• Title/Summary/Keyword: burst index

Search Result 80, Processing Time 0.031 seconds

Short-segment Pedicle Instrumentation of Thoracolumbar Burst-compression Fractures; Short Term Follow-up Results

  • Shin, Tae-Sob;Kim, Hyun-Woo;Park, Keung-Suk;Kim, Jae-Myung;Jung, Chul-Ku
    • Journal of Korean Neurosurgical Society
    • /
    • v.42 no.4
    • /
    • pp.265-270
    • /
    • 2007
  • Objective : The current literature implies that the use of short-segment pedicle screw fixation for spinal fractures is dangerous and inappropriate because of its high failure rate, but favorable results have been reported. The purpose of this study is to report the short term results of thoracolumbar burst and compression fractures treated with short-segment pedicle instrumentation. Methods : A retrospective review of all surgically managed thoracolumbar fractures during six years were performed. The 19 surgically managed patients were instrumented by the short-segment technique. Patients' charts, operation notes, preoperative and postoperative radiographs (sagittal index, sagittal plane kyphosis, anterior body compression, vertebral kyphosis, regional kyphosis), computed tomography scans, neurological findings (Frankel functional classification), and follow-up records up to 12-month follow-up were reviewed. Results : No patients showed an increase in neurological deficit. A statistically significant difference existed between the patients preoperative, postoperative and follow-up sagittal index, sagittal plane kyphosis, anterior body compression, vertebral kyphosis and regional kyphosis. One screw pullout resulted in kyphotic angulation, one screw was misplaced and one patient suffered angulation of the proximal segment on follow-up, but these findings were not related to the radiographic findings. Significant bending of screws or hardware breakage were not encountered. Conclusion : Although long term follow-up evaluation needs to verified, the short term follow-up results suggest a favorable outcome for short-segment instrumentation. When applied to patients with isolated spinal fractures who were cooperative with 3-4 months of spinal bracing, short-segment pedicle screw fixation using the posterior approach seems to provide satisfactory result.

Effect of Coatings of Oxidized Starch on Properties of Linerboard (산화전분 코팅이 골판지 원지의 물성에 미치는 영향)

  • Ahn, Byoung-Kuk;Ahn, Won-Yung
    • Journal of the Korean Wood Science and Technology
    • /
    • v.28 no.1
    • /
    • pp.71-79
    • /
    • 2000
  • Two linerboards consisting of corrugated board were coated with oxidized starch solutions to investigate the change of their properties and analyze the effect of coating on them. The coating of linerboards with oxidized starch resulted in improvement in the properties related to corrugated board properties by increasing fiber bonding and rigidity. The improvement of ring crush strength by coating was greater in inside linerboard than in outside linerboard. Burst index of linerboards rapidly increased with an initial increase of coating weight, but as the coating weight further increased, there was no increase in burst index. Coating on linerboards with oxidized starch at low coating weight improved stiffness of them. There were no significant changes in tearing resistance of linerboards by coating of oxidized starch. The coating resulted in increase in air resistance and sizing degree of linerboards.

  • PDF

Effect of the Inhibition of Phospholipase $A_2$ in Generation of Free Radicals in Intestinal Ischemia/Reperfusion Induced Acute Lung Injury

  • Lee, Young-Man;Park, Yoon-Yub;Kim, Teo-An;Cho, Hyun-G.;Lee, Yoon-Jeong;Repine, John E.
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.3 no.3
    • /
    • pp.263-273
    • /
    • 1999
  • The role of phospholipase $A_2\;(PLA_2)$ in acute lung leak induced by intestinal ischemia was investigated in association with neutrophilic respiratory burst. To induce lung leak, we generated intestinal ischemia for 60 min prior to the 120 min reperfusion by clamping superior mesenteric artery in Sprague-Dawley rats. Acute lung leak was confirmed by the increased lung leak index and protein content in bronchoalveolar fluid. These changes were inhibited by mepacrine, the non-specific $PLA_2$ inhibitor. The lung myeloperoxidase (MPO) activity denoting the pulmonary recruitment of neutrophils was increased by intestinal I/R, but decreased by mepacrine. Simultaneously, the number of leukocytes in bronchoalveolar fluid was increased by intestinal ischemia/reperfusion (I/R) and decreased by mepacrine. Gamma glutamyl transferase activity, an index of oxidative stress in the lung, was increased after intestinal I/R but decreased by mepacrine, which implicates that $PLA_2$ increases oxidative stress caused by intestinal I/R. The $PLA_2$ activity was increased after intestinal I/R not only in the intestine but also in the lung. These changes were diminished by mepacrine. In the cytochemical electron microscopy to detect hydrogen peroxide, intestinal I/R increased the generation of the hydrogen peroxide in the lung as well as in the intestine. Expression of interleukin-1 (IL-1) in the lung was investigated through RT-PCR. The expression of IL-1 after intestinal I/R was enhanced, and again, the inhibition of $PLA_2$ suppressed the expression of IL-1 in the lung. Taken together, intestinal I/R seems to induce acute lung leak through the activation of $PLA_2$, the increase of IL-1 expression associated with increased oxidative stress by neutrophilic respiratory burst.

  • PDF

EVALUATIN OF NALITA WOOD(Trema orientalis) AS SOURCE OF FIBER FOR PARERMAKING

  • Jahan, M. Sarwar;Mun, Sung-Phil
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
    • /
    • 2003.11a
    • /
    • pp.17-26
    • /
    • 2003
  • Nalita wood(Trema orientalis) is one of the fastest growing woods in the world. It may be a viable species for pulpwood. The physical, chemical and morphological properties of Nalita were studied. The total lignin, pentosan and holocellulose content in Nalita wood were 24.7%, 22% and 81.2%, respectively. Its fiber length was about 0.92 mm, which are comparable to Acacia mangium. Nitrobenzene oxidation of Nalita wood meal indicated that the guaciayl and syringyl unit were the major constituent of Nalita lignin. Nalita produced 50% pulp yield at Kappa number 21 in soda-anthraquinone process. The strength properties of Nalita pulp were comparable to other tropical hardwood pulp. At $40_{\circ}$ SR, the breaking length, burst index, tear index and total energy absorption were 6000 m, $3.5kPa{\cdot}m^2/g\;and\;7.0mN{\cdot}m^2/g\;and\;75J/m^2$, respectively.

  • PDF

Pulping Characteristics of Bamboo(Bambusa procera acher) Grown in Vietnam (베트남산 대나무의 펄프화 특성)

  • Won, Jong-Myoung;Kim, Min-Hyun
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.41 no.4
    • /
    • pp.52-57
    • /
    • 2009
  • Soda and kraft pulping experiments were carried out in order to investigate the pulping characteristics of bamboo grown in Vietnam. The merit of kraft pulping was not observed for bamboo pulping from the viewpoint of delignification and screened pulp yield. The improvements of delignification during soda and kraft pulping of bamboo were observed by the addition of AQ. The bamboo pulp leaded the bulkier structure than those made from SwBKP and HwBKP. The average fiber length was 1.62mm which is shorter than those of SwBKP, but longer than those of HwBKP. It was found that the physical properties of bamboo pulp sheet could be varied by the pulping method, cooking condition, AQ addition, bleaching and refining etc.

Effect of Urea Addition on Soda Pulping of Oak Wood

  • Cho, Nam-Seok;Matsumoto, Yuji
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
    • /
    • 2006.06b
    • /
    • pp.285-290
    • /
    • 2006
  • As an alternative method to solve air pollution problem and difficulty of pulp bleaching of kraft pulping process, NaOH-Urea pulping was applied. The properties of NaOH-Urea pulp were compared to those of NaOH and kraft pulps. Addition of urea in low alkali charges retarded delignification rate compared to NaOH pulping. But, in high alkali application, delignification was significantly enhanced not from the addition of urea but from the high alkalinity. It was disclosed that urea did not participate on delignification reaction by the experiment using lignin model compound. Compared to paper strengths at the same level of sheet density, NaOH-Urea pulp gave as almost same breaking length and tensile index as those of kraft pulp. Especially tensile energy absorption and burst index were higher than those of kraft pulp.

  • PDF

Bio-Soda Pulping of Rice Straw with Pleurotus cornucopiae under Atmospheric Pressure

  • Ju, Yong-Chan;Kang, Jin-Ha
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.35 no.5
    • /
    • pp.62-71
    • /
    • 2003
  • This study was carried out to develop the bio-chemical pulping method to enhance the energy saving and decrease the capital cost through the soda pulping under atmospheric pressure ($100^{\circ}C$). Nonwood substrates, rice straw, were pretreated by white-rot fungi, Pleurotus cornucopiae. Several basic pieces of data that can be applied in soda pulping were acquired. The results of this study were as follows. Under the conditions without any nutrients or with glucose, N and glucose + N, the weight losses of rice straws inoculated by Pleurotus cornucopiae were 12.1∼32.6 %, 12.0∼26.3 %, 13.0∼25.4 % and 15.3∼24.7 % for 5, 10, 15, 20, 25 and 30 days incubation periods respectively. The more the fungal incubation was extended, the more the weight losses were gained. The yield of untreated rice straw was 54.8 % after pulping. When any nutrients was not added or glucose, N and glucose + N were added for the pretreatment, the total yields were ranged to 57.3∼42.9 %, 51.0∼43.3 %, 51.7∼43.9 % and 52.1∼46.1 % for 5 different incubation periods respectively. The yields were gradually decreased based on the extending of the incubation periods. The physical properties of the rice straw soda pulp without fungal treatment, the density, breaking length, burst index, tear index and folding endurance were 0.24g/㎤, 2.32 Km, 0.91 kPaㆍ$m^2$/g, 46.7 mNㆍ$m^2$/g and 21 times, respectively. In the case of pretreatment without any nutrients or with glucose, N and glucose + N as nutrients, the density was 0.24g/㎤, the breaking length was 3.30∼6.46 Km, the burst index was 1.36∼3.01 kPaㆍ$m^2$/g, the tear index was 33.0∼57.0 mNㆍ$m^2$/g and the folding endurance was 14∼381 times at most incubating periods, when pulping was done. The physical properties were increased as the incubation duration was extended. Especially, when N and glucose + N were added, the physical properties showed superior results during each incubation period.

Modification of KOCC with Ultrasonic Wave Treatment (초음파처리에 의한 KOCC의 개질)

  • Ming, He;Lee, Yong-Kyu;Won, Jong Myoung
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.45 no.5
    • /
    • pp.44-48
    • /
    • 2013
  • Ultrasonic treatment of KOCC was tried to explore the possibility for improvement of KOCC quality as a raw material for making industrial packaging paper and paperboard. The effect of pH, stock consistencies and treatment times on the ultrasonic response of KOCC were investigated. WRV, apparent density, tensile index and burst index were improved as pH of KOCC slurry is increased. However highest tear index and stiffness were obtained at pH 8. It was also found that the highest WRV and strength properties could be obtained at 0.5% of KOCC consistency during ultrasonic treatment. WRV and most strength properties were improved with ultrasonic treatment time. It was found that ultrasonic treatment can be used as a useful mean for KOCC modificaton.

Effect of Molar Ratios of DES on Lignin Contents and Handsheets Properties of Thermomechanical Pulp (TMP의 LB 공융용매 처리 시 젖산/베타인 몰 비율이 리그닌 함량 및 수초지 특성에 미치는 영향)

  • Choi, Kyoung-Hwa;Lee, Myoung-Ku;Ryu, Jeong-Yong
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.48 no.2
    • /
    • pp.28-33
    • /
    • 2016
  • This study was conducted to investigate the effects of deep eutectic solvent (DES) treatment on properties of TMP fibers and handsheets. DES was prepared by mixing of lactic acid and betaine (L and B), and the molar ratio of these two components mixtures was controlled to 2:1 (L:B=2:1) and 5:1 (L:B=5:1). As results, lignin was partly extracted from the TMP fibers. Especially, the delignification of TMP samples was promoted according to the increase of the molar ratio of lactic acid. Except for tear index, both tensile index and burst index of handsheets were increased when higher molar ratio of lactic acid was mixed for DES preparation. However, the LB DES treatment of TMP fibers didn't give any effect on the optical properties of TMP handsheets. The plausibility of TMP fiber was to be enhanced by LB DES treatment.

Bleaching of Oak Kraft Pulp by O, Eo and C/D Stage (O, Eo 및 C/D단계를 이용한 신갈나무 크라프트펄프표백)

  • 김동호;백기현
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.29 no.3
    • /
    • pp.43-50
    • /
    • 1997
  • The purpose of this study was to decrease pollutants of effluents from KP bleaching. Multistage bleaching that combined with O, Eo, and C/D stage was conducted, after optimum bleaching conditions of O, Eo, and C/D stage were determined. Moreover the properties for bleached pulps and pollution level of bleaching effluent were measured by each standard method. Due to increase on the brightness and delignification of pulps by O, Eo, and C/D stage bleaching. It was possible that bleaching sequences were reduced from five stage to four stage. In addition to, OC/DEoD and OC/DEopD bleaching sequences had higher brightness than CEDED bleaching sequence. The pulps bleached by O and Eo stage had higher in tensile index than conventional bleaching sequences with the similar results in burst and tear index. While each bleaching sequences had little differences, bleaching sequences with Eo stage had higher in physical properties than with Eop stage. The pollution level measured by Chemical Oxygen Demand(COD), Biochemical Oxygen Demand(BOD) and Color of bleaching effluents were much lower in combined bleaching sequences of O, Eo and C/D stage than that of CEDED sequence. Particularly, a pollution index of bleaching effluents generated by C/DEoDEB and OC/DEopDED bleaching sequences were lower than that from the other bleaching sequences.

  • PDF