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Environmental protection and social obligation fulfillment have become hot subjects as the "dual carbon" approach has been developed and deepened. The ESG system is consistent with China's current policies, abandoning the traditional business philosophy of economic supremacy in favor of comprehensively measuring corporate social responsibility and sustainable development capability across three dimensions: environmental (E), social (S), and corporate governance (G), which receive widespread attention from all sectors of society. Based on observational data from A-share listed businesses in Shanghai and Shenzhen from 2011 to 2020, this study empirically evaluates the influence and mechanism of ESG on government subsidies. The research results indicate that enterprises can receive more government subsidies by improving ESG performance. Mechanism analysis found that corporate transparency plays a positive mediating role in the process of ESG affecting government subsidies. Further research on political affiliation and property rights has found that companies without political affiliation are more inclined to receive more government subsidies by improving ESG performance, and the impact of political affiliation and ESG performance on government subsidies is mutually complementary. Enterprises with different property rights have different strengths of motivation to increase government subsidies by improving ESG performance. State owned enterprises (excluding central enterprises) are the strongest, followed by non-state-owned enterprises, and central enterprises are the weakest. Therefore, enterprises should be further encouraged to strengthen ESG construction, improve the quality of ESG information disclosure, improve resource allocation efficiency, and promote high-quality development of enterprises. [ABSTRACT FROM AUTHOR]

Ternary PtZrNi NRs have excellent electrocatalytic activity in cathode and cathode reactions of fuel cells. [Display omitted] Pt-based alloys with precise structure and composition design have been considered to be effective and robust novel electrocatalysts for fuel cells. Whereas, the sluggish kinetics of oxygen reduction reaction (ORR) and low intrinsic activity of Pt limited their real application on a large scale. Herein, a novel ternary PtZrNi nanorods (PtZrNi NRs) was synthesized via a facile wet-chemical method to achieve high electrocatalytic performance for both ORR and alcohol oxidation reaction owing to the synergism of chosen three elements and prominent one-dimensional morphology. Specifically, the PtZrNi NRs show enhanced mass and specific activities of 0.755 A mg Pt -1 and of 0.97 mA/cm2 at 0.9 V RHE towards ORR in acidic media, which are 4.7 and 4.4 times of those of commercial Pt/C, respectively. Additionally, in alkaline media, the PtZrNi NRs also exhibit superior ORR mass and specific activities of 3.216 A mg Pt -1and 4.13 mA/cm2, enhanced by 34.6 and 31.3 times compared with those of commercial Pt/C, respectively. The PtZrNi NRs retain the nanorod shape well without agglomeration after an accelerated durability test (20000 cycles). This work may offer a new perspective for engineering high-performance Pt-based electrocatalysts for commercial fuel cells. [ABSTRACT FROM AUTHOR]

Iron–nitrogen-doped carbon (Fe–N–C) catalysts have been theoretically and experimentally demonstrated as one of the most promising materials to promote the oxygen reduction reaction (ORR), but they still have drawbacks in terms of stability and longevity. Herein, a novel strategy of loading Fe–N–C on cerium oxide cyanamide (Ce2O2CN2) is proposed to increase the density of active sites and improve the activity effectively. Ce2O2CN2 provides a Ce4+/Ce3+ redox pair to regulate the oxygen density on the catalyst surface, and the π–π interactions between Ce2O2CN2 and Fe–N–C are beneficial for interfacial charge transport. Consequently, Fe–N–C@Ce2O2CN2 shows excellent ORR activity with a half-wave potential (E1/2) of 0.89 V vs RHE and satisfactory long-term durability in an alkaline medium, and significantly outperforms commercial Pt/C. The Zn–air batteries made using the prepared catalyst exhibited a high peak power density of 119.35 mW cm−2. This study provides a new perspective for the application of platinum group-metal (PGM)-free catalysts in next-generation energy storage devices. [ABSTRACT FROM AUTHOR]

Mycobacterium neoaurum DSM 1381 originated from Mycobacterium neoaurum ATCC 25790 by mutagenesis screening is a strain of degrading phytosterols and accumulating important C22 steroid intermediates, including 22-hydroxy-23, 24-bisnorchola-4-en-3-one (4-HP) and 22-hydroxy-23, 24-bisnorchola-1,4-dien-3-one (HPD). However, the metabolic mechanism of these C22 products in M. neoaurum DSM 1381 remains unknown. Therefore, the whole-genome sequencing and comparative genomics analysis of M. neoaurum DSM 1381 and its parent strain M. neoaurum ATCC 25790 were performed to figure out the mechanism. As a result, 28 nonsynonymous single nucleotide variants (SNVs), 17 coding region Indels, and eight non-coding region Indels were found between the genomes of the two strains. When the wild-type 3-ketosteroid-9α-hydroxylase subunit A1 (KshA1) and β-hydroxyacyl-CoA dehydrogenase (Hsd4A) were overexpressed in M. neoaurum DSM 1381, the steroids were transformed into the 4-androstene-3, 17- dione (AD) and 1,4-androstadiene-3,17-dione (ADD) instead of C22 intermediates. This result indicated that 173N of KshA1 and 171K of Hsd4A are indispensable to maintaining their activity, respectively. Amino acid sequence alignment analysis show that both N173D in KshA1 and K171E in Hsd4A are conservative sites. The 3D models of these two enzymes were predicted by SWISS-MODEL and AlphaFold2 to understand the inactivation of the two key enzymes. These results indicate that K171E in Hsd4A may destroy the inaction between the NAD+ with the NH3+ and N173D in KshA1 and may disrupt the binding of the catalytic domain to the substrate. A C22 steroid intermediates–accumulating mechanism in M. neoaurum DSM 1381 is proposed, in which the K171E in Hsd4A leads to the enzyme's inactivation, which intercepts the C19 sub-pathways and accelerates the C22 sub-pathways, and the N173D in KshA1 leads to the enzyme's inactivation, which blocks the degradation of C22 intermediates. In conclusion, this study explained the reasons for the accumulation of C22 intermediates in M. neoaurum DSM 1381 by exploring the inactivation mechanism of the two key enzymes. [ABSTRACT FROM AUTHOR]

The high performance Si 3 N 4 ceramic was prepared firstly for TiO 2 , Y 2 O 3 and MgO as pressureless sintering additives. Si 3 N 4 ceramic with relative density of 99.6% and flexural strength of 785 ± 23.3 MPa could be obtained with 3 mol% TiO 2 and sintered at 1800 °C for 2 h. After annealing at 1700 °C, the facture toughness of sample of 1 mol% TiO 2 increased from 8.31 ± 0.28 MPa m1/2 to 9.84 ± 0.16 MPa m1/2. The flexural strength of sample of 2 mol% TiO 2 increased from 707 ± 26 MPa to 981 ± 16 MPa, thermal conductivity increased from 57.8 W/(m·K) to 68.49 W/(m·K). The XRD results showed that the ratio of I 101 / I 210 and grain height reached to 1.84 and 5 μm of the sample of 3 mol% TiO 2 , respectively. The present investigation revealed that the three-dimensional array of highly oriented crystalline Si 3 N 4 micro rods could be prepared which array on the homogeneous substrates by using TiO 2 as agent. This phenomenon may propose a method that the mechanical properties the Si 3 N 4 ceramics added TiO 2 can be improved significantly after annealing process. [ABSTRACT FROM AUTHOR]

Background: 9α-hydroxyandrost-4-ene-3,17-dione (9-OHAD) is a significant intermediate for the synthesis of glucocorticoid drugs. However, in the process of phytosterol biotransformation to manufacture 9-OHAD, product degradation, and by-products restrict 9-OHAD output. In this study, to construct a stable and high-yield 9-OHAD producer, we investigated a combined strategy of blocking Δ1‑dehydrogenation and regulating metabolic flux. Results: Five 3-Ketosteroid-Δ1-dehydrogenases (KstD) were identified in Mycobacterium fortuitum ATCC 35855. KstD2 showed the highest catalytic activity on 3-ketosteroids, followed by KstD3, KstD1, KstD4, and KstD5, respectively. In particular, KstD2 had a much higher catalytic activity for C9 hydroxylated steroids than for C9 non-hydroxylated steroids, whereas KstD3 showed the opposite characteristics. The deletion of kstDs indicated that KstD2 and KstD3 were the main causes of 9-OHAD degradation. Compared with the wild type M. fortuitum ATCC 35855, MFΔkstD, the five kstDs deficient strain, realized stable accumulation of 9-OHAD, and its yield increased by 42.57%. The knockout of opccr or the overexpression of hsd4A alone could not reduce the metabolic flux of the C22 pathway, while the overexpression of hsd4A based on the knockout of opccr in MFΔkstD could remarkably reduce the contents of 9,21 ‑dihydroxy‑20‑methyl‑pregna‑4‑en‑3‑one (9-OHHP) by-products. The inactivation of FadE28-29 leads to a large accumulation of incomplete side-chain degradation products. Therefore, hsd4A and fadE28-29 were co-expressed in MFΔkstDΔopccr successfully eliminating the two by-products. Compared with MFΔkstD, the purity of 9-OHAD improved from 80.24 to 90.14%. Ultimately, 9‑OHAD production reached 12.21 g/L (83.74% molar yield) and the productivity of 9-OHAD was 0.0927 g/L/h from 20 g/L phytosterol. Conclusions: KstD2 and KstD3 are the main dehydrogenases that lead to 9-OHAD degradation. Hsd4A and Opccr are key enzymes regulating the metabolic flux of the C19- and C22-pathways. Overexpression of fadE28-29 can reduce the accumulation of incomplete degradation products of the side chains. According to the above findings, the MF-FA5020 transformant was successfully constructed to rapidly and stably accumulate 9-OHAD from phytosterols. These results contribute to the understanding of the diversity and complexity of steroid catabolism regulation in actinobacteria and provide a theoretical basis for further optimizing industrial microbial catalysts. [ABSTRACT FROM AUTHOR]

A fourth-order energy preserving composition scheme for multi-symplectic structure partial differential equations have been proposed. The accuracy and energy conservation properties of the new scheme were verified. The new scheme is applied to solve the multi-symplectic sine-Gordon equation with periodic boundary conditions and compared with the corresponding second-order average vector field scheme and the second-order Preissmann scheme. The numerical experiments show that the new scheme has fourth-order accuracy and can preserve the energy conservation properties well. [ABSTRACT FROM AUTHOR]

Residual protein in chitosan-based biomaterials may cause inflammation, allergy, and immune rejection after surgery, impeding their clinical application. Facile production of chitosan with ultra-low protein content (residual protein <0.2 %) is yet to be addressed. Herein, we proposed a one-step method for preparing chitosan with residue protein content <0.2 % by using hydrogen peroxide and sodium dodecyl sulfate, which is simple, time-saving, cost-effective, and acid/alkali-free. Notably, the molecular weight of chitosan can be reduced simultaneously. The effects of experimental parameters (i.e. hydrogen peroxide concentration (0.01 %–1 %), SDS concentration (5 %–20 %), and reaction temperature (50 °C–70 °C)) on the protein removal and molecular weight decrease were systematically analyzed by response surface methodology. The results show that temperature and H 2 O 2 concentration are the main parameters affecting the deproteinization of chitosan. Further characterizations on the resulting ultra-low protein residue chitosan revealed unchanged chemical structure, enhanced crystallinity, and reduced thermal stability. The proposed one-step deproteination method may have great potential for industrial mass production of ultra-low protein residue chitosan. [ABSTRACT FROM AUTHOR]

Pheretima vulgaris has been prescribed for the treatment of cardiovascular diseases in China for several hundred years in the form of dried powder in the clinic. However, the peptides with the potential antithrombotic activity of this source have never been reported. The total active proteins from Pheretima vulgaris were hydrolyzed by eight different commercial proteases and the alcalase hydrolysate showed the strongest thrombolytic activity. Four original thrombolytic peptides were isolated and characterized using bioactivity‐directed fractionation of the active hydrolysate. The amino acid sequences were identified as HEPLPEP (m/z 818.40076), EYPLPEP (m/z 844.39648), LGEPSVP (m/z 698.39648), and LLAPP (m/z 510.28043) by nanoLC‐ESI‐Orbitrap mass spectrometry with PEAKS software. HEPLPEP and EYPLPEP, containing the common ‐PLPEP residue, showed superior thrombolytic activity in plasmin assay and fibrinogen‐thrombin time assay. This research confirmed that Pheretima vulgaris was a potential source of active peptides with thrombolytic activities and provided novel candidates for the thrombolytic agents. Practical applications: Thrombosis has become the leading cause of mortality as it was the common underlying pathology of cardiovascular diseases, such as ischemic heart disease, and stroke. The demand for thrombolytics has increased gradually as the incidence trends of thrombosis‐related diseases raise with the aging of the population. Four novel thrombolytic peptides were characterized from Pheretima vulgaris proteins hydrolysates, among which HEPLPEP and EYPLPEP could prevent the formation of thrombus and degrade existing thrombus in vitro. These peptides are promising to be meritorious templates for developing thrombolytic agents. The structure–function relationship of peptides resulting from the presence of specific residues in these sequences may contribute to extending the knowledge about their thrombolytic activity, which may be useful in designing novel thrombolytic agents. The present research based on a bioactivity‐directed isolation strategy could also be applied to other animal‐derived traditional Chinese medicines with proteins or peptides as their function basis. [ABSTRACT FROM AUTHOR]

• An interfacial diffusion induced gelation strategy is developed for cationic nanofluidics. • The ionic cables feature favorable strength (131 MPa) and aligned networks. • The ionic cables exhibit surface-charge-governed ion transport and anion selectivity. Due to the unique behavior of ion transport within confined nanochannels, nanofluidics has gained ever-increasing popularity in power generation, desalination, sensor and DNA sequencing. Both the anionic and cationic nanofluidic devices are of importance in their practical applications as the movement of the ions can be effectively regulated by the surface charge of the nanochannels. However, the emerging technology primarily focuses on anionic nanofluidic devices, while the straightforward, scalable and economical fabrication of cationic nanofluidic devices remains challenging. Herein, a bottom-up approach to aligned cationic nanofluidic films/cables, which fully harnesses the inherent positive charges on chitosan chains, is proposed. The cationic nanofluidic films are prepared directly through the ionic crosslinks between positively charged chitosan chains and negatively charged sodium dodecyl sulfate micelles via interfacial-diffusion-induced gelation, which feature favorable optical transparency, flexibility, thermal stability, tensile strength, anti-swelling ability, long-term stability and environmental tolerance. Furthermore, the resulting films can be stretched into aligned films and further twisted into ionic cables with a tensile strength of 131 MPa. Thanks to the well-aligned nanofluidic channels and the inherently positively-charged surface, the ionic cables exhibit a surface-charge-governed ion transport phenomenon as well as anion selectivity. The ionic conductivity of the ionic cable reaches 2.4 × 10−4 S·cm−1 at low salt concentrations (4.1 × 10−4 S·cm−1 for aligned films). This work not only provides a straightforward, scalable, cost-effective strategy for cationic nanofluidic devices through leveraging the inherent properties of natural polymers, but also offers promising opportunities for the underutilized biomass to be transformed into value-added products. [ABSTRACT FROM AUTHOR]

The synergism of dual-functional effect of Sn, optimized electronic structure by the ligand effect, and unique atomic arrangement endow the dendritic intermetallic PtSnBi nanoalloys high electrocatalysis toward MOR and EOR with enhanced CO tolerance. [Display omitted] Developing effective and robust novel electrocatalysts for direct alcohol fuel cells has been gaining much attention. However, the widely used Pt catalyst suffers from limitations including the sluggish kinetics, severe CO poisoning, and catalyst lost caused by aggregation and Ostwald ripening during alcohol oxidation reaction. Herein, dendritic intermetallic PtSnBi nanoalloys were synthesized via a facile hydrothermal approach with high electrocatalytic performance and enhanced CO resistance for methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR) owing to the synergism of the chosen three elements and unique three-dimensional morphology. Specifically, the PtSnBi nanoalloys display 4.6 and 6.7 times higher of mass activity (7.02 A mg−1 Pt) and specific activity (16.65 mA cm−2) toward MOR than those of commercial Pt/C, respectively. The mass activity of PtSnBi nanoalloys still retains 75.7% of the initial value after 800 cycles of stability test, superior to Pt/C (38.0%). The dual-functional effect of Sn, optimized electronic structure by the ligand effect, and unique atomic arrangement are responsible for the enhanced MOR activity and stability of PtSnBi nanoalloys. Furthermore, the PtSnBi nanoalloys with highlighted anti-CO poisoning capacity also improve the electrocatalytic performance toward EOR, indicating their great promise as broad energy electrocatalysts. [ABSTRACT FROM AUTHOR]

Pheretima is a common and valuable animal-derived medication used in traditional Chinese medicine. There are four species of Pheretima specified in the Chinese Pharmacopoeia (2015 edition), i.e. Pheretima aspergillum, P. vulgaris, P. guillelmi, and P. pectinifera. A recent report revealed ~ 55% of Pheretima in the commercial marketplace may be adulterated by other species, contrary to the Pharmacopoeia standard. The safety, efficacy, and authenticity of Pheretima is an important issue. Currently, the availability of specific quality-markers for the various species and effective identification methods are still limited. In this study, label-free quantification proteomics of species from Pheretima and Amynthas was carried out using nanoscale liquid chromatography coupled to tandem mass spectrometry (nano LC-MS/MS), and marker peptides were identified based on their ion intensities using multivariate data analysis (principal component analysis and supervised partial least-squares discriminant analysis). A total of 48,476 peptides with high confidence corresponding to 13,397 proteins were identified from all samples. The marker peptides were validated by comparison with synthetic peptide reference standards using LC-MS/MS operating in a multiple-reaction monitoring mode. A multiple-peptide identification strategy was proposed for the authentication of Pheretima and subsequently applied to samples obtained from retail outlets in various regions of China. The results showed that eight out of the 15 samples tested were deemed authentic Pheretima. [ABSTRACT FROM AUTHOR]

Purpose: The paper aims to (1) explore the positive and negative sociocultural, economic, and environmental impacts on satisfaction, and behavioral intentions; and (2) examine the changes in relationships among event impacts, satisfaction and behavioral intentions of host city residents before and after a major sporting event. Design/methodology/approach: We used panel data to estimate how resident responses change over time. The data were collected three months before (N before = 266) and three months after (N after = 266) the Nanjing Youth Olympic Games. Data were analyzed by confirmatory factor analysis (CFA), structural equation modeling (SEM) and invariance tests. Findings: A significant relationship exists between negative and positive perceived sociocultural, economic, and environmental impacts, satisfaction and behavioral intentions. In addition, findings suggest that the effect of the sociocultural impacts on satisfaction and of satisfaction on behavioral intentions strengthened after the event. The relationship between positive environmental impacts and satisfaction was reduced across the two points in time. Our results indicate that residents' assessment regarding the sporting event partially changed over the whole six-month course of the study. Originality/value: This study differs from most recent research in that it examines the sociocultural, economic, and environmental event impacts in modeling residents' satisfaction and testing the influence of negative event impacts on residents' satisfaction and behavioral intentions. The current study contributes to the literature by emphasizing the changes that occur regarding the relationships among event impacts, satisfaction and behavioral intentions across the same respondents over time. [ABSTRACT FROM AUTHOR]

With the development of low‐wind‐speed technology, it becomes a trend that low‐wind‐speed wind turbine generators (LWTGs) are integrated into a microgrid. However, the frequency stability of the microgrid has thereby been challenged since the increased penetration of wind power lowers the inertia of the microgrid. In order to investigate how LWTGs can effectively participate in suppressing the frequency fluctuation of the microgrid, virtual inertia control, over‐speed control, as well as droop control, is applied to LWTG. Moreover, the de‐loading ratio of over‐speed control, along with the control parameters of virtual inertia control and droop control are all optimised under different wind speeds by virtue of the deep belief network, whereas the problem of over‐speed control failure with the scheme of fixed de‐loading ratio becomes more pronounced under low‐wind speeds, which is defined as a blind area problem. To solve this problem, on the one hand, the strategy of the variable de‐loading ratio is adopted under low‐wind‐speeds. On the other hand, the concepts of the minimum and maximum critical wind speed are deduced through theoretical analysis, which greatly restricts the number of feasible solutions of de‐loading ratio under different wind speeds so as to improve the optimisation efficiency about 50%. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the mechanical properties and coloration of silicon nitride ceramics in the presence of RE 2 O 3 (RE = Nd, Eu or Dy). Dense Si 3 N 4 ceramics were prepared by gas pressure sintering at 1800 °C for 2 h. XRD analysis confirmed the complete transformation of α-Si 3 N4 to β-Si 3 N 4. The fracture toughness and flexure strengths were 11.93 ± 0.56 MPa·m1/2, 667 ± 40.98 MPa with the addition of Eu 2 O 3 (SE). Base on the SEM image, the pull-out, bridging and deflection of large grains were observed and contributed to the increase in mechanical properties. The chromaticity of sintered bodies was measured using a spectrophotometer. The color difference of the ceramics is due to the formation of different color developing compounds according to the EDS. Results showed that high-toughness and colorful Si 3 N 4 ceramics can be prepared using YAG:Ce3+ as sintering additive and RE 2 O 3 as the colorant. [ABSTRACT FROM AUTHOR]

Silicon nitride ceramics were pressureless sintered at low temperature using ternary sintering additives (TiO2, MgO and Y2O3), and the effects of sintering aids on thermal conductivity and mechanical properties were studied. TiO2–Y2O3–MgO sintering additives will react with the surface silica present on the silicon nitride particles to form a low melting temperature liquid phase which allows liquid phase sintering to occur and densification of the Si3N4. The highest flexural strength was 791(±20) MPa with 12 wt% additives sintered at 1780°C for 2 hours, comparable to the samples prepared by gas pressure sintering. Fracture toughness of all the specimens was higher than 7.2 MPa·m1/2 as the sintering temperature was increased to 1810°C. Thermal conductivity was improved by prolonging the dwelling time and adopting the annealing process. The highest thermal conductivity of 74 W/(m∙K) was achieved with 9 wt% sintering additives sintered at 1810°C with 4 hours holding followed by postannealing. [ABSTRACT FROM AUTHOR]

A new oxyphenisatin analogue was detected from a processed plum claiming to be a weight loss product without any side effects during the daily inspecting and monitoring of illegal adulterants in health supplements. An abundant peak caused our interest firstly owing to its identical fragments of m/z 224 and 196 in the MS/MS experiments with those of oxyphenisatin acetate. The chemical structure of the unknown compound was characterized by ultra-high performance liquid chromatography equipped with diode array detector and quadrupole time-of-flight tandem mass spectrometry (UHPLC-DAD-Q-TOF/MS), followed by nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy experiments. Based on the data, it was defined that the two symmetrical acetyl groups in oxyphenisatin acetate were replaced by two propionyl groups for the unknown structure. Finally, the new oxyphenisatin analogue was identified as 3,3-bis[4′-(propionyloxy)phenyl]−1,3-dihydroindole-2-one and designated as oxyphenisatin propionate. Thereafter, the content of the new analogue was quantitatively determined to be 681 mg/kg, which would inevitably cause adverse health effect because there was not specification for daily consumption of this product. To the best of our knowledge, this is the first report for identification of oxyphenisatin propionate. • A new oxyphenisatin analogue was isolated and characterized. • Oxyphenisatin propionate is a new illegal additive in weight loss products. • The data provides important references to identify new oxyphenisatin analogues. [ABSTRACT FROM AUTHOR]

Biocompatible coatings that can protect metal implants have great potential in tissue engineering. In this work, MWCNT/chitosan composite coatings with hydrophobic-hydrophilic asymmetric wettability were facilely prepared by one-step in situ electrodeposition. The resultant composite coating exhibits excellent thermal stability and mechanical strength (0.76 MPa), benefiting from the compact internal structure. The thickness of the coating can be controlled precisely by the amounts of transferred charges. The MWCNT/chitosan composite coating demonstrates a lower corrosion rate due to its hydrophobicity and compact internal structure. Compared with exposed 316 L stainless steel, its corrosion rate is reduced by two orders of magnitude from 3.004 × 10−1 mm/yr to 5.361 × 10−3 mm/yr. The content of iron released from 316 L stainless steel into the simulated body fluid drops to 0.1 mg/L under the protection of the composite coating. In addition, the composite coating enables efficient calcium enrichment from simulated body fluids and promotes the formation of bioapatite layers on the coating surface. This study contributes to furthering the practical application of chitosan-based coatings in implant anticorrosion. [Display omitted] • MWCNT/Chitosan composite coating is facilely fabricated by one-step electrodeposition. • The composite coating exhibits asymmetric wettability, enhanced thermal stability and mechanical properties. • The electrodeposited composite coating demonstrates outstanding anticorrosion performance. • The composite coating can promote the formation of a bioapatite layer on the coating surface. [ABSTRACT FROM AUTHOR]

• Pt site-selective PdPtM (M = Co, Ni, Fe) nanocrystals were fabricated by a cation-mediated strategy. • The reduction kinetics of the Pt precursor is precisely regulated under the assistance of metal cations. • The relationship between the deposition rate and diffusion rate of Pt atoms can be manipulated. • These PdPtM nanocrystals exhibit superior electrocatalytic performance towards ORR, EGOR, and GOR. Precisely structure-controlled Pt-based multimetallic nanocrystals represent one of most promising candidates in the realm of electrocatalysis, but their rational design and engineering have been restricted. Herein, a cation-mediated strategy is reported for exquisitely manipulating Pt sites on Pd hexagonal nanosheets by regulating the reduction kinetics of the Pt precursor. The key is to introduce metal cations (Co3+, Ni2+, Fe3+), which not only coordinate the relationship between the deposition rate and diffusion rate of Pt atoms but also act as dopants to optimize the electronic structure of nanomaterials. As a result, a series of PdPtM (M = Co, Ni, Fe) nanostructures, including alloy nanorings (PdPtCo NRs), core–shell nanosheets with Pt-rich shells (PdPtNi CS-NSs), and Pt-rich nanoparticle-decorated nanosheets (PdPtFe NP-D NSs), are successfully constructed. Impressively, these Pt site-selective nanocrystals remarkably boost the oxygen reduction reaction (ORR), ethylene glycol oxidation reaction, and glycerol oxidation reaction performance. In particular, the optimal PdPtCo NRs deliver the highest ORR mass and specific activities of 2.18 A mg−1 Pd+Pt and 3.23 mA cm−2 at 0.9 V vs. RHE, enhanced by 21.8 and 20.2 times, respectively, compared to those of commercial Pt/C. The excellent ORR stability of this catalyst is corroborated by the negligible changes after 15,000 cycles. This cation-mediated strategy may pave a new avenue to develop high-efficiency catalysts for energy-related applications. [ABSTRACT FROM AUTHOR]

Androst-4-ene-3,17-dione (AD) and 22-hydroxy-23,24-bisnorchol-4-ene-3-one (4-HBC) are important drug intermediates that can be biosynthesized from phytosterols. However, the C9 hydroxylation of steroids via 3-ketosteroid 9α-hydroxylase (KSH) limits AD and 4-HBC accumulation. Five active KshAs, the oxidation component of KSH, were identified in Mycobacterium fortuitum ATCC 35855 for the first time. The deletion of kshAs indicated that the five KshA genes were jointly responsible for C9 hydroxylation during phytosterol biotransformation. MFKDΔkshA, the five KshAs deficient strain, blocked C9 hydroxylation and produced 5.37 g/L AD and 0.55 g/L 4-HBC. The dual function reductase Opccr knockout and 17β-hydroxysteroid dehydrogenase Hsd4A enhancement reduced 4-HBC content from 8.75 to 1.72% and increased AD content from 84.13 to 91.34%, with 8.24 g/L AD being accumulated from 15 g/L phytosterol. In contrast, hsd4A and thioesterase fadA5 knockout resulted in the accumulation of 5.36 g/L 4-HBC from 10 g/L phytosterol. We constructed efficient AD (MFKDΔkshAΔopccr_hsd4A) and 4-HBC (MFKDΔkshAΔhsd4AΔfadA5) producers and provided insights for further metabolic engineering of the M. fortuitum ATCC 35855 strain for steroid productions. Key points: • Five active KshAs were first identified in M. fortuitum ATCC 35855. • Deactivation of all five KshAs blocks the steroid C9 hydroxylation reaction. • AD or 4-HBC production was improved by Hsd4A, FadA5, and Opccr modification. [ABSTRACT FROM AUTHOR]

Si3N4 ceramics have been attractive casing materials for electronics devices under the 5th generation mobile communication technology because of its outstanding comprehensive properties. However, single color cannot meet the needs of most consumers. Here, a typical strategy, involving forming core‐shell structures by utilizing Nd2O3‐MgO‐YAG system, is proposed to rich color. Scanning transmission electron microscope‐energy dispersive X‐ray spectrometry results confirm the presence of core‐shell structures in the silicon nitride matrix, and the core is pore and the shell is Nd‐enriched liquid phase. The Nd‐rich core‐shell structure as the color center makes the silicon nitride appear cyan or blue. [ABSTRACT FROM AUTHOR]

The FeOOH-150 nanorod with Lewis acid-base pairs (LPs) on the surface could effectively drive the nitrogen reduction reaction. PEG was introduced to serve as a local non-aqueous electrolyte system to inhibit HER, and DFT calculations revealed that the interaction of PEG with LPs can optimize nitrogen adsorption configuration and promoted eNRR process. [Display omitted] Ammonia (NH 3) synthesis at mild conditions by electrocatalytic nitrogen reduction (eNRR) has received more attention and has been regarded as a promising alternative to the traditional Haber–Bosch process. Lewis acid-base pairs (LPs) can chemisorb and react with nitrogen by electronic interaction, while the tuning of the microenvironment near electrode can hinder hydrogen evolution reaction (HER) thus improving the selectivity of the eNRR. Herein, the FeOOH nanorod coupled with LPs on the surface (i.e., Fe, Fe–O) was synthesized, which could effectively drive eNRR. Meanwhile, polyethylene glycol (PEG) was introduced to serve as a local non-aqueous electrolyte system to inhibit HER. The prepared FeOOH-150 catalyst achieved outstanding eNRR performance with an NH 3 yield rate of 118.07 μg h−1mg cat −1 and a Faradaic efficiency of 51.4 % at −0.6 V vs. RHE in 0.1 M LiClO 4 + 20 % PEG. Both the experiment and DFT calculations revealed that the interaction of PEG with Lewis base sites could optimize nitrogen adsorption configuration and activation. [ABSTRACT FROM AUTHOR]

TiO 2 -MgO is proposed as new sintering additive for low temperature pressureless sintering of Si 3 N 4 ceramics to be circuit substrate in power electronic devices. The effects of additive content on densification, mechanical and thermal properties of Si 3 N 4 substrate were investigated systemically. Si 3 N 4 ceramics with density of 3.20 g cm −3 could be obtained with the addition of 10 wt% TiO 2 -MgO and sintered at 1780 °C. The flexural strength, fracture toughness and thermal conductivity were 668 MPa, 5.13 MPa m 1/2 and 55.3 W/(m K), respectively, and the highest thermal conductivity was 60 W/(m K) could be obtained after annealing. Phase compositions at different temperature were characterized by high temperature in-situ XRD. TiC 0.3 N 0.7 s phase was observed and its formation mechanism was investigated. Results showed TiO 2 -MgO to be effective sintering additive for developing Si 3 N 4 ceramics at low cost and with acceptable mechanical and thermal properties. [ABSTRACT FROM AUTHOR]

Key message : A Salvia miltiorrhiza R2R3-MYB gene, SmMYB9b , has been cloned and characterized. Overexpression of SmMYB9b resulted in a significant improvement of tanshinones, the lipophilic active ingredients in danshen hairy roots. Abstract: Plant R2R3-MYB transcription factors play important roles in various physiological and biochemical processes. Danshen ( Salvia miltiorrhiza bunge) is a valuable medicinal herb with tanshinones and salvianolic acids as the principal bioactive ingredients. A number of putative R2R3-MYB transcription factors have been identified in the plant, but their function remains to be studied. Here, we report the cloning of SmMYB9b, an S20 R2R3-MYB member and its regulatory properties. SmMYB9b contains an open reading frame of 792 bp in length and encodes a 264-amino acid protein. Its transcripts were most abundant in blooming flowers (except for calyces) and increased with flower development. Exogenous abscisic acid strongly activated its transcription. Gibberellins and methyl jasmonate also showed a time-dependent activation effect on its transcription, but to a weaker degree. Overexpression of SmMYB9b in danshen hairy roots enhanced tanshinone concentration to 2.16 ± 0.39 mg/g DW, a 2.2-fold improvement over the control. In addition to increased tanshinone concentration, the hairy root growth and lateral hairy root formation were also suppressed. KEGG pathway enrichment analysis with de novo RNAseq data indicated that stress-response-related metabolic pathways, such as the terpenoid and plant hormone signal transduction pathways, were significantly enriched, implying possible implication of SmMYB9b in such processes. Quantitative RT-PCR analysis showed that the transcription of terpenoid biosynthetic genes SmDXS2, SmDXR, SmGGPPS, and SmKSL1 was significantly up-regulated in danshen hairy roots over expressing SmMYB9b. These data suggest that overexpression of SmMYB9b results in enhanced tanshinone concentration through stimulation of the MEP pathway. The present findings shed new light on elucidating the roles of R2R3-MYB in the biosynthesis of diterpenoids in S. miltiorrhiza. [ABSTRACT FROM AUTHOR]

In this paper, tape casting of Si3N4 substrate were investigated and optimized. The effects of dispersant content, binder, plasticizer/binder ratio, and solid loading on the green sheet properties were studied. An optimal formulation for the tape casting slurries was proposed, green tape with homogeneous microstructure and higher relative density of 56.08% was developed. After gas-pressure sintering and annealing, Si3N4 substrate with a relative density of above 99% and thermal conductivity as 58 W/m/K was obtained. Results showed that the combination of tape casting and gas-pressure sintering is feasible for the development of Si3N4 circuit substrates for power electronic devices. [ABSTRACT FROM AUTHOR]

We examine the effects produced by replacing B–B interlayer bonds by C–C bonds in AlMgB 14 -related boron network on its mechanical properties. The elastic constants, Vickers hardness and shear strength are evaluated by means of first principle computer simulations on the basis of density functional theory. The results of simulations suggest a possibility of existence of several orthorhombic boron carbide phases with strongly enhanced mechanical properties with the Young's modulus and Vickers hardness being within the range of 550–600 GPa and 43–50 GPa, respectively. [ABSTRACT FROM AUTHOR]

Xueshuantong Injection (XSTI), derived from Notoginseng total saponins, is a popular traditional Chinese medicine injection for the treatment of thrombus-resultant diseases. Current knowledge on its therapeutic basis is limited to five major saponins, whereas those minor ones are rarely investigated. We herein develop an offline two-dimensional liquid chromatography/quadrupole time-of-flight mass spectrometry-fast data directed analysis (offline 2D LC/QTOF-Fast DDA) approach to systematically characterize the saponins contained in XSTI. Key parameters affecting chromatographic separation in 2D LC (including stationary phase, mobile phase, column temperature, and gradient elution program) and the detection by QTOF MS (involving spray voltage, cone voltage, and ramp collision energy) were optimized in sequence. The configured offline 2D LC system showed an orthogonality of 0.84 and a theoretical peak capacity of 8976. Total saponins in XSTI were fractionated into eleven samples by the first-dimensional hydrophilic interaction chromatography, which were further analyzed by reversed-phase UHPLC/QTOF-Fast DDA in negative ion mode. The fragmentation features evidenced from 36 saponin reference standards, high-accuracy MS and Fast-DDA-MS 2 data, elemental composition ( C < 80, H < 120, O < 50), double-bond equivalent (DBE 5–15), and searching an in-house library of Panax notoginseng , were simultaneously utilized for structural elucidation. Ultimately, 148 saponins were separated and characterized, and 80 have not been isolated from P. notoginseng . An in-depth depiction of the chemical composition of XSTI was achieved. The results obtained would benefit better understanding of the therapeutic basis and significant promotion on the quality standard of XSTI as well as other homologous products. [ABSTRACT FROM AUTHOR]

Due to mechanical instability, surface wrinkles form spontaneously in plants, animals and human beings for propagation and enhanced surface functionality. However, there remains tremendous challenge in mimicking such exquisite structure at a micro/nanoscale in lab. Herein, we report an approach to converting an electrodeposited chitosan hydrogel film into a hollow tube with controllable wrinkle wavelength and amplitude via soaking the film in acidic sodium dodecyl sulfate (SDS). Notably, wrinkled pattern can be controlled by a self-design device through modulating the shrinkage ratio. The resultant wrinkled hydrogel tube with adjustable wall thickness, outer diameter shows excellent mechanical strength, anti-fatigue ability, recoverability and flexibility. It is demonstrated that 2D/3D complicated hollow framework with wrinkled pattern can be customized on demand. This facile strategy not only provides a feasible approach to preparing hydrogel tube with wrinkles, but also points to possible pathways for bioengineering more complicated materials from natural polymers. [Display omitted] [ABSTRACT FROM AUTHOR]

Animal-derived medicines have been a vital component for traditional Chinese medicine. However, their quality control remains challenging due to the large polarity of the contained endogenous small molecules (ESMs) that are difficult to separate by reversed-phase HPLC. Herein, an intelligentized strategy by ultra-high performance hydrophilic interaction chromatography/quadrupole time-of-flight mass spectrometry (HILIC/QTOF-MS) is presented, and used for the ESMs characterization and differentiation of two geographic origins of earthworm (Guang Di-long, GD; Hu Di-long, HD) as a case study. Chromatographic separation was performed on a BEH Amide column (2.1 × 100 mm, 1.7 μm). The MS data in both negative and positive ion modes were acquired to record the high-accuracy MS and MS/MS data of all precursor ions. Automatic data processing was enabled by use of Progenesis QI software. As a consequence, 926 metabolites among 4705 features and 761 among 3418 features were characterized in the negative and positive modes, respectively, by searching the human metabolome database (HMDB). To reduce the false positive identifications, structural confirmation was conducted by comparison with the reference standards (t and MS, MS/MS data) or matching with theoretical data or commercial library. Principal component analysis (PCA) of the GD and HD samples showed distinct classifications. Further orthogonal partial least squares discriminant analysis (OPLS-DA) and variable importance in projection (VIP) plot revealed the potential discriminatory markers between GD and HD. The present study provides a powerful and practical strategy that facilitates the primary metabolites characterization and quality evaluation of animal-derived medicines more efficiently. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The preparation of concentrated suspensions with high stability is crucial for tape casting. Dispersant plays an important role in the developing of high solid loading slurries with low viscosity. In this study, castor oil, phosphate ester and castor oil phosphate were selected as dispersants for alumina suspensions. The interaction between dispersant and alumina powders was characterized in terms of adsorption and viscosity measurements. Results showed that castor oil phosphate is more effective dispersant for alumina slurries. The influence of dispersant content, binder content, plasticizer/binder ratio and solid loading on the green sheet and mechanical properties of as-sintered alumina samples were also investigated. It was shown that the optimized formulation for dispersant, binder, plasticizer/binder ratio and solid loading was 2.22 wt%, 5.90 wt%, 1.0 and 31 vol%, respectively. Alumina ceramics showed improved mechanical properties, with the indentation hardness and fracture toughness as 15.91±0.15 GPa and 4.29±0.06 MPa m 1/2 , respectively. [ABSTRACT FROM AUTHOR]

In this study, the coherent structures, which were effected by superhydrophobic (SH) surfaces in turbulent channel flow, were investigated by time-resolved particle image velocimetry (TRPIV). Hierarchical structured SH surfaces which have micro-nano secondary structures were applied in the experiment. Drag reduction rate is approximately 11% at Re θ ≅ 1300 , which is based on momentum thickness. Coherent structures (low-speed streak, hairpin vortex and hairpin vortex packets) with scale information were obtained by conditional sampling and averaging method. Compared to the hydrophilic (PH) surfaces, the conditional averaged hairpin vortex structures of SH surfaces have a lager spacing of vortex legs, a smaller angle of inclination along streamwise and spanwise directions. Accordingly, a smaller-scale hairpin vortex packet with three swirling motions was emerged. Through the comparative research on angle of inclination, the lifting movement of vortex in wall-normal direction was also weaker than PH case. These shows that the existence of SH surfaces restricts the development of coherent structures and induces drag reduction effects. [ABSTRACT FROM AUTHOR]

Pearls have been widely used as a traditional medicine, in cosmetics, and as a health food supplement in China since ancient times. However, the identification and quality assessment of pearl powder have been challenging tasks because of the similar morphological features and chemical composition of its common adulterants, especially conch powders. In this study, ultra-performance liquid chromatography was combined with pre-column derivatization to rapidly quantify 14 amino acids in pearl powder and its analogues. Based upon the quantification results, a quality criterion of a total amino acid content of not less than 1.10% was proposed for pearl powder. Principal component analysis indicated that leucine and phenylalanine were the amino acids characteristic for distinguishing between pearls and nacres. The area ratio of leucine to phenylalanine was demonstrated to be an effective diagnostic marker to discriminate freshwater cultured pearls, natural seawater pearls, and nacres. The proposed method, involving both the qualitative and quantitative aspects, was subsequently applied to quality assessment of pearl powders purchased commercially in various parts of China; eight out of 18 batches were deemed authentic and unadulterated. In the future, this analytical process should play a significant role in standardizing and providing quality control to the pearl powder market. [ABSTRACT FROM AUTHOR]

Chinese patent medicines (CPM), generally prepared from several traditional Chinese medicines (TCMs) in accordance with specific process, are the typical delivery form of TCMs in Asia. To date, quality control of CPMs has typically focused on the evaluation of the final products using fingerprint technique and multi-components quantification, but rarely on monitoring the whole preparation process, which was considered to be more important to ensure the quality of CPMs. In this study, a novel and effective strategy labeling “retracing” way based on HPLC fingerprint and chemometric analysis was proposed with Shenkang injection (SKI) serving as an example to achieve the quality control of the whole preparation process. The chemical fingerprints were established initially and then analyzed by similarity, principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) to evaluate the quality and to explore discriminatory components. As a result, the holistic inconsistencies of ninety-three batches of SKIs were identified and five discriminatory components including emodic acid, gallic acid, caffeic acid, chrysophanol-O-glucoside, and p-coumaroyl-O-galloyl-glucose were labeled as the representative targets to explain the retracing strategy. Through analysis of the targets variation in the corresponding semi-products (ninety-three batches), intermediates (thirty-three batches), and the raw materials, successively, the origins of the discriminatory components were determined and some crucial influencing factors were proposed including the raw materials, the coextraction temperature, the sterilizing conditions, and so on. Meanwhile, a reference fingerprint was established and subsequently applied to the guidance of manufacturing. It was suggested that the production process should be standardized by taking the concentration of the discriminatory components as the diagnostic marker to ensure the stable and consistent quality for multi-batches of products. It is believed that the effective and practical strategy would play a critical role in the guidance of manufacturing and help improve the safety of the final products. [ABSTRACT FROM AUTHOR]

Cortex Lycii, the root bark of Lycium chinense Mill. or Lycium barbarum L., is a frequently used traditional Chinese medicine. Phytochemical studies have shown that phenolic amides are not only characteristic compounds but also abundant ones in this plant. In the present study, an effective method was developed for structural characterization of phenolic amides from Cortex Lycii by ultra-high performance liquid chromatography coupled with linear ion trap Orbitrap tandem mass spectrometry. The fragmentation of 14 compounds including six cinnamic acid amides, six neolignanamides, and two lignanamides were studied systematically for the first time. It was found that, in the positive ion mode, neutral loss of the tyramide moiety (137 Da) or N-(4-aminobutyl)acetamide moiety (130 Da) were characteristic for these compounds. At least 54 phenolic amides were detected in the extract and 48 of them were characterized, among which 14 known compounds were identified unambiguously by comparing the retention time and mass spectra with those of reference compounds, and 34 components were tentatively identified based on the fragmentation patterns, exact mass, UV spectra, as well as retention time. Fifteen compounds were characterized as potential new ones. Additionally, the developed method was applied to analyze eight batches of samples collected from the northwest of China, and it was found that cinnamic acid amides were the main type of phenolic amides in Cortex Lycii. In conclusion, the identification of these chemicals provided essential data for further phytochemical studies, metabolites identification, and the quality control of Cortex Lycii. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

In this paper, dense silicon carbide ceramics were prepared by aqueous gelcasting and pressureless sintering using dextrin as the carbon source. The influence of carbon content and solid content on the microstructure and mechanical properties of green and as sintered SiC samples was studied. It was shown that the carbon content should be 1 wt% or higher for the fully densification of silicon carbide ceramics. The influence of solid content on the green density and the mechanical properties of SiC ceramics was studied. The optimal solid content with 1 wt% carbon as sintering additives is around 52 vol%. Results showed that dextrin is an effective carbon source for developing SiC ceramics by aqueous gelcasting and pressureless sintering method. [ABSTRACT FROM AUTHOR]

Abstract: A composite of graphene oxide sheets, carbon nanotubes (CNTs), and commercial graphite particles was prepared. The composite’s use as a high-capacity and binder-free anode material for Li-ion batteries was examined. Results showed that this novel composite had a very high reversible Li-storage capacity of 1172.5mAhg−1 at 0.5C (1C =372mAg−1), which is thrice that of commercial graphite anode. The composite also exceeded the theoretical sum of capacities of the three ingredients. More importantly, its reversible capacity below 0.25V can reach up to 600mAhg−1. In summary, the graphene oxide/graphite/CNT composite had higher reversible capacity, better cycling performance, and similar rate capability compared with the graphene oxide/graphite composite. [Copyright &y& Elsevier]

Lipid accumulation in various microalgae has been found induced by nitrogen deprivation, and it controls many different genes expression. Yet, the underlying molecular mechanisms still remain largely unknown. MicroRNA (miRNAs) play a critical role in post-transcriptional gene regulation. In this study, miRNAs were hypothesized involved in lipid accumulation by nitrogen deprivation. A deep-sequencing platform was used to explore miRNAs-mediated responses induced by nitrogen deprivation in Chlamydomonas reinhardtii. The eukaryotic orthologous groups of proteins (KOG) function in the predicted target genes of miRNA with response to nitrogen deprivation were mainly involved in signal transduction mechanisms, including transcription, lipid transport, and metabolism. A total of 109 miRNA were predicted, including 79 known miRNA and 30 novel miRNA. A total of 29 miRNAs showed significantly differential expressions after nitrogen deprivation, and most of them were upregulated. A total of 10 miRNAs and their targeting genes might involve in lipid transport and metabolism biological process. This study first investigates nitrogen deprivation-regulated miRNAs in microalgae and broadens perspectives on miRNAs importance in microalgae lipid accumulation via nitrogen deprivation. This study provides theoretical guidance for the application of microalgae in bio-oil engineering production. [ABSTRACT FROM AUTHOR]

Abstract: A composite of graphite and graphene oxide is synthesized and used as a high capacity and binder-free anode material directly in lithium-ion batteries for the first time. The scanning and transmission electron microscope analyses of the composite show the graphite particles and conductive additive are homogeneously distributed on the graphene oxide surface. The X-ray photoelectron spectroscopy result indicates that the oxygen containing groups of graphene oxide have been partially reduced during the first discharge process. Electrochemical tests reveal that this composite has more than 690 mA h g−1 reversible capacity at the rate of 0.5 C (1 C = 372 mA g−1), simultaneously with excellent cycle performance and rate capability. [Copyright &y& Elsevier]

Abstract: In this paper, silicon carbide ceramics were prepared by aqueous gelcasting and pressureless sintering using Al2O3 and Y2O3 as the sintering additives. In order to develop well dispersed SiC slurries in the presence of sintering additives, the Al2O3 and Y2O3 powder was treated in the citric acid solution in advance. Zeta potential measurement showed that the isoelectric point (IEP) of Al2O3 and Y2O3 powder moved toward low pH region after treatment. Rheological measurement confirmed that the addition of as-treated powder showed very limited influence on the slurry properties as compared to that of untreated powder. SiC slurries with solid content of 54vol% and enough fluidity can be developed. After gelcasting and pressureless sintering, SiC ceramics with nearly full density, fine grained and homogeneous microstructure can be obtained. Results showed that the surface treatment of Al2O3 and Y2O3 with citric acid is effective for the gelcasting process of SiC. [Copyright &y& Elsevier]

Abstract: We demonstrate the synthesis of calcium phophate fluoride hybrid hollow spheres with well controlled size and morphology through self assembly process using Poly (ethylene oxide)–poly (propylene oxide)–poly (ethylene oxide) triblock copolymer (Pluronic P123) as the template. The diameter and the shell thickness of the hollow spheres is typically in the range of 100–600nm and 150–200nm respectively. Scanning electron microscope (SEM), Energy dispersive X-ray spectrometer (EDX), Transmission electron microscopy (TEM) and N2 adsorption–desorption analyses confirmed that well organized hollow spherical structures have been developed. The formation mechanism is attributed to the change in the hydrophobic–hydrophilic balance by the fluoride ions (F−). Our result provides a simple route for the synthesis of inorganic hollow spheres by templating strategies. [Copyright &y& Elsevier]

Abstract: In this paper, MWCNTs–SiC composites were prepared by non aqueous tape casting and hot pressing. The dispersion of MWCNTs was investigated and correlated to the Hansen solubility parameters. The microstructure and mechanical properties of the obtained MWCNTs–SiC composites were studied. It was found that the MWCNTs were retained after sintering. An improvement in toughness was resulted with the MWCNTs content as low as 0.25mass%. The present research provides a facile route for the preparation of ceramic–MWCNTs composites with improved properties. [Copyright &y& Elsevier]

Abstract: The nanocomposite of hematite@carbon nanosprings (α-Fe2O3@CNSs) was synthesized by simple precipitation and following heat treatment, in which the amount of α-Fe2O3 can be easily controlled by changing the synthesis conditions. Thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electronic microscopy (SEM), Brunau–Emmertt–Teller (BET), and X-ray photoelectron spectroscopy (XPS) were employed to characterize the as-synthesized nanocomposite. When applied as anode in Li-ion batteries (LIBs), the effect of α-Fe2O3/CNSs weight ratio on electrochemical performance of α-Fe2O3@CNSs nanocomposite has been researched. Enhancing the amount of α-Fe2O3 in nanocomposite would make the increase of specific capacity, but led to the degradation of cyclic stability and rate capability. The electrode of S-FeC (with weight ratio of CNSs/α-Fe2O3 about 4:1) could deliver a charge capacity of 527.6mAhg−1at 0.2C with excellent cyclability (96.9% capacity retention after 50 cycles), and retained 343.3mAhg−1even at the rate of 5.0C. In comparison with pure CNSs and α-Fe2O3, the improved cycling performance, specific capacity and rate capability of S-FeC should be mainly attributed to the combined effects of uniformly dispersed nanosized α-Fe2O3 particles and the highly strong network of CNSs. [Copyright &y& Elsevier]

Abstract: In this article, highly organized HA nanostructure was developed using a nonionic surfactant p-(1,1,3,3-tetramethylbutyl) phenoxypoly(oxyethylene) glycol (triton X-100) as the template. The obtained well-organized architectural units were examined using transmission electron microscopy (TEM), SEM, XRD and FTIR. High-resolution transmission electron (HRTEM) revealed that HA nanorods were well assembled in order along the c-axis. FTIR results indicated the possible interactions between triton X-100 and HA. The mechanism of the assembly of well-oriented nanostructure was proposed. The composites containing nanosized hydroxyapatite with structural features close to that of human bone should be useful and important for the practical applications, especially in the development of biomimetic materials. [ABSTRACT FROM AUTHOR]

Abstract: Mesostructured calcium phosphate was synthesized by means of the combination of a soluble metal salt with an aqueous phenylphosphonic acid solution containing sodium dodecyl sulfate (SDS). Phenylphosphonic acid (PhP) was selected as the template to pattern the materials with pores generated by the formation of a lamellar calcium PhP phase. SDS was introduced to improve the thermal stability of the pore structure. The resulting materials were characterized by means of X-ray diffraction (XRD), small-angle X-ray diffraction (SAXS), electron microscopes and BJH gas absorption method. With the aid of SDS, calcium phosphate materials with the surface area and pore volume as 72m2/g and 569cm3/g, respectively, were successfully developed at the SDS:PhP molar ratio of 0.3:1. It was found that the addition of SDS could effectively improve the thermal stability of the pore structure. A possible mechanism was proposed to interpret the formation procedure and the improved thermal stability of the mesoporous structure. [Copyright &y& Elsevier]

Abstract: Al2O3 ceramics were prepared through colloidal processing and consolidation process. Initially, Al2O3 powder was dispersed in aqueous medium to make 60vol% suspensions with 1.5wt% dispersant. After mixing to obtain well-dispersed slurries, a minor amount of sulfanilic acid was added and the slurries were consolidated in a nonporous mould. Al2O3 green samples exhibited a homogeneous microstructure with uniform distribution in pore size. After sintering at 1600°C in air, the microstructure, hardness and toughness were characterized. Toughness as high as 6.40MPam1/2 was obtained for Al2O3 samples with sulfanic acid/Al2O3 mass ratio as 5.74mg/g. Results showed that it was possible to consolidated Al2O3 slurries with homogeneous microstructure and high mechanical properties. [Copyright &y& Elsevier]

Abstract: This paper describes the preparation of hydroxyapatite ceramics through slip casting and pressureless sintering. Based on the surface properties of HAp powder, a combination of two components, polyacrylic acid sodium salt (PAA-Na) and l-glutamic acid (GA), was used as the dispersing agents. HAp slurries with the solid content as high as 63vol% could be prepared in the presence of the dispersants. After slip casting, green samples exhibited homogeneous microstructure. The samples were further densified at different temperature and soaking time. The microstructure, dehydroxylation behavior and mechanical properties were evaluated. In consideration of dehydroxylation, grain growth and blowhole development, it was found that 1250°C with 2h soaking is appropriate for sintering of HAp. Results showed that it was feasible to introduce l-glutamic acid as the second dispersant for improving the slurry stability and making more reliable HAp samples. [Copyright &y& Elsevier]

Dense hydroxyapatite–zirconia (HAp–ZrO2) composites are expected to have desired mechanical and biological properties for orthopedic applications. However, due to some processing problems, to date, this material can only be prepared by special techniques. In this paper, we report for the first time a facile route to prepare HAp–ZrO2 composites. Initially, HAp and ZrO2 powders were dispersed in aqueous media with polyacrylic acid and glutamic acid as the dispersants. The slurries exhibited a well-stabilized state at a high solid content (>50 vol%) and therefore green samples with high density (>60%) can be obtained after slip casting. These HAp–ZrO2 green samples can be easily densified by pressureless sintering at 1450°C with 2 h holding. After sintering, only hydroxyoxyapatite Ca10(PO4)6O x (OH)2(1− x) (HOA), ZrO2, and trace amounts of α-tricalcium phosphate phases were detected. No obvious reactions between HAp and ZrO2 phase were observed. The HAp–ZrO2 samples showed excellent mechanical and biological properties. For 40 vol% HAp–60 vol% ZrO2 samples sintered at 1450°C, the flexural strength and toughness were 220 MPa and 4.37 MPa·m1/2, respectively. In addition, we observed the attachment, spreading, and proliferation of mesenchymal stem cells on the HAp–ZrO2 samples' surface. The results showed that the proposed colloidal processing and pressureless sintering process is feasible for preparing HAp–ZrO2 composites with high mechanical properties and promising bioactivity for orthopedic applications. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes a study of the dispersion of hydroxyapatite (OHAp) powder in aqueous media. The slurry stability is achieved by utilizing a combination of a commercially available dispersant, polyacrylic acid sodium salt (PAA-Na) and ethylenediaminetetraacetic acid, tetrasodium salt, dihydrate (EDTA·4Na·2H2O). Adsorption, sedimentation and rheology measurements have been performed to investigate the suspensions properties. It was shown that HAp slurries could be stabilized at pH 10.50 with the PAA-Na concentration around 0.45wt%. Rheological measurement confirmed that well dispersed slurries could be obtained with the solid content as high as 63vol%. After sintering, the relative density of HAp sheets reached 98.8%. The as sintered HAp samples exhibited excellent properties for cell attachment and proliferation. Results showed that the aqueous processing technique is effective for preparation HAp samples for biological applications. [Copyright &y& Elsevier]

Abstract: Si3N4 samples were prepared by tape casting, laminating and hot pressing (HP)/spark plasma sintering (SPS). Initially, the as-received Si3N4 powders were chemically treated to improve the dispersion in aqueous media. After surface treatment, a decrease in zeta potential was observed in the basic region. Rheological measurements showed that 40vol.% Si3N4 slips exhibited a well deflocculated state in the presence of the sintering additives. After the addition of binder and plasticizer, Si3N4 slurries exhibited a shear thinning behavior. The dried green sheets were smooth and homogeneous on both sides. The Si3N4 samples were densified by HP and SPS. A good homogeneity is observed and no single layers can be distinguished in the fracture surface. The mechanical properties were also studied. [Copyright &y& Elsevier]

Abstract: Polyethylene imine (PEI) proved to be effective for dispersing SiC particles in aqueous media. However, SiC suspensions with only PEI as dispersant exist in a flocculated state at high solid content. In this study, citric acid is introduced as the second dispersant for improving the slurry stability. The adsorption behavior of both dispersants and the relevant slurry properties were characterized in terms of zeta potential, sedimentation, adsorption, FTIR and rheology measurements. In the presence of citric acid, an increase in zeta potential of SiC particles was observed in neutral and acid pH ranges. Adsorption measurement showed that the addition of citric acid could effectively enhance the adsorption of PEI on SiC particle surface, which might come from the formation of complexation between citric acid and adsorbed PEI, as evidenced by FTIR. Sedimentation and rheological measurements further confirmed that SiC slurries exhibited an improvement in stability upon the addition of citric acid. Results showed that the combination of PEI and citric acid as dispersants could effectively stabilize SiC suspensions at high solid content. [Copyright &y& Elsevier]