RESUMEN
Millions of tons of feather are produced worldwide each year and considered as a solid waste owing to technical or cost constraints to provide valuable functional characteristics. In this study, a novel and ecofriendly method to recycle waste feather and obtain a type of explosion down via flash explosion with a supercritical fluid of carbon dioxide (SCF-CO2) was developed for the first time. The effects of flash explosion parameters on the structures and properties of feather were explored by orthogonal experiments. A mechanism involving two-step procedures for the developed SCF-CO2 flash explosion is proposed. The obtained results indicate that reinforcements of flash explosion conditions, particularly the system pressure, were readily conducive to transfer the original feather to a soft down with an improved separation ratio, as well as easily weaken or break hydrogen and disulfide bonds associated in feather macromolecules. Moreover, efficient modifications of the physical characteristics, structures and surface morphologies of the waste feather were obtained by the SCF flash explosion to produce a uniform, slender and fibrous explosion down, as demonstrated by scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction analysis. Further tests on the SCF explosion down treated at 70.0 °C at 15.0 MPa for 30.0 min and at 90.0 °C at 20.0 MPa for 20.0 min showed remarkable enhancements in warmth retention along with comparable thermal degradation nature, as well as enhanced softness, down-proof, and other service properties in comparison to the original feather. The SCF-CO2 flash explosion is a promising approach with environment-friendly characteristics to obtain high efficiency and quality of the explosion down by recycling of waste feather.
RESUMEN
Disperse reactive dyes with appropriate chemical structure are key for the coloration of natural fibers in the water-free environmentally friendly medium of supercritical carbon dioxide with various advantages. The objective of this work is to design and synthesize a novel anthraquinonoid disperse reactive dye involving a versatile bridge group to improve the coloration properties of the dye in supercritical carbon dioxide. Cross-coupling condensation based on an Ullmann reaction between N-phenylethylenediamine and 1-chloroanthraquinone in a ligand-free system is investigated by optimizing the synthesis parameters. Notable influences are observed from the dosages of N,N-dimethyl formamide and potassium hydroxide, as well as the system temperature and reaction duration, on the isolated yield of the dye precursor. An optimized process is also recommended for synthesizing the designed novel dye. Then, the chemical structure, color characteristics, and coloration properties of the obtained dye are further investigated and successfully characterized by utilizing Fourier-transform infrared analysis, 1H and 13C nuclear magnetic resonance spectroscopy, UV-vis absorption spectroscopy, elemental analysis, and liquid chromatography-mass spectrometry. Additionally, practical coloration experiments are performed with cotton, silk, and wool in a supercritical carbon dioxide medium.
RESUMEN
The results of previous studies evaluated the accuracy of serum, and urinary measurements of cytokeratin-19 fragment (CYFRA 21-1) for the diagnosis of bladder cancer were inconsistent. We read with great interest the recent systematic review of diagnostic accuracy of CYFRA 21-1 for bladder cancer by Huang et al. The systematic analysis demonstrated that the pooled sensitivities and specificities for serum and urine CYFRA 21-1 were 0.42 (95 % confidence interval (CI), 0.33-0.51), 0.82 (95 % CI, 0.70-0.90), 0.94 (95 % CI, 0.90-0.96), and 0.80 (95 % CI, 0.73-0.86), respectively. Areas under the summary receiver-operating-characteristic curves for serum and urine CYFRA 21-1 were 0.88 (95 % CI, 0.85-0.91) and 0.87 (95%CI, 0.84-0.90), respectively. The authors considered that both serum and urine CYFRA 21-1 served as efficient indexes for bladder-cancer diagnosis. We congratulate and applaud their important work, but several important issues should be noted.
