• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.24 no.1
• /
• pp.52-58
• /
• 2014

Objectives: Using laborers participating in the petrochemical factory turnaround process as subjects, this study aims to identify exposure to benzene in the air and examine the relationship between exposure and the excretion of urinary metabolites by measuring concentrations of urinary trans, trans-muconic acid (t,t-MA). Methods: A passive sampler was used to measure the level of benzene in the air. In order to analyze urinary metabolites, the urine of laborers participating in the turnaround process was collected twice daily, both before and after work. In addition, a survey was conducted on work factors and lifestyle habits as factors affecting the concentration of urinary metabolites. Results: During the survey period, benzene was detected in the samples from all workers, and its average concentration was $0.16{\pm}0.22ppm$. The average concentration of t,t-MA after work was $1.20{\pm}1.86mg/g$ creatinine, and the results of analyzing urinary metabolites concentration before and after work showed statistically significant differences(p=0.003). There was also a statistically significant correlation (r=0.52, p=0.002) between benzene in the air and the concentration of after-work urinary t,t-MA. Conclusions: During the turnaround process, the average benzene concentration in workers was $0.16{\pm}0.22ppm$, which was below the exposure limit. However, their average t,t-MA concentration was $1.20{\pm}1.86mg/g$ creatinine, which exceeded the exposure limit of 1mg/g creatinine. The characteristics of turnaround process work require considerations such as underestimating the passive sampler being used and the skin absorption of benzene, and there needs to be a simultaneous assessment of working environment measurements and biological monitoring.

• Economic and Environmental Geology
• /
• v.32 no.2
• /
• pp.141-150
• /
• 1999

The granitic rocks are distributed in the northeastern Gyeongsang basin, and are subdivided into the Youngduk, Younghae, Jangsadong and Onjeong granite. Based on the chondrite normalized patterns of REE by primitive mantle, the Jangsadong granite is more negative Eu anomaly than other granites. On the patterns of trace and rare earcth elements normalized by primitive mantle, Sr, P, Nd, Sm and Ti contents of t도 Youngduk and Younghae granites are higher than those of Jangsadong and Onjeong granites. Based on K-Ar ages, the Youngduk granite is 166.5 Ma for biotite, Younghae granite is 158.7 to 178.0 Ma for hornblende, Jangsadong granite is 113.8 to 118.4 Ma for K-feldspar and hornblende, and Onjeong granite is 67.4 Ma for biotite. Thus, geochemical and geochronological results suggest two plutonic episodes :the Youngduk-Younghae granites and Jangsadong-Onjeong granites suggest two plutonic episodes : the Youngduk-Younghae granites and Jangsadong-Onjeong granites. Jurassic plutonism cooled faster than Cretacous plutonism in the study area.

• Journal of The Korean Astronomical Society
• /
• v.34 no.4
• /
• pp.321-323
• /
• 2001

Compressible, magnetohydrodynamic (MHD) turbulence in two dimension is studied through high-resolution, numerical simulations with the isothermal equation of state. First, hydrodynamic turbulence with Mach number $(M)_{rms}\;\~$1 is generated by enforcing a random force. Next, initial, uniform magnetic field of various strengths with Alfvenic Mach number Ma $\gg$ 1 is added. Then, the simulations are followed until MHD turbulence is fully developed. Such turbulence is expected to exist in a variety of astrophysical environments including clusters of galaxies. Although no dissipation is included explicitly in our simulations, truncation errors produce dissipation which induces numerical resistivity. It mimics a hyper-resistivity in our second-order accurate code. After saturation, the resulting flows are categorized as SF (strong field), WF (weak field), and VWF (very weak field) classes respectively, depending on the average magnetic field strength described with Alfvenic Mach number, $(Ma)_{rms}{\ge}1$, $(Ma)_{rms}{\~}1$, and $(Ma)_{rms}{\gg}1$. The characteristics of each class are discussed.

• Journal of the Korean institute of surface engineering
• /
• v.27 no.4
• /
• pp.215-222
• /
• 1994

The role dispersoids has been studied in a number of researches as a key point for the high strength application of dispersion strengthened aluminum alloy. The mechanical alloying(MA) process with high mechanical properties of dispersion strengthened MA Al-8Ti-1B alloys were invested in order to evaluate their stress corrosion cracking(SCC) application. SCC properties of the mechanically alloyed Al-8Ti-1B were studied using slow strain rate test(SSRT). In this study Al-8Ti-1B alloy were more susceptible to SCC in solutions of pH=2.01 and 13.2 than pH=6.81 solution. In this study Al-8Ti-1B alloys by MA had more SCC resistance than Al-8Ti alloys or Al 7075-T73 alloys. So Al-8Ti-1B alloys by MA had more resistance in SSRT SCC susceptinility test than any other above alloying metals.

• Biomolecules & Therapeutics
• /
• v.32 no.2
• /
• pp.231-239
• /
• 2024

Methyl anthranilate (MA) is a botanical fragrance used in food flavoring with unexplored potential in anti-pigment cosmetics. MA dose-dependently reduced melanin content without affecting cell viability, inhibited dendrite elongation and melanosome transfer in the co-culture system of human melanoma cells (MNT-1) and human keratinocyte cell line (HaCaT), and downregulated melanogenic genes, including tyrosinase, tyrosinase-related protein 1 and 2 (TRP-1, TRP-2). Additionally, MA decreased cyclic adenosine monophosphate (cAMP) production and exhibited a significant anti-pigmentary effect in Melanoderm^TM. These results suggest that MA is a promising anti-pigmentary agent for replacing or complementing existing anti-pigmentary cosmetics.

• Journal of applied mathematics & informatics
• /
• v.25 no.1_2
• /
• pp.329-337
• /
• 2007

In the paper, we obtain the existence of positive solutions and establish a corresponding iterative scheme for BVPs $$\{^{\;(\phi_p(u'))'\;+\;q(t)f(t,u)=0,\;0\;<\;t\;<\;1,}_{\;u(0)\;-\;B(u'({\eta}))\;=\;0,\;u'(1)\;=\;0}$$ and $$\{^{\;(\phi_p(u'))'\;+\;q(t)f(t,u)=0,\;0\;<\;t\;<\;1,}_{\;u'(0)\;=\;0,\;u(1)+B(u'(\eta))\;=\;0.}$$. The main tool is the monotone iterative technique. Here, the coefficient q(t) may be singular at t = 0, 1.

• Journal of Digital Convergence
• /
• v.16 no.2
• /
• pp.47-56
• /
• 2018

The purpose of this study was to identify the relation among the CRR, MA, and MS of military solder's who have experienced couple relationship troubles. Data collected from 239 soldiers in front-line division and post line division was analyzed by correlation analysis, t-test and hierarchical analysis using SPSS 18.0. As the results, 1. CRR and MA showed a positive correlation and CRR and MS showed a negative corelation. 2. CRR showed a significant influence on the MA. 3. CRR had a mediating effects on the process where MS influenced MA. The results of this study are expected to be used as the primary data for raising the adaptability to the military especially on the subject of couple relationship, and as an educational guidance for helping soldiers to see the positive aspect of the adversity and stress of military life.

• YAKHAK HOEJI
• /
• v.59 no.3
• /
• pp.92-97
• /
• 2015

KIOM-MA128 is a novel Korean herbal medicine with anti-atopic, anti-inflammatory and anti-asthmatic effects. This article presents the first pharmacokinetic study on KIOM-MA128. The purpose of this study was to characterize a pharmacokinetic characteristic of matrine, a potential marker of KIOM-MA128, in rats using population pharmacokinetic model. 1, 2 and 8 g/kg of KIOM-MA128 were administered to rats orally and plasma concentrations of matrine was determined by HPLC-MS/MS. Non-compartmental analysis (NCA) was performed using Phoenix$^{(R)}$ and pharmacokinetic model was built using NONMEM$^{(R)}$. This model was validated with internal validation which is visual predictive check (VPC) and bootstrap. The NCA result of matrine showed that $C_{max}$ was 294.24, 552.22 and 868.65 ng/ml, $AUC_{inf}$ was 1273.05, 2724.76 and $9743.25ng{\cdot}hr/ml$ and $T_{max}$ was 1, 1.3 and 2.3 hr for the doses of 1, 2, and 8 g/kg, respectively. The rat plasma concentrations were described very well with one-compartment model. Pharmacokinetic model for matrine was successfully developed and evaluated. Finally, our model is helpful to understand pharmacokinetic characteristic of KIOM-MA128.

• Journal of Adhesion and Interface
• /
• v.11 no.3
• /
• pp.106-111
• /
• 2010

Na-MMT intercalated with PEGMA macromer was prepared using an EtAc/acetone mixture (1/1 by volume) as a solvent. PEGMA/(Na-MMT)-co-MMA/MA nanocomposites was synthesized by copolymerizing intercalated compound with MMA and MA, and then characterization was performed. The results of X-ray diffraction (XRD) showed that in the case of Na-MMT intercalated with PEGMA macromer the d-spacings of silicate of Na-MMT increased with increasing of Na-MMT loading. As the Na-MMT loading increases Tg showed increasing trend through the DSC measurement. TGA result showed that thermal stability of PEGMA/(Na-MMT)-co-MMA/MA nanocomposites improved a little more than the pure PEGMA-co-MMA/MA.

• Food Science and Preservation
• /
• v.5 no.2
• /
• pp.105-110
• /
• 1998

To find out suitable storage and marketing condition, northern type 'seosan' garlic was stored for 3 months at controlled atmosphere(CA), modified atmosphere(MA), low(0~1$^{\circ}C$) and room temperature(20$\pm$5$^{\circ}C$), and then marketed at low(2~3$^{\circ}C$) and room temperature (20$\pm$5$^{\circ}C$)after storage. The physiological properties of garlic were investigated among treatments. The garlic respiration increased after 2 months at room temperature storage, which seem to be dormancy break time. During storage of garlic by CA, MA condition, sprouting and weight loss were prevented effectively by suppress of respiration, and hardness was maintained higher then those of the others. Decay rate occurred 8.1% at room temperature storage, 2% at MA storage but didn't occurred at CA and low temperature storages. When marketed at room and low temperature after storage, increment of respiration and sprouting were delayed, and changes of weight and hardness were low in garlics stored at CA and MA. Decay rate occurred high in garlics stored at MA and room temperature.