The creation of core–shell particles is attracting a great deal of interest because of the diverse applicability of these colloidal particles; e.g., as building blocks for photonic crystals, in ...multi‐enzyme biocatalysis, and in drug delivery. This review presents the state‐of‐the‐art in strategies for engineering particle surfaces, such as the layer‐by‐layer deposition process (see Figure), which allows fine control over shell thickness and composition.
The creation of core–shell particles is attracting a great deal of interest because of the diverse applicability of these colloidal particles; e.g., as building blocks for photonic crystals, in multi‐enzyme biocatalysis, and in drug delivery. This review presents the state‐of‐the‐art in strategies for engineering particle surfaces, such as the layer‐by‐layer deposition process (see Figure), which allows fine control over shell thickness and composition.
Fluorescent particles are routinely used to probe biological processes. The quantum properties of single spins within fluorescent particles have been explored in the field of nanoscale magnetometry, ...but not yet in biological environments. Here, we demonstrate optically detected magnetic resonance of individual fluorescent nanodiamond nitrogen-vacancy centres inside living human HeLa cells, and measure their location, orientation, spin levels and spin coherence times with nanoscale precision. Quantum coherence was measured through Rabi and spin-echo sequences over long (>10 h) periods, and orientation was tracked with effective 1° angular precision over acquisition times of 89 ms. The quantum spin levels served as fingerprints, allowing individual centres with identical fluorescence to be identified and tracked simultaneously. Furthermore, monitoring decoherence rates in response to changes in the local environment may provide new information about intracellular processes. The experiments reported here demonstrate the viability of controlled single spin probes for nanomagnetometry in biological systems, opening up a host of new possibilities for quantum-based imaging in the life sciences.
It is generally impossible to probe a quantum system without disturbing it. However, it is possible to exploit the back action of quantum measurements and strong couplings to tailor and protect the ...coherent evolution of a quantum system. This is a profound and counterintuitive phenomenon known as quantum Zeno dynamics. Here we demonstrate quantum Zeno dynamics with a rubidium Bose-Einstein condensate in a five-level Hilbert space. We harness measurements and strong couplings to dynamically disconnect different groups of quantum states and constrain the atoms to coherently evolve inside a two-level subregion. In parallel to the foundational importance due to the realization of a dynamical superselection rule and the theory of quantum measurements, this is an important step forward in protecting and controlling quantum dynamics and, broadly speaking, quantum information processing.
Strong many-body interactions in solids yield a host of fascinating and potentially useful physical properties. Here, from angle-resolved photoemission experiments and ab initio many-body ...calculations, we demonstrate how a strong coupling of conduction electrons with collective plasmon excitations of their own Fermi sea leads to the formation of plasmonic polarons in the doped ferromagnetic semiconductor EuO. We observe how these exhibit a significant tunability with charge carrier doping, leading to a polaronic liquid that is qualitatively distinct from its more conventional lattice-dominated analogue. Our study thus suggests powerful opportunities for tailoring quantum many-body interactions in solids via dilute charge carrier doping.
The applicability of the layer-by-layer (LbL) technique for the formation of a range of polymer-core inorganic-shell particles and inorganic hollow spheres is demonstrated. Titanium dioxide, silica, ...and Laponite nanoparticles were used as the inorganic building blocks for multilayer formation on polystyrene (PS) sphere templates. Composite organic−inorganic particles were formed by the controlled assembly of the preformed nanoparticles in alternation with oppositely charged polyelectrolytes onto PS microspheres. The influence of nanoparticle type, shape (spherical to sheetlike), and size (3−100 nm), and the diameter of the PS sphere templates (210−640 nm) on the formation of multilayer shells was examined by transmission and scanning electron microscopy. In addition, the LbL technique for coating polymer spheres has been shown to be adaptable with small variations in the coating steps used to optimize the nanoparticle coatings of the different materials. For example, the number of polyelectrolyte multilayers separating the nanoparticle layers, and the number of nanoparticle/polyelectrolyte deposition cycles were varied to generate uniformly coated nanocomposite spheres. These hybrid core−shell particles were subsequently calcined to create well-defined hollow spheres with predetermined diameters. Such hollow spheres may find application in diverse areas, ranging from photonics to fillers and pigments to microencapsulation.
The preparation of monodisperse hollow titania spheres with defined diameter, wall thickness, and crystal phase by the layer‐by‐layer templating of colloid particles and subsequent calcination (see ...Figure) is reported. A major advantage associated with this type of colloid templating is that it can be conducted from any aqueous solution. Nanometer‐level control over the sphere wall thickness is achieved by varying the number of layers deposited on the particles.
Continuous positive airway pressure (CPAP) has been used to improve gas exchange and diaphragmatic function, among others benefits. Moreover, it can be used to increase exercise tolerance and ...positively influence ventilatory function and breathing pattern (BP) during exercise. However, there is no information about the long-term effects of CPAP, as an adjunct to an inpatient cardiac rehabilitation (CR) program, on BP and heart rate variability (HRV) of patients after coronary artery bypass grafting surgery (CABG). Twenty patients were allocated to receive, after randomization, standard inpatient CR without CPAP (control group - CG) or CR with CPAP between 10 to 12 cmH.sub.2O (CPAP group - CPG) associated with the exercises. Participants were assessed preoperatively and on the discharge day, in the sitting rest position. Outcome measurements included BP variables, collected by respiratory inductive plethysmography, and HRV, collected by polar precision performance. The CPG presented lower values of percent rib cage inspiratory and expiratory contributions to tidal volume (%RCi and %RCe) at discharge time, compared to CG. No statistical differences between groups were observed for HRV variables and both groups presented lower values of these indices, compared to preoperative ones. In this context, the patients who received CPAP throughout the whole rehabilitation program were discharged with a better BP, which could indicate more synchronized breathing. CPAP did not influence cardiac autonomic modulation in the long term. Key words: CPAP; Breathing pattern; Coronary artery bypass grafting surgery; Cardiac rehabilitation; Inpatient
Optically addressable nanostructured capsules of polyelectrolyte multilayers containing gold nanoparticles are prepared via layer‐by‐layer colloid templating. The nanocomposite capsule shell, due to ...the presence of the metal nanoparticles, can be addressed with laser light in the near‐infrared (NIR) to induce morphological changes in the capsules (see Figure). Enzyme encapsulated within these capsules is released remotely and on demand with nanosecond laser pulses in the NIR, while retaining its activity.
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