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991.
《European Polymer Journal》2002,38(11):2133-2141
Superswelling acrylamide (AAm)/maleic acid (MA) hydrogels were prepared by free radical polymerization in aqueous solution of AAm with MA as comonomer with some multifunctional crosslinkers such as trimethylolpropane triacrylate and 1,4-butanediol dimethacrylate. AAm/MA hydrogels were used in experiments on swelling and adsorption of a water-soluble monovalent cationic dye such as Basic Blue 17 (Toluidin Blue). As a result of dynamic swelling tests, the influence of relative content of MA on the swelling properties of the hydrogel systems was examined. AAm/MA hydrogels were swollen in the range 1660-6050% in water, while AAm hydrogels swelled in the range 780-1360%. Equilibrium water content of AAm/MA hydrogels were calculated in the range 0.8873-0.9837. Water intake of hydrogels followed a non-Fickian type diffusion. The uptake of the cationic dye, BB-17 to AAm/MA hydrogels is studied by batch adsorption technique at 25 °C. In the experiments of the adsorption equilibrium, S-type adsorption in Giles's classification system was found. The binding ratio of hydrogel/dye systems was gradually increased with the increase of MA content in the AAm/MA hydrogels. 相似文献
992.
The glycosides of volatile compounds and the essential oil were isolated from wild Mentha longifolia. After the enzymatic hydrolysis of glycosides, fourteen volatile aglycones were identified by GC/MS. The main aglycones were eugenol, 2-phenylethanol, benzyl alcohol, lavandulol, trans- and cis-carveol, 3-octanol, and 3-hexen-1-ol. The content of aglycones was 40.85 mg kg-1 of dried plant material. The main components of the essential oil (yield 0.93 w/w) were carvone, piperitenone oxide, limonene, and -caryophyllene. Eugenol, carveol, 3-octanol, and -terpineol were identified in the aglycones and in the essential oil. 相似文献
993.
994.
On a New Copper Cobalt Borate Oxide with Isolated B2O5 Units: Cu2Co(B2O5)O Single crystals of a new compound with the empirical formula Cu2CoB2O6 were obtained by using a B2O3 flux technique. X-ray single crystal technique led to a new structure type. Cu2CoB2O6 crystallizes monoclinic, space group C-P21/c (No. 14); a = 3.2250(6); b = 14.847(1); c = 9.1171(6) Å; β = 93.67°; Z = 4. All metal sites are octahedrally coordinated and form a two dimensional framework consisting of edge sharing octahedra ribbons. In addition one observes isolated B2O5-units and oxygen which is not coordinated to boron. The far relation to the crystal structure of the mineral Warwickite is illustrated. 相似文献
995.
Bredikhina Z. A. Pashagin A. V. Savel"ev D. V. Bredikhin A. A. 《Russian Chemical Bulletin》2001,50(3):436-439
Nonracemic -blockers, viz., (S)-propranolol and (S)-timolol, were prepared from (S)-glycidol in three steps consisting in the reaction with SOCl2 followed by the reaction of the resulting (4S)-4-chloromethyl-2-oxo-1,3,2-dioxathiolanes with the corresponding phenol and the final cleavage of (4R)-aryloxymethyl sulfites under the action of amines in DMF. 相似文献
996.
997.
Enthalpies of dissolution of benzo-15-crown-5 ether (B15C5) in mixtures of acetonitrile with water and in solutions of NaI and NaBPh4 (I=0.05 mol dm–3) in these mixtures were measured at 298.15 K. From the obtained results and appropriate literature data, the thermodynamic functions of B15C5/Na+ complex formation in acetonitrile-water mixtures were determined. The enthalpies of transfer of the complex B15C5/Na+ from pure acetonitrile to the examined mixtures were calculated and are discussed. 相似文献
998.
Designing peptide inhibitors of the p53-MDM2 interaction against cancer is of wide interest. Computational modeling and virtual screening are a well established step in the rational design of small molecules. But they face challenges for binding flexible peptide molecules that fold upon binding. We look at the ability of five different peptides, three of which are intrinsically disordered, to bind to MDM2 with a new Bayesian inference approach (MELD × MD). The method is able to capture the folding upon binding mechanism and differentiate binding preferences between the five peptides. Processing the ensembles with statistical mechanics tools depicts the most likely bound conformations and hints at differences in the binding mechanism. Finally, the study shows the importance of capturing two driving forces to binding in this system: the ability of peptides to adopt bound conformations () and the interaction between interface residues (). 相似文献
999.
高效液相色谱-串联质谱法同时测定表层水体中5类40种抗生素 总被引:1,自引:0,他引:1
建立了固相萃取-高效液相色谱-串联质谱(SPE-HPLC-MS/MS)同时检测表层水中5类40种抗生素的分析方法。水样经过滤、固相萃取柱富集净化后,以乙腈-0.2%(v/v)甲酸水溶液为流动相进行梯度洗脱,采用电喷雾电离源,在多反应监测、正离子模式进行定性定量分析。结果显示,40种抗生素在1~200 μg/L水平下线性关系良好,平均加标回收率为41.3%~112.6%。采用该方法对长江南京段表层水体进行检测,共检出13种抗生素,含量为13.4~780.5 ng/L,其中喹诺酮类抗生素恩诺沙星检出率达100%,大环内酯类抗生素克林霉素最高检出水平达739.4 ng/L。该法高效、灵敏、可靠,可用于实际水样中多种抗生素的分析。 相似文献
1000.