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Background: Psychological distress is reported to be associated with academic burnout in students while the mediation and moderation effect of resilience and personality are less explored. Purpose: The current study was designed to estimate the mediating effect of resilience and the moderation effect of personality between psychological distress and academic burnout. Participants and methods: A total of 613 students were enrolled from two medical universities between December 2020 and January 2021. They were administered with Academic Burnout Scale, 10-item Kessler Psychological Distress Scale (K10), Connor-Davidson Resilience Scale (CD-RISC-10) and NEO Five-Factor Inventory (NEO-FFI). Latent profile analysis and moderated mediation analysis were performed. Results: Three personalities were identified and named as resilient (13.4%), over-controlled (50.2%) and under-controlled (36.4%). Resilience significantly mediated the relationship between psychological distress and academic burnout while personality significantly moderated the relationship between psychological distress and resilience. Conclusion: Resilience and personality may be two important mediators between psychological distress and academic burnout. More attentions should be paid to students with under-controlled personality and resilience-enhancing interventions could be developed to prevent or alleviate academic burnout in future research. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A method to fabricate robust super-hydrophobic coating by spraying fluorine-free suspension. • Super-hydrophobic coating could against high-low temperature, UV light and chemical corrosion. • The coating can withstand mechanical tests such as knife scraping, and sandpaper abrasion cycles. • The coating has a self-healing, self-cleaning in air or oil and anti-corrosion performance. Abstract Some drawbacks such as complicated preparation processes, more expensive modification, and lack of durability have restricted the practical applications of super-hydrophobic coatings. In this paper, we present a simple and inexpensive approach to fabricating a robust super-hydrophobic coating by spraying a fluorine-free suspension composed of epoxy resin (EP), polydimethylsiloxane (PDMS), and modified SiO 2 on various substrates. This coating exhibited excellent super-hydrophobicity with a contact angle of 159.5° and a sliding angle of 3.8°. The as-prepared super-hydrophobic EP + PDMS@SiO 2 coating retained super-hydrophobicity after exposure to harsh conditions including immersion in boiling water for 2 h or liquid nitrogen for 1 h, intense UV radiation for 48 h, and intense chemical corrosion. Moreover, the resulting super-hydrophobic coating can withstand various mechanical durability experiments such as tape peeling after knife scraping, hand kneading, and 100 sandpaper abrasion cycles. Furthermore, the fabricated coatings also exhibit a self-healing ability against O 2 plasma etching, excellent self-cleaning in air and oil conditions and outstanding anti-corrosion performance. We believe that this easy, environmentally friendly method has great potential for large-scale practical applications in numerous fields. [ABSTRACT FROM AUTHOR]

Abstract A novel Mg-8Al-2Sn-1Zn alloy with a bimodal structure prepared by hard-pate-rolling (HPR) exhibits both higher tensile strength and ductility than its fine-grained counterparts prepared by conventional rolling. By delicate electron back-scatter diffraction (EBSD) analysis, we found fine grains with weak basal texture is beneficial for basal slip and favors initial deformation. Meanwhile, coarse grains with a strong basal texture could accommodate abundant newly generated dislocations, promoting work hardening after fine grains are saturated with dislocations. For the first time, individual roles of fine and coarse grains and their synergy effect on enhancing ductility in bimodal structured Mg alloys is clarified. Graphical abstract Image 1 Highlights • A bimodal grain-structured Mg alloy is fabricated by hard-pate-rolling. • The bimodal sample has higher strength and ductility than fine-grained samples. • The synergy effect of fine and coarse grains on enhancing ductility is clarified. [ABSTRACT FROM AUTHOR]

In this study, the structural stability and electronic properties of Al(111)/4H-SiC(0001) interface, as well as the effects of Ti, Si, Mg and Cu additions on the interfacial adhesive strength are investigated via the first-principles method. Surface energy calculations show that 4H-SiC(0001) with C-termination is more active than Si-termination. Moreover, polar covalent bonds are formed across Al/4H-SiC interface. The results of separation energies suggest that the introduction of Ti and Si can improve the adhesive strength of C-terminated Al(111)/4H-SiC(0001) interface, whereas Mg and Cu have the opposite effect. According to the analysis of interfacial electronic structure, the covalent bonds across Al/4H-SiC interface are further enhanced with the addition of Ti and Si atoms, contributing to the improved adhesive strength in this case. However, the interactions between interfacial atoms are weakened with Mg and Cu doped in C-terminated interface, which results in the decrease of interfacial adhesion strength. Our calculations provide a guide to experiments on the design of 4H-SiC reinforced Al-matrix composites with tailored properties. [ABSTRACT FROM AUTHOR]

The complex modification of primary Mg2Si in an Al–20Mg2Si alloy by simultaneous addition of yttrium (Y) and antimony (Sb) was investigated in the present work. It was found that the combined addition of 0.5 wt% Y–Sb had a more significant modifying effect than the single addition of an equivalent amount of Y or Sb. After modification, coarse Mg2Si dendrites were changed into fine polyhedra with an average size decreasing from 86 to less than 18 μm. It has been demonstrated that Sb participated in the formation of Mg3Sb2, which acts as a heterogeneous nucleus of primary Mg2Si and hence significantly refines their sizes. Meanwhile, Y could obviously adsorb and poison the preferred growth along the ＜100＞ directions of primary Mg2Si crystals, and hence not only changed their final morphology to a truncated octahedron but also reduced their sizes. Furthermore, the skeleton-type growth process of the truncated octahedral primary Mg2Si in the Al–20Mg2Si alloy co-modified by 0.5 wt% Y–Sb was also revealed. Our study provides a new insight into the design of more efficient modifiers by the combined addition of a refiner (e.g. Sb) and a growth inhibitor (e.g. Y), which is critical to tailor new light-weight alloys with high strength and toughness. [ABSTRACT FROM AUTHOR]

In this work, primary Mg2Si crystals shaped by {100} and {111} facets were successfully fabricated in Al–Mg–Si melts via the adsorption and poisoning of the Ca element. The modifier Ca plays an important role in determining the morphologies of primary Mg2Si, which can be transformed from dendrites (0 wt%) to crystals with a combination of eight {111} and four {100} facets (0.08 wt%), then to truncated cubes (0.1 wt%), and finally to cubes fully bounded by {100} facets (0.2 wt%) with increasing Ca content. The growth processes of cubic primary Mg2Si have been revealed. As the growth rates of {100} surfaces are diminished by adsorption of the Ca element, primary Mg2Si tends to form perfect cubes with exposed {100} facets. Moreover, by prudently adjusting the concentration of the Ca element, complex polyhedral crystals enclosed by {111} and {100} surfaces were designed and prepared. The results offer valuable insights into designing the modification effect of different modifying elements, which are critical to promoting the industrial application of light alloys with improved morphology and refined size of microstructures. [ABSTRACT FROM AUTHOR]

Effects of Zn addition on the microstructure and tensile properties of as-extruded Mg-8Al-2Sn (AT82) alloy were investigated in the present work. All the extruded AT82 alloys exhibited a fully dynamically recrystallized (DRXed) microstructure, while the grains were slightly refined with Zn addition. Moreover, second phase particles (Mg 2 Sn and Mg 17 Al 12 ) increased significantly in amount with increasing Zn content. It was found the ultimate tensile strength (UTS) and yield strength (YS) gradually increased with increasing Zn content from 0 to 1.5 wt%, meanwhile the elongation maintained unchanged at a high level, i.e. ~17–19%. In particular, the as-extruded AT82-1.0Zn alloy exhibited both a high strength and high ductility at room temperature, e.g. UTS of ~357 MPa and elongation of ~19%. The superior combination of strength and ductility is mainly benefited from the enhanced work-hardening ability resulted from Zn solid solutes and the presence of more well-dispersed fine particles in AT82-1.0Zn alloy. [ABSTRACT FROM AUTHOR]

In the present study, Mg-6Zn-1Zr (ZK60) alloy with a homogeneous fine-grained structure (~5 µm) was produced by hot extrusion. The influence of temperature on tensile properties anisotropy and the associated change in deformation mechanisms in the range of 25–275 °C of the fine-grained ZK60 alloy were investigated. Under room temperature, the fine-grained ZK60 alloy exhibited a high tensile strength of ~269–327 MPa and high ductility of ~15–39% when tested at three different directions, indicating a high anisotropy. With increasing testing temperature to 150 °C and further to 275 °C, the alloy showed a gradual decrease in anisotropy. Especially, the fine-grained ZK60 alloy exhibited superplasticity of ~376–434% when tested at 275 °C, which should be due to the increasing role of grain boundary sliding (GBS), as the strong basal texture associated with room temperature deformation became almost random at elevated temperatures. Moreover, the abrupt decrease in tensile anisotropy and associated change in texture with increasing temperature correlates closely to the transformation of deformation mode from a dislocation-dominated behavior to a GBS-mediated one. [ABSTRACT FROM AUTHOR]

In this work, primary Mg2Si crystals shaped by {100} and {111} facets were successfully fabricated in Al–Mg–Si melts via the adsorption and poisoning of the Ca element. The modifier Ca plays an important role in determining the morphologies of primary Mg2Si, which can be transformed from dendrites (0 wt%) to crystals with a combination of eight {111} and four {100} facets (0.08 wt%), then to truncated cubes (0.1 wt%), and finally to cubes fully bounded by {100} facets (0.2 wt%) with increasing Ca content. The growth processes of cubic primary Mg2Si have been revealed. As the growth rates of {100} surfaces are diminished by adsorption of the Ca element, primary Mg2Si tends to form perfect cubes with exposed {100} facets. Moreover, by prudently adjusting the concentration of the Ca element, complex polyhedral crystals enclosed by {111} and {100} surfaces were designed and prepared. The results offer valuable insights into designing the modification effect of different modifying elements, which are critical to promoting the industrial application of light alloys with improved morphology and refined size of microstructures. [ABSTRACT FROM AUTHOR]

The morphology evolution of primary Mg2Si in the Al–20Mg2Si–0.1Ca alloy was investigated by a mould temperature-controlled solidification technique at various solidification cooling rates. It is found that by lowering the pre-set mould temperature, i.e. increasing the cooling rates, the influence of external factors, i.e. the adsorption of Ca atoms on {100} facets, on the morphology evolution of primary Mg2Si can be strengthened, leading to primary Mg2Si with varying morphologies. With the decrease of mould temperature from 600 to 400 °C and then to 200 °C and finally to room temperature, primary Mg2Si transformed from a mixture of an equiaxed-dendrite and an octahedron to a truncated octahedron and then to a truncated cube and finally to a cube; in contrast, primary Mg2Si still remained dendritic in the Ca-free Al–20Mg2Si alloy. Moreover, the skeleton-type growth process of the truncated cubic primary Mg2Si in the modified alloy was identified, where growth steps with some hillocks were observed for the first time. Our study offers a simple and low-cost method to control the morphology and size of primary Mg2Si crystals in the Al–Mg–Si alloy, which is beneficial to the design of lightweight Al–Mg–Si alloys with high strength and toughness. [ABSTRACT FROM AUTHOR]

The morphology evolution of primary Mg 2 Si particles in a Al-20Mg 2 Si-4.5Cu alloy both unmodified and modified with 0.5 wt% Ca-Sb prepared by hot-extrusion followed by T6 heat treatment was investigated in the present study. Interestingly, we found that the combination of hot-extrusion and T6 heat treatment was efficient in transforming truncated octahedral primary Mg 2 Si into sphere in the modified alloy. In contrast, the primary Mg 2 Si particles still kept dentritic in the unmodified alloy. It suggested that the formation of truncated octahedral primary Mg 2 Si particles in as-cast state, the fragmentation of particles by hot-extrusion and the enhanced solid-state diffusion of Si and/or Mg atoms during heat treatment were responsible for the spheroidization of primary Mg 2 Si. Moreover, the existence of fine (~10–20 µm) spherical primary Mg 2 Si played an important role in strengthening the alloy, i.e., the ultimate tensile strength (UTS) increased from ~227 MPa in the unmodified alloy to ~303 MPa in the modified one. It is because the fine spherical primary Mg 2 Si particles can provide a higher fracture stress and strength of the matrix/particle interface. Our study offered a simple methodology to prepare spherical primary Mg 2 Si in an Al-high Mg 2 Si alloy, which is beneficial to design novel light-weight Al-Mg-Si alloys with improved mechanical properties. [ABSTRACT FROM AUTHOR]

Cast-rolling AZ31 Mg alloy sheets were manufactured at four rolling speed ratios of 0.8, 1.0, 1.2 and 1.3. The results show that the basal texture can be weakened by differential speed rolling (DSR). The AZ31 alloy sheet manufactured at a speed ratio of 1.2 exhibits a fine microstructure with an average grain size of 10.3 μm. The yield strength, ultimate tensile strength and elongation-to-failure at this speed ratio are 145 MPa, 240 MPa and 28.5% at room temperature, respectively. These parameters mainly benefit from the fine grains and weakened basal texture. The AZ31 alloy sheets processed by the DSR exhibit a remarkable improvement in elongation-to-failure compared with the AZ31 alloy sheets processed by equal speed rolling (ESR) primarily due to the weakened basal texture at room temperature. However, the difference in elongation-to-failure of the AZ31 alloy sheets processed by the ESR and DSR decreases at elevated temperatures, which can be attributed to the weakening of the influence of basal texture, with probable activation of non-basal slips and grain boundary sliding (GBS). The results obtained here will shed light on some DSR methods, which is critical to the development of Mg alloys with high mechanical properties. [ABSTRACT FROM AUTHOR]

The surface energies of Mg2Si (100) and (111) facets doped with modifying elements (Sb, Te, Sn, P and Bi) are calculated using first-principles methods, aimed at investigating the effects of the incorporation of modifying elements on the morphological evolution of Mg2Si. Based on the results of surface energy, the equilibrium shape of pure Mg2Si is predicted to be an octahedron surrounded by {111} planes. With the incorporation of Te, Sn, P and Bi, the ratio between the surface energies of the (100) and (111) planes (r) drops compared with that of pure Mg2Si, promoting the extension of the (100) facets and the contraction of the (111) facets on Mg2Si grains. Accordingly, the trend in morphological evolution for Mg2Si is from the initial octahedron composed of {111} planes to a truncated octahedron surrounded by {111} and {100} planes. The results also show that Te and P are more effective in promoting the appearance frequency of (100) facets on the Mg2Si crystal and can be used as candidate modifiers to realize the artificial manipulation of the morphology of Mg2Si into a truncated octahedron. The findings here provide new insights for understanding the morphological evolution of Mg2Si induced by the incorporation of modifying elements, which contributes to guiding the development of new high-temperature-resistant light alloys. [ABSTRACT FROM AUTHOR]

This work was carried out to investigate the relationship between microstructures and mechanical properties of extruded Al–20Mg 2 Si–4Cu alloys unmodified and modified with 0.5 wt% Sb addition at room and high temperatures. Various techniques including metallography, field emission scanning electron microscope, differential thermal analysis and scanning electron microscopy were used to characterize the microstructure, tensile behavior and fracture mechanism of the alloys. It was found that 0.5 wt% Sb additions were highly effective in refining microstructures by changing the morphology of primary Mg 2 Si from coarse dendrite into smaller polyhedral shape with average size less than 20 µm. Tensile test showed that ultimate tensile strength (UTS) of the modified alloy increased dramatically to 283 MPa at room temperature and 213 MPa at 150 °C, evidently higher than the 220 MPa and 185 MPa for the unmodified alloy, respectively. Fracture surface examinations revealed a transition from particle fracture of primary Mg 2 Si in the unmodified alloy to particle–matrix interface debonding in the modified alloy. The transformation of primary Mg 2 Si from coarse dendrites to refined polygonal shapes contributes to the enhanced strength and ductility of the modified alloy, since the polygonal primary Mg 2 Si particles dispersed uniformly in modified alloy, impeding dislocation motions and freeing stress concentrations. A schematic map was established to further elucidate the mechanisms of fracture behavior during stretching process. [ABSTRACT FROM AUTHOR]

Although many research efforts have been devoted to improving the electrochemical performance of ZnCo 2 O 4 , there is still a great need for a facile, low cost and time-saving method to synthesize ZnCo 2 O 4 . Herein, we first report a facile method to prepare mesoporous ZnCo 2 O 4 with polypyrrole (PPy) coating (ZnCo 2 O 4 /PPy). The facile strategy involves a reflux method and a subsequent chemical polymerization method. The mesoporous ZnCo 2 O 4 /PPy shows an outstanding electrochemical performance. The discharge capacity of the ZnCo 2 O 4 /PPy is 615 mAh g −1 after 100 cycles at a current density of 0.1 A g −1 . When the current density increases to 0.2 A g −1 , the discharge capacity still retains 458 mAh g −1 after 100 cycles. The improved electrochemical performance is attributed to the coating of PPy layer, which acts as a conductive agent and buffer during charge/discharge. Our results demonstrate that the ZnCo 2 O 4 /PPy has potential as a high-energy anode material for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Primary Mg2Si with a truncated octahedral morphology and size over a range of 8–15 μm were prepared by simultaneously adding Ca and Sb into the Al–Mg–Si melt. It is revealed for the first time that CaSb2 can act as the nucleus of primary Mg2Si during solidification, which changes the morphology and refines the size of primary Mg2Si significantly. It is useful for improving the mechanical properties of the Al–Mg–Si alloy. The skeleton-type growth processes of truncated octahedral primary Mg2Si crystals were identified by observation of the three-dimensional (3-D) morphologies of the crystals extracted from the Al–Mg–Si alloy. The content of Ca and Sb plays an important role in determining the morphologies of primary Mg2Si, which can be transformed from coarse dendrites to defective truncated octahedra and finally to the coexistence of perfect truncated octahedra and flat truncated octahedra with increasing the content from 0 to 0.2 and then to 0.5 wt%. Our study provided a one-step less-cost method to change the morphologies and sizes of primary Mg2Si, which is important to tailor new light-weight alloys with high strength and toughness. [ABSTRACT FROM AUTHOR]

A fine-grained (∼3.6 μm) Mg–6Al–3Sn (AT63) alloy prepared by a hot rolled method is subjected to uniaxial tensile tests within the temperature range of 25–250 °C. Mg 2 Sn and Mg 17 Al 12 precipitates at grain boundaries effectively retard the growth of dynamically recrystallized (DRXed) grains. Grain boundary sliding (GBS) is activated at 250 °C, which is indicated by the stable DRXed grain size and agglomeration of the precipitates at grain boundaries. Moreover, Mg 2 Sn and Mg 17 Al 12 precipitates promote the formation of dynamic recrystallization (DRX). Both the DRX and GBS result in the high elongation (151.4%) of the AT63 alloy at 250 °C. Results obtained here will shed some light on elevated temperature deformation mechanisms of a new type of Mg–Al–Sn system, which is critical to the development of new Mg alloys with potential for applications at elevated temperatures. [ABSTRACT FROM AUTHOR]

A improved and efficient procedure for the synthesis of pyrrolo[2,3,4- kl]acridin-1-one derivatives via the reaction of isatin and enaminone catalyzed by ceric ammonium nitrate under ultrasonic condition has been developed. Compared with the conventional methods, the remarkable advantages of this method are mild reaction conditions, operational simplicity, higher yield, and shorter reaction times. [ABSTRACT FROM AUTHOR]

Abstract: Mg–5Sn alloy are successfully fabricated by a horizontal centrifugal casting method. Developed columnar dendritic crystals under the gravity casting condition can be mostly transformed into fine equiaxed grains by the centrifugal casting. Compared with the gravity casting, compression strength, yield strength and elongation-to-failure are significantly improved by the centrifugal casting, which increase from 181.6 to 257.5MPa, 38.7 to 52.3MPa and 14.9% to 21.2% on position r 1 (centrifugal radius r 1=0.05m), respectively. Moreover, the centrifugal casting also enhances work-hardening ability of the alloy. The transformation of crystals results in the enhancement of the compression properties and work-hardening ability. The results obtained here will shed some light on special casting methods of Mg alloys, which is potential to develop new light alloys with high strength and elongation. [Copyright &y& Elsevier]

Abstract: A first-principles method was performed to calculate generalized stacking fault (GSF) energies in Mg alloys with Sn, Pb and Sn+Pb dopings for acting as references of designing Mg–Sn–Pb alloys. We clarify the effect of Sn is dominated than Pb atom on reduced unstable stacking fault energy ( ), especially in basal and pyramidal slip systems. Such a reduction of non-basal slip GSF energy is in favor of improving the ductility of Mg matrix. [Copyright &y& Elsevier]

Highlights: [•] As Al or Zn contents increase, GSF energies of Mg-Al-Zn solid solution decrease. [•] As Al or Zn contents increase, more locations with low GSF energy emerge. [•] Al and Zn dopings decrease GSF energy by softening Mg–Mg of slip planes. [•] Reduced GSF energy promotes activation of non-basal slip and enhances plasticity. [•] Criterion for predicting the most probable location for planar defect is proposed. [Copyright &y& Elsevier]

Additive manufactured (AM) technology as a novel fabrication method provides an unprecedented ability to completely design parts freely and breaks through the limitations of traditional approaches to manufacture complex structural parts. Meanwhile, magnesium (Mg) and its alloys as the lightest structural metal materials are among the most promising materials and always catch research attention. The combination of AM and Mg alloys would certainly provide new impetus for the practical application of Mg alloys. Although the research of AM-Mg alloys has made some progress and some AM-Mg alloys with impressive properties have been developed, there are still some intractable issues that hinder the further development and application of AM-Mg alloys. This paper provides a short review of the recent progress achieved in AM-Mg alloys, with a specific focus on selective laser melting (SLM), wire-arc additive manufacturing (WAAM), and solid-state AM technologies including additive friction stir (AFS) and friction stir additive manufacturing (FSAM). The defects, microstructure, and mechanical properties of AM-Mg products are summarized based on the type of AM technique. Besides, the effect of post-treatment on macro- and microstructures of SLM-Mg and WAAM-Mg alloys is also summarized. In addition, further perspectives and potential research directions are proposed for the development of AM-Mg alloys. This review could provide insights into the development of AM-Mg alloys with enhanced mechanical properties and promote the application of AM-Mg alloys. [ABSTRACT FROM AUTHOR]

Schmid factors (m) for typical slip modes (basal 〈a〉, prismatic 〈a〉, pyramidal 〈a〉 and 〈c + a〉 slips) and twinning patterns ( and twins) were systematically calculated in hexagonal close-packed Cd, Zn, Mg, Zr, Ti and Be. A monotonic effect on m-values was presented for pyramidal 〈a〉 and 〈c + a〉 slips, and and twinning patterns with decreasing c/a ratio. The results calculated herein were used to characterize deformation behaviors and provide essential data for anisotropic feature analysis. [ABSTRACT FROM AUTHOR]

Abstract: The plastic deformation behavior of as-cast Mg–3Sn–1Zn (TZ31) alloy was investigated at room temperature, which exhibits strong strain hardening ability (i.e. n=0.55 and H c=3.62) and high elongation (ε p=19.1%). The generalized stacking fault (GSF) energy of TZ31 alloy is reduced owing to dopings of Sn and Zn atoms, which is beneficial to improving activity of basal slip, activation of non-basal slips and formation of numerous deformation twins. The high density of twins significantly restricts dislocation motion, leading to strong strain hardening ability of the TZ31 alloy. Results obtained here will shed some light on deformation mechanisms of Mg–Sn–Zn alloys, critical to the development of new high-plastic magnesium alloys. [Copyright &y& Elsevier]

The reaction pathway of combustion synthesis (CS) of Ti5 Si3 in Cu- Ti- Si system was explored through a delicate microstructure and phase analysis on the resultant products during differential thermal analysis ( DTA). The formation of Cu- Si eutectic liquids plays a key role in the reaction pathway, which provides easy route for reactant transfer and accelerates the occurrence of complete reaction. Cu initially reacted with Si to form Cu3 Si by a solid-state diffusion reaction, which further reacted with Cu to form Cu- Si liquids at the eutectic point of ~802°C; then Ti was dissolved into the surrounding Cu- Si liquids and led to the formation of Cu- Ti- Si ternary liquids; finally, Ti5 Si3 was precipitated out of the saturated liquids by a solution-reaction-precipitation mechanism. The reaction pathway in CS of titanium silicide ( Ti5 Si3) could be described briefly as: Cu(s) + Ti(s) + Si(s)→ Cu3 Si(s) + Ti(s) + Si(s)→( Cu- Si)(l) + Ti(s)→( Cu- Ti- Si)(l)→ Cu(l) + Ti5 Si3(s). [ABSTRACT FROM AUTHOR]

The strain rate sensitivity (SRS) of a rolled Mg–3Al–3Sn (AT33) alloy increased with decreasing grain size at room temperature, owing to a change in the deformation mechanism from dislocation-dominated to twinning-mediated. Moreover, as deformation proceeds the SRS for slip-dominated grains (∼6μm) decreases gradually due to continuous activation of 〈c+a〉 slip, while that for twinning-mediated grains (∼41μm) decreases rapidly because of the combined action of 〈c+a〉 slip, contraction twinning and extension twinning . [Copyright &y& Elsevier]

Abstract: Dual-phase Li4Ti5O12–TiO2 nanocrystallines are prepared by a hydrothermal process and subsequent heat treatment. The as-prepared Li4Ti5O12–TiO2 nanocrystallines measure around 15–25nm in size and have abundant phase interfaces. Electrochemical measurements demonstrate that dual-phase Li4Ti5O12–TiO2 exhibit good electrochemical performance over individual single-phase Li4Ti5O12, especially at high current rates. Initial discharge capacities of dual-phase Li4Ti5O12–TiO2 nanocrystallines are 241 and 202mAhg−1 at discharge rates of 0.2 and 5C, respectively. Even after 50 cycles at 20C, the capacity still remains 140mAhg−1, which is four times greater than that of single-phase Li4Ti5O12 (29mAhg−1). The high electrochemical performance indicates that dual-phase Li4Ti5O12–TiO2 nanocrystallines are highly promising anode materials for lithium ion battery applications. [Copyright &y& Elsevier]

Abstract: Here, we report a facile approach for synthesizing nanocrystalline Li4Ti5O12 by microemulsion at ambient temperature following by annealing treatment at 600 °C for 2 h for the first time. The X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and nitrogen adsorption/desorption measurements are performed to characterize the structures and morphology of as-prepared sample. The as-prepared Li4Ti5O12 nanocrystalline around 30–50 nm in size and has high crystallinity, which displays excellent discharge/charge rate capability and cycling stability as anode materials for Li-ion batteries. More importantly, specific capacities for Li4Ti5O12 nanocrystalline achieved here are 173.7, 166.2, 136.2 and 130.2 mAhg−1 at 0.2, 1, 5 and 10 C after 50 cycles, respectively, indicating high potential application for Li-ion batteries. [Copyright &y& Elsevier]

Abstract: A small interfering RNA (siRNA) plasmid DNA (pYr-1.1-hU6-EGFP-siVEGF) was constructed and used for suppressing vascular endothelial growth factor (VEGF) expression and inhibiting tumor growth. Then, a (tyrosyl–seryl–leucine)–polyethyleneimine–poly(ethylene glycol) (YSL–PEI–PEG) conjugate was designed and synthesized as a gene carrier for the delivery of pYr-1.1-hU6-EGFP-siVEGF plasmid. The therapeutic peptide YSL was conjugated to PEI to improve the anti-cancer efficiency, and the PEG chain was introduced to reduce the serum protein adsorption and improve the stability of the complex in the systemic circulation. It was found that YSL–PEI–PEG could efficiently condense plasmid DNA when the vector/DNA weight ratio was higher than 2. Compared with PEI 25 kDa, YSL–PEI–PEG exhibited higher transfection efficiency and lower cytotoxicity. More importantly, the results showed that the gene delivery system owned strong ability to inhibit cancer cell proliferation in vitro and tumor growth in vivo. YSL–PEI–PEG has great potential as a gene vector for clinical applications. [Copyright &y& Elsevier]

Abstract: To evaluate the effect of different peptides as well as their introduction methods on target gene transfer of gene vectors based on disulfide-containing polyethyleneimine (SS-PEI), a series of peptides including N3-GRGDSF, GRGDSF, and EEEEEEEEGRGDSF (E8GRGDSF) were prepared. N3-GRGDSF was conjugated to SS-PEI by click chemistry and SS-PEI-GRGDSF was obtained. GRGDSF was non-covalently introduced into SS-PEI/DNA mainly through hydrogen bonding to obtain SS-PEI/DNA/GRGDSF complexes, whereas E8GRGDSF was further non-covalently introduced to SS-PEI/DNA through electrostatic force to obtain SS-PEI/DNA/E8GRGDSF complexes. Transfection efficiency of all complexes with peptides was lower than that of SS-PEI/DNA in COS-7 cells due to the fact that nonspecific endocytosis was prohibited after peptide introduction. Whereas in HeLa cells, transfection activity of SS-PEI-GRGDSF/DNA and SS-PEI/DNA/E8GRGDSF at certain w/w ratios was higher than that of SS-PEI/DNA. But the transfection efficiency of SS-PEI/DNA/E8GRGDSF at peptide/DNA w/w ratios higher than 30 dropped due to targeted binding interactions between surplus E8GRGDSF and the integrins in HeLa cells, which would prohibit specific endocytosis of E8GRGDSF in complexes. Transfection activity of SS-PEI/DNA/GRGDSF was lower than or comparable to that of SS-PEI/DNA because of loose complexes constructed by hydrogen bonding between GRGDSF and SS-PEI/DNA. [Copyright &y& Elsevier]

The Schmid factors for four slip systems (basal 〈a〉, prismatic 〈a〉, pyramidal 〈a〉 and 〈c + a〉 slips) and two twinning patterns ( and twins) were systematically calculated in magnesium as a function of angles between the c-axis and the loading direction. The results generated in this study can be effectively used to interpret deformation behaviors, including describing the flow stress and characterizing deformation behaviors, in magnesium and some hexagonal metals whose c/a axial ratios approximate to that of Mg (1.624). [ABSTRACT FROM AUTHOR]

Abstract: After combined additions of Sr and Sb, most primary Mg2Si crystals in Mg–3.5Si–1Al and Mg–5Si–1Al alloys transformed from equiaxed-dendritic shapes to octahedral morphologies; while eutectic phases also changed from Chinese script to short rod-shapes. The mechanisms of complex modification of Sr and Sb were attributed to the heterogeneous nucleation of primary Mg2Si on Sr11Sb10 nucleus, together with change in growth manners caused by incorporation of Sb in Mg2Si crystals. [Copyright &y& Elsevier]

Abstract: As-cast Mg–3Al–3Sn (AT33) alloy exhibits strong strain hardening ability, which is illustrated by the very high H c and n values. Decrease in generalized stacking fault (GSF) energies in AT33 alloys by Al and Sn additions facilitates the production of dislocations and activation of deformation twins, causing the accumulation of dislocations at twin boundaries, resulting in a high dislocation density in deformed alloys during tension deformation, which thereby mainly accounts for the strong strain hardening ability. [Copyright &y& Elsevier]

Abstract: The deformation mechanisms for rolled Mg–3Al–3Sn alloys were strongly dependent on grain sizes at room temperature. For grain sizes of ∼6–22μm, the deformation in tension was mainly dominated by dislocation-slip, which, however, turned to be mediated by deformation-twinning for those of ∼22–41μm. Moreover, as deformation proceeded, Hall–Petch slopes for slip-controlled-plasticity (k S) decreased gradually due to continuous activation of non-basal slips, while that for twinning-mediated-plasticity (k T) increased rapidly owing to increase in twin number and density, corresponding to grains below and above the medium-size of ∼22μm respectively. [Copyright &y& Elsevier]

Generalized stacking fault energies of magnesium without and with Al and Sn dopings were studied using first-principles calculations to investigate mechanisms of improved ductility for a new Mg–3Al–3Sn alloy. Reduced unstable stacking fault energy (γus ) results in the improved activity of and the activation of the and slip systems. Moreover, the lower γus of than of leads to the replacement of the latter by the former to be the second primary slip system. [ABSTRACT FROM AUTHOR]

Abstract: Cellular uptake and nuclear localization are two barriers to gene delivery. Here, we designed new gene delivery carriers with an N-terminal stearylated (STR) nuclear localization signal (NLS), PKKKRKV, present in the Simian Virus 40 large T antigen with the aim to overcome limitations, such as cell membrane and nuclear pores, offering attractive possibilities to enhance gene delivery. Four vectors with different structures of N-stearylated nuclear localization signal-octaarginine peptide (STR-PKKKRKV-R8 or STR-NLS-R8, STR-VKRKKKP-R8 or STR-reverse NLS-R8, PKKKRKV-R8 or NLS-R8, and VKRKKKP-R8 or reverse NLS-R8) were compared. The gene expression mediated by these vectors in dividing and non-dividing cells (both in 293T and HeLa cell lines) was investigated. The most efficient N/P ratio was 4 for STR-PKKKRKV-R8, STR-VKRKKKP-R8, and 0.25 for PKKKRKV-R8, VKRKKKP-R8. The maximum transfection activity of these vehicles (VKRKKKP-R8) was up to 80% as effective as jetPEI™ and the vehicles did not exhibit cytotoxicity. Interestingly, N-stearylated peptides presented lower transfection activity compared to peptides without N-stearylation at lower N/P ratios (0.25 to 1). Confocal study showed that the vectors could effectively promote the nuclear translocation. [Copyright &y& Elsevier]

Abstract: In this study, with the aim of designing an ideal anticancer drug carrier, we synthesized novel amphiphilic graft copolymers, P(Glu-alt-PEG)-graft-PCLA, based on poly(ethylene glycol) (PEG) segments and glutamic acid (Glu) units as the hydrophilic main chain, and poly(ɛ-caprolactone-co-lactide) (PCLA) as hydrophobic branches. The chemical structure of the copolymers was characterized by 1H MNR and FT-IR. The self-assembly of the copolymers to form micelles was studied by TEM, DLS and fluorescence spectroscopy. In vitro doxorubicin controlled release studies demonstrated that these graft copolymer micelles had high drug loading capacity and good controlled released properties, demonstrating their potential as a novel anticancer drug carrier. The drug loaded graft copolymer micelles exhibited efficient inhibition of HeLa cells in in vitro studies. [Copyright &y& Elsevier]

Four new polyoxometalate compounds consisting of Anderson-type anions and trivalent rare earth (RE) cations, [RE2(H2O)14M(OH)6Mo6O18][M(OH)6Mo6O18] · 14H2O, RE = Y, M = Cr(1), Al(2); RE = Yb, M = Al(3), Cr(4), have been synthesized in aqueous solution and characterized by elemental analyses, infrared (IR) spectra, thermal gravimetric (TG) analyses, and single crystal X-ray diffraction. [M(OH)6Mo6O18]3- as a bidentate ligand coordinates to two RE3+, forming a double-supported cation [RE2(H2O)14M(OH)6Mo6O18]3+. The cations and other [M(OH)6Mo6O18]3- anions in the crystals are linked via hydrogen bonding interactions tightly, forming four supramolecular compounds. The magnetic properties of 1, 3, and 4 have been examined by measuring their magnetic susceptibilities from 2 to 300 K. [ABSTRACT FROM AUTHOR]

Abstract: A surfactant-like tetra-tail amphiphilic peptide, [(C18)2K]2KR8GRGDS was designed and synthesized for targeted drug delivery. The resulting peptide–amphiphile, consisting of four hydrophobic aliphatic tails and a hydrophilic peptide head group, was able to self-assemble into nanosized micelles in aqueous medium at low concentration. Ibuprofen and doxorubicin (DOX) was loaded into peptide micelles as model hydrophobic drugs respectively, and the sustained release behavior was observed. Due to the incorporation of targeted arginine-glycine-aspartic acid (RGD) sequences and cell penetrating peptide (CPP) residue octaarginine (R8), the micelles could be recognized specifically by cancer cells, as well as transport through the cell membrane efficiently. The observation of laser-scanning confocal microscopy confirmed effective cellular uptaking of porphyrin-loaded peptide micelles. Furthermore, the porphyrin-loaded micelles exhibited low dark toxicity and high phototoxicity against cancer cells, indicating the powerful potential for effective photodynamic therapy. Combined with the low cytotoxicity of the peptide against both HeLa and 293T cell lines, the surfactant-like peptide developed in this study may be promising in clinical application for targeted drug delivery. [Copyright &y& Elsevier]

A series of amphiphilic diblock copolypeptides (ADCs), 5-(4-aminophenyl)-10,15,20-triphenyl-porphyrin (APP) conjugated poly( L-leucine)- block-polylysine (APP-LnKm) with different molar ratios of L-leucine unit and lysine unit were designed and synthesized. The optimized composition of the polypeptide was determined to be APP-L109K186, which has high fluorescence quantum yield and could self-assemble into micelles in an aqueous medium with mean particle size <30 nm. The in vitro study indicates that APP-L109K186 shows no significant dark cytotoxicity when the concentration is below 200 mg L−1 for HepG2 and HeLa cells. In contrast, the polymer exhibits apparent phototoxicity with low IC50 values toward HepG2 and HeLa cells, implying that the potential high photodynamic therapy efficacy of the polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 [ABSTRACT FROM AUTHOR]

Abstract: The present paper mainly studied the phase formation and reaction pathway of the Al–Ti–Si system in detail by thermal analysis combined with XRD and SEM observations. The phase formation sequence in Al–Ti–Si system from starting mixtures to final products with increasing temperature can be described as following: Al(l) + Ti(s) + Si(s) → (Al–Si)(l) + Ti(s) + Si(s) → Ti(Al,Si)3(s) + Si(s)Ti5(Si,Al)3 + Al(l). More importantly, the solubility of Si in Ti(Al,Si)3 decreased gradually while that of Al in Ti5(Si,Al)3 increased with temperature increasing, suggesting the transportation of Si atoms from intermediate aluminides Ti(Al,Si)3 to final stable silicides Ti5(Si,Al)3 and hence further confirming the formation of Ti5(Si,Al)3 at the expense of Ti(Al,Si)3. [Copyright &y& Elsevier]

Abstract: Effects of different oxygen transfer rates (OTR) on the cell growth and vitamin B12 biosynthesis of Pseudomonas denitrificans were first investigated under dissolved oxygen limiting conditions. The results demonstrated that high OTR accelerated cell growth and initial vitamin B12 biosynthesis rate, while lower OTR was critical for higher productivity in the late fermentation process. The oxygen uptake rates (OUR) corresponded well with OTR. Based on the metabolic intermediate analysis, a step-wise OUR control strategy was proposed. The strategy was successfully implemented in scale-up to an industrial fermenter (120,000l). A stable maximum vitamin B12 production of 208±2.5mg/l was achieved, which was increased by 17.3% compared with the control. Furthermore, the glucose consumption coefficient to vitamin B12 was 34.4% lower than that of the control. An efficient and economical fermentation process based on OUR criterion was established for industrial vitamin B12 fermentation by P. denitrificans. [Copyright &y& Elsevier]

Compared with the Ti–C system, the additions of metals (Fe, Al, and Cu) can increase the lattice parameter and stoichiometry of TiC x by forming metal–Ti intermediate phases (for C/Ti≤0.8). But for C/Ti>0.8, the Fe addition can decrease the lattice parameter and stoichiometry of TiC x by the formation of Fe–C solid solutions due to the hindrance of atom diffusion and the decrease of combustion temperature, while the additions of Al and Cu can increase them by the formation of Al–Ti and Cu–Ti solid solutions due to the dilution of Al and Cu. [ABSTRACT FROM AUTHOR]

Abstract: Pharmacophore models of Polo-like kinase-1 (PLK1) inhibitors have been established by using the HipHop and HypoGen algorithms implemented in the Catalyst software package. The best quantitative pharmacophore model, Hypo1, which has the highest correlation coefficient (0.9895), consists of one hydrogen bond acceptor, one hydrogen bond donor, one hydrophobic feature, and one hydrophobic aliphatic feature. Hypo1 was further validated by test set and cross validation method. Then Hypo1 was used as a 3D query to screen several databases including Specs, NCI, Maybridge, and Chinese Nature Product Database (CNPD). The hit compounds were subsequently subjected to filtering by Lipinski’s rule of five and docking study to refine the retrieved hits and as a result to reduce the rate of false positive. Finally, a total of 20 compounds were selected and have been shifted to in vitro and in vivo studies. As far as we know, this is the first report on the pharmacophore modeling even the first publicly reported virtual screening study of PLK1 inhibitors. [Copyright &y& Elsevier]

Abstract: The modification of Mg2Si in Mg–5Si alloys with KBF4 was investigated in detail. With the increase of KBF4 content, the alloys exhibited sub-modified and fully modified microstructures, but no over-modified microstructure was found. In the fully modified alloys, most of the primary Mg2Si particles exhibited the morphology of octahedrons. It is believed that B which came from the decomposition of KBF4 effectively confined the growth of primary Mg2Si to the octahedron morphology. [Copyright &y& Elsevier]

Abstract: Fabrication of steel-matrix composites locally reinforced with in situ TiC particulate using self-propagating high-temperature synthesis (SHS) reactions of 20wt.% Ni–Ti–C systems with ∼150μm, ∼38μm and ∼1μm C particles during casting has been investigated, respectively. The composites synthesized with ∼38μm or ∼1μm C particles consist of TiC and the alloy austenite containing Ni, while the one synthesized with ∼150μm C particle mainly consists of TiC, the alloy austenite containing Ni and an intermediate phase NiTi. With the increase of C particle size, the porosities of the composites significantly increase. Some large pores exist between the reinforcing region and matrix in the composites synthesized with ∼150μm and ∼38μm C particles, respectively, while no large pores are found between that in the composite synthesized with ∼1μm C particle. As C particle sizes decrease, the hardness and wear resistance of the composites increase. [Copyright &y& Elsevier]

Abstract: Steel matrix composites locally reinforced with different molar ratios of in situ TiC/TiB2 particulates (2:1, 1:1 and 1:2, respectively) have been fabricated successfully utilizing the self-propagating high-temperature synthesis (SHS) reactions of Ni–Ti–B4C and Ni–Ti–B4C–C systems during casting. Differential thermal analysis (DTA) and X-ray diffraction (XRD) results reveal that the exothermic reactions of the Ni–Ti–B4C and Ni–Ti–B4C–C systems proceed in such a way that Ni initially reacts with B4C and Ti to form Ni2B and Ti2Ni compounds, respectively, with heat evolution at 1037°C; Subsequently, the external heat and the evolved heat from these exothermic reactions promote the reactions forming TiC and TiB2 at 1133°C. In the composites reinforced with 1:2 molar ratio of TiC/TiB2, almost all TiB2 grains have clubbed structures, while TiC grains exhibit near-spherical morphologies. Furthermore, TiB2 grain sizes decrease, with the increase of TiC content. In particular, in the composites reinforced with 2:1 molar ratio of TiC/TiB2, it is difficult to find the clubbed TiB2 grains. Macro-pores and blowholes are absent in the local reinforcing region of the composites reinforced with 1:1 and 1:2 molar ratios of TiC/TiB2, while a few macro-pores can be observed in the composite reinforced with 2:1 molar ratio of TiC/TiB2. Moreover, the densities of the composites reinforced with 1:1 and 1:2 molar ratios of TiC/TiB2 are higher than that of the composite reinforced with 2:1 molar ratio of TiC/TiB2. The composite reinforced with 1:2 molar ratio of TiC/TiB2 has the highest hardness and the best wear resistance. [Copyright &y& Elsevier]

Abstract: The magnesium matrix composites reinforced with 2, 5 and 7.5 wt.% fine TiB2 (∼7 μm) particulates were fabricated by a novel two-step processing method, i.e. adding a TiB2–Al compact mixed with fine TiB2 and Al powders to magnesium melt and using a semi-solid slurry stirring technique. The microstructure and properties such as porosity, hardness and wear resistance of the composites were investigated. The distribution of fine TiB2 particulates is relatively homogeneous throughout the Mg matrix. As compared with as-cast AZ91, the hardness and wear resistance of the Mg composite was higher and increased with increasing of TiB2 content, but the porosity of the composites was relatively higher and increased with increasing of TiB2 content. [Copyright &y& Elsevier]

Background: Psychological resilience is important to mental health and professional development in newly graduated nursing students (NGNSs). However, the association between psychological resilience and mental health in NGNSs is less explored. Purpose: The current study was designed to determine mental health profiles measured by the Kessler 10 scale (K10) and evaluate the non-linear association between psychological resilience and mental health in NGNSs. Methods: A total of 472 NGNSs from the Be Resilient to Nursing Career program were assessed using the K10 and ten-item Connor–Davidson Resilience Scale (CD-RISC 10). Latent profile analysis and generalized additive model analysis were performed. Results: A four-class model based on the K10 was identified: lowest (28.0%), lower-middle (36.4%), upper-middle (26.1%), and highest (9.5%) subgroups. Academic degree and psychological resilience were significant indicators of mental health profiles. Psychological resilience was negatively and nonlinearly correlated with mental health when the CD-RISC 10 score was > 17. Conclusion: There exists heterogeneity in NGNSs' mental health. The negative and nonlinear association between psychological resilience and mental health can only be confirmed in NGNSs with moderate and high resilience levels. [ABSTRACT FROM AUTHOR]

The goal of this study was to improve the accuracy of model forecasting, such that forecasters could use model products to make more efficient daily weather predictions. Historical data of the 12 hr following a given time for various meteorological factors from the control forecasts of the European Centre for Medium‐Range Weather Forecasting (ECMWF) between 20 ° and 40 ° N latitude and 110 °–130 ° E longitude were used to verify the performance of the proposed method. Eight major meteorological factors were selected via correlation analysis between control forecast meteorological factors and real‐time rainfall. The samples were divided into four types using the K‐means clustered method. Each type was respectively modelled by long short‐term memory (LSTM) in order to correct rainfall forecasts for eastern China. The eight major meteorological factors were used as the model input, and the differences between real‐time rainfall data and model‐forecast rainfall were used as the model output. The corrected results revealed that the root mean square error decreased by 0.65, and the threat scores of light rainfall and rainstorms were improved. [ABSTRACT FROM AUTHOR]