Synthesis of Multilayered Star‐Shaped B6O Particles Using the Seed‐Mediated Growth Method

In this study, we introduce a simple and effective seed‐mediated growth method (SMGM) for the controlled synthesis of boron suboxide powder. By employing starting powders with different concentrations and adding boron suboxide seeds with a star‐like morphology, we demonstrate that B₆O ceramics that exhibit high‐level crystallinity can be synthesized using SMGM at ambient pressure conditions. The formation of multilayered star‐shaped B₆O particles via SMGM is reported for the first time.     

Graphene Oxide‐Cyclic R10 Peptide Nuclear Translocation Nanoplatforms for the Surmounting of Multiple‐Drug Resistance

Multidrug resistance resulting from a variety of defensive pathways in cancer has become a global concern with a considerable impact on the mortality associated with the failure of traditional chemotherapy. Therefore, further research and new therapies are required to overcome this challenge. In this work, a cyclic R10 peptide (cR₁₀) is conjugated to polyglycerol‐covered nanographene oxide to engineer a nanoplatform for the surmounting of multidrug resistance. The nuclear translocation of the nanoplatform, facilitated by cR₁₀ peptide, and subsequently, a laser‐triggered release of the loaded doxorubicin result in efficient anticancer activity confirmed by both in vitro and in vivo experiments. The synthesized nanoplatform with a combination of different features, including active nucleus‐targeting, high‐loading capacity, controlled release of cargo, and photothermal property, provides a new strategy for circumventing multidrug resistant cancers.     

High‐temperature strength and plastic deformation behavior of niobium diboride consolidated by spark plasma sintering

Bulk niobium diboride ceramics were consolidated by spark plasma sintering (SPS) at 1900°C. SPS resulted in dense specimens with a density of 98% of the theoretical density and a mean grain size of 6 μm. During the SPS consolidation, the hexagonal boron nitride (h‐BN) was formed from B₂O₃ on the powder particle surface and residual adsorbed nitrogen in the raw diboride powder. The room‐temperature strength of these NbB₂ bulks was 420 MPa. The flexural strength of the NbB₂ ceramics remained unchanged up to 1600°C. At 1700°C an increase in strength to 450 MPa was observed, which was accompanied by the disappearance of the secondary h‐BN phase. Finally, at 1800°C signs of plastic deformation were observed. Fractographic analysis revealed a number of etching pits and steplike surfaces suggestive of high‐temperature deformation. The temperature dependence of the flexural strength of NbB₂ bulks prepared by SPS was compared with data for monolithic TiB₂, HfB₂ and ZrB₂. Our analysis suggested that the thermal stresses accumulated during SPS consolidation may lead to additional strengthening at elevated temperatures.     

Scalable Production of Nanographene and Doping via Nondestructive Covalent Functionalization

A new method for top‐down, one‐pot, gram‐scale production of high quality nanographene by incubating graphite in a dilute sodium hypochlorite solution at only 40 °C is reported here. The produced sheets have only 4 at% oxygen content, comparable with nanographene grown by chemical vapor deposition. The nanographene sheets are covalently functionalized using a nondestructive nitrene [2+1] cycloaddition reaction that preserves their π‐conjugated system. Statistical analyses of Raman spectroscopy and X‐ray photoelectron spectroscopy indicate a low number of sp³ carbon atoms on the order of 2% before and 4% after covalent functionalization. The nanographene sheets are significantly more conductive than conventionally prepared nanographene oxide, and conductivity further increases after covalent functionalization. The observed doping effects and theoretical studies suggest sp² hybridization for the carbon atoms involved in the [2+1] cycloaddition reaction leading to preservation of the π‐conjugated system and enhancing conductivity via n‐type doping through the bridging N‐atom. These methods are easily scalable, which opens the door to a mild and efficient process to produce high quality nanographenes and covalently functionalize them while retaining or improving their physicochemical properties.     

Changes in Phenotypes and DNA Methylation of In Vitro Aging Sperm in Common Carp Cyprinus carpio

The purpose of the current study was to analyze phenotypic and functional characteristics of common carp (Cyprinus carpio) spermatozoa during in vitro aging and to investigate whether global DNA methylation is affected by sperm aging. Milt was collected from five individual males, stored in vitro on ice in a refrigerator for up to 96 h post stripping (HPS) and used to fertilize eggs with intervals of 1, 24 and 96 h. Computer-assisted sperm analysis and a S3e Cell Sorter was employed to determine the spermatozoa phenotypic characteristics (motility, velocity, concentration and viability). In addition, pH and osmolality of the seminal fluid and the capacity of the spermatozoa to fertilize, hatching rate and health of the resulting embryos were examined at different aging times. Whole-genome bisulfite sequencing was used to compare the global and gene-specific DNA methylation in fresh and aged spermatozoa. The results demonstrated that spermatozoa aging in common carp significantly affects their performance and thus the success of artificial fertilization. The methylation level at the cytosine-phosphate-guanine (CpG) sites increased significantly with 24 HPS spermatozoa compared to the fresh group at 1 HPS and then decreased significantly at 96 HPS. A more detailed investigation of gene specific differences in the DNA methylation was hindered by incomplete annotation of the C. carpio genome in the public databases.     

Low-Temperature Synthesis of Boron Carbide Ceramics

This study has been the first to demonstrate the possibility of producing boron carbide ceramics from coarse (D = 25–150 μm) B₄C powder (which is impossible to sinter by conventional methods) through infiltration with molten silicon and subsequent treatment within the field of the controlled temperature gradient. This produces yields a composite ceramics B₄C–SiC–Si with a hardness of 26 to 35 GPa and a splitting tensile strength of 110 to 170 MPa. The influence of the velocity of movement of the temperature gradient on the structure, phase composition, and properties of the prepared composites has been studied.     

Effective Ligand Engineering of the Cu2ZnSnS4 Nanocrystal Surface for Increasing Hole Transport Efficiency in Perovskite Solar Cells

Effective engineering of surface ligands in semiconductor nanocrystals can facilitate the electronic interaction between the individual nanocrystals, making them promising for low‐cost optoelectronic applications. Here, the use of high purity Cu₂ZnSnS₄ (CZTS) nanocrystals as the photoactive layer and hole‐transporting material is reported in low‐temperature solution‐processed solar cells. The high purity CZTS nanocrystals are prepared by engineering the surface ligands of CZTS nanocrystals, capped originally with the long‐chain organic ligand oleylamine. After ligand removal, CZTS nanocrystals show substantial improvement in photoconductivity and mobility, displaying also an appreciable photoresponse in a simple heterojunction solar cell architecture. More notably, CZTS nanocrystals exhibit excellent hole‐transporting properties as interface layer in perovskite solar cells, yielding power conversion efficiency (PCE) of 15.4% with excellent fill factor (FF) of 81%. These findings underscore the importance of removing undesired surface ligands in nanocrystalline optoelectronic devices, and demonstrate the great potential of CZTS nanocrystals as both active and passive material for the realization of low‐cost efficient solar cells.     

Weighted average indoor positioning algorithm that uses LEDs and image sensors

We propose a weighted average indoor positioning algorithm, which is an improved version of the M.S. Rahman’s algorithm, for the calculation of unknown positions in a visible light communication system consisting of light-emitting diodes (LEDs) and image sensors. The algorithm considers the LED illumination intensity as a key factor, and the generalized Lambert illumination model is adopted to estimate the LED illumination intensity of each pixel in the images obtained at the sensors. The LED illumination intensity is normalized as a weighting factor, following the determination of the center position of the LED image. Simulations showed that the average signal-to-noise ratio in our positioning system was 19.3 dB. The simulation results also showed that the root mean square positioning error was reduced from 6.6 to 3.7 cm when the resolution of the image sensor was 3000 pixels per cm, which is comparable to the error in the widely used M.S. Rahman’s algorithm. The distance between the centers of the lenses and the focal lengths of the lenses also affects the positioning error. After the simulations, the relationship between the positioning error and the lens distance or focal length is deduced. It is observed that this algorithm has lesser positioning errors than the M.S. Rahman’s algorithm.     

A New Support Film for Cryo Electron Microscopy Protein Structure Analysis Based on Covalently Functionalized Graphene

Protein adsorption at the air–water interface is a serious problem in cryogenic electron microscopy (cryoEM) as it restricts particle orientations in the vitrified ice-film and promotes protein denaturation. To address this issue, the preparation of a graphene-based modified support film for coverage of conventional holey carbon transmission electron microscopy (TEM) grids is presented. The chemical modification of graphene sheets enables the universal covalent anchoring of unmodified proteins via inherent surface-exposed lysine or cysteine residues in a one-step reaction. Langmuir–Blodgett (LB) trough approach is applied for deposition of functionalized graphene sheets onto commercially available holey carbon TEM grids. The application of the modified TEM grids in single particle analysis (SPA) shows high protein binding to the surface of the graphene-based support film. Suitability for high resolution structure determination is confirmed by SPA of apoferritin. Prevention of protein denaturation at the air–water interface and improvement of particle orientations is shown using human 20S proteasome, demonstrating the potential of the support film for structural biology.     

Mussel-inspired multifunctional coating for bacterial infection prevention and osteogenic induction

Bacterial infection and osteogenic integration are the two main problems that cause severe complications after surgeries. In this study, the antibacterial and osteogenic properties were simultaneously introduced in biomaterials, where copper nanoparticles(Cu NPs) were generated by in situ reductions of Cu ions into a mussel-inspired hyperbranched polyglycerol(MI-h PG) coating via a simple dip-coating method.This hyperbranched polyglycerol with 10 % catechol groups’ modification presents excellent antifouling property, which could effectively reduce bacteria adhesion on the surface. In this work, polycaprolactone(PCL) electrospun fiber membrane was selected as the substrate, which is commonly used in biomedical implants in bone regeneration and cardiovascular stents because of its good biocompatibility and easy post-modification. The as-fabricated Cu NPs-incorporated PCL membrane [PCL-(MI-h PG)-Cu NPs]was confirmed with effective antibacterial performance via in vitro antibacterial tests against Staphylococcus aureus(S. aureus), Escherichia coli(E. coli), and multi-resistant E. coli. In addition, the in vitro results demonstrated that osteogenic property of PCL-(MI-h PG)-Cu NPs was realized by upregulating the osteoblast-related gene expressions and protein activity. This study shows that antibacterial and osteogenic properties can be balanced in a surface coating by introducing Cu NPs.