RNA duplex regions are often involved in tertiary interactions and protein binding and thus there is great potential in developing ligands that sequence-specifically bind to RNA duplexes. We have developed a convenient synthesis method for a modified peptide nucleic acid (PNA) monomer with a guanidine-modified 5-methyl cytosine base. We demonstrated by gel electrophoresis, fluorescence and thermal melting experiments that short PNAs incorporating the modified residue show high binding affinity and sequence specificity in the recognition of an RNA duplex containing an internal inverted Watson-Crick C-G base pair. Remarkably, the relatively short PNAs show no appreciable binding to DNA duplexes or single-stranded RNAs. The attached guanidine group stabilizes the base triple through hydrogen bonding with the G base in a C-G pair. Selective binding towards an RNA duplex over a single-stranded RNA can be rationalized by the fact that alkylation of the amine of a 5-methyl C base blocks the Watson–Crick edge. PNAs incorporating multiple guanidine-modified cytosine residues are able to enter HeLa cells without any transfection agent.

Hierarchically porous CuO architectures were successfully fabricated via copper basic carbonate precursor obtained with a facile hydrothermal route. The shape of the precursor is preserved after its conversion to porous CuO architectures by calcination. The obtained CuO are systemically characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller N(2) adsorption-desorption analysis. The results reveal that hierarchical CuO microspheres are monoclinic structure and are assembled by porous single-crystal sub-microplatelets. The Brunauer-Emmett-Teller N(2) adsorption-desorption analysis indicates that the obtained CuO has a surface area of 12.0 m(2)/g with pore size of around 30 nm. The gas sensing performance of the as-prepared hierarchical CuO microspheres were investigated towards a series of typical organic solvents and fuels. They exhibit higher sensing response than that of commercial CuO powder. Their sensing properties can be further improved by loading of Ag nanoparticles on them, suggesting their potential applications in gas sensors.

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temperature, has become a promisingly alternative technology to the existing vapor-compression refrigeration due to its energy efficiency and environment friendly. [4][5][6] As the core part of magnetic refrigeration, the comprehensive performance including MCE, thermal conductivity (λ), preparation and fabrication, corrosion resistance, and thermal and magnetic field cycling stabilities for magnetocaloric materials greatly affect the performance of the magnetic refrigerator. [7,8] Pure Gd, as the benchmark magnetic refrigerant, is commonly used in the active magnetic regenerator prototypes. [9,10] In particular, Gd metal could be produced into different shapes due to its good mechanical properties, such as thin plate, sphere, and microwire, and it has been demonstrated that microwire is more desirable for realizing a higher cooling performance. [11][12][13][14][15][16] However, Gd metal also has its disadvantages such as relatively low magnetic entropy change (ΔS M ), limited availability, and expensive price that hinder its large-scale commercialization. Therefore, a great number of magnetic materials with large MCE around room temperature have been extensively explored in the past decades. [2,6,[17][18][19][20] Unfortunately, although these new materials exhibit much better MCE than that of Gd, they still have severe shortcomings such as hard preparation Magnetic refrigeration based on magnetocaloric effect (MCE) has become a promisingly alternative technology to the conventional vapor-compression refrigeration. A great number of magnetic materials have been reported to exhibit larger MCE than that of the benchmark magnetic refrigerant Gd.However, these materials still have severe shortcomings on the "Non-MCE" properties, such as hard preparation and fabrication, low thermal conductivity λ, and poor corrosion resistance and cycling stabilities, which hinder the practical application of these materials. In this paper, a novel La(Fe, Si) 13 H y / In composite which is prepared by a readily available hot pressing method is demonstrated to exhibit an outstanding comprehensive performance with durable service life in various aspects. Noteworthily, the ΔS M does not decrease but increases with increasing nonmagnetic In metal. This advantageous anomaly is related to the strengthening of the first-order itinerant electron metamagnetic transition induced by residual compression stress and surrounded constraints in the composite. The present results make La(Fe, Si) 13 H y /In composite the most attractive alternative to Gd for magnetic refrigeration. Moreover, this work also provides a feasible way to solve the serious issues toward applications for La(Fe, Si) 13 -based materials and other brittle magnetocaloric materials.

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