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This paper aims to experimentally investigate the effect of graphene nanoplatelets (GNPs) doped Al2O3 coating deposited on the surface of cemented carbide substrate using suspension high velocity oxy fuel (SHVOF) thermal spraying technique. Scanning electron microscopy was applied to characterize GNPs doped Al2O3 feedstock, the surface morphologies of cemented carbide before and after spraying, and the wear track morphology of cemented carbide after wear tests. The phases of GNPs doped Al2O3 feedstock, uncoated and coated cemented carbide were analyzed by X‐ray diffraction. The existence of GNPs was analyzed by Raman spectroscopy. A mixture of un‐molten and molten splats formed on the surface of cemented carbide substrate after SHVOF thermal spray. The average coefficient of friction (CoF) of coated samples was slightly lower than that of uncoated samples, which might be due to the friction‐reduction effect of GNPs. The wear rate of the samples was one order of magnitude higher than that of the alumina ball, showing that the wear of samples was the main wear between the friction couples. The wear mechanism of uncoated sample was mainly fatigue spalling, and that of cemented carbide substrate coated with GNPs doped Al2O3 coating was mainly plowing and abrasive wear. [ABSTRACT FROM AUTHOR]

During the blending process, the choice of lubricant used in the internal mixer significantly affects the properties of composite materials. This study thoroughly investigates the mechanisms that enhance the mechanical properties and anti-wear characteristics of Natural Rubber/ Butadiene Rubber/Solution-Polymerized Styrene Butadiene Rubber composite materials by employing both commonly used lubricants and graphene-based lubricant mediums. The research offers data-driven insights to enhance material performance during internal mixer blending and protect the end-face metals. The incorporation of graphene as a lubricant additive results in its deposition on friction pair surfaces, forming a protective anti-wear layer that prevents direct contact between the friction pairs and effectively reduces wear. Throughout the blending process, the composite materials inevitably come into contact with the lubricant. This research reveals that the addition of lubricant improves the dispersion of SiO 2 particles while reducing aggregate formation. Consequently, the SiO 2 particles-TESPT-rubber crosslinking network becomes denser, significantly enhancing the performance of Natural Rubber/ Butadiene Rubber/Solution-Polymerized Styrene Butadiene Rubber composite materials. Specifically, when using commonly used lubricant mediums, the material's hardness, tensile strength, and tear strength increase by 0.88 %, 7.8 %, and 4.5 %, respectively. In contrast, under the graphene lubricant medium, these properties improve by 2.7 %, 16.8 %, and 24.9 %, respectively. Notably, Natural Rubber/ Butadiene Rubber/Solution-Polymerized Styrene Butadiene Rubber composite materials using the graphene lubricant medium experience substantial reductions in rolling resistance and improved anti-wet skid performance. When comparing Natural Rubber/ Butadiene Rubber/Solution-Polymerized Styrene Butadiene Rubber composite materials with and without lubricants, composites prepared with both commonly used lubricants and graphene lubricants show significant reductions in metal wear and changes in metal surface roughness. Metal wear decreases by 17.5 % and 28.7 %, respectively, while changes in metal surface roughness are reduced by 46.3 % and 68.7 %, respectively. • Choice of lubricant affects composite properties in blending. • Lubricants enhance SiO 2 dispersion, densifying networks, boosting properties. • Lubricants notably reduce metal wear, graphene ones most effective. [ABSTRACT FROM AUTHOR]

In this study, layered-structured Al 2 O 3 -based composites containing WC-Co, TiC, and MgO additives were prepared using hot-pressing sintering. The best comprehensive mechanical characteristics were acquired for the sample with a layer number (N LN) of 7 and thickness ratio (η TR) of 6. Its composite exhibited a fracture toughness of 8.5 and 8.4 MPa m1/2 in the X and Z directions, respectively. Analysis of the micro characteristics of the fracture surfaces of the Al 2 O 3 -TiC-WC-Co layered composites revealed a significant enhancement in the bending strength, which could be attributed to the mixed fracture modes in the composite, including intergranular and trans -granular modes. As the displacement increased, first, the bending stress of all the composites increased gradually, after which all the samples showed abrupt elevation in stress. The enhancement in the damage resistance of Al 2 O 3 -TiC-WC-Co layered composites could be attributed to the microscopic and macroscopic crack deflection, bridging, and partial surface bonding that occurred in the layers. Finally, a new theoretical perspective was employed to discuss the mechanism of the effect of the layered structure on the toughness of the composites. [ABSTRACT FROM AUTHOR]

The incorporation of graphene-based nanodispersoids in ceramic coatings is known to enhance the wear behavior of these materials. In this study, for the first time, alumina/graphene nanoplatelets (GNPs) coatings were deposited through Suspension High Velocity Oxy-Fuel (SHVOF) thermal spray on Al 2 O 3 /TiC substrate composites, which were laser microtextured with grid and line surface patterns. Dense coatings with around 8−10 μm thickness were obtained by spraying alumina suspension containing 1 wt. % GNPs. The tribological performance of the alumina/GNPs coatings on the Al 2 O 3 /TiC substrate composites was evaluated using ball-on-disc sliding wear tests. The alumina/GNPs coated Al 2 O 3 /TiC substrate composites textured with grid pattern showed the best tribological performance reaching a steady coefficient of friction (CoF) at lower sliding distances and presenting the lowest wear rate of the Al 2 O 3 /TiC substrate composites and the counterbody. [ABSTRACT FROM AUTHOR]

DCB (OA, DSB, SB)-MMT complexes were prepared by incorporating zwitterionic surfactants dodecyl dimethyl carboxylbetaine (DCB), N,N-dimethyldodecylamine N-oxide (OA), dodecyl dimethyl sulfobetaine (DSB) and 3-sulphonyl hexadecyldimethylamine (SB) into montmorillonite (MMT). The complexes were characterized by XRD, FT-IR, TGA/DTA and SEM, TEM. Results indicated that the interlayer distances of OA (DSB)-MMT depended on surfactant content and pH value, while those of DCB (SB)-MMT were only related to the surfactant content. The different thermal decomposition processes of complexes were closely related with pH values. Then the pesticide (lambda-cyhalothrin (LCT) or beta-cypermethrin (BCT)) - DCB(SB) micelles were incorporated into the galleries of LCT/DCB-MMT and BCT/SB-MMT hybrids. The basal spaces of LCT/DCB-MMT and BCT/SB-MMT were 4.03 and 4.64 nm, which were larger than those of DCB-MMT and SB-MMT, respectively. The pesticide intercalation was further confirmed by FTIR and TGA/DTA. Furthermore, the release behaviors of BCT (LCT) from the hybrids were compared and analyzed. The pesticide hybrids have the slow release property due to the strong interaction between DCB(SB) and MMT. The pseudo second-order and parabolic diffusion models can be well used to fit the release data. The present study is conducive to the application of MMT as good carriers of pesticide delivery system. [Display omitted] [ABSTRACT FROM AUTHOR]

In our present work, alumina/BNNTs and alumina/MoS 2 coatings were deposited onto stainless steel substrates by solution precursor high velocity oxy-fuel thermal spraying. The phase evolution, microstructure and tribological properties of the two kinds of coatings were studied. Investigation of the phased content showed that Al 2 O 3 , BN and MoS 2 survived in the coatings after being sprayed with SHVOF technology. Cross-section images of the coatings showed that the interface between the coating and the substrate was well bonded, and there were no obvious particle inclusions and defects at the interface. The top morphology of the coatings exhibited certain degree of particle deformation, which was conducive to the formation of a more compact coating with less porous and better bonding strength with the substrate. Dry sliding tests showed that alumina/BNNTs and alumina/MoS 2 coating improved the tribological properties of the samples and they were suitable for low load friction conditions (5 and 10 N). A crack evolution model was proposed to analyze the failure of coatings. This work could provide a reference for the application of the two coatings in the field of friction and wear. • Alumina/BNNTs and alumina/MoS 2 were deposited onto a stainless steel substrate using SHVOF thermal spraying. • The top morphology of the coatings exhibited a certain degree deformation of the particles. • The wear mechanisms of the coatings were dominated by coating peeling off, adhesion and abrasive wear. • A crack evolution model was proposed to analyze the failure of coatings. [ABSTRACT FROM AUTHOR]

The lifetime of ceramic tool is decreased because of the extension of cracks, and it will be prolonged if the cracks can be self healed. The healing ability of laminated Al 2 O 3 cutting tool composites (Al 2 O 3 -(WC-Co)-MgO/Al 2 O 3 –TiC–MgO) were assessed. For determining which laminated structure and the healing condition was the best for the composite, the flexural strength and recovery rates were measured and different healing condition were used. XRD, EDS and SEM technology were carried out to identify their compositions and microstructures after the healing. The number of cracks filled with TiO 2 , crack size and the oxide content effect were utilized to explain why the flexural strength and recovery rates of laminated Al 2 O 3 cutting tool composite after the healing were different. A single particle model was utilized to identify the relation between the threshold time, grain size and the self healing temperature of the composites. [ABSTRACT FROM AUTHOR]

The thermal shock resistance (TSR) of laminated Al 2 O 3 –TiN–MgO/Al 2 O 3 –ZrB 2 –MgO ceramic (LAMC) and Al 2 O 3 –TiN–MgO ceramic (ATMC) composites were investigated systematically by combining experimental data with stress intensity state theory. The microstructures and relative displacements before and after quenching, crack propagation, residual flexural strengths, and critical thermal shock temperature differences (Δ T c) of the LAMC and ATMC composites were identified and investigated. The TSR of the LAMC composite was higher than that of the ATMC composite as determined by comparing micro and macro features of LAMC and ATMC composites. The effects of different experimental approaches on the TSR of LAMC and ATMC composites were analysed. The analysed values of Δ T c for LAMC and ATMC composites, acquired based on stress intensity state theory, were consistent with the experimental data of crack propagation. [ABSTRACT FROM AUTHOR]

The laminated Al 2 O 3 –ZrB 2 –MgO/Al 2 O 3 –TiN–MgO (AZTM) ceramic composites were fabricated by hot-press sintering technology. The mechanical properties, microstructures and fracture behaviors of the laminated AZTM ceramic composites, were investigated comprehensively from the micro and macro scale perspectives. The residual stresses, R -curve behaviors and displacement in the laminated AZTM ceramic composites were calculated and analyzed. Compared to the monolithic Al 2 O 3 –TiN ceramic composite, the remarkable improvement in the fracture toughness of the laminated AZTM ceramic composite was obtained. Micro and macro crack deflection, crack bifurcation, bridging toughening and serrated propagation were helpful to the enhancement of the fracture toughness. An intracrystalline/intergranular mixed microstructure, as well as the combination of intergranular failure and transgranular failure contributed to the improvement of the flexural strength for the laminated AZTM ceramic composite. [ABSTRACT FROM AUTHOR]

The comprehensive effect of the mechanical properties, laminated structure and healing conditions on the self-healing behaviors of laminated Al 2 O 3 -MgO ceramic composites was researched. The flexural strengths before and after healing at the temperatures of 715, 815 and 915 °C for 30 min, 60 min and 90 min were measured. According to recovering rate the best healing condition was 900 °C for 60 min. The crack-healing ability of the laminated Al 2 O 3 -MgO ceramic composites was improved due to the enhancement of the original flexural residual effect and the oxide content effect by the elimination of pores and the filling of cracks. In addition, the factors influencing the original flexural residual effect and the oxide content effect were analyzed. Meanwhile, the effects of the particle size and the healing temperature on the healing ability were analyzed qualitatively based on the healing of a single particle model. [ABSTRACT FROM AUTHOR]

According to the tensile crack model, a simple model for tribological behaviors of diopside/AlTiB toughened alumina matrix ceramic guideway materials, predicting the relationship between load and wear rate, was presented. 45# steel ring was used as the counterpart. Mechanical properties and wear properties of the guideway materials under different loads were investigated. SEM micrographs of wear tracks on typical specimens were studied. Results showed that the experimental data described in this paper were in accordance with the theoretical prediction. Introduction of diopside and AlTiB master alloys in alumina matrix ceramic guideway materials improved their mechanical properties, friction and wear properties. The wear rate of pure alumina was in the order of 10 −15  m 3 /N·m while that of guideway materials toughened by diopside and AlTiB master alloys was in the order of 10 −16  m 3 /N·m. The wear mechanisms of pure alumina may be brittle fracture and grain pull-out. The dominant wear mechanisms of alumina matrix ceramic guideway materials toughened by diopside and AlTiB master alloys may be mechanical interlocking and plastic deformation combined with a little micro-fracture and grain pull-out. [ABSTRACT FROM AUTHOR]

Superparamagnetic Fe3O4hollow sub-microspheres (FHSM) with strong response to an external magnet were prepared via a solvothermal method, followed by acid etching. Lipase fromCandidasp. 99–125 was directly immobilized onto the amino-functional FHSM by simple adsorption, without glutaraldehyde linkage. The immobilized lipase was used to catalyze the esterification/transesterification of waste cooking oil with methanol to produce fatty acid methyl ester (FAME), a major source of biodiesel. FAME yield exceeded 93.4% over a wide range of temperatures from 10 to 40 °C. Notably, stability was clearly improved at the lower temperatures, in particular, giving a FAME yield of 89.6% after eight cycles of use at 10 °C. [ABSTRACT FROM PUBLISHER]

Grid and line textures were made on the top surfaces of WC-TiC-Co cemented carbide substrates. Suspension High Velocity Oxy-Fuel (SHVOF) was utilized to deposit alumina and graphene nanoplatelets (GNPs) coating on the textured surfaces. The friction and wear behaviors of the Alumina/GNPs coating were evaluated using dry sliding wear tests against alumina balls. The friction reduction mechanism of alumina/GNPs coating was presented. GNPs in the alumina coatings played a significant role in reducing the coefficient of friction (CoF) up to 40 % and improving the wear resistance properties of the coating. A stress distribution model of the friction contact zone was provided to analyze the tribological performance of the textured sample. The friction reduction mechanism for alumina/GNPs coating was discussed. These results offer a benchmark for further studies combining microtextured surfaces and SHVOF thermal sprayed coatings as promising candidates for high wear resistant applications. • The stress distribution model of the friction contact zone was provided. • A wear mechanism for GNPs doped Al 2 O 3 coatings was proposed. • A thin, controlled layer which preserved the texture surface morphology was formed. [ABSTRACT FROM AUTHOR]

Grid and line textures were made on the top surfaces of WC-TiC-Co cemented carbide substrates. Suspension High Velocity Oxy-Fuel (SHVOF) was utilized to deposit alumina and graphene nanoplatelets (GNPs) coating on the textured surfaces. The friction and wear behaviors of the Alumina/GNPs coating were evaluated using dry sliding wear tests against alumina balls. The friction reduction mechanism of alumina/GNPs coating was presented. GNPs in the alumina coatings played a significant role in reducing the coefficient of friction (CoF) up to 40 % and improving the wear resistance properties of the coating. A stress distribution model of the friction contact zone was provided to analyze the tribological performance of the textured sample. The friction reduction mechanism for alumina/GNPs coating was discussed. These results offer a benchmark for further studies combining microtextured surfaces and SHVOF thermal sprayed coatings as promising candidates for high wear resistant applications. • The stress distribution model of the friction contact zone was provided. • A wear mechanism for GNPs doped Al 2 O 3 coatings was proposed. • A thin, controlled layer which preserved the texture surface morphology was formed. [ABSTRACT FROM AUTHOR]

The aim of present study is to develop an efficient and low-cost method for capsaicin production isolated from capsaicinoids by macroporous resin adsorption chromatography. HZ816 resin has shown the best adsorption and desorption capacities for capsaicin among other resins. To optimize the operating parameters for separation, initial concentration, diameter-to-height ratio, mobile phase ratio, and crystallization method were investigated. When capsaicinoids solution (5 g/L) was loaded onto the column (diameter-to-height ratio = 1:12) with ethanol/1% w/w NaOH (4:6, v/v) as the mobile phase, capsaicin was purified most effectively. By using acid neutralization as the crystallization method, the purity of capsaicin improved from 90.3 to 99.5% with 82.3% yield. In conclusion, this study provides a simple and low-cost method for the industrial-scale production of high-purity capsaicin. [ABSTRACT FROM AUTHOR]

The rapid nucleic acid extraction is essential, particularly the communicable diseases pandemic. In this work, aluminum modified Fe3O4 (Fe3O4@Al3+) particles were successfully synthesized by solvthermal method, epoxidation, covalent binding of iminodiacetic acid and Al3+ ions coordination for DNA extraction. Fe3O4@Al3+ particles could greatly improve the efficiency of DNA extraction and the extraction could be totally completed within 15 minutes at the optimum condition. The simple and rapid method is mainly based on the Fe3O4@Al3+ particles, which have large specific surface area, superparamagnetism, and Al3+ ions affinity to DNA. Additionally, several characterizations were carried out to further investigate the features of Fe3O4@Al3+ particles. According to SEM image, the average dimension of monodispersed Fe3O4@Al3+ spheres was around 200 nm. XPS results showed the existence of Al3+ on the surface of Fe3O4 particles, which further demonstrated the success of metal chelation in this material synthesis. The XRD patterns indicated that the Fe3O4@Al3+ particles were the inverse spinel structure as the bare Fe3O4 particles. Good magnetism of Fe3O4@Al3+ particles determined by VSM indicated that this material could be easily separated from the reaction system. To summarize, Fe3O4@Al3+ particles is expected to play an important role in future DNA extraction due to remarkable performance. The DNA separation media Fe3O4@Al3+ particles were successfully synthesized. DNA adsorption was effectively achieved by Fe3O4@Al3+ particles based on metal chelation. DNA extraction was significantly boosted by Fe3O4@Al3+ particles. [ABSTRACT FROM AUTHOR]

Highlights: [•] A facile one-pot hydrothermal method to synthesize ZnS(MAA) QDs. [•] Synthesis and in situ modification of ZnS(MAA) QDs in a single process. [•] Controllable ZnS(MAA) QD size in the range 4–10nm by varying the reaction time. [•] Excellent dispersibility of ZnS(MAA) QDs in water. [•] 50% of the fluorescence signal intensity retained after storage for 6months. [Copyright &y& Elsevier]

Abstract: In the present work, diopside and AlTiB were simultaneously introduced in alumina using pressureless sintering. Microstructures of the composites were observed at a given temperature of 1520°C and different holding time. Sintering densification process of the composites was studied. Experiments were performed in the temperature at equal increments: 1420, 1520, 1620 and 1720°C, and with four holding times, i.e. 100, 140, 180 and 220min. The apparent activation energies of 17.7–28.8kJ/mol for alumina matrix ceramic materials were calculated by least squares. The sintering kinetic equations were deduced. Results showed that the sintering of monolithic alumina was controlled by volume diffusion, and that of alumina matrix ceramic materials doped with diopside and AlTiB was controlled by grain boundary diffusion and volume diffusion. [Copyright &y& Elsevier]

Abstract: In this work, diopside was introduced in hydroxyapatite matrix as a sintering aid and hydroxyapatite/diopside ceramic composites were fabricated by uniaxial hot-pressing. The biological activity of hydroxyapatite/diopside ceramic composites in simulated body fluid was assessed by means of scanning electron microscopy (SEM), thin-film X-ray diffraction (TF-XRD) and electron-probe micro analysis (EPMA). SEM micrographs showed an obvious bright mineral layer to form on the soaked composite surface, and the layer may be hydroxyapatite or NaCl crystals. [Copyright &y& Elsevier]

Abstract: Al2O3/diopside ceramic composites with good mechanical properties were prepared by uniaxial hot-pressing and their biological activity in simulated body fluid was studied by SEM, XRD, FT-IR and EPMA. SEM micrographs showed a lath-like apatite layer to form on the soaked composite surface, whose good biological activity may be of some promise for biomedical application. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, TiO2 was introduced into boron carbide and B4C-based ceramic composites were obtained by uniaxial hot pressing. The mechanical properties, relative density and erosion behaviour of B4C-based ceramic composites were investigated. X-ray analysis showed that the fabricated composites were composed of B4C, TiB2 and C phases. SEM technique was employed to observe the original polished surfaces and the eroded surfaces of B4C-based ceramic composites. The effect of impingement angle, impact velocity of SiC erodent particle, relative density and phase ratio on the erosion rate of B4C-based ceramic composites was determined. It was found that the erosion rate of B4C-based ceramic composites increased with increasing of impingement angle and erodent particle velocity. The relative density and phase ratio influenced the erosion rate of B4C-based ceramic composites significantly by influencing their mechanical properties. [Copyright &y& Elsevier]

Abstract: B4C matrix ceramic composites toughened by Al2O3 and TiC were prepared by low pressure hot pressing. The relative density, Vickers hardness, fracture toughness and flexural strength of the new fabricated composites were measured. Microstructure observations of the fracture surfaces and the indentation cracks of the B4C matrix ceramic composites were analyzed, and an X-ray diffraction phase analysis was performed. The experiment results showed that chemical reactions took place during the low pressure hot pressing process and resulted in the B4C/Al2O3/TiB2 composite. The densification rate of the B4C matrix ceramic composites was enhanced and the mechanical properties were improved via the introduction of Al2O3 and TiC additives. The Vickers hardness, fracture toughness and flexural strength of the composite with the addition of 4.7wt.% Al2O3 and 10wt.% TiC were 24.8GPa, 4.8MPam1/2 and 445MPa, respectively. [Copyright &y& Elsevier]

Abstract: B4C matrix ceramics with different content of Al and TiO2 were fabricated by hot-press sintering, and sinterability of B4C matrix ceramics was investigated by addition of TiO2 and Al. X-ray diffraction analysis showed that in situ reaction between B4C and TiO2 happened, and TiB2 was formed during sintering. Vickers hardness, fracture toughness and flexural strength of the fabricated composites were measured. Results showed that the densification rate and mechanical properties of B4C matrix ceramics were significantly improved due to the introduction of TiO2 and Al. The eliminating of B2O3 (impurity in B4C) and the interface reaction contributed to the densification rate. The enhanced flexural strength was obtained owing to change of fracture mode and the improvement in fracture toughness was due to the formation of microcracks and deflection of propagating cracks caused by the thermal expansion mismatch between TiB2 and B4C matrix. [Copyright &y& Elsevier]

Abstract: Al–Ti–B master alloys and diopside are simultaneously introduced in alumina matrix ceramic materials as sintering aids. Fine structural alumina matrix ceramic materials are fabricated by pressureless sintering during which liquid phase, leading to interface reactions between alumina matrix and additives, is formed. Hardness, fracture toughness and bending strength of the composites are measured. The effects of diopside on mechanical properties and fracture mechanism of fine structural alumina matrix ceramic materials are analyzed together with the microstructure observations on fracture surfaces, the polished surfaces and the indentation cracks. [Copyright &y& Elsevier]

Abstract: Al–Ti–B master alloys and diopside were incorporated into alumina matrix and advanced alumina matrix ceramic materials were fabricated by pressureless sintering technology. The mechanical properties of this new composite as well as its wear behaviours, coupled with carbon steel ring in unlubricated conditions at room temperature, were investigated systemically. SEM technology was adopted to observe the worn surfaces of specimens and wear mechanisms were simultaneously discussed. Analysis of the experimental data and observations on the worn surfaces revealed that the improvement in the wear resistance of the composites might be attributed mainly to the strong toughening effect due to the introduction of Al–Ti–B master alloys and diopside in the alumina matrix. [Copyright &y& Elsevier]

Abstract: Diopside and Fe2O3 were introduced in alumina matrix ceramic materials. Large-scale fine structural alumina matrix ceramic guideway materials were fabricated by the technology of pressureless sintering, during which liquid phase sintering took place and new phases such as 3Al2O3·2SiO2, CaO·Al2O3·2SiO2 and CaO·6Al2O3 were produced by the chemical reactions taking place among alumina and the additives. The hardness, the fracture toughness and the bending strength of the guideway products were tested. The influences of diopside and Fe2O3 additions were studied by microstructural observations and mechanical properties evaluations. Meanwhile, the expected improvement of mechanical properties compared with pure alumina was indeed observed. The fracture mechanism and porosity of large-scale fine structural alumina matrix ceramic guideway materials were analyzed. [Copyright &y& Elsevier]

Abstract: In this paper, diopside was introduced into alumina as a sintering aid and fine structural alumina matrix ceramic materials were fabricated by the technology of pressureless sintering. The relative density, hardness and fracture toughness of the diopside-reinforced composites were investigated. Tribological tests were carried out at a rotation speed ranged from 40 to 160rpm and in a normal load ranged from 50 to 200N. SEM technique was employed to observe worn surfaces of the test specimens and wear mechanisms were simultaneously discussed. Analysis of the experimental data and observations on worn surfaces revealed that the improvement in wear resistance of composites may be attributed mainly to the stronger toughening effect due to addition of diopside in alumina matrix. [Copyright &y& Elsevier]

Abstract: In the present work, a new technique to improve the performances of alumina matrix ceramic materials is presented, in which Al, Al3Ti and TiB2 are incorporated into alumina matrix ceramic materials in the form of Al–Ti–B master alloys. Composites of Al2O3/TiB2/AlN/TiN are fabricated by the technology of transient liquid phase sintering, during which new phases such as AlN and TiN are produced by the chemical reactions taking place among Al, Ti and N2 (the protective atmosphere). The densification rate of the composites as a function of Al–Ti–B volume content is discussed. The fundamental properties of the composites such as hardness, fracture toughness and bending strength are examined. The relations of volume content of Al–Ti–B master alloys and mechanical properties of alumina matrix ceramic materials are analyzed. The effects of fracture mechanism on mechanical properties of the composites are researched together with the refining performances of Al–Ti–B master alloys. [Copyright &y& Elsevier]

Abstract: In the present work, Al–Ti–C master alloys and diopside are introduced in alumina matrix ceramic materials. Composites are fabricated by the technology of transient liquid phase sintering, during which new phases such as Al6Si2O13, AlN and CaO·6Al2O3 are produced by the chemical reactions taking place among alumina and the additives. The densification rate of the composites as a function of Al–Ti–C volume content is discussed. The hardness, the fracture toughness and the bending strength of the composites are tested. Meanwhile, the effects of additives on mechanical properties and fracture mechanism of alumina matrix ceramic materials are analyzed and discussed together with the refining performances of Al–Ti–C master alloys. [Copyright &y& Elsevier]

Abstract: A new technique to toughen alumina matrix ceramics is presented, in which Al and TiC are incorporated into the matrix ceramic in the form of Al–Ti–C master alloys, meanwhile ZrO2 are introduced to Al2O3/Al–Ti–C composites. Composites of Al2O3/TiC/ZrO2/AlN and Al2O3/TiC/AlN were fabricated by the technology of transient liquid phase sintering, during which new AlN phase was produced by the chemical reactions taking place between Al and N2 (the protection atmosphere). The toughening effect of Al–Ti–C master alloys on alumina matrix ceramics was researched along with the influence of combination of Al–Ti–C master alloys and ZrO2. Mechanical properties of the composites were determined and the microstructures were analyzed. [Copyright &y& Elsevier]

• Chirality transformation and amplification was realized in chitosan hydrogel. • The multiple chiroptical switches were fabricated basing on the external stimuli. • Chiral logic gates and logic circuit were successfully designed. A chitosan-based chiral hydrogel was fabricated by grafting achiral salicylaldehyde (SA) on chitosan chains, followed by supramolecular assembly (CS-SA hydrogel hereafter). The structures and properties of the CS-SA hydrogel were characterized and investigated. The results indicated that the swelling ability of the CS-SA hydrogel depended on the medium pH and crosslinking degree. Circular dichroism measurements revealed that the chiral information of the chitosan was successfully transcribed to the achiral salicylic chromophores through imine bonds. Chiroptical switches based on acid-base responses of the imine bond and the OH fragment of SA and the swelling properties of the CS-SA hydrogel were fabricated, which is first reported for a chitosan-based hydrogel. In addition, a gel film showed good fatigue resistance under external stimuli. IMPLICATION, INHIBIT, and PASS logic gates and a logic circuit based on the chiroptical switches were successfully designed. This study suggests a new method of constructing biobased chiral functional materials. [ABSTRACT FROM AUTHOR]

Background: As the most common subtype of adult muscular dystrophy worldwide, large cohort reports on myotonic dystrophy type I (DM1) in China are still lacking. This study aims to analyze the genetic and clinical characteristics of Chinese Han DM1 patients. Methods: Based on the multicenter collaborating effort of the Pan-Yangtze River Delta Alliance for Neuromuscular Disorders, patients with suspected clinical diagnoses of DM1 were genetically confirmed from January 2020 to April 2023. Peak CTG repeats in the DMPK gene were analyzed using triplet repeat-primed PCR (TP-PCR) and flanking PCR. Time-to-event analysis of onset age in females and males was performed. Additionally, detailed clinical features and longitudinal changes from the disease onset in 64 DM1 patients were retrospectively collected and analyzed. The Epworth Sleepiness Scale and Fatigue Severity Scale were used to quantify the severity of daytime sleepiness and fatigue. Results: Among the 211 genetically confirmed DM1 patients, the mean age at diagnosis was 40.9 ± 12.2 (range: 12–74) with a male-to-female ratio of 124:87. The average size of CTG repeats was 511.3 (range: 92–1945). Among the DM1 patients with comprehensive clinical data (n = 64, mean age 41.0 ± 12.0), the age at onset was significantly earlier in males than in females (4.8 years earlier, p = 0.026). Muscle weakness (92.2%), myotonia (85.9%), and fatigue (73.4%) were the most prevalent clinical features. The predominant involved muscles at onset are hands (weakness or myotonia) (52.6%) and legs (walking disability) (42.1%). Of them, 70.3% of patients had daytime sleepiness, 14.1% had cataract surgery, 7.8% used wheelchairs, 4.7% required ventilatory support, and 1.6% required gastric tubes. Regarding the comorbidities, 4.7% of patients had tumors, 17.2% had diabetes, 23.4% had dyspnea, 28.1% had intermittent insomnia, 43.8% experienced dysphagia, and 25% exhibited cognitive impairment. Chinese patients exhibited smaller size of CTG repeats (468 ± 139) than those reported in Italy (613 ± 623), the US (629 ± 386), and Japan (625 [302, 1047]), and milder phenotypes with less multisystem involvement. Conclusion: The Chinese Han DM1 patients presented milder phenotypes compared to their Caucasian and Japanese counterparts. A male predominance and an early age of onset were identified in male Chinese Han DM1 patients. [ABSTRACT FROM AUTHOR]

A non-enzymatic acetylcholine (ACh) electrochemical biosensor was constructed based on flower-like NiAl layered double hydroxides (NiAl-LDHs) decorated with carbon dots (CDs). The flower-like NiAl-LDHs with a cross-linking nanosheet structure and high specific surface area were hydrothermally fabricated. Then CDs with negative surface charge were decorated on the NiAl-LDHs with positively charged brucite-like layers to obtain NiAl-LDH/CD composites. Compared with the NiAl-LDHs, the NiAl-LDH/CD composites exhibited enhanced electroconductivity and electrocatalytic performance for ACh oxidation. The NiAl-LDH/CD composites modified glassy carbon electrode had a wide linear response range of 5–6885 μM, high sensitivity of 133.20 ± 0.03 mA M −1 cm −2 and low limit of detection of 1.7 μM, which are superior among the non-enzymatic ACh electrochemical biosensors. The biosensor also exhibited a good durability and long-term stability, and an excellent selectivity for ACh detection. The good performance in the non-enzymatic detection of ACh could be attributed to the synergistic effect between NiAl-LDHs and CDs. [ABSTRACT FROM AUTHOR]

α-Arbutin is a glycosylated hydroquinone that has an inhibitory function against tyrosinase. The aim of the present study is to develop an efficient and inexpensive method for large-scale production of α-arbutin by using Xanthomonas BT-112 as biocatalyst. To accomplish this goal, various surfactants were tested to enhance the α-arbutin production, and the optimal operational conditions for 30 L jar fermenter were scaled up for a production level of 3000 L with using a constant volumetric oxygen transfer coefficient ( K L a ) and the volumetric aeration rate per volume unit ( Q / V ) as scale-up criteria. Under the optimized conditions, the α-arbutin produced in the presence of 0.4% (w/v) Tween-80 was 124.8% higher than that of the control, and the yield of α-arbutin in 3000 L fermenter was 38.2 g/L with a molar conversion ratio of 93.7% based on the amount of hydroquinone supplied. This result is comparable to the results from laboratory-scale fermenter. Hence, 100-fold scale-up was successfully achieved. [ABSTRACT FROM AUTHOR]

Background: The ratio of triglycerides (TG) to high-density lipoprotein cholesterol (HDL-C) bears a relation with poor outcomes of acute ischemic stroke (AIS), but the impact of serum TG/HDL-C level on post-stroke cognitive impairment (PSCI) remains unknown. We conducted this prospective study to explore the association between TG/HDL-C and PSCI.Methods: Consecutive AIS patients from the Stroke Units of our hospital were prospectively enrolled between July 1, 2020, and June 30, 2021. Blood samples were collected within 24 h after admission. Cognition function was evaluated by the Montreal Cognitive Assessment (MoCA) at 3 months after stroke. We used logistic regression analyses to explore the relationship between TG/HDL-C and PSCI, and then used a receiver operating characteristic (ROC) analysis to assess the ability of acute TG/HDL-C for predicting PSCI.Results: A total of 227 AIS patients were recruited. Compared with patients without PSCI, those with PSCI had a higher level of TG/HDL-C at admission (P < 0.01). The multivariate logistic regression analyses showed that TG/HDL-C level was independently associated with PSCI (P < 0.01). The area under the curve of the ROC for TG/HDL-C as predictor of PSCI was 0.701 (95%CI 0.635-0.768). The optimal cutoff value of TG/HDL-C to indicate PSCI was 1.564, which gave a sensitivity of 55.2% and specificity of 80.6%.Conclusions: Our study demonstrated that a higher level of TG/HDL-C at the acute phase of ischemic stroke predicted the presence of PSCI at 3 months after stroke. [ABSTRACT FROM AUTHOR]

Superparamagnetic Fe 3 O 4 sub-microspheres with diameters of approximately 200 nm were prepared via a solvothermal method, and then modified with epoxychloropropane. Lipase was immobilized on the modified sub-microspheres. The immobilized lipase was used in the production of biodiesel fatty acid methyl esters (FAMEs) from acidified waste cooking oil (AWCO). The effects of the reaction conditions on the biodiesel yield were investigated using a combination of response surface methodology and three-level/three-factor Box–Behnken design (BBD). The optimum synthetic conditions, which were identified using Ridge max analysis, were as follows: immobilized lipase:AWCO mass ratio 0.02:1, fatty acid:methanol molar ratio 1:1.10, hexane:AWCO ratio 1.33:1 (mL/g), and temperature 40 °C. A 97.11% yield was obtained under these conditions. The BBD and experimental data showed that the immobilized lipase could generate biodiesel over a wide temperature range, from 0 to 40 °C. Consistently high FAME yields, in excess of 80%, were obtained when the immobilized lipase was reused in six replicate trials at 10 and 20 °C. [ABSTRACT FROM AUTHOR]

Nano-alumina/hydroxyapatite composite powders for biomedical applications were synthesized by in-situ chemical precipitation. The effects of synthesis parameters and calcination on the properties of the composite powders were studied. The morphology, chemical composition and thermal behavior of the composite powders were investigated by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The results showed that crystallinity of the composite powders progressively increased with increasing the synthesis and calcination temperatures. During calcination, the hydroxyapatite was transformed into calcium phosphate (β-TCP) at 1100 °C, while the aluminum hydroxide was converted to γ-alumina and θ -alumina. In addition, aggregations were observed for samples heated at 1000 °C and above. The as-synthesis alumina powders with an average particle size of approximately 30 nm were well distributed around the HA particles. [ABSTRACT FROM AUTHOR]

Rebaudioside D (RD) is a natural low-calorie, high-sweet sweetener and an excellent sugar substitute. In this study, RD was produced by coupling glucosyltransferase (EUGT11) and sucrose synthase (SUS) with a novel strategy of immobilization to enhance the recyclability of enzymes and decrease the production costs of RD. Recombinant EUGT11 from Oryza sativa and SUS from Arabidopsis thaliana were expressed in Escherichia coli and immobilized onto Fe 3 O 4 @Uio-66 nanocomposite. The results of Fourier transform Infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), magnetic susceptibility (VSM), thermogravimetric (TG) analysis and Brunauer–Emmett–Teller (BET) indicated that the magnetic nanocomposite Fe 3 O 4 @Uio-66 was successfully fabricated and the two enzymes were separately immobilized on Fe 3 O 4 @Uio-66. The reusability, storage, pH and temperature stabilities of the immobilized enzymes were investigated and compared to that of free enzymes. It was more stable towards temperature compared with free enzyme. The kinetic properties of immobilized EUGT11 showed a lower V m and a higher K m compared to free EUGT11, and immobilized SUS showed a lower V m and K m compared to free SUS. The immobilized SUS had around 56% residual activity upon storage a period of 10 days at 4 °C. After 8 times, the catalytic activity of immobilized double enzyme still retained around 80%, which showed a desirable stability and reduced the overall cost of enzymes, indicating that the immobilized enzymes had a good industrial application prospect in RD production. [Display omitted] • Double-enzyme biocatalyst of glucosyltransferase and sucrose synthase was prepared. • Glucosyltransferase and sucrose synthase were first immobilized on Fe 3 O 4 @Uio-66. • The thermostability of enzyme was improved by immobilization. • The activity of immobilized double enzyme was maintained at 80% after 8 times of recycling. [ABSTRACT FROM AUTHOR]

Effective quench detection technologies are extremely important for protecting high temperature superconducting (HTS) applications. In recent years, an optical fiber encapsulated HTS tape (OF-tape) is proposed for quench detection by using distributed temperature sensing (DTS) technology. In this paper, an HTS coil (OF-coil) wound with a 39 m long OF-tape was prepared and energized by an AC overcurrent of 700 A to verify the feasibility of temperature observation during quench events. Furthermore, anti-stokes intensity was also measured to understand dependence of temporal resolutions on response times of coil quenches. The main results show that temperature variations of the OF-coil can be correctly measured after quench and the maximum temperature is shown at the middle turn of the OF-coil. Particularly, for the method of detecting anti-stokes intensity, quench response time of temporal resolution (TR.) with 30 ms is about 500 ms faster than that with 300 ms. However, when the TR. is 30 ms, more noise signal is observed. Accordingly, a trade-off should be considered between response time and noise signal for efficient quench detection. [ABSTRACT FROM AUTHOR]

The TiB 2 -TiC-Al 2 O 3 multi-dimensional gradient ceramic tool (MDGCT), whose composition varied in two directions, were designed and fabricated via hot-pressed vacuum sintering. The cutting performance, including cutting force, cutting temperature and chip morphology, and failure mechanisms of MDGCT with different orientation angles in intermittent turning of SKD11 hardened steel were investigated in comparison with the homogeneous commercial ceramic tool CC650 at different depths of cut and cutting speeds. And the distribution of thermal residual stress of MDGCT was investigated employing FEM analysis. Results showed that the multi-dimensional gradient ceramic tool with orientation angle of 15 degree (TT3A15) had the optimal comprehensive cutting performance. The main failure mechanisms of CC650 tool were chipping and fracture caused by crack propagation, while the crack propagation was effectively inhibited in the TT3A15 tool, and its failure mechanism was chipping at the tool nose. The contribution of multi-dimensional gradient structure of TT3A15 tool to the increasing residual compressive stress of minor cutting edge, the favorable anti-crack capacity of flank face and the heterogeneity of physical and mechanical properties of rake face were responsible for its optimal cutting performance. • The multi-dimensional gradient ceramic tool (MDGCT) were fabricated via hot-pressed vacuum sintering and employed in intermittent turning of SKD11 hardened steel. Results indicated that the cutting force, cutting temperature and chip morphology of TT3A15 are better than those of other cutting tools. • FEM analysis of MDGCT showed that the residual compressive stress increasing along minor cutting edge of MDGCT could effectively inhibit the propagation of crack. • The multi-dimensional gradient structure had a positive impact on its cutting performance. Firstly, the thermal conductivity of rake face increasing along major cutting edge is conductive to rapid conduction of cutting heat. Secondly, the facture roughness of MDGCT gradually increases in the direction of crack propagation at flank face, contributing to inhibiting crack propagation. [ABSTRACT FROM AUTHOR]

• Our study showed that the PD-PIGD and TD types have different basal ganglia iron deposition patterns. • The damaged putamen might be the pathophysiological basis of PD gait and posture disorders. • Iron deposition appears to differ between PD motor subtypes on different major motor symptom sides. The quantitative susceptibility mapping (QSM) technique was used to analyze the distribution pattern of iron deposition in the basal ganglia region of patients with motor subtypes of Parkinson's disease (PD) and to explore the difference in iron content in the basal ganglia region of PD motor subtypes on the major motor symptomatic side. The study included 76 patients with PD and 37 healthy controls (HC). Patients with PD were divided into two groups: postural instability/gait disorder (PIGD)(n = 48), and tremor dominance (TD)(n = 28). We classified patients with PD according to the side of the major motor symptoms as left PIGD (n = 23), left TD (n = 14), right PIGD (n = 25), and right TD (n = 14). All subjects underwent brain magnetic resonance scanning to obtain QSM and susceptibility values in the corresponding regions of interest (ROI). (1) Compared with the HC, the bilateral SN in the PD-PIGD and TD group showed greater susceptibility values. The susceptibility values in the left CN, bilateral PUT were also greater in the PD-PIGD group than the HC. (2) Compared with the TD, the left PUT susceptibility values were greater in the PIGD group, especially in patients whose major symptomatic side were on the right limb. (3) Correlation analysis showed that in the PD group, bilateral SN was positively correlated with the unified Parkinson's disease rating scale III part scores of the Movement Disorder Society (MDS-UPDRS III) and the Hoehn-Yahr stage. Bilateral dentate nucleus (DN) susceptibility values were significantly positively correlated with TD scores, and left PUT susceptibility values were positively correlated with PIGD scores. The left SN within the PIGD group was positively correlated with the PIGD score. There were different iron deposition patterns in the basal ganglia between the PD-PIGD and TD groups. There also seems to be a difference in iron deposition in PD motor subtypes on different major motor symptom sides. [ABSTRACT FROM AUTHOR]

In this study, high density NiAl/WC composite was successfully fabricated by a novel in-situ synthesis thermal explosion reaction method using Ni, Al and WC commercial powders as starting materials. In-situ synthesis of NiAl/WC composites requires the thermal explosion(TE) reaction to be ignited and fully controlled to maintain the geometry of the compressed parts. The temperature profiles were measured to monitor the reaction process. The results show that increasing WC content can increase the ignition temperature and decrease the maximum temperature in the synthesis process. Single phase NiAl can be produced by this new process regardless of the addition of WC. Microhardness of the products were tested to evaluate the performance of the synthesized composites. This work offers a low cost approach to NiAl/WC composites due to the very low synthesis temperature and extremely short processing time. [ABSTRACT FROM AUTHOR]

Carbon quantum dots (CQDs) with multiple surface states were prepared by high-energy ball milling a mixture of activated carbon and KOH, followed by ultrafiltration purification. The as-prepared CQDs exhibit dual-wavelength photoluminescence emission peaks. Most interestingly, the first emission peak is independent of excitation wavelength ( λ ex ) and the second one is dependent on λ ex and red shifts monotonically with increasing λ ex . Meanwhile, the as-prepared CQDs also present dual-wavelength electrochemiluminescence property. [ABSTRACT FROM AUTHOR]