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Atomic clusters exhibit properties that fall between those found for individual atoms and bulk solids. Small boron clusters exhibit planar and quasiplanar structures, which are novel materials envisioned to serve as a platform for designing nanodevices and materials with unique physical and chemical properties. Through past research advancements, experimentalists demonstrated the successful incorporation of transition metals within planar boron rings. In our study, we used first-principles calculations to examine the structure and properties of neutral boron clusters doped with transition metals, denoted as TMBn and TMB2n, where TM = Ti, Cr, Mn, Fe, Co, Nb, or Mo and n = 8 – 10 . Our calculations show that the TMB2n structures, which involve sandwiching metal atoms between two rings (called the drum configuration), and clusters with the single ring configuration, TMBn, are stable. These clusters typically have relatively large HOMO-LUMO energy gaps, suggesting high kinetic stability and low chemical reactivity. Moreover, the clusters display interesting magnetic properties, determined not only by the metal atoms but also by the induced magnetism of the boron rings. These structures have potential applications in spintronics and sensing. This work also provides a basis for studying magnetism in the one-dimensional limit. [ABSTRACT FROM AUTHOR]

Heterostructured materials show great potential to enhance the specific capacity, rate performance and cycling lifespan of lithium-ion batteries owing to their unique interfaces, robust architectures, and synergistic effects. Herein, a polypyrrole (PPy)-coated nanotube-like Mo3S4/CoMo2S4 heterostructure is prepared by the hydrothermal and subsequent in situ polymerization methods. The well-designed nanotube-like structure is beneficial to relieve the serious volume changes and facilitate the infiltration of electrolytes during the charge/discharge process. The Mo3S4/CoMo2S4 heterostructure could effectively enhance the electrical conductivity and Li+ transport kinetics owing to the refined energy band structure and the internal electric field at the heterostructure interface. Moreover, the conductive PPy-coated layer could inhibit the obvious volume expansion like a firm armor and further avoid the pulverization of the active material and aggregation of generated products. Benefiting from the synergistic effects of the well-designed heterostructure and PPy-coated nanotube-like architecture, the prepared Mo3S4/CoMo2S4 heterostructure delivers high reversible capacity (1251.3 mAh g−1 at 300 mA g−1), superior rate performance (340.3 mAh g−1 at 5.0 A g−1) and excellent cycling lifespan (744.1 mAh g−1 after 600 cycles at a current density of 2.0 A g−1). Such a design concept provides a promising strategy towards heterostructure materials to enhance their lithium storage performances and boost their practical applications. [ABSTRACT FROM AUTHOR]

Ultrasound induced cavitation effects can dramatically affect physicochemical performance in photocatalysis as a result of enhanced mass transfer and the formation of highly active radicals under localized high temperature and pressure. The use of ultrasound facilitates a systematic control of photo-generated carrier properties within a nanostructured framework. Considerable research efforts have been directed at developing methodologies for the design of nanostructures with a high degree of precision. We provide a comprehensive overview of rational strategies in the sonochemical synthesis of photocatalysts and address the viability of controlling catalyst structural features. Research progress in sono-photocatalysis and piezo-photocatalysis is assessed, focusing on the integration of cavitation phenomena and artificial nanostructures in terms of practical application. Moreover, we evaluate current technologies used in quantitative analysis as a means of understanding the underlying mechanisms and evaluating catalyst properties predictably and reproducibly. Finally, we provide some insight into the possibilities, limitations and perspectives in this field.

Featured Application: The obtained knowledge can be useful for understanding and optimizing various technologies of nanostructured materials when fast melting processes take place. Interfacial thermal conductance (ITC) affects heat transfer in many physical phenomena and is an important parameter for various technologies. The article considers the influence of various mesoscopic effects on the ITC, such as the heat transfer through the gas gap, near-field radiative heat transfer, and changes in the wetting behavior during melting. Various contributions to the ITC of the liquid-solid interfaces in the processes of fast pre-melting and melting of metal microparticles are studied. The effective distance between materials in contact is a key parameter for determining ITC. This distance changes significantly during phase transformations of materials. An unusual gradual change in ITC recently observed during pre-melting below the melting point of some metals is discussed. The pre-melting process does not occur on the surface but is a volumetric change in the microstructure of the materials. This change in the microstructure during the pre-melting determines the magnitude of the dispersion forces, the effective distance, and the near-field thermal conductance. The knowledge gained can be useful for understanding and optimizing various technological processes, such as laser additive manufacturing. [ABSTRACT FROM AUTHOR]

[Display omitted] Nanocarrier-based drug delivery systems have been designed into various structures that can effectively prevent cancer progression and improve the therapeutic cancer index. However, most of these delivery systems are designed to be simple nanostructures with several limitations, including low stability and burst drug release features. A nano-in-nano delivery technique is explored to address the aforementioned concerns. Accordingly, this study investigated the release behavior of a novel nanoparticles-in-nanofibers delivery system composed of capsaicin-loaded alginate nanoparticles embedded in polycaprolactone-chitosan nanofiber mats. First, alginate nanoparticles were prepared with different concentrations of cationic gemini surfactant and using nanoemulsion templates. The optimized formulation of alginate nanoparticles was utilized for loading capsaicin and exhibited a diameter of 19.42 ± 1.8 nm and encapsulation efficiency of 98.7 % ± 0.6 %. Likewise, blend polycaprolactone-chitosan nanofibers were prepared with different blend ratios of their solutions (i.e., 100:0, 80:20, 60:40) by electrospinning method. After the characterization of electrospun mats, the optimal nanofibers were employed for embedding capsaicin-loaded alginate nanoparticles. Our findings revealed that embedding capsaicin-loaded alginate nanoparticles in polycaprolactone-chitosan nanofibers, prolonged capsaicin release from 120 h to more than 500 h. Furthermore, the results of in vitro analysis demonstrated that the designed nanoplatform could effectively inhibit the proliferation of MCF-7 human breast cells while being nontoxic to human dermal fibroblasts (HDF). Collectively, the prepared nanocomposite drug delivery platform might be promising for the long-term and controlled release of capsaicin for the prevention and treatment of cancer. [ABSTRACT FROM AUTHOR]

Interfacial thermal conductance (ITC) affects heat transfer in many physical phenomena and is an important parameter for various technologies. The article considers the influence of various mesoscopic effects on the ITC, such as the heat transfer through the gas gap, near-field radiative heat transfer, and changes in the wetting behavior during melting. Various contributions to the ITC of the liquid-solid interfaces in the processes of fast pre-melting and melting of metal microparticles are studied. The effective distance between materials in contact is a key parameter for determining ITC. This distance changes significantly during phase transformations of materials. An unusual gradual change in ITC recently observed during pre-melting below the melting point of some metals is discussed. The pre-melting process does not occur on the surface but is a volumetric change in the microstructure of the materials. This change in the microstructure during the pre-melting determines the magnitude of the dispersion forces, the effective distance, and the near-field thermal conductance. The knowledge gained can be useful for understanding and optimizing various technological processes, such as laser additive manufacturing.

The fast-developing field of RNA nanotechnology requires the adoption and development of novel and faster computational approaches to modeling and characterization of RNA-based nano-objects. We report the first application of Elastic Network Modeling (ENM), a structure-based dynamics model, to RNA nanotechnology. With the use of an Anisotropic Network Model (ANM), a type of ENM, we characterize the dynamic behavior of non-compact, multi-stranded RNA-based nanocubes that can be used as nano-scale scaffolds carrying different functionalities. Modeling the nanocubes with our tool NanoTiler and exploring the dynamic characteristics of the models with ANM suggested relatively minor but important structural modifications that enhanced the assembly properties and thermodynamic stabilities. In silico and in vitro, we compared nanocubes having different numbers of base pairs per side, showing with both methods that the 10 bp-long helix design leads to more efficient assembly, as predicted computationally. We also explored the impact of different numbers of single-stranded nucleotide stretches at each of the cube corners and showed that cube flexibility simulations help explain the differences in the experimental assembly yields, as well as the measured nanomolecule sizes and melting temperatures. This original work paves the way for detailed computational analysis of the dynamic behavior of artificially designed multi-stranded RNA nanoparticles.

We present a new method based on Weierstrass factorization to optimize broadband perfect absorber (BPA) made of metal-dielectric-metal elements, which is an efficient and general approximation to calculate the absorption of these subwavelength structures. With the resonant wavelengths estimated by semi-analytical equations, we design a planar BPA tiling three subunits in one unit cell and a vertical tapered BPA stacking 20 pairs of metal-dielectric layers in one unit cell. Both BPAs shows almost over 90% and wide angle absorption in the concerned range. This method can be an alternative to the traditional full vector methods in initial design.

We present a new method based on Weierstrass factorization to optimize broadband perfect absorber (BPA) made of metal-dielectric-metal elements, which is an efficient and general approximation to calculate the absorption of these subwavelength structures. With the resonant wavelengths estimated by semi-analytical equations, we design a planar BPA tiling three subunits in one unit cell and a vertical tapered BPA stacking 20 pairs of metal-dielectric layers in one unit cell. Both BPAs shows almost over 90% and wide angle absorption in the concerned range. This method can be an alternative to the traditional full vector methods in initial design. [ABSTRACT FROM AUTHOR]

Rational design on microstructure of magnetic material provides new opportunity to enhance the electromagnetic absorption performance. Herein, we demonstrate the successful preparation of spindle-cone of Fe/Fe 2 O 3 and Fe 3 O 4 samples with an average size of ∼1.2 μm, using a facile two-steps method. The well-defined spindle-cone shaped α-Fe 2 O 3 was developed first by a solvothermal route and then reduced by H 2 or NaBH 4 , respectively. The morphologies, phase compositions and magnetization of these as-prepared samples are analyzed by Field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and X-ray photoelectron spectrum (XPS) and vibrating sample magnetometer (VSM). Meanwhile, the electromagnetic (EM) absorption performance of Fe/Fe 2 O 3 and Fe 3 O 4 spindle-cones-paraffin composites with various filling ratios are also studied. The results reveal that Fe/Fe 2 O 3 with a filling ratio of 50 wt% achieves the smallest reflection loss value of −26.2 dB at a thickness of 1.4 mm. At thinner thickness (1.0 mm), the bandwidth (RL < −10 dB) equals to 4.5 GHz (13.5–18 GHz). The excellent absorption mechanism was discussed in this work, which attributed to the unique nanostructure and moderate impedance matching and EM loss ability. • Spindle-cone shaped magnetic hybrid was prepared by a simple two-steps method. • Fe 3 O 4 and Fe/Fe 2 O 3 could be achieved using different reduction regent. • The effective absorption frequency of Fe/Fe 2 O 3 absorber was up to 4.5 GHz with a thickness of 1.4 mm. • Such a spindle-cone shape attributed to the performance. [ABSTRACT FROM AUTHOR]

Introduction. The aim of the study was to assess the formation of biomimetic calcium hydroxyapatite (HAP) on the surface of different substrates. Material and Methods. Silica coated stainless steel tapes and thin polymer films (alginate, cellulose, poly lactide-co-glycolide - PLGA) deposited on hydroxyapatite scaffold were used as substrate. Supersaturated simulated body fluid (SBF) and SBF combined with Fetal Calf Serum (FCS) or Eagle’s Minimum Essential Medium (EMEM) were used as bioactive liquid medium where biomimetic nucleation of HAP occurred. Infrared spectroscopy with Fourier transformation was used to analyze the formed phases, while scanning electron microscopy indicated the morphology of nucleated phase. Results. The results of measuring the mass with volume adjustments done by the BET method showed that the thickness of the film of nucleated calcium hydroxyapatite depended on the time that samples spent soaked in SBF-in as well as the type of selected biomimetic medium. Conclusion. Biomimetic calcium hydroxyapatite is possible to produce by self nucleation on different substrates in the presence of simulating body fluid.

The development of competitive Na- and Mg-ion batteries (NIBs and MIBs) with performance comparable to Li-ion batteries is hindered by the major challenge of finding advanced electrode materials. In this work, nanostructured TiS 2 electrodes including nanosheets, nanoribbons and nanotubes are shown by first principles calculations to achieve improved Na and Mg ion diffusion as compared with the bulk phase. Comparative studies between Li, Na, and Mg reveal that the diffusion kinetics of Na ions would especially benefit from the nanostructure design of TiS 2 . More specifically, the Na ion diffusivity turns out to be considerably higher than Li ion diffusivity, which is opposite to that observed in bulk TiS 2 . However, in the case of Mg ions, fast diffusion is still beyond attainment since a relatively high degree of interaction is expected between Mg and the S atoms. Edge-induced modifications of diffusion properties appear in both Na and Mg ions, while the mobility of Li ions along the ribbon edges may not be as appealing. Effects of the curvature of nanotubes on the adsorption strength and ion conductivity are also explored. Our results highlight the nanostructure design as a rich playground for exploring electrodes in NIBs and MIBs. [ABSTRACT FROM AUTHOR]

A rational design and selection of electrocatalytic cathode host materials are significant to achieve sustainable, efficient and stable catalysis towards H 2 O 2 electroreduction. Herein, we described a facile synergetic strategy to generate a novel free-standing electrode (Pd-Co 3 O 4 /3D RGO@polyimide (PI) foam, PCRP) with well-developed porous and hollow structure, which derived from cobalt-based MOFs (ZIF-67) as an advanced Pd host, rooting on the 3D conductive graphene/PI foam to realize the significant promotion towards H 2 O 2 electroreduction. Such 3D hollow structure design not only offers a high specific area to develop a number of exposed catalytic activity sites but also restricts the aggregation of nanoparticle catalysts within catalysis. Utilizing the electrode structural advantages and reducing the particle diameter of noble metal catalysts to improve the catalytic performance was possible. When evaluated as a co-catalyst for H 2 O 2 electroreduction, the as-developed electrode displayed an optimized reduction current density of 962 mA·cm−2 at −0.8 V in alkaline due to the synergetic influence of Pd nanoparticles and Co 3 O 4 hollow cages. Notably, the loading of noble metal on the PCRP electrode was only close to 2.0 wt% in Pd-Co 3 O 4 hybrids. What's more, the obtained PCRP electrode also exhibited robust stability, low apparent activation energy (9.071 kJ·mol−1), good reproducibility and repeatability (903 mA·cm−2after 1000 cycles with a 0.0058% current density decay per cycle at −0.8 V) superior to that of single Co 3 O 4 nanoparticles or Co 3 O 4 /3D RGO hybrids with simple configuration, implying its great promise for novel energy transformation systems. [Display omitted] • A Pd-Co 3 O 4 /3D RGO@polyimide (PCRP) electrode was successfully developed. • Hollow structure Co 3 O 4 derived from MOFs as Pd host supported on graphene substrate. • The electrode presented characteristics of small particle diameter and low loading of Pd. • The synergism of structure and constituent promoted electrocatalytic performance. • The electrode exhibited excellent stability, reproducibility, low apparent activation energy. [ABSTRACT FROM AUTHOR]

• A new formation strategy of yolk-shell structured nanospheres was proposed. • Yolk-shell nanospheres with tunable compositions of yolk and shell parts were synthesized. • Unique structured iron oxide-C nanospheres showed excellent lithium-ion storage performances. Yolk-shell structure architecture is considered to be important in the fields that requires nanostructured designs such as energy storage systems. In particular, the internal and external structures, as well as compositions of yolk-shell materials, should be controllable in wide ranges to improve their properties for efficient applications in various fields. In this study, a new and general strategy to fabricate yolk-shell nanospheres with tunable compositions of yolk and shell parts under mild vacuum conditions is proposed. The melted metal salt is infiltrated in the void space of the hollow porous carbon nanospheres to form a yolk-shell structure under vacuum conditions, resulting in a yolk-shell structure with the configuration of a transition metal oxide (TMO)@void@C after a decomposition process under a vacuum. Yolk-shell nanospheres with configurations of TMO@void@TMO-C and TMO-C@void@TMO-C are also synthesized by controlling the vacuum degree for the infiltration of metal salt. Iron oxide, nickel oxide, and multicomponent materials are applied to confirm the applicability of the suggested method. This method facilitated in the tuning of the internal and external compositions was validated using various supporting data. The unique structured nanospheres with a configuration of FeO x -C@void@C showed an excellent lithium-ion storage performance. [ABSTRACT FROM AUTHOR]

• 3D network structure g-C 3 N 4 assembled by nanorods (3D g-C 3 N 4 NR) was fabricated via a chemical tailoring route. • 3D g-C 3 N 4 NR increases the specific surface area and accelerates the charge carrier transfer kinetics. • The visible-light photocatalytic performance of 3D g-C 3 N 4 NR has been greatly improved. Bulk g-C 3 N 4 has suffered from its low specific surface area and high recombination of photogenerated electron-hole pairs. Herein, three-dimensional network structure g-C 3 N 4 assembled by nanorods (3D g-C 3 N 4 NR) was successfully fabricated via a chemical tailoring route. The as-prepared 3D g-C 3 N 4 NR exhibits lager specific surface areas (6.7 times of bulk g-C 3 N 4) and faster charge carrier transfer kinetics. Hence, the visible-light photocatalytic activities for degradation of phenol and hydrogen evolution over 3D g-C 3 N 4 NR are evidently enhanced, 4.3 and 5.9 times as high as that of bulk g-C 3 N 4 , respectively. Briefly, this work throws light on structural tuning of carbon nitride polymer photocatalysts for improved solar energy capture and conversion. [ABSTRACT FROM AUTHOR]

Abstract We demonstrate design of Cu/Mo nanocomposite thin films with bicontinuous intertwined morphologies for high strength and plastic deformability. Through co-sputtering Cu and Mo at different temperatures, nanocomposites with lateral and random concentration modulations (LCMs and RCMs) were fabricated. Ligament size and coherency of the Cu/Mo interfaces was also controlled via the deposition conditions. It was discovered that nanocomposites with LCM structure and coherent interfaces have high strength but limited deformability. Enhanced deformability was achieved when the interface was altered to semi-coherent, although plasticity was localized in kink bands. The RCM structure design with semi-coherent interfaces showed an excellent combination of high flow strength and plastic deformability due to suppression of shear and kink bands. Graphical abstract Unlabelled Image Highlights • A novel approach in addressing the strength-deformability trade-off through morphological and interface design in metallic nanocomposites is presented. • Cu-Mo nanocomposites with tailorable morphology and interface properties have been fabricated by co-sputtering two immiscible metals at high temperatures. • The bicontinuous intertwined with semi-coherent Cu-Mo interfaces provides an unprecedented combination of high strength and enhanced plastic deformability. [ABSTRACT FROM AUTHOR]