the level of high school education and $37.2\%$ of the mothers had the level of middle school education. The educational background of the parents had no statistical significant to the medical cure rate of Tuberculosis. (P>0.05). b. The average monthly income of the family was as follows : above five hundred thousand won was $21.8\%$, three or four hundred thousand won was $22.9\%$, and below two hundred thousand won was $10.6\%$. The most frequent family size was 5-6 persons. $(59.6)\%$. 7. The actual situation of Tuberculosis control and the variables related to the treatment: a. $69.1\%$ of the respondents wanted mental support from their surroundings. $48.7\%$ of the respondents answered that their parents or the other family helped treatment as mental supporter, b. As a medical service, $53.2\%$ of the respondents were treated at Health Center, $38.8\%$ were treated at a hospital. A medical service was statistically significant to the medical cure (P<0.01). c. Family members of $61.7\%$ of the respondents had checked chest X-ray. A X-ray examination of family was statistically significant to the medical cure (P<0.005). d. $73.9\%$ of the respondents had taken the Anti-Tuberculosis-drugs regularly. Regular taking of Anti-Tuberculosis drugs was statistically significant to the medical cure (P<0.005). e. $89.4\%$ of the respondents had received a regular examination during the treatment. A regular examination was statistically significant to the medical cure (P<0.05). f. The period of perfect cure was that $50.0\%$ of the respondents took from half a year to one year, $25.2\%$ took below half a year and $16.2\%$ took from one year to one year and a half. g. The rate of the respondents who abhored to let anyone know their disease was $93.1\%$. 8. Knowledge related with Tuberculosis: a .$63.3\%$ of the respondents answered that Tuberculosis is a communiable disease. b. $89.9\%$ of the respondents answered that there is a preventive method of Tuberculosis. Among them, $28.4\%$ answered that it is B.C.G. vacination. c. $96.8\%$ of the respondents belived they can be cured perfectly. d. $42.4\%$ of the perfect curer answered that they had have permanent immunity of Tuberculosis. According to the results of above study, it is desired to be practiced X-ray mass examination to the total middle school students. Nurse teachers and the responsible persons who participated to the helping of disease management to the Tuberculosis patients must make an offer knowledge of Tuberculosis to the Tuberculosis patients. And also, it will be very helpful to the cure of Tuberculosis patients if they do their best and to have a mental supporter.

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