• Title/Summary/Keyword: Constant potential

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Electrical Feeding Patterns and Stylet Movement of Rice Brown Planthopper, Nilaparvata lugens(Homoptera), in the Rice Tissues (벼멸구의 섭식 패턴과 벼 조직내에서 구침의 이동)

  • 윤영남;장영덕
    • Korean journal of applied entomology
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    • v.32 no.2
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    • pp.208-217
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    • 1993
  • Feeding behavior fo female brown planthoppers, Nilaparvata lugens Stal, was examined with an electrical recording technique using DC amplifier and through anatomical observation of stylet ovement in the rice plat with electrical recordings. There was six feeding patterns, type P, S, SB, O, X and Ph with the brown planthopper. Type P was a probing pattern during searching the proper feeding site. Type S appeared to be associated with the initial penetration and changing direction through the tissues, and from this type type SB pattern could be distinguished by the regularity of the large potential drops seen, and might be associated with penetration of the phloem sheath and/or salivation in the phloem sheath. The type O pattern shows none of the large voltage drops which were believed to occur when cell walls were being broken down and passes through a relatively thin layer of cells into an air space. The very constant waveform of the type X pattern could be seen during ingestion within the xylem bundle sheath area. The Ph pattern always followed an SB pattern and was associated with a marked negative voltage drop. When this pattern was seen, the brown planthopper might be ingested plant sap from phloem sheath area.

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Studies on the Possible Mechanisms of Protective Activity Against $\alpha$-Amanitin Poisoning by Aucubin

  • Lee, Dong-Hee;Cho, In-Goo;Park, Moon-Soo;Kim, Ki-Nam;Chang, Il-Moo;Mar, Woong-chon
    • Archives of Pharmacal Research
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    • v.24 no.1
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    • pp.55-63
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    • 2001
  • Aucubin, an irdoid g1ucoside, was investigated to determine whether it has a stimulating effect on $\alpha$-amanitin excretion in $\alpha$-amanitin intoxicated rats, and whether there is binding activity to calf thymus DNA. High-performance liquid chromatography (HPLC) analysis of $\alpha$-amanitin in rat urine allowed quantitative measurement of the $\alpha$-amanitin concentration with a detection limit of 50${mu}g/ml$. In this system, a group treated with both $\alpha$-amanitin and aucubin showed that o(-amanitin was excreted about 1.4 times faster than in the $\alpha$-amanitin only treated group. Our previous results showed that the toxicity of $\alpha$-amanitin is due to specific inhibition of RNA polymerase activity and the resultant blockage of the synthesis of certain RNA species in the nucleus. However, no significant activity change on RNA polymerase from Hep G2 cells was observed when aucubin was treated with $\alpha$-amanitin at any concentration tested. Nevertheless, aucubigenin inhibited both DNA polymerase (IC50, 80.5${mu}g/ml$) and RNA polymerase (IC50, 135.0${mu}g/ml$) from the Hep G2 cells. The potential of both $\alpha$-amanitin and aucubin to interact with DNA were examined by spectrophotometric analysis. $\alpha$-Amanitin showed no significant binding capacity to calf thymus DNA, but aucubin was found to interact with DNA, and the apparent binding constant ($K_{app}$) and apparent number of binding sites per D7A phosphate ($B_{app}$) were 0.45$0.45{\times}$$10^4$ $M^{-1}$ and 1.25, respectively.

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Underdeveloped Embryos and Dormancy Type in Seeds of Two Heloniopsis Species Endemic to Korea

  • Lee, Seung Youn;Rhie, Yong Ha;Kim, Ki Sun
    • Horticultural Science & Technology
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    • v.32 no.4
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    • pp.550-557
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    • 2014
  • Heloniopsis koreana and Heloniopsis tubiflora (Melanthiaceae) are endemic herbaceous species of the Korean Peninsula. The Melanthiaceae family has been described as having seeds with small, underdeveloped embryos at the time of dispersal, and morphological (MD) or morphophysiological dormancy (MPD). However, there are few reports on embryo growth, morphology, and seed germination in Heloniopsis species. The aims of this study were to investigate embryo growth and seed dormancy, and to determine the type of dormancy exhibited by these species. The effects of incubation temperatures, light conditions, and gibberellic acid ($GA_3$) on dormancy break and seed germination were tested. Freshly matured seeds of the two species had small embryos that occupied about 9-11% of the length of the endosperm, and which increased by more than 300% in length before radicle emergence, indicating that the embryos are underdeveloped at the time of dispersal. Embryos in the seeds grew under warm temperature regimes (between $25/15^{\circ}C$ and $30/20^{\circ}C$). $GA_3$ application (tested only in the light) overcame seed dormancy and promoted germination. Approximately 30% of the seeds of H. koreana and approximately 40% of the seeds of H. tubiflora germinated in suitable environmental conditions (light and temperature) within 4 weeks. Therefore, 30-40% of the seeds of the two species exhibited MD, and the rest of the seeds had non-deep simple MPD. Light was found to be one of the critical factors for germination because no seed of either of the two Heloniopsis species germinated under constant dark conditions, and thus, these species have the potential to form a persistent soil seed bank. Understanding these germination requirements will help in development of effective strategies to increase the establishment of seedlings in their native habitat.

A Study on Rebuildup of 6MV X-ray by the Cavity (공동에 의한 6MV X선의 재선량증가 현상에 관한 연구)

  • Cho, Moon-June;Choi, Eun-Kyung;Chung, Woong-Ki;Kang, Wee-Saing;Park, Charn-Il
    • Radiation Oncology Journal
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    • v.7 no.1
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    • pp.113-121
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    • 1989
  • The inclusion of air filled cavities in treatment fields creates a potential dosimetric problem due to the rebuildup phenomenon near the air-tissue interface using a simulated phantom, such as air gap, air cylinder, and air cavity, the amount of rebuldup along the various field sizes and air cavity dimensions was measured. The results are as follows. 1. As the field size becomes larger in comparison with the cavity size, or as the cavity size gets bigger when the field size is equal to the cavity size, rebuildup decreases. 2. When the distance between the phantom surface and the air cavity is less than 1.5cm, there is prominent rebuildup. And when the distance is more than 1.5cm, rebuildup is relatively constant, 3. The change according to the depth of the cavity is affected by the field size and the cavity size, rebuildup usually increases when the depth of the cavity increases. 4. It is suggested that tissue equivalent material should be applied on the skin to make tissue thickness over the air cavity more than 1.5cm and that the field size should include the air cavity with at least 1cm margin.

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Minimizing the Water Leaching of Zincborate Glass by La2O3 Addition for LTCC Applications

  • Hong, Seung-Hyuk;Jung, Eun-Hee;Oh, Chang-Yong;Kim, Shin;Shin, Hyun-Ho
    • Journal of the Korean Ceramic Society
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    • v.45 no.3
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    • pp.157-160
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    • 2008
  • A series of $La_2O_3$-added zincborosilicate glasses was fabricated by systematically varying $La_2O_3$ addition up to 15mol% under the constraint of a ZnO:$B_2O_3$ ratio of 1:2. The degree of water leaching after ball milling of the prepared glasses in water medium was relatively quantified by the change in zinc peak intensity in energy dispersive spectroscopy. 8mol% of $La_2O_3$ was the most efficient addition in inhibiting the glass leaching by water. The role of $La_2O_3$ in inhibiting the leaching was explained in terms of change of structural units in the glass network. When the optimum 8mol% $La_2O_3$-added ZnO-$B_2O_3$ glass was used as sintering aid for $Al_2O_3$, the fabricated alumina-glass composite at $875^{\circ}C$ demonstrated dielectric constant of 6.11 and quality factor of 15470 GHz, indicating the potential of leaching-minimized $La_2O_3-ZnO-B_2O_3$ glass for application to low temperature co-firing ceramic technology.

Chemical Composition and Feeding Value of Chopped Date Fronds (CDF) as Affected by Urea and Date Syrup Extract Treatment

  • El Hag, M.G.;El Shargi, K.M.
    • Asian-Australasian Journal of Animal Sciences
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    • v.11 no.6
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    • pp.685-691
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    • 1998
  • In the first of two experiments, chemical composition (Ash, CP and CF contents), nutritive value (in vitro organic matter disappearance "lVOMD" and energy content "ME") and nitrogen retention of chopped date fronds (CDF) as affected by chemical treatment (CT) and storage duration (SD) were investigated. The experimental design was a completely randomized block, arranged in a $3{\times}4$ factorial, with 3 (CT) and 4 (SD) as the main factors using 2 replications / treatment. Three chemical treatments, were used : Control (With zero or no chemical treatment); treatment with 4% urea solution (w /w) and treatment with 4% urea + Date syrup extract (DS). The 4 (SD) were: Control (immediately after opening - without any storage or zero time storage); one month storage period; two months storage period and three months storage period. Both (CT) and (SD) had significant effects (p < 0.05) on CP and ash contents of the CDF, however there were no significant effects (p > 0.05) due to (CT) and (SD) on CF and nutritive value. High retention value (> 80%) for nitrogen was reported for the treated CDF, immediately after opening the incubated material (zero SD). However, nitrogen retention decreased with increasing (SD) to 67% after one month (SD) but tended to stay at a fairly constant level of 67% until 3 months of storage. In experiment 2, the feeding value of treated CDF was evaluated in comparison to Rhodes grass hay, using growing goats and sheep. A $4{\times}2$ factorial design was used (Four roughage sources were used : Rhodes grass hay, untreated CDF, urea-treated CDF and CDF treated with urea + DS with sheep and goats as two animal species, using three animals / treatment). Untreated CDF had a similar feeding value to Rhodes grass hay. However treatment of CDF with urea alone or with urea + DS depressed animal performance of both goats and sheep, apparently due to depression of feed intake (appetite). Feeding untreated CDF decreased feeding cost by 29% and cost/kg gain by 23%. CDF showed a good potential as a cheap local roughage and emergency feed for ruminants in the Sultanate.

Environmental Feature Causing a Bloom of the Novel Dinoflagellate Heterocapsa circularisquama (Dinophyceae) in Uranouchi Bay, Kochi Prefecture, Japan (일본 Kochi현 Uranouchi만의 와편모조류, Heterocapsa circularisquama (Dinophyceae) 적조발생에 대한 환경 고찰)

  • O, Seok-Jin;Ma,;O,;Mo,;U,
    • ALGAE
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    • v.18 no.4
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    • pp.281-288
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    • 2003
  • To study the environmental features causing a bloom of the novel dinoflagellate Heterocapsa circularisquama (Dinophyceae), hydrographic and chemical aspects were measured in the Uranouchi Bay, Kochi Prefecture, Japan, from January to December, 1997. The cell density of H. circularisquama increased rapidly in early October, and dropped sharply in mid-October. Growth rate of H, circularisquama during bloom period appeared 1.50 division day$^{-1}$ under high water temperature (25$^{\circ}C$) and salinity (32 psu) conditions. Althought the result from hydrographic aspect indicated good condition for their growth, dissolved inorganic phosphorus (DIP) concentration in surface layer before bloom formation was less than 0.70uM, which is lower than their half saturation constant(Ks). Dissolved inorganic nitrogen(DIN): DIP ratio was > 30, indicating potential P-limitation. However, before bloom formation period of H. circularisquama, DIP concentrations were high in bottom layer (> 4.0 uM). Some studies reported that H. circularisquama had the ability to migrate vertically and to utilize dissolved organic phosphorus (DOP). Thus, DIP in bottom layer might have been utilized by H. circularisquama for their growth.DOP might have weakly affected their growth because of low reactive DOP concentrations owing to low DOP concentration (ca. 0.39 uM). Thus, if nutrient condition of bottom layer in Uranuchi Bay is not improved, the outbreaks of H. circularisquama red tides may became an annual feature.

Modified Skyscraper Broadcasting Schemes for Periodic Broadcasting with VBR Video (VBR 리디오의 주기적 브로드캐스팅을 위한 수정 Skyscraper 브로드캐스팅 기법)

  • 이재동
    • Journal of Korea Multimedia Society
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    • v.5 no.5
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    • pp.571-581
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    • 2002
  • Many periodic broadcasting schemes for near VoD systems are proposed. Recently non-uniform segmentation schemes have been used to develop periodic broadcasting techniques for near VoD. These techniques give significant reductions in start-up latency as compared with more conventional uniform segmentation. However, all of these schemes assume that the videos are CBR-encoded. Since a CBR-encoded video has a target average tate than an VBR encoding, there is potential to obtain further Performance Improvements by using VBR videos. Unfortunately, however, the studies concerning broadcasting with VBR video ate rare and the existing techniques have the problem of virtual loss. In this paper, we modify Skyscraper Broadcasting Scheme for broadcasting with VBR videos which is a representative non-uniform segmentation scheme lot CBR videos. A VBR video can be transmitted at constant bit rate (CBR) by using prefetching. With this idea we propose Modified Skyscraper Broadcasting Schemes for VBR videos and make performance evaluation by simulation. We show that our schemes have a better performance than Skyscraper Broadcasting Scheme for CBR videos.

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Quantitative Changes in Phenolic Compounds of Safflower (Carthamus tinctorius L.) Seeds during Growth and Processing

  • Kim, Eun-Ok;Lee, Jun-Young;Choi, Sang-Won
    • Preventive Nutrition and Food Science
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    • v.11 no.4
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    • pp.311-317
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    • 2006
  • Phenolic compounds in safflower seeds were recently found to stimulate bone formation and increase plasma HDL cholesterol levels in estrogen deficient rats, and to inhibit melanin synthesis. Nine phenolic compounds: $N-feruloylserotonin-5-O-{\beta}-D-glucoside,\;8'-hydroxyarctigenin-4'-O-{\beta}-D-glucoside,\;luteolin-7-O-{\beta}-D-glucoside$, N-(p-coumaroyl)serotonin, N-feruloylserotonin, 8'-hydroxy arctigenin (HAG), luteolin (LT), $acacetin-7-O-{\beta}-D-glucuronide$ (ATG) and acacetin (AT), were quantified by HPLC in safflower (Carthamus tinctorius L.) seeds during growth and processing. During growth, levels of the nine phenolic compounds in the seeds increased progressively with increasing growth stages, reached a maximum on July 30 (42nd day after flowering), and then remained relatively constant. During the roasting process, levels of phenolic compounds, except HAG, LT and AT, generally decreased with increased roasting temperature and time, whereas those of HAG, LT and AT increased progressively with increased roasting temperature and time. During the steaming process, levels of other phenolic compounds except HAG and AT generally tended to increase with increased steaming time, whereas those of HAG and AT were scarcely changed. During the microwave treatment, quantitative changes of phenolic compounds were similar to the roasting process, although there were some differences in levels of phenolic compounds between two heat treatments. These results suggest that the steamed safflower seeds after harvesting on late July may be useful as potential dietary supplement source of phenolic compounds for prevention of several pathological disorders, such as atherosclerosis and osteoporosis and aging.

Tendencies of anti-fashion in Kinfolk magazine (Kinfolk 매거진에 나타난 안티패션(anti-fashion) 경향)

  • Lim, Ahreum;Yim, Eunhyuk
    • The Research Journal of the Costume Culture
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    • v.25 no.5
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    • pp.629-647
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    • 2017
  • As fashion has concentrated increasingly on inner values, it has become more directly connected with human life and society. This study analyzed anti-fashion, a movement that resists mainstream society and culture, which it views as causing inner conflicts such as competition, mammonism, consumerism, and egoism by fixating solely on the pursuit of growth and improvement. The study examined Kinfolk, an independent lifestyle magazine, to determine the essential values and principles that comprise this movement's refusal of mainstream modern society. The analysis of Kinfolk identified the following characteristics of, the Kinfolk lifestyle: essentialism, nature-friendliness, retro sensibilities, socio-ethical awareness, and diversity. Essentialism refers to the pursuit of essence, brevity, innovation based on tradition and slow life. Nature-friendliness involves communion with nature and humanity, animal-friendliness, de-industrialization, de-urbanization, and nomadic behavior. The components of the retro sensibility include nostalgia, and interests in vintage culture, and handcrafts. Diversity encompasses commonplaceness, various subcultures, agelessness, genderlessness, acceptance of other cultures, and new understanding. The analysis identified the tendencies of anti-fashion in Kinfolk magazine as simplicity, naturalism, resistance to novelty, ethics, and inclusiveness. Anti-fashion pursues the essential values of human life that have been lost or forgotten in modern society. It is important to pay constant attention to the values of minority, non-mainstream and indie cultures that represent anti-fashion. It exerts considerable influence and has great potential as an area for the development of various style-based paradigms rather than as a single fashion direction.