• 한국어병학회지
• /
• 제32권2호
• /
• pp.123-127
• /
• 2019

In this study, white spots appearing in carapace of imported white leg shrimp Litopenaeus vannamei were observed by macroscopic and microscopic examination. White spots due to white spot disease showed two types, white spots with a regular circular shape ranging from 0.4 mm to 1.7 mm and white spots with an irregular shape ranging from 0.05 mm to 2 mm. White spots due to other causes showed four types that appeared as crystalized materials in range of 100 ㎛ around the tegumental gland, as polygonal inorganic deposits ranging from 58 ㎛ to 188 ㎛, as Linear inorganic deposits ranging from 0.8 mm to 9 mm, as brownish spots ranging from 0.1 mm to 0.4 mm, and brownish spots containing melanin ranging from 0.1 mm to 2 mm. As a result, white spots occurred in imported white leg shrimp Litopenaeus vannamei were divide two type, due to white spot disease or other causes, for quarantine works.

• Nuclear Engineering and Technology
• /
• 제50권5호
• /
• pp.788-793
• /
• 2018

High-density spent fuel (SF) storage racks have been installed to increase SF pool capacity. In these SF racks, neutron absorber materials were placed between fuel assemblies allowing the storage of fuel assemblies in close proximity to one another. The purpose of the neutron absorber materials is to preclude neutronic coupling between adjacent fuel assemblies and to maintain the fuel in a subcritical storage condition. METAMIC neutron absorber has been used in high-density storage racks. But, neutron absorber materials can be subject to severe conditions including long-term exposure to gamma radiation and neutron radiation. Recently, some of them have experienced degradation, such as white spots on the surface. Under these conditions, the material must continue to serve its intended function of absorbing neutrons. For the first time in Korea, this article uses a neutron attenuation test to examine the performance of METAMIC surveillance coupons. Also, scanning electron microscope analysis was carried out to verify the white spots that were detected on the surface of METAMIC. In the neutron attenuation test, there was no significant sign of boron loss in most of the METAMIC coupons, but the coupon with white spots had relatively less B-10 content than the others. In the scanning electron microscope analysis, corrosion material was detected in all METAMIC coupons. Especially, it was confirmed that the coupon with white spots contains much more corrosion material than the others.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2009년 추계학술발표대회
• /
• pp.38-38
• /
• 2009

36 percent nickel-iron alloy possesses a useful combination of low thermal expansion, moderately high strength and good toughness at temperatures down to that of liquid helium, $-269^{\circ}C$. These propeties coupled with good weldability and desirable physical properties make this alloy attractive for many cryogenic applications such as the cargo containment system in Liquefied Natural Gas carriers and pipes for low temperature. Generally, welding method of the 36% nickel-iron is applied with the manual and autogeneous GTAW. Lately white spots have been observed on the some autogeneous GTA welds of them. But the white spot formation have not been studied yet. This paper covers the analysis results of the white spots formation as changing welding variables.

• 한국가금학회지
• /
• 제7권2호
• /
• pp.47-53
• /
• 1980

본 시험은 메추리의 난각과 난각막의 두께 변화를 구명하기 위해서, 공시난 520개로부터 다음과 같은 결과를 얻었다. 1) 메추리 란의 외모색에 따라 구분한 사종의 난각은 그 색에 따라서 대반점백색난각. 대반점난각, 소반점보라난각, 소반점베이지난각으로 구분되고, 그 평균 란중은 8.993g, 8.866g, 8.403g, 8,109g이었다. 2) 사종 난각의 평균 두께는 대기점백색락각이 0.171mm, 대반점각이 0.169mm. 소반점베이지난각이 0.160mm, 소반점보라난각이 0.156mm였다. 3) 사종의 난각막의 평균 두께는 대반점 난각이 0.0449mm. 대연점백색난각이 0.0431mm, 소반점베이지난각이 0.398mm 소반점보라난각이 0.0397mm였다. 4) 난각과 난각막의 두께간에서 빈의 상관계수가 나타났으나 유의성은 없었다. 5) 일반적으로 난각의 두께가 닭에 비하여 매우 엷었다. 그러나 난각막의 두께는 대동소이했다.

• 환경생물
• /
• 제35권4호
• /
• pp.461-467
• /
• 2017

Shrimps infected with WSSV(White Spot Syndrome Virus) generally exhibit white spots in their inner space of carapaces as an acute clinical sign. In an effort to identify the correlation between this acute clinical sign and the condition, the index factors (RNA/DNA concentration and ratio, trypsin activity) were analyzed. A total 580 farmed Fenneropenaeus chinensis and 130 Lithopenaeus vannamei were collected from western and southern fifteen outdoor ponds in Korea. The status of the white spot pathology was divided into four stages (stage 0, stage I, stage II, and stage III), in accordance with the clinical signs as to the size and area of white spots. A significant decrease in RNA concentration and RNA/DNA ratio for multi-infected fleshy prawn (WSSV and vibrio sp.) occurred during the stage III (the whole carapace is covered with a white spot). In particular, RNA/DNA ratio was significantly lower as $1.47{\pm}0.04$ than other groups. A similar trend was also found in the single infection (WSSV), but the decrease was less than the multi-infection. In the species comparison, both species were vulnerable to the multi-infection, but L. vannamei was more sensitive than F. chinensis(ANOVA, p<0.05): A significant decrease in RNA concentration and RNA/DNA ratio was first found in stage II for the former species, while it was found in stage III for the latter species. Trypsin activity was also showed a similar tendency with nucleic acid variation. Multi-infected shrimp showed drastically decrease of trypsin activity. According to the results, clinical signs of the white spot under carapace have an only physiological effect on shrimp if they covered entirely with white spots.

• 대한수의학회지
• /
• 제14권2호
• /
• pp.269-271
• /
• 1974

This investigation was performed to study of chickens naturally infected with leucocytozoon. The results obtained were summarized as follows: 1. The characteristic macroscopical changes observed were hemorrhages and elevated greyish white spots on the oviduct, the liver, the pancreas, the kidney and the pectoral muscles. 2. Microscopically, megaloschizonts were located in groups in the elevated greyish white spots. Hemorrhage and degenerative necrotic changes were observed around the megaloschizonts.

• 대한수의학회지
• /
• 제46권1호
• /
• pp.27-34
• /
• 2006

This paper describes the slaughter check results of breeding pigs from the Korean Swine Testing Station for the control of endemic diseases. Gross lesions monitored in the present study included those conditions commonly associated with economically significant subclinical herd infections: enzootic pneumonia, pleuropneumonia, pleuritis, atrophic rhinitis, liver white spots, papular dermatitis and ileitis. A total of 128 slaughter pigs were investigated at 4 subsequent tests according to the slaughter check procedures established. The prevalence of enzootic pneumonia, pleuropneumonia and pleuritis in the initial test was 67.9%, 28.6% and 17.9%, respectively. However, these were decreased to 46.7%, 6.7% and 6.7%, respectively, in the last test after implementation of counter measures including clean-up protocols and medication programs (p > 0.05). The mean pneumonic score also significantly decreased from 6.8 in the initial test to 2.8 in the last test. The prevalence of atrophic rhinitis (${\geq}score\;2$) was 32.2% and mean atrophic rhinitis score of 1.1 were recorded. However, no significant improvement of conditions was achieved with the counter measures indicating that atrophic rhinitis was originated from the source herds and lesions developed early in the life. In the initial test, prevalence of liver white spots and papular dermatitis lesions was 21.4% and 25.0%, respectively. These conditions were cleaned by the implementation of parasite control measures with all-in all-out, strict clean-up protocols and proper medications adopted in the present study (liver white spots, p = 0.0124; papular dermatitis lesions, p = 0.0055). The prevalence of ileitis lesions in slaughter pigs from the initial test was 28.6%, it could be gradually reduced by the use of repeated treatments and control measures but the effect was not so significant (p > 0.05). In conclusion, slaughter check procedures were successfully established and applied for the control of endemic diseases in the Korean Swine Testing Station.

• 한국표면공학회지
• /
• 제50권5호
• /
• pp.308-314
• /
• 2017

Anodic film formation behavior of AZ31 Mg alloy was studied as a function of NaOH concentration in 1 M $Na_2CO_3$ + 0.5 M $Na_2SiO_3$ solution under the application of a constant anodic current density, based on the analyses of voltage-time curves, surface appearances and morphologies of the anodically formed PEO (plasma electrolytic oxidation) films. The anodic film formation voltage and its fluctuations became largely lowered with increasing added NaOH concentration in the solution. Two different types of film defects, large size dark spots indented from the original surface and locally extruded white spots, were observed on the PEO-treated surface, depending on the concentration of added NaOH. The large size dark spots appeared only when added NaOH concentration is less than 0.2 M and they seem to result from the local detachments of porous PEO films. The white spots were observed to be very porous and locally extruded and their size became smaller with increasing added NaOH concentration. The white spot defects disappeared completely when more than 0.8 M NaOH is added in the solution. Concludingly it is suggested that the presence of enough concentration of $OH^-$ ions in the carbonate and silicate ion-containing electrolyte can prevent local thickening and/or detachment of the PEO films on the AZ31 Mg alloy surface and lower the PEO film formation voltage less than 70 V.

• 한국식물병리학회지
• /
• 제11권4호
• /
• pp.383-385
• /
• 1995

Occurrence of white scab of tea (CAmellia sinensis) showing numerous, small, circular, reddish or yellowish brown spots on young tea leaves was observed at a tea plantation of Boseung, Chonnam, from May to June in 1992-1994. At the late growth stages, the center of the spot became light gray. The causal fungus of the white scab was identified as Sphaceloma theae Kurosawa. Symptoms were produced 5∼6 days after inoculation by the artificial inoculation of s. theae conidia, which was similar to those on naturally infected leaves.

• Asian-Australasian Journal of Animal Sciences
• /
• 제20권3호
• /
• pp.307-312
• /
• 2007

The present study was carried out to investigate differentially expressed chicken muscle proteins using proteomics approach. More than 300 protein spots were investigated for the muscle samples in 2DE gels and the differentially expressed protein spots between pectoralis and peroneus longus muscles from Cornish and White Leghorn breeds were characterized by MALDI-TOF. In pectoralis muscles, PGAM1 protein was detected as differentially expressed between White Leghorn and Cornish breeds. On the other hand, 4 protein spots (SP22, nxf-2, SOD1, TNNI2) were differentially expressed between White Leghorn and Cornish breeds in peroneus longus muscles. These proteins assumed to be related with muscle development, growth, stress, and movements in chicken. In this experimental process, 2D reference map of the chicken muscle proteins was needed and 25 proteins, which were commonly expressed in both pectoralis and peroneus longus muscles in both breeds, were selected and characterized. Upon finishing the exact roles of the differentially expressed proteins, the identified 5 proteins will be used as valuable information for the fundamental mechanisms of muscle biology and underline genetics.