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The effect of the grain boundary (GB) misorientation on plastic deformation of Inconel 718 (IN718) alloy was investigated in this paper, using in-situ tensile experiment at 650 °C in combination with crystal plasticity finite element method (CPFEM). The results indicate that dislocations tend to accumulate at GBs to form stress concentration, but the degree of stress concentration does not necessarily increase with the increase of the GB misorientation. It is attributed to the slip transfer at the GBs, determined by the angle between the slip systems of the two adjacent grains. There is a significant uncertainty in the slip transfer for GB misorientation larger than 10°. However, the m α β ′ SF α + SF β criterion, which is a function of the Luster and Morris m α β ′ combining the Schmid factors of the two slip systems with the GB misorientation, has some statistical separation significance. Slip transfer tends to appear at GB misorientation less than 30° and m α β ′ SF α + SF β > 0.78 . This study clarifies the mechanism of the influence of GB misorientation on IN718 microplastic deformation and provides a new strategy to study the deformation behavior of superalloys. [ABSTRACT FROM AUTHOR]

This study aimed to compare the dynamic microstructure evolution and the creep mechanical properties of second-generation nickel-based single-crystal superalloys at 780 °C/720 MPa and 850 °C/720 MPa. A method based on in situ scanning electron microscopy creep testing was used to identify the occurrence of slip bands. At the same time, the deformation mechanisms at 780 °C and 850 °C were discussed. The creep life at 780 °C was longer, almost five times that at 850 °C. Moreover, significant necking occurred in the primary creep at 780 °C, which controlled the entire creep process and accounted for almost 50% of the total life. In comparison, the primary creep at 850 °C was obviously shortened, mainly showing the characteristics of the second and third stages; the necking was mainly concentrated in the later stage of creep. This difference must be caused by the dislocation motion. The slip deformation mainly occurred at 780 °C, and the < 112 > dislocations shearing γ′ strengthening phase left obvious slip bands on the surface. The dislocations moved in the matrix channel in the early stage of creep at 850 °C, and the dislocations sheared γ′ strengthening phases in the later stage of creep while leaving obvious slip bands on the surface. [ABSTRACT FROM AUTHOR]

The effect of deformation temperature on tensile behavior of Inconel 718 alloy has been studied by a self-developed in-situ high-temperature tensile stage inside a scanning electron microscopy at a temperature range from room temperature (RT) to 750 °C. The dynamic microstructure evolution and mechanical properties at different temperatures were performed and compared by the uniaxial tensile tests. The in-situ test results showed that the mechanical properties and fracture mechanisms of Inconel 718 alloy were sensitive to deformation temperatures. From RT to 650 °C, the yield stress and ultimate tensile strength decrease slightly and the tensile ductility is comparable. While up to 750 °C, the yield stress and ultimate tensile strength decrease significantly, the elongation and reduction of cross section also showed a significant decrease from RT to 750 °C. It was found that at RT and 650 °C, tensile cracks tended to initiate around the carbide particles and the triple junctions of grain boundaries, also propagated transgranularly; at 750 °C, the cracks initiated at grain boundaries and propagated intergranularly. In fact, with the increase in deformation temperature, the fracture mechanism transformed from the ductile transgranular fracture to the brittle intergranular fracture. [ABSTRACT FROM AUTHOR]

High temperature materials usually serve under extreme conditions. In order to ensure the safety and reliability of industrial application, it is very significant to clarify the microstructural evolution and mechanical properties at high temperature. The in situ experiment combining mechanical tensile testing and heating in the scanning electron microscope (SEM) is a feasible method to study the relationship between the microstructure, mechanical properties, and temperature. However, it was challenging to acquire images of high quality when the temperature exceeded 800 °C due to the effect of thermal electrons and the instability of loading conditions at high temperature. In this study, a mini-tensile apparatus was devised and installed in an ordinary SEM, which can achieve a stable loading of 0–2200 N and obtain high quality images in the temperature range of 1150 °C. A highly efficient heat source with multi-layer thermal insulation was designed to prevent the other parts of the apparatus from being affected by high temperature. A symmetrical tensile structure was developed to ensure that the region of interest was always within the field of view of the microscope during testing. Thermal electrons were suppressed to ensure that the sample can be clearly distinguished at 1150 °C. In order to ensure the testing reliability, standard carbon steel was used to calibrate the instrument. Finally, a Ni-based single crystal superalloy, as an example, was tested using this in situ tensile testing system at 1150 °C to verify the main functions and reliability of the apparatus. [ABSTRACT FROM AUTHOR]

Abstract Laser direct melting deposited (LDMD) Ti-6Al-4V alloys are mainly used in aerospace fields. It is very important to study their deformation behavior as a function of the application conditions (i.e. temperature and stress). This work compared the dynamic microstructure evolution and mechanical properties of LDMD Ti-6Al-4V alloys at 23 ℃ and 650 ℃. A method based on in-situ scanning electron microscopy (SEM) tensile testing was used to identify the initiation of cracks and propagation mode of slip bands. The deformation mechanisms at low and elevated temperatures were discussed. The results showed that the strength decreased and the elongation increased with increasing temperature. These results were verified by the propagation modes of slip bands and opening of the active deformation systems. [ABSTRACT FROM AUTHOR]

This study compares the microstructure and tensile properties of Ti6Al4V components fabricated by laser direct metal deposition (LDMD) additive manufacturing (AM) in the transverse and longitudinal directions. The results show anisotropic tensile properties with the transverse direction having high tensile and fracture strengths and the longitudinal direction having a high elongation and reduction of cross section. The anisotropic mechanical properties are attributed to the anisotropic microstructural distribution. The transverse tensile specimen is composed of short columnar prior-β grains which grow perpendicular to the tensile direction, and have a lamellar structure. Along the β grain boundary, α GB and large α colonies were identified. However, the longitudinal specimen shows that the long β structure is parallel to the tensile axis and that the microstructure is composed of basket-woven α phases with shorter α plates and smaller colony sizes compared with those in the transverse specimen. The fracture mechanism induced by the anisotropic microstructure along the transverse and longitudinal directions was compared by examining the fracture process in real-time using uniaxial in-situ scanning electron microscopy (SEM) tensile testing. The results show that shear fracture, which is caused by the vertical β grain boundaries and large α colonies with long α plates, occurs in the transverse specimen. The shear mode is the main reason behind the enhanced tensile strength and fracture strength due to the high resistance to microcrack propagation. However, in the longitudinal specimens, symmetric necking behavior due to the fine α grains resulted in uniform deformation of the grains on both sides of the grain boundaries, inducing greater elongation. [ABSTRACT FROM AUTHOR]

• The process of dislocation slip across grain boundaries activating slip systems within adjacent grains of inconel 718 alloy during the tensile at 650 °C was observed using in-situ SEM technique. • A CPFEM model reflecting the microscopic morphology and lattice orientation of the alloy was developed and its reliability was verified. The evolution process of the slip systems of each grain were simulated using the model. • The slip transfer at general grain boundaries and annealed twin boundaries was investigated using a combination of slip traces analysis method and CPFEM. The influence of slip systems interactions on the slip transfer was analyzed in detail. • 113 results of adjacent grains slip transfer/blocking were counted, and a preliminary criterion for predicting slip transfer of inconel 718 alloy during plastic deformation at 650 °C was established. Adjacent grains slip transfer is an important mechanism for metal adaptation to incompatibilities in intergranular deformation. Thus, this paper investigates slip transmission at grain boundaries (GBs) and annealed twin boundaries (TBs) in Inconel 718 (IN718) alloy using in-situ tensile test at 650 °C by integrating slip trace analysis and the crystal plasticity finite element method (CPFEM). Results show that the m α β criterion, based on the match of intersection lines between slip planes to GB planes and slip directions, is more reasonable in predicting induced activated slip systems than Luster-Morris m α β ′ criterion. In addition, slip transfer tended to occur at m α β ′ > 0.83 and Δ b (1 / b) < 0.44 or m α β > 0.82 and Δ b (1 / b) < 0.46 for general GBs; when m α β ′ > 0.92 or m α β > 0.93 , continuous slip transfer is a crucial mechanism to coordinate strain and reduce stress concentration. Furthermore, the acceptable criteria for slip transfer at TBs are θ ≈ 0 and Δ b (1 / b) < 0.6 by experimental and computational results. This study deepens the understanding of the adjacent grains slip transfer behavior of IN718 and also provides a new strategy to study the deformation behavior of Nickel-based superalloys. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The promoting effect of pre-precipitated δ phase on deformation twinning and recrystallization behavior of Inconel 718 superalloy during hot compression was studied systematically. • The promoting effect on the formation of deformation twins was attributed to the lower stacking fault energy (SFE) and the local stress concentration. • A novel heteroepitaxial recrystallization (HERX) mechanism was found based on inverse precipitation. The delta (δ) processing strategy is an efficient heat treatment to refine and homogenize the grain microstructure of Inconel 718 superalloy (IN718). However, the microstructure becomes complicated by the effect of pre-precipitated δ phases, due to the coupling of precipitations, high temperature, and loading stress. The present study aims to clarify the effect of δ phases on the microstructure evolution of IN718, especially the promoting effect on deformation twins (DTs) and dynamic recrystallization (DRX) behavior. The results show that the promoting effect of δ phases on the formation of DTs was attributed to the lower stacking fault energy (SFE) caused by the precipitation of δ phases and the local stress concentration caused by the distribution of δ phases. The area fraction of DRX grains in the compressed δ-containing specimen was 21% higher than that in the compressed δ-free specimen, which was associated with the discontinuous dynamic recrystallization (DDRX) nucleation stimulated by the single δ phase and the continuous dynamic recrystallization (CDRX) nucleation promoted by the distribution of δ phases. Furthermore, a novel heteroepitaxial recrystallization (HERX) mechanism was found based on inverse precipitation from the undissolved δ phase to γ matrix phase grains with a crystallographic orientation relationship of (0_10)[1 0 2] δ //(__111)[0 1 1] HERX. [ABSTRACT FROM AUTHOR]

The effects of grain size on tensile behavior of Inconel718 superalloy have been characterized by an in-situ tensile stage inside a scanning electron microscopy (SEM) combined with electron backscatter diffraction (EBSD) and digital image correlation (DIC) at room temperature. The microstructure evolution and mechanical properties of specimens under different heat treatments were performed and compared. The in-situ tensile test showed that the yield strength, ultimate tensile strength and reduction of cross section decrease with the increasing grain size. An in-situ EBSD study showed that with increasing stress the local plastic deformation become more inhomogeneous. An analysis combined in-situ SEM morphology evolution, DIC strain distribution and EBSD results indicated that the grains deformed coordinately. Geometrically necessary dislocation (GND) density depends on the grain size and the orientation of individual grains. The coordinated deformation ability decreased with increasing grain size. The fracture morphology showed that with the increase of grain size, the fracture mechanism transformed from the ductile transgranular fracture to the brittle intergranular-transgranular mixed fracture. • The mechanical properties and morphology evolution of Inconel718 was investigated by in-situ SEM tensile technology. • The strain distribution evolution were determined combining with digital image correlation (DIC) technique. • The microstructure evolution were determined combining with EBSD technique. • The mechanisms of coordinated deformation and grain size effects were discussed. [ABSTRACT FROM AUTHOR]

The deformation behavior in polycrystalline Laser melting deposited (LMD) TA15 alloy was investigated at a temperature of 500°C using advanced in-situ Secondary electron microscopy (SEM) tensile setup coupled with Electron backscatter diffraction (EBSD). The grains morphology, crystal orientation, preferred pole texture, activated slip traces, grain boundaries evolution, and strain-induced misorientation were systematically analyzed during tensile straining. It was determined that the diverse α-grains (crystal orientation and morphology) revealed inhomogeneous deformation under tensile loading. The overall strain was allocated by grain rotation and substructure formation. The preferred oriented (0001) pole texture maximum was increased during initial strain level. In contrast, at higher strain, the texture intensity was decreased due to the formation and relocation of the newly formed substructures. The fraction of low angle grain boundaries (LAGBs 2–10°) was increased continually with increasing strain. Strain-induced dislocations within larger grains formed new LAGBs, and the increasing fraction of LAGBs was validated by Kernel average misorientation (KAM) map. The prismatic slip mode was identified as the primary active slip system at the initial deformation stage. The fraction of basal and pyramidal slips increased as the strain increased, describing the opposite trend to prismatic slip. The grains rotation and strain accumulation at the grain boundaries accommodated the plastic deformation, ultimately causing boundary sliding. • In-situ EBSD reveals real time microstructure evolution during tensile deformation. • Laser deposited TA15 demonstrate inhomogeneous deformation under tensile stress. • Basal slip system activates at higher SF values throughout the deformation process. • Large size grains endure subdivision under stress to accumulate the tensile strain. [ABSTRACT FROM AUTHOR]

This work studied the relationship between the fatigue behavior and microstructural evolution of a second-generation nickel-based single-crystal superalloy with [001], [102], and [314] orientations at room temperature. Strain-controlled low-cycle fatigue experiments were executed using an in-situ Scanning electron microscope (SEM) fatigue test system. Digital image correlation (DIC) mapping combined with SEM images were used to identify strain concentration and predict areas of crack initiation. Results showed that the deformation of specimens with different orientations was dominated by planar slip and followed Schmid law. Cross-slips were observed in the specimen with the [001] oriented orientation, while a single slip was observed for the other two orientations. Fatigue crack propagation was dominated by one slip system in the [001] and [314] oriented specimens. While in the [102] oriented specimen, it was alternately dominated by two slip systems. The fatigue life of Nickel-based single-crystal superalloys (NBSCs) had a high orientation dependence, and was related to the elastic modulus and crack propagation path. The cyclic softening that occurred during fatigue was caused by dislocation motion. • The fatigue behavior of three oriented nickel-base single-crystal superalloys was investigated by in-situ SEM technology. • The strain distribution, slip system, and the location of crack initiation were determined combining with DIC technique. • Effects of orientation and dislocation movements on fatigue behavior were discussed. [ABSTRACT FROM AUTHOR]

The plastic deformation behavior of three various orientation specimens of a nickel-based single-crystal (SX) superalloy were investigated by in-situ electron back-scattered diffraction (EBSD) at room temperature. Tensile properties, slip morphology, the evolution of Schmid factor, lattice rotation, and local strain were thoroughly discussed. In [1 1 13] specimen, the interaction of multi slip behavior induced local strain concentration, which restricted the plasticity but enhanced the strain hardening. Due to the single slip behavior, lower tensile strength and higher elongation were discovered in [9 1 7] and [2 1 3] specimens. Furthermore, during the plastic deformation of [1 1 13] specimen, lattice rotation is confined around [0 0 1] pole and shows a dispersive distribution, which is triggered by the multi slip behavior. A modified Sachs model considering multi slip behavior has been developed to predict the lattice rotation, this model is also applicable to severely deformed grains in polycrystalline materials. [ABSTRACT FROM AUTHOR]

In this paper, the deformation behavior of a nickel-based single-crystal superalloy with [ 1 ¯ 40] and [ 3 ¯ 40] orientations was studied at room temperature by in situ electron backscattered diffraction (EBSD) tensile equipment. The mechanical properties, slip behavior and the corresponding Schmidt factor were analyzed. The deformation bands generated during the plastic deformation stage were found and characterized by using the electron backscattered diffraction (EBSD) technique. Furthermore, the formation and propagation of deformation bands played a softening effect on stress–strain curves; however, the secondary slip bands occurring after the propagation of deformation bands played a hardening effect. Finally, the formation of deformation band and its propagation on the mechanical properties are discussed. [ABSTRACT FROM AUTHOR]

A high-temperature in-situ tensile stage setup developed by the authors was combined with electron backscatter diffraction (EBSD) to study the microstructural evolution behavior of Ti–6Al–4V alloy produced by laser direct melting deposition (LDMD) at 400 °C. This technique provided direct observation of the microstructure evolution and deformation behavior of materials under dynamic tensile loading at operating temperature. The evolution of grain morphology, misorientation angles of grain boundaries, and Schmid factor (SF) were systematically investigated. The results indicated that the grains no longer sustained the initial lamellar morphology and underwent a severe microstructural evolution during plastic deformation. Various grain morphologies were observed at different tensile strain levels. The statistical analysis revealed the reduction of high-angle grain boundaries' (HAGBs) fraction among α/α grains, with the opposite trend for low-angle grain boundaries (LAGBs). The increased Schmid factor values (SF > 0.4) were observed for prismatic (1–100) <11–20> and pyramidal (1–101) <11–20> slip systems, while those of the basal (0001) <11–20> slip system exhibited a sharp drop to SF > 0.4 at higher strain levels. Moreover, it was observed that high-SF grains changed their orientations, while low-SF ones split into smaller grains under tensile load. The kernel average misorientation (KAM) maps showed that deformation promoted dislocation motion, generating many LAGBs. The increasing number of LAGBs and slip openings reduced the boundary resistance and provided an easy path to detour the main crack propagation in response to the applied stress, while the LDMD Ti–6Al–4V specimen showed ductile fracture behavior. [Display omitted] • Microstructural evolution of LDMD Ti-6Al-4V alloy was investigated at 400 °C by in-situ EBSD. • Grain morphology and grain boundary characteristics were analyzed. • Plastic deformation behavior during continuous tensile process was studied. [ABSTRACT FROM AUTHOR]

Phenylalanine-58 is one of the conservative residues in the hydrophobic pocket of Cyt b5, which forms aromatic stacking with the heme b. Previous study showed that both the stacking and the property of the aromatic residue affect hydrophobicity of the heme pocket, leading to change of protein's property. In order to further reveal the essence we esterify the heme propionate of Cyt b5 F58Y and F58W, and eliminate the hydrogen bond between heme propionate and Ser64 in examining the effect of hydrogen net on the π-π interaction. In this paper thermal denaturation of DME-Cyt b5 and its F58Y and F58W mutants has been studied by UV-visible and CD spectra. The heme transfer reactions between these proteins and apo-myoglobin have been studied, as well. The results demonstrate that esterification did not destroy the aromatic stacking; however, it affects the stability of the proteins due to different volumes, hydrophobicities and hydrogen bonds forming ability of these substituents. [ABSTRACT FROM AUTHOR]

Studies the roles of Phe58 residue in stabilizing the structure of cytochrome b[sub 5]. Effects of π-stacking interactions between the side chain of aromatic amino acids; Detection of the porphyrin ring on structures and properties in cytochrome b[sub 5]; Mutation of the Phe58 residue to tyrosine and tryptophan through site-directed mutagenesis.

Nickel-based GH3536 alloy exhibits high strength but low ductility when produced by selective laser melting (SLM), which hinders its widespread application in aerospace. This paper employed a 'two-step' method of heat treatment to optimize the microstructure of the SLM GH3536 alloy and investigated the mechanical properties. Tensile tests were conducted on SLM GH3536 alloy before and after heat treatment at 750 °C, using an in-situ high-temperature tensile stage. The relationship between the microstructural evolution and deformation behavior of the alloys was investigated by combining the in-situ tensile experiments and crystal plasticity finite element method (CPFEM). The results suggested that the elongation can be increased by 80% without a significant reduction in tensile strength. The improved elongation is attributed to the complete recrystallization, formation of annealed twins and serrated grain boundaries after heat treatment. The study also investigated the deformation behavior and fracture mode of the alloy before and after heat treatment. Discussion was done on the influence of the microstructure, particularly the twin and serrated grain boundaries on the alloy's plastic deformation. This study enhanced the understanding of plastic deformation of SLM GH3536 alloy and provided a valuable reference for the design and post-treatment of superalloy. • A two-step heat treatment method is proposed to prepare GH3536 alloy with high ductility and acceptable strength. • High-temperature microplastic deformation and damage of GH3536 alloy were observed in-situ SEM technique and its influencing factors were analyzed. • The effects of twins and serrated grain boundaries on the properties were simulated using the CPFEM model. [ABSTRACT FROM AUTHOR]

Plastic deformation behavior of Inconel 740H superalloy during uniaxial tension at high temperature was investigated. The self-developed in-situ high-temperature tensile stage provides a better method for the study of tensile deformation of materials under different conditions. By a joint application of in-situ SEM and EBSD techniques, the tensile mechanical properties, microstructure, orientation, and grain boundary evolutions under near-service conditions (650 °C) were experimentally investigated. The results obtained show that due to the different grain orientations of polycrystalline metals, the grains with preferable orientation begin to slip first under the external force, while those orientation of harder grains will slip until they rotate to favorable orientation. In order to ensure the continuity of the matrix, the deformation between grains must be coordinated. Meanwhile, in-situ observation of the grain rotation at high temperature shows that rotation angles and paths of different grains are related to the initial orientation. By tracing typical grains and analyzing the grain rotation during in-situ EBSD testing, it was found that some grains with randomly distributed orientation at the initial state gradually changed to the direction between [001] and [111] poles with the stress increasing. This complies with the overall trend of a single grain rotation. However, after that the grains tend to reach the [101] pole rather than the stable orientation [112]. During the total deformation process, low-angle boundaries form and accumulate at the grain boundaries with concentration of stresses. While high-angle boundaries are slightly affected by the tensile deformation, and the density of twin boundary (TB) decreases. • Lattice rotation behavior at 650 ℃ was tracked using a self-developed SEM micro tensile stage and in-situ EBSD technique. • The rotation angle and path of different grains are related to the initial orientation. • Low angle boundaries occur and accumulate at the grain boundaries where stress is concentrated. • The incomplete of annealing twin is caused by the accumulation of dislocations near grain boundaries. [ABSTRACT FROM AUTHOR]

Titanium alloy was extensively used in aerospace industrial field. It has a great significance to directly reveal the deformation process as a function of application conditions. This work investigates the real-time deformation behavior of laser direct metal deposited (LDMD) Ti–6Al–4V alloy at 200 °C, using self-developed high temperature in-situ scanning electron microscope (SEM) tensile stage with a controlled heating system. The results showed that the microstructure of the sample comprised of columnar β grains with zigzag grain boundaries decorated by tilted α plates along the building direction. During uniaxial tensile, slip bands develop along the grain boundaries between α plates with increasing stress. Grain boundary sliding contributes to the high tensile elongation. Compared the mechanical properties along transvers tensile with those at room temperature, the tensile stress decreased and displacement increased at 200 °C. Therefore, higher elongation and reduction in cross-sectional area were identified at 200 °C than those at room temperature. The fracture of specimen at 200 °C shows obvious necking character and deep dimples with thin rims. Coalescence of slip bands at α/α interface creates voids and the coupling of voids nucleates micro-crack. α/α grain boundary interface constitutes path to the crack propagation. The high misorientation angle at columnar β grain boundary hinders the cracks propagation. Finally, the cracks accumulate along the columnar β grain boundary leading to fracture. • The microstructure deformation of LDMD Ti–6Al–4V alloy is studied by high temperature in-situ SEM tensile stage at 200 °C. • Slip bands development, cracks propagation, and columnar β GB hindering at 200 °C are investigated. • Temperature effect on the deformation mode and corresponding mechanical properties have been revealed. [ABSTRACT FROM AUTHOR]

Recent studies have shown that long noncoding RNAs (lncRNAs) are critical regulators in the central nervous system (CNS). However, their roles in the cerebellum are currently unclear. In this work, we identified the isoform 204 of lncRNA Gm2694 (designated as lncRNA-Promoting Methylation (lncRNA-PM)) is highly expressed in the cerebellum and derived from the antisense strand of the upstream region of Cerebellin-1 (Cbln1), a well-known critical cerebellar synaptic organizer. LncRNA-PM exhibits similar spatiotemporal expression pattern as Cbln1 in the postnatal mouse cerebellum and activates the transcription of Cbln1 through Pax6/Mll1-mediated H3K4me3. In mouse cerebellum, lncRNA-PM, Pax6/Mll1, and H3K4me3 are all associated with the regulatory regions of Cbln1. Knockdown of lncRNA-PM in cerebellum causes deficiencies in Cbln1 expression, cerebellar synaptic integrity, and motor function. Together, our work reveals an lncRNA-mediated transcriptional activation of Cbln1 through Pax6-Mll1-H3K4me3 and provides novel insights of the essential roles of lncRNA in the cerebellum. The long non-coding RNA lncRNA-PM activates transcription of the cerebellar synaptic organizer Cbln1 by promoting Pax6-Mll1-mediated H3K4me3 methylation, thereby helping to maintain cerebellar synaptic integrity and motor function. [ABSTRACT FROM AUTHOR]

Abstract: Crack propagation in sputter-deposited freestanding nanocrystalline tungsten films with a thickness of 38nm was studied using an in situ transmission electron microscopy (TEM) tensile technique. Distinct from coarse-grained tungsten, a totally intergranular fracture mode and toughening mechanisms were identified in the nanocrystalline tungsten. The transition of the fracture mode indicates that the plasticity is improved, and the improvement may be attributed to the effect of nano-size grains and the freestanding surface, which facilitate a high percentage of grain boundaries (GB) and a weak binding force. A theoretical model of the energy release rate and the deflection angle of cracks was established to quantitatively characterize the preferred deflection angle. The model predictions are in good agreement with the experimental findings. [Copyright &y& Elsevier]

Abstract: Wild-type phospholamban (WT-PLB) is a pentameric transmembrane protein that regulates the cardiac cycle (contraction and relaxation). From a physiological prospective, unphosphorylated WT-PLB inhibits sarcoplasmic reticulum ATPase activity; whereas, its phosphorylated form relieves the inhibition in a mechanism that is not completely understood. In this study, site-specifically 15N-Ala-11- and 15N-Leu-7-labeled WT-PLB and the corresponding phosphorylated forms (P-PLB) were incorporated into 1,2-dioleoyl-sn-glycero-3-phosphocholine/2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPC/DOPE) mechanically oriented lipid bilayers. The aligned 15N-labeled Ala-11 and Leu-7 WT-PLB samples show 15N resonance peaks at approximately 71ppm and 75ppm, respectively, while the corresponding phosphorylated forms P-PLB show 15N peaks at 92ppm and 99ppm, respectively. These 15N chemical shift changes upon phosphorylation are significant and in agreement with previous reports, which indicate that phosphorylation of WT-PLB at Ser-16 alters the structural properties of the cytoplasmic domain with respect to the lipid bilayers. [Copyright &y& Elsevier]

Li metal is the prospective candidate of next generation anode materials. However, the growth of dendritic Li during electrochemical cycling has severely hindered the practical application of rechargeable Li-metal batteries. Herein, "seaweed" graphene paper (SGP) is designed for 3D matrix of Li metal anode to address the growth of dendrites. SGP has abundantly exposed edges of graphene sheets and realizes ultrahigh density nucleation. Compared with nonuniform lithium deposition on parallelly stacked GP which has been observed by in-situ scanning electron microscopy, electrochemical deposition behavior of Li in SGP manifests as uniformly distributed granular lithium. Significant decrease of nucleation barrier can be observed during the dendrite-free deposition. With the elimination of dendritic Li growth and excellent stability of SGP host, the lithium anode based on SGP can run over 2500 cycles without short circuit and exhibits low voltage hysteresis. When matched with cathode LiCoO2, the full battery also presents stable cycling. There is no trace of lithium dendrite even after 1200 cycles which proves continuously regulating effect on lithium dendrites by SGP host. This work further develops potential application of graphene materials in the Li anode with high reversibility for stable cycling Li metal batteries. Ultrahigh density nucleation is realized by changing the stacked manner of graphene sheets. Compared with parallelly stacked graphene paper (GP), "seaweed" stacked GP (SGP) has more exposed edges which can supply abundant nucleation sites. As the host, SGP eliminates the growth of dendritic Li during cycling and assembled Li@SGP symmetrical batteries can stably plating/stripping for over 2500 cycles at 1.0 mA cm−2. [Display omitted] • Nonuniform lithium deposition on parallelly stacked GP was observed by in-situ SEM. • Ultrahigh density nucleation realized by "seaweed" GP with abundant exposed edges leads to dendrite-free deposition. • Corresponding batteries present extraordinary long-cycle dendrite-free performance. [ABSTRACT FROM AUTHOR]

Characterizes some surface negatively charged residue mutants of bovine liver cytochrome b... (cyt b...). Expression and purification of the cyt b... membrane-bound hemoprotein; Use of electrospray mass spectrometry to measure the molecular weight of mutant proteins; Global structure of the mutant proteins.

Tumour-derived exosomes (TDEs) play an important role in tumourigenesis and progression by regulating components in the tumour microenvironment (TME), however, the role of TDE-related immune genes in hepatocellular carcinoma is not fully known. We systematically analysed TDE genes from ExoCarta and immune genes from Immport,Machine learning ultimately identified eight TDE-related prognostic immune genes and used them as the basis for constructing a risk model, which was constructed to better predict patients with hepatocellular carcinoma (HCC) compared with published prognostic models. There were significant differences between the high and low risk groups in terms of biological functioning. Low-risk group were more sensitive to immunotherapy, the sensitivity to oxaliplatin and cisplatin differed between the high- and low-risk groups, and knockout of the core gene RAC1 limited the malignant biological behaviour of hepatocellular carcinoma cells. In conclusion, TIRGs are effective in predicting the prognosis of patients with hepatocellular carcinoma and provide a new perspective on immunotherapy and chemotherapy for patients. [Display omitted] • TDEs-related prognostic immune genes are closely associated with hepatocellular carcinoma prognosis and immune infiltration. • TDEs-related prognostic immune genes can better identify the prognostic status of hepatocellular carcinoma patients. • The low-risk group was sensitive to oxaliplatin and the high-risk group was sensitive to cisplatin. • Low-risk group is more sensitive to immunotherapy. • Knockdown of the core gene RAC1 limits the malignant behaviour of hepatocellular carcinoma cells. [ABSTRACT FROM AUTHOR]

Spinel Co 3 O 4 , as conversion-type transitional metal oxide, has attracted extensive interest for LIBs anode due to its high theoretical capacity. The application of transitional metal oxide including Co 3 O 4 anode has been proved challenging due to voltage hysteresis, bad rate capability, extremely low initial Coulombic efficiency (typically 65∼70%), and volume change induced mechanical failure. Among the facing problems, the fundamental understanding of severe capacity fading at high C-rate is clearly needed to be unveiled. In this paper, we utilized in situ transmission electron microscopy (TEM) to study the electrochemical reaction process of spinel Co 3 O 4 anode and firstly unveiled the rate-dependent morphological and structural evolution process. It has been demonstrated that the structural evolution from pristine Co 3 O 4 phase to the formation of Co/Li 2 O composites during lithiation (bias = −3 V). Impressively, the Co/Li 2 O composites could fully delithiated into pure tightly-contacted CoO crystals (∼1.45 nm) at lower delithiated bias (+3 V); while the lithiated products partially transformed into the CoO crystals, and further suffered a severe aggregation (∼6 nm) at higher delithiated bias (+8 V). These findings advance the understanding of the mechanism of capacity fading at high current density (C-rate) in conversion-type spinel Co 3 O 4 anode for lithium ion batteries. [ABSTRACT FROM AUTHOR]

• A new strategy is developed to modify the nickel foam. • The selection of coating materials is developed. • Coating Li 3 PO 4 on surface of nickel foam enhances the uniformity of deposition. Herein, two coating amorphous Al 2 O 3 and Li 3 PO 4 with different properties were firstly demonstrated for Li/Nickel Foam (Li/NF) composite anode via atomic layer deposition (ALD) method to form a free-standing Li host material for dendrite-free Li anode. Impedance test shows that Li nucleates easily on Li 3 PO 4 surface compared with NF and Al 2 O 3 surface. Significantly, scanning electron microscope (SEM) observation of tracing the same site shows that a large number of lithium dendrites were deposited on NF and Al 2 O 3 surface, while no dendrite growth was observed on Li 3 PO 4 surface. The test of cells shows that Li@Li 3 PO 4 @NF anode presents better cycling stability and rate capability. Li 3 PO 4 reduces the nucleation overpotential and the surface energy barrier, which can increase the overall surface lithiophilic, so that the entire surface is deposited uniformly. This work promotes the uniform deposition of lithium and sheds light on the development of ultrastable lithium metal anode. [ABSTRACT FROM AUTHOR]

The pseudocapacitive materials, like spinel NiCo 2 O 4 (NCO), that use Faradaic reactions to store charge have been widespread paid attention for supercapacitors application. So, it is a basic fundamental guideline that the preparation of higher-performance pseudocapacitive materials depends on achieving and accelerating more Faradaic reactions in the aspect of electrodes. In this work, based on the mentioned principle, we report a facile method that could significantly promote the capacity of NiCo 2 O 4 nanoelectrode through annealing precursor nanowires (NWs) in different volume ratios of N 2 and O 2 condition. The pristine NCO (V N2 : V O2  = 0:1) only exhibited inferior performance with a specific capacitance of 0.88 F cm −2 (338.5 F g -1  at 2 mA cm −2 ) and capacitive retention of 54% from 2 to 30 mA cm −2 . While, for a comparison, the highest comprehensive performance of NCO-9 (V N2 :V O2  = 9:1) electrodes delivered superior specific capacitance of 3.8 F cm −2 (1461 F g -1  at 2 mA cm −2 ), excellent rate retention of 77% and good cycling stability. These boosted pseudocapacitive properties both in capacity and rate capability are attributed to the severe oxygen vacancy defects introduced in nitrided NCO NWs. The involving richness-enabled oxygen defects significantly enhance the electron/ions transportation, and then efficiently alter the well-known capacitive surfacial reaction into bulk pattern in the charge-discharge cycles. This dramatically increased electron/ions kinetics and electrochemical cites for Faradaic reactions. These results provide a deep insight into correlating oxygen vacancies induced structural and chemical evolution on enhanced capacitive performances of redox-active-NiCo 2 O 4 materials. [ABSTRACT FROM AUTHOR]

Reduced activation ferritic martensitic (RAFM) steel is chosen as a structural material for test blanket modules (TBMs) to be constructed in International Thermonuclear Experimental Reactor (ITER) and China Fusion Engineering Test Reactor (CFETR). Chinese specific RAFM steel named with CLF-1 has been developed for CFETR. In this paper, a narrow-gap groove laser multi-pass welding of CLF-1 steel with thickness of 35 mm is conduced by YLS-15000 fiber laser. Further, the microstructures of different regions in the weld joint were characterized, and tensile impact and micro-hardness tests were carried out for evaluating the mecharical properties. The results show that the butt weld joint of CLF-1 steel with a thickness of 35 mm was well-formed using the optimal narrow-gap laser filler wire welding and no obvious defects was found such as incomplete fusion cracks and pores. The microstructures of backing layer is dominated by lath martensites and the Heat-Affected Zone (HAZ) was mainly filled with two-phase hybrid structures of secondary-tempering sorbites and martensites. The filler layer is similar to the backing layer in microstructures. In tensile tests, the tensile samples from different parts of the joint all fractured at base metal (BM). The micro-hardness of weld metal (WM) was found to be higher than that of BM and the Heat-Affected Zone (HAZ) exhibited no obvious softening. After post weld heat treatment (PWHT), it can be observed that the fusion zone of the autogenous welding bead and the upper filling beads mainly consist of lath martensites which caused the lower impact absorbing energy. The HAZ mainly included two-phase hybrid structures of secondary-tempering sorbites and martensites and exhibited favorable impact toughness. [ABSTRACT FROM AUTHOR]

In this report, using atomic layer deposition (ALD) technique, TiO 2 layer with different thickness is conformally deposited on the surface of MoO 3 nanobelts for enhanced-performance anode. Impressively, the MoO 3 @85-TiO 2 (85 cycles coating) nanobelts anode shows its best comprehensive value: The initial Coulombic efficiency (CE) dramatically increases from 44% to 73% compared to bare MoO 3 electrode; It also delivers highest initial specific capacity of 1153.7 mAh g −1 at 100 mA g −1 , which is superior to the uncoated MoO 3 (427.3 mAh g −1 ). Additionally, MoO 3 @85-TiO 2 nanobelts show a remarkable long-life stability from initial 913.6 to 935.8 mAh g −1 after 400 charge-discharge cycles at 400 mA g −1 . The advanced TEM characterizations reveal that the TiO 2 layer can experience a transition from amorphous into crystalline Li 2 Ti 2 O 4 with cubic structure (a = 8.375 Å) during cycling, which are acted as an efficient lithium ion conductor. Furthermore, the quantified mechanical properties demonstrate a remarkable decrease in the bending elastic modulus of MoO 3 @85-TiO 2 nanobelts compared to that of pristine MoO 3 . Therefore, the boosted electrochemical performance can be attributed to efficient lithium ions transportation across the moderate conductor layer and robust mechanical integrity that the large volume variation. These results advance the understanding in the coating regulated materials for enhanced-performance LIBs. [ABSTRACT FROM AUTHOR]

Amorphous Al 2 O 3 coating was prepared on Ni-based single crystal superalloy via atomic layer deposition (ALD) for high temperature oxidation protection. The oxygen inward transport and outward-cation diffusion were hindered by amorphous Al 2 O 3 coating, and the coated alloy showed high oxidation resistance. The low oxygen partial pressure at the alloy/coating interface altered the alloy oxidation behavior, allowing the priority oxidation of protective Al and Cr elements. The oxidation process was controlled by the growth of Cr 2 O 3 and Al 2 O 3. The coating exhibited high spallation resistance. Degradation of the coating, the formation of NiAl 2 O 4 phase in amorphous Al 2 O 3 layer, was observed. • Amorphous Al 2 O 3 coating was proposed and prepared on Ni-based single crystal superalloy. • The amorphous Al 2 O 3 coating improved oxidation resistance and exhibited high adhesion. • The amorphous Al 2 O 3 coating altered the oxidation behavior of the alloy. • The effect mechanism of amorphous Al 2 O 3 coating on the alloy oxidation was discussed. [ABSTRACT FROM AUTHOR]

A tensile technique was developed and coupled with in-situ transmission electron microscopy observations to directly characterize the crack propagation mechanism in sputter-deposited, ultra-thin, freestanding nanocrystalline Ag thin films with a thickness of 60 nm. The developed technique directly revealed the fracture mechanism; the thin film with nanoscale grains exhibits ductile fracture behavior, and the crack propagates through void nucleation, growth, and coalescence ahead of the crack tip. A model for the energy release rate during the propagation of nanovoids was established to quantitatively characterize the equilibrium length of the voids. Based on experimental measurements and theoretical calculations, the effects of stress distribution and energy transformation on the nucleation position, equilibrium length, and growth rate of the nanovoids are discussed. [ABSTRACT FROM AUTHOR]

Eimeria acervulina was isolated from chicken at Hebei province, China. The gene of merozoite surface antigen 3-1E was amplified and cloned into pET28a(+) vector and then transformed into Escherichia coli BL21 strain. Results showed that 3-1E fusion protein band of about 22 kDa was identified by SDS-PAGE. Western blot analysis indicated that the recombinant protein specifically reacted with E. acervulina polyclonal antibody. [ABSTRACT FROM AUTHOR]

Tooth enamel is formed in an extracellular environment. Amelogenin, the major component in the protein matrix of tooth enamel during the developing stage, could assemble into high molecular weight structures, regulating enamel formation. However, the molecular structure of amelogenin protein assembly at the functional state is still elusive. In this work, we found that amelogenin is able to induce calcium phosphate minerals into hydroxyapatite (HAP) structure in vitro at pH 6.0. Assessed using X-ray diffraction (XRD) and 31P solid-state NMR (SSNMR) evidence, the formed HAP mimics natural enamel closely. The structure of amelogenin protein assembly coexisting with the HAP was also studied using atomic force microscopy (AFM), transmission electron microscopy (TEM) and XRD, indicating the β-amyloid structure of the protein. SSNMR was proven to be an important tool in detecting both the rigid and dynamic components of the protein assembly in the sample, and the core sequence 18EVLTPLKWYQSI29 was identified as the major segment contributing to the β-sheet secondary structure. Our research suggests an amyloid structure may be an important factor in controlling HAP formation at the right pH conditions with the help of other structural components in the protein assembly. [ABSTRACT FROM AUTHOR]