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81.
Heung-Jin Choi Dong-Hee Lee Yeon Sil Park In-Kyu Lee Young-Chul Kim 《Journal of inclusion phenomena and macrocyclic chemistry》2002,43(1-2):15-18
Octahedrally converging hexadentate macrocyclic receptors 1 and 2, based on L-tartaric acid and furanmoieties, were synthesized andtheir complexation properties studied. In this paper,magnesium ion selectivitiesdetermined by ISE experiments, chiroptical changes observedby circular dichroism(CD) on complexation, and association constants measuredby NMR titration arediscussed. 相似文献
82.
Jeong Gwi-Taek Park Don-Hee Hwang Baik Park Kyungmoon Kim Si-Wouk Woo Je-Chang 《Applied biochemistry and biotechnology》2002,98(1-9):1115-1127
The growth properties of Panax ginseng hairy roots transformed by Agrobacterium rhizogenes were compared between flask and aerated column or stirred bioreactor. In flask cultures, sucrose, initially 30 g/L, was nearly
exhausted after 45 d of culture. The pH of the medium dropped from 5.5 to 4.96 after 10 d, but afterward it gradually increased
to 6.4. After 45 d, hairy roots grew about 16-folds. The growth rate of hairy roots in air-bubble column or stirred bioreactor
cultures was 1.13 (1.11) to 1.23 (1.20) g fresh wt (dry wt)/(g of cells·d), respectively. For both bioreactors, growth was
about three times as high as in the flask cultivation. 相似文献
83.
Dorothy J. Park Tammy D. Fulmer Charles F. Beam 《Journal of heterocyclic chemistry》1981,18(3):649-651
C(α),O-Dilithiooximes were prepared in an excess of lithium diisopropylamide and condensed with several 2-aminobenzophenones, followed by acid hydrolysis of the oximes to the ketones, which then underwent cyclodehydration and linear dehydration to give substituted quinolines or dihydrobenz[c]acridines. 相似文献
84.
Tae Oan Ahn Jung Ho Kim Jong Chan Lee Han Mo Jeong Jong-Yoon Park 《Journal of polymer science. Part A, Polymer chemistry》1993,31(2):435-441
A macro-azoinitiator containing polyarylate segment and azo group was prepared by the solution polycondensation of azobiscyanopentanoyl chloride and hydroxy-terminated polyarylates having viscosity-average molecular weights of 6200, 8100, and 12 400. These macro-azoinitiators were used in the radical polymerization of styrene to synthesize polyarylate-polystyrene block copolymers. Thermal properties measured by the differential scanning calorimetry indicated the phase separated morphology of the block copolymers except at low molecular weight of the block constituents. © 1993 John Wiley & Sons, Inc. 相似文献
85.
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88.
Determination of sulfite in Oriental herbal medicines 总被引:4,自引:0,他引:4
Kim YK Koh E Park SY Chang SY Park SJ Na WI Kim HJ 《Journal of AOAC International》2000,83(5):1149-1154
Sulfite was detected in 7 varieties of Oriental herbal medicines (Pueraria radix, Zingiberis rhizoma, Platycodon radix, Adenophora radix, Pinellia tuber, Astragalus radix, and Paeonia radix) on the Korean market. Sulfiting of commercial Oriental herbal medicines by fumigation with burning bituminous coal was simulated, and the accumulation of sulfite was investigated by using fresh Platycodon radix roots obtained from a growing field. The sulfite level reached a plateau in 9 h, and the maximum sulfite level found by the Monier-Williams (MW) method (AOAC 990.28) was 1020 ppm. The sulfite content in the simulated Platycodon radix sample determined by alkali extraction followed by ion-exclusion chromatography with electrochemical detection (AOAC 990.31) was approximately 17% lower on average than the MW results. Free-sulfite levels determined by acid extraction and ion-exclusion chromatography with electrochemical detection were between 19 and 49% of the MW results. The advantages of different methods for sulfite determination and the significance of the results are discussed. 相似文献
89.
Stamp collapse in soft lithography 总被引:1,自引:0,他引:1
Huang YY Zhou W Hsia KJ Menard E Park JU Rogers JA Alleyne AG 《Langmuir : the ACS journal of surfaces and colloids》2005,21(17):8058-8068
We have studied the so-called roof collapse in soft lithography. Roof collapse is due to the adhesion between the PDMS stamp and substrate, and it may affect the quality of soft lithography. Our analysis accounts for the interactions of multiple punches and the effect of elastic mismatch between the PDMS stamp and substrate. A scaling law among the stamp modulus, punch height and spacing, and work of adhesion between the stamp and substrate is established. Such a scaling law leads to a simple criterion against the unwanted roof collapse. The present study agrees well with the experimental data. 相似文献
90.
Biosynthesis of polyhydroxyalkanoates (PHAs) consisting of 3-hydroxyalkanoates (3HAs) of 4 to 10 carbon atoms was examined
in metabolically engineered Escherichia coli strains. When the fadA and/or fadB mutant E. coli strains harboring the plasmid containing the Pseudomonas sp. 61-3 phaC2 gene and the Ralstonia eutropha phaAB genes were cultured in Luria-Bertani (LB) medium supplemented with 2 g/L of sodium decanoate, all the recombinant E. coli strains synthesized PHAs consisting of C4, C6, C8, and C10 monomer units. The monomer composition of PHA was dependent on
the E. coli strain used. When the fadA mutant E. coli was employed, PHA containing up to 63 mol% of 3-hydroyhexanoate was produced. In fadB and fadAB mutant E. coli strains, 3-hydroxybutyrate (3HB) was efficiently incorporated into PHA up to 86 mol%. Cultivation of recombinant fadA and/or fadB mutant E. coli strains in LB medium containing 10 g/L of sodium gluconate and 2 g/L of sodium decanoate resulted in the production of PHA
copolymer containing a very high fraction of 3HB up to 95 mol%. Since the material properties of PHA copolymer consisting
of a large fraction of 3HB and a small fraction of medium-chain-length 3HA are similar to those of low-density polyethylene,
recombinant E. coli strains constructed in this study should be useful for the production of PHAs suitable for various commercial applications. 相似文献