• Asian Journal of Atmospheric Environment
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• v.12 no.1
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• pp.17-29
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• 2018

For the first time in the city of Riyadh, the formation of $O_3$ and its relationship with NO and $NO_2$ ($NO_x$) was investigated. Throughout the summer $O_3$, NO, and $NO_2$ were collected from three locations: residential, industrial, and rural areas. During the sampling period $O_3$ concentrations exceeded 1-hour local standards a few times yet remained consistent with the standards most of the time. The $O_3$ concentrations were observed highest in the rural location and lowest in the industrial area. The diurnal variation of NO followed a double peak: one in the morning and the other in the evening, representing the traffic pattern. Early morning NO peaks were observed in the rural location, which were attributed to the movement of NO from other locations. The $O_3$ concentrations depicted typical pattern, increasing after sunrise and reaching its maximum during midday. The highest $O_3$ concentrations were observed in the rural location followed by the residential and industrial. $NO_2$ photolysis rates were 3-4 times higher compared to other similar investigations, potentially due to intense solar radiation. A strong negative correlation was observed between $NO_x$ and $O_3$ values in the industrial location indicating photochemical activities around the industrial area were higher, likely due to additional $NO_x$ emissions from industries. Regression analysis of $NO_x$ and OX ($O_3+NO_2$) indicated that in residential and industrial locations at nighttime there were large $NO_x$ independent regional contributions which is attributed to VOCs. The Weekend Effect was observed in the city potentially due to the production of the OH radical and subsequent reactions with VOCs implying that the area is VOC-sensitive.

• Archives of Plastic Surgery
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• v.35 no.2
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• pp.121-126
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• 2008

Purpose: Poly-N-acetyl glucosamine(PGlcNAc) nanofiber-based materials, produced by a marine microalga, have been characterized as effective hemostatic and angiogenic agents. The similarity between PGlcNAc patch and the natural extracellular matrix allows it to support new healthy tissue growth in an injured area and to encourage fluid absorption. In this study, we hypothesized that a poly-N-acetyl glucosamine fiber patch(PGlcNAc patch) may enhance wound healing in the db/db mouse. Methods: PGlcNAc patches were applied on one square centimeter, full-thickness, skin wounds in the db/db mouse model. Wounds(n=15 per group) were dressed with a PGlcNAc nanofiber patch for 1 hour(1 h), 24 hours(24 h) or left untreated(NT). After the application time, patches were removed and wounds were allowed to heal spontaneously. The rate of wound closure was evaluated by digital analysis of unclosed wound area in course of time. At day 10, wounds(n=7 per group) were harvested and quantified with immunohistochemical markers of proliferation(Ki-67) and vascularization (platelet endothelial cell adhesion molecule, PECAM-1). Results: Wounds dressed with PGlcNAc patches for 1 hour closed faster than control wounds, reaching 90% closure in 16.6 days, nine days faster than untreated wounds. Granulation tissue showed higher levels of proliferation and vascularization following 1 h treatment than the 24 h and NT groups. In addition to its hemostatic properties, the PGlcNAc material also appears to accelerate wound closure in healing-impaired genetically diabetic mice. Conclusion: This material, with its combination of hemostatic and wound healing properties, has the potential to be effective agent for the treatment of complicated wounds.

• Korean Journal of Food Science and Technology
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• v.21 no.3
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• pp.331-337
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• 1989

In order to investigate the method for extension of shelf-life of Kimchi, the effect of low temperature heating and addition of mustard oil on pH and total acidity of Kimchi during storage at $15^{\circ}C$ were studied. Mustard oil was found to have the antimicrobial effect on the major lactic acid bacteria of Kimchi such as Lactobacillus plantarum, Lactobacillus brevis, Leuconostoc mesenteroides and Pediococcus cerevisiae, Addition of 200p.p.m. mustard oil, 0.1% mustard powder and 0.01% $H_2O_2$ to Kimchi effectively reduced the fermentation rate of Kimchi. Low temperature heating of salted cabbage and addition of 200p·p.m. mustard oil and 0.01% $H_2O_2$ to seasonings extented the time reaching optimum ripening of Kimchi about 2.5 times longer than control. Combination of low temperature heating, addition of mustard oil and $H_2O_2$ to seasonings and post low temperature heating delayed fermentation time Kimchi about 5 times longer than control after 15 days storage at $15^{\circ}C$.

• Physical Therapy Rehabilitation Science
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• v.9 no.3
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• pp.155-164
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• 2020

Objective: This study aimed to compare muscle structure, balance, and gait parameters between healthy adults and persons with stroke and to analyze the correlation among these variables. Design: Cross-sectional study. Methods: Twenty persons with stroke (11 male, 9 female) and twenty healthy participants (9 male, 11 female) were included. Ultrasound images of the triceps surae and the tibialis anterior were acquired in sitting resting, sitting co-contraction, and standing resting positions and also during the functional reach test (FRT) and single leg anterior reaching test (SLART). Muscle thickness and fascicle length were measured. Spatiotemporal parameters of gait were measured using a pressure walkway. Gait speed, cadence, step length, stride length, stance time, and swing time were measured. Results: Changes in percent fascicle length were significantly greater in the gastrocnemius and soleus (SOL) muscles of healthy adults in the sitting co-contraction position (p<0.05). The percent fascicle length of the SOL in FRT and SLART were significantly greater in healthy adults (p<0.05). The mid-stance phase of stroke patients was shorter than healthy adults (p<0.05). A negative correlation was observed between percent fascicle length of the SOL in the sitting co-contraction position and the proportion of the mid-stance phase (p<0.05). Conclusions: The function of the triceps surae is affected in persons with stroke when compared with healthy adults. This can lead to difficulty in performing tasks that involve forward transfer of weight. If the triceps surae is not sufficiently secured, the possibility of compensation in the stance phase increases during gait.

• Journal of Pharmaceutical Investigation
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• v.24 no.3
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• pp.155-165
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• 1994

Some mucoadhesive polymers such as hydroxypropylcelluose (HPC) and carbopol-934 (CP) have been employed for the preparation of mucoadhesive polymeric systems, and their physical properties including mucoadhesion, swelling, and drug release were evaluated. A new simple experimental technique that can quantitatively measure the bioadhesive properties of various polymeric systems has been developed by the methods of detachment force test. As the polymeric systems, the discs of freeze-dried HPC/CP solid dispersions were prepared. The mucosa used in these tests were upper, middle, and lower parts of small intestine of male rats weighing $300{\sim}350\;g$. Detachment forces were increased as the mole fraction of CP increased in discs of HPC/CP solid dispersions. In the points of intestinal site dependence of mucoadhesion, the solid dispersions revealed non-specific mucoadhesion to the intestine. Swelling and drug release characteristics of mucoadhesive polymeric systems were studied extensively to find out the feasibility for the oral controlled delivery systems. Swelling ratio, expressed as the final height/initial height, has been determined in various pH buffer solutions. Hydrochlorothiazide (HCT) was employed as a model drug for release study. Apparent swelling and drug release rate constants, $K_s$ and $K_r$ respectively, were obtained from the square-root time plot of either swelling ratio or released amount of drug, particularly for the time periods before reaching the equilibrium. As a result, the swelling ratio of HPC/CP solid dispersions was increased as the weight percentage of CP increased. Similarly, the release of HCT from the solid dispersions was dependent on pH changes and CP contents, resulted in the slower release of HCT with the increases of pH and CP contents.

• Journal of the Korean Ceramic Society
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• v.38 no.9
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• pp.787-793
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• 2001

$La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ membranes were fabricated by solid-state reaction. We investigated sintering behavior and oxygen permeation flux as a function of time-on-stream, temperature and upstream oxygen partial pressure. The oxygen was permeated at temperatures form 750$^{\circ}$C to 950$^{\circ}$C by mixed conducting through oxygen vacancy diffusion in the dense membrane. The oxygen permeation flux through the membrane were about 0.1ml/$cm^3{\cdot}$min at 850$^{\circ}$C. A constant time was required for reaching stable oxygen flux, and oxygen partial pressure affected the oxygen permeation fluxes.

• Physical Therapy Korea
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• v.14 no.1
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• pp.11-20
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• 2007

The objective of this study was to discern the effects of a balance training program on the performance of lower extremities in order to improve strength (muscle power, flexibility, walking power), balance control and walking ability in the elderly. The subjects selected were aged 65 years and over, with no known relevant medical history that may disturb their balance, and have also been visiting the Gimhae Senior Welfare Center. The variable group consisted of 30 subjects, of whom were people who had been participating in balance training programs (One Leg Standing; OLS, Functional Reach; FR, Timed Get Up and Go; TUG) as an intervention for 8 weeks 3 times per a week. They were examined in order to identify their balance control before and after. The control group consisted of thirty subjects who preferred to exercise without any intervention relating to balance training program. The subjects were measured before and after balance training in order to determine the effectiveness of exercise and the effectiveness of exercise combined with the aid of a Balance Performance Monitor. 1. Mean time on OLS test with left and right sided extremities in the experimental group was 35.44 sec, 42.10 sec longer than control group respectively. In FR tests applied to the left and right side, mean reaching distance was increased up to 5.56 cm, 6.73 cm in experimental group respectively. Mean time on TUG test from a chair in experimental group was decreased to 2.33 sec. 2. Mean value of decline in the level balance control, both left and right side, decreased to 2.24% as examined by the Balance Performance Monitor. Mean scores for sway level after balance training decrease to .98% and for balance control both anterior and posterior directions decreased to mean 1.07% and 1.44%, respectively.

• Special Issue of the Society of Naval Architects of Korea
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• 2011.09a
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• pp.117-126
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• 2011

The buckling assessment of plate panels described in common structural rules (CSR) is to be determined according to the buckling utilization factor with hull girder stresses calculated on net hull girder sectional properties. As the thickness requirement for the buckling assessment of plate panels is not explicitly given in CSR, a lot of time is spent to find the proper thickness of plate panels until reaching to an allowable buckling utilization factor. In this study, in order to reduce time and cost, the thickness requirement of plate panels satisfying buckling assessment was derived. The structural design system included with the thickness requirement for buckling assessment was developed. The system is called as Oil-tanker Automated Structural Investigation System (OASIS). The design result of longitudinal strength members using OASIS was verified by Nauticus Hull which is the rule scantling software of DNV. Finally, optimum design of a double hull tanker for the minimum weight using OASIS was presented.

• Journal of Ocean Engineering and Technology
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• v.27 no.2
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• pp.75-79
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• 2013

This study was carried out to investigate the precipitation behavior of the ${\chi}$ phase and the impact toughness of 25%Cr-7%Ni-2%Mo-4%W super duplex stainless steel. The ${\chi}$ phase was precipitated in the early stage of aging, and with the increasing aging time. However, after reaching a maximum value, the number decreased as a result of the gradual transformation of the ${\chi}$ phase into the ${\sigma}$-phase. It was proved that the ${\chi}$ phase was an intermetallic compound, which represented a lower nickel concentration, higher chromium and molybdenum concentrations, and very higher tungsten concentration compared to the matrix phases. It also showed higher molybdenum and tungsten concentrations than the ${\sigma}$ phase. The decomposition of the ferrite phase into the ${\gamma}_2$ and ${\sigma}$ phases was retarded by W substitution for Mo. Thus, the number of ${\chi}$ phases increased. The impact value was decreased by the substitution of W for Mo. The impact toughness rapidly decreased with time when the ${\chi}$ phase began to precipitate in the initial stage of aging. The impact toughness was, therefore, greatly influenced for the precipitation of the ${\chi}$ phase.

• Journal of Ginseng Research
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• v.39 no.4
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• pp.304-313
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• 2015

Background: Ginsenoside Rg3 is a promising anticancer agent. It is usually produced by heat treatment of ginseng, in which ginsenoside Rb1 is the major ginsenoside. A kinetic study was conducted to optimize ginsenoside Rg3 production by the heat treatment of ginsenoside Rb1. Methods: Ginsenoside Rb1 was heated using an isothermal machine at $80^{\circ}C$ and $100^{\circ}C$ and analyzed using HPLC. The kinetic parameters were calculated from the experimental results. The activation energy was estimated and used to simulate the process. The optimized parameters of ginsenoside Rg3 production are suggested based on the simulation. Results: The rate constants were $0.013h^{-1}$ and $0.073h^{-1}$ for the degradation of ginsenosides Rb1 and Rg3 at $80^{\circ}C$, respectively. The corresponding rate constants at $100^{\circ}C$ were $0.045h^{-1}$ and $0.155h^{-1}$. The estimated activation energies of degradation of ginsenosides Rb1 and Rg3 were 69.2 kJ/mol and 40.9 kJ/mol, respectively. The rate constants at different temperatures were evaluated using the estimated activation energies, and the kinetic profiles of ginsenosides Rb1 and Rg3 at each temperature were simulated based on the proposed kinetic model of consecutive reaction. The optimum strategies for producing ginsenoside Rg3 from ginsenoside Rb1 are suggested based on the simulation. With increased temperature, a high concentration of ginsenoside Rg3 is formed rapidly. However, the concentration decreases quickly after the reaching the maximal concentration value. Conclusion: The optimum temperature for producing ginsenoside Rg3 should be the highest temperature technically feasible below $180^{\circ}C$, in consideration of the cooling time. The optimum reaction time for heat treatment is 30 min.