• Korean Journal of Environmental Biology
• /
• v.40 no.4
• /
• pp.413-422
• /
• 2022

Barnea manilensis is a bivalve which bores soft rocks, such as, limestone or mudstone in the low intertidal zone. They make burrows which have narrow entrances and wide interiors and live in these burrows for a lifetime. In this study, the morphology and the microstructure of the valve of rock-boring clam B. manilensis were observed using a stereoscopic microscope and FE-SEM, respectively. The chemical composition of specific part of the valve was assessed by energy dispersive X-ray spectroscopy (EDS) analysis. 3D modeling and structural dynamic analysis were used to simulate the boring behavior of B. manilensis. Microscopy results showed that the valve was asymmetric with plow-like spikes which were located on the anterior surface of the valve and were distributed in a specific direction. The anterior parts of the valve were thicker than the posterior parts. EDS results indicated that the valve mainly consisted of calcium carbonate, while metal elements, such as, Al, Si, Mn, Fe, and Mg were detected on the outer surface of the anterior spikes. It was assumed that the metal elements increased the strength of the valve, thus helping the B. manilensis to bore sediment. The simulation showed that spikes located on the anterior part of the valve received a load at all angles. It was suggested that the anterior part of the shell received the load while drilling rocks. The boring mechanism using the amorphous valve of B. manilensis is expected to be used as basic data to devise an efficient drilling mechanism.

• Korean Journal of Poultry Science
• /
• v.50 no.4
• /
• pp.203-212
• /
• 2023

This study conducted a diallel-crossbreeding test using four Korean native chicken parent stock lines (YC, YD, CK, and CF) to develop a native commercial layer with high egg-laying performance. A total of 312 chickens in six combinations were examined for various traits, including livability, body weight, age at first egg-laying, hen-day, and hen-housed egg production, egg weight, and egg quality, from hatching to 60 weeks of age. The results showed that the average survival rate was 77.1±18.8% with the YDYC combination having the highest survival rate along with excellent specific combining ability. The YDYC combination exhibited significantly higher body weight compared to the other combinations (P<0.01). The average age at first egg-laying was 121.3±2.5 days, with no significant difference between the combinations. The average hen-day egg production was 74.0±6.4%, and the hen-housed egg production was 181.4±33.8 eggs with the YDCF and YCCK combinations demonstrating the highest laying performance, while the YDYC and CKCF combinations had the lowest (P<0.05). Laying performance was more influenced by specific combining ability than general combining ability. The eggs from the YDYC combination were significantly lighter and had the darkest shell color (P<0.01), whereas the YDCF combination exhibited the thickest eggshells. There was no difference in internal egg quality among combinations, except the YDCF combination had the darkest yolk color. Overall, we concluded that the YCCK combination, characterized by high laying performance and livability, and the YDCF combination with high laying performance and good egg quality are the most desirable combinations for Korean native commercial layers.

• Journal of Aquaculture
• /
• v.21 no.4
• /
• pp.203-212
• /
• 2008

A nutritional demand of oyster, Crassostrea gigas larva as part of research for improving of utilization of microalgae being used for the artificial oyster seed production. The change of body growth and biochemical compositions of larvae were investigated during larvae rearing in hatchery. The larvae were cultured in 60 M/T tank and fed mixture 6 different phytoplankton species, Isochrysis galbana (30%), Cheatoceros gracilis (20%), Pavlova lutheri (20%), Phaeodactylum triconutum (10%), Nannochryis oculata (10%) and Tetraselmis tetrathele (10%). The initial feeding amount was $0.3{\times}10^4cells/mL$ at three times a day to D-shaped larva and the feeding amount had been increased 30% gradually every two day since the larvae were raising. The larvae were developed from D shape to pediveliger stage for 12 days. The daily growth of shell length and hight were $5.8{\sim}30.8\;{\mu}m$ and $8.7{\sim}31.4\;{\mu}m$, respectively and weight gains were changed from D shape to pediveliger as follow: wet weight was $0.52{\sim}15.0\;{\mu}g/larva$, dry weight was $0.2{\sim}6.5\;{\mu}g/larva$, and ash free dry weight was $0.1{\sim}8.5\;{\mu}g/larva$. The larvae growth pattern shown a logarithmic phase from D shape to umbone stage but after that stage shown a exponential growth aspect. The crude protein, crude lipid and nitrogen free extract (NFE) of larvae during rearing periods were analyzed as $6.1{\sim}10.6%$, $0.6{\sim}1.1%$ and 1.0-2.7%, respectively. And the total amino acid contents of the larvae during rearing periods were in order as glutamic acid $1.26{\sim}2.24%$, aspartic acid $0.97{\sim}1.70%$, and methionine $0.12{\sim}0.33%$. Of the total fatty acid in the analyzed larvae, the saturated fatty acid (SSAFA) was decreased from 54.3% (D shaped larvae) to 17.1 % (pediveliger) as larvae development but the total mono-unsaturated fatty acid (${\Sigma}MOFA$) and Poly-unsaturated fatty acid (${\Sigma}PUFA$) were increased from 29.9% and 7.8% to 40.6% and 45.6%, respectively. By the way the each fatty acid of the larvae were composed of palmitic acid $9.89{\sim}36.95%$, oleic acid $12.17{\sim}32.29%$, linoleic acid $1.96{\sim}33.55%$, EPA $2.17{\sim}11.58%$ and DHA $1.95{\sim}4.51%$. As a result of this study, the larvae of oyster were demanded a various nutrients for healthy growth and the feeding control, expecially after umbone stage larvae are a rapidly growing time, is very important for success of artificial seed production.

• Current Research on Agriculture and Life Sciences
• /
• v.1
• /
• pp.67-83
• /
• 1983

The new microsporidia S80 isolated from, Bombyx mori L. in Korea showed ovoid in the morphology of the spores and the size were measured $2.9{\pm}0.28{\mu}$ in length and $1.7{\pm}0.29{\mu}$ width. No other microsporidian spore like this has not been so far isolated from Silkworm. The length of the polar filament extruded in hydrogen peroxide ($H_2O_2$) at $30^{\circ}C$ was $26{\mu}$ of a round cytoplasm on the top. The spores were partly stained with Giemsa, Safranin-O and Gram as the same staining properties as Nosema bombycis, Microsporidia K 79 and other microsporidian spores. The fine structures were observed under scanning eleceron microscope through ultrathin sectioning. The spore wall was composed of three layers ; the thin exospore of an electron dense rippled layer, the thick electron lucent endospore which was thinning considerably at the polar filament insertion point, and the inner limiting membrane. Polar cap present at the sporeapex, with a long polar filament of 12-13 coils, subtending angle of $60^{\circ}$ to spore axis, which is tubular made up of a multilayered and are a benes core, light ring structure enclosing the dance core, the dark ring structure enclosing the inner light ring structure and the other than and light ring structure bounded from cytoplasm. Lamellate polaroplast occupied the anterior part of the spore, and the two neclei with dense nucleoplasm bounded by a double nuclear envelope were cited in the slight downer middle portion of spore. From the characteristics of the shape, size and fine structures, it is certain to reason the Microsporidia S80 belong to the phylum Microspora, class Microspora, order Microsporida, order Microsporida. The shape of two nuclei cited seems to be genus Nosema, but in the classification for the suborder it should be defined wheather pansporoblasts be formed or not and for the genis especial attempts have been made to define the characters which distinguish the disporous genera in the life cycle. Survey through the infection of the bad cocoons during 1980 to 1982 in South Korea the areas contaminated with new microsporidia were revealed 5 provinces of Kyung-Gi, Kang-Won, Chung-Nam and Chun-Nam. Pathological effects inoculated per os at second instar larvae of silkworm, the LD 50 was $7.1{\times}10^7/ml$ as lower pathogenecity than that of Nosema bombycis Naegeli of $1.2{\times}10_7/ml$. While on the other hand the inoculation of the microsporidia at fourth instar larvae lowerd the whole cocoon weight and cocoon shell weight and significant at 1% level. The microsporidia S80 defined it can not be transmitted transovarially from the result of predictive and collective examination of 21 egg batches from the infected female moth.

• Korean Journal of Poultry Science
• /
• v.37 no.1
• /
• pp.51-62
• /
• 2010

This study was conducted to investigate the effects of dietary supplementation of multiple probiotics on the performance, small intestinal microflora and immune response in laying hens and broilers. In Exp.1, a total of 800, 82 wk old Hy-line Brown$^{(R)}$ laying hens were assigned to one of the following five dietary treatment; Control, Antibiotics (avilamycin 6 ppm), Probiotics; PB-M (Micro-ferm$^{(R)}$ 0.2%), PB-L (Lacto-sacc$^{(R)}$ 0.1%), PB-Y (Y University probiotics 0.2%). Each treatment was replicated eight times with 20 birds in each replicate and two birds were housed in each cage. Twenty birds units were arranged according to completely randomized block design. Feeding trial lasted 6 wk under 16 h lighting regimen. The Exp. 2, was conducted with a total of 1,000 broilers chicks (Ross$^{(R)}$). They were divided into five treatments, same as those of Exp. 1. Birds were fed starter (0~3 wk) and grower (4~5 wk) diets. Each treatment was replicated four times with 50 birds per pen comprising of deep litter. In Exp. 1, egg production parameters, such as hen-day and hen-house egg production, egg weight, broken and soft shell egg production, feed intake and feed conversion were not significantly different among treatments. However, strength and thickness of eggshell were significantly (P<0.05) different. Among the probiotics, PB-Y showed the highest strength and thickness of eggshell. Eggshell color, egg yolk color and Haugh unit were not significantly influenced. In Exp. 2, overall weight gain (0~5 wk) and mortality were not significantly different among treatments. However, weight gain of birds from PB-Y treatment during starter (0~3 wk) was significantly lower than the birds from Control and Antibiotic treatment. During the whole period (0~5 wk), birds from Antibiotics treatment had higher feed intake and Production Index (PI) and lower feed conversion than birds from Control treatment. Probiotics treatments were not significantly different from the Control on feed intake and feed conversion. In Exp.1, there were significant (P<0.05) differences in leukocytes parameters, such as white blood cell (WBC), hetrophil (HE), lymphocytes (LY), monocyte (MO), eosinophil (EO) and stress index (SI; HE/LY) in the blood of layers. Birds from Antibiotics and probiotics treatments tended to increase these parameters. In Exp. 2, however, only SI was significantly (P<0.05) decreased in Antibiotics treatments. Concentration of serum immunoglobulin (IgG) were higher (P<0.05) in PB-M and PB-Y treatments when compared with Control treatment in Exp. 1. The population of E. coli significantly (P<0.05) decreased in birds from Antibiotics, PB-L and PB-Y treatments when compared with birds from Control treatment in Exp. 1. Metalbolizability of crude fat decreased significantly (P<0.05) in birds from probiotic treatments in Exp. 2. It was concluded that the response of probiotics on the productivity of layers and broilers were different. Probiotics increased strength and thickness of eggshell in layers, and decreased feed conversion and increased PI in broilers. Leukocytes and IgG tended to increase by supplementation of antibiotics and probiotics in layers. Intestinal E. coli tended to decrease in layers. Digestibility of crude fat of diet decreased in probiotics treatments broilers. Parameters of blood and microbial were more sensitive in layers than broilers.

• Applied Biological Chemistry
• /
• v.18 no.3
• /
• pp.145-166
• /
• 1975

The calcium balance study was carried out to determine the availability of calcium in different sources for chicks and laying hens. The sources of calcium were calcium carbonate (CC), dicalcium phosphate-dihydrate (DCPH), and dicalcium phosphate-anhydride (DCPA) for chicks and calcium carbonate (CC) and oyster shell (OS) for laying hens. The radioisotope dilution method was employed to measure the endogenous excreta calcium during the period of balance study following preliminary feeding. A. Experimental results with chicks: No significant difference was found among feed consumption of chicks fed diets containing different sources of calcium. Body weight gain of chicks was dependent upon the source of calcium. The gain decreased in the order of DCPH, DCPA and CC (P<0.01). The feed conversion efficiency in chicks fed DCPH was better than those in chicks fed CC or DCPA. The average tibia ash contents for chicks fed different sources of calcium were similar. The DCPH was superior to CC or DCPA regarding the calcium content in tibia ash. There were no significant differences among the average calcium contents in plasma trichloracetic acid filtrate in chicks irrespective of calcium sources. The mean apparent retention of calcium by chicks fed DCPH, CC and DCPA were 65.9, 64.0 and 59.9% respectively. The calcium to phosphorus ratios in tibia ash and plasma trichloracetic acid filtrate for chicks fed different sources of calcium were similar. The chicks fed DCPH showed the partition of endogenous excreta calcium in total excreta calcium as 35.6% which was higher than 31.0 or 31.4% for chicks fed CC or DCPA. The endogenous excreta calcium per day per chick in group fed DCPH, DCPA or CC were 17.2, 16.1 and 14.6mg respectively. The true retained calcium per day per chick in group fed DCPH were 109.9 mg which was higher than those observed with CC or DCPA group (P<0.01). The true retention of calcium by the birds fed diets containing DCPH, CC or DCPA were 78.1, 75.1 or 72.6% respectively. B. Experimental results with laying hens: The feed consumption, egg production and feed converion efficiency of laying hens fed diets containing different sources of calcium were similar. Calcium concentration in plasma trichloracetic acid filtrate in laying birds fed CC was equivalent to the value obtained by feeding OS. The apparent calcium retention by laying birds fed CC was 61.6% and it was significantly more than that of hens fed OS of 51.6% (P<0.05). The partition of endogenous excreta calcium in total excreta calcium of laying hens fed CC was 23.5% and this was higher than that of birds fed OS of 15.6%. The laying hens fed CC showed 310 mg of endogenous excreta calcium per day per bird while birds fed OS showed 261mg. The true retention of calcium by layers fed CC was 70.7% against 59.2% for birds fed OS (P<0.05).

• Korean Journal of Heritage: History & Science
• /
• v.50 no.4
• /
• pp.4-19
• /
• 2017

Kim Jeong-gi (pen-name: Changsan, Mar. 31, 1930 - Aug. 26, 2015) made a major breakthrough in the history of cultural property excavation in Korea: In 1959, he began to develop an interest in cultural heritage after starting work as an employee of the National Museum of Korea. For about thirty years until he retired from the National Research Institute of Cultural Heritage in 1987, he devoted his life to the excavation of our country's historical relics and artifacts and compiled countless data about them. He continued striving to identify the unique value and meaning of our cultural heritage in universities and excavation organizations until he passed away in 2015. Changsan spearheaded all of Korea's monumental archeological excavations and research. He is widely known at home and abroad as a scholar of Korean archeology, particularly in the early years of its existence as an academic discipline. As such, he has had a considerable influence on the development of Korean archeology. Although his multiple activities and roles are meaningful in terms of the country's archaeological history, there are limits to his contributions nevertheless. The Deoksugung Palace period (1955-1972), when the National Museum of Korea was situated in Deoksugung Palace, is considered to be a time of great significance for Korean archeology, as relics with diverse characteristics were researched during this period. Changsan actively participated in archeological surveys of prehistoric shell mounds and dwellings, conducted surveys of historical relics, measured many historical sites, and took charge of photographing and drawing such relics. He put to good use all the excavation techniques that he had learned in Japan, while his countrywide archaeological surveys are highly regarded in terms of academic history as well. What particularly sets his perspectives apart in archaeological terms is the fact that he raised the possibility of underwater tombs in ancient times, and also coined the term "Haemi Culture" as part of a theory of local culture aimed at furthering understanding of Bronze Age cultures in Korea. His input was simply breathtaking. In 1969, the National Research Institute of Cultural Heritage (NRICH) was founded and Changsan was appointed as its head. Despite the many difficulties he faced in running the institute with limited financial and human resources, he gave everything he had to research and field studies of the brilliant cultural heritages that Korea has preserved for so long. Changsan succeeded in restoring Bulguksa Temple, and followed this up with the successful excavation of the Cheonmachong Tomb and the Hwangnamdaechong Tomb in Gyeongju. He then explored the Hwangnyongsa Temple site, Bunhwangsa Temple, and the Mireuksa Temple site in order to systematically evaluate the Buddhist culture and structures of the Three Kingdoms Period. We can safely say that the large excavation projects that he organized and carried out at that time not only laid the foundations for Korean archeology but also made significant contributions to studies in related fields. Above all, in terms of the developmental process of Korean archeology, the achievements he generated with his exceptional passion during the period are almost too numerous to mention, but they include his systematization of various excavation methods, cultivation of archaeologists, popularization of archeological excavations, formalization of survey records, and promotion of data disclosure. On the other hand, although this "Excavation King" devoted himself to excavations, kept precise records, and paid keen attention to every detail, he failed to overcome the limitations of his era in the process of defining the nature of cultural remains and interpreting historical sites and structures. Despite his many roles in Korean archeology, the fact that he left behind a controversy over the identity of the occupant of the Hwangnamdaechong Tomb remains a sore spot in his otherwise perfect reputation.

• Journal of Venture Innovation
• /
• v.5 no.1
• /
• pp.107-127
• /
• 2022

Global challenges such as the corona pandemic, climate change and the war-on-tech ensure that the demand who the technologies of the future develops and monitors prominently for will be on the agenda. Development of, and applications in, agrifood, biotech, high-tech, medtech, quantum, AI and photonics are the basis of the future earning capacity of the Netherlands and contribute to solving societal challenges, close to home and worldwide. To be like the Netherlands and Europe a strategic position in the to obtain knowledge and innovation chain, and with it our autonomy in relation to from China and the United States insurance, clear choices are needed. Brainport Eindhoven: Building on Philips' knowledge base, there is create an innovative ecosystem where more than 7,000 companies in the High-tech Systems & Materials (HTSM) collaborate on new technologies, future earning potential and international value chains. Nearly 20,000 private R&D employees work in 5 regional high-end campuses and for companies such as ASML, NXP, DAF, Prodrive Technologies, Lightyear and many others. Brainport Eindhoven has a internationally leading position in the field of system engineering, semicon, micro and nanoelectronics, AI, integrated photonics and additive manufacturing. What is being developed in Brainport leads to the growth of the manufacturing industry far beyond the region thanks to chain cooperation between large companies and SMEs. South-Holland: The South Holland ecosystem includes companies as KPN, Shell, DSM and Janssen Pharmaceutical, large and innovative SMEs and leading educational and knowledge institutions that have more than Invest €3.3 billion in R&D. Bearing Cores are formed by the top campuses of Leiden and Delft, good for more than 40,000 innovative jobs, the port-industrial complex (logistics & energy), the manufacturing industry cluster on maritime and aerospace and the horticultural cluster in the Westland. South Holland trains thematically key technologies such as biotech, quantum technology and AI. Twente: The green, technological top region of Twente has a long tradition of collaboration in triple helix bandage. Technological innovations from Twente offer worldwide solutions for the large social issues. Work is in progress to key technologies such as AI, photonics, robotics and nanotechnology. New technology is applied in sectors such as medtech, the manufacturing industry, agriculture and circular value chains, such as textiles and construction. Being for Twente start-ups and SMEs of great importance to the jobs of tomorrow. Connect these companies technology from Twente with knowledge regions and OEMs, at home and abroad. Wageningen in FoodValley: Wageningen Campus is a global agri-food magnet for startups and corporates by the national accelerator StartLife and student incubator StartHub. FoodvalleyNL also connects with an ambitious 2030 programme, the versatile ecosystem regional, national and international - including through the WEF European food innovation hub. The campus offers guests and the 3,000 private R&D put in an interesting programming science, innovation and social dialogue around the challenges in agro production, food processing, biobased/circular, climate and biodiversity. The Netherlands succeeded in industrializing in logistics countries, but it is striving for sustainable growth by creating an innovative ecosystem through a regional industry-academic research model. In particular, the Brainport Cluster, centered on the high-tech industry, pursues regional innovation and is opening a new horizon for existing industry-academic models. Brainport is a state-of-the-art forward base that leads the innovation ecosystem of Dutch manufacturing. The history of ports in the Netherlands is transforming from a logistics-oriented port symbolized by Rotterdam into a "port of digital knowledge" centered on Brainport. On the basis of this, it can be seen that the industry-academic cluster model linking the central government's vision to create an innovative ecosystem and the specialized industry in the region serves as the biggest stepping stone. The Netherlands' innovation policy is expected to be more faithful to its role as Europe's "digital gateway" through regional development centered on the innovation cluster ecosystem and investment in job creation and new industries.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.17 no.5
• /
• pp.449-470
• /
• 1984

The cercaria of Bacciger herengulae which is parasitized on the gonad of Solen strictus was investigated in order to reveal its entire life history. The area covered for the study was in the vicinity sea of Naechodo, the estuary of the Kum river in the western coast of Korea during the period of 1980-1983. Morphology and development as well as infection rates of sporocyst and cercaria within Solen strictus were examined. For accomplishing the objectives of this study, an artificial infection experiment and some investigations on the second intermediate host, the final host and the growing stages were also studied in both laboratory and natural habitat of Solen strictus. According to the study, it was revealed that the first intermediate hosts were Meretrix lusoria, Solen strictus, Tapes japonica and Laternula limicola, the second intermediate host was Palaemon (Exopalaemon) carinicauda and the final hosts were Konosirus punctatus and Harengula zunasi. A mature sporocyst which was found in the gonad of Solen strictus was $4.0-4.3{\times}0.2-0.21\;mm$ insize, and the cercaia with 27 pairs of setae, each seta consisting of 6 tufts, was $270{\times}147{\mu}m$ in body size and $550{\times}52{\mu}m$ in tail size. Oral sucker($52{\times}42{\mu}m$), pharynx, vental sucker and two testese were obviously seen within the cercaria. The excretory vesicles of cercaria were in V-shape and the flame cell were formula was expressed as 2[(3+3)+(3+3)]=24. The infection of cercaria in the first intermediate host, Solen strictus, was found throughout the year regardlless of the water temperature, and its mean infection rate was $9.67\%$ during the study period. The infection rate fluctuated with temperature, the highest being $28.0\%\;at\;28.0^{\circ}C$ water temperature in July and the lowest $2.4\%\;at\;19.5^{\circ}C$ in October, and it increased in proportion to the shell length on the host. But cercaria was not detected at below 4.0 cm in size of the host. Mature cercariae were found 6 months from May to October when water temperature was above $19.5^{\circ}C$. On the other hand, when water temperature was below $19.5^{\circ}C$, only immature cercariae and sporocysts were found. The cercariae were active for 35 hours and survived for 71 hours at $20^{\circ}C$, and 29 and 34 hours at $25^{\circ}C$ respectively, whereas the cercariae were inactive at less than $20^{\circ}C$ in water temperature. Cercaria, from Solen strictus, approached shrimp of 1-3 cm in body length as its second host. Then, it began to intrude in to the muscle of shrimp after 2-3 hours. The infected cercaria formed cyst after 7-8 hours, and became mature metacercaria. $420{\times}310{\mu}m$ in size, 15 days afer infection. The infection rate of metaceria to shrimp in the laboratory was highest, at $25^{\circ}C$ being $61\%$ and at $20^{\circ}C\;17%$. The infection rate of metacearia in shrimp was highest in the first abdominal segment, followed by cephalothorax, the second, and fifth abdominal segments, and in that order. Also, the infection rate of metacercaria in wild shrimp was high $9.6-11.1\%$ at $26.5^{\circ}C$ in June, and low $1.56-2.5\%$ at $28-29.5^{\circ}C$ from July to August. The infected shrimp with metacercaria was experimentally fed to Konosirus punctatus in the laboratory in order to know its final host. The metacercaria developed into the adult worm, $440-520{\times}310-360{\mu}m$ in size, within the intestine of Konosirus punctatus 20 days after infection. The adult worm was oval shape and $20-24{\times}11-20{\mu}m$ in size. The infection rate of adult worm to Konosirus punctatus and Harengula zunasi ranged 87.3 to $100\%$, the mean being $95.2\%$, regardless of the body length of their hosts. The infection rate was $100\%$ in June and July, but it decreased in September and October. The size and body structure of the trematode observed during the present study were well agreed with those ievestigated by Yamaguti(1938), thus, it may be concluded that the adult worm it identified as Bacciger harengulae.