• Journal of Applied Biological Chemistry
• /
• v.42 no.3
• /
• pp.119-124
• /
• 1999

About two thirds of the naturally occurring antibiotics have been discovered from actinomycetes. Therefore, the probability of discovering further new antibiotics from actinomycetes is declining as many known metabolites are isolated repeatedly. However, various efforts leave been made in order to enhance the probability of discovering novel compounds. In the present study, we have developed new screening strategies based on the antibiotic biosynthetic pathway, and the genetic information, utilizing polymerase chain reaction. We have selected macrolide type polyketides. In order to divide the ansamycin group antibotic of macrolide type polyketides, we have selected 3-amino-5-hydroxybenzoic acid (AHBA) moiety which contains a biosynthetically unique structural element in the group as a target molecules. Oligonucleotide primers were designed to amplify DNA fragments of macrolide type polyketide synthase and AHBA synthase genes from fourteen actinomycetes species. This method was successfully applied to all three of the known macrolide type polyketide produccing actinomycetes tested. In addition, it also identified the presence of potential macrolide type polyketide producing genes from seven actinomycetes that were known to produce none of macrolide type polyketides, and AHBA biosynthetic genes in one actinomycetes. This technique is potentially useful for the screening of new antibiotices and cloning of their biosynthetic genes.

• Mycobiology
• /
• v.28 no.4
• /
• pp.190-192
• /
• 2000

Antifungal bacteria for biological control of plant diseases or production of novel antibiotics to plant pathogens were isolated in 1997 from various soils of Ansung, Chunan, Koyang, and Paju in Korea. Sixty-four bacterial strains pre-screened from approximately 1,400 strains were tested on V-8 juice agar against eight plant pathogenic fungi using in vitro bioassay technique for inhibition of mycelial growth. Test pathogens were Alternaria mali, Colletotrichum gloeosporioides, C. orbiculare, Fusarium oxysporum f. sp. cucumerinum, F. oxysporum f. sp. lycopersici, Magnaporthe grisea, Phytophthora capsici, and Rhizoctonia solani. A wide range of antifungal activity of bacterial strains was found against the pathogenic fungi, and strain RC-B77 showed the best antifungal activity. Correlation analysis between inhibition of each fungus and mean inhibition of all eight fungi by 64 bacterial strains revealed that C. gloeosporioides would be best appropriate for detecting bacterial strains producing antibiotics with potential as biocontrol agents for plant pathogens.

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.684-687
• /
• 2000

The super-producing recombinant H.polymorpha mutant is obtained by double membrane screening technique combined with optimum mutation method. The characterization of mutant is carried out to find the change of mutant in m-RNA level, cell wall leakage, protease level and methanol utilization metabolic flux. The change of these properties of mutant was figured out.

• Mycobiology
• /
• v.31 no.3
• /
• pp.173-178
• /
• 2003

India has maximum genetic materials in early cauliflower, which grow in subtropical conditions. Different disease parameters like linear growth, maximum growth rate per day, AUDPC, apparent infection rate and percent diseased area were calculated in artificially inoculated plants. Apparent infection rate is not co-related with the black rot disease incidence and should never be considered during characterization of disease resistance and varietal screening. Based on the above disease parameters Kunwari-18, Phool Gobhi Kunwari, Kataki-7 and BT-10-2 were selected as moderately resistance to black rot in early cauliflower. These lines can be used for black rot prone area and also for black rot disease improvement programme. Considering the qualitative and quantitative parameters, slow rotting resistance cauliflower lines are selected as such for cultivation and would be best suited in integrated disease programme.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.22 no.6
• /
• pp.589-598
• /
• 2002

The safe operation of petrochemical plant requires screening of the pipework to ensure that there are no unacceptable levels of corrosion. Unfortunately, each plant has many thousands of metres of pipe, much of which is insulated or inaccessible. Conventional methods such as visual inspection and ultrasonic thickness gauging require access to each point of the pipe which is time consuming and very expensive to achieve. Extensional or torsional ultrasonic guided waves in the pipe wall provide an attractive solution to this problem because they can be excited at one location on the pipe and will propagate many metres along the pipe, returning echoes indicating the presence of corrosion or other pipe features. Guided Ultrasonics Ltd have now commercialised the technique and this paper describes the basis of the method, together with examples of practical test results and typical application areas.

• International Journal of Reliability and Applications
• /
• v.2 no.1
• /
• pp.27-36
• /
• 2001

This Paper proposes a new methodology for assessing the reliability of an accident management, which Is based on the reliability physics and the scheme to generate dynamic event tree. The methodology consists of 3 main steps: screening; uncertainty propagation; and probability estimation. Sensitivity analysis is used for screening the variables of significance. Latin Hypercube sampling technique and MAAP code are used for uncertainty propagation, and the dynamic event tree generation method is used for the estimation of non-success probability of implementing an accident management strategy. This approach is applied in assessing the non-success probability of implementing a cavity flooding strategy, which is to supply water into the reactor cavity using emergency fire systems during the sequence of station blackout at the reference plant.

• Korean Journal of Radiology
• /
• v.22 no.1
• /
• pp.9-22
• /
• 2021

Diffusion-weighted (DW) magnetic resonance imaging (MRI) is a rapid, unenhanced imaging technique that measures the motion of water molecules within tissues and provides information regarding the cell density and tissue microstructure. DW MRI has demonstrated the potential to improve the specificity of breast MRI, facilitate the evaluation of tumor response to neoadjuvant chemotherapy and can be employed in unenhanced MRI screening. However, standardization of the acquisition and interpretation of DW MRI is challenging. Recently, the European Society of Breast Radiology issued a consensus statement, which described the acquisition parameters and interpretation of DW MRI. The current article describes the basic principles, standardized acquisition protocols and interpretation guidelines, and the clinical applications of DW MRI in breast imaging.

• Clinical and Experimental Reproductive Medicine
• /
• v.15 no.1
• /
• pp.1-9
• /
• 1988

The contraception practice rate in Korea has steadily increased from 9% in 1964 to 72% in 1987. Accordingly, natural increase rate of population declined from 28.4 per 1,000 in 1964 to 12.4 per 1,000 in 1987. Notably in recent years, the acceptance of surgical contraception services has sharply increased in this country. Now the author analyzes various factors influencing successful vasectomy and vasovasostomy based on his experience in performing more than 8,000 vasectomies and 1,000 vasovasostomies during the past 25 years. These various factors consist of preoperative screening interview, surgical vasectomy technique, vas irrigation technique, open-ended vasectomy, complications from vasectomy, sperm granuloma formation, spermatogenesis and steroidogenesis after vasectomy, immunological consequences after vasectomy, prostatic diseases and vasectomy, late post-vasectomy syndrome, psychological effects after vasectomy, and success rates of vasovasostomy. Besides, the author makes more comments on the results of the clinical trials on new approaches to reversible vas occlusion technique with a new device of Intravasal Thread and to reversible suppression of spermatogenesis with long-acting sex hormones.

• IEIE Transactions on Smart Processing and Computing
• /
• v.2 no.4
• /
• pp.216-225
• /
• 2013

This paper discusses the issues regarding an abnormal V-shaped error confronting algebraic-based deconvolution process. Deconvolution was applied to an analysis of the effects of the Random Telegraph Noise (RTN) and Random Dopant Fluctuation (RDF) on the overall SRAM margin variations. This paper proposes a technique to suppress the problematic phenomena in the algebraic-based RDF/RTN deconvolution process. The proposed technique can reduce its relative errors by $10^{10}$ to $10^{16}$ fold, which is a sufficient reduction for avoiding the abnormal ringing errors in the RTN deconvolution process. The proposed algebraic-based analyses allowed the following: (1) detection of the truncating point of the TD-MV distributions by the screening test, and (2) predicting the MV-shift-amount by the assisted circuit schemes needed to avoid the out of specs after shipment.

• Korean journal of applied entomology
• /
• v.20 no.4 s.49
• /
• pp.207-211
• /
• 1981

It has been documented that the resistance to planthoppers is attributed to the feeding preference of the insects. This might be related to difference in the amount of feeding plant sap between resistant and susceptible hosts. In this aspect, this study was conducted to verify it and to develop an effective screening method for resistance to planthoppers by tracer technique. An effective P-32 labelling of rice seedlings at $2\~3$ leaf stage was dipping the roots in concentration of $0.1{\mu}Ci/ml$ solution for 48 hours. Radioactivity was significantly higher in planthopers fed on susceptible variety for 48 hours as compared to those fed on resistant variety. Radioactivity of adults was higher than that of nymphs and also higher in female than male. The results were highly correlated to that indicated by the feeding preference of the insects and therefore, considered to be valid for a screening technique.