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Formate-driven growth coupled with H<sub>2</sub> production
Kim, Yun Jae,Lee, Hyun Sook,Kim, Eun Sook,Bae, Seung Seob,Lim, Jae Kyu,Matsumi, Rie,Lebedinsky, Alexander V.,Sokolova, Tatyana G.,Kozhevnikova, Darya A.,Cha, Sun-Shin,Kim, Sang-Jin,Kwon, Kae Kyoung,Im Nature Publishing Group, a division of Macmillan P 2010 Nature Vol.467 No.7313
Although a common reaction in anaerobic environments, the conversion of formate and water to bicarbonate and H<SUB>2</SUB> (with a change in Gibbs free energy of ?G째 = +1.3??kJ??mol<SUP>??1</SUP>) has not been considered energetic enough to support growth of microorganisms. Recently, experimental evidence for growth on formate was reported for syntrophic communities of Moorella sp. strain AMP and a hydrogen-consuming Methanothermobacter species and of Desulfovibrio sp. strain G11 and Methanobrevibacter arboriphilus strain AZ. The basis of the sustainable growth of the formate-users is explained by H<SUB>2</SUB> consumption by the methanogens, which lowers the H<SUB>2</SUB> partial pressure, thus making the pathway exergonic. However, it has not been shown that a single strain can grow on formate by catalysing its conversion to bicarbonate and H<SUB>2</SUB>. Here we report that several hyperthermophilic archaea belonging to the Thermococcus genus are capable of formate-oxidizing, H<SUB>2</SUB>-producing growth. The actual ?G values for the formate metabolism are calculated to range between ??8 and ??20??kJ??mol<SUP>??1</SUP> under the physiological conditions where Thermococcus onnurineus strain NA1 are grown. Furthermore, we detected ATP synthesis in the presence of formate as a sole energy source. Gene expression profiling and disruption identified the gene cluster encoding formate hydrogen lyase, cation/proton antiporter and formate transporter, which were responsible for the growth of T. onnurineus NA1 on formate. This work shows formate-driven growth by a single microorganism with protons as the electron acceptor, and reports the biochemical basis of this ability.
위상형 CGH(computer generated hologram)를 이용한 비구면 파면 및 Bessel beam 제작
성기영,경천수,이영락,이정훈,이상조,곽종훈 영남대학교 기초과학연구소 2000 基礎科學硏究 Vol.20 No.-
We have designed and fabricated computer generated holograms(CGH) to generate ashepheric wavefront and Bessel beam. Designed CGH is recorded onto the photopolymer which is used as a volume hologram material mating CGHOE(computer generated holographic optical element). To investigate properties of fabricated CGHOE, intensities of Bessel beam are measured as a function of propagation(z-axis) and transverse (x-axis) distances.
Jaemoon Lee,이동규,Kwon Won-Kyoung,Lee Sookyung,오충식,Görlinger Klaus,김태엽 대한마취통증의학회 2024 Korean Journal of Anesthesiology Vol.77 No.2
Background: Ultrafiltration (UF) would enhance coagulation profiles by concentrating coagulation elements during cardiopulmonary bypass (CPB) for cardiac surgery. Methods: We retrospectively reviewed electronic medical records of 75 patients who had undergone cardiac surgery with rotational thromboelastometry-based coagulation management in a university hospital and analyzed the UF-induced changes in the maximum clot firmness (MCF) of extrinsically activated test with tissue factor (EXTEM) during CPB in 30 patients. Results: The median volume of filtered-free water was 1,350 ml, and median hematocrit was significantly increased from 22.5% to 25.5%. As the primary measure, UF significantly increased the median MCF-EXTEM from 48.0 mm to 50.5 mm (P = 0.015, effect size r = 0.44). The area under the receiver operating characteristic curve pre-UF MCF-EXTEM for discrimination of any increase of MCF-EXTEM after applying UF was 0.89 (95% CI [0.77, 1.00], P < 0.001), and its cut-off value was 50.5 mm (specificity of 81.8% and sensitivity of 84.2% in Youden’s J statistic). In the secondary analyses using the cut-off value, UF significantly increased the median MCF-EXTEM from 40.5 mm to 42.5 mm in 18 patients with pre-UF MCF-EXTEM ≤ 50.5 mm. However, it did not increase MCF-EXTEM in 12 patients with pre-UF MCF-EXTEM > 50.5 mm. There was a significant interaction between pre-UF MCF-EXTEM values and applying UF (P < 0.001 for the subgroup, P = 0.046 for UF, P = 0.003 for interaction).Conclusions: Applying UF improved clot firmness, and the improvement was more pronounced when pre-UF MCF-EXTEM had been reduced during CPB.
포토폴리머-액정 혼합매질의 전기광학 및 홀로그램 기록 특성
경천수, 성기영, 이영락, 최병철, 김태균, 곽종훈 영남대학교 기초과학연구소 2000 基礎科學硏究 Vol.20 No.-
We studied on the electro-optic properties of the photopolymer-liquid crystal composite(polymer-dispersed liquid crystal: PDLC), which has a large refractive index modulation and is controlled by applied AC electric field. The hologram formation kinetics of the HPDLC and also investigated by changing various physical parameters: liquid crystal concentration, grating spacings, and applied fields.
<i>In Vitro</i> Biosynthesis of Metal Nanoparticles in Microdroplets
Lee, Kyoung G.,Hong, Jongin,Wang, Kye Won,Heo, Nam Su,Kim, Do Hyun,Lee, Sang Yup,Lee, Seok Jae,Park, Tae Jung American Chemical Society 2012 ACS NANO Vol.6 No.8
<P>We report the use of a hydrogel polymer, recombinant <I>Escherichia coli</I> cell extracts, and a microdroplet-based microfluidic device to fabricate artificial cellular bioreactors which act as reactors to synthesize diverse metal nanoparticles (NPs). The combination of cell extracts, microdroplet-based microfluidic device, and hydrogel was able to produce a mass amount of artificial cellular bioreactors with uniform size and shape. For the first time, we report the alternating generation of microdroplets through one orifice for the fabrication of the artificial cellular reactors using the cell extract as inner cellular components and hydrogel as an artificial cellular membrane. Notably, the hydrogels were able to protect the encapsulated cell extracts from the surrounding environment and maintain the functionality of cellular component for the further cellular bioreactor applications. Furthermore, the successful applications of the fabricated artificial cellular bioreactors to synthesize various NPs including quantum dots, iron, and gold was demonstrated. By employing this microfluidic technique, the artificial cellular bioreactors could be applicable for the synthesis of diverse metal NPs through simple dipping of the reactors to the metal precursor solutions. Thus, the different size of NPs can be synthesized through controlling the concentration of metal precursors. This artificial cellular bioreactors offer promising abilities to biofriendly ways to synthesis diverse NPs and can be applicable in chemical, biomedical, and bioengineering applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2012/ancac3.2012.6.issue-8/nn302043q/production/images/medium/nn-2012-02043q_0001.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn302043q'>ACS Electronic Supporting Info</A></P>
Lee, Kyoung G,Min, Jung Sun,Wi, Rinbok,Kim, Jin Chul,Ahn, Jeong Keun,Kim, Do Hyun American Scientific Publishers 2011 Journal of Nanoscience and Nanotechnology Vol.11 No.1
<P>Silica nanorods were fabricated with single-walled carbon nanotubes (SWCNTs) via ultrasound. The diameter of the resulting SWCNT-silica particles ranged from 60 to 70 nm. The morphology of this composite material was investigated via scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The individual SWCNTs are uniformly coated with silica and formed a unique nanocomposite material. The important role of ultrasound and the mechanism of silica layer formation on SWCNTs were explained via the hydrolysis of the silica source and the adsorption of the siloxane groups on the SWCNT surfaces under ultrasound irradiation. The amino-functionalized silica nanorods were demonstrated as non-viral vectors for gene delivery.</P>
Lee, Kyoung G.,Park, Tae Jung,Soo, Song Young,Wang, Kye Won,Kim, Byeong I.I.,Park, Jae Hong,Lee, Chang‐,Soo,Kim, Do Hyun,Lee, Seok Jae Wiley Subscription Services, Inc., A Wiley Company 2010 Biotechnology and bioengineering Vol.107 No.4
<P><B>Abstract</B></P><P>We report herein an effective strategy for encapsulating <I>Escherichia coli</I> in polyethylene glycol diacrylate (PEGDA) microdroplets using a microfluidic device and chemical polymerization. PEGDA was employed as a reactant due to the biocompatibility, high porosity, and hydrophilic property. The uniform size and shape of microdroplets are obtained in a single‐step process using microfluidic device. The size of microdroplets can be controlled through the changing continuous flow rate. The combination of microdroplet generation and chemical polymerization techniques provide unique environment to produce non‐toxic ways of fabricating microorganism‐encapsulated hydrogel microbeads. Due to these unique properties of micro‐sized hydrogel microbeads, the encapsulated <I>E. coli</I> can maintain viability inside of microbeads and green fluorescent protein (GFP) and red fluorescent protein (RFP) genes are efficiently expressed inside of microbeads after isopropyl‐<I>β</I>‐<SMALL>D</SMALL>‐thiogalactopyranoside induction, suggesting that there is no low‐molecular weight substrate transfer limitation inside of microbeads. Furthermore, non‐toxic, gentle, and outstanding biocompatibility of microbeads, the encapsulated <I>E. coli</I> can be used in various applications including biotransformation, biosensing, bioremediation, and engineering of artificial cells. Biotechnol. Bioeng. 2010;107:747–751. © 2010 Wiley Periodicals, Inc.</P>
Physical and Adhesive Properties of Cyanoacrylate-Based β-TCP Composites
Lee, G.S.,Lee, Sang Bae,Lee, Doug Youn,Park, Kyeong Jun,Kim, S.O.,Kim, Kyoung Nam,Choi, B.J. Trans Tech Publications, Ltd. 2007 Key engineering materials Vol.330 No.-
<P>Histoacryl® (N-butyl-2-cyanoacrylate) has been widely utilized as a tissue adhesive. The aim of this study was to evaluate the physical and adhesive properties of newly developed cyanoacrylate-based β-TCP composite systems. The β-TCP powder was modified on the surface with citric acid to make this material mixed with cyanoacrylate easily. The setting time of acidtreated β-TCP/ Histoacryl® systems was dramatically prolonged and the polymerization heat was significantly decreased compared to that of untreated β-TCP/Histoacryl® system. The shear bond strength of cyanoacrylate-based β-TCP composites decreased with addition of acid-treated β-TCP filler. The compressive strength of β-TCP/Histoacryl® composites increased strongly with increasing the amount of acid-treated β-TCP filler. The cytotoxicity of the β-TCP/Histoacryl® composites decreased with the increasing of the amount of added β-TCP. These results indicated that our novel β-TCP/Histoacryl® composites had the great potential to serve as adhesives or filling materials in the dental field.</P>