• Journal of Korean Society for Atmospheric Environment
• /
• v.7 no.2
• /
• pp.119-126
• /
• 1991

Air pollution is directly and indirectly associated with the toxicology through the increase of mortality, the decrease of oviposition rate, and the decline of insect population, as well as the disruption of equilibria with higher or lower trophic levels. To investigate intrinsic decrease rates, oviposition period, and emerging rates of pupae of house fly under air pollution stresses, healthy individuals of Musca domestica L. were collected in the field, cultured in the laboratory for 2 $\sim$ 3 generations, and artificially exposed to $O_3 (4 ppm) in automatically controlled air pollutant fumigation chambers. Results from this study are summarized as follows: 1. Survivorship curves of both control group and exposed groups of healthy house fly to 4 ppm $O_3$ have linearly or stair-like decreasing trends of revers S-shape. 2. For cohorts exposed to 4 ppm of $O_3$, intrinsic decrease rate of cohort exposed for 2 hours significantly increases compared to that of control group, slight increases were observed for those exposed for 4 hours and 8 hours, which shows no distinct relationships between exposure period and intrinsic decrease rate. 3. While the numbers of pupae of exposed cohorts increase with the increase of exposure period, emerging rate shows a distinct decrease. 4. The relationships between emerging rate (E) of pupae and the exposure period (T) for cohorts exposed to 4 ppm of $O_3$ are expressed with the equation, E (%)=21.027 - 7.942 ln (T).

• Animal cells and systems
• /
• v.6 no.1
• /
• pp.19-22
• /
• 2002

Life table studies were conducted in the laboratory for the eulophid gregarious pupal parasitoid, Tetrastichus sp., on Hyphantria cunea Drury at a constant temperature of 28.2$\pm$2$^{\circ}C$, 50-60% RH to evaluate their impact on the host and their potential biological control. Development of immature stage took 20.1$\pm$2.7 d: adult females lived for 23.2$\pm$2.2 (range, 16-27)d and produced a mean of 53.6$\pm$26.6 adult progeny per female, with a sex ratio of 1: 9.5 (M:F). The intrinsic rate of natural increase (r$_{m}$) was 0.178/ female/day; the net reproductive rate (R$_{o}$), 46.74; the capacity for increase (r$_{c}$) 0.177; the finite rate of increase (λ) 1.19/female/day; thus each female contributed 46.74 individuals to the population in a mean generation time of 21.6 d. Biological factors in determining the life history trait variation of the parasitoid were discussed.d.d.d.

• Korea journal of population studies
• /
• v.4 no.1
• /
• pp.5-13
• /
• 1981

• Korean journal of food and cookery science
• /
• v.4 no.1
• /
• pp.17-26
• /
• 1988

The polysaccharide produced by pseudomonas elodea, Gellan gum, was rheologically characterized, compared with agar. Rheological properties were determined from the change in the value of intrinsic viscosity with the pH and salt concentration. At the range of pH 2∼ll and salt 0∼0.16M KC1, the intrinsic viscosity of Gellan gum ranged from 8.8 to 21.2dl/g and agar ranged from 1.97 to 11.46d1/g. In the absence of salt, the intrinsic viscosity of Gellan gum increased as the pH of solution increased up to neutral pH then decreased slightly at alkaline pH, whearas the intrinsic viscosity of agar increased as the pH of solution increased up to pH 9 then decreased slightly. Intrinsic viscosity of Gellan gum and agar decreased with an increase in salt concentration. The chain stiffness parameter for the Gellan gum was 0.033. The overlap parameter of Gellan gum and agar were 0.047g/dl and 0.087g/dl, respectively. Gellan gum and agar were shear rate dependent or pseudoplastic. The yield stress and proportionality constant of Gellan gum increased slightly as the concentration increase, on the other hand, the shear index of Gellan gum showed a maximum at 0.75g/dl and gradually decreased as the concentration increase. The apparent viscosity of Gellan gum and agar decreased as the temperature increase. A lower concentration of the divalent cations calcium and magnesium is required to obtain maximum gel strength than for the monovalent cations sodium and potassium.

• Transactions of the Korean hydrogen and new energy society
• /
• v.1 no.1
• /
• pp.1-8
• /
• 1989

The hydriding kinetic mechanism and the change of the hydriding reaction rate of $MmNi_{4.5}Al_{0.5}$ during the thermally induced hydrogen absorption-desorption cycling are investigated. Comparison of the reaction rate data which are obtained by the pressure sweep method with the theoretical rate equations suggests that the hydriding rate controlling step has changed from the dissociative chemisorption of hydrogen molecules at the surface to the hydrogen diffusion through the hydride phase with the increase of the hydriding fraction. These hydriding kinetic mechanism is not changed during the cycling. However, the intrinsic hydriding reaction rate of $MmNi_{4.5}Al_{0.5}$ after 5500 cycles increases significantly comparing with the activated one. It is suggested that the change of the hydriding kinetic behavior due to intrinsic degradation of $MmNi_{4.5}Al_{0.5}$ can be interpreted as follows ; the formation of nickel cluster at the surface of the sample and the host metal atom exchange in bulk by thermal cycling.

• International Journal of Internet, Broadcasting and Communication
• /
• v.12 no.3
• /
• pp.226-232
• /
• 2020

Repetition of landing with visual control in sports and training is common, yet it remains unknown how landing with visual control affects postural stability and lower limb kinetics. The purpose of this study was to test the hypothesis that landing with visual control will influence on lower limb control for intrinsic dynamic postural stability. Kinematics and kinetics variables were recorded automatically when all participants (n=10, mean age: 22.00±1.63 years, mean heights: 177.27±5.45 cm, mean mass: 73.36±2.80 kg) performed drop landings from 30 cm platform. Visual control showed higher medial-lateral force, peak vertical force, loading rate than visual information condition. This was resulted from more stiff leg and less time to peak vertical force in visual control condition. Leg stiffness may decrease due to increase of perturbation of vertical center of gravity, but landing strategy that decreases impulse force was shifted in visual control condition during drop landing. These mechanism explains why rate of injury increase.

• Korean journal of applied entomology
• /
• v.40 no.2
• /
• pp.111-115
• /
• 2001

Orius strigicollis Poppies is an indigenous natural enemy of thrips pests in Korea To develop an efficient mass rearing system for Ο. strigicollis, effects of hatchability, egg numbers and egg harvesting time of Ο. strigicollis were measured in cylindrical cage (251 ㎤) under the conditions of photoperiod 16L : 8D, $55\pm$10% RH and $25\pm$$2^{\circ}C$. The hatchability and developmental period of eggs were 88.5% and 5.7 days, respectively. The highest emergence rate (50.8%) was achieved when the number of eggs laid was ranged from 50 to 100 per arena. The proper harvesting time of newly produced adults was 17 days postoviposition. Relationship between the number of resulting adults per female and the number of female adults per arena was Y : -10.7971n (X) +44.659 ($R^2$=0.7619). The generation time (T), the net reproductive rate ($R_{0}$ ) and the intrinsic rate of natural increase ($r_{m}$ ) were 26.5 days, 6.18 and 0.0687, respectively.

• Korean journal of applied entomology
• /
• v.41 no.2
• /
• pp.85-89
• /
• 2002

Development and reproduction of the rice armyworm, Pseudaletia separara, were investigated on different diets (corn leaf, rice leaf, Chinese cabbage leaf, cabbage leaf, sweetpotato leaf, soybean leaf and silkworm artificial diet). Egg and pupal periods were not different among the diets. But larval periods showed significant difference among diets. Developmental period from egg to adult was shortest as 32.5 d on corn leaf and longest as 46.6 d on soybean leaf. At 16 days after hatching, larval weights on rice and silkworm artificial diet were heavier than those on other diets. The larvae reared on cabbage leaf and sweetpotato leaf failed to pupate. Survival rates from larva to adult were highest (70.6%) on com leaf lowest (39.8%) on soybean leaf. The longevity of female adults was not affected by the larval diets. Female adults showed higher fecundity when the larvae were fed with corn leaf, rice leaf and silkworm artificial diet than other diets. Net reproduction rate (R$_{0}$) was highest as 1218.5 on silkworm artificial diet. The intrinsic rate of natural increase (R$_{0}$) ranged from 0.115 to 0.175, and was maximum on com leaf.

• Journal of Pharmaceutical Investigation
• /
• v.22 no.3
• /
• pp.219-227
• /
• 1992

The influence of phenobarbital (PB) pretreatment (75 mg/kg/day, i.p. for 4 days) on the pharmacokinetics of diltiazem (DTZ) and its metabolite, desacetyldiltiazem (DAD), was investigated in rats. DTZ was injected via femoral (3 mg/kg) or portal (10 mg/kg) vein to the control and PB-pretreated rats. DAD was also injected separately via femoral (3 mg/kg) vein to both groups of rats. The intrinsic hepatic plasma clearance of DTZ was found to be significantly increased (6.8-fold) by the PB pretreatment. However, the fraction of an intravenous DTZ dose converted to DAD $(F_mi)$ was only slightly (6%) increased and calculated metabolic rate constant of DTZ to DAD was not affected by the pretreatment. On the other hand, plasma free fraction of DTZ was increased (1.8-fold) from $4.24{\pm}0.25%$ to $7.45{\pm}0.54%$ by the pretreatment. However, the l.8-fold increase in the free fraction of DTZ would not explain the 6.8-fold increase in the hepatic intrinsic clearance of DTZ. Therefore, the increase in either the hepatic blood flow or the metabolism other than to DAD was expected as the probable mechanism(s) of the increased hepatic clearance of DTZ. Sequential metabolism of DAD to further metabolites, however, would be a more potential cause of the apparently unchanged metabolism of DTZ to DAD by the PB-pretreatment.

• The Korean Journal of Physiology and Pharmacology
• /
• v.6 no.6
• /
• pp.287-291
• /
• 2002

Intrinsic excitabilities of acutely isolated medial vestibular nucleus (MVN) neurons of rats with normal labyrinth and with undergoing vestibular compensation from 30 min to 24 h after unilateral vestibular deafferentation (UVD) were compared. In control rats, proportions of type A and B cells were 30 and 70%, respectively, however, the proportion of type A cells increased following UVD. Bursting discharge and irregular firing patterns were recorded from 2 to 12 h post UVD. The spontaneous discharge rate of neurons in the ipsilesional MVN increased significantly at 2 h post-UVD and remained high until 12 h post-UVD in both type A and type B cells. After-hyperpolarization (AHP) of the MVN neurons decreased significantly from 2 h post-UVD in both types of cells. These results suggest that the early stage of vestibular compensation after peripheral neurectomy is associated with an increase in intrinsic excitability due to reduction of AHP in MVN neurons.