http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Dekun Kong (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
-
-
Lee, Mi-Jin,Kong, Dekun,Han, Kyuboem,Sherman, David H,Bai, Linquan,Deng, Zixin,Lin, Shuangjun,Kim, Eung-Soo Springer International 2012 Applied microbiology and biotechnology Vol.95 No.1
<P>Polyene antibiotics such as nystatin are a large family of very valuable antifungal polyketide compounds typically produced by soil actinomycetes. Previously, using a polyene cytochrome P450 hydroxylase-specific genome screening strategy, Pseudonocardia autotrophica KCTC9441 was determined to contain an approximately 125.7-kb region of contiguous DNA with a total of 23 open reading frames, which are involved in the biosynthesis and regulation of a structurally unique polyene natural product named NPP. Here, we report the complete structure of NPP, which contains an aglycone identical to nystatin and harbors a unique di-sugar moiety, mycosaminyl-(α1-4)-N-acetyl-glucosamine. A mutant generated by inactivation of a sole glycosyltransferase gene (nppDI) within the npp gene cluster can be complemented in trans either by nppDI-encoded protein or by its nystatin counterpart, NysDI, suggesting that the two sugars might be attached by two different glycosyltransferases. Compared with nystatin (which bears a single sugar moiety), the di-sugar containing NPP exhibits approximately 300-fold higher water solubility and 10-fold reduced hemolytic activity, while retaining about 50% antifungal activity against Candida albicans. These characteristics reveal NPP as a promising candidate for further development into a pharmacokinetically improved, less-cytotoxic polyene antifungal antibiotic.</P>
-
Experimental Study on Instant Grouting with Formwork for Tunnels
Zhenliang Zhou,Zhongsheng Tan,Jinpeng Zhao,Zikai Dong,Dekun Kong,Zonglin Li 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.1
Voids between primary support and secondary lining of existing tunnels pose a serious threat to safety and have become a key challenge for tunnel engineering. Due to the poor bonding performance between concrete slurry backfill and lining concrete, the integrity of supporting structures cannot be guaranteed. In recent years, vault grouting with formwork has proved to be effective in solving this problem. However, few studies have focused on the selection of grouting materials and associated grouting process parameters. In this paper, a slight-expanding concrete slurry is selected as the grouting material. The early strength growth trendof the slight-expanding slurry is explored via laboratory tests. The compatibility of the slight-expanding slurry and the lining concrete is analyzed by comparing the slump, expanding diameter, water retention and compressive strength. Bonding-body specimens were fabricated using a mold developed for this work. Furthermore, we compare the compressive strength and failure mode in order to investigate the bonding properties between the sight-expanding slurry and lining concrete at different grouting intervals and pressures. A reasonable set of operational parameters is subsequently proposed. Finally, field tests undertaken in an expressway tunnel in south China are performed in order to determine the impact of grouting with formwork on tunnel lining, while the grouting effect at the vault is evaluated using a ground penetrating radar. The slight-expanding slurry exhibited a high early strength and rapid hardening. Adding slight-expanding slurry to lining concrete at a volume ratio of 1:0.2 increased the slump, diameter and compressive strength by 13.4%, 15.6%, and 25.0%, respectively. When a grouting interval is less than 6 h, the pressure of grouting with formwork should be no less than 0.2 MPa, while for a grouting interval of 8 h, the grouting pressure should be no less than 0.4 MPa. The grouting pressure of 0.4 MPa exerts a limited effect on the existing secondary lining concrete, and the stress increment produced by grouting accounts for 6 − 17% of the total increment. The results presented can provide a reference for future tunnel construction.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
