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1.
低温脂肪酶产生菌的筛选、鉴定及其部分酶学性质 总被引:15,自引:1,他引:14
从南极乔治王岛冻土来源的76株低温细菌中筛选到13株低温脂肪酶产生菌,对其中的BTsl0022菌株进行鉴定。通过生理生化特征、16s rDNA基因序列的同源性和系统发育分析发现,菌株RTsl0022属于假单胞菌属(Pseudomonas),但与已定名的假单胞菌有一定的差异,与未定名的Pseudomonas sp.PsB的亲缘关系最接近,故将其暂定名为Pseudomonas sp.BTsl0022。对该菌脂肪酶的酶学性质初步研究表明,酶的最适作用温度为24℃,对热敏感,60℃处理30min仅残留25%酶活性,酶的适宜作用pH范围在7.0~9.0,最适pH为8.0。 相似文献
2.
Liang Y.C. Wenjiang Zeng Pick Hong Ong Zhaoxia Gao Jun Cai Balasubramanian N. 《Electron Device Letters, IEEE》2002,23(12):700-703
In this letter, a concise process technology is proposed for the first time to enable the fabrication of good quality three-dimensional (3-D) suspended radio frequency (RF) micro-inductors on bulk silicon, without utilizing the lithography process on sidewall and trench-bottom patterning. Samples were fabricated to demonstrate the applicability of the proposed process technology. 相似文献
3.
Aimin Xiang Zhongjie Du Qinghua Zeng Chen Zhang Hangquan Li 《Polymer International》2005,54(10):1366-1370
This paper presents recent efforts on the preparation of flexible polyhedral particles via concentrated emulsion templating polymerization in which the hydrophilic monomer (acrylamide) and hydrophobic monomer (butyl acrylate) are polymerized simultaneously in the continuous and dispersed phase, respectively. Such templating polymerization has been enhanced in our systems owing to the introduction of acrylamide monomer and their higher polymerization rate in continuous phase as compared with butyl acrylate in dispersed phase. Diffusion between the different phases was also inhibited. Furthermore, the stability of the concentrated emulsion and the molecular weight of the produced poly(butyl acrylate) were found to be significantly affected by the amount of redox initiator. The morphology of the particles could be controlled by varying the volume fraction of the dispersed phase and the polyhedral particles were achieved at higher volume fraction. Copyright © 2005 Society of Chemical Industry 相似文献
4.
5.
Interfacial hybridization kinetics of oligonucleotides immobilized onto fused silica surfaces 总被引:3,自引:0,他引:3
Jiang Zeng Amer Almadidy James Watterson Ulrich J. Krull 《Sensors and actuators. B, Chemical》2003,90(1-3):68-75
Fused silica optical fibers have been used in an intrinsic mode optical configuration as biosensors for fluorescence based detection of hybridization of nucleic acids. In this work, the kinetics of hybridization of single-stranded oligonucleotides that were covalently immobilized were studied. The probe DNA was dT20, and the target was Fluorescein-labeled non-complementary (dT20) or complementary (dA20) oligonucleotide. Chronofluorimetric monitoring of the adsorption and hybridization processes was used to investigate oligonucleotide films of different density, in different salt concentrations, at temperatures of 25 and 40 °C, with the concentration of the target DNA being 0.005–0.1 μM. Mathematical models based on first- and second-order Langmuir adsorption have been examined to describe both the adsorption and the hybridization processes. Experimental data were processed using the models, and the hybridization kinetics were calculated. Hybridization kinetics on these optical fiber DNA sensors was found to be up to three orders faster than results presented for a number of other experiments using different immobilization chemistries. 相似文献
6.
An innovative method for modelling biological processes under anaerobic conditions is presented and discussed. The method is based on titrimetric and off-gas measurements. Titrimetric data is recorded as the addition rate of hydroxyl ions or protons that is required to maintain pH in a bioreactor at a constant level. An off-gas analysis arrangement measures, among other things, the transfer rate of carbon dioxide. The integration of these signals results in a continuous signal which is solely related to the biological reactions. When coupled with a mathematical model of the biological reactions, the signal allows a detailed characterisation of these reactions, which would otherwise be difficult to achieve. Two applications of the method to the enhanced biological phosphorus removal processes are presented and discussed to demonstrate the principle and effectiveness of the method. 相似文献
7.
本文通过对压电量测系统等效电路图的逐步简化,得出矩形脉冲信号的漏电方程;并对系统在各种情况下的时间常数,漏电相对误差进行了计算,最后就系统在校准和现场测试中经常碰到的几种情况,进行了定量估算,从而解决了压电量测系统在使用中的一些具体问题。 相似文献
8.
The present study determined tumorigenicity, tumor classification and DNA damage induced in infant mice by benzo[a]pyrene (B[a]P) or Manufactured Gas Plant (MGP) residues after a single exposure. Male and female B6C3F1 mice were exposed to B[a]P or MGP residue from a single environmental site (MGP-4) and males were also exposed to MGP residue composite from seven different sites (MGP-M7). At 26, 39 and 52 weeks after exposure tumorigenesis was assessed in lung, forestomach and liver. Formation and persistence of DNA adducts were quantified by 32P-postlabeling. Exposure of males to B[a]P induced liver tumors in a dose and time dependent manner. MGP induced more advanced tumors than B[a]P. Only a single liver tumor was found in MGP-4 treated females. No forestomach and few pulmonary adenomas were induced in males or females. MGP-4, MGP-M7 or B[a]P induced DNA adducts in males and females. Adducts in liver, lung and forestomach peaked on different days and decreased at different rates. At 24 h post-exposure, no significant differences in initial DNA adduct levels occurred in males and females exposed to MGP-4 or B[a]P. Lack of DNA damage (adducted DNA) did not account for non-responsiveness of lung and forestomach in B6C3F1 genders as well as in liver in females. MGP tumorigenicity could not be accounted for solely by B[a]P content nor did it reflect additivity of B[a]P and other carcinogenic polycyclic aromatic hydrocarbons (PAHs) in MGP. Synergy among MGP-PAHs, presence of unidentified carcinogens and/or promoters in MGP may account for MGP potency. The B6C3F1 infant male model is a convenient and rapid assay for assessing MGP liver tumorigenicity and potency. 相似文献
9.
10.
Prof. Dipl.-Ing. Dr.techn. Walter Gretler Prof. Dr. Si-min Zeng 《Forschung im Ingenieurwesen》1996,62(5):105-115
A numerical simulation of unsteady compressible flow induced by two high-speed trains in oncoming traffic within a tunnel
is presented. The computations were carried out by means of a second-order accurate Harten-Yee type upwind TVD scheme. In
order to take the effect of friction into account, a source term is included in the governing flow equations. In the computation,
moving boundary configurations were used to simulate the two trains passing through the tunnel. As geometrical configuration,
the Einmalberg tunnel, where experimental data are available, was selected. The computational results agree reasonably well
with their experimental counter-part. The waves interaction and the waves propagation process at the tunnel entrance and exit
as well as within the tunnel are addressed. Finally, the influence on the transmitted waves at the tunnel exit portal and
the variation of the negative pressure drop during the passage of the two trains are discussed. 相似文献