• Journal of Microbiology and Biotechnology
• /
• v.24 no.6
• /
• pp.740-747
• /
• 2014

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice-growing regions of the world. In spite of their economic importance, there are no effective ways of protecting rice plants from this disease. Bacteriophages infecting Xoo affect the population dynamics of the pathogen and consequently the occurrence of the disease. In this study, we investigated the diversity, host range, and infectivity of Xoo phages, and their use as a bicontrol agent on BLB was tested. Among the 34 phages that were isolated from floodwater in paddy fields, 29 belonged to the Myoviridae family, which suggests that the dominant phage in the ecosystem was Myoviridae. The isolated phages were classified into two groups based on plaque size produced on the lawn of Xoo. In general, there was a negative relationship between plaque size and host range, and interestingly the phages having a narrow host range had low efficiency of infectivity. The deduced protein sequence analysis of htf genes indicated that the gene was not a determinant of host specificity. Although the difference in host range and infectivity depending on morphotype needs to be addressed, the results revealed deeper understanding of the interaction between the phages and Xoo strains in floodwater and damp soil environments. The phage mixtures reduced the occurrence of BLB when they were treated with skim milk. The results indicate that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals.

• Reproductive and Developmental Biology
• /
• v.37 no.1
• /
• pp.51-55
• /
• 2013

The present study was conducted to examine the effect of antioxidant treatment during parthenogenetic activation procedure on the reactive oxygen species (ROS) levels and in vitro development of porcine parthenogenetic embryos. Porcine in vitro matured oocytes were activated by a combination of electric stimulus and 2 mM 6-dimethylaminopurine (6-DAMP) before in vitro culture. During the activation period, oocytes were treated with $50{\mu}M$ ${\beta}$-mercaptoethanol (${\beta}$-ME), $100{\mu}M$ L-ascorbic acid (Vit. C) or $100{\mu}M$ L-glutathione (GSH). To examine the ROS level, porcine parthenogenetic embryos were stained in $10{\mu}M$ dichlorohydrofluorescein diacetate ($H_2DCFDA$) dye 20 h after culture, examined under a fluorescence microscope, and the fluorescence intensity (pixels) were analyzed in each embryo. The parthenogenetic embryos were cultured for 6 days to evaluate the in vitro development. The apoptosis was measured by TUNEL assay. The $H_2O_2$ levels of parthenogenetic embryos were significantly lower in antioxidant treatment groups ($26.9{\pm}1.6{\sim}29.1{\pm}1.3$ pixels/embryo, p<0.05) compared to control ($33.2{\pm}1.7$ pixels/embryo). The development rate to the blastocyst stage was increased in antioxidant treatment groups (32.0~32.5%) compared to control (26.9%, p<0.05), although, there was no difference in apoptosis among groups. The result suggests that antioxidant treatment during parthenogenetic activation procedure can inhibit the ROS generation and enhance the in vitro development of porcine parthenogenetic embryos.

• Journal of Korean Medical classics
• /
• v.19 no.3
• /
• pp.427-431
• /
• 2006

From 51 monographs of case record in Qing Dynasty, we chose 29 monographs in which tongue diagnosis applied to Warm disease. Then extracted all the case records and got 488 cases from them. In according to the classification of tongue diagnosis in teaching material of TCM diagnosis of higher TCM schools education, we had a statistic analysis on the 488 cases. Results show that the recording rate of tongue coating was highest, 65.16%. From high to low sequentially, the frequency of different fur was yellow fur, white fur and black fur. During $1850{\sim}1911$ of Qing Dynasty, the description of tongue coating changed that the proportion of white fur, yellow fur and compound fur was increased. On the contrary, the proportion of black fur was decreased. The recording rate of the color of tongue was 23.16%, in which the rate of red tongue and crimson tongue were higher. The recording rate of fur character was 37.7%. During $1850{\sim}1911$ of Qing Dynasty, the recording rate of greasy fur was increased to the first. The application of tongue diagnosis involves the warm-heat species of Warm Disease, damp-heat species of Warm Disease and pestilence.

• The Korean Journal of Physiology and Pharmacology
• /
• v.8 no.6
• /
• pp.313-317
• /
• 2004

The present study were designed to characterize the action mechanisms of acetylcholine (ACh)-induced endothelium-dependent relaxation in arteries precontracted with high $K^+$(70 mM). For this, we simultaneously measured both muscle tension and cytosolic free $Ca^{2+}$ concentration $([Ca^{2+}]_i)$, using fura-2, in endothelium-intact, rabbit carotid arterial strips. In the artery with endothelium, high $K^+$ increased both $[Ca^{2+}]_i$ and muscle tension whereas ACh $(10{\mu}M)$ significantly relaxed the muscle and increased $[Ca^{2+}]_i$. In the presence of $N^G$-nitro-L-arginine (L-NAME, 0.1 mM), ACh increased $[Ca^{2+}]_i$ without relaxing the muscle. In the artery without endothelium, high $K^+$ increased both $[Ca^{2+}]_i$ and muscle tension although ACh was ineffective. 4-DAMP (10 nM) or atropine $(0.1{\mu}M)$ abolished ACh-induced increase in $[Ca^{2+}]_i$ and relaxation. The increase of $[Ca^{2+}]_i$ and vasorelaxation by ACh was siginificantly reduced by either $3{\mu}M$ gadolinium, $10{\mu}M$ lanthanum, or by $10{\mu}M$ SKF 96365. These results suggest that in rabbit carotid artery, ACh-evoked relaxation of 70 mM $K^+$-induced contractions appears to be mediated by the release of NO. ACh-evoked vasorelaxation is mediated via the $M_3$ subtype, and activation of the $M_3$ subtype is suggested to stimulate nonselective cation channels, leading to increase of $[Ca^{2+}]_i$ in endothelial cells.

• 제어로봇시스템학회:학술대회논문집
• /
• 1994.10a
• /
• pp.21-29
• /
• 1994

This paper presents a method to accommodate failures that affect aircraft dynamical characteristics, especially control surface jams on a large transport aircraft. The approach is to use the slow effectors, such as the stabilators or engines, in the feedforward manner. The simulation results indicate the performance of the RFCS. In some cases of control surface jam, the aircraft cannot recover without using the stabilators. Although the inputs to the slow effectors are determined using the nominal parameters, the effects of parameter change can be compensated by adjusting the control parameters for the fast surfaces. In the case of rudder jam, if the remaining control surfaces and the differential thrust cancel the moments produced by the stuck rudder, using the engine control improves time responses and reduces deflection angles of the control surfaces. If not, however, the aircraft starts a large rolling motion following a yawing motion. In that case, the stabilators should be used to damp the induced rolliig motion, instead of trying to directly cancel the moments caused by the stuck rudder. Unfortunately, the proposed control law for the stabilators does not give such inputs, because it does not take into account the dynamical effects which stuck surfaces have on the aircraft motions. However, we have shown through simulation that the aircraft can be recovered by giving the stabilators the control inputs that counteract the induced rolling moment. Besides, the method has also been shown through simulation to be effective in maintaining control during a situation similar to an actual accident. Finally let us mention a problem with the RFCS. As stated above, we have not established a method to select a trim point which call be reached as easily as possible using the remaining control effectors. In fact, recovery performance considerably depends on the trim states. As pointed out in Ref. 11, finding the best trim point for impaired aircraft will be one of the most difficult questions in RFCS design.

• The Korea Journal of Herbology
• /
• v.22 no.1
• /
• pp.13-24
• /
• 2007

Objectives : The plans such as Selaginellales, Equisetales and Psilotale have been used for treatment of diseases. Therefore, we examined their effects and distributions. Methods : We examined herbalogical books and research papers which published at home and abroad. Results : 1. There were totaled to 5 genera and 33 species in Selaginellales. Equisetales, Psilotales in Korea and among them medicinal plants are 4 genera, 21 species, about 64% in total. 2. Lycopodium genus is main kind enough that it has 13 species among 33species in the Selaginellales, Equisetales, Psilotales, of which medicinal plants are 10 species. 3. The herb is the main medicinal parts of medicinal plants in the Selaginellales, Equisetales, Psilotales which is used in 21 species. 4. On the bases of nature and flavor of medicinal plants in the Selaginellales, Equisetales. Psilotales, they were classified into neutral 15 species; bitter taste 15 in the order. 5. On the bases of meridian propism of medicinal plants in the Selaginellales, Equisetales. Psilotales, they were classified into liver meridian 11 species. 6. On the bases of the properties and principal curative action, they were classified into drugs for styptic 15 species, drugs for expel wind 14, drugs for drain damp 13 in the order. 7. It has been shown that one species in the Selaginellales, Equisetales, Psilotales is toxic. Conclusion : There were totaled to 5 genera and 33species in Farinales in Korea and among them medicinal plants are 4 genera, 21 species, About 63% in total.

• The Korea Journal of Herbology
• /
• v.22 no.1
• /
• pp.25-34
• /
• 2007

Objectives : The plans can be used for medicinal purposes, among Farinales in korea and examined their effects and distributions. Methods : The examined herbalogical books and research papers which published at home and abroad. Results: 1. There were totaled to 8 genera and 24 species in Farinales Korea and among them medicinal plants arc 8 genera, 11 species, some 46% in total. 2. Eriocaulon is main kind enough that it has 11 species among total 24 species in the Farinales, of which medicinal plants are Commelina and Monochoria that they have each 2 species 3. The herb is the main medicinal parts of medicinal plants in the Farinales which is used in 9 species. 4. According to nature and flavor of medicinal plants in the Farinales, they were classified into cool 9 species; sweet taste 9 in the order. 5. According to meridian propism of medicinal plants in the Farinales, they were classified into liver meridian 6 species. 6. According to the properties and principal curative action. they were classified into drugs for detoxicant 12, drugs for antifebrile 11 species, drugs for drain damp 8 in the order. 7. It was noticed that 1 medicinal plant in the Farinale is toxic. Conclusion: There were totaled to 8 genera and 24 species in Farinales in Korea and among them medicinal plants are 8 genera, 11 species, some 46% in total.

• The Journal of Korean Medical History
• /
• v.33 no.1
• /
• pp.43-57
• /
• 2020

Essence of the Hwangchil tree (黃漆樹 Dendropanax morbiferus H.Lév.) has been used for various purposes, like waxing emperor's armors, covering an astrology board, or, during the Silla Dynasty, burying it to block something bad in the soil symbolically. Essence of the Hwangchil tree was known to have remarkable preservation effects such as waterproofing, damp-proofing, rust-proofing, and moth-proofing as well as not being easily peeled off from even soft surfaces like paper. There is a record in Prescriptions for Epidemic diseases of Cows, Horses, Sheep, and Pigs (牛馬羊猪染疫病治療方), published in 1541, of Hwangchil that is local to Jeju Island being used instead of benzoin (安息香), of burning Hwangchil, and of making cows inhale its smoke to prevent plague among them. Along the same lines, there are records in the Local Chronicle of Tamra (耽羅志) and the Book of Earth Geography (輿地圖書) that identify Hwangchil with benzoin. In Seonghosaseol (星湖僿說), a book written by Lee Yik in around 1760, it is acknowledged that Hwangchil could be medicinal herb. In 2000, Ahn Duk-Kyun registered the roots and branches of Hwangchil tree as 'Boncho' (本草 herbal medicine) in the Pictorial Book of Korean Medicinals (韓國本草圖鑑) and presented the method of taking it for medical purpose. Researchers have suggested that Hwangchil essence as well as diverse parts of the plant such as its roots, branches, leaves, flowers, fruits, and gum have various meaningful medicinal properties. Regarding the history and recent researches of using Hwangchil tree, it has various medicinal probabilities such as, 'dispersing miasma' (辟邪), 'opening holes' (開竅), 'waking the heart' (醒心), 'smoothing spirits' (安神), 'piercing the block' (疎泄), 'removing the old and welcoming the new' (去故生新). This paper contributes ideas about how to expand the uses of Hwangchil Tree.

• Advances in aircraft and spacecraft science
• /
• v.4 no.4
• /
• pp.353-369
• /
• 2017

Flutter is a dangerous phenomenon encountered in flexible structures subjected to aerodynamic forces. This includes aircraft, buildings and bridges. Flutter occurs as a result of interactions between aerodynamic, stiffness, and inertia forces on a structure. In an aircraft, as the speed of the flow increases, there may be a point at which the structural damping is insufficient to damp out the motion which is increasing due to aerodynamic energy being added to the structure. This vibration can cause structural failure, and therefore considering flutter characteristics is an essential part of designing an aircraft. Scientists and engineers studied flutter and developed theories and mathematical tools to analyze the phenomenon. Strip theory aerodynamics, beam structural models, unsteady lifting surface methods (e.g., Doublet-Lattice) and finite element models expanded analysis capabilities. Periodic Structures have been in the focus of research for their useful characteristics and ability to attenuate vibration in frequency bands called "stop-bands". A periodic structure consists of cells which differ in material or geometry. As vibration waves travel along the structure and face the cell boundaries, some waves pass and some are reflected back, which may cause destructive interference with the succeeding waves. This may reduce the vibration level of the structure, and hence improve its dynamic performance. In this paper, for the first time, we analyze the flutter characteristics of a wing with a periodic change in its sandwich construction. The new technique preserves the external geometry of the wing structure and depends on changing the material of the sandwich core. The periodic analysis and the vibration response characteristics of the model are investigated using a finite element model for the wing. Previous studies investigating the dynamic bending response of a periodic sandwich beam in the absence of flow have shown promising results.

• Journal of the Society of Naval Architects of Korea
• /
• v.55 no.1
• /
• pp.56-65
• /
• 2018

Pressure oscillation caused by the compressibility of entrapped air in dam break flow is analyzed using an open source code, which is a two-phase compressible code for non-isothermal immiscible fluids. Since compressible flows are computed based on a pressure-based method, the code can handle the equation of state of barotropic fluid, which is virtually incompressible. The computed time variation of pressure is compared with other experimental and computational results. The present result shows good agreements with other results until the air is entrapped. As the entrapped air bubbles pulsate, pressure oscillations are predicted and the pressure oscillations damp out quickly. Although the compressibility parameter of water has been varied for a wide range, it has no effects on the computed results, because the present equation of state for water is so close to that of incompressible fluid. Grid independency test for computed time variation of pressure shows that all results predict similar period of pressure oscillation and quick damping out of the oscillation, even though the amplitude of pressure oscillation is sensitive to the velocity field at the moment of the entrapping. It is observed that as pressure inside the entrapped air changes quickly, the pressure field in the neighboring water adjusts instantly, because the sound of speed is much higher in water. It is confirmed that the period of pressure oscillation is dominated by the added mass of neighboring water. It is found that the temperature oscillation of the entrapped air is critical to the quick damping out of the oscillations, due to the fact that the time averaged temperature inside the entrapped air is higher than that of surrounding water, which is almost constant.