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        검색결과 1,093

        341.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The interstellar dust grains are formed and supplied to interstellar space from asymptotic giant branch (AGB) stars or supernova remnants, and become constituents of the star- and planet-formation processes that lead to the next generation of stars. Both a qualitative, and a compositional study of this cycle are essential to understanding the origin of the pre-solar grains, the missing sources of the interstellar material, and the chemical evolution of our Galaxy. The AKARI/MIR all-sky survey was performed with two mid-infrared photometric bands centered at 9 and 18 μ m . These data have advantages in detecting carbonaceous and silicate circumstellar dust of AGB stars, and the interstellar polycyclic aromatic hydrocarbons separately from large grains of amorphous silicate. By using the AKARI/MIR All-Sky point source catalogue, we surveyed C-rich and O-rich AGB stars in our Galaxy, which are the dominant suppliers of carbonaceous and silicate grains, respectively. The C-rich stars are uniformly distributed across the Galactic disk, whereas O-rich stars are concentrated toward the Galactic center, following the metallicity gradient of the interstellar medium, and are presumably affected by the environment of their birth place. We will compare the distributions of the dust suppliers with the distributions of the interstellar grains themselves by using the AKARI/MIR All-Sky diffuse maps. To enable discussions on the faint diffuse interstellar radiation, we are developing an accurate AKARI/MIR All-Sky diffuse map by correcting artifacts such as the ionising radiation effects, scattered light from the moon, and stray light from bright sources.
        4,000원
        344.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A nuclear, biological, chemical (NBC) canister was indigenously developed using active carbon impregnated with ammoniacal salts of copper (II), chromium (VI) and silver (I), and high efficiency particulate aerosol filter media. The NBC canister was evaluated against carbon tetra chloride (CCl4) vapours, which were used as a simulant for persistent chemical warfare agents under dynamic conditions for testing breakthrough times of canisters of gas masks in the National Approval Test of Respirators. The effects of CCl4 concentration, test flow rate, temperature, and relative humidity (RH) on the breakthrough time of the NBC canister against CCl4 vapour were also studied. The impregnated carbon that filled the NBC canister was characterized for surface area and pore volume by N2 adsorption-desorption isotherm at liquid nitrogen temperature. The study clearly indicated that the NBC canister provides adequate protection against CCl4 vapours. The breakthrough time decreased with the increase of the CCl4 concentration and flow rate. The variation in temperature and RH did not significantly affect the breakthrough behaviour of the NBC canister at high vapour concentration of CCl4, whereas the breakthrough time of the NBC canister was reduced by an increase of RH at low CCl4 vapour concentration.
        4,000원
        345.
        2012.06 구독 인증기관·개인회원 무료
        Interferon-tau (IFNT) is regarded, generally, to be the conceptus protein that signals maternal recognition of pregnancy in ruminants. Although the discovery was made over two decades ago, the molecular mechanisms that regulate IFNT expression are not well understood. Previous studies demonstrated that transcription factors, caudal-related homeobox- 2 (CDX2), JUN, ETS2 and a transcriptional coactivator CREB binding protein (CREBBP) positively influenced IFNT gene expression, while OCT4 may exhibit negative regulation. We and others have observed that both CDX2 and OCT4 coexist during early stages of conceptus elongation but as development proceeds, OCT4 expression diminishes. The objective of this study was to evaluate the stimulatory and inhibitory effects of CDX2 and OCT4, respectively, on IFNT gene transcription when evaluated with other transcription factors. Human choriocarcinoma JEG3 cells were co-transfected with an ovine IFNT (-654 base pair)-luciferase reporter (-654-oIFNT-Luc) construct and several transcription factor expression plasmids. When the reporter construct was co-transfected with either CDX2, ETS2 or CJUN, transcription of -654-oIFNT-Luc increased about two-fold compared to -654-oIFNT-Luc alone. When -654-oIFNT-Luc was co-transfected with both c-jun and Ets-2, activity of -654-oIFNT-Luc was increased about four-fold; cotransfection with JUN, ETS2 and CDX2 increased -654-oIFNT-Luc expression 12X, indicating that the stimulatory activity of the transcription factors was additive. OCT4, when cotransfected with -654-oIFNT-Luc, reduced expression of the later about 40% when compared to -654-oIFNT-Luc alone. When co-transfected with JUN and/or ETS2, OCT4 abolished the stimulatory effect of these transcription factors. OCT4 also inhibited the stimulatory activity of CDX2 alone, but not when CDX2 was combined with JUN and/or ETS2. Therefore, when combined with the other transcription factors, CDX2 over the transcriptional inhibitory activity of OCT4. Conversely, when cells were transfected initially with OCT4 (0h) followed by transfection with CDX2, ETS2 and JUN 24 h later, -654-oIFNT-Luc expression was reduced to control (-654-oIFNT-Luc, alone) levels. Not surprisingly, 12S E1A, an inhibitor of transcriptional coactivator CREBBP, reduced stimulation of -654- oIFNT-Luc expression by CDX2, ETS2 and JUN, in combination, by about 40%, indicating that proper transcription complex formation is required for maximum expression. In conclusion, it is suggested that prior to conceptus elongation, pre-existing OCT4 may inhibit IFNT expression, but as elongation proceeds, IFNT expression increases, resulting from incremental increases in CDX2 expression, diminished OCT4 expression, and possibly proper transcription factor complex formation. Key words) Interferon-tau, CDX2, OCT4, transcription
        346.
        2012.05 구독 인증기관·개인회원 무료
        The black cutworm, Agrotis ipsilon (Hufnagel), damages various cultivated crops and is also occasionally a serious pest of turfgrass, especially on golf courses. Essential oils have potential as alternative control agents for insect pests. Sixteen essential oils (anise, camphor, cinnamon, citronella, clove, fennel, geranium, lavender, lemongrass, linseed, neem, peppermint, pine, thyme, turpentine and tea saponin) and paraffin oil were assessed in the laboratory and the green house for their efficacy against black cutworm larvae. Treatment of potted perennial ryegrass with anise, cinnamon, neem, paraffin or turpentine reduced black cutworm damage in a greenhouse trial. Neem oil (2000 ppm) reduced growth of black cutworms feeding on treated clippings within 3 and 5 days. Treatment of perennial ryegrass in pots resulted in 100, 100 and 46% mortality of black cutworm at 4000, 2000 and 1000 ppm, respectively. Weight of survivors at the 1000 ppm rate was 5 fold less than weight of comparably-aged controls.
        347.
        2012.05 구독 인증기관·개인회원 무료
        Teratocytes are originated from embryonic serosal membrane of some endoparasitoid wasps. Cotesia plutellae eggs release teratocytes in parasitoid host hemocoel at hatch in about 150 cells per egg. Teratocytes of C. plutellae were cultured in an insect culture medium for at least 14 days. Teratocytes cultured in vitro showed no increase in cell numbers but increased in cell size. Similarly,teratocytes in parasitized larvae did not increase cell numbers, but increased their cell size. Microinjection of invitro cultured teratocytes in to third instar larvae of nonparasitized Plutella xylostella showed a dose-dependently inhibitory effect on development and larval-pupal metamorphosis. In addition, teratocytes prolonged the immature developmental period and reduced the pupation rate, in which young aged host larvae were more sensitive to teratocytes treatment than old larvae. These results suggest that teratocytes play a crucial role in successful parasitization of C.plutellae by altering host developmental program.
        351.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A study was conducted on four crossbred bulls, used as artificial insemination (AI) sires, to correlate their semen quality with their non return rate (NRR). Semen was collected once a week via an artificial vagina, diluted in egg yolk-citrate and maintained at for three days. It was evaluated for sperm motility, viability, morphology immediately after collection and was examined daily for sperm motility, viability and morphology of acrosome, mid piece and tail for a total of three days. A total of 2016 cows were inseminated by two AI technicians. The proportions of sperm with normal heads were 83.4% (63.7~91.7%), the proportion of spermatozoa exhibiting normal morphology (acrosome, mid piece and tail), motility and viability were 89.2% (82.3~92.0%), 71.3% (61.7~75.0%) and 76.7% (65.7~85.0%), respectively in fresh ejaculates. Sperm motility and sperm viability was significantly ( <0.05) lower in Holstein-Friesian Local bull than in other bulls during all three days of storage. The overall NRR for four bulls was 82.7% (72.9-87.5%). Bulls with higher sperm motility, viability and normal morphology of spermatozoa of individual bull had significantly (each <0.05) higher NRR. The highest ( <0.01) NRR (87.5%) was observed in a Red Chittagong bull whose semen qualities were significantly ( <0.05) higher than Holstein-Friesian Local bull (NNR 72.9%). The results of the present study concluded that NRR at 56 days post AI is related to parameters of semen quality. Therefore, semen evaluation may allow the discarding of bulls with poor fertility in an AI program.
        4,000원
        352.
        2011.11 구독 인증기관·개인회원 무료
        The aim of this study was to investigate the suppressive activity of 70% ethanol extract and its dichloromethane fraction from Auricularia auricula-judae against adipogenesis and lipogenesis in 3T3-L1 preadipocytes. The ethanol extract and its dichloromethane fraction suppressed the differentiation and decreased lipid droplets in vitro. The dose-dependent increasing concentration of glycerol and lower triglycerides accumulation were found significantly (P < 0.05) with the treatment of both fractions from 70% ethanolic Auricularia auricula-judae extract and the glycerol-3-3phosphate dehydrogenase (GPDH) activity was also inhibited by both extracts. Further, the expression of adipogenic mRNAs were investigated by RT-PCR amplification. The key transcriptional factors, PPARγ and C/EBPα were decreased significantly at dose-dependent manner by both extracts of Auricularia auricula-judae. The expressions of LPL and FAS were also decreased by presence of these extracts. The decreased expressions of C/EBPβ, C/EBPγ and ACC1 were observed only by ethanol extract at 300 μg/ml concentration, while the expression of SREBP-1c, GLUT4 and aP2 were not altered in the 3T3-L1 adipocytes. These changes were occurred without the cytotoxic effect of both extracts against 3T3-L1 adipocytes in vitro. A positive control, fenofibrate inhibited the differentiation, triglycerides accumulation through PPARγ signaling by 2/3 reduction of PPARγ expression. Thus, these findings suggest that both extracts of Auricularia auricula-judae might be used to inhibit the differentiation of 3T3-L1 preadipocytes and reduction of triglycerides accumulation.
        353.
        2011.11 구독 인증기관·개인회원 무료
        The aim of this study was to investigate the antitumor activity of solvent fractions from Auricularia auricula-judae 70% ethanol extract and confirmed the active components of dichloromethane fraction showing a potent antitumor activity than other fractions in the broncheoalveolar and gastric cancer cells. The solvent fractions of Auricularia auricula-judae extract, inhibited the growth proliferation of tumor cells in dose-dependent manner. The principle components of dichloromethane fraction were 5,11,17,23-tetrakis (1,1-dimethyl)-28-methoxypentacyclo [19.3.1.1 (3,7).1 (… (65.85%) and diazane (6.17%). The antitumor active components, diazane and gibberellic acid (GA3) were identified in this fraction by GC-MS analysis and lower antitumor activities than dichloromethane fraction. The unknown components of dichloromethane fraction were responsible for its cytotoxic effects on tumor cells. Based on IC50 value, gibberellic acid was little cytotoxic itself. According to PCR amplification, the apoptosis of tumor cells were induced by the down-regulation of Bcl-2 and over-expression of P53 on the presence of solvent fractions, diazane and gibberellic acid. Thus, these findings suggest that the dichloromethane might be used as functional feed additive that suppress the tumor growth in the body than other solvent fractions of Auricularia auricula-judae extracts.
        358.
        2011.10 구독 인증기관·개인회원 무료
        Cell transplantation therapy using adult stem cells has recently been identified as a potential treatment for spinal cord injury (SCI). But, recovery after traumatic SCI is very limited. As dogs are physiologically much more similar to human compared with other traditional mammalian models in disease presentation and clinical responses, a number of researches demonstrated canis familiaris is a suitable model for human diseases. This study investigated the effect of transplantation of canine Mesenchymal Stem Cells (cMSC) and neural-induced cMSC (nMSC) to understand how these cells improve neurological function in canine SCI model. The differentiation of cMSC into neural precursor cells was induced in dulbecco’s modified eagle’s medium supplemented with N2-supplement, dibutyryl cyclic adenosine monophosphate, and butylated hydroxyanisole. SCI was induced between T1 and T2 by surgical hemi-section in adult dogs, and then assigned to two groups according to the applied cell types (cMSC vs nMSC). Pelleted cMSC or nMSC were transplanted directly into the injured site after SCI, respectively. Analysis of motor function after transplantation was evaluated by modified Olby score. Magnetic resonance imaging (MRI), histological and immunohistichemical analysis were also performed. Functional recovery in group of cMSC was increasing gradually after transplantation and was higher than nMSC. In MRI, we could not confirm any difference between the cMSC and nMSC experimental groups. Immunohistochemically, beta3-tubuline and nestin were observed in injury site of two experimental groups with the expression level close to non-injured groups. Transplantation of mesenchymal stem cells could promote neuronal reconstruction and repair motor function in SCI. These showed mesenchymal stem cells could be a great candidate as a therapeutic tools in degeneration disease, and dogs could be used to explore human regenerative medicine as a promising animal model. This research was supported by iPET (Grants 110056032CG000), Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea.
        359.
        2011.10 구독 인증기관·개인회원 무료
        The present research was carried out to evaluate the possibility of female offspring production using artificial insemination buffer (AIB) before artificial insemination (AI). To do it, we carried out the optimization of AIB, making of AIB gun and analysis of affecting AI rate after AIB treatment. AIB made with the base of Tris‐buffer supplemented with L‐arginine and several materials that could be reduced the motility of male sperm compared with female one. This mean that female sperm could be increased the possibility of fertilization with ovum compared with male one. AIB must be deposited into 2nd to 4th cervix by the guide of AIB gun. After 15 min of AIB insertion, frozen semen was deposited into same place after. Total 352 cattle were inseminated with AIB insemination and was not significant difference between AIB and traditional AI rate (56.8 vs. 55.7%). However, AIB AI rate was significantly differs among 12 different farms. The parturition number of cows did not effect on AIB AI rate among 1st to 7th parturition number of cows. The proportion of AIB AI success rates in hanwoo cows was significantly higher than in dairy cows (61.0% vs. 48.7%), but the average AI success rate was not different between AIB and conventional AI (56.8% vs. 55.7%). The female offspring production rate in 2nd to 4th cervix deposition place was significantly higher than in uterus body (77.7% vs. 59.6%, p<0.05). The injection volume of AIB in 5 and 10 ml was significantly higher than in 2 ml (77.7, 78.7 vs. 51.8%, p<0.05), but not different between 5 and 10 ml ABI volume. The best exposure time of AIB in the cervix was 10 and 15 min rather than that of 5 min (79.2%, 77.2% vs. 63.2%, p< 0.05), and so AIB have to expose at least 10 min to get higher female offspring. In conclusion, AIB could be used in AI industry to produce female offspring and also AIB AI can be increased the AI success rate compared with traditional AI rate.
        360.
        2011.10 구독 인증기관·개인회원 무료
        Acteoside (verbascoside) is a typical phenylethanoid glycoside, extracted from various plants. It has various biological functions such as anti-oxidant, anti-inflammation, and anti-hypertension. Specially, it was powerful anti-oxidants either by direct scavenging of reactive oxygen and nitrogen species, or by acting as chain-breaking peroxyl radical scavengers. We examined the role of acteoside in IVM medium on the morphological progress of meiosis, developmental competence, and ROS in porcine oocytes. And we investigated effect of acteoside on the oocytes condition represented by cytoplasmic maturation by homogeneous distribution and formation of cytoplasmic organelles and regulation of apoptosis-related genes. The selected COCs were cultured in TCM-199 with various concentration of acteoside: 0 (control), 10, 30, and 50 μM. After 22 h of maturation with hormones, the oocytes were washed twice in a fresh maturation medium before being cultured in hormone-free medium for additional 22 h. The oocytes maturation rates of supplemented with acteoside were no significantly different compared with control group (71.13, 75.96, 72.95 and 73.68%, respectively). Level of ROS was significantly decreased in acteoside treated group. Furthermore, the parthenogenetic blastocyst rate was significantly improved in 10 μM acteoside treated group compared with control group (40.03 vs. 22.95%). During IVM, 10 μM acteoside treated oocytes showed that the mitochondria and lipid droplet were smaller and homogeneous distribution in cytoplasm compare with non-treated control oocytes. And reverse transcription polymerase chain reaction (RT-PCR) witarthenogenetic blstocysts revealed that acteoside increased the anti-apoptoticgenes, otherwise reibued pro-apoptotic genes. In conclusion, our results represents that addition of acteoside to the IVM medium has a beneficial effect in physiology of porcine oocytes such as viability and activation, providing a improved method for porcine oocytes in vitro.