• Title/Summary/Keyword: Type Synthesis

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Adhesion-induced generation of oxygen free radical from human alveolar macrophages and its mechanisms (폐포대식세포의 부착에 의한 산소유리기 분비능 활성화 및 그 기전)

  • Chung, Man-Pyo;Yoo, Chul-Gyu;Kim, Young-Whan;Han, Sung-Koo;Shim, Young-Soo;Han, Yong-Chol
    • Tuberculosis and Respiratory Diseases
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    • v.43 no.2
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    • pp.210-220
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    • 1996
  • Background : Neutrophils or monocytes separated in vitro by the adherence to plastic surface are known to be activated by surface adherence itself and subsequent experimental data might be altered by surface adherence. In the process of surface adherence, adhesion molecules have a clear role in intracellular signal pathway of cellular activation. Human alveolar macrophages(HAM) are frequently purified by the adherence procedure after bronchoalveolar lavage. But the experimental data of many reports about alveolar macrophages have ignored the possibility of adhesion-induced cellular activation. Method : Bronchoalveolar lavage was performed in the person whose lung of either side was confirmed to be normal by chest CT. With the measurement of hydrogen peroxide release from adherent HAM to plastic surface and non-adherent HAM with or without additional stimulation of phorbol myristate acetate(PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP), we observed the effect of the adherence to plastic surface. We also evaluated the effect of various biological surfaces on adhesion-induced activation of HAM. Then, to define the intracellular pathway of signal transduction, pretreatment with cycloheximide, pertussis toxin and anti-CD11/CD18 monoclonal antibody was done and we measured hydrogen peroxide in the culture supernatant of HAM. Results : 1) The adherence itself to plastic surface directly stimulated hydrogen peroxide release from human alveolar macrophages and chemical stimuli such as phorbol myristate acetate(PMA) or N-formyl-methionyl-leucyl-phenylalanine(fMLP) colud not increase hydrogen peroxide release in these adherent macrophages which is already activated. 2) PMA activated human alveolar macrophages irrespective of the state of adhesion. However, fMLP stimulated the release of hydrogen peroxide from the adherent macrophages, but not from the non-adherent macrophages. 3) HAM adherent to A549 cell(type II alveolar epithelium-like human cell line) monolayer released more hydrogen peroxide in response to both PMA and fMLP. This adherence-dependent effect of fMLP was blocked by pretreatment of macrophages with cycloheximide, pertussis toxin and anti-CD18 monoclonal antibody, Conclusion : These results suggest that the stimulatory effect of PMA and fMLP can not be found in adherent macrophage because of the activation of human alveolar macrophage by the adherence to plastic surface and the cells adhered to biologic surface such as alveolar epithelial cells are appropriately responsive to these stimuli. It is also likely that the effect of fMLP on the adherent macrophage requires new protein synthesis via G protein pathway and is dependent on the adhesion between alveolar macrophages and alveolar epithelial cells by virtue of CD11/CD18 adhesion molecules.

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Potential Antitumor $\alpha$-Methylene-$\gamma$-butyrolactone-Bearing Nucleic Acid Base. 3. Synthesis of $5^1$-Methyl-$5^1$-[(6-substituted-9H-purin-9-yl)methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofurans

  • Kim, Jack-C.;Kim, Si-Hwan;Kim, Ji-A;Choi, Soon-Kyu;Park, Won-Woo
    • Archives of Pharmacal Research
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    • v.21 no.4
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    • pp.458-464
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    • 1998
  • Search for a new $\alpha$-methylene-$\gamma$-butyrolactone-bearing 6-substituted purine as a potental antitumor agent has led to synthesize seven, hitherto unreported, $5^1$-Methyl-$5^1$-[(6-substituted-9H-purin-9-yl)methyl]-$2^1$-oxo-$3^1$- methylenetetrahydrofurans (H, Cl, l, $CH_3$, $NH_2$, SH, >C=O) (6a-g). These include $5^1$-Methyl-$5^1$-[(9H-purin-9-yl)methyll-$2^1$-oxo-$3^1$ -methylenetetrahydrofurans (6a), $5^1$-Methyl-$5^1$-[(6-chloro-9H-purin-9-yl)methyl]-$2^1$-oxo-$3^1$-methylenetetrahydr ofurans (6b), $5^1$-Methyl-$5^1$-[(6-chloro-9H-purin-9-yl) methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofurans (6c), $5^1$-Methyl-$5^1$-[(6-methyl-9H-purin-9-yl) methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofurans (6d), $5^1$-Methyl-$5^1$-[(9H-adenin-9-yl)methyll-$2^1$-oxo-$3^1$-methylenetetrahydrofurans (6e), $5^1$-Methyl-$5^1$-[(6-mercapto-9H-purin-9-yl) methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofurans (6f) and $5^1$-Methyl-$5^1$-[(9H-hypoxanthin-9-yl)methyll-$2^1$-oxo-$3^1$-methylenetetrahydrof urans (6g) which were made by the Reformatsky-type reaction of ethyl $\alpha$-(bromomethyl) acrylate with the corresponding (6-substituted-9H-purin-9-yl)-2-propanone intermediates (5a-g). These ketone intermediates 5a-g, 1-(9H-purin-9-yl)-2-propanone (5a), 1-(6-chloro-9H-purin-9-yl)-2-propanone (5b), 1-(6-iodo-9H-purin-9-yi)-2-propanone (5c), 1-(6-methyl-9H-purin-9-yl)-2-propanone (5d), 1-(9H-adenin-9-yl)-2-propanone (Se), 1-(6-mercapto-9H-purin-9-yl)-2-propanone (5f), and 1-(9H-hypoxanthin-9-yl)-2-propanone (5g) were directly obtained by the alkylation of the 6-substituted purine bases with the chloroacetone in the presence of $K_2$$CO_3$ (or NaH) under DMF (or DMSO). The preliminary in vitro cytotoxcity assay for the synthetic .alpha.-methylene-y-butyro-lactone compounds (6a-g) were determined against three cell lines (PM-3A, P-388, and K-562) and showed the moderate antitumor activity ($IC_50$ ranged from 1.4 to 4.3 $\mu\textrm{g}$/ml) with the compound $5^1$-methyl-$5^1$ -[(9H-hypoxanthin-9-yl)methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofuran (6g) showing the least antitumor activity.

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Prevention of thromboembolism with ticlopidine and aspirin after cardiac valve replacement (심장변막치환후 Ticlopidine과 Aspirin의 혈전방지 효과)

  • Kim, Gwang-Taek;Kim, Hak-Je;Kim, Hyeong-Muk
    • Journal of Chest Surgery
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    • v.19 no.1
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    • pp.35-42
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    • 1986
  • Prevention of thrombombolism after rosthetic cardiac valve replacement is essential for the patients. About 90% of patients are free of major and minor thromboembolic complications 5 year after replacement of cardiac valves with prosthetic devices when they are under control of anticoagulant therapy. Ticlopidine is a drug that alter platelet function to have an antithrombotic effect. It is an antiaggregating agent which inhibits primary platelet function to have an antithrombotic effect. It is an antiaggregating agent which inhibits primary platelet aggregation induced by ADP and increases the production of prostaglandin $D_{2}$. Aspirin in small doses inhibits platelet synthesis of prostaglandins by irreversibly blocking the enzyme cyclo-oxygenase. Platelet secretion and aggregation are impaired with Ticlopidine and Aspirin. the thromboembolic event sof 54 patient s who were treated with Ticlopidine and Aspirin after cardiac valve replacement were evaluated and compared with that of 79 patients who were treated with Wafarin and Aspirin after the same type of operation. The follow-up period ranged from 4 to 110 months (mean of 48 months). there were 11 major thromboembolic episodes including three deaths in the warfarin goup during mean follow-up period of 56 months. two cases of CVA and one hemoarthrosis were noted due to overdose of Warfarin. Inticlopidine group, there was only one fatal thromboembolic epdisode three month after mitral valve replacement during mean follow-up period of 18 months. Two episodes of hypermenorrhea resulting anemia ere noted in the ticlopidine group. We measured the parameters of platelet function in aggreagation curve of platelet with platelet aggregometer (chrono-log Aggregometer, Model No. 430) Aggregation test was performed with three final concentrations of epinephrine in 10 uM/L, ADP in 5uM/L. 28 patients with prosthetic cardiac valves and 35 healthy volunteers were subgrouped as follows to analyze the effect of antithrombotic drugs used. Group I ; 11 patients treated with 250-500 mg of ticlopidine and 0.5gm of Aspirin as a daily single dose after cardiac valve replacement (14 St. Jude Medical and 1 Carpentier-Edwards, 9 patients with atrial fibrillation among them) Group II ; 10 patients treated with 3-5 mg of Warfarin and 0.75 gm of Aspirin daily to prolong prothrombin time around 20 seconds for more than 6 months and single Aspirin dose was maintained afterward as a life-long regimes(3 St. Jude Medical, 1 Hall-Kaster and 7 Carpentier-Edwards valve, 9 patients in atrial fibrilation). Group III ; 7 patients who quit anticoagulant treatment (Warfarin + Aspirin) 6-12 months after the regime as group II (3 St. Jude Medical. 1 bjork-Shiley, 1 Hall-Kaster, 3 Carpentier-Edwards valve, 2 of them are with atrial fibrillation). Group IV ; 35 healthy vounteers (28 males and 7 females). The following results were obtained. 1. The mean maximal platelet aggregability in Group I induced by 10uM/L epinephrine was 15.6%, and 17.5 and 18.7% in BM in proportion to the induction by 5 and 10 uM/L ADP. 2. The mean maximal platelet aggregability in Group II induced by 10uM/L epinephrine was 16.5%, and 27.4 and 44.7% in BM in proportion to the induction by 5 and 10uM/L ADP. 3. The mean maximal platelet aggregability in group III induced by 10uM/L epinephrine was 65%, and 56.5 and 51.8% in BM in proportion to the induction by 5 and 10 uM/L ADP. 4. The mean maximal platelet aggregability in the normal subjects induced by 10 uM/L epinephrine was 64%, and 65 and 69% in Bm inproportion to the induction by 5 and 10 uM/L ADP. 5. Reversible change of platelet aggregation curve induced by 5 and 10uM/L was noted all of the patients in Group I. conclusion : Ticlopidine is an antiaggregating agent which inhibits primary platelet aggregation induced by ADP, and increases the production of prostaglandin $D_{2}$. Ticlopidine and Aspirin produced a significant inhibition of platelet in the presence of ADP and epinephrine in our study. Acccording to our brief experience, 250 mg of ticlopidine and low dose of Aspirin resulted synergistic superior effect to each drug alone in prevention of thromboembolism after prosthetic cardiac valve replacement.

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A quantitative study on the minimal pair of Korean phonemes: Focused on syllable-initial consonants (한국어 음소 최소대립쌍의 계량언어학적 연구: 초성 자음을 중심으로)

  • Jung, Jieun
    • Phonetics and Speech Sciences
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    • v.11 no.1
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    • pp.29-40
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    • 2019
  • The paper investigates the minimal pair of Korean phonemes quantitatively. To achieve this goal, I calculated the number of consonant minimal pairs in the syllable-initial position as both raw counts and relative counts, and analyzed the part of speech relations of the two words in the minimal pair. "Urimalsaem" was chosen as the object of this study because it was judged that the minimal pair analysis should be done through a dictionary and it is the largest among Korean dictionaries. The results of the study are summarized as follows. First, there were 153 types of minimal pairs out of 337,135 examples. The ranking of phoneme pairs from highest to lowest was 'ㅅ-ㅈ, ㄱ-ㅅ, ㄱ-ㅈ, ㄱ-ㅂ, ㄱ-ㅎ, ${\ldots}$, ㅆ-ㅋ, ㄸ-ㅋ, ㅉ-ㅋ, ㄹ-ㅃ, ㅃ-ㅋ'. The phonemes that played a major role in the formation of the minimal pair were /ㄱ, ㅅ, ㅈ, ㅂ, ㅊ/, in that order, which showed a high proportion of palatals. The correlation between the raw count of minimal pairs and the relative count of minimal pairs was found to be quite high r=0.937. Second, 87.91% of the minimal pairs shared the part of speech (same syntactic category). The most frequently observed type has been 'noun-noun' pair (70.25%), and 'vowel-vowel' pair (14.77%) was the next ranking. It can be indicated that the minimal pair could be grouped into similar categories in terms of semantics. The results of this study can be useful for various research in Korean linguistics, speech-language pathology, language education, language acquisition, speech synthesis, and artificial intelligence-machine learning as basic data related to Korean phonemes.

New Functional Properties of Passion Fruit Extract on Skin (패션 프룻 추출물이 피부에 미치는 새로운 기능적 효과)

  • Jeong, Mi Suk;Kim, Soon-Rae;Han, Chang Woo;Kim, Hyeon Jin;Jang, Se Bok
    • Journal of Life Science
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    • v.32 no.2
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    • pp.101-107
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    • 2022
  • In this research, the anti-inflammatory, antioxidant, antiaging, and skin whitening properties of pulp and seed extracts of passion fruit were studied. The result of the primary skin irritation test using a skin-attached patch determined the skin irritation index to be 0.00 for the passion fruit extract. In addition, RAW 264.7 macrophages produce NO by stimulation of lipopolysaccharides, and the application of extracts to this resulted in significantly lower NOs, confirming the excellent anti-inflammatory properties of passion fruit extracts. The 2,2-diphenyl-1-picrylhydrazyl test further confirmed that the passion fruit extract exhibits a good 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate radical scavenging ability of 5.11% and strong antioxidant properties. The presence of collagen type I in the skin is a measure of aging and various skin diseases. The results obtained from the analysis of the activity of human procollagen I alpha 1 confirmed that the passion fruit extract reduces the synthesis of procollagen. In addition, the skin whitening property of the passion fruit extract was confirmed by the melanin inhibition test, and a sample was obtained that contained more than 2% of arbutin, a whitening agent approved by the Ministry of Food and Drug Safety, which is generally present in the form of a white powder and is used as a functional ingredient. This confirms that the whitening efficacy of the passion fruit extract obtained from nature contributes to the development of functional raw materials for cosmetics and food.

Effects of polygalacin D extracted from Platycodon grandiflorum on myoblast differentiation and muscle atrophy (길경에서 추출한 polygalacin D가 근원세포 분화 및 근위축에 미치는 영향)

  • Eun-Ju Song;Ji-Won Heo;Jee Hee Jang;Eonmi Kim;Yun Hee Jeong;Min Jung Kim;Sung-Eun Kim
    • Journal of Nutrition and Health
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    • v.56 no.6
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    • pp.602-614
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    • 2023
  • Purpose: The balance between synthesis and degradation of proteins plays a critical role in the maintenance of skeletal muscle mass. Mitochondrial dysfunction has been closely associated with skeletal muscle atrophy caused by aging, cancer, and chemotherapy. Polygalacin D is a saponin derivative isolated from Platycodon grandiflorum (Jacq.) A. DC. This study aimed to investigate the effects of polygalacin D on myoblast differentiation and muscle atrophy in association with mitochondrial function in in vitro and in zebrafish models in vivo. Methods: C2C12 myoblasts were cultured in differentiation media containing different concentrations of polygalacin D, followed by the immunostaining of the myotubes with myosin heavy chain (MHC). The mRNA expression of markers related to myogenesis, muscle atrophy, and mitochondrial function was determined by real-time quantitative reverse transcription polymerase chain reaction. Wild type AB* zebrafish (Danio rerio) embryos were treated with 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) with or without polygalacin D, and immunostained to detect slow and fast types of muscle fibers. The Tg(Xla.Eef1a1:mitoEGFP) zebrafish expressing mitochondria-targeted green fluorescent protein was used to monitor mitochondrial morphology. Results: The exposure of C2C12 myotubes to 0.1 ng/mL of polygalacin D increased the formation of MHC-positive multinucleated myotubes (≥ 8 nuclei) compared with the control. Polygalacin D significantly increased the expression of MHC isoforms (Myh1, Myh2, Myh4, and Myh7) involved in myoblast differentiation while it decreased the expression of atrophic markers including muscle RING-finger protein-1 (MuRF1), mothers against decapentaplegic homolog (Smad)2, and Smad3. In addition, polygalacin D promoted peroxisome proliferator-activated receptor-gamma coactivator (Pgc1α) expression and reduced the level of mitochondrial fission regulators such as dynamin-1-like protein (Drp1) and mitochondrial fission 1 (Fis1). In a zebrafish model of FOLFIRI-induced muscle atrophy, polygalacin D improved not only mitochondrial dysfunction but also slow and fast muscle fiber atrophy. Conclusion: These results demonstrated that polygalacin D promotes myogenesis and alleviates chemotherapy-induced muscle atrophy by improving mitochondrial function. Thus, polygalacin D could be useful as nutrition support to prevent and ameliorate muscle wasting and weakness.

Transferrin Receptors in the Liver Cell Membrane of Carcinogen (3-methyl-4-dimethyl-arninoazobenzene) Treated Rat (Carcinogen (3-methyl-4-dimethyl-aminoazo benzene) 처리후 간세포막에서의 Transferrin Receptor 변동에 관한 연구)

  • Lee, Jae-Heun;Ro, Eu-Sun;Hur, Gang-Min;Lee, Choong-Sik;Seok, Jeong-Ho
    • The Korean Journal of Pharmacology
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    • v.29 no.1
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    • pp.85-96
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    • 1993
  • To investigate the alteration of transferrin receptor (TfR) in the proliferating or transformed liver cells, $^{125}I-transferrin$ binding experiment was carried out in the isolated parenchymal cells (PC) or nonparenchymal cells (NPC) from normal regenerated rat liver after partial hepatectomy and from the liver of 3-methyl-4-dimethyl-aminoazobenzene (3-Me-DAB) treated rat. With the administration of 3-Me-DAB for 8 weeks, the liver tissue showed marked morphologic changes of oval cell proliferation, regenerations of hepatocytes, and atypical proliferations of bile ducts, but these changes were little affected by partial hepatectomy. Transferrin binding values in PC or NPC homogenate from the regenerated liver of normal rat, were increased by 3rd day and diminished to control level at 7th day after partial hepatectomy. With the treatement of 3-Me-DAB for 8 weeks, transferrin binding sites in homogenates were higher than those of normal rat liver and increased by 7th day after partial hepatectomy. Transferrin binding sites (Bmax) in the cell membrane of NPC were higher than those of PC of normal rat liver, but there was no significant difference in Kd values between both groups (5.05, 6.3 nM). In the normal resenerated rat liver, transferrin binding sites in the PC or NPC plasma membrane, were increased by 3rd day and diminished to control level at 7th day after partial hepatectomy. With 3-Me-DAB tratment, transferrin binding sites in both liver NPC and PC plasma membrane were increased about 3 folds, compared to those in each plasma membrane of normal rat liver. And after partial hepatectomy of 3-Me-DAB trated rat, transferrin binding sites were increased by the 3rd day in the NPC plasma membrane but increased by the 7th day in the PC plasma membrane. In the transferrin binding sites of the PC or NPC plasma membrane of 3-Me-DAB treated liver, two kinds of Kd values $(3.1{\sim}4.7\;nM,\;25.4{\sim}54.1\;nM)$ were detected. The present results suggest that 1) TfRs are distributed in the liver PC as well as NPC; 2) Increased TfRs in PC or NPC plasma membrane of normal regenerated liver after partial hepatectomy and 3-Me-DAB treated rat liver, may be due to increased intracellular synthesis; 3) Increased TfRs in normal regenerated liver after partial hepatectomy might be related to the expression of a single type of high affinity site $(Kd,\;3.1{\sim}7.5\;nM)$, but in 3-Me-DAB treated rat liver might be related to the expression of high and low affinity types of receptors $(Kd,\;25.4{\sim}54.1\;nm)$.

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Agronomical studies on the major environmental factors of rice culture in Korea (수도재배의 주요환경요인에 관한 해석적 조사연구)

  • Yung-Sup Kim
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.3
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    • pp.49-82
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    • 1965
  • For the stable and high yields of low-land rice in Korea, the characteristics of rice plant for the vegetative and physiological responses, plant type formation, and yield components have been studied in order to obtain the fundamental data for the improvement of cultural practices, especially for the ideal fertilizer application. Furthermore the environmental conditions in Korea including temperatures, light, precipitation, and soil conditions have been compared in the broad sense with those in Japan, and the application of nitrogen, phosphorus, potassium, silicate and other micro-nutrients were described in relation to the characteristics of environmental conditions for the improvement of fertilizer application. 1. The average yield of polished-rice per 10 are in Korea is about 204 kg and this values are much less than those in Japan and Taiwan where they produce 77% to 13% more than in Korea. The rate of yield increase a year in Korea is 4.2 kg, but in Japan and Taiwan the rates of yield increase a year are 81 % and 62%, respectively. It was also found that the coefficient of variation of yield is 7.7% in Korea, 6.7% in Japan and 2.5% in Taiwan. This means that the stability of producing rice in Korea is very low when compared with those in Japan and Taiwan. 2. It was learned from the results obtained from the 'annual yield estimation experiment' that there are big differences in the respect of plant type formations between rice crops grown in Japan and Korea. The important differences found were as follows: (1) The numbers of spikelets per 3.3 square meters are 891 in Korea and 1, 007 in Japan(13% more than in Korea). (2) The numbers of tillers per 3.3 square meters at the stage of maximum tillering are 1, 150 in Korea, but in Japan they showed 19% more than in Korea. (3) The ratio of effective tillers to total tillers is 77.5% in Korea and 74.7% in Japan, which seems to be higher in Korea than in Japan. But the ratio in Korea is very low when considered the numbers of total tillers in both countries. (4) The ratio of grain to straw is 85.4% in Korea and 96.3% in Japan. 3. The average temperatures during the growing season at the area of Suwon, Kwangjoo and Taegu are almost same as those in the district of Jookokoo(Fookoo yama) in Japan, i.e., the temperatures during the rice-growing season in Korea are similar to those in the southern-warm regions of Japan. 4. Considering the minimum temperatures at the stage of limiting transplanting, 13$^{\circ}C$, the time of transplanting might be 30 to 40 days earlier than presently practicing transplanting time, which comes around June 10. 5. The temperatures during the vegetative growth in Korea were higher than those temperatures that needed in the protein synthesis which ate the main metabolism during this stage. However, the temperatures at the time of reproductive growth was lower than the temperatures that needed in the sugar assimilation which is main metabolism in this stage. In this point of view, it might be considered that the proper time of growing rice plant in Korea would be rather earlier. 6. The temperatures and the day light conditions at the time of first tillering stage of rice plant, when planted as presenting transplanting practices, are very satisfactory, but the poor day light length, high temperatures and too wet conditions in the time of last-tillering stage(mid or last July) might cause the occurrence of disease such as blast. 7. The heading stage of rice plants at each region through nations when planted as presently practicing method comes when the day light length is short. 8. It was shown that the accumulated average air-temperature at the time of maturing stage was not enough and the heading time was too late, when considered the annual deviations of mean temperatures and low minimum temperatures. 9. The nitrogen content of each plant part at the each growing stage was very high at the stage of vegetative growth when compared with the nitrogen content at the stage of reproductive growth after heading. In this respect it was believed to be important to prevent the nutrient shortages at the reproductive stages, especially after the heading. 10. The area of unsatisfactory irrigation paddy fields and natural rain-fed paddy fields are getting reduced in Korea. The correlation between the rate of reducing unsatisfactory irrigation and natural rain-fed paddy fields and the rate of yield increase were computed. The correlation coefficients(r) between the area of unsatisfactory irrigation paddy fields and yield increase were +0.525, and between the natural rain-fed paddy fields and yield increase, +0.832 and between the unsatisfactory irrigation plus natural rain-fed paddy fields and yield increase, +0.84. And there were. highly significant positive correlations between natural rain-fed paddy fields and yield increases indicating that the less the area of natural rain-fed paddy fields, the greater the yields per unit area. 11. The results obtained from the fertilizer experiments (yield performance trials) conducted in both Korea and Japan showed that the yield of non-fertilized plots per 10 are was 231 kg in Korea and 360 kg in Japan. On the basis of this it might be concluded that the fertility of soil in Korea is lower than that in Japan. Furthermore it was. also found that the yields of non-nitrogen applied plots per 10 are were 236 kg in Korea and 383 kg in Japan. This also indicates that the yields of rice in Korea are largely depending on the nitrogen content in the soil. 12. The followings were obtained when the chemical natures of soils in both Korea and Japan were compared. (1) The content of organic matter, total nitrogen, exchangeable calcium, and magnesium in Korea were no more than the half those in Japan. (2) The content of N/2 chloride and soluble silicate in low-land soil were on the average lower in Korea. (3) The exchange capacity of bases in Korea was no more than half that in Japan. 13. It was also observed by comparing the soil nature of the soil with high yielding capacity with the soil with low yielding capacity that the exchange capacity of bases, exchangeable calcium and magnesium, potassium, phosphorus, manganese, silicate and iron were low in the soil with low yielding capacity. 14. The depth of furrow slice was always deeper in the soil with high yielding capacity, and the depth of furrow slice in Korea was also shallower than that in Japan. 15. Summarizing the various conditions mentioned previously and considering the effects of silicate and trace elements such as manganese and iron besides three elements on the physiological and plant type formation of rice crops, more realistic and more ideal fertilizing practices were proposed. proposed.

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