Publications by authors named "Jae Sung Jung"

This study simulated the deformation of a hot runner manifold and nozzle assembly during operation, aiming to address potential leaks and premature failure. Both thermal and mechanical models were used simultaneously to accurately capture system behavior. A simplified set of boundary conditions was proposed for efficient problem-solving.

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Bacterial canker is a devastating disease of kiwifruit caused by the bacterium Pseudomonas syringe pv. actinidiae. Canker disease of kiwifruit in Korea has been controlled using streptomycin for more than two decades.

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To determine dimensions in the hot runner systems, given a material, it is necessary to predict the pressure drop according to them. Although modern injection molding simulators are able to evaluate such pressure drops, they are expensive and demanding to be employed as a design utility. This work develops a computer tool that can calculate a pressure drop from the sprue to the gate assuming a steady flow of a generalized Newtonian fluid.

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The bacterial pathogen, pv. actinidiae (Psa), has emerged as a major threat to kiwifruit cultivation throughout the world. One pandemic strain (from the Psa3 group) has occurred in various geographical regions.

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Scab disease caused by is of agroeconomic importance in cultivation of Asian pear. However, little is known about the degree of genetic diversity in the populations of this pathogen. In this study, we collected 55 isolates from pear scab lesions in 13 major cultivation areas in Korea and examined the diversity using sequences of internal transcribed spacer (ITS) region, β-tubulin (TUB2), and translation elongation factor-1 (TEF-1) genes as molecular markers.

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Article Synopsis
  • A study conducted from August to October 2013 identified 210 inland pollution sources impacting Doam Bay, with the majority (66.2%) coming from agricultural activities.
  • Fecal coliform concentrations measured in the water showed the highest levels from domestic discharges, but they were less significant due to low discharge volume.
  • The Tamjin River was the most impactful pollution source, contributing nearly half of the total pollution in Doam Bay, with stream pollution levels fluctuating after rainfall while domestic sources remained unaffected.
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Incidence rates of diseases in kiwiberry orchards were investigated monthly from late June to late September in Gwangyang and Boseong in 2015 and 2016. The impact of postharvest fruit rot was investigated during ripening after harvest. Bacterial canker was only observed on one single tree in 2015, but black rot, powdery mildew, leaf spot and blight, and postharvest fruit rot diseases were problematic throughout the study period in both 2015 and 2016.

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Bacterial canker is the largest limiting factor in the cultivation and production of kiwifruit worldwide. Typical symptoms comprise necrotic spots on leaves, canker and dieback on canes and trunks, twig wilting, and blossom necrosis. pv.

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The causal fungus of pear scab, , grows slowly and rarely produces conidia on artificial media in the laboratory, but it produced conidia on the Cheongah medium containing Cheongah powder. grew too slow to produce conidia until 15 days after cultivation but produced conidia with 4 × 10 conidia/plate 30 days after cultivation on the Cheongah medium containing 1% Cheongah powder. showed a peak production of conidia with 4.

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A bacterial pathogen, pv. (Psa), is a causal agent of kiwifruit bacterial canker worldwide. Psa biovar 3 (Psa3) was first detected in 2011 at an orchard in Dodeok-myeon, Goheunggun, Jeonnam Province in Korea.

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Pseudomonas syringae pv. actinidiae, the causal agent of canker in kiwifruit, can be divided into three biovars (biovars 1, 2, and 3). Strains belonging to biovar 1 produce phaseolotoxin and were isolated in Japan and Italy before 2008.

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A new improved PCR method has been developed for the rapid, reliable, and sensitive detection of Venturia nashicola, a destructive pathogen of scab disease in Japanese pear. The translation elongation factor-1 alpha gene-derived PCR primers specifically amplified a 257-bp-sized DNA band of the target gene from the genomic DNA of V. nashicola.

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The molecular features of Pseudomonas syringae pv. actinidiae strains isolated in Korea were compared with strains isolated in Japan and Italy. Sequencing of eight P.

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The fungus Venturia nashicola is the causal agent of scab on Asian pears. For the rapid and reliable identification as well as sensitive detection of V. nashicola, a PCR-based technique was developed.

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Fifty-three plant-associated microorganisms were investigated for their ability to convert sucrose to its isomers. These microorganisms included one Dickeya zeae isolate and 7 Enterobacter, 3 Pantoea, and 43 Pectobacterium species. Eleven out of the 53 strains (21%) showed the ability to transform sucrose to isomaltulose and trehalulose.

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At present, acetylcholinesterase (AChE) inhibitors are the first group of drugs to treat mild to moderate Alzheimer's disease (AD). Although beneficial in improving cognitive and behavioral symptoms, the effectiveness of AChE inhibitors has been questioned since they do not delay or prevent neurodegeneration in AD patients. Therefore, in the present study, in order to develop new and effective anti-AD agents from lichen products, both the AChE inhibitory and the neuroprotective effects were evaluated.

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Article Synopsis
  • - Two new aerobic bacterial strains, KYW371(T) and KS18, were isolated from seawater and shellfish in Gwangyang Bay, Korea, and belong to the Flavobacteriaceae family.
  • - Phylogenetic analysis showed a high genetic similarity between the two strains, indicating they represent a single species.
  • - The study proposes a new genus and species name, Marinivirga aestuarii, for these isolates and provides updated descriptions for related genera and species in the Flavobacteriaceae family.
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The present study was conducted to evaluate the antibacterial activity of lichen-forming fungi (LFF) against Helicobacter pylori, and to optimize the culture conditions of LFF for maximum production of natural antibiotics against H. pylori. To accomplish this, a screening assay was first conducted among 19 species of LFF.

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Antioxidant properties of 46 lichen species collected from high-UV exposed alpine areas of southwestern China were evaluated for their therapeutic utilization. Anti-linoleic acid peroxidation activity, 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging activity, reducing power and the total phenolic contents were assessed in methanol extract of the lichens in vitro. Extracts of Peltigera praetextata and Sticta nylanderiana exhibited potent activity in all antioxidant tests.

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  • A PCR detection method was developed targeting the hrp gene cluster of Xanthomonas arboricola pv. pruni, which causes bacterial spot on stone fruit.
  • The specific primer set (XapF/R) designed from the amplified hrp region exclusively identified X. arboricola pv. pruni, producing a 243-bp product only from this pathogen.
  • The primer system successfully detected the pathogen in infected peach fruits and was validated as a reliable diagnostic tool in peach orchards.
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A strictly aerobic, red-pigmented, non-motile, catalase- and oxidase-positive, Gram-staining-negative bacterium, designated strain CNURIC011(T), was isolated from seawater off the coast of Jeju Island in Korea. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain CNURIC011(T) belongs to the genus Aquimarina in the family Flavobacteriaceae. 16S rRNA gene sequence analysis revealed that the close relatives of the novel strain are Aquimarina latercula ATCC 23177(T), Aquimarina marcrocephali JAMB N27(T), Aquimarina intermedia KMM 6258(T), Aquimarina muelleri KMM 6020(T), and Aquimarina brevivitae SMK-19(T), with sequence similarities of 97.

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  • A new aerobic bacterium, named K17-16(T), was isolated from the seawater of Gangjin Bay, Korea, and is characterized by its orange pigmentation and negative Gram staining.
  • Phylogenetic analysis revealed it belongs to the Polaribacter genus, showing 94.0-95.6% genetic similarity to known species, indicating it is likely a new species.
  • The bacterium has a G+C content of 34.6 mol%, specific lipids and fatty acids, and is proposed to be named Polaribacter gangjinensis sp. nov., with K17-16(T) as its type strain.
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A novel strictly aerobic, orange-pigmented, Gram-stain-negative bacterium, designated strain GJ16(T), was isolated from coastal seawater of Gangjin Bay, the southernmost part of the Korean peninsula, and subjected to a polyphasic taxonomic study. It grew optimally at 25-30 °C, at pH 7.0-8.

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A novel Gram-negative, aerobic, orange-pigmented bacterial strain, designated K7-2(T), was isolated from seawater of Gangjin Bay, Korea, and subjected to a polyphasic taxonomic study. Strain K7-2(T) contained ubiquinone-10 (Q-10) as the predominant respiratory lipoquinone and did not produce bacteriochlorophyll a. Major fatty acids were C(18 : 1)omega7c (51.

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