• Journal of Life Science
• /
• v.30 no.9
• /
• pp.798-803
• /
• 2020

Late in the 1960s, South Korea established cultivation technology and began breeding new "Tongil" type rice cultivars by crossing indica and japonica. To date, this cultivation technique has been used to produce a wide variety of cultivars to meet consumer preferences and adapt to extreme weather conditions. Once major genetic traits are no longer segregated through advanced generations, varieties obtained from a cross between different crops may become a new variety. In this study, we confirmed the agronomic traits of F₄, F₅, and F₆ by advanced generation a population in which drought tolerance and brown planthopper (BPH) resistance were crossed. HV23, Ilmi/HV23, and Drimi2ho/HV23 were used. HV23 was drought-tolerant, and Drimi2ho was resistant to BPH. As a result, it was possible to consider that the agronomic traits were fixed because none of them showed a significant difference from the others. While it takes more than 10 years for the pedigree method of breeding, this study confirmed that the agronomic traits were fixed in 4-6 years. In the future, we will investigate the homology of the CaMsrB2 gene and the Bph1 gene, to confirm that both genes are closely related to each other, and analyze the stable inheritance of the introduced gene for multiple successive generations.

• International Journal of High-Rise Buildings
• /
• v.9 no.2
• /
• pp.127-154
• /
• 2020

Disproportionate collapse triggered by local structural failure may cause huge casualties and economic losses, being one of the most critical civil engineering incidents. It is generally recognized that ensuring robustness of a structure, defined as its insensitivity to local failure, is the most acceptable and effective method to arrest disproportionate collapse. To date, the concept of robustness in its definition and quantification is still an issue of controversy. This paper presents a detailed review on about 50 quantitative measures of robustness for building structures, being classified into structural attribute-based and structural performance-based measures (deterministic and probabilistic). The definition of robustness is first described and distinguished from that of collapse resistance, vulnerability and redundancy. The review shows that deterministic measures predominate in quantifying structural robustness by comparing the structural responses of an intact and damaged structure. The attribute-based measures based on structural topology and stiffness are only applicable to elastic state of simple structural forms while the probabilistic measures receive growing interest by accounting for uncertainties in abnormal events, local failure, structural system and failure-induced consequences, which can be used for decision-making tools. There is still a lack of generalized quantifications of robustness, which should be derived based on the definition and design objectives and on the response of a structure to local damage as well as the associated consequences of collapse. Critical issues and recommendations for future design and research on quantification of robustness are provided from the views of column removal scenarios, types of structures, regularity of structural layouts, collapse modes, numerical methods, multiple hazards, degrees of robustness, partial damage of components, acceptable design criteria.

• Journal of Life Science
• /
• v.18 no.8
• /
• pp.1083-1089
• /
• 2008

We investigated the molecular epidemiological characteristic of methicillin resistant Staphylococcus aureus (MRSA) strains isolated from stool samples in Busan from 2004 to 2006. Among 142 isolates of S. aureus, 49 isolates (34.5%) were confirmed as MRSA. With the antimicrobial susceptibility tests, 37 isolates (75.5%) showed multiple resistance to more than 10 antibiotics, but all isolates were sensitive to vancomycin. All of MRSA had enterotoxin A in 30.6%, B 4.1%, C 8.3%, D, C/G, A 2.0% and None 51%. PFGE of SmaI-digested chromosomal DNA was performed on 49 sporadic MRSA isolates. Restriction fragment patterns consisted of 8 to 14 fragments ranged in size from 48.5 to 630.5 kbp. We could divided the isolates into 7 groups ($I{\sim}VII$) by analyzing PFGE patterns. Group I subdivided as 2 subgroups and 17 (34.7%) strains belong to the group I. Dendrogram of PFGE patterns showed that MRSA strains in Busan were heterogeneous but we could find out minor homogeneity in hospital.

• Research in Plant Disease
• /
• v.8 no.3
• /
• pp.146-161
• /
• 2002

Incidence of soilborne diseases, as a major cause of failure of continuous monocropping becomes severe in recent years. For examples, recent epidemics of club root of chinese cabbage, white rot of garlic, bacterial wilt of potato, pepper phytophthora blight, tomato fusarium wilt and CGMMV of watermelon are the diseases that require urgent control measures. Reasons for the severe incidence of soilborne diseases are the simplified cropping system or continuous monocropping associated with allocation of major production areas of certain crop and year-round cultivation system that results in rapid degradation of soil environment. Neglect of breeding for disease resistance relative to giving much emphasis on high yield and good quality, and cultural methods putting first on the use of chemical fertilizers are thought to be the reason. Counter-measures against soilborne disease epidemics would become most effective when the remedies are seeded for individual causes. As long-term strategies, development of rational cropping system which fits local cropping and economic condition, development and supply of cultivars resistant to multiple diseases, and improvement of soil environment by soil conditioning are suggested. In short-term strategies, simple and economical soil-disinfestation technology, and quick and accurate forecasting methods for soilborne diseases are urgent matter far development. for these, extensive supports are required in governmental level for rearing soilborne disease specialists and activation of collaborating researches to solve encountering problems of soilborne diseases.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.42 no.1
• /
• pp.75-79
• /
• 2015

Pulmonary arterial hypertension (PAH) is a common complication of Congenital heart defects (CHD) with left-to-right shunts, and PAH with increased pulmonary vascular resistance (PVR) is associated with considerable morbidity and mortality. General anesthesia (GA) can be life-threatening in patients with PAH, because the positive pressure ventilation during GA increases pulmonary arterial pressure and decreases pulmonary blood flow. This may also lead to hypoxia. Therefore, spontaneous ventilation may be safer than positive pressure ventilation in patients with PAH. A five-year-old male child, weighing 11 kg, with medical history showing a total correction of Tetralogy of Fallot (TOF) in 2009 and ongoing treatment with hypertension (HTN) medicine since 2007, visited the Dankook University Dental Hospital. He had multiple dental caries, and the treatment was completed under sevoflurane insufflation sedation via nasal cannula. The patient remained sedated throughout the operation while maintaining normal vital signs and spontaneous respiration. In conclusion, sevoflurane insufflation sedation may be a safer alternative to GA for the dental treatment of patients with PAH.

• Journal of Life Science
• /
• v.24 no.2
• /
• pp.196-208
• /
• 2014

During the life cycle of plants, water deficit leads to an adverse effect on its growth and development. To increase the productivity of crops, overcoming such drought stress is one of the most important issues in the field of plant study. Among plant hormones, the phytohormone, abscisic acid (ABA) plays a crucial role in eliciting resistance to drought stress as well as in multiple developmental processes, such as seed germination, stomatal closure, and seedling growth. Therefore, further understanding of the ABA-mediated signal transduction pathway in plants is an effective strategy to generate drought-tolerant plants. Posttranslational modification, such as phosphorylation and ubiquitination, is an efficient mechanism for plants to acquire quick adaptation against environmental stress conditions since this process directly affects pre-existing signaling components by modulating protein activity and stability. Here, recent reports on ABA signaling are reviewed, especially focusing on ABA transport, perception, signaling, and posttranslational modification in ABA-mediated cellular responses. Also, we present future prospects on how the control of such a mechanism can be applied to generate useful agricultural crops.

• Korean Journal of Microbiology
• /
• v.49 no.1
• /
• pp.17-23
• /
• 2013

Candida biofilms are organized microbial communities growing on the surfaces of host tissues or indwelling medical devices, and the biofilms show enhanced resistance against the conventional antifungal agents. The roots of Coptidis chinensis have been widely used for medicinal purposes in East Asia. The present study was aimed to assess the effect of C. chinensis aqueous extract upon preformed biofilms of 10 clinical Candida albicans isolates and the antifungal activities which contribute to inhibit the C. albicans biofilm formation. Its effect on preformed biofilms was judged using XTT [2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide)] reduction assay, and metabolic activity of all tested strains was reduced significantly ($57.3{\pm}14.7%$) at $98{\mu}g/ml$ of the C. chinensis extract. The extract damaged the cell membrane of C. albicans which was analyzed by fluorescein diacetate and propidium iodide staining. The anticandidal activity was fungicidal, and the extract obstructed the adhesion of C. albicans biofilms to polystyrene surfaces, arrested C. albicans cells at $G_o/G_1$ as well, and reduced the growth of biofilms or budding yeasts finally. The data suggest that C. chinensis has multiple antifungal effects on target fungi resulting in preventing the formation of biofilms. Therefore, C. chinensis holds great promise for exploring antifungal agents from natural products in treating and eliminating biofilm-associated Candida infection.

• The Journal of the Korean Society for Microbiology
• /
• v.21 no.3
• /
• pp.399-406
• /
• 1986

This study was performed to establish human plasmacytoma cell line as the partner cells for producing human hybridoma. Bone marrow cells from a multiple myeloma patient from Seoul National University Hospital, Korea were cultured and established as the cell line, named as HMC-BM4. HMC-BM4 cells were cultivated in RPMI 1640 media containing 8-azaguanine(8-AG; gradually increasing concentration from $1\;{\mu}g/ml$ to $20\;{\mu}g/ml$). 8-AG resistant cells were collected and cloned by limiting dilution. Each clone was divided and tested to die in hypoxanthine, aminopterine and thymidine (HAT) selection media. Finally one clone was selected and named as HMC-AR, which was sensitive to HAT selection media. HMC-AR cells showed typical morphology of plamacytoma in Wright staining. No cell formed the rosette with sheep erythrocytes. Surface membrane $\mu$ heavy chain was detected in 20% of HMC-AR cells and cytoplasmic $\mu$ heavy chain in 90% of them by direct immunofluorescent staining. Ia-like antigen was found in 90% of HMC-AR cells by indirect immunofluorescent staining using anti-Ia-like antigen monoclonal antibody, 1BD9-2. And about $1.0\;{\mu}g/ml$ of human $\mu$ heavy chain was detected in the 3-day culture supernatant of HMC-AR cells. 88% of cells contained 46 chromosomes. Mycoplasma was not detected in HMC-AR cells by Hoechst 33258 staining. This cell line would be used for making hybridomas secreting human monoclonal antibody.

• Journal of Yeungnam Medical Science
• /
• v.28 no.2
• /
• pp.133-144
• /
• 2011

Background: Tigecycline (TIG), a new broad-spectrum glycylcycline with anti-multidrug-resistant-(MDR)-pathogen activity, was launched in March 2009 in South Korea, but there are insufficient clinical studies on its use in the country. As such, this study was performed to analyze cases of severe MDR-pathogen-caused infections treated with TIG. Methods: Patients treated with TIG within the period from May 2009 to June 2010 were enrolled in this study. Their clinical and microbiologic data were reviewed retrospectively. Results: Twenty-one patients were treated with TIG for complicated skin and soft-tissue infections (cSSTIs) (42.9%), complicated intra-abdominal infections (cIAIs) (38.1%), or pneumonia (19.1%) caused by MDR pathogens like carbapenem-resistant $Acinetobacter$ $baumannii$ (76.2%), methicillin-resistant $Staphylococcus$ $aureus$ (61.9%), extended-spectrum beta-lactamase-producing $Escherichia$ $coli$ and $Klebsiella$ $pneumoniae$ (38.1%), and penicillin-resistant $Enterococcus$ species (33.3%). Thirteen patients (61.9%) had successful clinical outcomes while five (23.8%) died within 30 days. The rate of clinical success was highest in cSSTI (77.8%), followed by cIAI (50%) and pneumonia (50%), and the mortality rate was highest in pneumonia (50%), followed by cIAI (25%) and cSSTI (11.1%), Conclusion: Tigecycline therapy can be an option for the treatment of severe MDR-pathogen-caused infections in South Korea, Due to its high risk of failure and mortality, however, prudence is required in its clinical use for the treatment of severe infections like nosocomial pneumonia.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.20 no.1
• /
• pp.4575-4591
• /
• 1978

In order to investigate the effects of grain size distribution, cement content, and molding pressure on the strength and durability of soil-cement mixtures, a laboratory test of soil cement mixtures was performed at four levels of cement content, five levels of molding pressure, and four levels of normal curing periods. The results are summarized as follows: 1. Optimum moisture contents in loam soil and maximum dry density in sand soil increased with the increase of cement content, but in others, both optimum moisture contents and maximum dry density were changed ununiformly. 2. When the specimens were molded with molding pressure, 50kg/$\textrm{cm}^2$, strength of soil cement mixture with cement content, 2 and 4 per cent, was lower than the strength of soil cement mixture without cement content by more than 40 to 50 per cent. 3. The strength of soil-cement molded with molding pressure, 100kg/$\textrm{cm}^2$, was higher than the strength of soil-cement molded with M.D.D. obtained from standard compaction test more than 40 per cent in sand loam cement and 50 per cent in loamy cement. 4. There was highly significant positive correlation among molding pressure, cement content and unconfined compressive strentgh and so the following multiple regression equations were obtained. Loam: fc=1.9693C+0.197P-0.84 Sandy loam: fc=2.9065C+0.235P-0.77 5. When the specimens were molded with molding pressure, 20 to 100kg/$\textrm{cm}^2$, the regression equation between the 28-day and 7-day strenght was obtained as follows. Loam : q28=1.1050q7+7.59(r=0.9147) Sandy loam : q28=1.3905q7+3.17 (r=0.9801) 6. At the cement contents of above 50 per cent, the weight losses by freeeze-thaw test were negligible. At the cement content of below 8 per cent the weight losses were singnificantly high under low molding pressure and remarkably decreased with the increase of molding pressure up to 80kg/$\textrm{cm}^2$. 7. Resistance to damage from water and to absorption of water were not improved by molding pressure alone, but when the soil was mixtured with cement above 6 per cent, damage seldoms occurred and absorbed less than 5 per cent of water. 8. There was highly significant inverse-corelationship between the compressive strength of soil cement mixtures and their freeze-thaw loss as well as water absorption. By the regression equation methods, the relationships between them were expessed as followed fc=-7.3206Wa+115.6(r=0.9871) log fc=-0.0174L+1.59(r=0.7709) where fc=unconfined compressive stregth after 28-days curing. kg/$\textrm{cm}^2$ Wa=water absorption, % L : freeze-thaw loss rate, %