• The Korean Journal of Physiology
• /
• v.30 no.1
• /
• pp.105-116
• /
• 1996

Rendering the brain ischemic would evoke the cerebral ischemic reflex which is characterized by an arterial pressor response, apnea and bradycardia. Since the rostral ventrolateral medulla (RVLM) is known to play a key role in the maintenance of normal cardiopulmonary activity, during the cerebral ischemic reflex some cardiac related cells should be excited and respiration related cells inhibited. In this context, the responses of RVLM neurons to systemie and focal hypoxia were analyzed in the present study. Twenty-five adult cats of either sex were anesthetized with ${\alpha}-chloralose$ and the single neuronal activities were identified from RVLM area. For the induction of focal hypoxia in the recording site, sodium cyanide was applied iontophoretically and for systemic hypoxia the animal was ventilated with nitrogen gas for a twenty-second period. Cellular activities were analyzed in terms of their discharge pattern and responses to the hypoxia by using post-stimulus time and single-pass time histograms. Of eighteen cardiac related cells recorded from the RVLM area, twelve cells were excited by iontophoresed sodium cyanide and of twenty-five respiration related cells, fourteen cells were excited by iontophoresed sodium cyanide. Remaining cells were either inhibited or unaffected. Eight of fifteen cells tested with iontophoresed sodium lactate were excited and remaining seven cells were inhibited. Systemic hypoxia induced by nitrogen gas inhalation elevated the arterial blood pressure, but excited, inhibited or unaffected the single neuronal activities. Some cells showed initial excitation followed by inhibition during the systemic hypoxia. Bilateral vagotomy resulted in a decrease of arterial pressor response to the systemic hypoxia, and a slight decrease in the rhythmicity related to cardiac and/or respiratory rhythms. The single neuronal responses to either systemic or focal hypoxia were not affected qualitatively by vagotomy. From the above results, it was concluded that the majority of the cardiac- and respiration- related neurons in the rostral ventrolateral medulla be excited by hypoxia, not through the mediation of peripheral chemoreceptors, and along with the remaining inhibited cells, all these cells be involved in the mediation of cerebral ischemic reflex.

• Environmental Engineering Research
• /
• v.24 no.2
• /
• pp.254-262
• /
• 2019

The impact of free cyanide ($CN^-$) and thiocyanate ($SCN^-$) on the $CN^-$ (CDO) and $SCN^-$ degraders (TDO) to nitrify and denitrify aerobically was evaluated under alkaline conditions. The CDO's were able to nitrify under cyanogenic conditions, achieving $NH_4{^+}-N$ removal rates above 1.66 mg $NH_4{^+}-N.L^{-1}.h^{-1}$, except when $CN^-$ and $SCN^-$ loading was 15 mg $CN^-/L$ and 50 mg $SCN^-.L^{-1}$, respectively, which slightly inhibited nitrification. The TDO's were able to achieve a nitrification rate of 1.59 mg $NH_4{^+}-N.L^{-1}.h^{-1}$ in the absence of both $CN^-$ and $SCN^-$, while the presence of $CN^-$ and $SCN^-$ was inhibitory, with a nitrification rates of 1.14 mg $NH_4{^+}-N.L^{-1}.h^{-1}$. The CDO's and TDO's were able to denitrify aerobically, with the CDO's obtaining $NO_3{^-}-N$ removal rates above 0.67 mg $NO_3{^-}-N.L^{-1}.h^{-1}$, irrespective of the tested $CN^-$ and $SCN^-$ concentration range. Denitrification by the TDO's was inhibited by $CN^-$, achieving a removal rate of 0.46 mg $NO_3{^-}-N.L^{-1}.h^{-1}$ and 0.22 mg $NO_3{^-}-N.L^{-1}.h^{-1}$ when $CN^-$ concentration was 10 and 15 mg $CN^-.L^{-1}$, respectively. However, when the CDO's and TDO's were co-cultured, the nitrification and aerobic denitrification removal rates were 1.78 mg $NH_4{^+}-N.L^{-1}.h^{-1}$ and 0.63 mg $NO_3{^-}-N.L^{-1}.h^{-1}$ irrespective of $CN^-$ and $SCN^-$ concentrations.

• Bulletin of the Korean Chemical Society
• /
• v.26 no.12
• /
• pp.2075-2077
• /
• 2005

• Bulletin of the Korean Chemical Society
• /
• v.32 no.6
• /
• pp.2070-2072
• /
• 2011

• 산업보건소식
• /
• no.47
• /
• pp.25-26
• /
• 1987

산업이 다양화.고도화됨에 따라 생산공정중에 불가피하게 발생되는 수많은 유해물질의 포집, 분석 방법에 대하여 우리실정에 알맞는 표준방법을 정함으로써 사업장 유해환경측정에 참고가 되고 나아가서 작업환경측정방법의 일원화를 도모하고자 노동부 국립노동과학연구소에서 수년간에 걸쳐 비교 연구하여 최근 보고한 바 있는 유해물질의 표준 실험 방법을 소개하고자 한다.

• Macromolecular Research
• /
• v.15 no.3
• /
• pp.202-204
• /
• 2007

• Applied Biological Chemistry
• /
• v.35 no.3
• /
• pp.170-172
• /
• 1992

Four types of polyphenol oxidase were isolated from the crude extract of a Ligularia fischeri by gel filtration on Sephadex G-150. Optimum pH and temperature for the activity of partially purified enzyme were 7.5 and $25^{\circ}C$, respectively. It was stable at temperature $40^{\circ}C$ when examined at pH 7.5 for 5 min, and lost 90% of its activity at $70^{\circ}C$ in 30 min at pH 7.5. The enzyme has good activity on catechol and chlorogenic acid but was inactive on dopamine.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.50 no.5
• /
• pp.301-308
• /
• 2005

This study was carried out to investigate the effect of stem-cutting (SC) length and portion on the major agronomic characters related with dry matter production and accumulation, and to examine their relation­ships in cassava. When cassava was planted with longer SCs or with older portion SCs, major canopy or source characters like leaf number and leaf area index developed excessively, while tuber yields could be reduced due to the decrease of root/shoot ratio, relative growth rate, root dry weight, and harvest index, particularly in the bitter varieties (high cyanide-level varieties). It was considered that the sweet varieties (low cyanide-level varieties) be early­bulked with higher tuber yield when they are planted with the 25-30 cm long SCs or with the SCs from young type to semi-mature portions of mother stems, while the bitter varieties with the 15-20 cm long SCs or with the SCs from semi-mature to hardwood portions of mother stems, respectively. However, a significant interaction between length and portion of SC was not observed in all agronomic characters.

• Resources Recycling
• /
• v.21 no.5
• /
• pp.3-17
• /
• 2012

Selective leaching processes for copper, gold, nickel, and cobalt have been investigated because there is an advantage of ammoniacal hydrometallurgy that metal such as copper could be selectively extracted restricting the dissolution of iron or calcium. In the present article, the studies for selective ammoniacal leaching of copper from motor scraps and waste printed circuit boards (PCBs), for ammoniacal leaching of gold to decrease the amount of cyanide used or to substitute cyanide by thiosulfate, and for ammoniacal leaching to recover nickel and cobalt from nickel oxide ore and intermidiate obtained from manganese nodule treatment process were summarized and further studies were proposed for domestic technology development for ammoniacal hydrometallurgy processes.

• Microbiology and Biotechnology Letters
• /
• v.16 no.3
• /
• pp.193-198
• /
• 1988

Catalase from Aspergillus niger KUF-04 was purified by five steps including gel filtration. The overall purification gave 64-fold purified preparation, a yield of about nine percent. The enzyme showed its maximum absorption at 406 nm. The optimum pH and temperature for the enzyme activity were around pH 7.0 and 6$0^{\circ}C$, respectively. The catalase was found to be stable in the range of pH 4.0 to pH 8.3 and temperature 2$0^{\circ}C$ to 6$0^{\circ}C$. However, it lost nearly all of the activity by heating at 8$0^{\circ}C$ for 20 min. The activity was markedly inhibited by hydroxylamine, potassium cyanide and sodium azide.