Recently, chitosan (CS) was given much attention as a functional biopolymer for designing various hydrogels for industrial, environmental and biomedical applications, but their biomedical use is limited due to the toxicity of the crosslinker agents. To overcome this inconvenience, we developed an auto cross-linked material based on a chitosan backbone that carries an amino and aldehyde moieties. This new drug delivery system (DDS) was designed by using oxidized chitosan (OCS) that crosslinks chitosan (CS). In the first part, a simple, rapid, low-cost and eco-friendly green method was introduced to synthesize magnetite nanoparticles (Fe3O4-NPs) successfully. These nanoparticles Fe3O4 have received a great deal of attention in the biomedical field. Especially in a targeted drug delivery system, drug-loaded Fe3O4-NPs can accumulate at the tumor site by the aid of an external magnetic field and increase the effectiveness of drug release to the tumor site. In the second part, we have incorporated the Fe3O4-NPs into chitosan/oxidized chitosan solution because of their unique magnetic properties, outstanding magnetism, biocompatibility, lower toxicity, biodegradability, and other features. Three drugs (5-Fluorouracil (5-FU), Caffeine and Ascorbic acid)) were embedded into the magnetite solution that became quickly a hydrogel. The successful fabrication of the hydrogels and ferrogels was confirmed by (FT-IR), (TGA), (SEM), (VSM) analysis at room temperature. Finally, results showed that our hydrogels and ferrogels may be technologically used as devices for drug delivery in a controllable manner.
As part of our research on substituted benzimidazoles, we are interested in the synthesis of new heterocyclic molecules. This new organic molecule is a subclass of quinolines with a wide variety of biological properties. In order to affect the binding of quinoline to our bis-benzimidazole derivatives, we have chosen the "azo" bond as a means of attachment. To achieve our goal, we investigated different parameters for the reactions to determine the conditions to obtain the best results. This article discusses the antioxidant activity of our molecules using the DPPH method.
<p>Chemical activation was used to prepare a low-cost activated carbon (AC) from an agricultural waste material: sugarcane bagasse. It was used as a green biosorbent for the removal of two cationic dyes from aqueous solutions (Methylene blue (MB) and Malachite Green (MG)). Central composite design (CCD) using response surface methodology (RSM) was applied in this work in order to run a limited number of experiments. The possibility of revealing the interaction of three selected factors: activation temperature, activation time, and chemical impregnation ratios at different levels for the process of preparing the AC were studied. Two-second order quadratic regression models for a yield of AC and capacity of adsorption were developed using JMP Software.</p><p>The results of the process of optimization were carried out; it showed a good agreement between the predictive response of RSM model and the obtained experimental values with high correlation coefficients (R<sup>2</sup>) which indicates the efficacy of the model. The optimal activated carbon was obtained using 400°C activation temperature, 36 min activation time, and 2 impregnation ratio, resulting in 63.12 % of AC yield and 99.86 % for MB removal and 400°C activation temperature, 90 min activation time and 2 impregnation ratio, resulting in 45.69 % of AC yield and 99.75 % for MG removal. Moreover, the comparison between the experimental and the predicted values at optimum conditions was in good agreement with relatively small errors.</p><p>This work showed the effectiveness and the performance of preparing activated carbon from sugarcane bagasse, and it recommended as an effective and green biosorbent for the removal of cationic dyes from aqueous solutions.</p>
Proton NMR is a method of molecular investigation that has its limitations when applied to complex molecules or molecules with many nearly equivalent sites. Previous studies have resorted to the use of paramagnetic chemical shift reagents, having as formula tris (tetraphenylimidodiphosphinate) of lanthanides ln((tpip.)3. The use of reagent Pr(tpip)3 in proton RMN has allowed us to evaluate the autoxidation of fatty acids mixture (stored 6 and 12 months after oil extraction) by the dosage of saturated and unsaturated acids on the one hand, and that of oleic and linoleic acids on the other. We note between 6 and 12 months of storage at 4°C a decrease in the percentage of unsaturated acids (76% to 63%) and an increase in the percentage of saturated acids (24% to 36%). The results show that the oleic acid maintained the same percentage (35%) as it is not easily oxidized whereas, for the linoleic acid, we observe a decrease in percentage from 22.5% to 18.5% (slow autoxidation at 4°C). We also used this NMR method for the analysis of the argan pulp fatty part. The GC analysis shows that it contains very few unsaturated fatty acids and that the main fatty acids are myristic (C14:0) and palmitic (C16:0) acids. The proton NMR with Pr(tpip)3 allowed us to confirm these results. This method that does not require derivation has proven to be interesting, simple and efficient.
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