Hollow silica nanospheres (HSN) with low densities, large interior spaces and permeable silica shells are suitable for loading enzymes in the cavity to carry out intracellular biocatalysis. The porous shell can protect the encapsulated enzymes against proteolysis and attenuate immunological response. We developed a microemulsion-templating method for confining horseradish peroxidase (HRP) in the cavity of HSN. This simple one-pot enzyme encapsulation method allows entrapping of the enzyme, which retains high catalytic activity. Compared with HRP supported on solid silica spheres, HRP@HSN with thin porous silica shells displayed better enzyme activity. The small HRP@HSN (∼50 nm in diameter), giving satisfactory catalytic activity, can act as an intracellular catalyst for the oxidation of the prodrug indole-3-acetic acid to produce toxic free radicals for killing cancer cells. We envision this kind of hollow nanosystem could encapsulate multiple enzymes or other synergistic drugs and function as therapeutic nanoreactors.

This paper reviews the AIM 2019 challenge on real world super-resolution. It focuses on the participating methods and final results. The challenge addresses the real world setting, where paired true high and low-resolution images are unavailable. For training, only one set of source input images is therefore provided in the challenge. In Track 1: Source Domain the aim is to super-resolve such images while preserving the low level image characteristics of the source input domain. In Track 2: Target Domain a set of high-quality images is also provided for training, that defines the output domain and desired quality of the superresolved images. To allow for quantitative evaluation, the source input images in both tracks are constructed using artificial, but realistic, image degradations. The challenge is the first of its kind, aiming to advance the state-of-the-art and provide a standard benchmark for this newly emerging task. In total 7 teams competed in the final testing phase, demonstrating new and innovative solutions to the problem.

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Memory devices containing the nanocrystalline Si embedded Zr-doped HfO2 high-k dielectric film, which have many advantages over the conventional non-doped high-k films, have been prepared and characterized. The memory effect was manifested by the large counterclockwise capacitance–voltage hysteresis, e.g., 2.98 V, and negative differential resistance region in the positive bias current–voltage characteristics. A large memory operation window, e.g., 0.72 V, with a long charge retention time, e.g., >10,000 s, was achieved under the proper gate stress voltages. It is a viable dielectric for future nano-size metal oxide semiconductor field effect transistors and capacitors.

Metal–oxide–semiconductor capacitors made of the nanocrystalline ruthenium oxide embedded Zr-doped HfO2 high-k film have been fabricated and investigated for the nonvolatile memory properties. Discrete crystalline ruthenium oxide nanodots were formed within the amorphous high-k film after the 950 °C postdeposition annealing step. The capacitor with the Zr-doped HfO2 high-k gate dielectric layer traps a negligible amount of charges. However, with the nanocrystalline ruthenium oxide dots embedded in the high-k film, the capacitor has a large memory window. The charge trapping capacity and the trapping site were investigated using the constant voltage stress method and the frequency-dependent capacitance–voltage measurement. The memory function is mainly contributed by the hole-trapping mechanism. Although both holes and electrons were deeply trapped to the bulk nanocrystalline RuO site, some holes were loosely trapped at the nanocrystal/high-k interface. The current–voltage and charge retention results confirmed the above-mentioned charge trapping mechanism. In summary, this kind of nanocrystal-embedded high-k dielectric has a long charge retention lifetime, which is suitable for future nanosize nonvolatile memory applications.