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In recent years, the concept of hybrid manufacturing has been proposed to heal the defects in additive manufactured (AM) materials, taking advantage of both the AM technique and additional secondary processes such as hot forging. However, the healing mechanism of defects, as well as the relationship between defects elimination and microstructure evolution need to be further studied. In this work, we designed laser-powder bed fusion (L-PBF) Ti6Al4V samples with high initial porosity, making it easier to trace the pores during the quasi in-situ X-ray tomography (XRT) observation. The samples were conducted hot forging by Gleeble-3800 system, which is named as electro-assisted micro-forging (EAMF) treatment, considering the characteristic of this process is to directly electrify the specimen to generate Joule heat. The results show that the porosity was effectively reduced by combining effects of electric current, heat energy and compressive stress during EAMF. Simultaneous enhancement of strength and ductility was realized. The defect-healing mechanism that comprising various stages was comprehensively disclosed. The competitive relationship between defect-healing and microstructure coarsening was revealed, which has a guiding effect on the subsequent optimization of process parameters. [Display omitted] • An electro-assisted micro-forging (EAMF) treatment induces significant defect-healing effect. • Simultaneous enhancement of strength and ductility was achieved. • The defect-healing mechanism comprising three stages was disclosed. • A competitive relationship between defect-healing and microstructure coarsening was revealed. • Interrupted In-situ XRT and FIB-TEM were used. [ABSTRACT FROM AUTHOR]

Aims: Biological techniques can manage plant diseases safely and in environmentally friendly ways, but their efficacy needs improvement. It is of the utmost importance to search for powerful microbes for the effective control of plant diseases. Methods and Results: Unheated self‐digestive solutions (SDS) that were heated at 100°C for 30 min(H‐SDS) or stored for 12 months at room temperature (S‐SDS) were prepared from Lysobacter enzymogenes LE16 broth culture to study their potential as biocontrol agents. This bacterium produced protease, phosphatase, lysozyme and siderophores in pure culture as well as 12 secondary metabolites including novel antibiotics lysobactin, WAP‐8294A2 and mupirocin determined based on the antiSMASH 5.0.0 blast database. A poison plate assay revealed the antagonistic activities of SDS, H‐SDS and S‐SDS against an animal pathogenic bacterium Staphylococcus aureus, a phytopathogenic bacterium Pseudomonas syringae pv. tabaci, and numerous plant pathogenic fungi and oomycetes, including Colletotrichum gloeosporioides, Penicillium italicum, Alternaria alternate, Rhizoctonia solani, Didymella bryoniae, Sclerotinia sclerotiorum, Phytophthora nicotianae and Phytophthora capsici. The greenhouse experiment showed that SDS was highly effective in controlling pepper blight disease, which is caused by P. capsici. Compared with only pathogen inoculation, the application of SDS to the soil in preventive or curative treatments significantly reduced the disease incidence and index with relatively high control efficacy of 86·2–93·1%. Conclusions: SDS enriched lytic enzymes, siderophores and antibiotics, has a wide antimicrobial spectrum, and shows potential as a new, safe and effective biocontrol agent against plant diseases. Significance and Impact of the Study: Autolysates of the new biocontrol bacterium L. enzymogenes LE16 demonstrated the potential for industrial production and commercial use as a promising biocontrol agent in agriculture. [ABSTRACT FROM AUTHOR]

The present study aims at elucidating the impact of unavoidable defects in selective laser melting (SLM) additive manufactured alloys on fatigue performances. The novel idea is to reveal the relationship between the printing defect and fatigue crack growth, by intentionally embedding a 500 μm spherical defect in an SLM-Ti6Al4V alloy exerted to low-cycle fatigue (LCF). The results show that the cyclic softening of the specimen was not affected by the embedded defect and surprisingly its fatigue life was nearly the same as the virgin specimens free of embedded defects at low strain amplitudes. The performance is attributed to the single crack initiation site and only small change in the stress intensity factor range (Δ K). In contrast, when subjected to higher strain amplitudes during LCF, the embedded defect dominates the crack initiation and crack propagation occurs readily. It is shown that the experiments support a model description based on the competitive failure mechanisms between the surface defects and internal defects. [ABSTRACT FROM AUTHOR]

A method for a significant improvement of the self-healing efficiency of Cr 2 AlC ceramic via pre-oxidation is presented. Micro-notches were made with the focused ion beam technique on specimens with a pre-existing oxides scale followed by an oxidation healing treatment. An interesting finding is that in the former case the notches are more effectively healed by producing a dense Al 2 O 3 layer than the counterpart specimens without a pre-existing scale. An explanation for this phenomenon is provided based transmission electron microscopy revealing a transition layer between Cr 2 AlC and Al 2 O 3 with a gradient distribution of chemical composition. [ABSTRACT FROM AUTHOR]

Mechanisms for the rapid hardening induced by electropulsing treatment (EPT) in an AISI 4340 steel were investigated by X-ray-diffraction analysis, transmission electron microscopy observations and Vickers microhardness tests. It is found that the combined strengthening effects induced by solid-solution atoms, dislocations, and nano-twins gradually surpass the dispersion strengthening after EPT. Besides, carbides dissolution and phase transformation were also detected due to the decreasing trend of Gibbs free energy during EPT. Such rapid hardening method may be preferential for manufacturing metallic materials for its time-saving and energy conservation. [ABSTRACT FROM AUTHOR]

The effects of electropulsing treatment (EPT) and annealing on the tensile behaviors of twinning-induced plasticity (TWIP) steel after interrupted tension are compared. It is found that EPT effectively restores the tensile property of specimens with macro voids completely, while annealing could not. The selective heating and thermal compressive stress induced by EPT around voids make them readily to be healed while keeping the matrix unchanged. The healing effect of voids improves the strain-hardening capability of TWIP steels and leads to the recovery of strength and elongation of the EPT specimen, relative to those annealed counterparts. [ABSTRACT FROM AUTHOR]

The effects of electropulsing treatment (EPT) on the microstructure and corresponding mechanical properties of a nano-lamellar 316L austenitic stainless steel were investigated. The original 316L stainless steel features a nano-lamellar framework with high density of dislocations via cold rolling. The nanostructured stainless steel was hardened and strengthened after EPT with relatively low discharge voltage, which may result from the cooperative effect of stable nano-lamellar structure and mobile dislocations recovery. Both the microhardness and tensile strength would decrease significantly with the increase of discharge voltage due to the nucleation and growth of recrystallized grains in the steel. [ABSTRACT FROM AUTHOR]

Microstructural evolutions of a cold-rolled CoCrFeMnNi high-entropy alloy (HEA) induced by electropulsing treatment at room temperature (RT-EPT) and liquid nitrogen temperature (LN-EPT) were investigated and compared. Finer recrystallized grains were obtained by LN-EPT compared to RT-EPT with the same discharge voltages. The recrystallization mechanisms were discussed based on the electropulsing induced athermal and thermal effects. The former mainly contributes to promoting the nucleation of grains, while the latter mainly affects the new grain growth. Meanwhile, the precipitation of the Cr-rich phase was greatly suppressed due to the electropulsing which is contrary to the annealing samples. The LN-EPT sample being treated with discharging voltage of 6 kV exhibited the highest yield strength (846 MPa) among the EPT samples due to the partially recrystallized heterogeneous microstructure. As a consequence, LN-EPT may be developed as a promising method to fabricate desired microstructure and mechanical properties. • A novel cryogenic electropulsing method (LN-EPT) was applied on high-entropy alloy. • Partially and fully recrystallized microstructure was realized via LN-EPT. • Cr-rich second phases were inhibited via EPT compared with traditional annealing treatment. • LN-EPT samples show relative superior mechanical properties compared with the RT-EPT samples. [ABSTRACT FROM AUTHOR]

Precipitation strengthening is one of the significant strengthening mechanisms for metallic alloys owing to its excellent strengthening effect. Here, we effectively introduce homogenous nanosized precipitates into a Mg–6Zn–4Al–1Sn-0.5Mn (wt.%) alloy via extrusion and double aging to enhance strength-ductility synergy. The yield strength, ultimate tensile strength, and total elongation of the Mg alloy are 303.1 ± 15.8 MPa, 392.5 ± 3.9 MPa, and 21.1 ± 2.4%, respectively. Using transmission electron microscopy and atomic level high angle annual dark field-scanning TEM, in addition to the icosahedral quasicrystalline (IQC) particles at the grain boundary, we find that there are two kinds of nanoprecipitates in the matrix. The majority of nanoprecipitates are cuboid IQC phases with nanodomains parallel to the basal plane of the Mg matrix, while the minority of nanoprecipitates are rod-like β 1 ′ phases containing IQC clusters vertical to the basal plane. These homogenous nanoscale precipitates and grain refinement contribute 50.5% and 30.2% of the yield strength. This work sheds new light on understanding the nanoscale IQC precipitate strengthening mechanisms of magnesium alloys and provides a novel method to fabricate alloys with superior mechanical properties. [ABSTRACT FROM AUTHOR]

The friction and wear properties of a contact strip in a contact strip rubbing against a contact wire were studied. A series of experimental tests on the vibration between the contact strip and contact wire were conducted on a high-speed block-on-ring tester under the conditions of electric current of 0 A and 250 A, sliding speed of 200–350 km/h and normal loads of 120 N. Scanning electron microscopy (SEM) was used to observe morphology of the worn surfaces. Experimental results indicate that the vibration of the contact strip is aggravated with increasing sliding speed. In contrast with those without electric current, the friction coefficient of the strip against the contact wire decreases and the wear rate increases obviously with increasing sliding speed. With the increase of the sliding speed, the contact surface temperature between the strip and contact wire with electric current grows faster. The arc discharge becomes stronger and stronger with the sliding speed, which results in aggravated arc erosion wear on the surface of the strip. Delamination wear and arc erosion wear are two main wear mechanisms for the strip against contact wire with electric current of 250 A when the sliding speed is bigger than 250 km/h. [ABSTRACT FROM AUTHOR]

The aim of selective laser melting (SLM) technology is to obtain high quality workpieces through optimization of processing parameters. However, the defects and microstructures are simultaneously changed with the change of process parameters, so their effects are hard to discuss separately. To meet this challenge, 24 combinations of laser power and scanning speed were designed to fabricate the SLM manufactured Ti6Al4V alloy, and the volumetric energy density (VED) of them ranges from 30 J/mm3 to 100 J/mm3. It is found that with the increase of VED the prior β boundary tended to be straighter and wider, while the morphology of α lamella did no change distinctively. The porosity varies from nearly 0% to 4% in this process zone, which has significant effects on the tensile properties. For samples with high porosity (0.25%–4%), the influence of defects covered the influence of microstructure, leading to stochastic ultimate tensile strength and stably low elongation. For samples with low porosity (0.01%–0.25%) and extra-low porosity (<0.01%), the stably high ultimate tensile strength revealed the slight difference between microstructures. The poor productivity of elongation for samples with low and extra-low porosity was also discussed. [ABSTRACT FROM AUTHOR]

Outward growth of oxide scale on Cr2AlC surface during multiple annealing at 1100°C was investigated with ex situ microscopy. A dense alumina scale was formed on the surface of Cr2AlC samples after annealing for 40h. A wedge-shaped specimen with varying thickness of oxide scale was prepared by focused ion beam slicing for further annealing. It is concluded that the outward diffusion of Al ions via grain boundaries dominates the growth of oxide scale during repeated annealing. This result is relevant to the self-healing kinetics of exposed cracks in MAX phase ceramics via cyclic heating. [ABSTRACT FROM AUTHOR]

Abstract: A series of tests on arc discharge were carried out to better understand the wear mechanism of a contact strip rubbing against a contact wire with electrical current. The arc discharge process was recorded with a high-speed camera. The arc voltage drop and electric current were measured throughout the test. The accumulated arc discharge energy was evaluated. Experimental results show that the wear rate of the contact strip is approximately directly proportional to the accumulated arc discharge energy in logarithmic coordinates. Increasing the normal force can suppress arc discharge and decrease wear of the contact strip. [Copyright &y& Elsevier]

Abstract: Y2.9Ce0.1Al5O12 (YAG:Ce3+) phosphors with 80±5nm are successfully prepared by hydrothermal processing followed by the post annealing process in Ar/15%H2 atmosphere. The emission intensity of the as-prepared YAG:Ce3+ nano-phosphor is as high as with that of the ∼15μm YAG:Ce3+ commercial phosphor. Meanwhile, the YAG:Ce3+ nano-phosphors prepared in both Ar/15%H2 and air atmosphere show same stable emission intensity under continuous irradiation of blue excitation light, although this photobleaching behavior is easily observed for YAG:Ce3+ nano-phosphors in the literatures. Photobleaching is probably suppressed by complete crystallinity due to the post annealing process and solid morphology due to the hydrothermal process in the present work. [Copyright &y& Elsevier]

Abstract: In situ microcantilever bending tests were carried out to evaluate the healing efficiency of pre-notched Ti2AlC ceramic after annealing at 1200°C for 1.5h. Microcantilevers of different orientations were fabricated with focused ion beam method at different locations, i.e. in a singular Ti2AlC grain, at a grain boundary or at the Ti2AlC–Al2O3 interface after healing. Ti2AlC microcantilever shows an anisotropic bending strength (ranging between 9.6GPa and 4.6GPa depending on the precise crystallographic orientations) that is closely related to the different atomic bonds in the layered structure. After healing, the Ti2AlC–Al2O3 microcantilevers exhibit almost the same strength of about 5.2GPa, i.e. slightly higher than the cleavage strength (4.6GPa) of the initial Ti2AlC microcantilevers. It suggests that the orientation of the matrix grain has no significant influence on the strength of healed microcantilevers. Furthermore, it turns out that the strength of the microcantilever with a healed grain boundary is at least twice the strength of the initial Ti2AlC cantilever with a grain boundary. It is concluded that the oxidation dominated self-healing mechanism of Ti2AlC ceramics can result in a perfect recovery of mechanical performance. The paper shows that the in situ microcantilever bending test provides a quantitative method for the evaluation of the strength of self-healing ceramics. [Copyright &y& Elsevier]

Abstract: A 2×4 factorial experiment was conducted to determine the effect of aflatoxin B1 (AFB1) at dose rates of 0, 320, 640, 960ng/ml on ruminal fermentation of substrates high in alfalfa hay (HA, alfalfa hay: maize meal=4:1) and ryegrass hay (HR, ryegrass hay: maize meal=4:1). In vitro dry matter disappearance was not affected by AFB1 dosage. The asymptotic gas production numerically declined by increase in AFB1 dosage for HA and HR. AFB1 dosage decreased gas production rate (P<0.05), and the rate for HR was lower for HA (P<0.05). Ammonia N concentration declined with the increase in AFB1 dosage for HA (P<0.05), and was higher for HA than HR (P<0.01). The highest AFB1 dosage decreased total VFA concentration by 12.7% for HA and 9.6% for HR (P<0.05), compared with that of the zero dosage. The molar proportions of propionate and butyrate did not differ between HA and HR, but molar proportions of isobutyrate, valerate and isovalerate were distinctly greater in HA than in HR (P<0.01). After 72h incubation, 0.831 (HA) and 0.842 (HR) of included AFB1 (960ng/ml) was degraded. The results implicate that rumen microbes have high ability to degrade AFB1. [Copyright &y& Elsevier]

Abstract: Mulberry leaves of 14 cultivars of Morus atropurpurea Roxb (MAR), 7 cultivars of Morus alba Linn (MAL) and 8 cultivars of Morus multicaulis Perr (MMP) were assessed for their differences in chemical composition and in situ ruminal degradation. The contents of acid detergent fibre (P=0.073) and ether extract (P<0.0001) ranked as: MMP>MAL>MAR. Crude protein (CP), neutral detergent fibre and polyphenolic contents of the leaves did not differ between three species. Nylon bags containing the leaves were incubated for 2, 6, 12, 24, 36, 48 and 72h in three rumen cannulated dairy cows. Soluble CP fraction and fractional degradation rate did not differ between three species, but the potential degradable CP fraction in the leaves was greater for MAR than the others (P=0.005). Effective CP degradability was consistently ranked: MAR>MAL>MMP (P=0.051). Non-tannin phenols and total tannins were negatively correlated with the soluble CP fraction (r=−0.48, P<0.01) and the potential degradable CP fraction (r=−0.36, P<0.05), respectively. In summary, the mulberry leaves with high protein, low fibre and tannin contents could be exceptional forage for use in ruminant animals. [Copyright &y& Elsevier]

Abstract: Hungate''s method is a well-accepted protocol for the isolation or incubation of anaerobes with a roll tube technique. The aim of this study was to stimulate fungal enzyme production by optimizing the components of Hungate''s medium for the growth of a rumen fungus Anaeromyces sp. YQ3. The organism was grown on corn stalks and incubated for 10 days in defined media with two glucose levels (G+, glucose in the Hungate''s medium as a glucose control; G−, glucose removed in a modified Hungate''s medium) and four N sources (N1: yeast extract+tryptone+(NH4)2SO4 in Hungate''s medium (control); N2: yeast extract+(NH4)2SO4; N3: tryptone+(NH4)2SO4; and N4: tryptone+yeast extract). In the G− media, the recovered activities of feruloyl esterase (FAE) (P<0.0001), acetyl esterase (AE) (P=0.0065) and xylanase (P<0.0001) were decreased, while the G+ media with N1 nitrogen stimulated the production of FAE and xylanase (P<0.0001). The G− medium with N2 nitrogen increased the recovered activities of carboxymethyl cellulase (P=0.0001) and avicelase (P<0.0001), while the N3 and N4 media increased the recovered activity of AE (P=0.0015). The N4 medium was comparable to the N1 medium in stimulating the amount of recovered xylanase activity. The activities of FAE (P<0.0001), AE (P<0.0001), and xylanase (P<0.0001) showed a time-dependent increase and reached their peaks at day 10, while the avicelase activity peaked at day 8 (P=0.0071). The esterase activities (FAE and AE) were positively correlated with the enzyme activities of xylanase and carboxymethyl cellulase (r >0.48, P<0.05). After a 10-day incubation, the glucose in the Hungate''s media contributed to an increase in organic matter disappearance (P<0.0001) and volatile fatty acid (VFA) concentration (P<0.0001), except for molar acetate proportions. The N4 treatment increased organic matter disappearance and total VFA concentration (P=0.0002). The change in N source did not alter molar proportions of acetate, propionate and valerate, while the N2 treatment increased molar butyrate proportion (P<0.0035), and both N2 and N3 increased the molar proportion of branched chain VFAs (P<0.0041). In summary, the glucose in the Hungate''s medium is beneficial for stimulating the production of esterases and xylanase, thereby promoting fungal growth. Amending the N source in Hungate''s medium brings about different yields of rumen fungal esterases and polysaccharide hydrolases that have important nutritional impacts on fibre degradation in ruminant animals. [Copyright &y& Elsevier]

Among various low-angle tracking methods, the three-dimensional beamspace domain maximum likelihood (3-D BDML) estimation proposed by Zoltowski is a computationally attractive and optimal method that can be processed in the reduced beamspace domain. However, the estimation performance of 3-D BDML deteriorates in the presence of interference or an additional target, especially at low altitudes, because the dimension of the signal and noise exceeds the dimension provided by the three beams. This study proposes a new low-angle tracking method for two objects in a 3-D beamspace domain using a linearly constrained adaptive array. The increased signal dimension owing to the interference or the additional target is reduced in the beamspace domain by using the beamforming weight that is designed to remove the largest principal component in the covariance matrix. Numerical simulation results are provided to show the estimation performance of the proposed method. [ABSTRACT FROM AUTHOR]

Abstract: A 10-day pure culture of Neocallimastix sp. YAK11, isolated from rumen fluids of yak (Bos grunniens) was evaluated for fibrolytic activity, apparent dry matter disappearance (ADMD), ferulic acid, reducing sugars and volatile fatty acids (VFA). The fungus was grown on oat straw (OS), corn stalks (CS), rice straw (RS) and wheat straw (WS). Recovered activity of ferulic acid esterase peaked at day 5 in all roughages, and the lowest activity was found with low fibre OS throughout the incubation (P<0.0001). The recovered activity of acetyl esterase peaked at day 6 with WS and RS and at day 7 with CS and OS (P<0.0001). The highest acetyl esterase activity was found with high fibre WS throughout the incubation (P<0.0001). Xylanase activity increased with all roughages and was maintained at a high level throughout the incubation (P=0.0102). The lowest xylanase activity was found in WS (P<0.0001), but cultures grown on OS, CS and RS showed no differences. The highest ADMD and reducing sugar values occurred in OS and the lowest in WS (P<0.0001). Ferulic acid release did not differ between four roughages. ADMD was positively correlated with xylanase activity (r =0.51, P<0.01). Total VFA concentration was greatest in OS (P<0.0001) and highly correlated with fibrolytic enzyme activities (r >0.42, P<0.01). Molar proportions of acetate and valerate did not differ in the roughages. The lowest propionate and branch chained VFA levels occurred in WS (P=0.0115), and the highest butyrate levels occurred in OS throughout the 10-d incubation (P=0.0464). The highest ratio of non-glucogenic to glucogenic acids (NGR) occurred in WS (P=0.0481). NGR peaked for all roughages around day 3 and then slightly declined for the rest of the experiment. In general, the isolate was capable of a pronounced degradation that would depend on the fibre content of the roughages. Screening of fungi from rumen fluids of yak would appear to be a useful strategy to obtain highly active esterases and polysaccharide hydrolases. [Copyright &y& Elsevier]

Abstract: During the reflowing procedure, the Cu concentration in the solder affects the coarsening mechanisms of intermetallic compound (IMC) grains. For the Sn3Cu solder, the mean radius of the IMC grains was proportional to the cube root of the reflowing time; while it follows the square root relation with the reflowing time for the SnAgCu and Sn solders. It is proposed that the flux from the substrate was only consumed to coarsen the IMC grains for Sn3Cu solder, while it was separated into two fluxes for the SnAgCu and Sn solders at the reflowing initial procedure. For the Sn3.8Ag0.7Cu/Cu and Sn/Cu couples, the size distribution of the IMC grains well agrees with the modified flux driven ripening (FDR) model when the value of r/〈r〉 is above 1; while it would closely match with Marqusee and Ross analysis when the value of r/〈r〉 is below 1. For Sn3Cu/Cu couple, the size distribution of IMC grains shows good agreement with the FDR model. However, for SnPb/poly-Cu, during the solid-state aging procedure, the mean radius of the IMC grains was proportional to the cube root of the aging time. And the size distribution of IMC grains is well consistent with the FDR model. [Copyright &y& Elsevier]

Abstract: Fermentation characteristics of 5 combinations of fenugreek (Trigonella foenum-graecum L., FH) and alfalfa (Medicago sativa L., AH) hay in ratios (FH:AH) ranging from 100:0 to 0:100 were studied in response to inocula of either rumen fluids (RF) or rumen fluids plus a fungal culture of Neocallimastix sp. YAK11 (RFF). For the RFF treatment, the forage combinations were anaerobically incubated with fungal culture and Menke''s medium for the first 24h and then incubated with the stratified rumen fluids for 72h. The value of the in vitro dry matter disappearance did not differ between RF and RFF. Cumulative gas production (ml/g DM) was fitted to an exponential model: GP t =GPmax×(1− e −c×time); the maximum gas production (GPmax) was lower in RFF than in RF (P<0.01), but the rate constant c showed no difference. Molar proportions of CO2, CH4, and H2 were similar in both treatments. The pH values were lower for RFF than RF (P<0.01). Concentrations of ammonia N and total volatile fatty acids (VFA) did not differ between RF and RFF. In VFA pattern, molar proportions of propionate and valerate did not differ between RF and RFF. Molar proportion of acetate was greater in RFF than in RF (P<0.05), while molar butyrate and branch-chained volatile fatty acids proportions were lower in RFF than RF (P<0.01). Fibrolytic activities of carboxymethyl cellulase, avicelase, ferulic acid esterase, and acetyl esterase were similar between RF and RFF, but xylanase activity was greater in RFF than in RF (P<0.01). Regardless of the ratios of FH to AH in the forage combinations, the fungal inoculation at the inclusion level used did not alter the in vitro digestibility, but increased the molar acetate proportion and decreased the molar proportions of butyrate, branch-chained volatile fatty acids and maximum gas production. [Copyright &y& Elsevier]

The microstructure of oxide scales formed on Ti2AlC surface after oxidation at 1200°C is investigated. The results reveal an inhomogeneous morphology of the oxide scales, i.e. islands of coarse rutile grains pile up on fine-grained Al2O3 layer. Local cross-sectional observations show that the rutile islands grow on top of cavities in the parent material. A model is proposed to describe the resulting microstructure after oxidation. These results are relevant in optimizing the self-healing conditions of Ti2AlC at high temperature. [ABSTRACT FROM AUTHOR]

Abstract: By means of equal channel angular pressing (ECAP) technique, an Mg–12Gd–3Y–0.5Zr alloy was processed at 300°C for one and four passes. A bi-ultrafine (BU) microstructure of Mg-alloy, consisting of matrix grains and the second-phase particles with sizes smaller than 1μm, was obtained after the fourth pass of ECAP. The formation of this BU microstructure originated from the complex interactions between the matrix grains and second-phase particles during the ECAP processing at elevated temperature. A simultaneous improvement of both strength and ductility was achieved in the sample with the BU microstructure, compared with the original sample. The increase in strength is resulted from the refinement of both matrix grains and second-phase particles, while the improved ductility is attributed to the considerable plasticity provided by both dislocation mechanism and profuse shear bands in the BU microstructure. An enhanced plasticity induced by the shear-band mechanism is proposed for the magnesium alloy with the BU microstructure. [Copyright &y& Elsevier]

A growth trial was conducted to estimate the optimum requirement of dietary available phosphorus (P) for Chinese sucker juveniles. Triplicate groups of juveniles Chinese sucker (initial mean weight: 1.77 ± 0.02 g, mean ± SD) were fed diets containing graded levels (3.1, 5.3, 7.5, 9.6 and 11.8 g kg) of available phosphorus. The basal diet (diet 1), containing 3.1 g kg available P, was supplemented with graded levels of monocalcium phosphate to formulate four experimental diets. The fish were fed twice daily (08:00 and 17:00 h) to satiation for 8 weeks. During the experimental period, the water temperature fluctuated from 27.5 to 30.5 °C and dissolved oxygen was more than 6 mg L. The specific growth rate, protein efficiency ratio were all significantly increased by dietary available phosphorus up to 7.5 g kg ( P < 0.05) and then levelled off beyond this level. Feed conversion ratio significantly decreased with dietary available phosphorus level up to 7.5 g kg ( P < 0.05). Dietary treatments did not significantly affect feed intake ( P > 0.05). Efficiency of phosphorus (P) utilization significantly decreased with dietary available phosphorus level ( P < 0.05). Body composition analysis showed that the whole-body lipid, ash, calcium, phosphorus, magnesium (Mg), zinc (Zn) and copper (Cu) contents were all significantly affected by dietary available P concentration ( P < 0.05); however, no significance were found for manganese (Mn) concentration and calcium/phosphorus (Ca/P) ratios in whole-body among all the treatments ( P > 0.05). Dietary phosphorus levels also significantly affected the mineralization of vertebrae and scale ( P < 0.05), and Ca/P ratios in scale were not influenced by dietary P supplementation, while vertebrae Ca/P ratio decreased with dietary available P levels ( P < 0.05) (quadratic effect, P < 0.001). Signs of phosphorus deficiency were characterized by poor growth, slightly reduced mineralization and an increase in body lipid content. The blood chemistry analysis showed that dietary available P had distinct effects on enzyme activities of alkaline phosphatase, as well as contents of triacyglycerol and total cholesterol ( P < 0.05). Broken-line analysis based on weight gain indicated the minimum available phosphorus requirement for the optimal growth of juvenile Chinese sucker was 7.4 g kg. Based on the phosphorus content in whole body, vertebrae or scale indicated that the requirements were 8.3, 8.8 and 8.6 g kg respectively. [ABSTRACT FROM AUTHOR]

Abstract: Sixteen combinations of 5 treatments at 4 levels were designed in a L16(45) orthogonal experimental design to evaluate associative effects of five methanogenesis inhibitors at four dose levels: nitroethane (NE, 0mM, 5mM, 10mM and 15mM), 2-nitroethanol (NEOH, 0mM, 5mM, 10mM and 15mM), 2-nitro-1-propanol (NPOH, 0mM, 5mM, 10mM and 15mM), pyromellitic diimide (PMDI, 0mM, 0.02mM, 0.05mM and 0.07mM) and 2-bromoethanesulphonate (BES, 0mM, 0.01mM, 0.03mM and 0.05mM) on in vitro ruminal methane production of the mixed substrate (Chinese wildrye hay:maize meal=4:1) using a cumulative gas production technique. After 48h incubation, in vitro dry matter disappearance (IVDMD), total gas production (GP48, ml/g DM) and total volatile fatty acids (VFA) production in various combinations of these inhibitors were decreased by 10.6–56.0, 26.5–44.5 and 20.3–47.6%, respectively (P<0.05). The molar proportion of acetate in the inhibitor combination groups was decreased by 6.6–12.5% while those of propionate and butyrate were increased by 7.0–19.2 and 21.9–56.5% (P<0.01), respectively. Methane proportion (MP) in total gas production was reduced by 79.4–98.5% (P<0.01), and the highest inhibition occurred in the combination of 10mM NE, 10mM NPOH, 0.07mM PMDI and 0.01mM BES in cultures. The partial correlation coefficients between NE, NEOH, NPOH, PMDI or BES and CH4 proportion were −0.465 (P<0.01), −0.417 (P<0.01), −0.355 (P<0.05), −0.408 (P<0.01) and −0.345 (P<0.05), respectively, indicating that NE was the most potent inhibitor, followed by NEOH and PMDI, and finally NPOH and BES. In general, VFA production in the inhibitor combinations was substantially shifted to produce much more butyrate and propionate and less acetate. The combination of 15mM NE, 10mM NEOH, 5mM NPOH, 0.07mM PMDI and 0.01mM BES in cultures, leading to >95% methane inhibition, may be the optimal application of these inhibitors with less depression of total VFA production. Further feeding trials to validate these combinations is still required on rumen function, methane production, growth performance and milk production. [Copyright &y& Elsevier]

Abstract: A comparison of caecal fermentation patterns of neutral detergent fibre prepared from alfalfa hay (aNDF) with glucose (GLU), cellobiose (CEB) and microcrystalline cellulose (MCC) was conducted with an in vitro batch culture. Caecal contents, freshly collected from adult rabbits, were taken as inoculum. After a 72-h incubation at 39°C, the highest mean activities of xylanase, acetyl and feruloyl esterases occurred in aNDF (P<0.05) while highest carboxymethyl cellulase activity occurred in GLU (P<0.05). Both GLU and CEB were rapidly fermented and characterized by much lower pH (P<0.01) and greater production of total volatile fatty acids (VFA). The lowest concentration of total VFA occurred in aNDF and MCC (P<0.05). The fermentation of aNDF and MCC resulted in higher molar proportions of propionate, valerate, branched chain VFAs than those of GLU and CEB (P<0.05); the molar proportions of acetate ranked as: GLU>MCC>CEB>aNDF (P<0.01); the molar proportion of butyrate ranked as: CEB>aNDF>GLU>MCC (P<0.01). The total gas production of GLU and CEB were greater than those of MCC and aNDF (P<0.05). Molar CH4 proportion ranked as: MCC>aNDF>CEB>GLU (P<0.01), and the molar H2 proportion in MCC was greater than those in other substrates (P<0.01). These results suggest that fermentation of MCC and aNDF produce more glucogenic acids, especially propionate. Low hydrogen recoveries for all substrates implicated that mechanisms of H2 disposal other than methanogenesis, such as reductive acetogenesis, may exist in the caecum and depend upon the nature of the carbohydrate. [ABSTRACT FROM AUTHOR]

Abstract: Fibrolytic activity distributions of 18 enzyme products, mostly obtained in China, were examined in terms of protein concentration and fibrolytic activities on model substrates. The hydrolytic capacities were determined by an in vitro ruminal degradation assessment and the enzymatic release of reducing sugars or ferulic acid from neutral detergent fibre fractions of corn stalks (NDFcs). Most enzyme products were characterized by xylanase, carboxymethyl cellulase (CMCase) and β-glucanase (EG), which had the potential to improve in vitro dry matter disappearance of NDFcs after a 16-h enzymatic pre-treatment followed by a 24-h ruminal degradation using a batch culture method (P<0.05). Quadratic effects of xylanase, CMCase, EG and ferulic acid esterase (FAE) occurred on the release of reducing sugars or ferulic acid from NDFcs (P<0.05). The effective fibrolytic activity combinations required to reach the highest release of reducing sugars were 418–1385U xylanase, 111–567U CMCase, 347–376U EG and 2.0U FAE per g NDFcs substrate. The addition of an enzyme product with a dominant FAE activity did not alter the total volatile fatty acid production at a low dose level of 1.0mg/g or 4140U/g substrate of corn stalks after a 48-h in vitro batch culture. However, a lower ratio of non-glucogenic to glucogenic acids occurred in the fermentation of corn stalks with inclusion of the FAE dominated enzyme product (P<0.05). These results suggest that all enzyme products in China were characterized or blended with enzyme extracts with xylanase, CMCase and EG. The rational combination of enzyme products necessary to reach a specific FAE activity with a specific fibrous forage, together with xylanase, CMCase and EG activities, should be considered in the design of a compound enzyme product for enhancing the cell wall degradation of fibrous crop residues, based on scientific understanding of the mode of enzymatic actions in the rumen. [Copyright &y& Elsevier]

Abstract: With an increase in the use of advanced high strength steels in vehicle architectures, materials joining issues (e.g., performance and manufacturability) have become increasingly important. Among the various joining methods, adhesive bonding is increasingly used in automobile manufacturing. Successful implementation of adhesive bonding for vehicle welding application requires not only the knowledge of issues related to processing and design but also a practical method to repair the bonded joints. In this study, a plug stud welding (PSW) process is proposed to repair the bonded steels. The process is as follows: (a) punching a hole at the first metal sheet; (b) inserting slug into hole; (c) and (d) passing electrical arc through slug of sufficient intensity to promote melting at the interface between the first and second metal sheets and slug, thereby (e) securing the metal workpiece. The repaired bonded DP780 steel samples were fabricated and tested. Test results were compared with that of conventional resistance spot welds. The results show that repaired bonded steels had comparable tensile and fatigue strengths to conventional spot welds. These results suggest that plug stud welding process is feasible for repairing the adhesive-bonded steels in vehicle assembly plants and collision body shops. [Copyright &y& Elsevier]

Abstract: Neocallimastix sp. YQ1 and Anaeromyces sp. YQ3 were isolated from rumen fluids of Holstein steers using a modification of the roll-tube technique of . After a 9-day incubation for YQ1, and a 4-day incubation for YQ3, with optimal carbon and N supply in cultures, crude enzyme solutions of both fungi were prepared by centrifuging cultures for 10min at 1000× g at 4°C. Enzymological characteristics of ferulic acid esterase and acetyl esterase were measured in the crude enzyme solution. The Michaelis constants (K m ) and maximum velocities (V max ) of ferulic acid esterase against methyl ferulate at pH 6.0 and 39°C were 30μM and 8.05mU for YQ1 and 129μM and 3.15mU for YQ3, respectively. With substrate of p-nitrophenyl acetate, the K m and V max of AE at pH 6.0 and 39°C were 0.21mM and 336mU for YQ1 and 5.26mM and 854mU for YQ3. Enzymatic release of reducing sugar, ferulic acid, and p-coumaric acid from complex fibre-rich feedstuffs was evaluated, and YQ3 released more reducing sugars from wheat straw, but less from the other plant materials especially maize bran and corn stalks. YQ3 liberated much more hydroxycinnamic acids from corn stalks, and YQ1 liberated much more hydroxycinnamic acids from maize bran. Anaerobic rumen fungi showed species diversity of enzymological characteristics of ferulic acid esterase and acetyl ester esterase, and exhibited a strong capability to release ferulic acid and p-coumaric acid from complex fibre-rich feedstuffs. Therefore anaerobic fungi, especially their FAE, should not be neglected in studies on biodegradation of plant cell walls in the rumen as well as on industrial processes developed to release ferulic acid and p-coumaric acid from agricultural by-products with potential commercial industrial applications, such as precursors of natural vanillin, natural antioxidants, food preservative agents, anti-inflammatory agents and photoprotectants. [Copyright &y& Elsevier]

Abstract: To obtain an optimal feruloyl and acetyl esterase production of an anaerobic Neocallimastix sp. YQ2 grown on either Chinese wildrye grass hay (CW) or alfalfa hay (AH) or corn stalk (CS), three simultaneous 2×4 factorial experiments of 10-day pure cultures were applied with two levels of glucose (G+: glucose added at a level of 1.0g/L and G−: without glucose) and four levels of N source (N1: 1.0g/L yeast extract, 1.0g/L tryptone and 0.5g/L (NH4)2SO4; N2: 2.8g/L yeast extract and 0.5g/L (NH4)2SO4; N3: 1.6g/L tryptone and 0.5g/L (NH4)2SO4; N4: 1.4g/L yeast extract, 1.7g/L tryptone). Optimal combinations of glucose and N supplements for YQ2 to produce ferulic acid esterase, acetyl esterase, xylanase, carboxymethyl cellulase and avicelase were G+N2 for CS, G−N3 for CW, G−N3 for CW, G+N2 for CS, and G+N2 for CW, respectively. These five kinds of fibrolytic enzyme had different variation tendencies and maximum activity at different times of incubation. The fungus produced more total volatile fatty acids, and less propionic acids and iso-valeric acids, when CS was used as growth substrate, as well as more acetic acids when CW was used than when AH was used (P<0.05). As for the enzymological characteristics of feruloyl and acetyl esterase, Michaelis constants (K m) and maximum velocities (V max) of ferulic acid esterase against methyl ferulate at pH 6.0 and 39°C were 90μM and 1.15mU, and the Michaelis constants and maximum velocities of acetyl esterase at pH 7.0 and 39°C were 2.97mM and 294mU with specific substrate of p-nitrophenyl acetate. The crude enzyme preparation of the fungi grown on CS with the G+N1 combination had higher potential to release ferulic acid, and p-coumaric acid in CS up to 129.8g/kg the alkali-extractable ferulic acid and 88.1g/kg the alkali-extractable p-coumaric acid, respectively (P<0.05). The strong capability to hydrolyse plant materials by the fungus can be used to understand the degradation of fibre-rich feedstuffs in the rumen and also open prospects for development of direct fed feed enzyme products for ruminants. [Copyright &y& Elsevier]

Abstract: The aim of this study was to compare different methods to determine ferulic acid esterase (FAE) activity in commercial enzyme products and to measure the FAE activity in the rumen of steers fed different diets (A: 5kg forage and 4kg concentrate; B: 5kg forage and 5kg concentrate; C: 5kg forage and 6kg concentrate). FAE activities in seven commercial enzyme products were determined by high performance liquid chromatography (HPLC) at a wavelength of 320nm and by spectrophotometric assays at wavelengths of 335 and 340nm. FAE activities varied dramatically among the seven exogenous enzyme preparations. Correlation between the enzyme activities determined by HPLC and spectrophotometric assays was high (r >0.98), but consistency among the different methods was poor, especially with the spectrophotometrical method (SP) at 335nm. Therefore, the SP by microplate reader at 340nm with standard substrate of methyl ferulate (MFA) was recommended for rapid analysis of large numbers of samples. Rumen fluid of steers had low, and different, ferulic acid esterase activity at different times of the day. Furthermore, high diurnal variation occurred for the ferulic acid esterase and other fibrolytic enzymes that were measured. The activity of FAE and other fibrolytic enzymes differed along with the diet compositions and feed intake. Diet C had the highest mean fibrolytic enzyme activity in the rumen, and diet A had the lowest activity of FAE and birchwood xylanase (BX). High correlations occurred between activities of carboxymethyl cellulase (CMC), BX, acetyl esterase (AE) and those of FAE, both with all data and within each diet. As an accessory enzyme, ferulic acid esterase should not be neglected in studies on furthering understanding of biodegradation of plant cell wall in rumen, and impacts of exogenous enzyme products. [Copyright &y& Elsevier]

Abstract: The evolution of grain boundaries (GBs) and shear bands in Cu bicrystals during one-pass equal-channel angular pressing (ECAP) was systematically investigated by various techniques. Four Cu bicrystals were designed to make GBs with angles of 0°, 45°, 90° and 135° with respect to the intersection plane (IP) of the ECAP die. After ECAP, the shear bands and the GB orientations in the four bicrystals displayed distinct behaviors due to the difference in the initial GB directions and the special crystallographic orientation of the component grains. Based on the experimental results, it is suggested that the initial GBs have a remarkable influence on the shear deformation behaviors of the adjacent regions, and the deformation regions far from the GBs are mainly controlled by the crystallographic orientations. The present investigations further demonstrate that shear deformation along the normal of the IP plays an important role in the deformation of Cu bicrystals. [Copyright &y& Elsevier]

The nitrided layer on Ni 45 (CoCrFe) 40 (AlTi) 15 high-entropy alloys (HEAs) was prepared by plasma nitriding. The microstructure, hardness, the effect of temperature on the tribological properties and adhesive strength of the nitride layer were investigated. The results revealed that the as-cast alloy was composed of a single FCC phase, and the hardness measured by nano-indentation was 8.8 GPa. After nitriding, the hard phases, such as AlN, CrN, Fe 3 N, and TiN, appeared, the surface hardness was increased to 14.9 GPa, and the hardness distribution of the cross section of the nitrided layer was uniform. Moreover, the scratch test showed that the nitrided layer had good bonding properties with the substrate. The friction coefficient and the wear rate were significantly reduced, compared to the as-cast alloys due to the generation of unique nitride particles on the surface of the nitrided alloys. At low temperatures, the friction mechanism of as-cast and nitrided alloys was dominated by the adhesive wear and abrasive wear. Subsequently, the friction mechanism was changed to the oxidative wear and delamination wear with increasing the temperature. [Display omitted] • Hard particles of AlN, CrN, Fe 4 N, and TiN phases were produced after nitriding. • The surface hardness of HEAs increased from 8.8 GPa to 14.9 GPa after nitriding. • The thickness of the nitrided layer on Ni 45 (FeCoCr) 40 (AlTi) 15 HEAs was 11.5 μm. • The wear resistance of nitrided HEAs was superior than that of as-cast HEAs. • Oxidative behavior played a dominant role in high wear resistance of HEAs. [ABSTRACT FROM AUTHOR]

Abstract: The morphologies and orientation relationships of Cu6Sn5 grains formed between Sn and (001), (011), (111) and (123) Cu single crystals under liquid- and solid-state aging conditions were systematically investigated. The regular prism-type Cu6Sn5 grains formed on (001) and (111) Cu single crystals are elongated either along two perpendicular directions or along three preferential directions with an angle of 60° between each pair of directions. The orientation relationships between Cu and Cu6Sn5 lattice structures were determined by electron backscatter diffraction and were explained in terms of their minimum misfit. However, on (011) and (123) Cu single crystal surfaces, the Cu6Sn5 grains were mainly scallop-type, with only a few regular prism-type grains. Furthermore, the regular prism-type Cu6Sn5 grains will change into scallop-type after long reflow or aging times. Meanwhile it is considered that the growth of the scallop-type grains is supplied by two fluxes: the flux of the interfacial reaction and the flux of ripening. However, the growth of the prism-type grains is only supplied by the flux of the interfacial reaction. The kinetics of IMCs growth between Sn and Cu single crystals was also investigated. [Copyright &y& Elsevier]

The cyclic deformation behavior of extruded magnesium alloy Mg–3%Al–1%Zn (AZ31) was studied under plastic strain amplitude and stress amplitude-control at room temperature. A significant cyclic hardening asymmetry of stress amplitudes between compression and tension was observed under constant plastic strain amplitude-controlled cycling. The possible reasons for this phenomenon are discussed by a combination of hysteresis loop analysis and in situ observation of twinning and untwinning during one loading cycle using electron backscatter diffraction. [Copyright &y& Elsevier]

An investigation was carried out into the microstructural evolution of the adiabatic shear bands generated under high-strain rate loading in a Fe–Cr–Ni single crystal. The results show that the distribution in plasticity on both sides of the bands during propagation is inhomogeneous, and recrystallization with an average grain diameter of 0.2μm may occur. These distortion-free nanograins are believed to form as the result of dynamic recrystallization. [Copyright &y& Elsevier]

Abstract: In vitro fermentation characteristics of soluble, washout, and non-washout fractions separated from barley and maize and their technologically processed (i.e., pressure toasting, pelleting and their combination) products were measured. The aim was to establish whether the soluble equaled the washout fraction, whether these fractions are rapidly and completely fermented, and whether their fermentation characteristics are the same. A simple fractionation method was developed to separate the whole grain into a soluble fraction, a washout fraction, an insoluble washout fraction, and a non-washout fraction. Proximate analysis of the different fractions revealed in the soluble fraction a large (>400gkg-1DM) residual organic matter component of unknown origin, while the insoluble washout fraction contained between 800 and 900gstarch/kgDM. Fermentation characteristics of all fractions as well as the whole grain were measured for 72h using gas and volatile fatty acids (VFA) production in vitro. After fractionation, gas and VFA production profiles of the fractions with different chemical compositions were found to be different. Based on gas production profiles it was shown that the soluble fraction was easily fermentable and was fermented faster than the insoluble washout and the non-washout fraction. Differences were however much smaller than anticipated, which would suggest that the extent of fermentation of washout fractions in the rumen is incomplete. The maximum gas and VFA production from the soluble fraction was always lower than that of the insoluble washout, and the non-washout fraction. The combination of pressure toasting and pelleting reduced fermentability both in terms of gas and VFA production compared with the other treatments. [Copyright &y& Elsevier]

Objective. The aim of this study is to investigate the prevalence of promotor CpG island methylation of the death-associated protein kinase (DAPK), p16, and O6-methylguanine-DNA methyltransferase (MGMT) genes in both tumor and plasma samples of cervical cancers.Methods. Methylation-specific PCR (MSP) was employed to detect promotor CpG island methylation of the DAPK, p16, and MGMT genes in 85 surgical tumor tissue samples and 40 pretreatment plasma samples from cervical cancers.Results. Promotor CpG island methylation of DAPK, p16, and MGMT was detectable, respectively, in 60%, 28.2%, and 18.8% of cases of cervical tumor DNA; and in 40%, 10%, and 7.5% of cases of patients'' plasma DNA. Moreover, at least one of the three methylated genes was detected in 75.3% (64/85) of cases of tumor and in 55% (22/40) of cases of plasma. Higher prevalence of methylation of DAPK was found in squamous cell carcinoma than in adenocarcinoma in both univariate and multivariate analysis. Methylation of p16 was significantly associated with that of MGMT in both univariate and multivariate analysis. The methylation pattern in primary tumor and plasma was found to be concordant in 23 patients with matched tissue and plasma samples. In cases positive for DAPK and p16 methylation in tumor, detection in the paired plasma sample was 64.3% (9/14) and 33.3% (3/9), respectively.Conclusions. Promotor CpG island methylation is a frequent event in cervical carcinogenesis. Detection of the methylated sequences in the circulation suggests that plasma DNA methylation warrants further study to determine its potential role in cancer management. [Copyright &y& Elsevier]

High-entropy alloys (HEAs) with a single-phase face-centered cubic (FCC) structure generally have excellent plasticity. However, its limited room temperature strength and hardness result in lower wear resistance, which hinders tribological and engineering applications. In this paper, the pack-boronizing method was used to improve the tribological properties of Al 0 · 1 CoCrFeNi HEAs with a single-phase FCC structure. The boronizing treatment was carried out at 900 °C for 2, 4, 6, and 8 h, respectively. The structure and phase formation of boronized alloys were studied. Moreover, the reciprocating sliding wear behavior of boronized alloys against Si 3 N 4 balls in dry and deionized water was investigated. A boronized layer with a double-layer structure was formed on the HEA surface, with a total thickness of about 17.3–58.5 μm. The wear mechanism of boronized alloy was transformed from the abrasive and delamination wear to the polishing effect with increasing the boronizing time in air. In contrast, the wear mechanism of boronized alloys in the deionized water gradually changed from the two-body to three-body wear with increasing the boronizing time. Meanwhile, the wear mechanism of the Si 3 N 4 counterface was also transformed to three-body wear gradually. • The maximum hardness of boronized HEAs is higher 7 times than that of annealed HEAs. • The wear rate of boronized HEAs was much lower than that of as-cast HEAs. • The wear mechanism of boronized HEAs in air was abrasive wear and polishing effect. • Wear mechanism of HEAs in deionized water was two-body and three-body abrasive wear. • The lubrication of deionized water led to lower friction coefficient and wear rate. [ABSTRACT FROM AUTHOR]

A recent paper on “microstructural evolution during high-temperature oxidation of Ti2AlC ceramics” (Cui et al., 2011 ) claims that the oxide product is solely TiO2 (rutile) when Ti2AlC is oxidized at 900°C for 1h. This comment presents experimental evidence and thermodynamic arguments confirming the formation of a primary Al2O3 layer instead of pure TiO2 scale under the same oxidation condition. [ABSTRACT FROM AUTHOR]

Compared with the Fe 40 Mn 20 Cr 20 Ni 20 high-entropy alloy in a homogenized state, it has higher incipient plastic strength after high-temperature aging, which is attributed to the generation of short-range orderings (SROs) caused by the local composition fluctuations. Based on nanoindentation results at different loading rates, the evolution trends of homogeneous and heterogeneous dislocation-nucleation modes under the effect of SROs are revealed. Under the action of the high-solution friction stress, which is caused by the high loading rate, and coherency-strain field, which is caused by SROs, the critical shear stress of the dislocation nucleation increases. Furthermore, with the increase of the loading rate, the probability of heterogeneous nucleation in homogenized samples increases, while that in aged samples is the opposite. From the perspective of the distribution of dislocation-nucleation sites, this opposite trend can be well explained by assuming the spreading resistance of an activatable region. In short, the present work reveals the pivotal role of SROs on dislocation-nucleation modes and paves the way for the quantitative study concerning SROs and their strengthening effects. [ABSTRACT FROM AUTHOR]

The Ti 62 Zr 12 V 13 Cu 4 Be 9 , Ti 58 Zr 16 V 10 Cu 4 Be 12 , Ti 46 Zr 20 V 12 Cu 5 Be 17 , and Ti 40 Zr 24 V 12 Cu 5 Be 19 metallic glass matrix composites (MGMCs) were prepared by copper mould casting. The corrosion resistance and the pitting susceptibility of Ti-based MGMCs were tested on their cross-sectional areas in 3.5 wt.% NaCl solutions by potentiodynamic polarization measurements. The composites with lower Ti contents (Ti 40 Zr 24 V 12 Cu 5 Be 19 and Ti 46 Zr 20 V 12 Cu 5 Be 17 ) exhibit a low resistance to the chloride induced pitting and local corrosion. The preferential dissolution of amorphous matrix is explained by the high chemical reactivity of beryllium element compared to that of stable dendrites and by the detected lower Ti and V contents. However, fairly good passivity was found in the composite with higher Ti contents (Ti 62 Zr 12 V 13 Cu 4 Be 9 ). XPS measurements revealed that protective Ti-enriched oxide film was formed on the composite surface, additionally, lower content of beryllium element in amorphous matrix hinder the selective corrosion of amorphous matrix. The assessment of experimental observation leads to a proposed corrosion mechanism involving selective dissolution of amorphous matrix and chloride induced pitting process. [ABSTRACT FROM AUTHOR]

Based on the microscopic mechanisms applicable to bulk metallic glasses (BMGs), such as the free-volume theory and fracture theory of brittle solids, a constitutive equation for the crack-like propagation velocity of shear bands in BMGs is deduced, ν SBcl = ν 0 a 0 exp (− E S / k T). Furthermore, a flow model of monolithic BMGs is successfully established, log ν SB = log (ν 0 a 0) + log e E S / (k T l) − log e E S / (k T). The model explains clearly the fundamental deformation of BMGs at the temperature far below the liquidus temperature, i.e., the mechanism of serrated flows. Not only does the model accurately predict the transition between serrated and non-serrated flows, but the Arrhenius equation and activation energy received by the current model for most BMGs are consistent with the experimental results. The current study paves a way to plastically process BMGs, avoiding catastrophic plasticity instability. [Display omitted] [ABSTRACT FROM AUTHOR]

Previous studies have revealed the presence of "inter-tumoral" heterogeneity of congenital melanocytic nevus (CMN), primary, and metastatic melanomas in patients using next-generation sequencing, suggesting that CMN cells evolve sporadically.1,2 Furthermore, in practice, tissue slides of melanomas arising from CMNs often show several melanoma cell clusters with different morphologies, even within a single lesion. Intra-tumoral heterogeneity and immune escape of melanoma arising from congenital melanocytic nevus revealed by spatial gene expression profiling The decreased B2M expression in melanoma cells may have reduced antigenicity and decreased lymphocyte infiltration by inducing immune evasion as melanoma progressed. [Extracted from the article]

The corrosion behavior of Zr 58.5 Ti 14.3 Nb 5.2 Cu 6.1 Ni 4.9 Be 11.0 metallic glass matrix composites (MGMCs) in different corrosive media, including 1 M NaCl, 1 M HCl, 0.5 M H 2 SO 4 , and 1 M NaOH solutions, was studied. The electrochemical characteristics of the composites were investigated by potentiodynamic-polarization measurements. The results show that the corrosion resistance in NaOH solution is the poorest in terms of the corrosion potential ( E corr ) and corrosion current density ( i corr ). For comparison, the chemical immersion tests were conducted. The corroded surface morphologies after electrochemical and immersion measurements both show that the amorphous matrix and crystalline dendrites exhibit different corrosion behaviors. The possible interpretation of the observed morphology evolution was proposed. The effect of a very base metallic element of beryllium on the corrosion dynamic process has been emphasized. [ABSTRACT FROM AUTHOR]