The successful application of mesoporous silica nanomaterials (MSNs) in biomedical fields requires careful consideration of their spatial dimensions, biofunctionality, specific cellular uptake efficiency, biocompatibility and targeting delivery efficacy. A deep understanding of the interactions between MSNs and biological systems is thus of significant importance. To this end, over the past few decades, studies aimed at synthesis of MSNs with controlled size, shape and surface chemistry properties and exploring the roles of these properties on in vitro and in vivo biological performance have been conducted. These studies provide new and foundational information for engineering the next generation of mesoporous silica-based nanoscale devices. This review highlights the current progress on the controlled synthesis of size, shape and surface chemistry tuneable MSNs, emphasises the roles of size, shape and surface chemistry on biological systems with a special focus on the direct comparison studies, and discusses the emerging design paradigm for building mesoporous silica-based particulate systems.

We report experimental and simulation results of capacitance of quantum well infrared photodetectors (QWIPs). We found that the QWIP capacitance displays unusual behavior as a function of voltage and frequency, deviating far from the constant geometric capacitance value. At high voltages, capacitance starts with a negative value at low frequencies, increases above zero with frequency, and eventually decays to the geometric capacitance value. The magnitude of negative capacitance exceeds the geometric capacitance by more than two orders of magnitude. Negative capacitance arises when the transient current in response to a voltage step is nonmonotonic with time. Simulation shows that this effect is due to nonequilibrium transient electron injection from the emitter resulting from the properties of the injection barrier and inertia of the QW recharging processes.

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Land use changes extensively affect soil ero-