• Title/Summary/Keyword: transient time periods

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Climate Change Impacts on Optimum Ripening Periods of Rice Plant and Its Counter-Measure in Rice Cultivation (기후변화에 따른 벼 적정 등숙기간의 변동과 대책)

  • Yun Seong-Ho;Lee Jeong-Taek
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2000.11a
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    • pp.28-45
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    • 2000
  • It was unusual crop weather for 1998 and 1999 compared with normal in Korea. The consecutive days of the optimum ripening period for rice plant that had daily mean temperature 21-23C for 40 days after heading, increased with long anomalies in 1998-99. The air temperature during ripening period was much higher than the optimum temperature and lower sunshine hour than normal in the local adaptability tests of newly developed rice lines during those years. In response of rice cultivation to warming and cloudy weather during crop season, the yield shall be decreased. Most scientists agree that the rate of heating is accelerating and temperature change could become increasingly disruptive. Weather patterns should also become more erratic. Agrometeorologists could be analyzed yearly variations of temperature, sunshine hour and rainfall pattern focused on transient agroclimate change for last a decade. Rice agronomists could be established taking advantage of real time agricultural meteorology information system for fertilization, irrigation, pest control and harvest. Also they could be analyzed the characteristics of flowering response of the recommended and newly bred rice cultivars for suitable cropping plan such as cultural patterns and sowing or transplanting date. Rice breeders should be deeply considered introducing the characteristics of basic vegetative type of flowering response like Tonsil rices as prospective rice cultivars corresponding to global warming because of the rices needed higher temperature at ripening stage than Japonica rices, photoperiod sensitive and thermo-sensitive ecotypes

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Difference of Neuronal Recovery by Incubation Condition after Transient Hypoxia (배양조건에 의한 일과성 저산소상태 후 신경세포회복의 차이)

  • Moon, Soo-Hyeon;Oh, Jae-Inn;Park, Youn-Kwan;Chung, Heung-Sub;Lee, Hoon-Kap;Lee, Ki-Chan
    • Journal of Korean Neurosurgical Society
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    • v.29 no.9
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    • pp.1161-1170
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    • 2000
  • Objective : The transverse hippocampal slice is one of the most commonly studied in vitro models of mammalian brain physiology. However, despite its broad usage, there has been no standardization of slice preparation techniques or recording condition. It is well known that variations in recording conditions can result in profound different effects to neuronal responses. Evoked field potentials, recorded extracellularly, were used to investigate the effects of variations in hippocampal slice preparation protocol on hypoxia responses of CA1 neurones. Material & Methods : Before hypoxic injury, hippocampal slices were incubated for 4 hours. During incubation period, the slices were placed in a incubation chamber($21^{\circ}C$) for recovery from preparation injury and then transferred to recording chamber($34^{\circ}C$) for more recovery and baseline electric recording with current stimulation(0.1Hz). Various time periods in incubation chamber and recording chamber were applied to each experimental group(group 1=60min : 180min, group 2=90min : 150min, group 3=180min : 60min, time in incubation chamber : time in recording chamber) before 10 min hypoxia produced by replacing 95% $O_2$+5% $CO_2$ mixed gas to 95% $N_2$+5% $CO_2$ gas. Calcium, Magnesium ions and several drugs effecting on glutamate receptor also were studied. Recoveries from hypoxic injury of hippocampal slices were estimated by percent recovery of population spike(PS). Statistic analysis of study were performed using paired t-test. Results : The percent recovery of PS after 10min hypoxia was considerably enhanced by increasing the period of current stimulation during incubation period before hypoxic injury. Temperature effect on the result of this experiment was also studied(group 4) but the result from this showed no statistic significance. Low magnesium ion concentration of artificial CSF(Mg-free aCSF) during incubation period enhanced the recovery of PS but low calcium (calcium-free) and high magnesium ion concentration(2mM) reduced it after hypoxic injury. L-glutamate($100{\mu}M$) and AP-5($50{\mu}M$) had no effect on the recovery of PS but CNQX($10{\mu}M$) in artificial CSF during incubation period markedly enhanced the recovery of PS. Co-treatment of AP-5($50{\mu}M$), CNQX($10{\mu}M$) and high magnesium concentration(2mM) enhanced recovery of PS in immediate following period of hypoxic injury but the effect of cotreatment after then decayed rapidly and lost statistic significance. Conclusions : Judging from above results, the condition of baseline recording is important in observing the recovery of population spike after hypoxia, and the time and the condition should be controled more strictly to obtain reliable results.

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Changes of Lipid and Lipoprotein Compositions in Kawasaki Disease and its Impact on Cardiac Complications (가와사끼병에서 혈중 지질과 지단백의 변화와 심장 합병증에 미치는 영향에 관한 연구)

  • Yun, Sin Weon;Lee, Ho Seok;Kim, Dong Woon;Rhee, Kang Won;Jung, Young Soo
    • Clinical and Experimental Pediatrics
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    • v.48 no.12
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    • pp.1370-1377
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    • 2005
  • Purpose : Delineation of serum lipid and lipoprotein values in children after Kawasaki disease(KD) is important because of the predilection of this disease for the coronary arteries. Methods : The KD group was composed of 51 patients who were hospitalized from Jan. 2002 to Dec. 2003. Control was 25 patients with non-KD febrile illness. The levels of total lipid, phospholipid, triglyceride, HDL-cholesterol(HDL-C), LDL-cholesterol, total cholesterol, apolipoprotein A1(apo A1), apolipoprotein B, and Lipoprotein(a) were measured and compared with Echocardiographic findings. Measurements were obtained in four time periods: acute febrile, subacute, convalescent phase and 1 year after KD. Results : HDL-C($33.64{\pm}7.49mg/dL$ vs $50.43{\pm}14.41mg/dL$, P<0.01) and apo A1($99.75{\pm}6.39mg/dL$ vs $113.34{\pm}11.35mg/dL$, P<0.05) were decreased more in the acute febrile period of KD than in the control, but these changes were not correlated with cardiac complications. All lipid profiles were markedly elevated in the subacute stage and normalized in the convalescent stage; there were no changes until 1-year follow up. There were no significant differences in the changes of lipid profiles, including Lp(a) and coronary dilatation, in any time periods. Conclusion : KD is associated with important abnormalities in lipid metabolism, but these changes were transient and appear to be due to the disease itself. These data lead us to infer that KD dose not cause such permanent changes in lipid abnormalities as to be considered a risk factor for atherosclerosis, beyond that caused by the disease itself.

EFFECT OF SOFT-START CURING ON THE CONTRACTION STRESS OF COMPOSITE RESIN RESTORATION POLYMERIZED WITH LED AND PLASMA CURING UNIT (LED와 플라즈마 광원의 완속기시 광중합 방식이 복합레진의 수축응력에 미치는 영향)

  • Chung, Yang-Seok;Lee, Nan-Young;Lee, Sang-Ho
    • Journal of the korean academy of Pediatric Dentistry
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    • v.34 no.4
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    • pp.623-631
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    • 2007
  • Effect of Soft-start curing on the contraction stress of composite resin restoration polymerized with LED and plasma curing unit The purpose of this study was to evaluate the influence of soft-start light curing on contraction stress and hardness of composite resin. Composite resin (Filtek $Z-250^{TM}$, 3M ESPE, USA) was cured using the one-step continuous curing method with three difference light sources ; conventional halogen light ($XL3000^{TM}$, 3M ESPE, USA) cure for 40 seconds at $400 mw/cm^2$, LED light (Elipar Freelight $2^{TM}$, 3M-ESPE, USA) cure for 20 seconds at $800\;mW/cm^2$ a and plasma arc light ($Flipo^{TM}$, LOKKI, France) cure for 12 seconds at $1300 mW/cm^2$. For the soft-start curing method ; LED light (Elipar Freelight $2^{TM}$, 3M-ESPE, USA) cure exponential increase with 5 seconds followed by 17 seconds at $800\;mW/cm^2$ and plasma arc light ($Flipo^{TM}$, LOKKI, France) cure 2 seconds light exposure at $650\;mW/cm^2$ followed by 11 seconds at $1300\;mW/cm^2$. The strain guage method was used for determination of polymerization contraction. Measurements were recorded at each 2 second for the total of 800 seconds including the periods of light application. Obtained data were analyzed statically using Repeated measures ANOVA, One way ANOVA, and Tukey test. The results of present study can be summarized as follows: 1. Composite resin restoration showed transient expansion just after irradiation of curing light. Contraction stress was increased rapidly at the early phase of polymerization and reduced slowly as time elapsed (P<0.05). 2. Contraction stress was not revealed significant difference between Halogen curing light groups and LED and Plasma Light curing with soft-start group (P>0.05). 3. LED and Plasma Light curing with soft-start showed lower contraction stress than the one-step continuous light curing (P<0.05).

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LINAC-based Stereotactic Radiosurgery for Meningiomas (수막종에 대한 선형가속기형 정위방사선수술)

  • Shin Seong Soo;Kim Dae Yong;Ahn Yong Chan;Lee Jung Il;Nam Do-Hyun;Lim Do Hoon;Huh Seung Jae;Yeo Inhwan J;Shin Hyung Jin;Park Kwan;Kim BoKyoung;Kim Jong Hyun
    • Radiation Oncology Journal
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    • v.19 no.2
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    • pp.87-94
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    • 2001
  • Purpose : To evaluate the role of LINAC-based stereotactic radiosurgery (SRS) in the management of meningiomas, we reviewed clinical response, image response, neurological deficits for patients treated at our institution. Methods and materials : Between February 1995 and December 1999, twenty-six patients were treated with SRS. Seven patients had undergone prior resection. Nineteen patients received SRS as the initial treatment. There were 7 male and 19 female patients. The median age was 51 years (range, $14\~67\;years$). At least one clinical symptom presented at the time of SRS in 17 patients and cranial neuropathy was seen in 7 patients. The median tumor volume was $4.7\;cm^3\;(range,\;0.7\~16.5\;m^3)$. The mean marginal dose was 15 Gy (range, $10\~20\;Gy$), delivered to the $80\%$ isodose surface (range, $46\~90\%$). The median clinical and imaging follow-up periods were 27 months (range, 1-71 months) and 25 months (range, $1\~52\;months$), respectively. Results : Of 14 patients who had clinical follow-up of one year or longer, thirteen patients $(93\%)$ were improved clinically at follow-up examination. Clinical symptom worsened in one patient at 4 months after SRS as a result of intratumoral edema, who underwent surgical resection at 7 months. OF 14 patients who had radiologic follow-up of one year or longer, tumor volume decreased in 7 patients $(50\%)$ at a median of 11 months (range, $6\~25\;months$), remained stable in 6 patients $(43\%)$, and increased in one patient $(7\%)$, who underwent surgical resection at 44 months. New radiation-induced neurological deficits developed in six patients $(23\%)$. Five patients $(19\%)$ had transient neurological deficits, completely resolved by conservative treatment including steroid therapy. Radiation-induced brain necrosis developed in one patient $(3.8\%)$ at 9 months after SRS who followed by surgical resection of tumor and necrotic tissue. Conclusions : LINAC-based SRS proves to be an effective and safe management strategy for small to moderate sized meningiomas, inoperable, residual, and recurrent, but long-term follow-up will be necessary to fully evaluate its efficacy. To reduce the radiation-induced neurological deficit for large size meningioma and/or in the proximity of critical and neural structure, more delicate treatment planning and optimal decision of radiation dose will be necessary.

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