Calix[4]arene-based Supramolecular Gels for Mercury Ion Removal in Water.

A calix[4]arene-based gelator 1, with lower-rim mono triazolylpyridine group, capable of spontaneous self-assembly into microspheres in different ethanol/H2 O mixtures, is synthesized. The concentration-dependent 1 H NMR spectra and X-ray single-crystal structure of 1 provided evidence for self-assembly of gelator 1 via cooperative interactions of intermolecular noncovalent forces. Furthermore, metallogels by self-assembly of 1 was found to exhibit remarkable selectivity toward Hg2+ ions. 1 H NMR spectra support that Hg2+ ion was bound to the nitrogen atoms of two coordination sites of 1, which composed of triazole and pyridine. Moreover, the results of field emission scanning electron microscopy and rheology experiments indicated that Hg2+ ions not only enhanced the gelling ability of gelator 1 in ethanol but also led to morphological change of its self-assembly through metal-ligand interactions. Finally, the in situ gelation, triggered by mixing a gelator solution of 1 in ethanol with water samples such as deionized (DI), tap, and lake water, leads to the effective removal of Hg(II) from a water sample which reduced from 400 to 1.6 ppm.

Effects of different cryoprotectants and freezing methods on post-thaw boar semen quality.

The current study aimed to investigate the effects of different concentrations of glycerol (0%, 1%, 2%, 3%, and 5%) and dimethylacetamide (DMA: 0%, 1%, 3%, and 5%) on post-sperm quality characteristics following semen freezing in dry ice (D) or liquid nitrogen (N). Semen was collected from Duroc boars and was allocated to 32 treatment groups for cryopreservation. Analysis of post-thaw semen quality and fertility after artificial insemination (AI) was used to examine the combinatorial effects of different treatments. The best scores for post-thaw sperm motility, sperm viability, and sperm acrosomal integrity were observed in semen frozen in: (a) dry ice in the presence of 5% glycerol and no DMA (16D-treatment); (b) dry ice in the presence of 3% glycerol and no DMA (9D-treatment); and (c) liquid nitrogen in the presence of 3% glycerol and 1% DMA (10N-treatment), with no significant difference observed among these three treatments. The farrowing rates after AI with post-thawed semen after 9D- and 10N-treatments were 33% and 50%, respectively. To summarize, the results of the present study indicated that the freezing extender containing 3% glycerol in combination with the straw-freezing method using dry ice produced the best post-thaw quality parameters of boar semen. Combinations of glycerol and DMA did not enhance the cryosurvival of boar spermatozoa.