Malic Acid 혹은 Citric acid 의 첨가가 반추위 혼합미생물의 성장 및 대사에 미치는 영향

고주,이성실,노영애,김홍대,하종규,감동근,전현식 한국영양사료학회 1999 韓國營養飼料學會誌 Vol.23 No.3

본 연구는 malic acid와 citric acid의 첨가가 반추위 혼합미생물의 성장 및 대사에 미치는 영향을 구명하기 위해서 실시되었는데, 시험결과를 요약하면 다음과 같다. Malic acid와 citric acid를 각각 혼합미생물의 배지에 첨가했을 때 배양 12∼24시간에서 두 처리구에서 모두 박테리아의 성장이 크게 촉진되었어며 citric aicd의 첨가효과가 malic acid보다 더 좋았고 박테리아중 amylase를 분비하는 박테리아가 주로 많이 성장하였다. 그리고 곰팡이는 12∼24시간까지는 malic acid와 citric acid 첨가구에서 모두 대조구에 비하여 유의성있게 증가하다 48시간 후에는 급격히 감소하였다. 따라서 섬유소 분해효소의 활력도 48시간부터 급격히 감소하는 것으로 나타났다. This study was conducted to evaluate the effects of malic or citric acid on the growth and cellulolytic activity of mixed rumen microbes. The mixed rumen microbes were inoculated into Lowe's medium containing 0.01% malic or citric acid, and incubated for 12, 24, 48, 72, 120 and 168 hours. After incubation, enzyme (CMCase, xylanase, amylase and protease) activity, microbial growth and gas production were estimated. Results were obtained as below Bacterial growth rate and amylase activity were increased by addition of 0.01% malic acid or citric acid at 12 and 24 hour after incubation, and this stimulatory effect was more obvious with citric acid than with malic acid. Malic or citric acid addition increased fungal growth and cellulolytic enzyme activity upto 24 hour incubation.

Relationship Between K_trans and K₁ with Simultaneous Versus Separate MR/PET in Rabbits with VX2 Tumors

Lee, K. H.,Kang, S. K.,Goo, J. M.,Lee, J. S.,Cheon, G. J.,Seo, S.,Hwang, E. J. INTERNATIONAL INSTITUTE OF ANTICANCER RESEARCH 2017 Anticancer research Vol.37 No.3

<P>Background/Aim: To compare the relationship between Ktrans from DCE-MRI and K1 from dynamic (NNH3)-N-13- PET, with simultaneous and separate MR/PET in the VX-2 rabbit carcinoma model. Materials and Methods: MR/PET was performed simultaneously and separately, 14 and 15 days after VX-2 tumor implantation at the paravertebral muscle. The Ktrans and K-1 values were estimated using an in-house software program. The relationships between Ktrans and K-1 were analyzed using Pearson's correlation coefficients and linear/non-linear regression function. Results: Assuming a linear relationship, Ktrans and K-1 exhibited a moderate positive correlations with both simultaneous ( r=0.54-0.57) and separate ( r=0.53-0.69) imaging. However, while the Ktrans and K-1 from separate imaging were linearly correlated, those from simultaneous imaging exhibited a non-linear relationship. The amount of change in K-1 associated with a unit increase in Ktrans varied depending on Ktrans values. Conclusion: The relationship between K-trans and K-1 may be mis-interpreted with separate MR and PET acquisition.</P>

A biosynthetic pathway for hexanoic acid production in Kluyveromyces marxianus

Cheon, Y.,Kim, J.S.,Park, J.B.,Heo, P.,Lim, J.H.,Jung, G.Y.,Seo, J.H.,Park, J.H.,Koo, H.M.,Cho, K.M.,Park, J.B.,Ha, S.J.,Kweon, D.H. Elsevier Science Publishers 2014 Journal of biotechnology Vol.182 No.-

Hexanoic acid can be used for diverse industrial applications and is a precursor for fine chemistry. Although some natural microorganisms have been screened and evolved to produce hexanoic acid, the construction of an engineered biosynthetic pathway for producing hexanoic acid in yeast has not been reported. Here we constructed hexanoic acid pathways in Kluyveromyces marxianus by integrating 5 combinations of seven genes (AtoB, BktB, Crt, Hbd, MCT1, Ter, and TES1), by which random chromosomal sites of the strain are overwritten by the new genes from bacteria and yeast. One recombinant strain, H4A, which contained AtoB, BktB, Crt, Hbd, and Ter, produced 154mg/L of hexanoic acid from galactose as the sole substrate. However, the hexanoic acid produced by the H4A strain was re-assimilated during the fermentation due to the reverse activity of AtoB, which condenses two acetyl-CoAs into a single acetoacetyl-CoA. This product instability could be overcome by the replacement of AtoB with a malonyl CoA-acyl carrier protein transacylase (MCT1) from Saccharomyces cerevisiae. Our results suggest that Mct1 provides a slow but stable acetyl-CoA chain elongation pathway, whereas the AtoB-mediated route is fast but unstable. In conclusion, hexanoic acid was produced for the first time in yeast by the construction of chain elongation pathways comprising 5-7 genes in K. marxianus.

Dynamic Mesh 기법을 통한 X-형 제어판 배치 잠수함의 가상구속모형시험

천기현(K.H. Cheon),석우찬(W.C. Seok),박종열(J.Y. Park),서정화(J.H. Seo),이신형(S.H. Rhee) 한국전산유체공학회 2018 한국전산유체공학회지 Vol.23 No.2

X-form configuration of a submarine has advantages of better manoeuvrability than the cruciform configuration, which has been traditionally used. The X-form configuration has a much longer span of control planes than those of the cruciform configuration, so it has the advantage of generating larger control force. Its control system, however, is complex, because horizontal and vertical forces induced by control planes were coupled. For the reason above, its dynamic characteristics should be analysed by identifying a dynamic modelling and deriving hydrodynamic derivatives. The present study carried out for a submarine with an X-form configuration. The test model was BB2, of which design was open most recently by Maritime Research Institute Netherlands. The hydrodynamic force on the BB2 model was estimated using virtual Planar Motion Mechanism test using Computational Fluid Dynamics(CFD). To to this, SNUFOAM, an object-oriented open source CFD tool-kit, was used as a solver for Unsteady Reynolds-Averaged Navier-Stokes simulation. Standard k-ε was selected for turbulence model and dynamic mesh methods was used for dynamic PMM tests.

미량원소 함유 K₂O-CaO-P₂O₅계 유리의 작물배지 응용 및 친환경성

이회관(Lee H.K.),강원호(Kang W.H.),채제천(Chae Je-Cheon) 한국산학기술학회 2005 한국산학기술학회 학술대회 Vol.- No.-

본 연구에서는 미량원소 함유 K₂O-CaO-P₂O₅유리를 제조하였으며, 화학비료와의 혼합을 통하여 얻어진 유리질 비료를 사용하여 작물배지 적합성 및 친환경성을 평가하였다. 용출특성의 경우 유리조성변화를 통하여 장기 및 단기용출이 가능하였으며, 벼에 적응한 결과 생육, 수량은 대조구와 유사하였으며, 식미치의 경우 보다 우수하였다. 또한, 용탈수 분석으로부터 환경친화적 유리질 비료로서의 가능성을 보였다.

Importance of Imidazolidinone Motif in 4-Phenyl-N-arylsulfonylimidazolidinone for their Anticancer Activity

Sharma, Vinay K.,Lee, Ki-Cheul,Joo, Cheon-Ik,Sharma, Niti,Jung, Sang-Hun Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.suppl8

To investigate the possible isosteric replacement of imidazolidinone moiety in 4-phenyl-N-arylsulfonylimidazolidinone for broad and potent anticancer agents, a series of 4-phenyl-l(N)-arylsulfonylimidazolidinones 6a-k, imidazolidinethione analogs 7a-i, and imidazolidine oxime analogs 8a-c were prepared and evaluated for their in vitro anticancer activity against four human cancer cell lines (human lung A549, human colon COLO205, human leukemia K562, human ovary SK-OV-3). Among all the derivatives of N-arylsulfonylimidazolidinone 6a-k, compounds 6f and 6g showed the best inhibition comparable to doxorubicin against all cancer cell lines. Increasing the carbon chain on alkyl moieties of carbamates as shown in 6c-g did not alter the activity. The imidazolidinethione analogs 7a-i and imidazolidin-2-one oxime derivatives 8a-c did not possess any good activity. Therefore, imidazolidinone moiety is the best pharmacophore among the 4-phenyl-Narylsulfonylimidazolidinone derivatives.

소듐고속로 핵연료집합체 측면 오리피스 주입구 난류유동의 전산유체역학 해석

인왕기(W. K. In),정영신(Y. S. Jeong,),이찬(C. Lee),신창환(C. H. Shin),오동석(D. S. Oh),전태현(T. H. Chun),천진식(J. S. Cheon) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11

A liquid sodium is used as coolant in sodium fast reactor(SFR). The reactor coolant pump supplies sodium coolant into a fuel assembly through the inlet chamber with a side orifice. Nine(9) orifices are used in the inlet chamber in three longitudinal and azimuthal directions. This CFD study investigates turbulent flow structure in the inlet chamber and estimate the pressure loss coefficient at the side orifice. The Reynolds number for this CFD simulation is 104, 105 and 2x105 based on the hydraulic diameter and bulk velocity in the orifice. Turbulence models used are the standard k-ε model, SAS-SST model, SSG Reynolds stress model and Large Eddy Simulation(LES). A unsteady flow simulation was performed to more accurately analyze the complex turbulent flow in the inlet chamber with the 9 side orifices. This paper presents the CFD predictions of turbulent flow distribution in the inlet chamber of SFR fuel assembly and the loss coefficient of side orifice.

Simultaneous integration of multiple genes into the Kluyveromyces marxianus chromosome

Heo, P.,Yang, T.J.,Chung, S.C.,Cheon, Y.,Kim, J.S.,Park, J.B.,Koo, H.M.,Cho, K.M.,Seo, J.H.,Park, J.C.,Kweon, D.H. Elsevier Science Publishers 2013 Journal of biotechnology Vol.167 No.3

While Kluyveromyces marxianus is a promising yeast strain for biotechnological applications, genetic engineering of this strain is still challenging, especially when multiple genes are to be transformed. Sequential gene integration, which takes advantage of repetitive insertion/excision of the URA3 gene as a marker, has been the best option until now, because the URA3-deletion mutant is the only precondition for this method. However, we found that the introduced gene is co-excised during the URA3 excision step for next gene introduction, resulting in a very low cumulative probability (<1.57x10<SUP>-6</SUP>% for 4 genes) of integrating all genes of interest. To overcome this extremely low probability, and to reduce labor and time, all 4 genes were simultaneously transformed. Surprisingly, the infamously high 'non-homologous end joining' activity of K. marxianus enabled simultaneous integration of all 4 genes in a single step, with a probability of 7.9%. Various K. marxianus strains could also be similarly transformed. Our finding not only reduces the labor and time required for such procedures, but also removes a number of preconditions, such as pre-made vectors, selection markers and knockout mutants, which are needed to introduce many genes into K. marxianus.

수요자 참여형으로 육성된 최고품질 벼 ‘알찬미’

현웅조(Ung-Jo Hyun),원용재(Yong-Jae Won),정응기(Eung-Gi Jeong),안억근(Eok-Keun Ahn),이정희(Jeong-Heui Lee),정국현(Kuk-Hyun Jung),박향미(Hyang-Mi Park),전용희(Yong-Hee Jeon),곽지은(Jieun Kwak),성낙식(Nak-Sig Sung),김정천(Jeong-Cheon K 한국육종학회 2021 한국육종학회지 Vol.53 No.2

Alchanmi’, a japonica rice variety, was developed from a cross between ‘Junam’ and ‘Chilbo’ by a rice breeding team at the NationalInstitute of Crop Science and Icheon, Agricultural Technology Center in 2018. The heading date of ‘Alchanmi’ was August 10 in the middleplain area-two days later than that of ‘Hwaseong’. ‘Alchanmi’ had a culm length of 69 cm, 16 cm shorter than that of ‘Hwaseong’, and 103spikelets per panicle. The viviparous germination rate of ‘Alchanmi’ was 24.4%. It showed resistance to blast, bacterial blight (K1, K2, K3race), and stripe virus, but was susceptible to the K3a race of bacterial blight, dwarf and black streak dwarf viruses, and plant hoppers. Themilled rice of this variety exhibited a translucent and medium short grain shape. The cooked rice grains of ‘Alchanmi’ had an excellent palatabilityindex (0.7) and showed lower amylose content (18.6%) than that of ‘Hwaseong’. The grain milling characteristics of ‘Alchanmi’ were betterthan those of ‘Hwaseong’, especially the head rice milling recovery ratio and head rice ratio (96.2%). ‘Alchanmi’ showed 5.83 MT/ha of milledrice productivity at 6 sites under ordinary cultivation (Registration No. 8132).

Design and Fabrication of Hexadecagon Type Ultrasonic Motor

Cheon, S.-K.,Jeong, S.-S.,Kim, N.-L.,Kim, M.-H.,Park, T.G. Taylor Francis 2014 Ferroelectrics Vol.459 No.-

<P>Ultrasonic rotary motor which has hexadecagon shape stator was proposed. Stator of the hexadecagon ultrasonic motor was composed of an elastic ring and ceramics. The elastic ring had sixteen sides and sixteen angular points. Eight ceramics were attached on the outer surface of the eight sides of the ring. When two sinusoidal voltages which have 90 degree phase difference were applied to each four ceramics, elliptical displacements of inner surface of the ring were obtained. These elliptical displacements of the inner surface rotated the shaft rotor through the frictions. The proposed hexadecagon ultrasonic motor was designed and analyzed by using the finite element method (FEM). Based on the FEM results, the rotational speed of the fabricated motor was measured by changing the driving frequency and voltage. As FEM results, large displacements at contact points of the stator could be obtained from thinner elastic ring and also thinner ceramics. Rotational speed of 61 [rpm] was obtained from the fabricated motor by applying 10 [V] of alternating voltages.</P>