Carbamoyl fluorides are formed in reactions of hydroxylamines with difluorocarbene generated from sodium bromodifluoroacetate as readily available and non‐toxic carbene precursor. The process shows a high functional group tolerance, and the reaction path has been rationalized by computational calculations.
With the increasing interest in biopolymer nanofibers for diverse applications, the characterization of these materials in the physiological environment has become of equal interest and importance. This study performs first-time simulated body fluid (SBF) degradation and tensile mechanical analyses of blended fish gelatin (FGEL) and polycaprolactone (PCL) nanofibrous meshes prepared by a high-throughput free-surface alternating field electrospinning. The thermally crosslinked FGEL/PCL nanofibrous materials with 84–96% porosity and up to 60 wt% PCL fraction demonstrate mass retention up to 88.4% after 14 days in SBF. The trends in the PCL crystallinity and FGEL secondary structure modification during the SBF degradation are analyzed by Fourier transform infrared spectroscopy. Tensile tests of such porous, 0.1–2.2 mm thick FGEL/PCL nanofibrous meshes in SBF reveal the ultimate tensile strength, Young's modulus, and elongation at break within the ranges of 60–105 kPa, 0.3–1.6 MPa, and 20–70%, respectively, depending on the FGEL/PCL mass ratio. The results demonstrate that FGEL/PCL nanofibrous materials prepared from poorly miscible FGEL and PCL can be suitable for selected biomedical applications such as scaffolds for skin, cranial cruciate ligament, articular cartilage, or vascular tissue repair. 相似文献
The objective of this study was to evaluate the functional properties of lactic acid bacteria (LAB) from kimchi, a traditional Korean fermented vegetable product generally consumed raw as a side-dish with practically every meal.Twelve mild acid producing facultatively heterofermentative Lactobacillus strains were selected for their potential as starter cultures for fermentation of kimchi, and evaluated for their functional properties. Eleven strains were identified as Lactobacillus sakei and one as Lactobacillus plantarum. The strains identified as L. sakei differed in some physiological features; of particular interest was the fact that 9 of these strains produced L(+) lactic acid from glucose in presence of acetate.All strains were able to survive gastrointestinal conditions simulating stomach and duodenum passage. In addition, they showed higher adherence to HT-29 cells than Lactobacillus rhamnosus GG, a commercial probiotic strain used worldwide. These strains also showed antimicrobial activity against a number of food-borne pathogens. Their ability to lower cholesterol was demonstrated by BSH (bile salt hydrolytic) activity, and cholesterol assimilation tests in vitro. The results suggest the probiotic potential of these strains for use in kimchi fermentation. 相似文献
The cover image, by Hannah C Wells et al., is based on the Research Article Deer leather: analysis of the microstructure affecting pebble, DOI: 10.1002/jsfa.8199 .
Mechanochemical activation of solids can lead to a strong increase in their activity as catalysts in heterogeneously catalyzed reactions. In the following, we report on the effects of solid catalyst activation during ball milling that lead to oscillatory behavior in CO and CO2 formation during propene oxidation. The oscillations arise under in situ ball milling conditions over chromium(III) oxide (Cr2O3) and cerium(IV) oxide (CeO2), respectively. The experiments were conducted under continuous gas flow at ambient pressure and temperature, using both a modified steel and a tungsten carbide milling vessel. Abrasion of particles from the steel milling vessel could be eliminated as the sole cause for the oscillations through substitution by a tungsten carbide milling vessel. The intensity and frequency of oscillations are shown to be dependent on the propene-to-oxygen ratio, the milling frequency, milling ball size and metal oxide used. Overall, Cr2O3 shows higher activity for oscillatory propene combustion under in situ mechanical activation than CeO2. 相似文献