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Studies on the Pulping Characteristics of Larchwood (Larix leptolepis Gordon) by Alkaline Process with Additives (첨가제(添加劑) 알칼리 법(法)에 의한 일본 잎갈 나무의 펄프화(化) 특성(特性)에 관(關)한 연구(硏究))

  • Lim, Kie-Pyo;Shin, Dong-Sho
    • Journal of the Korean Wood Science and Technology
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    • v.7 no.2
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    • pp.3-30
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    • 1979
  • Larch ($\underline{Larix}$ $\underline{leptolepis}$ GORDON), one of the major afforestation species in Korea in view of its growing stock and rate of growth, is not favored as a raw material for pulp due to its low yield of pulp and difficulties with bleaching arising from the high content of extractives in wood, and the high heartwood ratio and the active phenolics, respectively. The purpose of this study is to investigate the characteristics of firstly pulping with various additives of cellulose protector for the yield of pulp, and secondly bleaching with oxygen for chlotination-alkali extraction of five stage-sequence to reduce chlorine compounds in bleaching effluents. The kraft cooking liquor for five age groups of larchwood was 18 percent active alkali with 25 percent sulfidity and 5 : 1 liquor-to-wood ratio, and each soda liquor for sap-and heart-wood of the 15-year-old larchwood was 18 percent alkali having one of the following cellulose protectors as the additive; magnesium sulfate ($MgSO_4$, 2.5%), zinc sulfate ($ZnSO_4$, 2.5%), aluminium sulfate ($Al_2(SO_4)_3$, 2.5%), potasium iodide (KI, 2.5%), hydroquinone (HQ, 2.5%), anthraquinone (AQ, 0.1%) and ethylene diamine (EDA, 2.5%). Then each anthraquinone-soda liquor for the determination of suitable cooking condition was the active alkali level of 15, 17 and 19 percent with 1.0, 0.5 and 0.1 percent anthraquinone, respectively. The cooking procedure for the pulps was scheduled to heat to 170$^{\circ}C$ in 90 minutes and to cook 90 minutes at the maximum temperature. The anthraquinone-soda pulps from both heartwood and sapwood of 15-year-old larchwood prepared with 0.5 percent anthraquinone and 18 percent active alkali were bleached in a four-stage sequency of OCED. (O: oxygen bleaching, D: chlorine dioxide bleaching and E: alkali extraction). In the first stage oxygen in atmospheric pressure was applied to a 30 percent consistency of pulp with 0.1 percent magnesium oxide (MgO) and 3, 6, and 9 percent sodium hydroxide on oven dry base, and the bleached results were compared pulps bleached under the conventional CEDED (C: chlorination). The results in the study were summarized as follows: 1. The screened yield of larch kraft pulp did not differ from particular ages to age group, but heartwood ratio, basic density, fiber length and water-extractives contents of wood and the tear factor of the pulp increased with increasing the tree age. The total yield of the pulp decreased. 2. The yield of soda pulp with various chemicals for cellulose protection of the 15-year-old larchwood increased slightly more than that of pure soda pulp and was slightly lower than that of kraft pulp. The influence of cellulose protectors was similar to the yield of pulps from both sapwood and heartwood. The effective protectors among seven additives were KI, $MgSO_4$ and AQ, for which the yields of screened pulp was as high as that of kraft pulp. Considering the additive level of protector, the AQ was the most effective in improving the yield and the quality of pulp. 3. When the amount of AQ increased in soda cooking, the yield and the quality of the pulp increased but rejects in total yield increased with decreasing the amount of active alkali from 19 to 15 percent. The best proportion of the AQ seemed to be 0.5 percent at 17 percent active alkali in anthraquinone-soda pulping. 4. On the bleaching of the AQ-soda pulp at 30 percent consistency with oxygen of atomospheric pressure in the first stage of the ODED sequence, the more caustic soda added, the brighter bleached pulp was obtained, but more lignin-selective bleaching reagent in proportion to the oxygen was necessary to maintain the increased yield with the addition of anthraquinone. 5. In conclusion, the suitable pulping condition for larchwood to improve the yield and quality of the chemical pulp to the level for kraft pulp from conventional process seemed to be. A) the selection of young larchwood to prevent decreasing in yield and quality due to the accumulation extractives in old wood, B) the application of 0.5 percent anthraquinone to the conventional soda cooking of 18 percent active alkali, and followed, C) the bleaching of oxygen in atmospheric pressure on high consistency (30%) with 0.1 percent magnesium oxide in the first stage of the ODED sequence to reduce the content of chlorine compounds in effluent.

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Effects of Y Chromosome Microdeletion on the Outcome of in vitro Fertilization (남성 불임 환자에서 Y 염색체 미세 결손이 체외 수정 결과에 미치는 영향)

  • Choi, Noh-Mi;Yang, Kwang-Moon;Kang, Inn-Soo;Seo, Ju-Tae;Song, In-Ok;Park, Chan-Woo;Lee, Hyoung-Song;Lee, Hyun-Joo;Ahn, Ka-Young;Hahn, Ho-Suap;Lee, Hee-Jung;Kim, Na-Young;Yu, Seung-Youn
    • Clinical and Experimental Reproductive Medicine
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    • v.34 no.1
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    • pp.41-48
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    • 2007
  • Objective: To determine whether the presence of Y-chromosome microdeletion affects the outcome of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) program. Methods: Fourteen couples with microdeletion in azoospermic factor (AZF)c region who attempted IVF/ICSI or cryopreserved and thawed embryo transfer cycles were enrolled. All of the men showed severe oligoasthenoteratoazoospermia (OATS) or azoospermia. As a control, 12 couples with OATS or azoospermia and having normal Y-chromosome were included. Both groups were divided into two subgroups by sperm source used in ICSI such as those who underwent testicular sperm extraction (TESE) and those used ejaculate sperm. We retrospectively analyzed our database in respect to the IVF outcomes. The outcome measures were mean number of good quality embryos, fertilization rates, implantation rates, $\beta$-hCG positive rates, early pregnancy loss and live birth rates. Results: Mean number of good quality embryos, implantation rates, $\beta$-hCG positive rates, early pregnancy loss rates and live birth rates were not significantly different between Y-chromosome microdeletion and control groups. But, fertilization rates in the Y-chromosome microdeletion group (61.1%) was significantly lower than that of control group (79.8%, p=0.003). Also, the subgroup underwent TESE and having AZFc microdeletion showed significantly lower fertilization rates (52.9%) than the subgroup underwent TESE and having normal Y-chromosome (79.5%, p=0.008). Otherwise, in the subgroups used ejaculate sperm, fertilization rates were showed tendency toward lower in couples having Y-chromosome microdeletion than couples with normal Y-chromosome. (65.5% versus 79.9%, p=0.082). But, there was no significance statistically. Conclusions: In IVF/ICSI cycles using TESE sperm, presence of V-chromosome microdeletion may adversely affect to fertilization ability of injected sperm. But, in cases of ejaculate sperm available for ICSI, IVF outcome was not affected by presence of Y-chromosome AZFc microdeletion. However, more larger scaled prospective study was needed to support our results.