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31.
Synthesis of Spirocyclic and Tricyclic Isoxazoline via 1,3‐Dipolar Cycloaddition Reactions 下载免费PDF全文
1,3‐Dipolar cycloadditions of the bicyclic monoterpenes (S)‐(?)‐camphene ( 1 ), (R)‐(+)‐a‐pinene ( 2 ), and (S)‐(?)‐b‐pinene ( 3 ) with aryl and heteroaryl nitrile oxides afforded new spirocyclic and tricyclic isoxazoline derivatives 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 whose biological activities were evaluated in bioassay studies. 相似文献
32.
A method combining immunomagnetic separation (IMS) and surface-enhanced Raman scattering (SERS) was developed to enumerate Escherichia coli (E. coli). Gold-coated magnetic spherical nanoparticles were prepared by immobilizing biotin-labeled anti-E. coli antibodies onto avidin-coated magnetic nanoparticles and used in the separation and concentration of the E. coli cells. Raman labels have been constructed using rod shaped gold nanoparticles coated with 5,5-dithiobis-(2-nitrobenzoic acid) (DTNB) and subsequently with a molecular recognizer. Then DTNB-labeled gold nanorods were interacted with gold-coated magnetic spherical nanoparticle-antibody-E. coli complex. The capture efficiency and calibration graphs were obtained and examined in different E. coli concentrations (10(1)-10(7) cfu mL(-1)). The correlation between the concentration of bacteria and SERS signal was found to be linear within the range of 10(1)-10(4) cfu mL(-1) (R(2) = 0.992). The limit of detection (LOD) and limit of quantification (LOQ) values of the developed method were found to be 8 and 24 cfu mL(-1), respectively. The selectivity of the developed immunoassay was examined with Enterobacter aerogenes, Enterobacter dissolvens, and Salmonella enteriditis which did not produce any significant response. The ability of the immunoassay to detect E. coli in real water samples was also investigated and the results were compared with the experimental results from plate-counting methods. There was no significant difference between the methods that were compared (p > 0.05). This method is rapid and sensitive to target organisms with a total analysis time of less than 70 min. 相似文献
33.
Synthesis and characterization of nanomagnetite particles and their polymer coated forms 总被引:1,自引:0,他引:1
Utkan GG Sayar F Batat P Ide S Kriechbaum M Pişkin E 《Journal of colloid and interface science》2011,353(2):372-379
Superparamagnetic nanoparticles were prepared by coprecipitation of ferrous (Fe(2+)) and ferric (Fe(3+)) aqueous solution by a base. Nanomagnetite particles were coated with poly(St/PEG-EEM/DMAPM) and poly(St/PEG-MA/DMAPM) layer by emulsifier-free emulsion polymerization. Chemical structure of nanoparticles was characterized by both FTIR and (1)H NMR. Particle morphologies were determined by Zeta Sizer, DLS, XRD and SAXS. Structural analysis showed that after polymer coating nanomagnetite particles kept their superparamagnetic property. Besides the synthesized magnetites, polymer coated forms of these particles are more biocompatible, well dispersable and uniform. These properties make them a very strong candidate for bioengineering applications, such as bioseparation, gene transfer. 相似文献
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The authors have investigated the effect of the degree of extension on the strength and shrinkage of polyisoprene chloride rubber film. It is shown that the breaking strength and shrinkage at elevated temperatures are determined only by the degree of extension in the corresponding direction and are almost independent of the extension in the other direction.Mekhanika Polimerov, Vol. 2, No. 3, pp. 350–354, 1966 相似文献
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During processing of polypropylene and alkali sulfate lignin at a temperature of 180° C, a reaction occurs resulting in the formation of a polymer which appears to have a three-dimensional structure. The observed cross-linking is accompanied by an increase in reversible deformation, a decrease in irreversible deformation, a transition from solubility to limited swelling in solvents, an increase in tensile strength, and an increase in freeze resistance. This is achieved by also adding a plasticizer to the polymer.Mekhanika Polimerov, Vol. 1, No. 6, pp. 3–9, 1965 相似文献
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The dynamic fatigue of composite film materials has been studied as a function of the frequency and amplitude of deformation. The tests were carried out on a vibration apparatus with a frequency range from 10 to 600 cps. The test objects consisted of foil packaging with a polyethylene backing (foil-film).The dependence of the dynamic fatigue of foil-film on amplitude, frequency, and acceleration was studied. It has been shown that in all cases failure of the material is preceded by cracking of the foil and peeling of the foil from the polyethylene backing at the site of the cracks. The material fails as a result of puncture of the polyethylene backing by the broken edge of the cracked foil.Mekhanika Polimerov, Vol. 1, No. 5, pp. 90–94, 1965 相似文献
40.
Yeon Hee Cho Seung Gul Rha Suk-Kyu Chang Taek Dong Chung Keunchang Cho Hasuck Kim 《Journal of inclusion phenomena and macrocyclic chemistry》1998,31(2):119-129
A series of bis(crown ether)sbased-upon a xanthene-4,5-dicarboxylic acid skeletonwas prepared and their ionophoric properties towardalkali metal cations were investigated. Bis(crownether)s bearing 15-crown-5 and 18-crown-6 moietiesexhibited pronounced extraction efficiencies towardK+ and Cs+ ions, respectively, and theextraction constant estimated by solvent extractionstudies was as high as 109 for the 2-K+ and 3-Cs+ systems. Using UVtitration of potassium picrate with 2 in THF, thecomplex was found to have a structure of a completelyencapsulated guest in the host. In transportexperiments, the bis(crown ether)s showed nosignificant selectivity pattern compared withextraction results, again implying the strongcomplexation of bis(crown ether)s. Ion-selectiveelectrode studies also demonstrated that the selectiveionophoric properties of 2 toward K+ werereminiscent of the natural antibiotic valinomycinexcept for a somewhat slow response. 相似文献