Chiral plasmonic nanocrystals are promising materials for applications in enantioselective catalysis, DNA detection, and medical diagnosis. Herein, we demonstrate a simple and versatile strategy that produces plasmonic nanostructures with strong chiroptical responses by a chiral ligand mediated seeded growth approach. By modulation of the surface coverage of chiral ligands on Au nanotriangles, propeller-like structures with the growth of three arms on the tips of the triangles are produced with a high anisotropy factor. Finally, these Au chiral propellers can be used as substrates for the surface-enhanced Raman scattering (SERS) detection of chiral biomolecules, achieving chiral differentiation for enantiomers of biomolecules.

No abstract

The objective of this paper was to develop a nonlinear chemical fingerprint technique for identifying and detecting adulteration of goat milk with cow milk. In this study, by taking the Belousov-Zhabotinsky oscillatory chemical reaction using acetone and substrates in goat milk or cow milk as main dissipative substances, when the same dosage of goat milk and cow milk was introduced to the "H + Mn + BrO + acetone" oscillating system respectively, nonlinear chemical fingerprints were obtained for goat milk and cow milk from the same origin. The results showed that inductive time value and the content of cow milk in goat milk had a linear relationship in the range of 0-100% and the corresponding regression coefficient was 0.9991. A detection limit of 0.0107 g/g was obtained, and the content of cow milk in mixed milk was calculated. The proposed method in this study was simple, economical and effective. In addition, the method did not need the pretreatment and separation of samples for identifying and evaluating cow milk adulteration in goat milk.

The development of novel solid-state fluorescence switches, particularly triggered by visible light, is of increasing interest for the potential application in optical data storage and super-resolution fluorescence microscopies. In this study, two carbazole–dithienylethene–BF2bdk triads CDB1 and CDB2, suspending carbazole and BF2bdk moieties on both sides of dithienylethene unit, have been developed. They exhibit blue-/NIR light-controlled photochromism with solvent-dependent characteristics. Moreover, CDB1 (o) reveals blue-/NIR light-induced reversible fluorescent switching behaviors in toluene, chloroform, poly­(methyl methacrylate) (PMMA) film, and powder state, while its analogue CDB2 (o) in the powder state exhibits no fluorescence due to a strong intermolecular π–π stacking interaction, and the fluorescent switching performance is observed only in toluene and PMMA film. The density functional theory calculations further validate the differences in their optical properties in the solution and powder states.

No abstract

No abstract

Background Semen cryopreservation has become an essential tool for conservation efforts of the giant panda (Ailuropoda melanoleuca); however, it is severely detrimental to sperm quality. Evidence has shown that antioxidants have the potential to reverse cryopreservation-induced damage in sperm. The purpose of this study was to screen effective antioxidants that could retain sperm quality during cryopreservation and to determine the optimal dose. Seven antioxidant groups, including resveratrol (RSV = 50 μM, RSV = 100 μM, RSV = 150 μM), lycium barbarum polysaccharide (LBP = 2 mg/mL, LBP = 4 mg/mL), laminaria japonica polysaccharides (LJP = 1 mg/mL) or combination (LBP = 2 mg/mL, LJP = 1 mg/mL and RSV = 100 μM) were assessed. Results RSV, LBP, LJP, or a combination of RSV, LBP, and LJP added to the freezing medium significantly improved sperm progressive motility, plasma membrane integrity, acrosome integrity, and mitochondrial activity during the cryopreservation process. Furthermore, the activities of glutathione peroxidase and superoxide dismutase were also improved. The levels of reactive oxygen species and malondialdehyde in semen were notably reduced. Hyaluronidase activity and acrosin activity were significantly increased in LBP-treated sperm. However, sperm total motility and DNA integrity were not significantly different between the groups. Conclusions RSV (50 μM) or LBP (2 mg/mL) are the best candidate antioxidants for inclusion in the freezing medium to improve the quality of giant panda spermatozoa during semen cryopreservation.

Electromagnetic interference (EMI) shielding rubber nanocomposites were fabricated via a simple rubber roll milling technique based on the filler distribution behavior in the immiscible natural rubber (NR) and acrylonitrile-butadiene (NBR) (50/50) blends with varying amounts of multiwall carbon nanotubes and Fe 3 O 4 nanoparticles. All nanocomposites showed a co-continuous phase structure, while the distribution behavior of filler was diverse correlated with the filler content and type. The mechanical properties, electrical conductivity, and EMI shielding effectiveness (SE) of rubber composites were characterized. The maximum EMI SE of 29.4 dB at 12.4 GHz was achieved in the rubber composites loaded with 15 phr MWCNTs and 15 phr Fe 3 O 4 nanoparticles. The EMI shielding mechanisms of such materials were also discussed. The observation in this work provided a possible idea to the industrial manufacture electromagnetic interference shielding rubber nanocomposites, and contributed to expanding its application fields with higher mechanical property requirements and flexibility.