Thermal Stability of Skyrmion Tubes in Nanostructured Cuboids.

Magnetic skyrmions in bulk materials are typically regarded as two-dimensional structures. However, they also exhibit three-dimensional configurations, known as skyrmion tubes, that elongate and extend in-depth. Understanding the configurations and stabilization mechanism of skyrmion tubes is crucial for the development of advanced spintronic devices. However, the generation and annihilation of skyrmion tubes in confined geometries are still rarely reported. Here, we present direct imaging of skyrmion tubes in nanostructured cuboids of a chiral magnet FeGe using Lorentz transmission electron microscopy (TEM), while applying an in-plane magnetic field. It is observed that skyrmion tubes stabilize in a narrow field-temperature region near the Curie temperature (Tc). Through a field cooling process, metastable skyrmion tubes can exist in a larger region of the field-temperature diagram. Combining these experimental findings with micromagnetic simulations, we attribute these phenomena to energy differences and thermal fluctuations. Our results could promote topological spintronic devices based on skyrmion tubes.

Tröger's Base-Based Cuboid Constructed by Chiral Self-Discrimination.

Cuboid, a basic geometric structure, has been widely applied in architecture and mathematics. In chemistry, the introduction of cuboid structures always provides a specific structural shape, enhances the stability of the structure and improves the performance of materials. Herein, a simple strategy exploiting self-discrimination to construct a cuboid-stacking crystal material is proposed, in which a chiral macrocycle (TBBP) based on Tröger's base (TB) and benzophenone (BP) was synthesized as the building element of the cuboid. The cuboid is designed to be transformable compared with cuboid structures in previous work. For this reason, it is considered that the cuboid-stacking structure can be transformed through external stimulation. Iodine vapor is selected as the external stimulus to transform the cuboid-stacking structure due to the favorable interaction between iodine and the cuboid. The changes in the stacking mode of TBBP is studied by single-crystal X-ray diffraction (SCXRD) and powder X-ray diffraction (PXRD). To our surprise, this Tröger's base-based cuboid shows strong iodine adsorption capacity up to 3.43 g g-1 and exhibits potential as a crystal material for iodine adsorption.

Elite Tennis Players Experiencing High-Arched Supination and Cuboids Dropped Foot Syndromes in Daily Normal Gait.

Many studies have focused on the plantar pressure characteristics of specific movements and footwork in tennis. However, little research has been conducted for exploring the foot characteristics among tennis professionals' daily habitual paces. This study aims to examine the pressure profiles associated with foot posture and balance abilities of elite tennis players during normal gait to understand how foot loading patterns result from habitual paces that may be derived from intensive tennis training and competition. A cross-sectional comparative study is conducted on 95 male college elite tennis players (mean age: 20.2 ± 1.2 years) and 100 male recreational tennis players (mean age: 19.8 ± 0.9 years). Bipedal plantar pressure distributions (PPDs) associated with arch index (AI) and centers of gravity balance are explored through the plantar pressure device. The foot posture is estimated to determine the rearfoot postural alignment. During the midstance phase of walking with a normal gait, the bipedal AI values of the elite group are significantly lower, indicating that they have high-arched feet. Additionally, the elite group experienced higher PPDs at the lateral regions of their longitudinal arches and heels and relatively lower PPDs at the medial portions of both feet. Rearfoot postural alignment resonance analysis of the PPDs suggests that the elite group experienced foot supination associated with cuboid dropped. Moreover, the right foot bears heavier centers of gravity balance in the present study. The elite tennis players in the study are categorized as having high-arched supination with cuboids dropped when performing daily habitual paces. This finding warrants further investigation into the correlation between possible injuries and daily habitual paces that may result from tennis' intensive training and competition.

A Tunable Triple-Band Near-Infrared Metamaterial Absorber Based on Au Nano-Cuboids Array.

In this article, we present a design for a triple-band tunable metamaterial absorber with an Au nano-cuboids array, and undertake numerical research about its optical properties and local electromagnetic field enhancement. The proposed structure is investigated by the finite-difference time domain (FDTD) method, and we find that it has triple-band tunable perfect absorption peaks in the near infrared band (1000-2500 nm). We investigate some of structure parameters that influence the fields of surface plasmons (SP) resonances of the nano array structure. By adjusting the relevant structural parameters, we can accomplish the regulation of the surface plasmons resonance (SPR) peaks. In addition, the triple-band resonant wavelength of the absorber has good operational angle-polarization-tolerance. We believe that the excellent properties of our designed absorber have promising applications in plasma-enhanced photovoltaic, optical absorption switching and infrared modulator optical communication.

Enzymatic Conversion of Oleuropein to Hydroxytyrosol Using Immobilized ß-Glucosidase on Porous Carbon Cuboids.

In the present study, we developed novel ß-glucosidase-based nano-biocatalysts for the bioconversion of oleuropein to hydroxytyrosol. Using non-covalent or covalent immobilization approaches, ß-glucosidases from almonds and Thermotoga maritima were attached for the first time on oxidized and non-oxidized porous carbon cuboids (PCC). Various methods were used for the characterization of the bio-nanoconjugates, such as Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and fluorescence spectroscopy. The oxidation state of the nanο-support and the immobilization procedure play a key role for the immobilization efficiency or the catalytic activity of the immobilized ß-glucosidases. The nano-biocatalysts were successfully used for the hydrolysis of oleuropein, which leads to the formation of its bioactive derivative, hydroxytyrosol (up to 2.4 g L-1), which is a phenolic compound with numerous health benefits. The bio-nanoconjugates exhibited high thermal and operational stability (up to 240 hours of repeated use), which indicated that they are efficient tools for various bio-transformations.

The synthesis of Ag-coated tetrapod gold nanostars and the improvement of surface-enhanced Raman scattering.

In this work, the novel tetrapod gold nanostars with four specific numbers of sharp tips were synthesized with good uniformity, high yield and chemical stability. The size of tetrapod gold nanostars has been increased effectively by increasing the amount of HAuCl4 or DEA added to the reaction solution, and the corresponding in-plane localized surface plasmon resonance (LSPR) band can shift from 700 to 1100 nm. In order to combine the advantages of different metals, the Ag-coated tetrapod gold nanostars were prepared with different Ag coating thicknesses by increasing the volume of AgNO3. With the increase of Ag coating thickness, the morphology of the nanoparticles has changed from gold nanostars with four sharp tips to bimetallic cuboids with four sharp tips and finally to crore-shell cuboids completely. The surface-enhanced Raman scattering (SERS) activity of Ag-coated tetrapod gold nanostars has also been improved with the different Ag coating thicknesses. Combined the tip effect and the enhancement effect of Ag, the SERS activity has the strongest enhancement when the four sharp tips of tetrapod gold nanostars are not completely coated by the Ag layer but still exposed to the outsides. For tetrapod gold nanostars with larger size to grow Ag-coated tetrapod gold nanostars, the bimetallic cuboids with four sharp tips nanostructure have the biggest SERS enhancement factor (EF) of 1.73 × 106 for Rhodamine 6G (R6G), making it an ideal candidate in SERS-based sensing application.

Synthesis of Si-Induced MnO/Mn2SiO4@C Cuboids as High-Performance Anodes for Lithium-Ion Batteries.

The exploration of anode materials of lithium-ion batteries (LIBs) is still a great challenge because of their low electrical conductivity and poor durability. Transition-metal oxides are proposed as a potential alternative, even though their dimension and structure greatly affect their electrochemical properties. In this study, MnO/Mn2SiO4@C cuboids were prepared via the polymerization-pyrolysis process. Larger MnCO3 precursor particles embedded into a monolithic carbon framework and formed smaller nanoparticles owing to the inducing effect of Si element in phthalocyanino silicon (SiPc), giving MnO/Mn2SiO4@C cuboids. The micron-scaled cuboid composite can lead to higher tap density and greater electrical performance due to lower interparticle resistance. Therefore, the as-prepared MnO/Mn2SiO4@C electrode exhibits stable specific capacities of 585.9 and 423.9 mA h g-1 after 1000 discharge/charge cycles at 1 and 2 A g-1, respectively. Meanwhile, an excellent rate capacity of 246.3 mA h g-1 was achieved even at 30 A g-1. Additionally, this facile and economical strategy to improve electrode performance provides a commercially feasible way for the construction of high-performance LIBs.

Green tide deactivation with layered-structure cuboids of Ag/CaTiO3 under UV light.

In this work, an alternative to deactivate noxious green tide Tetraselmis suecica in the short-term is proposed by employing Perovskite-like cube-shaped, crystalline CaTiO3 semiconductors functionalized with atomic silver nanoparticles. CaTiO3 was prepared by a microwave-assisted hydrothermal method and then Ag(0)NPs (1 wt% of CaTiO3), were added by the photoreduction method. The XRD results show that crystalline CaTiO3 has an orthorhombic unit cell with a Perovskite-like structure. Images obtained by FESEM and HRTEM microscopies show well-faceted CaTiO3 rectangular prismatic morphology functionalizated with silver nanoparticles ≈ 13.5 nm. XPS and EDS-FESEM has confirmed the composition of CaTiO3 and silver occurring mainly as reduced metal. The UV inactivation of noxious T. suecica with Ag/CaTiO3 nanocomposites formed on bare materials results in complete deactivation of the algae in 12 min. The direct contact between harmful algae and Ag/CaTiO3 nanocomposite is necessary to deactivate the algae and inhibits algae viability.