Synthesis and characterization of cellulose acetate from cellophane industry residues. Application as acetaminophen controlled-release membranes

Journal of Thermal Analysis and Calorimetry - Cellophane film production generates cellulosic residues from scraps, edges, and low-quality films. In this work, cellophane was used as a raw material...     

A Galactomannan-Driven Enhancement of the In Vitro Multiplication Rate for the Marubakaido Apple Rootstock (<Emphasis Type="Italic">Malus prunifolia</Emphasis> (Willd.) Borkh) is Not Related to the Degradation of the Exogenous Galactomannan

Agar is a complex mixture of gel-forming polysaccharides. Gelling agents are very often used to provide proper support for plants grown in semisolid culture media. And agar is the most frequently used gelling agent in plant tissue culture media. Galactomannans, another group of gel-forming polysaccharides, consists of a (1 → 4)-linked β-d-mannopyranosyl backbone partially substituted at O-6 with d-galactopyranosyl side groups. In this work, we demonstrate that a statistically significant 2.7-fold increase on the multiplication rate (MR) for in vitro-grown Marubakaido (Malus prunifolia) shoots was associated with a 12.5% replacement of agar in the semi-solid culture media for a galactomannan obtained from seeds of Schizolobium paraybae. This increase on MR was due mainly to a 1.9-fold increase in the number of main branches and an 8.6-fold increase in the number of primary lateral branches. Gas liquid chromatography and thin layer chromatography analyzes demonstrated that the galactomannan-driven enhancement of the in vitro multiplication rate of the Marubakaido apple rootstock was not related to the galactomannan degradation. To the best of our knowledge, this is the first report on the successful use of partial replacement of high quality agar by a galactomannan from S. paraybae in a micropropagation system for a tree species.     

Bacterial nanocellulose containing diethylditiocarbamate bio-curatives: physicochemical characterization and drug delivery evaluation

Bacterial nanocellulose (BNC) is a natural biopolymer produced by different strains of acetic acid bacteria. Biocompatibility, lack of immunogenicity, mechanical strength and crystallinity make BNC a highly applicable product for drug delivery and wound dressing. Previously, we demonstrated that diethylditiocarbamate (DETC), a Superoxide Dismutase 1 inhibitor, incorporated into BNC bio-curatives was effective for treating Cutaneous leishmaniasis (CL) lesions, a parasitic disease caused by Leishmania. We herein investigated the interactions between DETC and BNC. For this purpose, DETC was incorporated into BNC and thermal analysis, x-ray diffraction and Scanning electron microscopy were performed. Furthermore, in vitro DETC release and stability tests as well as degradation studies were also performed. Our results show that DETC is well incorporated into BNC, however it is short lived as suggested by degradation experiments. Future use of BNC DETC-based bio-curatives for the treatment of CL shall require further development in order to increase stability of DETC in the bio-curative.

     

Evaluation of physico-chemical properties and antimicrobial synergic effect of ceftazidime-modified chitosan

The aim of this work was to study the effect of tris(3-nitrophenyl) phosphine (NPPh3), which showed a good thermal stability and carbon-forming ability, on the flame retardancy and thermal degradation mechanism of epoxy resins. A series of diglycidyl ether of bisphenol A (DGEBA) loaded with tris(3-nitrophenyl) phosphine (NPPh3) were prepared. It was found that NPPh3 can effectively improve the flame retardancy and thermal stability of the composites. When the loading amount of NPPh3 was 14%, the LOI value of the DGEBA composites was 29.2% (about 1.53 times the corresponding value of the original DGEBA resin). Thermal stability was studied by thermogravimetric analysis, and the results showed that the addition of NPPh3 can improve char formation of this system both in nitrogen and in air atmosphere. Specifically, its combustion residue at 800 °C in nitrogen atmosphere was about 4.26 times of the original resin. Differential scanning calorimetry indicated that NPPh3 slightly decreased the glass transition temperature of epoxy resins. Additionally, the gaseous degradation products were analyzed by thermogravimetric analysis/infrared spectrometry, providing insight into the thermal degradation mechanism. Scanning electron microscopy and Fourier transform infrared were brought together to evaluate the morphology and structure of the residual char obtained after combustion.