The propagation of the longitudinal waves in a single-walled carbon nanotube (SWCNT) considering the effects of thermoelastic damping is investigated in this Letter. The cylindrical shell is considered and the Donnell–Mushtari–Vlasov approach is utilised. The thermoelasticity governing equations are derived based on thin shell theory. Analytical expressions for the quality factor (Q-factor) of thermoelastic damping are presented for plane stress and strain conditions. The numerical results are presented to investigate the influence of some parameters on Q-factor of thermoelastic damping, such as the length of a nanotube, nanotube thickness and the ambient temperature. In addition, the dispersion curve of the longitudinal waves propagation in the SWCNT under the effects of thermoelastic damping is plotted. It can be seen that the Q-factor is proportional to the length and thickness of the SWCNT. It means that the increase in both length and radial thickness of the nanotube makes the Q-factor increase. For the final observation, it should be noted that the ambient temperature has an inverse effect on the Q-factor for the SWCNT. It means that the increase in ambient temperature makes the Q-factor decrease. These results can be helpful in the design of resonators and nanodevices.

The Fe₃O₄ nanoparticles and Fe₃O₄/Halloysite nanotubes (HNTs) were synthesised by the co-precipitation method and Fe₃O₄/HNTs/polypyrrole (PPy) nanocomposites were synthesised by in situ polymerisation of pyrrole monomers on the surface of the Fe₃O₄/HNTs. The scanning electron microscopy images showed the uniform structure of nanocomposites. The Fourier transform infrared spectra revealed the characteristic peaks of Halloysite and PPy. The Fe₃O₄/HNTs/PPy nanocomposite exhibits a saturated magnetisation of 6.7 emu/g. The microwave absorption properties of Fe₃O₄/HNTs/PPy nanocomposites were investigated in the 8–12 GHz (X-band) range. The value of the minimum reflection loss was obtained − 26.2 dB at 11 GHz for the 3 mm thickness nanocomposite. The results showed the absorbing bandwidth below − 10 dB was broadened to 2.3 GHz.

Silica-encapsulated waterborne flaky aluminium (SEWFA) is widely used in industrial fields, but its corrosion hampers its long-term use. Herein, a sol–gel method was used to prepare graphene oxide (GO)-modified SEWFA (GO-SEWFA). The oxygen-containing functional groups of GO can react with tetraethyl orthosilicate to form a well-dispersed silica/GO matrix on the surface of GO-SEWFA. The hydrogen evolution results demonstrated that GO covalent bonding, combined with silica encapsulation on the surface of flaky aluminium, could effectively improve the anticorrosive performance.

Short-chain C₄H₉NH₃Br compound can be used as the surface capping to synthesise CH₃NH₃PbBr₃ perovskite nanocrystal. In this work, employed as the surface ligand of CH₃NH₃PbBr₃ perovskite thin films, the influence of C₄H₉NH₃Br additive on the morphology and optical properties of CH₃NH₃PbBr₃ thin films were studied systematically. As the doping ratio of C₄H₉NH₃Br compound increases, the growth of CH₃NH₃PbBr₃ crystal grain can be controlled, and optical properties of CH₃NH₃PbBr₃ thin films can be improved. The best quality can be obtained with 20% of C₄H₉NH₃Br. Finally, the optimal sintering conditions of CH₃NH₃PbBr₃ perovskite thin films are determined at 80°C, 4 min.

The main purpose of this Letter was to develop and optimise recombinant hepatitis B antigen-loaded chitosan nanoparticles (rHBsAg-CS NPs) as a new adjuvant for hepatitis B vaccine through designing by response surface methodology (RSM). The NPs were prepared by employing ionic gelation technique. RSM was utilised by selecting the independent variablesincluding the concentration of CS, tripolyphosphate and antigen concentration as well as pH and homogenisation speed to obtain maximum encapsulation efficiency (EE) and loading capacity (LC). EE and LC of the optimised preparation were 93.2 ± 1.1 and 25.6 ± 1.38%, respectively. Optimised NPs showed spherical shape, particle size of 187 ± 14 nm and positive zeta potential (+31.3 ± 1.5 mV). In vitro release profile of optimised formulation revealed an initial burst, followed by a slow sustained antigen release. Cell viability assay indicated that the toxicity of NPs was concentration-dependent. SDS-PAGE analysis confirmed the structural stability and integrity of the released antigen. ELISA and Ouchterlony double immunodiffusion tests of released antigen showed that the antigenicity was preserved during the process of NP formation.

The present work reports the realisation of high-quality crystalline CdS/Mn₃O₄ (CM) nanocomposites by a simple cost-effective chemical method in air atmosphere. The authors have performed theoretical calculations and experimental analysis in order to understand the synthesised nanocomposites. X-ray diffraction results showed that the CM nanocomposites were cubic and orthorhombic mixed structure which is in good agreement with the theoretical studies. Field emission scanning electron microscopy images of CM confirmed the formation of well distributed nanocomposites. The outcomes of DFT calculations provide results for the bandgap calculation of pure CdS, Mn₃O₄ and the CM nanocomposites. Photoluminescence studies with interesting visible light absorption demonstrated the great potentiality of the as-synthesised nanocomposites towards photocatalytic applications that could be a detailed research scope for the authors’ future studies.

Although a microfluidic neuronal culture technique that utilised a microchannel structure to generate a motor nerve organoid consisted of neurospheres and fascicles of motor neuronal axons derived from human induced pluripotent stem cells (iPSCs) was reported recently, the lengths of the axonal fascicles were limited to less than 1 cm, which corresponded to the microchannel length. In this study, the authors fabricated microfluidic devices composed of a polydimethylsiloxane chip with a glass substrate and 20-mm-long and 150-μm-wide microchannels to obtain centimetre-long axonal fascicles. They investigated the effects of microchannel height on fascicle length by using three different microchannel heights (120, 150, and 220 μm), neurospheres containing 80,000 motor neuronal cells derived from a human iPSCs cell line (409B2), and N2B27 medium. Maximum and average fascicle lengths of 2 and 1.25 cm, respectively, were successfully achieved with 150-μm-high microchannels. The fascicles grew in length, with an increase in the number of days spent in the culture (ranging from 0.44 to 0.60 mm per day), growing to over 1 cm around the 23rd day of culture. The difference in fascicle length obtained with 120-μm and 150-μm-high microchannels suggests that height significantly affects the length of the axonal fascicle of the nerve organoid.

The flower-like and hexagonal flake-like ZnO microstructures were synthesised by a microwave method using ammonia water and sodium hydroxide as precipitant, respectively. The products were characterised by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction and photoluminescence. The photocatalytic activity of the flower-like and hexagonal flake-like ZnO microstructures was evaluated by the degradation of methyl orange (MO) under ultraviolet (UV) light irradiation. The results indicated that the best flower-like ZnO microstructure was obtained when the experimental conditions were [Zn²⁺] = 0.025 mol l⁻¹, [Zn²⁺]:[NH₃·H₂O] = 1:1.5, microwave power = 231 W. Under the same reaction conditions, hexagonal flake-like ZnO can be obtained by using sodium hydroxide as precipitant. The MO in aqueous solution was completely eliminated by flower-like ZnO after 120 min of UV light irradiation. Under identical conditions, the degradation of MO in aqueous solution was completely finished within 150 min in the presence of hexagonal flake-like ZnO. The flower-like ZnO sample showed an enhanced photocatalytic activity compared with the hexagonal flake-like ZnO for the MO degradation, which could be attributed to the presence of more active centres and hence can have more opportunities to contact with MO molecules.

To investigate the influence of graphene on the photocatalytic activity of bismuth ferrite (BiFeO₃), BiFeO₃ and flaky BiFeO₃@graphene were prepared through the hydrothermal-synthesis process. The as-prepared particles were characterised by XRD, TGA, SEM, X-ray photoelectron spectroscopy, and PL measurements. The results show that the BiFeO₃ nanoparticles have a microstructure and homogeneously attached to graphene sheets. Moreover, the flaky BiFeO₃@graphene composites exhibited higher photocatalytic efficiency than pure BiFeO₃, especially under visible light irradiation. The synergistic effects of graphene and BiFeO₃ of composites were proposed to guide the further improvement of their photocatalytic activity.

Modifying the morphology of nanostructures and its influence on the features of the tailored nanoparticles (NPs) has attracted a great deal of interest. In this research, the morphological effect on magnetic properties of the bare or modified NPs was investigated. Bare NPs were fabricated by the sol–gel route and modified NPs were prepared using hydrophilic absorbent cotton (HAC) to architect morphology of the NPs. X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transform infrared analyses confirmed that pure SrAl_1.3Fe_10.7O₁₉ NPs were synthesised based on the modified sol–gel method. Results indicated that HAC as a novel and affordable template modified the shape of the NPs. The obtained results by the diffuse reflection spectroscopy suggest that the optical performance of the NPs can be tuned by modifying the size of them. Additionally, the hysteresis loops of the vibrating sample magnetometer attested that the saturation magnetisation (M _s) of the modified NPs was elevated.

In this study, a typical MXene material, Ti₃C₂, was selected as a co-catalyst and then integrated with ZnO via a facile hydrothermal strategy. The phase composition, morphology, and photophysical properties of as-prepared samples were investigated by XRD, field emission SEM, ultraviolet–visible spectrophotometer, and fluorescence spectrophotometer, respectively. In addition, the results of the photocatalysis experiment showed that the photocatalytic activity of ZnO can be improved significantly through the hybridisation with Ti₃C₂, which arises from the inhibition of the photogenerated carriers recombination. Furthermore, the theoretical analysis indicated that the high-quantum efficiency arises from the appropriate Fermi level position of Ti₃C₂. This work demonstrated that Ti₃C₂ will show great potential for constructing novel and efficient photocatalysts.

A microfluidic chip that can realise reversible and highly selective NH₃ detection by separating NH₃ from the complex environment is fabricated for slipping NH₃ detection. The microfluidic chip consisting of the reaction unit, the gas-diffusion unit and detection unit applied the immobilised zinc tetraphenylporphyrin as the indicating material. The continuous spectrum change showed the light intensity decreased in the green range (500–550 nm). Based on the analysis of the spectrum change at 528 nm, a one-to-one relationship between the spectrum change and concentration was revealed. The reversibility of the detection process makes the detection advantageous. Also, the rapidity of the proposed method is proved by the time responses of the indicating and recovering processes. According to the 40 tests conducted for various concentrations, it was concluded that the results are stable and the entire system is reliable.

Fe₃O₄ with different shapes are reported herein to modify the glassy carbon electrode and then they are used to detect dopamine (DA), a member of the catecholamine and phenethylamine families. Cyclic voltammetry, electrochemical impedance spectroscopy, differential pulse voltammetry and linear sweep voltammetry are all chosen to characterise the sensor's performance to DA. Under the optimal conditions, the modified sensor (N-rGO/Fe₃O₄ NRs/GCE) had some good performance, followed as short response time (∼3 s), wide linear range (0.2–176 μM), low detection limit (0.05 μM, S/N = 2), good stability and reproducibility. The fabricated DA biosensor was further investigated for DA determination in human blood serum, suggesting its great potential in biological samples.

Four kinds of x wt.% phosphotungstic acid/silicon carbide (PTA/SiC) photocatalysts were prepared by impregnation method with SiC, 12-phosphotungstic acid (PTA) as raw materials. The structure of samples was characterised by X-ray diffraction, ultraviolet–visible diffuse reflectance spectra, scanning electron microscope. The photocatalytic activity of samples was evaluated by the degradation of rhodamine B (RhB) under a xenon lamp (λ≥420 nm). The results indicate that the photocatalysts not only maintained the SiC structure but also kept the Keggin structure of PTA. The 20 wt.% PTA/SiC exhibited the best photocatalytic degradation efficiency reaching up to 77% for 180 min irradiation, and the photo-degradation rate constant was determined to be 7.82 × 10⁻³ min⁻¹. In the presence of H₂O₂, the photocatalytic degradation rate of 20 wt.% PTA/SiC composites was increased to 87%, and the photodegradation reaction rate constant was 7.77 × 10⁻³ min⁻¹. According to free radical trapping experiments, it is proved that hydroxyl radical (·OH) plays an important role in photocatalysis.

In this study, using the lung cancer cells (A549) as the model cell line, the authors proposed a facile method to prepare uniform-sized cancer cell membrane (Ccm) vehicle, which was then employed to load the photothermal agent indocyanine green (ICG) for effective cancer photothermal therapy (PTT). The as-prepared Ccm/ICG was demonstrated to have a uniform particle size of around 100 nm, which was capable of targeting the A549 cells through Ccm-mediated endocytosis. As a result, the Ccm/ICG increased the cellular uptake of Ce6 into A549 cells as compared to free ICG and potentiated the PTT efficacy both in vitro and in vivo, which might be a promising drug delivery system for advanced cancer therapy.

The layered van der Waals magnetic insulator chromium bromine (CrBr₃) has excellent optical properties and it provides an interesting platform for investigating light–matter interactions. Here, we focused on its self-modulated photoluminescence (PL) spectrum. We find that there are interference fringes superposed on the PL curves due to the Fabry–Perot resonance between the front and rear interfaces of CrBr₃ flakes. Moreover, there is a huge Stokes shift between the PL spectrum and lowest absorption band, which can prevent reabsorption of PL and is a benefit for enhancing the resonant intensity of the PL spectrum. In addition, we investigate the PL spectrum variation under suppressing thermal vibration with decreasing temperature from 300 to 80 K, which shows the significant increase of PL intensity and blue shift of PL maximum peak. This work gives details of CrBr₃ self-modulated PL properties and creates opportunities for using CrBr₃ in optical devices and lasing components in future applications.