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Anaerobic Bacterial Degradation for the Effective Utilization of Biomass
Ohmiya, Kunio,Sakka, Kazuo,Kimura, Tetsuya The Korean Society for Biotechnology and Bioengine 2005 Biotechnology and Bioprocess Engineering Vol.10 No.6
Biomass is originally photosynthesized from inorgainic compounds such as $CO_2$, minerals, water and solar energy. Recent studies have shown that anaerobic bacteria have the ability to convert recalcitrant biomass such as cellullosic or chitinoic materials to useful compounds. The biomass containing agricultural waste, unutilized wood and other garbage is expected to utilize as feed, food and fuel by microbial degradation and other metabolic functions. In this study we isolated several anaerobic, cellulolytic and chitinolytic bacteria from rumen fluid, compost and soil to study their related enzymes and genes. The anaerobic and cellulolytic bacteria, Clostridium thermocellum, Clostridium stercorarium, and Clostridium josui, were isolated from compost and the chitinolytic Clostridium paraputrificum from beach soil and Ruminococcus albus was isolated from cow rumen. After isolation, novel cellulase and xylanase genes from these anaerobes were cloned and expressed in Escherichia coli. The properties of the cloned enzymes showed that some of them were the components of the enzyme (cellulase) complex, i.e., cellulosome, which is known to form complexes by binding cohesin domains on the cellulase integrating protein (Cip: or core protein) and dockerin domains on the enzymes. Several dockerin and cohesin polypeptides were independently produced by E. coli and their binding properties were specified with BIAcore by measuring surface plasmon resonance. Three pairs of cohesin-dockerin with differing binding specificities were selected. Two of their genes encoding their respective cohesin polypeptides were combined to one gene and expressed in E. coli as a chimeric core protein, on which two dockerin-dehydrogenase chimeras, the dockerin-formaldehyde dehydrogenase and the dockerin-NADH dehydrogenase are planning to bind for catalyzing $CO_2$ reduction to formic acid by feeding NADH. This reaction may represent a novel strategy for the reduction of the green house gases. Enzymes from the anaerobes were also expressed in tobacco and rice plants. The activity of a xylanase from C. stercorarium was detected in leaves, stems, and rice grain under the control of CaMV35S promoter. The digestibility of transgenic rice leaves in goat rumen was slightly accelerated. C. paraputrificum was found to solubilize shrimp shells and chitin to generate hydrogen gas. Hydrogen productivity (1.7 mol $H_2/mol$ glucos) of the organism was improved up to 1.8 times by additional expression of the own hydrogenase gene in C. paraputrficum using a modified vector of Clostridiu, perfringens. The hydrygen producing microflora from soil, garbage and dried pelletted garbage, known as refuse derived fuel(RDF), were also found to be effective in converting biomass waste to hydrogen gas.
유용호,박계원,Yoshifumi Ohmiya 한국방재학회 2015 한국방재학회 학술발표대회논문집 Vol.14 No.-
본 연구에서는 부산 해운대 화재사고(2010년)와 같은 고층 건축물 화재시, 외벽 외장재를 통한 수직화재확산 피해를 저감시키기 위하여 도입이 검토 되고 있는 실대형 시험법의 교정 절차에 대한 연구를 수행하였다. 이를 위하여 일본 동경이과대학 화재과학연구실의 외장재 시험장치를 이용한 교정시험을 실시하였으며, 화원으로는 도시가스를 사용한 경우와 대체화원인 목재클립을 적재한 화원 각 2경우에 대하여 시험을 실시하였다. 측정항목은 각각의 경우에 대하여 열류량과 온도를 측정하였다. 교정시험결과 두 경우 모두 표준시험법에서 제시하고 있는 열류량 기준(55 kw/m2)보다 3배가량 높은 150 kw/m2 측정되었으며, 온도 기준(800 ℃) 역시 1,000℃ 상회하는 결과를 나타내었다. 이는 표준시험법에서 가스의 공급량만을 규정하고 있을 뿐 공기 공급량 및 실험시 후드의 높이 그리고 주변 기류 조건등 기타 조건에 대한 명확한 세부 조건이 제시하지 않아 생기는 문제로 분석된다. 따라서, 이로 인한 균일한 화재조건 구현이 이루어지 어려울 것으로 판단되며, 특히 외장재의 수직화재확산 정도를 평가하기에는 너무도 가혹한 화재조건인 것으로 평가되었다. 본 실험을 통하여 표준시험법의 보다 명확한 화재원 확립 및 교정 시험 절차 개정을 위한 기초 자료를 수집하였으며, 이를 토대로 한 개정 심의 활동이 전개되어야 할 것으로 평가 되었다.
Effect of aggregate on residual mechanical properties of heated ultra-high-strength concrete
Kim, Y. S.,Ohmiya, Y.,Kanematsu, M.,Kim, G. Y. Rilem Publications 2016 Materials and Structures Vol.49 No.9
<P>When concrete structures are exposed to fire temperatures, their internal structure will change, and then the service life of the structure will decrease due to the deterioration of its strength and deformation capacity. The deterioration level will depend on the temperature reached, exposure time, mix proportions of the concrete, aggregate property and the material's own characteristics. This study was carried out to evaluate the influence of water to cement ratio, fine-grained aggregate to aggregate ratio and maximum size of aggregate on the thermal behavior of ultra-high-strength concrete. At room temperature and 500 degrees C the tests for compressive strength, static modulus of elasticity, ultrasonic pulse velocity, dynamic modulus of elasticity and weight loss were measured using the cylindrical specimens of empty set100 9 200 mm. The test data indicated that the fine-grained aggregate to aggregate ratio and the maximum size of aggregate have a significant influence on the residual mechanical properties of ultra-high strength concrete. And by measuring the ultrasonic pulse velocity of the ultra-high-strength concrete specimens, it was confirmed in this study that predicting the residual compressive strength is a distinct possibility.</P>
Polyelectrolyte Hydrogels for Replacement and Regeneration of Biological Tissues
권혁준,Kazunori Yasuda,Jian Ping Gong,Yoshihiro Ohmiya 한국고분자학회 2014 Macromolecular Research Vol.22 No.3
Polyelectrolyte gels are charged polymer networks with macro-ions fixed on the polymer chains. Thesegels have considerable potential for biological applications such as cellular scaffolds and the replacement of variousbiological tissues. Moreover, high strength up to several tens of megapascals can be obtained with polyelectrolytegels by incorporating double network structure in the gel. This article gives a concise review to introduce thefundamental properties of polyelectrolyte gels and biological applications for tissue engineering using theircharacteristic properties. Applications of polyelectrolyte gels have been highlighted in the fields of artificial muscle,artificial corneas, artificial cartilage, scaffolds for in vitro stem cell culture, and scaffolds for in vivo cartilage regeneration. This review suggests that polyelectrolyte gels would be a useful material for the successful replacement and regenerationof damaged or diseased tissues.
Coactivation of the CLOCK-BMAL1 complex by CBP mediates resetting of the circadian clock.
Lee, Yool,Lee, Jiwon,Kwon, Ilmin,Nakajima, Yoshihiro,Ohmiya, Yoshihiro,Son, Gi Hoon,Lee, Kun Ho,Kim, Kyungjin Cambridge University Press 2010 Journal of cell science Vol.123 No.20
<P>The transcription factor CLOCK-BMAL1 is a core component of the molecular clock machinery that drives circadian gene expression and physiology in mammals. Recently, we reported that this heterodimeric transcription factor functions as a signaling molecule in response to the resetting stimuli via the Ca²+-dependent protein kinase C pathway. Here, we demonstrate that the CREB-binding protein (CBP) plays a key role in rapid activation of the CLOCK-BMAL1 heterodimer that leads to phase resetting of the circadian clock. Under physiological conditions, a bimolecular fluorescence complementation (BiFC) assay revealed that CLOCK and BMAL1 dimerize in the cytoplasm and subsequently translocate into the nucleus in response to serum stimuli (mean time duration was 29.2 minutes and mean velocity 0.7 관m/minute). Concomitantly, BMAL1 rapidly recruited CBP on Per1 promoter E-box, but not p300 (a functional analog of CBP), in the discrete nuclear foci. However, recruitment of CBP by cAMP/Ca²+ response element-binding (CREB) protein on CRE was not markedly increased upon delivery of the resetting stimuli. Furthermore, overexpression of CBP greatly potentiated the CLOCK-BMAL1-mediated Per1 transcription, and this effect was completely abolished by site-directed mutation of E-box elements, but not by the mutation of CRE in the Per1 promoter. Furthermore, molecular knockdown of CBP severely dampened circadian oscillation of clock gene expression triggered by the resetting stimuli. These findings suggest that CBP recruitment by BMAL1 mediates acute transactivation of CLOCK-BMAL1, thereby inducing immediate-early Per1 transcription and phase resetting of the circadian clock.</P>