• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.10 no.3
• /
• pp.151-162
• /
• 1977

Distribution of marine algae is diverse in Korea and the resource of edible algae is abundant marking 239,037 tons of yearly production in 1976. They have been known as a protein source and used as a supplement in Korean diet. It is necessary to estimate the potentiality and properties of usable algal proteins especially as food resources and studies of extraction and separation of the proteins, therefore, are basically required for this purpose. In this study, the influence of various factors including the sample treatment, extraction time and temperature, sample us extraction solvent ratio and pH upon the extractability of the water soluble protein was determined. And the effect of precipitation treatment for isolation of the algal protein from the extracts was also tested. Nine species of algae, the major ones in consumption as food namely Porphyra suborbiculata, Undaria pinnatifida, Hizikia fusiforme, Sargassum fulvellu, Enteromorpha linza, Codium fragile, Sargassum kjellmanianum and Ulva pertusa were collected as fresh from Kijang, Yangsan Gun, in the vicinity of Busan city. The content of crude protein $(N\times6.25)$ of the algae ranged from $9.46\%\;to\;24.14\% showing the highest value in Porphyra suborbiculata and the minimum in Hizikia fusiforme. In the effort of maceration of blending methods on the extractability, immersion freezing in dry ice-methanol solution appeared most effective yielding 1.5 to 2.5 times extractability than that of the mortar grinding method. The effect of the ratio of sample vs solvent on extractability differed from species. It was enhanced at the ratio of 1:20 (w/v) in Ulva pertusa and Enteromorpha linza while the ratio was 1:30 (w/v) for Cedium fragile, Undaria pinnatifida, Hizikia fusiferme, Sargassum fulvellum and Porphyra suborbiculata and 1:40 for Sargassum kjellmanianum respectively. The effect of extraction time and temperature was revealed differently from species which might be caused by differences in the constitution of algal tissues resulting in that the extraction for 1 hour at $50^{\circ}C$ gave the maximum extractabilily in Ulva pertusa and Enteromorpha linza, 2 hours in Porphyra suborbiculata, Hikikia fusiforme, Undaria pinnatifida, Sargassum kjellmanianum and 3 hours in Codium fragile. And the extractability was higher at $50^{\circ}C$ to $60^{\circ}C$ for the most of the tested samples except Hizikia fusiforme. The optimum pH for the extraction was 9 to 12. The recovery of extractable nitrogen to the total nitrogen was $63\%$ in average with the first extracts and $8.6\%$ with the second extracts respectively. Both extracts were prepared by 2 hour extraction at $50{\pm}1^{\circ}C$ with dry ice-methanol frozen and seasand macerated materials. And these conditions assumed to be an optimum for the extraction of water soluble algal proteins since the nitrogen content after the first extraction covered $90\%$ of the total water extractable nitrogen. In the precipitation of the extracted proteins, Barnstein method and methanol treatment seemed to be more efficient than other precipitation methods.

• Atmosphere
• /
• v.30 no.1
• /
• pp.31-46
• /
• 2020

The aircraft observation campaign was performed to investigate thermodynamic conditions of snowfall cloud over the East Sea of Korean peninsula from 2 February to 16 March 2018. During this period, four snowfall events occurred in the Yeongdong region and three cases were analyzed using dropsonde data. Snowfall cases were associated with the passage of southern low-pressure (maritime warm air mass) and expansion of northern high-pressure (continental polar air mass). Case 1 and Case 2a were related to low-pressure systems, and Case 2b and Case 3 were connected with high-pressure systems, respectively. And their thermodynamic properties and horizontal distribution of snowfall cloud were differed according to the influence of the synoptic condition. In Case 1 and Case 2a, atmospheric layers between sea surface and 350 hPa contained moisture more than 15 mm of TPW with multiple inversion layers detected by dropsonde data, while the vertical atmosphere of Case 2b and Case 3 were dry as TPW 5 mm or less with a single inversion inversion layer around 750~850 hPa. However, the vertical distributions of equivalent potential temperature (θ_e) were similar as moist-adiabatically neutral condition regardless of the case. But, their values below 900 hPa were about 10 K higher in Case 1 and Case 2a (285~290 K) than in Case 2b and Case 3 (275~280 K). The difference in these values is related to the characteristics of the incoming air mass and the location of the snowfall cloud.

• International Journal of Highway Engineering
• /
• v.12 no.2
• /
• pp.71-79
• /
• 2010

The influence of fines of the frost susceptibility of subgrade soils were established by laboratory freezing system test simulating closely the thermal conditions in the field. During the winter season, the climate is heavily influenced by the cold and dry continental high pressure. Because of siberian air mass, the temperature of January is $-6{\sim}-7^{\circ}C$ on average. This chilly weather generate the frost heaving by freezing the moisture of soil and damage potential of the road structure. In the freezing soil, the ice lenses increase the freeze portion of soil by absorbing the ground water with capillary action. However, the capillary characteristics differ from the sort of soil on the state of freezing condition. In the current design codes for anti-freezing layer, the thickness of anti freezing layer is calculated by freezing depth against the temperature condition. Therefore, they have a tendency of over-design and uniform thickness without the considerations of thermal stability, bearing capacity and frost susceptibility of materials. So, it is essential for studying the appropriateness and bearing capacity besides the seasonal and mechanical properties of pavement materials to take a appropriate and reasonable design of the road structure. In this Paper, the evaluation of frost susceptibility was conducted by means of the mechanical property test and laboratory freezing system apparatus. The temperature, heaving amount, heaving pressure and unfrozen water contents of soil samples, the subgrade soils of highway construction site, were measured to determine the frost susceptibility.

• Journal of the Korean association of regional geographers
• /
• v.22 no.4
• /
• pp.856-874
• /
• 2016

This study aims to figure out the weather and climate environment of Seoul area in S. Korea during 1623~1800, which has not been studied so far, by using daily records of weather conditions and meteorological phenomena in the Daily Records of Royal Secretariat of Joseon Dynasty(承政院日記) together with records of abnormal weather conditions and natural disasters in the Annals of the Joseon Dynasty(朝鮮王朝實錄). During 1500~1760 as a period of the Little Ice Age it was generally cold and dry, particularly cool summers of Seoul area. Changes in weather conditions and meteorological phenomena and climate changes appeared prominently at around 1650, 1710, 1770. The annual numbers of rain days and of snow days began to change largely in the 1640s. The rain(and snow) days reduced significantly in the 1710s~1650s, but increased sharply in the 1710s and later. The rain days in summer rapidly increased after the late 1710s, while the snow days greatly reduced after the mid 1770s. The cloudy days around the 1710s greatly reduced in summer, while slightly increased in winter. The hail days increased significantly in the late 1720s and lasted until the 1760s. The fog days began to reduce after 1770 to the fewer days than the climatic normals of 1981~2010. These times are overall consistent with findings of historical climatological cross-checking data and geophysical biological proxy data, accompanied by a trend of relatively enhanced colder and drier of Seoul area.

• Journal of the Korean earth science society
• /
• v.36 no.2
• /
• pp.190-197
• /
• 2015

This study investigated the paleoclimatic change using diatoms that were extracted from the high-resolution laminated layers of diatom ooze sediment cores GC08-EB01 in the eastern basin of the Bransfield Strait, Antarctica. The range of diatom valves per gram of dry sediment was from $0.4-4.2{\times}10^8g^{-1}$ in quantitative diatom assemblage analysis. Laminations are classified using visually dominant diatom species and terrigenous content. Biogenic diatom ooze laminae characterised by bloom of Corethron crilophilum, Eucampia antarctica, Fragilariopsis curta, F. kerguelensis, Odontella weissflogii, Proboscia inermis, R. styliformis, Thalassiosira antarctica, and Chaetoceros resting spores. Terrigenous laminae characterised by mixed diatom assemblage. The ratio of (Fragilariopsis curta+F. cylindrus)/Thalassiosira antarctica increase in horizons, suggesting increased sea-ice cover in the study area during the late Holocene (cold events). As a result, five cold events are identified on the basis of frequency of the critical taxa throughout the section.

• Parasites, Hosts and Diseases
• /
• v.39 no.2
• /
• pp.177-183
• /
• 2001

The objectives of the present study were to (1) determine the susceptibility of Anopheles sinensis to Korean isolates of Plasmodium vivax, (2) establish a method to collect large quantities of P. vivax sporozoites for use as antigen in seroepidemiological studies, and (3) investigate the characteristics of Korean isolates of P. vivax sporozoites. Females of Anopheles sinensis were collected at non-epidemic area, Seokwha-ri, Cheongwon-gun and Chungcheongbuk-do using tent-trap methods coupled with dry ice. The females were artificially infected with gameiocytes of P. vivax using blood obtained from P vivax malaria patients. Individual mosquitoes were infected using either a parafilm-covered glass feeding apparatus or were allowed to feed on naturally infected volunteers. Mosquitoes were sacrificed between 16 and 18 days post-feeding and an enzyme-linked immunosorbent assay (ELISA) was used to detect sporozoites. Four (33.4%) of 12 mosquitoes, which were fed on naturally infected volunteers directly, were positive for sporozoites. In cases, the mosquitoes allowed to feed on whole blood which were extract from three different patients with heparin treated vacuutainers using a parafilm-covered glass apparatus. Two of 55 (3.6%) were positive which blood sample was maintained at room temperature for 8 hours, 1 of 68 (1.5%) was positive which blood was maintained at $4^{\circ}C$ for 24 hours and 1 of 47 (2.3%) was positive at 4$^{\circ}C$ for 48 hours. The mean number of sporozoites was estimated about 818 (n=8; range of 648-1,056) based on optical density values of ELISA.

• Journal of Chest Surgery
• /
• v.12 no.4
• /
• pp.442-449
• /
• 1979

Although anoxic cardiac arrest produces a dry, quiet field, the ability of the myocardium to withstand the anoxic insult is uncertain. The current growth of interest in the use of various cardioplegic solutions ` has resulted in the development of a number of different solutions. In this study, 51 consecutive cases of elective open heart surgery with the aid of extracorporeal circulation were reviewed retrospectively to compare two methods of myocardial preservation. All of these open heart operations had been performed, using hemodilution principle under the moderate hypothermia at the Department of Thoracic and Cardiovascular Surgery, College of Medicine, Kyungpook National University from December, 1975 to July, 1979. In the 31 consecutive cases that form the anoxic arrest group, the operations were done with intermittent aortic cross-clamping and topical cardiac hypothermia. The heart was cooled topically by cold normal saline, which was converted to ice slush before application to the pericardial sac. Twenty of 51 consecutive cases were assigned to the cold cardioplegic method [the cardioplegic group], in which two kinds of cold cardioplegic solutions [Young solution and G IK solution] were infused into the aortic root proximal to the aortic cross clamp for myocardial preservation. Mean total aortic cross clamp times were 43 minutes in the anoxic arrest group and 67 minutes in the cardioplegic group. In the post-operative period, spontaneous regular heart beatings were recovered in 80 percent of the cardioplegic group as opposed to 25.7 percent of the anoxic arrest group. Ventricular fibrillation requiring DC shock was seen in 32.3 percent of the anoxic arrest group and 10 percent of the cardioplegic group. In the cardioplegic group, mean CPK-MB was one positive value on the first post-operative day, and mean LDH 1 was elevated to 51 0 units/ml on the 2nd post-operative day. These results indicate that protecting the myocardium with cold cardioplegia is superior to use of the anoxic cardiac arrest.

• The Korean Journal of Physiology and Pharmacology
• /
• v.3 no.4
• /
• pp.365-373
• /
• 1999

Somatostatin (SOM) is one of the major neuropeptides in dorsal root ganglion cells, but its role in spinal nociceptive process has not been well known. In present study we aimed to investigate the effect of SOM on the response of dorsal horn neurons to the various types of peripheral nociceptive stimuli in anesthetized cats. Using carbon-filament microelectrode, the single cell activities of wide dynamic range neurons were recorded from the lumbosacral enlargement after noxious mechanical (squeeze), thermal (radiant heat lamp) and cold (dry ice) stimulation to the receptive field. Sciatic nerve was stimulated electrically to evoke $A\;{\delta}-$ and C-nociceptive responses. SOM analogue, octreotide $(10\;{\mu}g/kg),$ was applied intravenously and the results were compared with those of morphine (2 mg/kg, MOR). Systemic SOM decreased the cellular responses to the noxious heat and the mechanical stimulation, but increased those to the cold stimulation. In the responses to the electric stimuli of sciatic nerve, $A\;{\delta}-nociceptive$ response was increased by SOM, while C-nociceptive response was decreased. On the other hand, MOR inhibited the dorsal horn cell responses to all the noxious stimuli. From the above results, it is concluded that SOM suppresses the transmission of nociceptive heat and mechanical stimuli, especially via C-fiber, while it facilitates those of nociceptive cold stimuli via $A\;{\delta}-fiber$.

• Journal of the Korean Chemical Society
• /
• v.16 no.1
• /
• pp.40-45
• /
• 1972

An electron spin resonance study has been made on lysozyme in. frozen aqueous solutions irradiated with $_{60}Co$ r-rays in air at $77^{circ}K.$ Water resonances are dominant when the concentration and the temperature are both below 20% and $130^{circ}K$ respectively. More solute radicals are produced in the solution of higher concentration. Majority of the solute radicals results from direct hit of the radiation. The same types of radicals are induced at $77^{circ}K$ whether the substances are irradiated in the dry state or in frozen aqueous solution. Based on these results, it is assumed that the number of ESR centers produced by the secondary intermolecular radical reacions and stabilized in aqueous solutions may depend on the concentration of the solution, and the presence of water may facilitate the secondary radical reactions occuring in the solute molecules after heat treatment. Majority of the solute radicals above around $193^{circ}K$ are believed to react with oxygen to form peroxytype radicals. However, when the solution is subiected to heat-treatment at $265^{circ}K$ after irradiation at $195^{circ}K$ the peroxy-type resonance was not observed, suggestin that an appreciable amount of oxygen is condensed into the ice, at $77^{circ}K.$ in addition to the oxygen that has already been dissolved in solution and react with solute free radicals during the process of heat-treatment. When the solution contains $H_2O_2$, no water resonance but $HO_2$, type resonance was observed probably indicating that the radiation-induced OH radicals are trapped in $H_2O_2$ aggregates and react readily with $H_2O_2$ molecules to poroduce $HO_2$ type radicals even at $77^{circ}K.$.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.47 no.4
• /
• pp.305-310
• /
• 2002

The performance of 7 sugary (su) and 12 shrunken-2 (sh2) sweet com hybrids which are commercially grown in the United States was tested in Korea. The 100-seed weight of su hybrids (16.5-23.6 g) was much heavier compared to that of sh2 hybrids (10.9-17.5 g). The germination rate of su and sh2 hybrids at $25^{\circ}C$ ranged 93.3-100% and 86.7-98.9%, the emergence rate of su and sh2 hybrids in cold test ranged 78.9-97.8% and 62.2-97.8%, and field emergence rate of su and sh2 hybrids ranged 74.4-100.0% and 79.9-98.2%, respectively. In su hybrids, there was a significantly positive correlation between germination rate at $25^{\circ}C$ and emergence rate in cold test or early growth. In contrast, in sh2 hybrids seed weight was positively correlated with early plant growth, while not with the germination rate at $25^{\circ}C$ or emergence rate in cold test and field. Most sh2 hybrids produced larger and more marketable ears compared to su hybrids although there were significant differences among the hybrids in the same genotype. At harvest (24 days after pollination) soluble solids content of su hybrids (24.3-27.1 Brix %) was much higher than that of sh2 hybrids (13.8-18.0 Brix %), while total sugars of sh2 hybrids (21.4-28.6% on the dry weight basis) was much higher compared to su hybrids (2.4-15.9%). Considering germination and emergence rates, marketable ear production, and total sugar content, 'GCB 70' and 'Sweet Satin' in su hybrids and 'Ice Queen', 'Aspen', 'Sweet Magic', 'Bandit', 'Xtrasweet 82', 'Aspen', and 'Cambella 90' in sh2 hybrids performed better than other hybrids.