Palladium nanoparticles (PdNPs) have been synthesized using n-alkylamines (C n -NH 2 ) as stabilizing ligands. The NP size and distribution were controlled by varying the initial mole ratio of PdCl 2 /C n -NH 2 and carbon chain lengths of C n -NH 2 including hexylamine (C 6 -NH 2 ), dodecylamine (C 12 -NH 2 ), and octadecylamine (C 18 -NH 2 ). The average PdNP sizes were 20 ( 2.0, 6.0 ( 0.8, 5.6 ( 0.8, 6.5 ( 0.9, and 5.2 ( 0.8 nm prepared with 1:7 PdCl 2 /C 6 -NH 2 , 1:7 PdCl 2 /C 12 -NH 2 , 1:7 PdCl 2 /C 18 -NH 2 , 1:5 PdCl 2 /C 18 -NH 2 , and 1:9 PdCl 2 /C 18 -NH 2 , respectively. The particle size decreased with the increase in the carbon chain length of C n -NH 2 . The as-synthesized n-alkylamine stabilized PdNPs (C n -NH 2 -PdNPs) were fully characterized by transmission electron microscopy, X-ray powder diffraction, UV-visible absorption spectroscopy, infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), proton nuclear magnetic resonance ( 1 H NMR) spectroscopy, thermogravimetric analysis, graphite furnace atomic absorption spectrometry, and mass spectrometry. The interaction of C 18 -NH 2 with PdNPs was verified by IR, XPS, and 1 H NMR spectra, demonstrating that the amine functionalities were successfully linked to the Pd core surfaces. The PdNPs are soluble and stable in apolar solvents such as benzene, chloroform, n-hexane, and toluene. The electrochemical reactions between CH 4 and C n -NH 2 -PdNPs on Pd electrodes were studied by cyclic voltammetry and chronoamperometry. These PdNPs reacted readily and produced good response to CH 4 at ambient conditions. The sensitivity to CH 4 depends on the PdNPs prepared from various n-alkyl chain lengths of C n -NH 2 and also the mole ratio of PdCl 2 /C n -NH 2 . It was determined that PdNPs synthesized from 1:7 PdCl 2 /C 18 -NH 2 displayed the best electrocatalytic oxidization of CH 4 . The C 18 -NH 2 -PdNP (5.6 nm) modified Pd electrode could be used repeatedly and had a stable and reproducible response to CH 4 .

Natural biological surfaces such as lotus leaves and water striders have micro- and nanostructures and low-surface-energy materials, possessing excellent superhydrophobicity. It has become an important research topic to construct bionic superhydrophobic surfaces and explore their functional applications. This paper reviews the research progress on the fabrication and applications of superhydrophobic surfaces with micro/nanostructures. The techniques used for fabricating superhydrophobic surfaces, including the template method, nano-imprinting technique, laser-treatment, plasma treatment, electrospinning technique, solution-chemical etching method, electrochemical technique, phase separation method and sol–gel process, were introduced. Also, the diverse functional applications of superhydrophobic surfaces such as self-cleaning, anti-icing, oil–water separation, anti-corrosion and drag reduction were summarised. It is believed that green fabrication will become the future development direction of superhydrophobic surfaces. Further exploration for the superhydrophobic surfaces with mechanical stability and durability will be expected to expand the application prospect and commercial value of superhydrophobic surfaces.

[Tyr(6)]-gamma2-MSH(6-12) with a short effecting time of about 20 min is one of the most potent rMrgC receptor agonists. To possibly increase its potency and metabolic stability, a series of analogues were prepared by replacing the Tyr(6) residue with the non-canonical amino acids 3-(1-naphtyl)-L-alanine, 4-fluoro-L-phenylalanine, 4-methoxy-L-phenylalanine and 3-nitro-L-tyrosine. Dose-dependent nociceptive assays performed in conscious rats by intrathecal injection of the MSH peptides showed [Tyr(6)]-gamma2-MSH(6-12) hyperalgesic effects at low doses (5-20 nmol) and analgesia at high doses (100-200 nmol). This analgesic activity is fully reversed by the kyotorphin receptor-specific antagonist Leu-Arg. For the two analogues containing in position 6, 4-fluoro-L-phenylalanine and 3-nitro-L-tyrosine, a hyperalgesic activity was not observed, while the 3-(1-naphtyl)-L-alanine analogue at 10 nmol dose was found to induce hyperalgesia at a potency very similar to gamma2-MSH(6-12), but with longer duration of the effect. Finally, the 4-methoxy-L-phenylalanine analogue (0.5 nmol) showed greatly improved hyperalgesic activity and prolonged effects compared to the parent [Tyr(6)]-gamma2-MSH(6-12) compound.

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