Thermo-magnetic stability of magnetic Fe3O4 nanoparticles for hyperthermia

Monodispersed Fe3O4 magnetic particles adsorbed by amylase (such as citric acid (CA), carboxymethyl chitosan (CMCH) and β-cyclodextrin (CD)) were prepared by means of co-precipitation method. The absorption character of the samples was investigated by FT-IR, TG and VSM. It was found that the carboxyl (COOH groups) of amylase reacted with the hydroxyl (OH groups) on the surface of Fe3O4 particles, resulting in the formation of iron carboxylate that was adsorbed onto Fe3O4. The induction heating properties of the magnetic Fe3O4 nanoparticles in an alternating current magnetic field were also investigated and the thermo-magnetic stability in induction heating was discussed.

When drug nanocarriers miss their target: extracellular diffusion and cell uptake are not enough to be effective

Biocompatible nanoscale iron carboxylate metal organic frameworks (nanoMOFs) already demonstrated their ability to efficiently deliver various therapeutic molecules. The versatility of the synthetic methods and functionalization strategies could further improve...

Unravelling the water adsorption in a robust iron carboxylate metal–organic framework

Scale-up of an Fe-MOF and elucidation of its water adsorption properties by PXRD, sorption measurements and molecular simulations are reported.

Biosynthesis of Coenzyme Q in the Phytopathogen Xanthomonas campestris via a Yeast-Like Pathway

Coenzyme Q (CoQ) is a lipid-soluble membrane component found in organisms ranging from bacteria to mammals. The biosynthesis of CoQ has been intensively studied in Escherichia coli, where 12 genes (ubiA, -B, -C, -D, -E, -F, -G, -H, -I, -J, -K, and -X) are involved. In this study, we first investigated the putative genes for CoQ8 biosynthesis in the phytopathogen Xanthomonas campestris pv. campestris using a combination of bioinformatic, genetic, and biochemical methods. We showed that Xc_0489 (coq7Xc) encodes a di-iron carboxylate monooxygenase filling the E. coli UbiF role for hydroxylation at C-6 of the aromatic ring. Xc_0233 (ubiJXc) encodes a novel protein with an E. coli UbiJ-like domain organization and is required for CoQ8 biosynthesis. The X. campestris pv. campestris decarboxylase gene remains unidentified. Further functional analysis showed that ubiB and ubiK homologs ubiBXc and ubiKXc are required for CoQ8 biosynthesis in X. campestris pv. campestris. Deletion of ubiJXc, ubiBXc, and ubiKXc led to the accumulation of an intermediate 3-octaprenyl-4-hydroxybenzoic acid. UbiKXc interacts with UbiJXc and UbiBXc to form a regulatory complex. Deletion analyses of these CoQ8 biosynthetic genes indicated that they are important for virulence in Chinese radish. These results suggest that the X. campestris pv. campestris CoQ8 biosynthetic reactions and regulatory mechanisms are divergent from those of E. coli. The variations provide an opportunity for the design of highly specific inhibitors for the prevention of infection by the phytopathogen X. campestris pv. campestris.

Assessment of destruction of polyethylene modified with pro-oxidants in the context of environmental safety

The paper presents the results of the evaluation of the destruction of polyethylene LDPE (hereinafter-PE), modified by prooxidants based on iron, copper and cobalt carboxylates (in the amount of 1.5 mass. % ) with accelerated thermal and ultraviolet aging for 192 hours. The assessment of degradation in the context of environmental safety included the determination of the degree of compliance of the materials with the requirements of state standard 33747-2016 "Oxo-biodegradable packaging", according to which the criterion of the efficiency of oxobiodestructionpolyolefins may be a decrease in strength and elongation at break of the sample at accelerated aging, as well as the quantitative determination of the release of formaldehyde during thermal degradation modified with prooxidants PE for comparison with the maximum permissible concentration. The rheological parameters of the materials were studied and a comparative assessment of the melt viscosity reduction and reduction with respect to elongation at break in the dynamics of accelerated thermal and UV aging of the PE modified with prooxidants in the selected time interval of 192 hours of exposure was carried out. A decrease in the relative elongation at rupture of PE containing cobalt - based prooxidant by 94% at thermal aging for 192 hours, and by 46% at ultraviolet was established. For PE modified with copper carboxylate, these values were 64 and 33 %, respectively, for PE modified with iron carboxylate – 35% and 40%, respectively. The reduction of strength by 95% of the initial value for 192 hours of temperature exposure was achieved in a sample modified with cobalt, which confirms its compliance with state standard 33747-2016. For other samples, the degree of strength reduction in the selected time interval does not allow to assess compliance with the specified standard. The release of formaldehyde during thermal aging for 192 hours per 1 g of the PE sample modified with cobalt carboxylate was 0.051 mg/m3, for PE modified with copper carboxylate – 0.032 mg/m3, for PE modified with iron carboxylate – 0.034 mg/m3. Installed excessive concentrations of formaldehyde in air hood PH with the carboxylate of cobalt 1.2 times under thermal aging 96 hours and 1.5 times the thermal ageing of a maximum of 192 hours. The reduction of the viscosity of PE containing cobalt – based prooxidant by 90% at thermal aging for 192 hours and by 10% at ultraviolet was recorded. For PE modified with copper carboxylate, these values were 9 and 2 %, respectively, for PE modified with iron carboxylate – 8 and 5%, respectively.