http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Experimental behaviour of composite beams subjected to a hogging moment
Marisa Pecce,Fernando Rossi,Fabio Antonio Bibbò,Francesca Ceroni 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.12 No.5
The present work addresses the rotational capacity of steel-concrete composite beams, which is a key issue for the seismic design of composite frames. Several experimental tests from the literature are summarised, and the effects of various parameters on the available plastic rotation are discussed. Furthermore, a number of remarks are made regarding the need for supplementary experimental results. The authors carried out experimental tests on four composite beams in which the type, width and connection degree of the slab were varied. During the tests, the deflection and strains in the steel profiles and bars were measured and recorded, wherein the observed trends in the measured parameters indicated that the failure mode of the beam was influenced by global and local buckling. A comparison of the experimental results to the theoretical ultimate strengths and moment-curvature relationships confirms that buckling phenomena occurred after section yielding, even if a consistent plastic rotation developed. This rotational capacity is well evaluated by a formulation that is available in the literature.
Morphological Characterization of Normal Human Oral Keratinocytes during Serial Subculture
Bibb, Carol A.,Kang, Mo K.,Park, No-Hee Korean Academy of Oral Biology and the UCLA Dental 1999 International Journal of Oral Biology Vol.24 No.3
This study described the morphology of normal human oral keratinocytes (NHOK) at different phases of an in vitro model of cell aging using phase contrast and electron microscopy. During serial subculture in low clacium conditions, NHOK proliferated exponentially, then entered replicative senesence, producing a prolferation curve with three phases: exponential, senescing, and senescent. Under phase contrase microscopy exponential phase NHOK were small and polygonal in shape with large nuclei containing prominent nucleoli while senescent phase cells were larger overall and contained clear, round, vacuolated spaces in the perinuclear cytoplasm. A better understanding of the cellular morphology was obtained by comparing the ultrastructure of representative cells from the etponential, senescing, and senescent phase of culture. Exponential phase cells had a high nuclear to cytoplasmic ratio, typical housekeeping organelles, and a perinuclear arrangement of keratin bundles. In cells entering esnescence there was a dramatic increase in clear, membrane bound cytoplasmic vacuoles which apperared to coalesce and filled much of the cytoplasmic compartmint in senescent phase cells. The vacuoles, housekeeping organelles, and keratin bundles were in a perinuclear location, leaving a peripheral rim of cytoplasm devoid of structural elements. In cells from all phases, nuclei were intact with diffuse chromatin and prominent nucleoli, although in senescent cells they appeared compressed by the accumulation of vacuoles. Our findings provide morphological evidence that the majority of NHOK in this in vitro model remain viable from exponential growth into senesence. The most notable change in phenotype was an accumulation of cytoplasmic vacuoles in the senescent phase cells.
Conjugal Transfer of Plasmid DNA from Escherichia coli to Streptomyces lavendulae FRI-5
KITANI, SHIGERU,BIBB, MERVYN J.,NIHIRA, TAKUYA,YAMADA, YASUHIRO 한국미생물 · 생명공학회 2000 Journal of microbiology and biotechnology Vol.10 No.4
Streptomyces lavendulae FRI-5 produces the γ-butyrolactone autoregulator IM-2, which is required for nucleoside antibiotic production. We have developed a system for introducing DNA into S. lavendulae FRI-5 via conjugal transfer from Escherichia coli. Conditions were established for conjugation of the oriT- and attP-containing plasmid pSET152 from E. coli ET12567 (pUZ8002) to FRI-5. Conjugation resulted in integration of the plasmid at the chromosomal øC31 attB site. The frequency of intergeneric conjugation varied with the medium used. The highest frequency (1.6×l0^-5 per recipient) was obtained on ISP medium 2 containing 10mM MgCl_2. Southern blot and phenotypic analyses of exconjugants revealed that S. lavendulae FRI-5 contains a unique øC31 attB site, and that integration of heterologous DNA into the attB site did not interfere with morphological differentiation or IM-2-dependent signal transduction, including the production of a blue pigment. This system will now enable detailed genetic analysis of the regulation of antibiotic production in S. lavendulae FRI-5.
Roh, H.,Uguru, G. C.,Ko, H.-J.,Kim, S.,Kim, B.-Y.,Goodfellow, M.,Bull, A. T.,Kim, K. H.,Bibb, M. J.,Choi, I.-G.,Stach, J. E. M. American Society for Microbiology 2011 Journal of Bacteriology Vol.193 No.13
<P>Verrucosispora maris AB-18-032 is a marine actinomycete that produces atrop-abyssomicin C and proximicin A, both of which have novel structures and modes of action. In order to understand the biosynthesis of these compounds, to identify further biosynthetic potential, and to facilitate rational improvement of secondary metabolite titers, we have sequenced the complete 6.7-Mb genome of Verrucosispora maris AB-18-032.</P>