• Journal of the Korean Society of Propulsion Engineers
• /
• v.15 no.4
• /
• pp.85-93
• /
• 2011

A parametric study is conducted for the design of segmented arc plasma torch with the input power and current of 0.4 MW and 300 A, respectively. For this purpose, we use the analytical relationship between input power, current condition, plasma temperature, inner diameter (R) and length (L) of the torch constrictor based on arc channel model. The results reveal that arc plasma temperatures increase monotonically as ��L increases or R decreases for the ranges of R ${\leq}$ 7.5 mm and L ${\leq}$ 1.25 m. For larger valuse of ��R and L than 7.5 mm and 1.25 m, respectively, however, they show non-linear behavior corresponding to the variations of ��L, which stands for the generation of unstable arc plasma. From this parametric study, optimum ranges of R and L are suggested as 5.5 mm ${\leq}$ R ${\leq}$ 7.5 mm and 0.25 m ${\leq}$ L ${\leq}$ 0.5 m for 0.4 MW class segmented arc plasma torch, under which stable arc plasma can be achieved at the input currents of ~300 A.

• The Korean Journal of Pain
• /
• v.21 no.1
• /
• pp.44-50
• /
• 2008

Background: The use of regional local anesthetics or opioids during laparoscopic cholecystectomy (LC), in combination with general anesthesia, has been investigated in several interventional studies. Methods: We studied a total of 240 (n = 60, each) patients who were undergoing LC, and they received local infiltration and intraperitoneal instillation with normal saline or 0.25% levobupivacaine 60 ml. Group R (S) received infiltration of normal saline 20 ml before incision and at the end of surgery and then 40 ml intraperitoneal instillation after removal of the gall bladder under remifentanil-based anesthesia. Group R (L) received 0.25% levobupivacaine instead of normal saline in the same method like group R (S). Group S (S) received the same method as group R (S) under sevoflurane based anesthesia in place of remifentanil. Group S (L) received 0.25% levobupivacaine instead of normal saline with the same method as group S (S). Pain was assessed on a visual analog scale at 1, 6, 12 and 24 hours after operation. Results: The pain intensity of Group R (L) was significantly lower than that of group R (S), and the the incisional pain of group S (L) was significantly lower than that of group S (S) in the first six hours. The time delay to first operative analgesics in group R (S) and group S (S) was significantly shorter than that of group R (L) and group S (L). Conclusions: Infiltration and instillation of levobupivacaine reduced the postoperative pain and remifentanil did not increase the pain severity and opioid requirement when performing the LC.

• Journal of the Korean Applied Science and Technology
• /
• v.32 no.4
• /
• pp.781-788
• /
• 2015

In this study, the antioxidative effects of 50% ethanol extract, ethylacetate fraction and aglycone fraction obtained from dried whole plant of Solanum nigrum L. were investigated. The free radical scavenging activities ($FSC_{50}$) were $215.46{\mu}g/mL$, $42.43{\mu}g/mL$ and $52.28{\mu}g/mL$, respectively. Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) in $Fe^{3+}-EDTA/H_2O_2$ system were $25.25{\mu}g/mL$, $7.05{\mu}g/mL$ and $6.25{\mu}g/mL$, respectively. 50% ethanol extract and aglycone fraction showed the cellular protective effect against $^1O_2$ induced cellular damage of rabbit erythrocytes at $5{\sim}25{\mu}g/mL$, but not at high concentrations. These results indicated that S. nigrum extract/fractions could be used as an antioxidative agent. However, it could induce cellular damage at high concentrations. In conclusion, a special caution is required to use S. nigrum extracts as a cosmetic ingredient.

• Journal of the Korean Data and Information Science Society
• /
• v.3 no.1
• /
• pp.25-31
• /
• 1992

Some results relating to $C_{0}(R)\;and\;L^{1}(R)$ spaces with application to kernel density estimators will be introduced. First, random elements in $C_{0}(R)\;and\;L^{1}(R)$ are discussed. Then, complete convergence limit theorems are given to show that these results can be used in establishing uniformly consistency and $L^{1}$ consistency.

• Proceedings of the KSME Conference
• /
• 2005.11a
• /
• pp.25.1-25.1
• /
• 2005

• Korean Journal of Clinical Pharmacy
• /
• v.16 no.1
• /
• pp.28-33
• /
• 2006

The stability of cefditoren in three kinds of oral liquid preparations at 4 and $25^{\circ}C$ was studied for 90 days. Two tablets of 100 mg cefditoren pivoxil were mixed with 200 mL of each oral liquid syrup, which is Pebron syrup (oxolamine citrate 10 mg/mL), $Mucopect^{(R)}$ syrup (ambroxol hydrochloride 3 mg/mL) or $Tyrenol^{(R)}$ suspension (acetaminophen encapsulated 32 mg/mL). Three samples of each formulation were refrigerated $(4^{\circ}C)$ and three were stored at room temperature $(25^{\circ}C)$. At predetermined time, samples were assayed by stability-indicating HPLC method. The chromatographic analysis after deliberate degradation showed no evidence of any breakdown product likely to interfere with the chromatographic peak of the parent substance. The relation between cefditoren pivoxil concentration and peak area was linear from 10 to $150{\mu}g/mL\;(r^2=0.9998)$. The analysis method was precise, with coefficients of variation no greater than 3.6%. Cefditoren was stable in $Mucopect^{(R)}$ syrup up to 4 weeks regardless of the temperature; in $Tyrenol^{(R)}$ suspension and Pebron syrup, it was stable for at least 28 and 45 days, and 7 and 45 days at 25 and $4^{\circ}C$, respectively. The percentages of initial cefditoren concentration remaining after 90 days were $51.5{\pm}1.8\;and\;80.9{\pm}5.6%,\;61.7{\pm}7.8\;and\;70.2{\pm}7.3%,\;and\;39.9{\pm}3.2\;and\;81.4{\pm}5.5%$ in $Mucopect^{(R)}$ syrup, $Tyrenol^{(R)}$ suspension and $Pebron^{(R)}$ syrup at 25 and $4^{\circ}C$, respectively. The pH variations of all test solutions were minimal, which was within 0.5. The results indicated that the stability of cefditoren was significantly affected by liquid solutions mixed with cefditoren, and storage tempertature.

• Journal of Environmental Health Sciences
• /
• v.10 no.2
• /
• pp.89-97
• /
• 1984

The possible effects of garlic (Aliium sativurn L.) extract on growth and aflatoxin production by Aspergillus parasiticus R- 716 were investigated. Various solvent extracts of garlic strongly inhibited growth and sporulation by Aspergillus parasiticus R-716, and effective solvents used for extraction of garlic were chloroform, benzene, and water-chloroform. The growth and aflatoxin production decreased with the increase in extract concentration, and extract equivalent 1.5g of raw garlic weight in 25ml SLS medium completely inhibited, and at a level of 1.25g garlic, total aflatoxin was reduced 64% (472 ${\mu}g$/25ml) of that produced in the control (1, 352 ${\mu}g$/25 ml). During cultivation inhibitory rate of growth was reduced from 89.1% to 40% and aflatoxin $B_2$, $G_1$ production increased with the laps of time. Especially garlic extract appeared to have a stimulatory effect on lipid accumulation on the contrary aflatoxin production.

• Korean Journal of Environmental Biology
• /
• v.37 no.3
• /
• pp.372-379
• /
• 2019

We evaluated the toxic effects of phenanthrene (PHE) and zinc undecylenate (ZU) on the population growth rate (r) of the marine diatom, Skeletonema costatum. The r of S. costatum was determined after 96 hrs of exposure to PHE (0, 25, 50, 100, 200 and 300 mg L^-1) and ZU (0, 5, 10, 15, 20 and 25 mg L^-1). The results showed that r in the control (the absence of PHE and ZU) was greater than 0.04, while r in the treatment groups decreased with increasing PHE and ZU concentrations. PHE and ZU were shown to reduce r in a dose-dependent manner, with significant decreases occurring at concentrations above 50 and 10 mg L^-1, respectively. The EC₅₀ values of r in PHE and ZU exposure were 136.13 and 16.95 mg L^-1, respectively. The no observed effect concentrations (NOEC) were 25 and 5 mg L^-1, and the lowest observed effect concentrations (LOEC) were 50 and 10 mg L^-1. These results indicated that concentrations of greater than 50 mg L^-1 of PHE and 10 mg L^-1 of ZU in marine ecosystems induced a toxic effect on the r of S. costatum. These results can serve as useful baseline data for the establishment of safety concentrations of PHE and ZU in marine ecosystems.

• Korean Journal of Clinical Pharmacy
• /
• v.22 no.2
• /
• pp.176-180
• /
• 2012

The stability of triamcinolone in three kinds of oral liquid syrups at 4 and $25^{\circ}C$ was studied for 21 days. Twenty tablets of 4 mg triamcinolone were mixed with 100 mL of each oral liquid syrup, which is Levotuss$^{(R)}$Syrup (levodropropizine 6 mg/mL), Ucerax$^{(R)}$Syrup (hydroxyzine 2 mg/mL), and Xyzal$^{(R)}$Liquid (levocetirizine 0.5 mg/mL). The chromatographic analysis after deliberate degradation showed no evidence of any breakdown product likely to interfere with the chromatographic peak of the parent substance. The relationship between triamcinolone concentrations and peak areas was linear from 50 to 1000 ${\mu}g/mL$ ($r^2$ = 0.9998). The analysis method was precise, with coefficients of variation no greater than 5.4%. Triamcinolone was stable for up to 14 and 21 days in Levotuss$^{(R)}$Syrup at 25 and $4^{\circ}C$, respectively; in Ucerax$^{(R)}$Syrup and Xyzal$^{(R)}$Syrup, it was stable for at least 21 days at both temperatures. The percentages of initial triamcinolone concentration remaining after 21 days were $72.3{\pm}3.2$ and $94.9{\pm}6.0%$ and $93.2{\pm}4.9$ and $92.4{\pm}5.7%$, and $92.6{\pm}1.2$ and $92.7{\pm}2.2%$ in Levotuss$^{(R)}$Syrup, Ucerax$^{(R)}$Syrup, and Xyzal$^{(R)}$Syrup at 25 and $4^{\circ}C$, respectively. The pH variations of all test solutions were within 0.8. Based on the results, it was concluded that triamcinolone in three oral liquid syrups which are Levotuss$^{(R)}$syrup, Ucerax$^{(R)}$syrup and Xyzal$^{(R)}$syrup was chemically and physically stable in both states of refrigeration and room temperature for at least 14 days.

• YAKHAK HOEJI
• /
• v.49 no.6
• /
• pp.443-448
• /
• 2005

Diosgenin (25 (R) - spirost-5-en-3$\beta$ -ol) was oxidized with 2,3-dichloro -5,6-dicyano-1,4-benzoquinone to form 25(R)-1,4,6-spirostatrien-3-one (1) as rigid cyclic $\alpha$,$\beta$-unsaturated carbonyl compound. This compound was reacted with $H_{2}O_{2}$, m-chloroperoxybenzoic acid (mCPBA), NaOCl in the presence with (R,R)- or (S,S)-Jacobsen catalyst, tert-butyl-hydroperoxide (TBHP) in Mo$(CO)_{6}$, and in VO $(acac)_{2}$ catalyst, respectively, 25(R) -1,4,6-spirostatrien -3-one (1) was reduced with $NaBH_{4}$ L-Selectride, $LiAIH_{4}$,$BH_{3}$ $\cdot$$(CH_{3})_{2}S$, Superhydride, Red-Al, and lithium tri-tert-butoxyaluminium hydride. And 25(R)-4,6-spirostadien-3$\beta$-ol (4) was treated with $H_{2}O_{2}$, mCPBA, TBHP in D - (-) - and L-(+)-diisopropyltar-trate and $Ti(OiPr)_{4}$ condition (Sharpless asymmetric epoxidation), TBHP in $Mo(CO)_{6}$, and in $VO(acac)_{2}$ catalyst, respectively.