Light Yellowness of Down Duvet

The yellowness of new processed down duvet after exposure to light irradiation seems very mysterious,degree of its yellowness sometimes minor,other times serious,seemingly erratic.So it is very essential for down duvet manufacturers to figure out the cause of this problem.The yellowed down duvet was split into two parts firstly,one was the external fabric which treated with antidrilling finish of polyurethane(PU) in advance,the other was filled down.Results showed that yellowing of external fabric was serious while the filled down yellowness was not obvious.However,when the external fabric and the filled down from the same batch of duvet were irradiated under the same condition respectively,the result indicated both the external fabric and the filled down had not yellowed as the above duvet.Therefore,it was inferred that the external fabric's yellowing was possibly induced by one property of the filled down.Then the key performance indicators of the filled down,such as cleanliness,oxygen consumption,and microorganisms,were measured and analyzed,and the extraction liquid of the down was also analyzed by the chromogenic reaction and UV-vis spectra.Results indicated the non-decomposed hydrogen peroxide residued in the filled down which would cause a higher oxygen consumption and induce photo oxidation yellowing of the PU film on external fabric,and the degree of its yellowing increased with the concentration of residual hydrogen peroxide increasing.Hydrogen peroxide composition would speed up the photo oxidation yellowing process and decrease the IR transmittance of PU film.Meanwhile its yellowed degree aggravating.

Thionine sensitized areobic photooxidation of thiourea in acidic medium

An investigation of the thionine sensitized aerobic photooxidation of thiourea was observed spectrophotometrically at a wavelength of 598 nm.Articles reported two types of reactions which generally occur in the presence of oxygen:1)Singlet oxygen,produced by dye sensitization due to the hydrolysis that reacts with thiourea to form oxidative products like urea and other sulfur-containing fragments and 2)bleaching of dye,which leads to the reduction.The rate of reaction in all studied parameters followed first order kinetics with respect to maximum absorption of the dye in the visible band region.Reaction kinetics was significantly dependent upon the medium and the reaction accelerated more rapidly at low pH.A direct relation was exhibited between the thiourea concentration and dye sensitizer,which was not pragmatic with the concentration of dye.The reaction was effected by the temperature,and the values of energy parameters suggested that the energy of activation was low while the entropy of activation increases with the rise in temperature,which indicated a highly solvated state of intermediate complex.Lower value of ΔH* and ΔG*at elevated temperature showed that free energy is the driving force for the completion of reaction.A mechanism based on the above findings has been suggested.

The Metabolic Response of Arabidopsis Roots to Oxidative Stress is Distinct from that of Heterotrophic Cells in Culture and Highlights a Complex Relationship between the Levels of Transcripts, Metabolites, and Flux

Metabolic adjustments are a significant, but poorly understood, part of the response of plants to oxidative stress. In a previous study （Baxter et al., 2007）, the metabolic response of Arabidopsis cells in culture to induction of oxidative stress by menadione was characterized. An emergency survival strategy was uncovered in which anabolic primary metabolism was largely down-regulated in favour of catabolic and antioxidant metabolism. The response in whole plant tissues may be different and we have therefore investigated the response of Arabidopsis roots to menadione treatment, analyzing the transcriptome, metabolome and key metabolic fluxes with focus on primary as well as secondary metabolism. Using a redox-sensitive GFP, it was also shown that menadione causes redox perturbation, not just in the mitochondrion, but also in the cytosol and plastids of roots. In the first 30 min of treatment, the response was similar to the cell culture： there was a decrease in metabolites of the TCA cycle and amino acid biosynthesis and the transcriptomic response was dominated by up-regulation of DNA regulatory proteins. After 2 and 6 h of treatment, the response of the roots was different to the cell culture. Metabolite levels did not remain depressed, but instead recovered and, in the case of pyruvate, some amino acids and aliphatic glucosinolates showed a steady increase above control levels. However, no major changes in fluxes of central carbon metabolism were observed and metabolic transcripts changed largely independently of the corresponding metabolites. Together, the results suggest that root tissues can recover metabolic activity after oxidative inhibition and highlight potentially important roles for glycolysis and the oxidative pentose phosphate pathway.