• IE interfaces
• /
• v.16 no.2
• /
• pp.149-155
• /
• 2003

The focus of this study is to investigate how personal display systems - a VDU (Visual Display Unit) and an HMD (Head Mounted Display) physiologically affect the body in virtual environments, and to evaluate differential effects of using the VDU and the HMD on physiological responses to mental stressful tasks (virtual reality flight simulation). As physiological variables, autonomic measures (heart rate, blood pressure), immune cells (leukocyte, neutrophil, lymphocyte), and hormones (catecholamine) were measured before and after experiments. Physiological data were measured in order to compare a level of mental stress on the VDU and the HMD. Increments in blood pressure (systolic (p<0.05), diastolic (p<0.1)), norepinephrin (catecholamine) (p<0.005), and neutrophils (p<0.2) of the group using the HMD showed a significant difference with the group using the VDU. Although, the heart rate was not statistically significant between two environments, differences of them quietly increased on the HMD more than on the VDU.

• Journal of Microbiology and Biotechnology
• /
• v.7 no.6
• /
• pp.378-385
• /
• 1997

Cation motive ATPases on cell membranes of Helicobacter pylori were investigated using everted membrane vesicles. Latent ATPases could be ascertained from aggregated vesicle using N, N-dimethylformamide (DMF) and Triton X-100. By contrast, ultrasonication or chloroform treatments caused membranes to be disrupted, resulting in an alteration of sensitivities against azide or vanadate. Considerable amounts of vanadate-sensitive enzymes were identified from vesicle micelles, prepared by the dilution method. These were activated in the presence of either $Ni^{2+}\;or\;NH_4^+$. From studies employing H. pylori intact cell systems, we found that ATPase expression of this bacterium was markedly dependent upon air composition. It was interesting that cellular expression of $Ni^{2+}$- or $NH_4^{+}$-motive ATPases was significantly affected by extracellular pH, suggesting that these unique enzymes may physiologically be involved in cellular $Ni^2$ import and $NH_4^+$ export, respectively.

• Microbiology and Biotechnology Letters
• /
• v.25 no.4
• /
• pp.379-385
• /
• 1997

Several protease-deficient mutants of Aspergillus niger have been isolated by halo-screening on skim milk plate after UV irradiation of conidiospores. The extracellular proteolytic activities of the mutant strains grown in an optimized medium varied from 3% to 85% of that of the parental strain. Especially, two mutant strains named as ANPD-129 and ANPD-153, which had 3% and 49% of acid protease activity of the parental strain, respectively, were further characterized both physiologically and genetically. The growth rates of the mutants, ANPD-129 and ANPD-153, were similar to that of the parental strain, unlike other protease-deficient mutants. The diploid formed between the two mutants restored protease activity to a similar level of that of the parental strain. This result revealed that ANPD-129 and ANPD-153 had mutations at different loci. Using master strains with marked chromosomes these loci were assigned to linkage groups. The mutation locus (prt129) in ANPD-129 was assigned to linkage group VI and the locus (prt153) in ANPD-153 to linkage group III.

• Proceedings of the PSK Conference
• /
• 2003.04a
• /
• pp.235.3-236
• /
• 2003

S-adenosyl-L-homocysteine(AdoHcy) is the product of all biological methylation in which S-adenosyl-L-methionine (AdoMet) is utilized as a methyl donor and is reversibly hydrolyzed to L-homocysteine and adenosine by AdoHcy hydrolase physiologically. Inhibition of this enzyme results in intracelluar accumulation of AdoHcy leading to a feedback inhibition of AdoMet-dependent methylation reactions which are essential for viral replication. (omitted)

• Journal of the Ergonomics Society of Korea
• /
• v.17 no.1
• /
• pp.79-89
• /
• 1998

This study describes the research contents, strategies, and applications of simulator for measuring and evaluating human sensibility. The simulator is the integrated experiment facility which can change the physical environment artificially to measure and grasp the reaction feature of human sensibility for the products and environments. The design technique consists of two parts; development of technique to present the mock environment related to sensibility elements and development of software to measure and evaluate sensibility physiologically and psychologically. The simulator can be utilized for evaluating the main industrial products and environments. Therefore, the simulator can increase the added-value of the product and environment, and also contribute to the improvement of quality of human life.

• YAKHAK HOEJI
• /
• v.59 no.4
• /
• pp.151-157
• /
• 2015

The purpose of this study is to demonstrate how lead compounds are best optimized with the application of in silico QSAR and PBPK modeling at the early drug discovery stage. Several predictive QSAR models such as $IC_{50}$ potency model, intrinsic clearance model and brain penetration model were built and applied to a set of virtually synthesized library of the BACE1 inhibitors. Selected candidate compounds were also applied to the PBPK modeling for comparison between the predicted animal pharmacokinetic parameters and the observed ones in vivo. This novel lead optimization strategy using QSAR and PBPK modelings could be helpful to expedite the drug discovery process.

• Journal of Plant Biology
• /
• v.35 no.2
• /
• pp.173-182
• /
• 1992

The parasitic flowering plants obtain nutrients and water from their host plants through a parasitic organ, haustorium, which connects both structurally and physiologically host and parasite. The parasitism in angiosperms thus can be understood from the knowledge of the haustorial structure. The haustoria have evolve convergently and independently in several unrelated taxa; therefore, they have similar morphology. Many anatomical studies on the haustoria in several parasites in the pst have been carried out by light microscopy. Ultrastructural studies on the haustoria, which are started from the end of 1060s', have provided new information relating to the phenomenon of parasitism in angiosperms. The purpose of this paper is to introduce and compare the structure of haustoria between parasitic plants. The results may help an understanding of phylogenetic relationships of parasitic angiosperms. The haustoria of some families, such as Santalaceae, Orobancaceae, Scrophulariaceae, Loranthaceae (or Viscaceae), and Convolvulaceae (Cuscuta) will be discussed.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.3 no.1
• /
• pp.11-16
• /
• 2005

Chemical mixtures of components, each of which are present at less than guidance concentrations, may be hazardous due to additivity, interactions, or both. Toxicological interactions may increase the health hazard above what would be expected from an assessment of each component singly, or all components additively. So chemical mixture are a particular issue in public health. There are several approach to assess whether there are additivity or interaction in assessing toxicological effects, such as, components-based approach, physiologically-based pharmacokinetic /pharmacodynamic(PBPK/PD) models, hazard index method, and weight-of evidence method. If we consider interaction or additivity effects in assessing the health effects of chemcial mixtures, we can get more accurate information about toxicological effects and dose-response relationship in chemical mixtures.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1995.10a
• /
• pp.135-136
• /
• 1995

Resent advances in computer technology have introduced a sophisticated capability for computing the biological fate of toxicants in a biological system. This methodology, which has drastically altered risk assessment skill in toxicology, is designed using all the mechanistic information, and all claim better accuracy with extrapolating capability Iron animal to people than conventional pharmacokinetic methods. Biologically based mathematical models in which the specific mechanistic steps governing tissue disposition(pharmacokinetics) and toxic action (pharmacodynamics) of chemicals are constructed in quantitative terms by a set of equations loading to prediction of the outcome of specific toxicological experiments by computer simulation. pharmacokinetic and pharmacodynamic models are useful in risk assessment because their mechanistic biological basis permits the high-to-low dose, route to route and interspecies extrapolation of the tissue disposition and toxic action of chemicals.

• Journal of Preventive Medicine and Public Health
• /
• v.20 no.2 s.22
• /
• pp.215-220
• /
• 1987

Under the extreme change of the environment, animals react physiologically to adapt to the stress and secrete catecholamines. Cold exposure is a kind of the environmental stress. Author tried to determine the amount of catecholamines in rat urine as a parameter of physiological response to cold stress. Urinary catecholamine was measured by using HPLC with fluorescence detector, cation exchange column prepacked with Bio·Rex 70 and ammonium pentaborate as catecholamine eluent. The amount of dopaminc in normal state rat urine was 42.0 ng, but under the low temperature of $5^{\circ}C$, the dopamine amount was increased to 221.25 ng/5 ml. Above findings are suggesting that catecholamine secretion, especially dopamine, increases in the stressful condition such as cold exposure.