• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.463-466
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• 1998

A Fusarium species was isolated from stems of cactus(Hylocereus trigonus) showing rot symptoms at Koyang, Kyonggi province in 1997. This pathogen was identified as Fusarium oxysporum based on mycological characteristics. The rot symptom appeared at the soil line and roughly circular lesions, 1∼3 mm in diameter, appeared on basal stems. The pathogen formed both microconidia and macroconidia. Microconidia were formed abundantly in false-heads on short monophialides, oval to kidney-shaped. Macroconidia were slightly sickle-shaped, 3∼5-septated with an attenuated apical cell and a foot-shaped basal cell. Colony color on PDA was white, peach or purple. Chlamydospores were formed abundantly on PDA. The pathogen was able to cause stem rot symptoms to cactus by wound inoculation as well as non-wound inoculation.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.194-207
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• 2021

Vortex-Induced Vibration (VIV) is a major contributor to the fatigue damage of marine risers which are often arranged in an array configuration. In addition to helical strakes and fairings, studies have been strived in searching for possible VIV suppression techniques. Inspired by giant Saguaro Cacti, flexible cylinders of different cactus-shaped cross sections were tested in a water tunnel facility, and test results showed that cactus-like body shapes reduced VIV responses of a cylinder at no cost of significant increase of drag. A series of experiments were conducted on a pair of two tandem-arranged flexible cylinders and an array of four cylinders in a square configuration to investigate the effects of wake on the dynamic responses of cylinders and the VIV mitigation effectiveness of the cactus-like body shape. Results showed that the cylinders in a square configuration, either at the upstream or downstream positions, might have larger dynamic responses than those of a single cylinder. The cactus-like body shape could mitigate VIV responses of cylinders at upstream positions in an array configuration; however, similar to helical strakes, the mitigation efficiency was reduced on downstream cylinders. Note that the cactus-like cross-sectional shape investigated was not optimized for VIV suppression. The present study indicates that the modification of the cross-sectional shape of a cylinder to a well-designed cactus-like shape may be used as an alternative technique to mitigate the VIV of marine risers.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.114.1-114
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• 2003

A new isolate of rod-shaped virus was identified from grafted cactus, Gymnocalycium mihanovichii grafted onto Hylocereus trigonus, in Korea. The virus proved to be a new Tobamovirus and called previously as Tobamovirus-Ca for which we suggest the name Cactus mild mottle virus(CMMoV), because it produced systemic mild mosaic symptoms on its original host. CMMoV is distantly related to known species of the genus Tobamovirus on the basis of host range, serological and sequence analyses. Western blot analysis showed that CMMoV is serologically unrelated to Summons' Opuntia virus which is the only known species of the genus found in cactus plants. The 3'-terminal 2,910 nucleotides have been sequenced for the virus. The coat protein (CP) and movement protein (MP) genes encode 161 and 306 amino acids residues, respectively. The nucleotide and amino acid sequences of the CP were 39.6 ％ to 49.2 ％ and 26.4 ％ to 40.3 ％ identical to other tobamoviruses, respectively. The MP and 3' noncoding region shared 16.3 ％ to 23.3 ％ and 44.6 ％ to 63.4 ％ identities, respectively, with the members of the genus. Phylogenetic tree analysis of the CP gene revealed that CMMoV clusters with members of subgroup I of Tobamovirus. CMMoV particles contained genomic RNA along with two subgenomic RNAs, and this characteristics is common in the members of the subgroup II. This is the first information of sequence and comparative analysis of a Tobamovirus that infects cactus.

• Korean Journal Plant Pathology
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• v.13 no.2
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• pp.73-78
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• 1997

A virus was purified from Korean cactus (Chamaeaereus silverstrii f. Variegata Hort) showing necrotic spots and its biophysicochemical properties were examined. The typical necrotic spots were observed on healthy looking cactus inoculated with the purified virus and the various symptoms from necrotic spots to systemic were observed on 17 species of test plats used, which suggests that the purified virus has the normal infectivity and wide host range. Ultraviolet absorption scanning analysis revealed that the viral preparation had the typical curve with shoulder at 290 nm and its ratio of absorbances at 260 nm to 280 nm and extinction coefficient was 1.156 and 2.86, respectively. The virus represented one distinct and homogeneous band and molecular weight of viral coat protein was determined to 17, 000 Dalton by SDS-PAGE. The virus revealed rod-shaped virion (325$\times$20 nm) by electron microscopy. Based on these results, it has been thought that the virus purified in this study is the pathogenic agents causing necrotic spot symptom on Korean cacuts and one of the member of tobamovirus family.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.435-443
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• 2009

In this paper, we propose a microstrip slot antenna that works in Bluetooth, Zigbee, WiMAX and WLAN frequency bands($2.4{\sim}5.825\;GHz$). To get the wide bandwidth from the microstrip antenna proposed, we insert a pair of parastic strips along the feed line on the FR-4 dielectric substance(${\varepsilon}_r=4.8$). Furthermore, a simple geometrical rotation with quadrilateral slot is designed to maximize the bandwidth and to gain a wider frequency band than the conventional rectangular slot antenna. A additional design of the loop type is added to a cactus-shaped patched for 2.4 GHz ISM frequency band. The total measured bandwidth of the antenna is from 2.4 GHz to 6 GHz and the maximum gains of the antenna are 3.82 dBi, 4.48 dBi, 6.41 dBi and 6.65 dBi at the frequencies of 2.4 GHz, 3.5 GHz, 5.25 GHz and 5.77 GHz.