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991.
992.
Paraquat-loaded alginate/chitosan nanoparticles: preparation, characterization and soil sorption studies 总被引:1,自引:0,他引:1
Silva Mdos S Cocenza DS Grillo R de Melo NF Tonello PS de Oliveira LC Cassimiro DL Rosa AH Fraceto LF 《Journal of hazardous materials》2011,190(1-3):366-374
Agrochemicals are amongst the contaminants most widely encountered in surface and subterranean hydrological systems. They comprise a variety of molecules, with properties that confer differing degrees of persistence and mobility in the environment, as well as different toxic, carcinogenic, mutagenic and teratogenic potentials, which can affect non-target organisms including man. In this work, alginate/chitosan nanoparticles were prepared as a carrier system for the herbicide paraquat. The preparation and physico-chemical characterization of the nanoparticles was followed by evaluation of zeta potential, pH, size and polydispersion. The techniques employed included transmission electron microscopy, differential scanning calorimetry and Fourier transform infrared spectroscopy. The formulation presented a size distribution of 635 ± 12 nm, polydispersion of 0.518, zeta potential of -22.8 ± 2.3 mV and association efficiency of 74.2%. There were significant differences between the release profiles of free paraquat and the herbicide associated with the alginate/chitosan nanoparticles. Tests showed that soil sorption of paraquat, either free or associated with the nanoparticles, was dependent on the quantity of organic matter present. The results presented in this work show that association of paraquat with alginate/chitosan nanoparticles alters the release profile of the herbicide, as well as its interaction with the soil, indicating that this system could be an effective means of reducing negative impacts caused by paraquat. 相似文献
993.
Nathalie Bergeon Anthony Ramirez Liang Chen Bernard Billia Jiho Gu Rohit Trivedi 《Journal of Materials Science》2011,46(19):6191-6202
994.
Zusammenfassung Frische Moosbeeren, die im Laufe der Monate November 1931–Februar 1932 untersucht wurden, zeigten durchschnittlich eine antiskorbutische Aktivität, die zwischen 100 und 200 Einheiten in 1 Liter Saft oder 80–160 Einheiten in 1 kg Produkt liegt. Es wurde kein Unterschied in der antiskorbutischen Wirkung des Saftes und der Moosbeeren—in Mengen, die dem Safte entsprechen—gefunden.bedeutet mit Abbildungen. 相似文献
995.
Inflammatory processes are involved in the etiology of diseases. We analyzed the effect of resveratrol, piceatannol, synthetic tri-acetoxystilbene (TAS), and genistein (Bonistein(TM)) on the production of inflammatory mediators including prostaglandin E2 (PGE2), tumor necrosis factor-alpha (TNF-alpha), interleukins, and chemokines, which participate in the progression of inflammation. In order to induce inflammatory responses, human peripheral blood mononuclear and/or polymorphonuclear leukocytes were stimulated with lipopolysaccharide (LPS) and interferon-gamma (IFN(gamma)) and the production of PGE2, interleukin-8 (IL-8), and TNF-alpha was determined. In response to the stimuli, genes were substantially activated within < 2 h (e. g., TNF-alpha, IL-1alpha), or at a later stage, (e. g., COX-2, IL-6, IL-8). Unlike genistein, resveratrol and related compounds dose-dependently reduced PGE2 production. Genistein, piceatannol, and TAS diminished secretion of TNF-alpha, and IL-8. TAS reduced mRNA levels of COX-2, TNF-alpha, IL-8, IL-6, and IL-1alpha, while resveratrol impaired early expression of IL-8 and TNF-alpha. Piceatannol out-performed resveratrol, yet without matching TAS. Genistein downregulated TNF-alpha and IL-8 expression. These substances altered the LPS/IFNgamma-induced gene expression in mononuclear cells rather than in polymorphonuclear leukocytes. Immunoblot analyses corroborated the distinct activity pattern of resveratrol and genistein. In conclusion, resveratrol and their derivatives attenuated the inflammatory response of PBLs at several levels, whereas genistein acts on cytokines and pro-inflammatory interleukins. 相似文献
996.
Yu Y Ding C Wang E Chen X Li X Zhao C Fan Y Wang L Beaujean N Zhou Q Jouneau A Ji W 《Reproduction (Cambridge, England)》2007,133(5):947-954
Even though it generates healthy adults, nuclear transfer in mammals remains an inefficient process. Mainly attributed to abnormal reprograming of the donor chromatin, this inefficiency may also be caused at least partly by a specific effect of the cloning technique which has not yet been well investigated. There are two main procedures for transferring nuclei into enucleated oocytes: fusion and piezoelectric microinjection, the latter being used mostly in mice. We have, therefore, decided to compare the quality and the developmental ability, both in vivo and in vitro, of embryos reconstructed with electrofusion or piezoelectric injection. In addition, the effect of piezo setups of differing electric strengths was investigated. Along with the record of the rate of development, we compared the nuclear integrity in the blastomeres during the first cleavages as well as the morphological and cellular quality of the blastocysts. Our results show that the piezo-assisted micromanipulation can induce DNA damage in the reconstructed embryos, apoptosis, and reduced cell numbers in blastocysts as well as a lower rate of development to term. Even if piezo-driven injection facilitates a faster and more efficient rate of reconstruction, it should be used with precaution and with as low parameters as possible. 相似文献
997.
Maha Mezghani-Khemakhem Dhia Bouktila Nathalie Casse Houcine Maaroufi Mohamed Makni Hanem Makni 《International journal of molecular sciences》2012,13(11):14446-14450
Using an enriched library method, seven polymorphic microsatellite loci were isolated from the barley stem gall midge, Mayetiola hordei. Polymorphism at loci was surveyed on 57 individual midges collected on barley in Tunisia. Across loci, polymorphism ranged from two to six alleles per locus. The observed heterozygosity varied between 0.070 and 0.877. Based on the number of alleles detected and the associated levels of heterozygosity, we believe that these loci will prove useful for population genetic studies on M. hordei. 相似文献
998.
Nathalie De Clercq Sabine Danthine Mai Tuyet Nguyen Veronique Gibon Koen Dewettinck 《Journal of the American Oil Chemists' Society》2012,89(2):219-229
Interesterification is an important modification technique for fats and oils resulting in the redistribution of the fatty
acids among the glycerol backbone and thus changing the physico-chemical properties of the modified fat. In this study palm
oil, palm olein and soft palm mid fraction (PMF) were subjected to both enzymatic (batchwise) and chemical interesterification.
The reaction products were characterized before, during and after interesterification by HPLC, pulsed NMR (p-NMR) and differential
scanning calorimetry (DSC). Interesterification led to more uniform triacylglycerol (TAG) compositions with smaller differences
in final physico-chemical properties between the studied substrates. The degree of interesterification was evaluated on the
basis of TAG composition and solid fat content (SFC). Significant differences between both methods were observed. The degree
of interesterification based on SFC is therefore a better tool to evaluate the rate constant of the reaction as the TAG composition
method does not take into consideration the formation of positional isomers at the end of the enzymatic process. 相似文献
999.
Electroleaching and electrodeposition of zinc in a single-cell process for the treatment of solid waste 总被引:2,自引:1,他引:1
This work deals with zinc beneficiation of industrial solid waste by an electrochemical technique combining electroleaching and electrodeposition in a single-cell process. This technique is based on leaching of the solid waste by the protons generated at the anode and migration of the resulting ions toward the cathode where deposition takes place. A laboratory cell was built for testing the method. It consisted of three compartments, two electrode compartments and a solid waste chamber placed between these. Catholyte and anolyte were sulphuric/sulphate solutions at optimised concentrations. Experiments were first carried out using a zinc solution and an inert matrix in the central compartment, then using a synthetic waste prepared by dispersing zinc oxide in silicon dioxide. Best performance was obtained with treatment duration of 6h, at 4.5Adm(-2) and with catholyte circulation. In this case, a 97% of zinc oxide lixiviation and 75% of zinc-plated were achieved. 相似文献
1000.