Investigation of the Thermal Degradation of Polyurea: The Effect of Ammonium Polyphosphate and Expandable Graphite

Polyurea was compounded with ammonium polyphosphate and expandable graphite and the morphology was studied by atomic force microscopy. The thermal degradation of polyurea and polyurea compounded with the additives has been investigated using thermogravimetry coupled with Fourier Transform infrared spectroscopy and mass spectrometry. The study of the thermal degradation and the parameters affecting the thermal stability of PU is essential in order to effectively design flame retarded polyurea. In general, thermal decomposition of polyurea occurs in two steps assigned to the degradation of the hard segment and soft segment, respectively. Adding these additives accelerates the decomposition reaction of polyurea. However, it is clear that more char is formed. This char is thermally more stable than the carbonaceous structure obtained from neat PU. The intumescent shield traps the polymer fragments and limits the evolution of small flammable molecules that are able to feed the flame

On the chemistry of hydrides of N atoms and O+^+ ions

Previous work by various authors has suggested that the detection by Herschel/HIFI of nitrogen hydrides along the low density lines of sight towards G10.6-0.4 (W31C) cannot be accounted for by gas-phase chemical models. In this paper we investigate the role of surface reactions on dust grains in diffuse regions, and we find that formation of the hydrides by surface reactions on dust grains with efficiency comparable to that for H$_2$ formation reconciles models with observations of nitrogen hydrides. However, similar surface reactions do not contribute significantly to the hydrides of O$^+$ ions detected by Herschel/HIFI present along many sight lines in the Galaxy. The O$^+$ hydrides can be accounted for by conventional gas-phase chemistry either in diffuse clouds of very low density with normal cosmic ray fluxes or in somewhat denser diffuse clouds with high cosmic ray fluxes. Hydride chemistry in dense dark clouds appears to be dominated by gas-phase ion-molecule reactions.Comment: 19 pages, 4 figures, 4 tables Accepted for publication in Ap

Deleterious Non-Synonymous Single Nucleotide Polymorphisms (nsSNPs) in the Human Interleukin 12B Gene: Identification and Structural Characterization

Background: Interleukin -12B (IL12B) polymorphism has been identified as a factor in the development of various Immunological disorders and cancer. The objective of this study was to identify the non-synonymous SNPs (nsSNPs) with the strongest predicted negative impact on the function of the IL12B protein.Methods: We employed a variety of computational methods, including SIFT, PolyPhen2, PROVEAN, SNAP2 to determine the functional impact of nsSNPs. Also, In order to investigate the potential association of nsSNPs in the IL12B gene with disease, a computational analysis was conducted using PhD-SNP, SNP&GO, and Pmut. Additionally, I-mutant and MuPro were employed to predict protein stability, while ConSurf was used to identify functional domains and conserved amino acid residues within the protein. Furthermore, SOPMA was used in combination with Project Hope and MutPred2 to predict the impact of mutations on both the structure and function of proteins. Finally, we used GeneMania to analyze the gene-gene interactions of the IL12B gene with other genes.Results: Our results indicate that nine nsSNPs (G72C, G86C, C90R, C131S, Y136D, P235L, V254G, Y258H and P259S) were found to be potentially deleterious in the IL12B gene.Conclusion: Our study emphasizes the significance of identifying functional and structural polymorphisms in the IL12B gene, as they may reveal potential therapeutic targets and provide insight into the underlying mechanisms of related diseases. Further experimental investigation is necessary to fully explore the role of these nsSNPs in disease pathogenesis.Keywords: Interleukin 12B; deleterious nsSNPs; Polymorphisms.; Computational analysis