• Journal of Environmental Health Sciences
• /
• v.24 no.2
• /
• pp.126-133
• /
• 1998

Effects of B(a)P on preimplantation mouse embryos in vitro were studied. Preimplantation mouse embryos were exposed to a concentration of 0.3, 1, 3 and 10 $\mu$M B(a)P for 72 hrs. The toxicological effects of B(a)P were evaluated by morphological observation of embryos up to the blastocyst stage, and by measuring DNA, RNA and protein synthesis by radioactive precursor incorporation. At 1 $\mu$M B(a)P did not affect preimplantation development but interfered with hatching and ICM formation. Suppressing effect of ICM formation was dose dependent. At the eight cell stage, the developmental rate was decreased at above 3 $\mu$M of B(a)P. At the blastocyst stage, attachment and trophoblast outgrowth were diminished at the 10 $\mu$M of B(a)P and ICM formation was decreased at 1 $\mu$M of B(a)P. Inner cell number of blastocyst was decreased dose dependently. So, number of ICM was one of the most sensitive and toxicological end point. The RNA incorporation rate of 0.1 $\mu ^3$H-uridine was dosedependent and the protein incroporation of 0.5 $\mu Ci ^{35}$S-methionine showed a significant decrease after 48 hrs. But the DNA incorporation rate of methyl-$^3$H thymidine was not affected. Our results suggested that B(a)P did not affect the DNA replication but transcription was inhibited by dose dependent manner. There delay of development during the blastocyst stage was mainly due to the inhibition of RNA synthesis followed by protein synthesis.

• Bulletin of the Korean Chemical Society
• /
• v.14 no.1
• /
• pp.113-117
• /
• 1993

Good yield synthetic routes for the production of new B-alkyl-dithiaborane clusters are reported. The syntheses of the B-alkyl-dithiaboranes are based on the use of Fischer-type carbene reagents to activate the B-H bonds of dithiaborane for alkyl-addition reactions and are the first examples of transition-mediated reactions of dithiaborane to be reported. Thus, reactions employing arachno-$S_2B_7H_8$- and $(CO)_5M{C(R_1)R_2}$ (M = Cr, W; $R_1 = CH_3,\;C_6H_5;\; R_2 = OCH_3,\;SC_6H_5)$ were found to yield the intermidiate anions I, $[(CO)_5M{C(R_1)R_2S_2B_7H_8}]^-$, which upon protonation gave the corresponding neutral, air-sensitive cluster arachno-4-$RCH_2-6,8-S_2B_7H_8(R=CH_3,\;IIa;\;C_6H_5,\;IIb)$ range from 30 to 35% yield. Complexes IIa and IIb are isoelectronic with arachno-6,8-$S_2B_7H_9$ and, on the basis of the spectroscopic data, are proposed to adopt a similar arachno cage geometry in which an $RCH_2$ units are substituted to 4 position boron atom of the arachno-6,8-$S_2B_7H_9$.

• Journal of Animal Reproduction and Biotechnology
• /
• v.37 no.2
• /
• pp.121-129
• /
• 2022

Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2/B1) is an N6-methyladenosine (m⁶A) RNA modification regulator and a key determinant of prem-RNA processing, mRNA metabolism and transportation in cells. Currently, m⁶A reader proteins such as hnRNPA2/B1 and YTHDF2 has functional roles in mice embryo. However, the role of hnRNPA2/B1 in porcine embryogenic development are unclear. Here, we investigated the developmental competence and mRNA expression levels in porcine parthenogenetic embryos after hnRNPA2/B1 knock-down. HhnRNPA2/B1 was localized in the nucleus during subsequent embryonic development since zygote stage. After hnRNPA2/B1 knock-down using double stranded RNA injection, blastocyst formation rate decreased than that in the control group. Moreover, hnRNPA2/B1 knock-down embryos show developmental delay after compaction. In blastocyste stage, total cell number was decreased. Interestingly, gene expression patterns revealed that transcription of Pou5f1, Sox2, TRFP2C, Cdx2 and PARD6B decreased without changing the junction protein, ZO1, OCLN, and CDH1. Thus, hnRNPA2/B1 is necessary for porcine early embryo development by regulating gene expression through epigenetic RNA modification.

• Journal of Korean Society of Forest Science
• /
• v.70 no.1
• /
• pp.91-102
• /
• 1985

Growth and biomass production of natural stands of Quercus variabilis in relation to tree density were studied to obtain basic guide lines for future tending operation. Two natural stands of Quercus variabilis located at 900m (A stand: 6,600trees/ha, $15.84m^2/ha$, $\frac{19}{17-20}$) and 800m (B stand: 4,300trees/ha, $16.65m^2/ha$, $\frac{20}{17-21}$) elevation in Sancheong, Kyongnam Province were selected for the comparative study and following results were obtained through a sample plot method. After diameter of individual trees in the sample plots was measured, twelve average trees from each diameter class were cut felled to measure dry weight of $W_S$, $W_B$, $W_L$, $W_{Ba}$, and standing biomass and biomass production rates by a allometrior regressions related to $D^2H$. Vertical distribution of leaves along the stems indicated that photosynthesis was carried out 2.2m above the ground in Stand A and 1.2m in Stand B. Maximum photosynthesis was located 4.2m and 6.2m above the ground in Stand A and B, respectively. Leaf area index was 4.25ha/ha for Stand A, and 3.89ha/ha for Stand B. Above-ground standing biomass was 49.51 ton/ha for Stand A and 59.20 ton/ha and net annual production was 6.75 ton/ha/yr. for Stand A and 8.99 ton/ha/yr. for Stand B. The ratio of net annual production to standing biomass was 17.5% for Stand A and 16.7% for Stand B. Net assimilation rate was 2.75kg/kg/yr. for Stand A and 3.58kg/kg/yr. for Stand B. Stem wood production rate was 1.46kg/kg/yr. for Stand A and 2.09kg/kg/yr. for Stand B. Bark production rate was 0.60 kg/kg/yr. for Stand A and 0.34kg/kg/yr. for Stand B. Above data indicated that Stand B utilized growing spaces and sites more efficiently than Stand A. It is concluded chat productivity of natural stands of Quercus variabilis can be enhanced through optimization of basal areas and number of tree per hectare and that sound management of natural oak stands should be based on systematic sampling of the area for periodic productivity estimation.

• Journal of Animal Science and Technology
• /
• v.48 no.6
• /
• pp.805-812
• /
• 2006

The purpose of this study was to investigate the effect of Matrigel on the development of bovine embryos after in vitro fertilization. Bovine embryos were cultured in Ⅰ) SOF+ 0.8% BSA(SOF-B), Ⅱ) SOF+ 0.8% BSA plus 0.8% Matrigel(SOF-M) and III) SOF+0.8% BSA and 10% FBS(SOF-BF). The addition of Matrigel appeared not to increase the proportion of blastocysts (SOF-B, 26.6%; SOF-M, 28.2%; SOF-BF, 26.2%). However, the proportion of hatched blastocysts were significantly increased(P<0.05) by Matrigel(SOF-B, 23.7%; SOF-M, 48.7%; SOF-BF, 18.5%). The means of cell number blastocyst was not significantly different among the treatment groups(SOF-B, 172.7±35.5; SOF-M, 175.1±37.4; SOF-BF, 172.8±38.1). The proportion of apoptotic cells in blastocyst was also found to be not significant among the treatment groups(SOF-B, 3.6±3.2%; SOF-M, 4.3±2.6%; SOF-BF, 4.9±4.3%). In this experiment, Matrigel appeared to support embryonic hatching of bovine embryos. Results suggest that Matrigel, as extracellular matrix components, may be another avenue for formulating more physiological culture system in serum-free culture.

• Korean journal of applied entomology
• /
• v.20 no.2 s.47
• /
• pp.103-106
• /
• 1981

This experiment was carried out to investigate the vertical penetration and diffusion of fumigants for soybean disinfection in jumbo silo. The results were as follows, 1. Using the methylbromide independently as a soybean fumigant, penetration and diffusing velocity of methylbromide gas which moved from the top to the bottom through the vertica1 silo was too rapidly, it was possible to find out more 60mg/l of methylbromide gas concentration at bottom of silo within 4 hours after beginning the fumigation. And it showed the tendency of reducing methylbromide gas concentration gradually over the 10 hours from tile beginning the fumigation. 2. In case of added $CO_2$ gas to the methylbromide as a carrier is much more rapid velocity of penetration and diffusion of methylbromide gas than that of methylbromide gas independently. Therefore methylbromide gas concentration at bottom of silo was detected over the 70mg/l within 1.5 hours after beginning the fumigation.. 3. On the other hand, hence the phostoxin as a soybean fumigant was less velocity of Penetration and diffusion of the gas through the vertical silo compare to methylbromide gas, the phostoxin gas concentration couldn't detect over the 10mg/1 during the whole fumigation period at the bottomside of silo. 4. Test insects (rice weevil; sitophilus oryzae. L.) inserted at bottom of silo for examine the fumigation effect were killed completly by using the methylbromide independently and added $CO_2$ gas to methylbromide, while using the phostoxin the test insects were most alive.

• International Area Studies Review
• /
• v.13 no.3
• /
• pp.527-549
• /
• 2009

This paper investigates the relation of invert U-shape between the M/B ratio and leverage ratio by market, firm size, and a level of technology of firm. Our sample consists of 510 manufacturing firms continually listed on the Korea Securities Market and Kosdaq Market from January 1, 2001 to December 31, 2008. The total sample consists of the Korea Securities Market(large firms, high technology industry) sample of 2,248(1,816, 1,704) observations and the Kosdaq Market(small and medium firms, high technology industry) sample of 1,632(2,264, 2,376) observations. The empirical results show that the relation of invert U shape appears on the sample of the Kosdaq Market, small and medium firms, and high technology industry. However, the relation doesn't appear on the sample of the Korea Securities Market, large firms, and low technology industry. These mutually different results may be caused by the relatively low M/B ratio of the latter.

• Microbiology and Biotechnology Letters
• /
• v.33 no.2
• /
• pp.106-111
• /
• 2005

To investigate the substrate variety of a putative non-metal dependent isomerase, the tagatose-6-phosphate isomerase (E.C. 5.3.1.26) structural genes (lacB; 510bp and lacA; 430bp) of Staphylococcus aureus were subcloned and co-expressed. Based on the substrate configuration, various aldoses were surveyed for substrate of ketose isomerization. Among the 10 aldoses tested, D-ribose and D-allose were isomerized by the enzyme. The subunit A and B showed more than $95\%$ activity for D-ribose and $75\%$ for D-allose in the presence of 1mM EDTA compared with non-EDTA conditions, which implying tagatose-6-phosphate isomerase is a non-metal dependent isomerase. Each of subunit A or subunit B alone showed no activity for any of the substrates tested. The affinity constant ($K_m$) of tagatose-6-phosphate isomerase against D-ribose and D-allose were 26 mM and 142 mM, respectively.

• Journal of the Korea Convergence Society
• /
• v.10 no.2
• /
• pp.301-307
• /
• 2019

The purpose of this study is to evaluate the lap time of K-1 sprint competition and compare the records of the best group and the other groups. Based on these data we are willing to provide them on pace control strategies for improving their performances. The analysis was conducted on 12 elite kayak players, measuring the lap time by every interval after dividing the entire 1,000-meter race into 10 sections of 100 meters. We divide the group A, B, C and D based on their final time records. Two-factor repeated measures ANOVA, One-way ANOVA, and correlation analysis were performed. There were no significant lap time differences in the section of first 200m and last 200m between A, B and C. But the C's lap time of 200m~600m were significantly later than group A and B. Non-superior athletes need to establish strategies to reduce lap time in the middle section.

• Asian Journal of Atmospheric Environment
• /
• v.6 no.2
• /
• pp.73-82
• /
• 2012

This study was aimed to thoroughly estimate the characteristics of indoor particulate matter (PM) collected on subway platforms by the cooperative approach of semi-bulk and single particle analyses. The size-resolved PM and its number concentration were measured on the platform in a heavily traveled subway station in Fukuoka, Japan. Particle Induced X-ray Emission (PIXE) and micro-PIXE techniques were applied to the chemical analyses of semi-bulk and single particle, respectively. There was the close resemblance of timely fluctuation between PM number concentration and train service on the third basement floor (B3F) platform compared to the second basement floor (B2F) and its maximum level was marked in rush hour. Higher number counts in large particles ($>1{\mu}m$) and lower number counts in fine particles ($<1{\mu}m$) were shown on the platform compared to an above ground. PM2.5 accounted for 58.2% and 38.2 % of TSP on B3F and on B2F, respectively. The elements that were ranked at high concentration in size-resolved semi-bulk PM were Fe, Si, Ca, S, and Na. The major elements tending to have more elevated levels on B3F than B2F were Fe (4.4 times), Ca (17.3 times), and Si (46.4 times). Although concentrations were very low, Cr ($11.9ng\;m^{-3}$ on B3F, $2.4ng\;m^{-3}$ on B2F), Mn ($3.4ng\;m^{-3}$ on B3F, $0.9ng\;m^{-3}$ on B2F), and Pb ($0.6ng\;m^{-3}$ on B3F, $1.6ng\;m^{-3}$ on B2F) were detected from PM2.5. Individual PM was nearly all enriched in Fe with Si and Ca. Classifying and source profiling of the individual particles by elemental maps and particle morphology were tried and particles were presumably divided into four groups (i.e., train/rail friction, train-rail sparking, ballast/abrasive, and cement).