1-Hexene Ozonolysis across Atmospheric and Combustion Temperatures via Synchrotron-Based Photoelectron Spectroscopy and Chemical Ionization Mass Spectrometry.

This study investigates the complex interaction between ozone and the autoxidation of 1-hexene over a wide temperature range (300-800 K), overlapping atmospheric and combustion regimes. It is found that atmospheric molecular mechanisms initiate the oxidation of 1-hexene from room temperature up to combustion temperatures, leading to the formation of highly oxygenated organic molecules. As temperature rises, the highly oxygenated organic molecules contribute to radical-branching decomposition pathways inducing a high reactivity in the low-temperature combustion region, i.e., from 550 K. Above 650 K, the thermal decomposition of ozone into oxygen atoms becomes the dominant process, and a remarkable enhancement of the conversion is observed due to their diradical nature, counteracting the significant negative temperature coefficient behavior usually observed for 1-hexene. In order to better characterize the formation of heavy oxygenated organic molecules at the lowest temperatures, two analytical performance methods have been combined for the first time: synchrotron-based mass-selected photoelectron spectroscopy and orbitrap chemical ionization mass spectrometry. At the lowest studied temperatures (below 400 K), this analytical work has demonstrated the formation of the ketohydroperoxides usually found during the LTC oxidation of 1-hexene, as well as of molecules containing up to nine O atoms.

Facile synthesis of chitosan/ZnO bio-nanocomposite hydrogel beads as drug delivery systems.

ZnO nanoparticles were synthesized in situ during the formation of physically cross-linked chitosan hydrogel beads using sodium tripolyphosphate as the cross-linker. The aim of the study was to investigate whether these nanocomposite beads have the potential to be used in drug delivery applications. The formation of ZnO nanoparticles (ZnONPs) in the hydrogels was confirmed by X-ray diffraction and scanning electron microscopy studies. SEM micrographs revealed the formation of ZnONPs with size range of 10-25 nm within the hydrogel matrix. Furthermore, the swelling and drug release properties of the beads were studied. The prepared nanocomposite hydrogels showed a pH sensitive swelling behavior. The ZnO nanocomposite hydrogels have rather higher swelling ratio in different aqueous solutions in comparison with neat hydrogel. In vitro drug release test was carried out to prove the effectiveness of this novel type of nanocomposite beads as a controlled drug delivery system. A prolonged and more controlled drug releases were observed for ZnONPs containing chitosan beads, which increased by the increase in ZnONPs content.

Facile synthesis of antibacterial chitosan/CuO bio-nanocomposite hydrogel beads.

CuO nanoparticles were synthesized in situ during the formation of physically cross-linked chitosan hydrogel beads using sodium tripolyphosphate as the cross-linker. The aim of the study was to investigate whether these nanocomposite beads have the potential to be used in drug delivery applications. The formation of CuO nanoparticles (CuONPs) in the hydrogels was confirmed by X-ray diffraction and scanning electron microscopy studies. SEM micrographs revealed the formation of CuONPs with size range of 10-25 nm within the hydrogel matrix. Furthermore, the antibacterial and swelling properties of the beads were studied. The prepared nanocomposite hydrogels showed a pH sensitive swelling behavior. The CuO nanocomposite hydrogels have rather higher swelling in different aqueous solutions in comparison with neat hydrogel. The nanocomposite hydrogels demonstrated good antibacterial effects against Escherichia coli and Staphylococcus aureus bacteria.

One-pot synthesis of antibacterial chitosan/silver bio-nanocomposite hydrogel beads as drug delivery systems.

Silver nanoparticles were synthesized in situ during the formation of physically crosslinked chitosan hydrogel beads using sodium tripolyphosphate as the crosslinker. The aim of the study was to investigate whether these nanocomposite beads have the potential to be used in drug delivery applications. The formation of silver nanoparticles (AgNPs) in the hydrogels was confirmed by X-ray diffraction and scanning electron microscopy studies. Furthermore, the antibacterial and swelling properties of the beads were studied. The nanocomposite hydrogels demonstrated good antibacterial effects against Escherichia coli and Staphylococcus aureus bacteria. AgNPs caused an increase in the swelling capacity of the beads. In vitro drug release test was carried out to prove the effectiveness of this novel type of nanocomposite beads as a controlled drug delivery system. Prolonged and more controlled drug releases were observed for AgNPs containing chitosan beads, which increased by the increase in AgNPs content.