• Title/Summary/Keyword: $S_N1$ mechanism

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Analyses of Widely Used Design Codes for Pile Foundation Using the t-z Method (t-z 방법을 이용한 말뚝기초 설계기준별 비교분석)

  • Park, Sungwon;Misra, Anil
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.10
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    • pp.33-42
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    • 2012
  • The efficiency of the current design methods for computing pile resistances is analyzed using field load-settlement tests results. Twelve load-settlement test data for drilled shafts and bored piles were obtained from the literature. These load-test data were fitted using the t-z method. Subsequently, the ultimate resistances were evaluated based upon the failure criteria from following methods: (1) the Davisson's approach and (2) settlement corresponding to 5% or 10% shaft diameter approach. The ultimate resistances for these drilled shafts and bored piles were also predicted using methods based on the design code from North America (United States, Canada), Europe, and Asia (Japan). The pile resistances determined from field load-settlement tests were compared with those calculated using the design codes. The comparisons show that most design codes predict a conservative resistance for drilled shafts and bored piles. However, in the case of drilled shafts, we find that some of the design codes can over-predict the resistance and, therefore, should be applied cautiously. This research also shows that the t-z method can be successfully used to predict the ultimate resistance and the load transfer mechanism for a single pile.

Separation and Elution Behavior of Some Iron(Ⅲ)porphyrin Complexes by Reversed-Phase Liquid Chromatography (역상 액체 크로마토그래피에 의한 Iron(Ⅲ)porphyrin 착화합물들의 분리 및 용리거동에 관한 연구)

  • Chang Hee Kang;In Whan Kim;Won Lee
    • Journal of the Korean Chemical Society
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    • v.37 no.12
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    • pp.1035-1046
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    • 1993
  • Some iron(III)porphyrin complexes were prepared, and identified by the spectroscopic methods. Elution behavior of iron(III)porphyrin complexes was investigated by reversed-phase HPLC. The optimum conditions for the separation of iron(III)porphyrin complexes were examined with respect to flow rate and mobile phase strength. These complexes were successfully separated on NOVA-PAK $C_{18}$ column using methanol / water(95/5) for $[T_pCF_3PP)Fe(R)]$ and methanol / water (98/2) for $[(P)Fe(C_6F_5)]$ as a mobile phase. It was found that these complexes were largely eluted in an acceptable range of capacity factor value ($0{\leq}logk'{\leq}1$). The dependence of the capacity factor (k') on the volume fraction of water in the binary mobile phase as well as the dependence of k' on the liquid-liquid extraction distribution ratio$(D_c)$ in methanol-water / n-pentadecane extraction system showed a good linearity. It means that the retention of iron(III)porphyrin complexes on NOVA-PAK $C_{18}$ column is largely due to the solvophobic effect. Also, there was a good linear dependence of the capacity factor(k') on the column temperature and enthalpy calculated by van't Hoff plot. From these results, it was confirmed that the retention mechanism of iron(III)porphyrin complexes in reversed-phase liquid chromatography was invariant under the condition of various temperature, and the solvophobic binding process exhibited isoequilibrium behavior.

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Immunostimulatory activity of hydrolyzed and fermented Platycodon grandiflorum extract occurs via the MAPK and NF-κB signaling pathway in RAW 264.7 cells

  • Jae In, Jung;Hyun Sook, Lee;So Mi, Kim;Soyeon, Kim;Jihoon, Lim;Moonjea, Woo;Eun Ji, Kim
    • Nutrition Research and Practice
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    • v.16 no.6
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    • pp.685-699
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    • 2022
  • BACKGROUND/OBJECTIVES: Platycodon grandiflorum (PG) has long been known as a medicinal herb effective in various diseases, including bronchitis and asthma, but is still more widely used for food. Fermentation methods are being applied to increase the pharmacological composition of PG extracts and commercialize them with high added value. This study examines the hydrolyzed and fermented PG extract (HFPGE) fermented with Lactobacillus casei in RAW 264.7 cells, and investigates the effect of amplifying the immune and the probable molecular mechanism. MATERIALS/METHODS: HFPGE's total phenolic, flavonoid, saponin, and platycodin D contents were analyzed by colorimetric analysis or high-performance liquid chromatography. Cell viability was measured by the MTT assay. Phagocytic activity was analyzed by a phagocytosis assay kit, nitric oxide (NO) production by a Griess reagent system, and cytokines by enzyme-linked immunosorbent assay kits. The mRNA expressions of inducible nitric oxide synthase (iNOS) and cytokines were analyzed by reverse transcription-polymerase chain reaction, whereas MAPK and nuclear factor (NF)-κB activation were analyzed by Western blots. RESULTS: Compared to PGE, HFPGE was determined to contain 13.76 times and 6.69 times higher contents of crude saponin and platycodin D, respectively. HFPGE promoted cell proliferation and phagocytosis in RAW 264.7 cells and regulated the NO production and iNOS expression. Treatment with HFPGE also resulted in increased production of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, C-X-C motif chemokine ligand10, granulocyte-colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and monocyte chemoattractant protein-1, and the mRNA expressions of these cytokines. HFPGE also resulted in significantly increasing the phosphorylation of NF-κB p65, extracellular signal-regulated kinase, and c-Jun N-terminal kinase. CONCLUSIONS: Taken together, our results imply that fermentation and hydrolysis result in the extraction of more active ingredients of PG. Furthermore, we determined that HFPGE exerts immunostimulatory activity via the MAPK and NF-κB signaling pathways.

Tanshinone IIA reduces pyroptosis in rats with coronary microembolization by inhibiting the TLR4/MyD88/NF-κB/NLRP3 pathway

  • Li, Hao-Liang;Li, Tao;Chen, Zhi-Qing;Li, Lang
    • The Korean Journal of Physiology and Pharmacology
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    • v.26 no.5
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    • pp.335-345
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    • 2022
  • Pyroptosis is an inflammatory form of programmed cell death that is linked with invading intracellular pathogens. Cardiac pyroptosis has a significant role in coronary microembolization (CME), thus causing myocardial injury. Tanshinone IIA (Tan IIA) has powerful cardioprotective effects. Hence, this study aimed to identify the effect of Tan IIA on CME and its underlying mechanism. Forty Sprague-Dawley (SD) rats were randomly grouped into sham, CME, CME + low-dose Tan IIA, and CME + high-dose Tan IIA groups. Except for the sham group, polyethylene microspheres (42 ㎛) were injected to establish the CME model. The Tan-L and Tan-H groups received intraperitoneal Tan IIA for 7 days before CME. After CME, cardiac function, myocardial histopathology, and serum myocardial injury markers were assessed. The expression of pyroptosis-associated molecules and TLR4/MyD88/NF-κB/NLRP3 cascade was evaluated by qRT-PCR, Western blotting, ELISA, and IHC. Relative to the sham group, CME group's cardiac functions were significantly reduced, with a high level of serum myocardial injury markers, and microinfarct area. Also, the levels of caspase-1 p20, GSDMD-N, IL-18, IL-1β, TLR4, MyD88, p-NF-κB p65, NLRP3, and ASC expression were increased. Relative to the CME group, the Tan-H and Tan-L groups had considerably improved cardiac functions, with a considerably low level of serum myocardial injury markers and microinfarct area. Tan IIA can reduce the levels of pyroptosis-associated mRNA and protein, which may be caused by inhibiting TLR4/MyD88/NF-κB/NLRP3 cascade. In conclusion, Tanshinone IIA can suppress cardiomyocyte pyroptosis probably through modulating the TLR4/MyD88/NF-κB/NLRP3 cascade, lowering cardiac dysfunction, and myocardial damage.

Physico-Chemical Factors on the Growth of Cochlodinium polykrikoides and Nutrient Utilization (Cochlodinium polykrikoides의 성장에 미치는 물리$\cdot$화학적 요인과 영양염 이용)

  • KIM Hyung Chul;LEE Chang Ku;LEE Sam Geun;KIM Hak Gyoon;PARK Chung Kil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.34 no.5
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    • pp.445-456
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    • 2001
  • In the 1990s, Cochlodinium polykikoides red tide has been annually occurred in the southern coast of Korea and caused the mass damage to the fisheries with a huge amount of economic loss. The present study was done to establish the biological foundation for the elucidation of the mechanism of C. polykikoiaes red tide. The growth response of C. polykikoides to physico-chemical factors such as temperature, salinity, pH, and light intensity were examined using axenic cultures to evaluate the relative importance of these factors on the dynamics of natural populations, It was found that the highest growth conditions were $25^{\circ}C,\;40\%_{\circ}$, pH 7.5, and 7,500 lux, respectively. The tolerable salinity range of growth was relatively wide at an optimum temperature and was reduced to a much narrower range at a sub-optimum temperature. These findings indicate that C. polykikoides is an eurythermal and euryhaline organism. The organism demanded higher light intensity and oceanic pH narrow in its growth. C. polykikoides utilize inorganic nutrients, such as nitrate and ammonium as N, and phosphate as P. The nutritional requirements of C. polykikoides were $40{\mu}M$ for nitrate, $50{\mu}M$ for ammonium, and $5{\mu}M$ for phosphate. The half saturation constant (Ks) for growth was $2.10{\mu}M$ for nitrate, $1.03{\mu}M$ for ammonium, and $0.57{\mu}M$ for phosphate. These values were comparatively smaller than those of other dinoflagellates reported previously. We confirmed that the organism is characterized as an eutrophic species. However, ammonium Ks value is smaller than that of other eutrophic species, This result indicates that C. polykikoides red tide may outbreak in the waters which eutrophication is in progress rather than eutrophicated waters. C. polykikoides preferred ammonium better than nitrate as a nitrogen source when in a growth stage, Therefore, our results indicate that ammonium is more important nutrient on the growth of the organism in comparison with other inorganic nutrients and C. polykikoides red tide is related with the increased ammonium concentration in the coastal waters.

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Regulatory Mechanism of Radiation-induced Cancer Cell Death by the Change of Cell Cycle (세포주기 변화에 타른 방사선 유도 암세포 사망의 조절기전)

  • Jeong Soo-Jin;Jeong Min-Ho;Jang Ji-Yeon;Jo Wol-Soon;Nam Byung-Hyouk;Jeong Min-Za;Lim Young-Jin;Jang Byung Gon;Youn Seon-Min;Lee Hyung Sik;Hur Won Joo;Yang Kwang Mo
    • Radiation Oncology Journal
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    • v.21 no.4
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    • pp.306-314
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    • 2003
  • Purpose : In our Previous study, we have shown the main cel1 death pattern Induced by irradiation or protein tyrosine kinase (PTK) inhibitors in K562 human myeiogenous leukemic cell line. Death of the cells treated with irradiation alone was characterized by mitotic catastrophe and typical radiation-induced apoptosis was accelerated by herblmycin A (HMA). Both types of cell death were inhibited by genistein. In this study, we investigated the effects of HMA and genistein on cell cycle regulation and its correlation with the alterations of radiation-induced cell death. Materials and Methods: K562 cells In exponential growth phase were used for this study. The cells were Irradiated with 10 Gy using 6 MeV Linac (200-300 cGy/min). Immediately after irradiation, cells were treated with 250 nM of HMA or 25 $\mu$N of genistein. The distributions of cell cycle, the expressions of cell cycle-related protein, the activities of cyclin-dependent kinase, and the yield of senescence and differentiation were analyzed. Results: X-irradiated cells were arrested In the G2 phase of the cell cycle but unlike the p53-positive cells, they were not able to sustain the cell cycle arrest. An accumulation of cells in G2 phase of first ceil-cycle post-treatment and an increase of cyclin Bl were correlated with spontaneous, premature, chromosome condensation and mitotic catastrophe. HMA induced rapid G2 checkpoint abrogation and concomitant p53-independent Gl accumulation. HMA-induced cell cycle modifications correlated with the increase of CDK2 kinase activity, the decrease of the expressions of cyclins I and A and of CDK2 kinase activity, and the enhancement of radiation-induced apoptosis. Genistein maintained cells that were arrested in the G2-phase, decreased the expressions of cyclin Bl and cdc25c and cdc25C kinase activity, increased the expression of pl6, and sustained senescence and megakaryocytic differentiation. Conclusion: The effects of HMA and genistein on the radiation-induced cell death of KS62 cells were closely related to the cell cycle regulatory activities. In this study, we present a unique and reproducible model in which for investigating the mechanisms of various, radiation-induced, cancer cell death patterns. Further evaluation by using this model will provide a potent target for a new strategy of radiotherapy.

Applicability of plate tectonics to the post-late Cretaceous igneous activities and mineralization in the southern part of South Korea( I ) (한국남부(韓國南部)의 백악기말(白堊紀末) 이후(以後)의 화성활동(火成活動)과 광화작용(鑛化作用)에 대(對)한 판구조론(板構造論)의 적용성(適用性) 연구(硏究)( I ))

  • Min, Kyung Duck;Kim, Ok Joon;Yun, Suckew;Lee, Dai Sung;Joo, Sung Whan
    • Economic and Environmental Geology
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    • v.15 no.3
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    • pp.123-154
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    • 1982
  • Petrochemical, K-Ar dating, Sand Rb/Sr isotopes, metallogenic zoning, paleomagnetic and geotectonic studies of the Gyongsang basin were carried out to examine applicability of plate tectonics to the post-late Cretaceous igneous activity and metallogeny in the southeastern part of Korean Peninsula. The results obtained are as follows: 1. Bulgugsa granitic rocks range from granite to adamellite, whose Q-Ab-Or triangular diagram indicates that the depth and pressure at which the magma consolidated increase from coast to inland varying from 6 km, 0.5-3.3 kb in the coastal area to 17 km, 0.5-10 kb in the inland area. 2. The volcanic rocks in Gyongsang basin range from andesitic to basaltic rocks, and the basaltic rocks are generally tholeiitic in the coastal area and alkali basalt in the inland area. 3. The volcanic rocks of the area have the initial ratio of Sr^{87}/Sr^{86} varying from 0.706 to 0.707 which suggests a continental origin; the ratio of Rb/Sr changing from 0.079-0.157 in the coastal area to 0.021-0.034 in the inland area suggests that the volcanism is getting younger toward coastal side, which may indicate a retreat in stage of differentiation if they were derived from a same magma. The K_2O/SiO_2 (60%) increases from about 1.0 in the coastal area to about 3.0 in the inland area, which may suggest an increase indepth of the Benioff zone, if existed, toward inland side. 4. The K-Ar ages of volcanic rocks were measured to be 79.4 m.y. near Daegu, and 61.7 m.y. near Busan indicating a southeastward decrease in age. The ages of plutonic rocks also decrease toward the same direction with 73 m.y. near Daegu, and 58 m.y. near Busan, so that the volcanism predated the plutonism by 6 m.y. in the continental interior and 4 m.y. along the coast. Such igneous activities provide a positive evidence for an applicability of plate tectonics to this area. 5. Sulfur isotope analyses of sulfide minerals from 8 mines revealed that these deposits were genetically connected with the spacially associated ingeous rocks showing relatively narrow range of ${\delta}^{34}S$ values (-0.9‰ to +7.5‰ except for +13.3 from Mulgum Mine). A sequence of metallogenic zones from the coast to the inland is delineated to be in the order of Fe-Cu zone, Cu-Pb-Zn zone, and W-Mo zone. A few porphyry type copper deposits are found in the Fe-Cu zone. These two facts enable the sequence to be comparable with that of Andean type in South America. 6. The VGP's of Cretaceous and post Cretaceous rocks from Korea are located near the ones($71^{\circ}N$, $180^{\circ}E$ and $90^{\circ}N$, $110^{\circ}E$) obtained from continents of northern hemisphere. This suggests that the Korean peninsula has been stable tectonically since Cretaceous, belonging to the Eurasian continent. 7. Different polar wandering path between Korean peninsula and Japanese islands delineates that there has been some relative movement between them. 8. The variational feature of declination of NRM toward northwestern inland side from southeastern extremity of Korean peninsula suggests that the age of rocks becomes older toward inland side. 9. The geological structure(mainly faults) and trends of lineaments interpreted from the Landsat imagery reveal that NNE-, NWW- and NEE-trends are predominant in the decreasing order of intensity. 10. The NNE-trending structures were originated by tensional and/or compressional forces, the directions of which were parallel and perpendicular respectively to the subduction boundary of the Kula plate during about 90 m.y. B.P. The NWW-trending structures were originated as shear fractures by the same compressional forces. The NEE-trending structures are considered to be priginated as tension fractures parallel to the subduction boundary of the Kula plate during about 70 m.y. B.P. when Japanese islands had drifted toward southeast leaving the Sea of Japan behind. It was clearly demonstrated by many authors that the drifting of Japanese islands was accompanied with a rotational movement of a clock-wise direction, so that it is inferred that subduction boundary had changed from NNE- to NEE-direction. A number of facts and features mentioned above provide a suite of positive evidences enabling application of plate tectonics to the late Cretaceous-early Tertiary igneous activity and metallogeny in the area. Synthesizing these facts, an arc-trench system of continental margin-type is adopted by reconstructing paleogeographic models for the evolution of Korean peninsula and Japan islands. The models involve an extention mechanism behind the are(proto-Japan), by which proto-Japan as of northeastern continuation of Gyongsang zone has been drifted rotationally toward southeast. The zone of igneous activity has also been migrated from the inland in late-Cretaceous to the peninsula margin and southwestern Japan in Tertiary.

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Licochalcone C Induces Autophagy in Gefitinib-sensitive or-resistant Human Non-small Cell Lung Cancer Cells (Gefitinib-민감성 또는 내성 비소세포폐암 세포에서 Licochalcone C에 의한 자가포식 유도)

  • Oh, Ha-Na;Yoon, Goo;Chae, Jung-Il;Shim, Jung-Hyun
    • Journal of Life Science
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    • v.29 no.12
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    • pp.1305-1313
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    • 2019
  • Licochalcone (LC), isolated from the roots of Glycyrrhiza inflata has multiple pharmacological effects including anti-inflammatory and anti-tumor activities. To date, Licochalcone C (LCC) has induced apoptosis and inhibited cell proliferation in oral and bladder cancer cells, but lung cancer has not yet been studied. In addition, no study reported LCC-induced autophagy in cancer until now. The present study was designed to investigate the effect of LCC on gefitinib-sensitive and -resistant lung cancer cells and elucidate the mechanism of its action. The 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay data showed that LCC significantly inhibited cell viability in non-small cell lung cancer (NSCLC) HCC827 (gefitinib-sensitive) and HCC827GR (gefitinib-resistant) cell lines. Interestingly, Annexin V/7-aminoactinomycin D double staining and cell cycle analysis showed an apoptosis rate within about 20% at the highest concentration of LCC. LCC induced G2/M arrest by reducing the expression of the cell cycle G2/M related proteins cyclin B1 and cdc2 in NSCLC cell lines. Treatment of LCC also induced autophagy by increasing the expression of the autophagy marker protein microtubule-associated protein 1 light chain 3 (LC3) and the protein autophagy-related gene 5 involved in the autophagy process. In addition, LCC increased the production of reactive oxygen species (ROS), and the cell viability was partially restored by treatment with the ROS inhibitor N-acetyl-L-cysteine. In western blotting analysis, the expression of cdc2 was increased and LC3 was decreased by the simultaneous treatment of NAC and LCC. These results indicate that LCC may contribute to anti-tumor effects by inducing ROS-dependent G2/M arrest and autophagy in NSCLC. In conclusion, LCC treatment may be useful as a potential therapeutic agent against NSCLC.

Purification of Human HtrA1 Expressed in E. coli and Characterization of Its Serine Protease Activity (E. coli에서 발현된 human HtrA1 단백질의 정제와 HtrA1의 serine protease 활성 조건에 관한 연구)

  • Kim, Kyung-Hee;Kim, Sang-Soo;Kim, Goo-Young;Rhim, Hyang-Shuk
    • Journal of Life Science
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    • v.16 no.7 s.80
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    • pp.1133-1140
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    • 2006
  • Human HtrA1 (High temperature requirement protein A1) is a homologue of the E. coli periplasmic serine protease HtrA. A recent study has demonstrated that HtrA1 is a serine protease involved in processing of insulin like growth factor binding protein (ICFBP), indicating that it serves as an important regulator of IGF activity. Additionally, several lines of evidence suggest a striking correlation between proteolytic activity of HtrA1 serine protease and the pathogenesis of several diseases; however, physiological roles of HtrA1 remain to be elucidated. We used the pGEX bacterial expression system to develop a simple and rapid method for purifying HtrA1, and the recombinant HtrA1 protein was utilized to investigate the optimal conditions in executing its proteolytic activity. The proteolytically active HtrA1 was purified to approximately 85% purity, although the yield of the recombinant HtrA1 protein was slightly low $460{\mu}g$ for 1 liter E. coli culture). Using in vitro endoproteolytic cleavage assay, we identified that the HtrA1 serine protease activity was dependent on the enzyme concentration and the incubation time and that the best reaction temperature was $42^{\circ}C$ instead of $37^{\circ}C$. We arbitrary defined one unit of proteolytic activity of the HtrA1 serine protease as 200nM of HtrA1 that cleaves half of $5{\mu}M\;of\;{\beta}-casein$ during 3 hr incubation at $37^{\circ}C$. Our study provides a method for generating useful reagents to investigate the molecular mechanisms by which HtrA1 serine protease activity contributes in regulating its physiological function and to identify natural substrates of HtrA1.

Research libraries as a scholarly communication system (학술정보 커뮤니케이션 시스팀으로서의 연구도서관)

  • 이영자
    • Journal of Korean Library and Information Science Society
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    • v.9
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    • pp.179-211
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    • 1982
  • Many problems which today's research libraries are confronted with should be taken the measures to find some solutions in any ways. The purpose of this study is to identify the main stream of chaining of research libraries as an existing collector and distributor of scholarly information into a communication system adopting the concept of resource sharing and on-line bibliographic search as some possible ways for solutions. The conclusions of this study can be summarized as follows: 1) The research libraries will be imposed on more and more responsibilities to be a reservoir of the intellectual heritage of an individual, a nation and mankind. 2) The research libraries in the near future will have to develop their collections in the new environment of austerity with the limited budget. 3) It is more desirable for the future research libraries to have the attitude that they are in the business of information and communication rather than being an entity as "a library". 4) The resource sharing developed to solve the severe problems confrontal by research libraries will improve the organizational and technical mechanism for the access to the scholarly information. 5) The research libraries will produce more and more bibliographic database to expand the library materials which can be available and shared. 6) Though on-line search service will be sure to provide a considerable profit to the scholarly information users, it will take a long time for this service to be popularize because of the high ratio of service fee. 7) Two problems should be solved for the efficient service by on-line search. One is the continuous, updating training for the professional librarians. The other is that the common efforts for the quality control and standardization of data base by the data base producers should be made. 8) Taking all the items of the conclusions derived from the study of research libraries mainly in the United States into a consideration, the followings should be paid an attention. - The status-quo of the research libraries in Korea should be analyzed in very detailed and accurate way. - The problems of research libraries in Korea as the major scholarly communication system should be clarified based on the analysis. - The measures for the problems should be taken in the light of the unique characteristics of korean environment. - For the developing the most efficient measures, the formal organize action to lead and govern the long-aimed study on the problems of research libraries should be established and the government-level su n.0, pport for the legislation and finance should be provided for the realization of the result of the study.

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