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Membrane Protein Alterations Associated with Anticancer Drug Resistance in Mouse Lymphoblastic Leukemia L1210 Cells (항암제에 내성인 생쥐의 백혈병세포 L1210의 세포막 단백질의 변환)

  • Kim, Seong-Yong;Son, Sung-Kweon;Kim, Jae-Ryong;Kim, Jung-Hye
    • Journal of Yeungnam Medical Science
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    • v.10 no.2
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    • pp.432-444
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    • 1993
  • Multidrug resistance(MDR) phenotype is frequently observed in animal and human cancer cell lines selected for in vitro resistance to a single chemotherapeutic agent. It is characterized by the diminished drug accumulation and is related to the drug efflux mechanism in resistant cells. In the present study, adriamycin resistant cells(L1210-$AdR_6$ : $10^{-6}M$ adriamycin, $-AdR_5$ : $10^{-5}M$) and vincristine resistant cells (L1210-$VcR_7$ : $10^{-7}M$ vincristine, $-VcR_6$ : $10^{-6}M$) were produced from mouse lymphoblastic leukemia cell line L1210. Growth profiles of survived cells were observed for 5 days with MTT(thiazolyl blue) assay and resistance was compared with $IC_{50}$(drug concentration of 50% survival reduction in absorbance). Resistant cells proliferated more slowly than sensitive cell. Doubling times were 29.7hr in L1210, 68.7hr in L1210-$AdR_5$ and 58.2hr in $-VcR_6$. MDRs expressed as resistance factor were as follows, L1210-$AdR_5$ was 76.4 times for vincristine, L1210-$VcR_6$ was 96.4 times for adriamycin. The cell membrane proteins with three different M.W. were recognized to be related resistance, 220, 158, and 88 kd in L1210-$AdR_5$, 158, 140 and 88 kd in L1210-$VcR_6$ by SDS-PAG electrophoresis. Cell surface membrane proteins were identified by radio-iodination and autoradiogram, their molecular weights were 158, 72.8, and 42.4 Kd in L1210-$VcR_6$.

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The Effect of Local Irradiation in Prevention and Reversal of Acute Rejection of Transplanted Kidney with High-dose Steroid Pulse (국소적 방사선조사의 신장이식 후 거부반응에 대한 예방적 및 치료적 효과)

  • Kim I. H.;Ha S. W.;Park C. I.;Kim S. T.
    • Radiation Oncology Journal
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    • v.4 no.1
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    • pp.15-20
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    • 1986
  • From 1979 to 1984, 39 local allograft irradiations were given to 29 patients: 10 irradiations were administered for prevention and 29 for reversal of acute rejection of transplanted kidney. Three doses of 150 cGy every other day were combined with high-dose of methylprednisolone pulse (1 gm/day) for 3 days. For prevention of acute rejection, local irradiation was delivered on the days 1, 3, and 5 after the transplantation, and for reversal, irradiation started after the diagnosis of acute rejection. Eight out of 10 patients irradiated for prevention had acute allograft rejection, and, what is more, there was no surviving graft at 15 months after transplantation. Reversal of acute rejection was achieved in $71\%$. When the pre-irradiation level of serum creatinine was below $5.5mg\%$, the reversal rate was $93\%$, but above $5.5mg\%$ the reversal rate was only $17\%$ (p<0.01). Reirradiation after failure was not successful. Among 15 reversed patients, $7(47\%)$ had subsequent rejection (s). The functional graft survivals at 6 month, 1, 2, and 3 year were $70\%,\;65\%,\; 54\%,\;and\;54\%$, respectively. Therapeutic irradiation resulted in better graft survival when serum creatinine was below $5.5mg\%$ (p<0.001) or when irradiation started within 15 days after the diagnosis of acute rejection (p<0.001).

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Optimal Incentives for Customer Satisfaction in Multi-channel Setting (멀티채널에서의 고객만족제고 인센티브 연구)

  • Kim, Hyun-Sik
    • Journal of Distribution Research
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    • v.15 no.1
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    • pp.25-47
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    • 2010
  • CS is one of the major concerns of managers in the world because it is well known to be a key medium construct for firms' superior outcome. One of the major agents for CS management is retailers. Firms try to manage not only employees but also retailers to promote CS behaviors. And so diverse incentives are used to promote their CS behaviors under diverse channel setting such as multi-channel. However in spite of the rising needs there has been scarce studies on the optimal incentive structure for a manufacturer to offer competing retailers at the multi-channel. In this paper, we try to find better way for a manufacturer to promote the competing retailers' CS behaviors. We investigated how to promote the retailers' CS behavior via game-theoretic modeling. Especially, we focus on the possible incentive, CS bonus type reward introduced in the studies of Hauser, Simester, and Wernerfelt(1994) and Chu and Desai(1995). We build up a multi stage complete information game and derive a subgame perfect equilibrium using backward induction. Stages of the game are as following. (Stage 1) Manufacturer sets wholesale price(w) and CS bonus($\eta$). (Stage 2) Both retailers in competition set CS effort level($e_i$) and retail price($p_i$) simultaneously. (Stage 3) Consumers make purchasing decisions based on the manufacturer's initial reputation and retailers' CS efforts.

    Structure of the Model We investigated four issues about the topic as following: (1) How much total incentive is adequate for a firm of a specific level of reputation to promote retailers' CS behavior under multi-channel setting ?, (2) How much total incentive is adequate under diverse level of complimentary externalities between the retailers' CS efforts to promote retailers' CS behavior?, (3) How much total incentive is adequate under diverse level of cost to make CS efforts to promote retailers' CS behavior?, (4) How much total incentive is adequate under diverse level of competition between retailers to promote retailers' CS behavior? Our findings are as following. (1) The higher reputation has the manufacturer, the higher incentives for retailers at multi-channel are required in the equilibrium.
    shows the increasing pattern of optimal incentive level along the manufacturer's reputation level(a) under some parameter conditions(b=1/2;c=0;$\beta$=1/2). (2) The bigger complimentary externalities exists between the retailers' CS efforts, the higher incentives are required in the equilibrium.
    shows the increasing pattern of optimal incentive level along the complimentary externalities level($\beta$) under some parameter conditions(a=1;b=1/2;c=0). (3) The higher is the retailers' cost, the lower incentives are required in the equilibrium.
    shows the decreasing pattern of optimal incentive level along the cost level(c) under some parameter conditions(a=1;b=1/2;$\beta$=1/2). (4) The more competitive gets those two retailers, the higher incentives for retailers at multi-channel are required in the equilibrium.
    shows the increasing pattern of optimal incentive level along the competition level(b) under some parameter conditions(c=0;a=1;$\beta$=1/2). One of the major contribution points of this study is the fact that this study is the first to investigate the optimal CS incentive system under multi-channel setting.

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Effects of Feeding Dried Leftover Food on Productivity of Growing and Finishing Pigs (건조 남은음식물 급여가 육성돈과 비육돈의 생산성에 미치는 효과)

  • Cho, Y.M.;Kim, K.H.;Koh, H.B.;Chung, I.B.;Lee, G.W.;Bae, I.H.;Yang, C.J.
    • Journal of the Korea Organic Resources Recycling Association
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    • v.12 no.2
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    • pp.61-71
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    • 2004
  • These studies were conducted to investigate the effects of feeding dried leftover food (DLF) on growth, feed conversion and carcass characteristics of growing and finishing pigs. In experiment 1, seventy-five three-way cross-hybrids ($Yorkshire{\times}Landrace{\times}Duroc$) pigs weighing approximately 22 kg of body weight on average were assigned to five treatments in a completely randomized design. Each treatment had three replications with five pigs per replication. All pigs were fed experimental diets for 60 days. In experiment 2, seventy-five three-way cross-hybrids pigs weighing approximately 70 kg of body weight were fed experimental diets for 49 days. Each treatment had three replications with five pigs per replication. The treatments included 1) group offered control diet without DLF, 2) group offered diet containing DLF at 25%, 3) group offered diet containing DLF at 50%, 4) group offerred diet containing DLF at 25% with 10% higher protein level and 5) group offerred diet containing DLF at 50% and 20% higher protein level. Average daily gain of growing pigs was highest in control group among all the treatment groups except group offered diet containing DLF at 25% with no significant difference (P>0.05). Feed intake of DLF-offered groups were lower than that of control group while feed intake of groups fed diets containing DLF at 50% with 20% higher protein level was significantly higher (P<0.05) than that of control group. Feed conversion of growing pigs was not significantly different amont treatments although it seemed to be slightly improved in groups fed diets containing DLF at 25%. Average daily gain of finishing pigs fed diets containing DLF was significantly lower than that of control group. However there was no significant differences in average daily gain between groups fed diets containing DLF at 25% with 10% higher protein level and control group (P>0.05). Feed intakes were significantly decreased in DLF-fed groups compared to control group while there was no significant differences in feed intake between groups fed diets containing DLF with 10% and 20% higher protein levels and control group (P>0.05). Feed conversion was lowest in groups fed diets containing DLF at 25% with 10% higher protein level. However, there were no significant differences in feed conversion between groups fed diets containing DLF at 25% with 10% higher protein level and control group. Feed conversion of groups fed diets containing DLF at 50% was significantly higher than that of control group (P<0.05). Carcass weight was decreased with increasing levels of DLF in the diets. There were no significant differences in dressing percentage, backfat thickness and carcass grade among treatments. Feed cost per 1 kg body weight gain of finishing pigs was lowest in groups fed diets containing DLF at 25% with 10% higher protein level.

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Effect of Dietary Microbial Phytase on Laying Performance, Egg Quality, Phosphorus Utilization and Nutrient Metabolizability in Laying Hens (산란계에 Microbial Phytase 첨가시 산란율, 계란 품질, 인 이용율 및 영양소 대사율에 미치는 영향)

  • Jang, H.D.;Hyun, Y.;Kim, H.S.;Hwang, I.W.;Yoo, J.S.;Kim, H.J.;Shin, S.O.;Hwang, Y.;Zhou, T.X.;Chen, Y.J.;Cho, J.H.;Kim, I.H.
    • Korean Journal of Poultry Science
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    • v.35 no.2
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    • pp.115-121
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    • 2008
  • The study was conducted to evaluate the effects of dietary microbial phytase on egg productivity, egg quality, phosphorus utilization and nutrient digestibility in laying hens. The animals used in the experiment were a total of 120 Hy-Line Brown laying hens (32 weeks old). Dietary treatments included 1) CON (basal diet), 2) LP (low phosphorus diet) 3) NP (low phosphorus diet + 0.03% normal microbial phytase) and 4) CP (low phosphorus diet + 0.03% coated microbial phytase). Six laying hens were allotted to a block (pen) with five replicated. Through the whole period of experiment, egg production was significantly increased in CON and CP treatments compared to LP treatment (P<0.05). CON, CP and NP treatments significantly increased their egg shell breaking strength and egg shell thickness compared to LP treatment (P<0.05). CON, CP and NP treatments resulted higher yolk color and Haugh unit than LP treatment (P<0.05). Calcium and inorganic phosphorus contents in blood were higher in CP treatment compared to LP treatment (P<0.05). Dry matter digestibility and nitrogen digestibility were greater in CP treatment than CON, LP and NP treatments (P<0.05). Crude ash was increased in CON, CP and NP treatments compared to LP treatment (P<0.05). Calcium digestibility and phosphorus digestibility were significantly improved in CP and NP treatments than CON and LP treatments (P<0.05). Calcium retention of CON, CP and NP treatments were higher than LP treatment (P<0.05). Phosphorus retention was increased in CP and NP treatments compared to CON and LP treatments (P<0.05). LP treatment significantly increased their nitrogen, calcium excretion compared to CON, CP and NP treatments (P<0.05). Phosphorus excretion was decreased in LP, CP and NP treatments compared to CON treatment (P<0.05). In conclusion, CP treatment improved egg production, egg quality, inorganic calcium and phosphorus in blood, calcium and phosphorus retention and nutrient digestibility and decreased nitrogen and calcium excretion in laying hens.

Effect of Various β-1,3-glucan Supplements on the Performance, Blood Parameter, Small Intestinal Microflora and Immune Response in Laying Hens (β-Glucan 제제들이 산란계의 생산성, 혈액 성상과 소장내 미생물 균총 및 면역 체계에 미치는 영향)

  • Park, K.W.;Rhee, A.R.;Lee, I.Y.;Kim, M.K.;Paik, I.K.
    • Korean Journal of Poultry Science
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    • v.35 no.2
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    • pp.183-190
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    • 2008
  • This study was conducted to investigate the effect of feeding diets supplemented with ${\beta}-glucan$ products on the performance, small intestinal microflora and immune response in laying hens. The ${\beta}-glucan$ products used in the experiment were $BetaPolo^{(R)}$ ; soluble ${\beta}-glucan$ of microbial cell wall origin, $HiGlu^{(R)}$ ; microbial cell wall origin, $OGlu^{(R)}$ ; oat origin, $BGlu^{(R)}$ ; barley origin. A total of 720 Hy-Line Brown laying hens of 40wks old were divided into 5 dietary treatments : T1 ; Control( C), T2 ; $BetaPolo^{(R)}$, T3 ; $HiGlu^{(R)}$, T4 ; $OGlu^{(R)}$, T5 ; $BGlu^{(R)}$. Each treatment was replicated 4 times with 36 birds/replicate housed in 2 bird cages, and arranged according to completely randomized block design. Feeding trial lasted 40ds under 16 h lighting regimens. There were significant differences among treatments in hen-house egg production feed intake and feed conversion. HiGlu treatment was significantly higher than OGlu treatments in hen-house egg production. ${\beta}-glucan$ supplemented treatments were lower than the control in feed intake and feed conversion ratio. All ${\beta}-glucan$ supplemented treatments were significantly higher than the control in eggshell strength. Eggshell color and Haugh unit tended to be lower in the supplemented group than the control. IgY concentration was not significantly affected by treatments. At $5^{th}$ week of experiment, however, IgY concentration tended to increase in the supplemented groups. Among the leucocytes parameters, WBC, heterophil, lymphocytes, monocyte and eosinophil concentration were lower in the supplemented groups than those of the control. Among erythrocytes, HCT(hematocrit) and MCV(mean corpuscular volume) were significantly affected by treatment. MCV of supplemented groups were higher than that of the control. Immunoglobulin concentrations in the birds were not significantly different among treatments. However, IgA concentration tended to be low in the supplemented groups than the control. The cfu of small intestinal microflora were not significantly different among treatments, but that of Cl. perfringens tended to be lower than the control. The result of this experiment indicateted that feeding ${\beta}-glucan$ to laying hens improve feed conversion ratio and eggshell strength. Also intestinal microflora and immune responses are modified.

Results of Coventional Radiotherapy for Carcinomas of the Tonsillar Region (편도암의 방사선 치료 성적)

  • Nah Byung Sik;Nam Taek Keun;Ahn Sung Ja;Chung Woong Ki
    • Radiation Oncology Journal
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    • v.15 no.2
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    • pp.97-104
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    • 1997
  • of $PLC-\gamma$ 1 activity. Results : In the immunohistochemistry, the expression of $PLC-\beta$ was negative for all grnups. The expression of $PLC-\gamma$ 1 was highest in the group III followed by group II in the proliferative zone of mucosa. The expression of PKC-01 was strong1y positive in group I followed by group II in the damaged surface epithelium. The above findings were also confirmed in the immunoblotting study. In the irnrnunoblotting study, the expressions of $PLC-\beta,\;PLC-\gamma\;1,\;and\;PLC-\delta$ were the same as the results of immunohistochemistry The expression of ras oncoprotein was weakly Positive in groups II, III and IV. The of EGFR was the highest in the group II, III, followed by group W and the expression of PKC was weakly positive in the group II and III. Conclusion : $PLC-\gamma$ 1 mediated signal transduction including ras oncoprotein, EGFR, and PKC play a significant role irL mucosal regeneration after irradiation. $PLC-\delta$ 1 mediated signal transduction might have an important role in mucosal damage after irradiation. Further studies will be necessary to confirm the signal transduction mediating the $PLC-\delta$ 1.

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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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Biogas Production from Anaerobic Co-digestion Using the Swine Manure and Organic Byproduct (돈분과 유기성 부산물을 혼합한 혐기소화에서 바이오가스 생산)

  • Kim, W.G.;Oh, I.H.;Yang, S.Y.;Lee, K.M.;Lee, S.I.
    • Journal of Animal Environmental Science
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    • v.17 no.1
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    • pp.49-54
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    • 2011
  • Animal manure is produced annually 43.7 million tonnes in Korea. Among them, about 85.6 % are used as compost or liquid fertilizer to the agricultural land. The animal manure can be effectively utilized by mixing with organic byproducts that result in generation of biogas from anaerobic co-digestion process. This study aimed to optimize the content of total solid materials (TS) and determine the effect of organic byproduct on the co-digestion process. Prior to the byproduct treatments, determination of proper content of TS was conducted by controlling at 5 or 10 %. For the byproduct treatments, swine manure without adding the byproduct was used for control treatment, and swine manure mixed with either corn silage or kitchen waste was used for other treatments. Volume of biomethane ($CH_4$) generated from digested materials was quantified before and after byproduct treatments. In result, a 1.4-fold higher biomethane, about 0.556 L/$L{\cdot}d$, was produced when the content of TS was controlled at 10 %, compared at 5 %, about 0.389 L/$L{\cdot}d$. When the swine manure was mixed with the corn silage or kitchen waste, a two-fold higher biomethane was produced, about 1.theand 1.0heL/$L{\cdot}d$, respectively, compared to the control treatment. Biogas production from organic dry matter (odm) was a3, 362eand 2h6 L/kg odm${\cdot}$d for control, corn silage, and kitchen waste treatment, respectively. The lower biogas production in the treatment of kitchen waste than that of corn silage is associated with its relatively high odm contents. The methane concentration during the whole process ranged from 40 at the beginning to 70 % at the end of process for both the control and kitchen waste treatments, and ranged from 52 to 70 % for the corn silage treatment. Hydrogen sulfide ($H_2S$) concentration ranged between 350 and 500 ppm. All the integrated results indicate that addition of organic byproduct into animal manure can double the generation of biogas from anaerobic fermentation process.

Population density of potato virus vectors In the Kwanghwal Area, Kimje-gun, Cholla-Pukto, on the western coast (씨감자 생산을 위한 매개 진딧물 조사 - 전북 김제군 광활면의 진딧물 분포상 -)

  • Paik Woon Hah
    • Korean journal of applied entomology
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    • v.7
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    • pp.5-13
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    • 1969
  • Present system of seed potato production in Korea has several weak points and consequently has difficulties in covering annual shortage of 60,000 tons of seed potatoes. The author has an opinion that this so called 'High land system' of seed potato production adopted by the Government should be replaced by the 'Coastal area system' which is proposed by the author and has many advantages over present 'High land system'(2). In coastal areas where enormous acreage of rice paddies are spread, mostly around the villages. the primary host plants of the vectors are found. Therefore, the only source of aphid vectors are limited to the villages. The farmer's houses scattered more sparsely also have minor importance. In the previous paper(2), the author reported that the aphid vector populations were lower in the coastalareas than at Taegwanryong where the Alpine Experiment Station for the production. of seed potatoes is located. However, the number to vectors at Okku showed rather high density, where the trap was placed at the distance of 200 m from a village where peach and Hibiscus trees, the primary hosts of Myzus pesrsicae and Aphis gossypii were grown. To clarify the flight distance from the source of the aphid vectors, a trial was carried out in the Kwanghwal area, Kimje-gun, Cholla-pukto. on the western coast. 13 traps were placed at four directions and the distances between the traps were 250 m. (Fig. I) The traps 'Were operated from June 21 to October 31. The results are shown in Table 1. A total of some 70 species of aphids were found, including 5 speceis of potato virus vectors. The vectors are as follows: I. Myzus persicae (Sulzer) 2. Aphis gossypii Glover 3. Aulacorthum solani (Kaltenbach) 4. Lipaphis erysimi (Kaltenbach) 5. Macrosiphoniella sanborni (Gillette) Out of a total of 12,797 aphids, 5,187$(48\%)$ vectors were found. The trap catches at the 13 locations are shown in Fig. 2 and the numbers of the vectors at each location for each vector, except Macro-siphoniella sanborni. of which only a single individual was caught, are shown in Fig. 3-6. Number of vectors at C (3,279) (Centre of the village) is considerably higher than that at Suwon (763); however, EI. SI. WI and NI. where the distanecs from Care 250 m, showed lower numbers of vectors than that at Taegwanryong (347). The number of vectors at NI was rather than at the other 3 locations at the distance of 250m from the village. This was because C was in the southern part of the village. Consequently NI was much closer to the village than the other 3 locations of the same distance from C. Numbers of catches of the most important vector. Myzus persicae, are shown in Fig.3. The distribution pattern is typical except $S-2\;and\;W_3$, where several farmer's houses were found. If only the rice paddies were found in these locations. the numbers of the vectors would be small as the distances increase. Numbers of catches of the other 3 vectors are shown in Fig. 4-6. From these results. the author has drawn the following conclusions: 1. The aphid vector sources at the rice paddy belt in the western coast are the villages. 2. The vector densities at the locations where the distances are 250 m from the centre of the village are lower than that at Taegwanryong. 3. The vector densities become gradually lower as the distances from the centre of village increase. However. depending on the host plant situation at each location, the vector densities are variable. These minor sources of aphid vectors may be eliminated so that seed potatoes can be grown. 4. Thus. under the direction of specialists, fields suitable for seed potato production can be found in the coastal areas.

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