• Ocean and Polar Research
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• v.26 no.4
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• pp.685-688
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• 2004

The morphology of the post-larva of Liopropoma japonicum of the family serranidae is described from one specimen collected off Jeju Island ($32^{\circ}42'N,\;127^{\circ}45'E$) on May 3, 2001. The body is laterally compressed and caudal peduncle deep at 19.4 mm BL. Anus locates at a vertical through posteriormost(8th) dorsal-fin spine. Dorsal fin rays were VIII, 14; anal fin rays III, 10; pectroal fin rays 16; pelvic fin rays I, 5. A caudal fin is rounded. Length of elongate second and third dorsal-fin spines are 499% and 423% of the body length, respectively. A series of 50 sensory pores on body is elongated to caudal fin. Head spination is well developed. Melanophores are moderately large and dense in the head, and are small and rare in teh neck. Being freshly collected, the body color is yellowish-red and tail is semitransparent. The head is yellowish-red and the brain is dark-red.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.3
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• pp.353-358
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• 1998

Experiments were performed to find out the physico-chemical properties of milt, and morphological changes of cryopreserved spermatozoa in tiger puffer, Takifugu rubripes. The average number of sperm and spermatocrit in milt stripped were $9.81{\pm}0.34{\times}10^{10}/m{\ell}$ and $97.8{\pm}0.8$, respectively. While total lipid concentration from seminal fluid was higher than that from sperm, total protein concentration from sperm was higher than that from seminal fluid, Na and K concentrations in sperm and those in seminal fluid were similar each other, However, glucose from sperm and seminal fluid were not detectable. Spermatozoon of tiger puffer was consisted of head, middle Piece and tail. Size of head showing horseshoe shape was $0.65{\pm}0.10{\mu}m$ in diameter and $1.35{\pm}0.30{\mu}m$ in length. The head fully containing chromatin did not have acrosome. Mitochondrion in middle piece was $0.2{\mu}m$ in average diameter and flagellum showed 9+2 structure. A few of cryopreserved spermatozoa showed morphologically loose or swollen plasma membranes.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.3 no.1
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• pp.116-121
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• 2000

Solid and Papillary epithelial neoplasm of pancreas is a rare and low grade malignant tumor. It develops in 2nd or 3rd decades of young female and located in tail of pancreas predominantly. Prognosis is good despite its various histologic features, which suggest a malignant appearance. We report one case of solid and papillary epithelial neoplasm in head of pancreas in a 11-year-old girl who had been suffered from vomiting and right upper abdominal pain for 3 weeks.

• Journal of The Korean Astronomical Society
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• v.41 no.5
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• pp.139-145
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• 2008

The molecular cloud, embedding AFGL 2591, has a "head-and-tail" structure with a total mass of ${\sim}\;1800\;M_{\odot}$, about half of the mass (${\sim}\;900\;M_{\odot}$) in the head (size ${\sim}\;1.2\;pc$ in diameter), and another half in the envelope (${\sim}\;3.5\;pc$ in the east-west direction). We found a new cloud in the direction toward north-east from AFGL 2591 (projected distance ${\sim}\;2.4\;pc$), which is probably associated with the AFGL 2591 cloud. The $^{12}CO$ spectrum clearly shows a blue-shifted high-velocity wing at around the velocity $-20\;{\sim}\;-10\;km\;s^{-1}$, but it is not clear whether this high-velocity component has a bipolar nature in our observations. The observed CN spectra also show blue-shifted wing component but the existence of the red-shifted component is not clear, either. In some CN and HCN spectra, the highvelocity components appear as a different velocity component, not a broad line-wing component. The dense cores, traced by CN and HCN, exist in the 'head' of the AFGL 2591 cloud with an elongated morphology roughly in the north-south direction with a size of about 0.5 pc. The abundance ratio between CN and HCN is found to be about 2 - 3 within the observed region, which may suggest a possibility that this core is being affected by the embedded YSOs or by possible shocks from outside.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.155-155
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• 2022

Low head, ogee spillways is popularly used to defense against floods as well as to provide water for irrigation. Spillway is also used to assess compliance with water quality regulations by controlling amount of discharge to the downstream of a channel. For the purpose of water resource management and/or environmental aspects as explained above, the flow discharge through spillways need to be correctly rated as a function of geometry and hydraulic variables. Typically, four flow conditions are encountered during the operation of spillway: (a) uncontrolled free flow (UF); (b) uncontrolled submerged flow (US); controlled free flow (CF); and controlled submerged flow (CS), and each condition has a unique rating equation. However, one of the tricky part of the spillway operation is finding correct flow type over the spillway because structures can operate under both submerged and free flow conditions, and the types are continuously changing over time depending on the amount of discharge, head water and tail water elevation. Quite obviously, if the wrong rating curve relationship is applied because of misjudgment of the flow type due to a transition, a serious error can occur. Thus, an hydraulic model study of one of spillway structure located in South Florida was conducted for the purpose of developing transition relationships. In this presentation, US to UF transition is highlighted.

• Korean Journal of Microbiology
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• v.17 no.3
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• pp.97-130
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• 1979

Many industrial processes those employ bacteria are subjected to phage infestations. In L-glutamic acid fermentions using acetic acid, the phage infestations of the organisms have been recently recognized. In efforts to elucidate the sources of phage contamination involved in the abnormal fermentation, a series of study was conducted to isolate the phages both from the contents of abnormally fermented tanks and the soil or sewage samples from the surroundings of a fermentation factory, to define major charateristics of the phage isolates, and finally to determine the correlation between the phage isolates and temperate phages originating from the miscellaneous bacterial species isolated from the soil or sewage samples. The results are summarized as follows; 1) All phages were isolated from the irregular fermentation tanks and soil or sewage samples, and they were designated as phage PR-1, PR-2, PR-3, PR-4, PR-5, PR-6, and PR-7, in the order of isolation. These PR-series phages were proved to be highly specific for the variant strains of Br. lactofermentum only, namely, phage PR-1 and PR-2 for Br. lactofermentum No. 468-5 and phage PR-3~PR-7 for Br. lactofemrentum No. 2256. By cross-neutralization test, the 7 phagescould be subdivided into 3 groups, i. e., phage PR-I and PR-2 the first, phage PR-3, PR-4, PR-5, PR-6 the second, and the phage PR-7 the third. 2) The 7 phages were virulent under the experimental conditions. They produced plaques with clear and relatively sharp margins without distinct halo. The mean sizes of plaques were 1.5mm in diameter for phage PR-1 and PR-2, and 1. Omm for phages PR-3~PR-7. Double layer technique modified by Hongo and described by Adams, was applied to assay of the PR-series phages. The factors influencing the plaques were as follows;young age cells of host bacteria cultured for 3-6 hours represented the largest number and size, optimum was pH 7.0, incubation temperature was $30^{\circ}C$, and agar concentration and amount of overlayer medium were 0.6% and 0.2ml, respectively. 3) PR-series phages were stable in 0.05M tris buffer and 0.1M ammonium acetate buffer solution. The addition of $5{\times}10^{-3}M$ magnesium ion effectively increased the stability. Thermostability experiments indicated that PR-series phages were stable at the teinperture between $50^{\circ}{\sim}55^{\circ}C$ in nutrient medium, $45^{\circ}{\sim}50^{\circ}C$ in buffer solution. However, the phages mere completely inactivated at 603C and 65$^{\circ}$C within 10 minutes. The phages were stable at the range of pH6~9 in nutrient medium and of pH 8-9 in buffer solution, respectively. Exposure of the phages to UV for 25, 60 and 100 seconds resulted in the complete loss of infectivily, respectively. 4) Electron microscopy showed that PR-series phage particles exhibited rather similar morphology, differing in the size All of PR-series phages had a multilateral head and had a simple long tiil about three to five times long as compared with head. By the size, phage PR-1 and PR-2, PR-3, PR-4, PR-5, and PR-6 and PR-7 were classified into same groups, respectively. The head and tail size of phage PR-1, PR-5, PR-5(T) and PR-7 were 85nm, 74nm and 235nm and 350mm, and 72nm and 210nm, respectively. 5) Nucleic acids of PR-series phages were double stranded DNA. The G+C contents of phage PR-1, PR-5 and PR-7 were 56.1, 52.9 and 53.7, respectively. The values of G+C contents derived from the $T_m$ were in agreement with the chemically determined values. 6) PR-series phages effectively adsorbed on their host bacteria at the rate of more than 90% during 5 min. K value for phage PR-1, PR-5 and PR-7 were calculated to be $6{\times}10^9 ml$ per minute, respectiveky. The pH of the medium did effect adsorption rate, but both temperature and age of host cells did not. Generally, optimum adsorption condition of phages seemed to be almost same as optimum growth conditions of host bacteria. 7) In one-step growth experiments, the latent periods at $30^{\circ}C$ for PR-1, and PR-7 were about 70, 50 and 55 min, respectively. The corresponding average burst size was 200, 70 and 90, respectively. Lpsis period according to the multiplicity of infection and a phage series. In case of m. o. i. 100, strain No. 2256 (PR-5) and No. 468-5(PR-1) failed to grow and turbidity decreased after 50 and 70min, respectively. 8) In the lysate of a plaque purified phage PR-5 infected bacteria, there observed 2 types ofphage particles, i. e., phage PR-5 and PR-5 (T) of similar morphology but differing at the length of phage tail, and phage tail like particles. The phage taillike particles could be divided into 4 types by the length. Induction experiments of Br. lactofermentum with UV irradiation, mitomycin C or bacitracin treatment produced neither phage PR-5 (T) or phage tail-like particles. 9) No lysis occured when the growth of 7 strains of miscellaneous bacteria, isolated from soil and sewage samples, were inoculated with either phage PR-5 (T) or phage tail-like particles the inoculation of phage PR-5 pellet resulted in the growth inhibition of the orgainsms in the spot test. The lysates obtained from 3 miscellaneous soil derived bacteria following mitomycin C treatment the growth of Br. lactofermentum, but did not lyze the bacterium.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.1
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• pp.85-95
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• 1998

The broadband ultrasonic transducers have been designed to use in obtaining the broadband echo signals from fish schools in relation to the identification of fish species. The broadening of bandwidth was achieved by attaching double acoustic matching layers on the front face of a Tonpilz transducer consisted of an aluminum head, a piezoelectric ring, a brass tail and to evaluate the performance characteristics, such as the transmitting voltage response(TVR) of transducers. The constructed transducers were tested experimentally and numerically by changing the parameters such as impedances and thicknesses of the head, tail and matching layers, in the water tank. Also, the developed transducer was excited by a chirp signal and the received chirp waveforms were analyzed. According to the measured TVR results, the available 3 dB bandwidth of the transducer with double matching layers of an $Al_O_3/epoxy$ composite of 7 mm thick and a polyurethane window of 18 mm thick was 7.3 kHz with a center frequency of 38.8 kHz, and the maximum and the minimum values of the TVR in this frequency region were 135.7 dB and 132.7 dB re $1\;{\mu}Pa/V$ at 1 m, respectively. Also, the available 3 dB bandwidth of the transducer with double matching layers of an $Al_O_3/epoxy$ composite of 11 mm thick and a polyurethane window of 15 mm thick was 6.2 kHz with a center frequency of 38.6 kHz, and the maximum TVR value in the frequency region was 136.3 dB re $1\;{\mu}Pa/V$ at 1 m. Reasonable agreement between the experimental results and the numerical results for the TVR of the developed transducers was achieved. The frequency dependant characteristics of experimentally observed chirp signals closely matched to the measured TVR results. These results suggest that there is potential for increasing the bandwidth by varying other parameters in the transducer design and the material of the acoustic matching layers.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.3
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• pp.193-203
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• 2018

Capture efficiencies of commercial shrimp trawls may improve if their designs took into better account behavioral responses of wild shrimp to approaching cod-end of the trawls. Here we report results of water tunnel-based experimental studies of responses of wild California target prawns to several different near-realistic netting configurations over a range of water velocities (0.3-0.7 m/s). Netting panels were oriented at parallel to water flows (FP) on the bottom of test section, vertical (VT) or diagonal sloping backward (DG), bottom to top. Behavioral responses were recorded by video camera and analyzed frame by frame. Measured responses included rates of penetrating through netting by behavioral features and tail-flip frequencies. Frequencies of prawn passing through the nets increased with flow speed for both orientations and were higher at given speeds for sloped nets. Other behavioral features (e.g., passage head-or tail-first) also varied significantly with water velocities and netting orientation. Interactions of penetrating rates between netting orientations and flow speeds also were significantly dependent, except for prawn size. Additional studies are needed of other shrimp species and at higher water velocities more similar to actual field operations using trawls to improve size selectivity.

• Korean Journal of Veterinary Research
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• v.48 no.1
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• pp.1-8
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• 2008

The testis and epididymis are important organs of the male reproductive system; the functionis to produce, mature, transport, and store sperm. It is important to understand the localization and expressionof specific proteins based for the studies of its physiological processes. In this study, we investigated theexpression and distribution of galectin-3, one of beta-galactoside-binding proteins, in the testis andepididymis of mouse using western blot and imunohistochemistry. Western blot analysis revealed that theexpression of galectin-3, 29 kDa protein, was low in the testis. In the epididymis, high expression wasdetected in the body and tail part, but moderate expression in the head part. By immunohistochemicalanalysis, we found that positive localization of galectin-3 was detected in some myoid cells and Leydigin the epithelium of epididymis, especially in the epithelium of both body and tail of epididymis. Collectively,these results suggest that galectin-3 is constitutively expressed in the testis and epididymis of mouse withvarying intensity, and the role of galectin-3 in the male reproductive organ may be involved in the specificfunction of its structures.

• Journal of Species Research
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• v.5 no.3
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• pp.318-323
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• 2016

Acrobeles ciliatus (von Linstow, 1877) and Plectus parietinus (Bastian, 1865) are newly collected from Korea. Acrobeles is similar to those nematode belongs to Rhabditidae and Panagrolaimidae by having terminal bulb without medium bulb but different by having complex, vines shaped labial attachment. A. ciliatus differed from other Acrobeles species by lateral fields with two incisures, primary axils U-shaped, and secondary axils V-shaped. Head region set off with the neck, three high labial probolae present, each having 5 tines at inner margins and 5-7 at outer margins, and two elongate apical tines. Also, it differs from the longer female body. Plectus parietinus is distinguished from all other species of Plectus by the prominent hypodermal glands, the relatively small amphid, the distinct and well set-off lips and by the subdorsal distal caudal seta on the left side of the tail. Stoma without stylet. Oesophagus about 1/4 of total body length with terminal bulb. Anus ca. $100{\mu}m$ from posterior extremity. Vulva is at middle of body. Have spinneret on tail tip.