• Title/Summary/Keyword: water quality variation

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Change in Fish Species Composition in the Saemangeum Reservoir after the Construction of Dike in 2006-2007 (새만금 방조제 물막이 완공 후인 2006-2007년 새만금호 어류 종조성의 변화)

  • Lee, Tae-Won;Hwang, Hak-Bin;Hwang, Sun-Wan
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.12 no.3
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    • pp.191-199
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    • 2007
  • Seasonal variation in species composition of fish in the Saemangeum Reservoir was determined using seasonal samples collected by an otter trawl from April 2006 to February 2007 after the dike construction, and compared with the data obtained during the dike construction in 2001-2002. A total of 35 species, 8,960 individuals and 53,084.4 g of fish were collected during the study. Of the fish collected, brackish and coastal fishes such as Konosirus punctatus, Synechogobius hasta and Repomucenus lunatus, and migrant fishes such as Engraulis japonicus and Scomberomorus niphonius predominated in abundance accounting for 95% in the total number of individuals. Fish species composition and abundance showed a similar seasonal trend to those in the other western coastal waters of Korea. The resident species were mainly collected in spring and in autumn. The number of species and biomass were high in summer by the large amount of catch of migrating species. Catch was low in winter and only 2 species were collected. A brackish and coastal fish, K. punctatus and two migrant fishes, E. japonicus and S. niphonius were abundantly collected after the dike construction. However, the dominant fishes during the dike construction such as Leiognathus nuchalis, Neosalanx jordani and Chaeturichthys stigmatias were rarely collected. Fish density was $1,149\;inds./10,000m^2\;and\;12,644g/10,000m^2$ during the dike construction, and increased 6 times in the number of individuals ($7,467\;inds./10,000m^2$) and 3 times in biomass ($44,237g/10,000m^2$) after the dike construction. Annual species richness (R) and species diversity (H') decreased from R=0.0160 and H'=2.47 during the dike construction in 2001-2002 to R=0.0038 and H'=1.11 after dike construction in 2006-2006, respectively. These changes seemed to be related to the reduction of the saline area and degradation of water quality in Semangeum Reservoir after the dike construction.

The Impact of Bladder Volume on Acute Urinary Toxicity during Radiation Therapy for Prostate Cancer (전립선암의 방사선치료시 방광 부피가 비뇨기계 부작용에 미치는 영향)

  • Lee, Ji-Hae;Suh, Hyun-Suk;Lee, Kyung-Ja;Lee, Re-Na;Kim, Myung-Soo
    • Radiation Oncology Journal
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    • v.26 no.4
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    • pp.237-246
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    • 2008
  • Purpose: Three-dimensional conformal radiation therapy (3DCRT) and intensity-modulated radiation therapy (IMRT) were found to reduce the incidence of acute and late rectal toxicity compared with conventional radiation therapy (RT), although acute and late urinary toxicities were not reduced significantly. Acute urinary toxicity, even at a low-grade, not only has an impact on a patient's quality of life, but also can be used as a predictor for chronic urinary toxicity. With bladder filling, part of the bladder moves away from the radiation field, resulting in a small irradiated bladder volume; hence, urinary toxicity can be decreased. The purpose of this study is to evaluate the impact of bladder volume on acute urinary toxicity during RT in patients with prostate cancer. Materials and Methods: Forty two patients diagnosed with prostate cancer were treated by 3DCRT and of these, 21 patients made up a control group treated without any instruction to control the bladder volume. The remaining 21 patients in the experimental group were treated with a full bladder after drinking 450 mL of water an hour before treatment. We measured the bladder volume by CT and ultrasound at simulation to validate the accuracy of ultrasound. During the treatment period, we measured bladder volume weekly by ultrasound, for the experimental group, to evaluate the variation of the bladder volume. Results: A significant correlation between the bladder volume measured by CT and ultrasound was observed. The bladder volume in the experimental group varied with each patient despite drinking the same amount of water. Although weekly variations of the bladder volume were very high, larger initial CT volumes were associated with larger mean weekly bladder volumes. The mean bladder volume was $299{\pm}155\;mL$ in the experimental group, as opposed to $187{\pm}155\;mL$ in the control group. Patients in experimental group experienced less acute urinary toxicities than in control group, but the difference was not statistically significant. A trend of reduced toxicity was observed with the increase of CT bladder volume. In patients with bladder volumes greater than 150 mL at simulation, toxicity rates of all grades were significantly lower than in patients with bladder volume less than 150 mL. Also, patients with a mean bladder volume larger than 100 mL during treatment showed a slightly reduced Grade 1 urinary toxicity rate compared to patients with a mean bladder volume smaller than 100 mL. Conclusion: Despite the large variability in bladder volume during the treatment period, treating patients with a full bladder reduced acute urinary toxicities in patients with prostate cancer. We recommend that patients with prostate cancer undergo treatment with a full bladder.