Combining metabolic engineering and biocompatible chemistry for high-yield production of homo-diacetyl and homo-(S,S)-2,3-butanediol

Liu, J.,Chan, S.H.J.,Brock-Nannestad, T.,Chen, J.,Lee, S.Y.,Solem, C.,Jensen, P.R. Academic Press 2016 Metabolic engineering Vol.36 No.-

Biocompatible chemistry is gaining increasing attention because of its potential within biotechnology for expanding the repertoire of biological transformations carried out by enzymes. Here we demonstrate how biocompatible chemistry can be used for synthesizing valuable compounds as well as for linking metabolic pathways to achieve redox balance and rescued growth. By comprehensive rerouting of metabolism, activation of respiration, and finally metal ion catalysis, we successfully managed to convert the homolactic bacterium Lactococcus lactis into a homo-diacetyl producer with high titer (95mM or 8.2g/L) and high yield (87% of the theoretical maximum). Subsequently, the pathway was extended to (S,S)-2,3-butanediol (S-BDO) through efficiently linking two metabolic pathways via chemical catalysis. This resulted in efficient homo-S-BDO production with a titer of 74mM (6.7g/L) S-BDO and a yield of 82%. The diacetyl and S-BDO production rates and yields obtained are the highest ever reported, demonstrating the promising combination of metabolic engineering and biocompatible chemistry as well as the great potential of L. lactis as a new production platform.

Ultrahigh Vacuum Technologies Developed for a Large Aluminum Accelerator Vacuum System

G. Y. Hsiung,C. C. Chang,Y. C. Yang,C.H. Chang,H. P. Hsueh,S. N. Hsu,J. R. Chen 한국진공학회 2014 Applied Science and Convergence Technology Vol.23 No.6

A large particle accelerator requires an ultrahigh vacuum (UHV) system of average pressureunder 1×10-7 Pa for mitigating the impact of beam scattering from the residual gas molecules. The surface inside the beam ducts should be controlled with an extremely low thermaloutgassing rate under 1×10-9 Pa.m3/(s.m2) for the sake of the insufficient pumping speed. To fulfil the requirements, the aluminum alloys were adopted as the materials of the beamducts for large accelerator that thanks to the good features of higher thermal conductivity,non-radioactivity, non-magnetism, precise machining capability, et al. To put the aluminuminto the large accelerator vacuum systems, several key technologies have been developedwill be introduced. The concepts contain the precise computer numerical control (CNC)machining process for the large aluminum ducts and parts in pure alcohol and in an oil-freeenvironment, surface cleaning with ozonized water, stringent welding process control manuallyor automatically to form a large sector of aluminum ducts, ex-situ baking process to reachUHV and sealed for transportation and installation, UHV pumping with the sputtering ionpumps and the non-evaporable getters (NEG), et al. The developed UHV technologies havebeen applied to the 3 GeV Taiwan Photon Source (TPS) and revealed good results as theexpectation. The problems of leakage encountered during the assembling were most associatedwith the vacuum baking which result in the consequent trouble shootings and more timesof baking. Then the installation of the well-sealed UHV systems is recommended.

Two S-wave gap symmetry for single crystals of the superconductor BaFe_1.8Co_0.2As₂

Choi, K.Y.,Kim, S.H.,Choi, C.,Jung, M.H.,Wang, X.F.,Chen, X.H.,Noh, J.D.,Lee, S.I. North-Holland 2010 Physica. C, Superconductivity Vol.470 No.suppl1

To clarify the gap structure of the iron-pnictide superconductors, we synthesized optimally doped single crystals of BaFe<SUB>1.8</SUB>Co<SUB>0.2</SUB>As<SUB>2</SUB>, which had a critical temperature, T<SUB>c</SUB>, of 23.6K. The initial M-H curve was used to find the lower critical field, H<SUB>c1</SUB>. The full range of the temperature dependence of H<SUB>c1</SUB> was explained by using a two S-wave gap symmetry. We estimate the two gap as Δ<SUB>1</SUB>(0)=1.64+/-0.2meV for the small gap and Δ<SUB>2</SUB>(0)=6.20+/-0.2meV for the large gap.

간호대생과 비보건계열 여대생의 미세먼지 위험에 대한 인식과 지식, 건강 관리행위 비교 연구

김선미,김슬기,김진선,박주형,배다희,유수빈,유영주,임지향,최유진,Chen Mengyao,양숙자,손지희 이화여자대학교 간호과학대학 2019 이화간호학회지 Vol.- No.53

Purpose: This study aimed to know whether there is a comparison of perception, knowledge and health promoting behaviors about particular matter between nursing students and non-health departments college students. Methods: A quantitative research is used. Data were collected from August 1 to 19. The study sample was nursing students and non-health departments students. For the similar condition of samples, this study excluded whose first language is not Korean. Independent T-test and pearson’s correlation was used for this study. Results: A significant positive correlation did not existed between difference of major and perception(t=0.017, p=0.986), knwledge(t=0.652, p=.516) and health promoting behaviors(t=-0.114, p=.910) about particular matters. Conclusion: Based on the study results, there is no significant correlation of perception and actions about particular matters between nursing students and non-health department college students.

Response of plasma rotation to resonant magnetic perturbations in J-TEXT tokamak

Yan, W,Chen, Z Y,Huang, D W,Hu, Q M,Shi, Y J,Ding, Y H,Cheng, Z F,Yang, Z J,Pan, X M,Lee, S G,Tong, R H,Wei, Y N,Dong, Y B IOP 2018 Plasma physics and controlled fusion Vol.60 No.3

<P>The response of plasma toroidal rotation to the external resonant magnetic perturbations (RMP) has been investigated in Joint Texas Experimental Tokamak (J-TEXT) ohmic heating plasmas. For the J-TEXT’s plasmas without the application of RMP, the core toroidal rotation is in the counter-current direction while the edge rotation is near zero or slightly in the co-current direction. Both static RMP experiments and rotating RMP experiments have been applied to investigate the plasma toroidal rotation. The core toroidal rotation decreases to lower level with static RMP. At the same time, the edge rotation can spin to more than 20 km s<SUP>−1</SUP> in co-current direction. On the other hand, the core plasma rotation can be slowed down or be accelerated with the rotating RMP. When the rotating RMP frequency is higher than mode frequency, the plasma rotation can be accelerated to the rotating RMP frequency. The plasma confinement is improved with high frequency rotating RMP. The plasma rotation is decelerated to the rotating RMP frequency when the rotating RMP frequency is lower than the mode frequency. The plasma confinement also degrades with low frequency rotating RMP.</P>

Ultrahigh Vacuum Technologies Developed for a Large Aluminum Accelerator Vacuum System

Hsiung, G.Y.,Chang, C.C.,Yang, Y.C.,Chang, C.H.,Hsueh, H.P.,Hsu, S.N.,Chen, J.R. The Korean Vacuum Society 2014 Applied Science and Convergence Technology Vol.23 No.6

A large particle accelerator requires an ultrahigh vacuum (UHV) system of average pressure under $1{\times}10^{-7}$ Pa for mitigating the impact of beam scattering from the residual gas molecules. The surface inside the beam ducts should be controlled with an extremely low thermal outgassing rate under $1{\times}10^{-9}Pa{\cdot}m^3/(s{\cdot}m^2)$ for the sake of the insufficient pumping speed. To fulfil the requirements, the aluminum alloys were adopted as the materials of the beam ducts for large accelerator that thanks to the good features of higher thermal conductivity, non-radioactivity, non-magnetism, precise machining capability, et al. To put the aluminum into the large accelerator vacuum systems, several key technologies have been developed will be introduced. The concepts contain the precise computer numerical control (CNC) machining process for the large aluminum ducts and parts in pure alcohol and in an oil-free environment, surface cleaning with ozonized water, stringent welding process control manually or automatically to form a large sector of aluminum ducts, ex-situ baking process to reach UHV and sealed for transportation and installation, UHV pumping with the sputtering ion pumps and the non-evaporable getters (NEG), et al. The developed UHV technologies have been applied to the 3 GeV Taiwan Photon Source (TPS) and revealed good results as the expectation. The problems of leakage encountered during the assembling were most associated with the vacuum baking which result in the consequent trouble shootings and more times of baking. Then the installation of the well-sealed UHV systems is recommended.

The Expression of Porcine Adiponectin and Stearoyl Coenzyme a Desaturase Genes in Differentiating Adipocytes

Wang, P.H.,Ko, Y.H.,Liu, B.H.,Peng, H.M.,Lee, M.Y.,Chen, C.Y.,Li, Y.C.,Ding, S.T. Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.5

The gene expression of porcine adiponectin and stearoyl coenzyme A desaturase (SCD) was investigated in this study. The partial gene sequences for adiponectin and SCD were amplified by RT-PCR from subcutaneous adipose tissue and cloned by TA cloning techniques. Sequences of these genes were determined and found to be highly homologous to that of other species, suggesting similar function of these genes as in other species. The transcripts of these adipocyte-related genes in pig tissues were measured by Northern analysis. The transcripts for adiponectin and SCD were highly expressed in porcine subcutaneous adipose tissue; the transcripts for SCD were also barely detected in the liver, but the greatest concentrations were in the adipose tissue. In porcine stromalvascular cells (S/V cells) cultured in vitro, transcripts for adiponectin and SCD increased gradually during adipocyte differentiation. The level of adipocyte adiponectin mRNA was associated with late adipocyte differentiation, indicating the gene may not be involved in adipocyte differentiation but has great importance in porcine adipocyte functions. The SCD transcripts were not detectable until 2 d after induction of adipocyte differentiation. It was highly expressed in differentiating porcine adipocytes (2 to 10 d after the induction of adipocyte differentiation), indicating a significant role of SCD in adipocytes.

1997~2000년에 관측된 황사의 농도와 부하량 및 시정 : 위성과 기상 분석 Satellite and Meteorological Analysis

정용승,김학성,박기현,전종갑,첸수젠 한국교원대학교 환경과학연구소 2001 환경연구논문집 Vol.- No.6

This Korea-China study was to monitor the phenomena of yellow sand(YS) occurred during the period of 1997~2000. The analysis on observed data included ground measurements of dust concentration, visibility, satellite imagery, aircraft and lidar observations. In addition, an estimation of atmospheric loadings and study on the relationship between dust concentrations and visibility were carried out. The movement and invasion of YS clouds to Korea were clearly identified with meterological and satellite data. The increasing concentrations of TSP and PM10 agreed well with the satellite information. We define the YS episode with the following values: TSP ≥250, PM10 ≥190 ㎍m-3, and visibility 6.5 km or less. From case studies, we estimated that atmospheric loadings of a dust cloud were over 1 million ton and that the deposition over the Korean Peninsula was in the range of 46,000 and 86,000 ton. For the YS with visibility 3 km, we predict TSP 659 ㎍m-3, PM10 493 ㎍m-3. We recommend the issuance of the YS Watch (advisory) and the YS Warning for the general public. There is a need for the general use of dust collectors in the indoor environment to reduce YS concentrations in spring.

Individual-breed Assignment Analysis in Swine Populations by Using Microsatellite Markers

Fan, B.,Chen, Y.Z.,Moran, C.,Zhao, S.H,Liu, B.,Yu, M.,Zhu, M.J.,Xiong, T.A.,Li, K. Asian Australasian Association of Animal Productio 2005 Animal Bioscience Vol.18 No.11

Individual-breed assignments were implemented in six swine populations using twenty six microsatellites recommended by the Food and Agriculture Organization and the International Society for Animal Genetics (FAO-ISAG). Most microsatellites exhibited high polymorphisms as shown by the number of alleles and the polymorphism information content. The assignment accuracy per locus obtained by using the Bayesian method ranged from 33.33% (CGA) to 68.47% (S0068), and the accumulated assignment accuracy of the top ten loci combination added up to 96.40%. The assignment power of microsatellites based on the Bayesian method had positive correlations with the number of alleles and the gene differential coefficient ($G_{st}$) per locus, while it has no relationship to genetic heterozygosity, polymorphism information content per locus and the exclusion probabilities under case II and case III. The percentage of corrected assignment was highest for the Bayesian method, followed by the gene frequency and distancebased methods. The assignment efficiency of microsatellites rose with increase in the number of loci used, and it can reach 98% when using a ten-locus combination. This indicated that such a set of ten microsatellites is sufficient for breed verification purposes.

Genetic polymorphism in pvmdr1 and pvcrt-o genes in relation to in vitro drug susceptibility of Plasmodium vivax isolates from malaria-endemic countries

Lu, F.,Lim, C.S.,Nam, D.H.,Kim, K.,Lin, K.,Kim, T.S.,Lee, H.W.,Chen, J.H.,Wang, Y.,Sattabongkot, J.,Han, E.T. Verlag für Recht und Gesellschaft ; Elsevier 2011 Acta Tropica Vol.117 No.2

Treatment failure of chloroquine for Plasmodium vivax infection has increased in endemic countries. However, the molecular mechanisms for resistance and in vitro susceptibility of P. vivax to chloroquine remain elusive. We investigated the prevalence of mutations in the pvmdr1 and pvcrt-o genes, and the copy number of the pvmdr1 gene in isolates from the Republic of Korea (ROK), Thailand, the Union of Myanmar (Myanmar), and Papua New Guinea (PNG). We also measured in vitro susceptibility of Korean isolates to antimalarial drugs. The pvmdr1 analysis showed that mutations at amino acid position Y976F of pvmdr1 were found in isolates from Thailand (17.9%), Myanmar (13.3%), and PNG (100%), but none from the ROK, and mutation at position F1076L was present in isolates from the ROK (100%), Thailand (60.7%), and Myanmar (46.7%). One copy of the pvmdr1 gene was observed in most isolates and double copy numbers of the gene were observed in two Thai isolates. In the exons of the pvcrt-o gene that were sequenced, a K10 insertion was present in isolates from Thailand (56.0%) and Myanmar (46.2%), and the wild type was found in all Korean isolates. The results suggest that gene polymorphisms and copy number variation was observed in isolates of P. vivax from Southeast Asian countries. In Korean isolates polymorphism as limited to the F1076L variant, and no isolates with high level of resistance were found by in vitro susceptibility determinations. Moreover, our results provide a baseline for future prospective drug studies in malaria-endemic areas.