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Irregular grains, high interfacial stresses and anisotropic properties widely exist in 3D-printed metallic materials, and this paper investigated the effects of heat treatment on the microstructural, mechanical and corrosion properties of 316 L stainless steel fabricated by selective laser melting. Sub-grains and low-angle boundaries exist in the as-received selective laser melted (SLMed) 316 L stainless steel. After heat treatment at 1050 °C, the sub-grains and low-angle boundaries changed slightly, and the stress state and strength decreased to some extent due to the decrease of dislocation density. After heat treatment at 1200 °C, the grains became uniform, and the dislocation cells vanished, which led to a sharp decline in the hardness and strength. However, the ductility was improved after recrystallization heat treatment. The passive film thickness and corrosion potential of the SLMed 316 L stainless steel decreased after heat treatment, and the pitting potential also decreased due to the accelerated transition from metastable to steady-state pitting; this accelerated transition was caused by the presence of weak passive films at the enlarged pores after heat treatment, especially for an adequate solid solution treatment.

The multiple effects of ɳ-Ni3Ti precipitates and reversed austenite on the passive film stability of nickel-rich Custom 465 steel were studied. The results showed that with an increase in tempering temperature, the η-Ni3Ti precipitates gradually coarsened. The Volta potential of the ɳ-Ni3Ti/matrix interface was approximately 30 mV lower than that of the precipitates, which decreased the passive film stability. The volume of reversed austenite gradually increased at higher tempering temperatures. The Volta potential of the reversed austenite was 14 mV higher than that of the martensite, which enhanced the passive film stability and slightly increased the pitting corrosion resistance.

Laves phase segregation is a universal phenomenon in additive manufactured or as-cast Inconel 718 alloy, and the Laves phase usually degrades the mechanical properties of the matrix. In this work, nickel-based alloys designed with different Nb contents were successfully fabricated by laser metal deposition (LMD) via a dual-feed system, and the Laves phase distribution at the macro level was relatively uniform. The effects of Nb content on the microstructure, mechanical properties and surface potential of the as-received and heat-treated nickel-based alloys were investigated. The grain size of the as-received LMD nickel-based alloys decreased with the Nb content, and the Laves phase exhibited a universally higher nano-hardness but lower surface potential than the γ matrix. The nano-hardness of the Laves phase linearly increased, whereas the Volta potential decreased with the Nb content. The strength improvement for the as-received LMD nickel-based alloys with different Nb contents was equally attributed to grain refinement and enhancement of the Laves phase (both hardness and content), while the increase in the precipitate content (main γ″) as a function of Nb content contributed to the substantial improvement in hardness for the heat-treated LMD nickel-based alloys and the grain refinement strengthening effect was comparative minor after aging treatment.

The relationship between the microstructure of intergranular corrosion of SLM 316L SS was investigated in this study. The experimental results revealed that SLM 316L SS could be sensitized at 650 °C as the treatment duration was larger than 6 h. Formation of the precipitated phases that accelerated by the sub-grain boundaries was responsible for the high susceptibility of SLM 316L SS to intergranular corrosion.

In this work, the influence of reversed austenite on the intergranular corrosion of AM355MSSs (martensitic stainless steels) was investigated. The combined results revealed that the reversed austenite exhibited an inhibiting effect on the intergranular corrosion of AM355MSSs. The inhibiting effect of reversed austenite on the intergranular corrosion was summarized as follows. Firstly, the formation of reversed austenite at the Cr-depleted regions reduced the number of nucleation sites for intergranular corrosion. Secondly, the reversed austenite always distributed along the martensite lath boundaries, preventing the propagation of intergranular corrosion.

In order to improve the utilization efficiency of the waste from planting and breeding, through reviewing literature and field survey we knew about the number and present situation of the utilization of the waste in Shanxi Province and assessed the characteristics of quantity and spatial distribution on regional scale. Besides, we used the investigation to analyze the potential on the resource utilization and comprehensive utilization efficient way. Results showed that there were large quantities of straws of wheat in the south of Shanxi Province, and in the other regions corn straws played the most important situation. Livestock poultry dung was mostly from cattle, pigs and sheep, and it distributed as most of sheep in the northwestern, cattle in this north center, and pigs in the southeast. During 2007-2015, the crops straw produced from 1.27×107 t to 1.54×107 t, and the dung output of livestock and poultry came from 1.82×107 t to 2.02×107 t, and it showed a relatively stabilized tendency in recent years. If the waste from planting and breeding was converted into fertilizer we could get organic matter, N, P, K, respectively 1.54×107,1.25×105, 5.28×104, 1.04×105 t, and if energy-oriented we could get 1.05×107 t standard coal, or 4.59×109 m3 biogas. Therefore, the waste was diverse and numerous in Shanxi Province, and it had its own spatial distribution in each area. Besides, it had greater potential of resource. We should try our best to convert waste into fertilizer, energy, feed and other utilization ways in order to achieve a high efficient, comprehensive and integrated utilization. Based on the study, scientific and feasible guidance for Shanxi Province was put forward to realize a more efficient and sustainable utilization of waste from planting and breeding.

Passivation and film chemistry of 2507 super duplex stainless steel in modified artificial seawater (ASW) are investigated. Removal of dissolved oxygen decreases the electric field strength and point defect diffusivity of the passive film. Passive current density in acidified ASW is higher than that in aerated ASW due to increased potential drop across film/solution interface, donor density and point defect diffusivity. The content of oxidized Cr, Fe(II) and hydroxides increases and film thickness reduces with acidification. In acidified ASW, passive film become denser from pre-passivation to passivation region and pores form accompanied with the increase of oxidized Fe after transpassivation.

Potassium-ion batteries (KIBs) are promising alternatives to lithium-ion batteries (LIBs) due to the advantages of low-cost and abundant natural resource. To date, the researches on KIBs are still in their early stage and only a few materials have been explored. Herein, we design VN quantum dots encapsulated in ultralarge pillared N-doped mesoporous carbon microsheets (VN-QDs/CM) via a large-scale and ultrafast (within two minutes) solution combustion synthesis method and a subsequent ammonia reduction process. The VN quantum dots with high mass loading and dispersity on conductive carbon microsheets could reduce the K-intercalation stress in particle dimensions and mitigate the volume expansion. In addition, the ultralarge pillared N-doped mesoporous carbon microsheets not only facilitate the transfer of electrons and K ions and but also prevent the active materials from breaking away from the electrode during cycling. As an advanced anode material for KIBs, a high reversible capacity and a superior cycling stability (228 mAh g−1 at 0.1 A g−1 after 100 cycles, 215 mAh g−1 at 0.5 A g−1 after 500 cycles) are obtained, among the best anodes reported. More importantly, the effective strategy can be potentially used for mass production of quantum dots encapsulated in ultralarge carbon microsheets for energy storage.

Recently, the stainless steels produced by selective laser melting (SLM) have received considerable attention in biomedicine, but their corrosion behaviors in the body environment are not revealed clearly up to now. In this study, the fundamental research on influences of microstructures on corrosion behavior of 316L stainless steel (316L SS) produced by SLM was conducted simulated body fluid (SBF). Higher densities of grain boundary, sub-grain boundary and dislocation resulted in a thicker passive film forming on SLM 316L SS comparing with that of wrought sample in SBF. Composition analyses of passive films revealed that the excessive thickness was the outer layer. No sulfide and dislocation tangling around oxide inclusions in SLM 316L SS contributed to a 0.205 V nobler pitting potential of SLM 316L SS than that of the wrought in SBF.

Microstructural anisotropy widely exists in the additive manufactured components during the rapid solidification process, slender columnar grains were formed along the building direction due to the higher thermal gradient caused by the previously deposited layer heat sink. The resistance to deformation along the x-axis or y-axis was confirmed to be larger than that of the z-axis both for the bulk and porous selective laser melted 316L, which was attributed to that most of the grain boundaries were perpendicular to the loading direction for the first two axes. However, the anisotropy in the microstructure and mechanical property can be eliminated after recrystallization.

Different types of anion vacancies were optimized in passive films on copper via first-principles calculations based on density functional theory, and numerous potentiodynamic polarizations were performed to evaluate the size matching effect between anion vacancies and halide ions in passive film breakdown on copper. The size of the anion vacancies decreased to some extent compared with the corresponding atom due to the surface relaxation effect, and electrochemical experiments showed that the pitting potential for an oxide passive film on copper followed the order F−

Accelerated corrosion tests of the 7005-T4 aluminum alloy were conducted to determine a suitable service life prediction method by using alternating wet–dry cycles in three kinds of solutions. The morphology and composition analysis of the corrosion product revealed that slight corrosion occurred on the surfaces of the samples immersed in a 0.25wt% Na2S2O8 solution. However, pitting corrosion occurred on the surfaces of the samples immersed in a 3.5wt% NaCl solution, whereas exfoliation corrosion occurred on the surfaces of the samples immersed in a mixture of 0.25wt% Na2S2O8 and 3.5wt% NaCl solutions. A power exponent relationship was observed between the mass loss and exposure time of the 7005-T4 aluminum alloy immersed in the three kinds of solutions. In the mixture of 0.25wt% Na2S2O8 and 3.5wt% NaCl solutions, the mass loss of the aluminum alloy yielded the maximum value. Based on the calculation of the correlation coefficients, the alternating wet–dry procedure in a 3.5wt% NaCl solution could be used to predict the corrosion behavior of 7005-T4 aluminum alloy exposed in the atmosphere of Qingdao, China. The prediction model is as follows: T = 104.28·t0.91, where T is the equivalent time and t is the exposure time.

The correlation between the distribution/size of carbides and corrosion resistance of 17Cr-1Ni ferritic-martensitic stainless steel after different heat treatment temperatures was investigated by transmission electron microscope, electrochemical tests, and corrosion morphology observations. The results showed that the size of the precipitated phase decreased and corrosion resistance increased with an increase in the annealing temperature. When the tempering temperature was low (290 °C), carbides precipitated mainly at the phase boundaries due to a low degree of atomic matching and higher grain boundary energy. In this case, the polarization curve had a passivation interval and the pits were mainly initiated at the phase boundary. When the tempering temperature was higher than 400 °C, the carbides gradually precipitated in the martensite laths because the accelerated diffusion of Cr healed the Cr depletion zone at phase boundary. This outcome resulted in a polarization curve that had no passivation range and uniform corrosion occurred in martensitic region.

Pure copper, tin copper and beryllium copper were exposed to a harsh marine environment, and the effects of tin and beryllium addition on copper corrosion were systematically investigated and compared. The corrosion rate for pure copper was similar with that for tin copper, but significantly higher than that for beryllium copper, indicating an improvement in corrosion resistance due to the addition of beryllium. Pitting corrosion occurred in all investigated materials and the extent of pitting damage was in the order of pure copper > tin copper > beryllium copper. Flaking corrosion was prominent on tin copper plate after long-term exposure and the primary corrosion products in all materials were Cu2O, CuCl and Cu2Cl(OH)3. The tin content in the inner corrosion layer was higher than in the outer layer for tin copper, whereas beryllium accumulated at the outer layer of beryllium copper, confirmed by auger electron spectroscopy, and related corrosion mechanisms were proposed.

An emerging class of cellular inhibitory proteins has been identified that targets viral glycoproteins. These include the membrane-associated RING-CH (MARCH) family of E3 ubiquitin ligases that, among other functions, downregulate cell surface proteins involved in adaptive immunity. The RING-CH domain of MARCH proteins is thought to function by catalyzing the ubiquitination of the cytoplasmic tails (CTs) of target proteins, leading to their degradation. MARCH proteins have recently been reported to target retroviral envelope glycoproteins (Env) and vesicular stomatitis virus G glycoprotein (VSV-G). However, the mechanism of antiviral activity remains poorly defined. Here we show that MARCH8 antagonizes the full-length forms of HIV-1 Env, VSV-G, Ebola virus glycoprotein (EboV-GP), and the spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), thereby impairing the infectivity of virions pseudotyped with these viral glycoproteins. This MARCH8-mediated targeting of viral glycoproteins requires the E3 ubiquitin ligase activity of the RING-CH domain. We observe that MARCH8 protein antagonism of VSV-G is CT dependent. In contrast, MARCH8-mediated targeting of HIV-1 Env, EboV-GP, and SARS-CoV-2 S protein by MARCH8 does not require the CT, suggesting a novel mechanism of MARCH-mediated antagonism of these viral glycoproteins. Confocal microscopy data demonstrate that MARCH8 traps the viral glycoproteins in an intracellular compartment. We observe that the endogenous expression of MARCH8 in several relevant human cell types is rapidly inducible by type I interferon. These results help to inform the mechanism by which MARCH proteins exert their antiviral activity and provide insights into the role of cellular inhibitory factors in antagonizing the biogenesis, trafficking, and virion incorporation of viral glycoproteins.IMPORTANCE Viral envelope glycoproteins are an important structural component on the surfaces of enveloped viruses that direct virus binding and entry and also serve as targets for the host adaptive immune response. In this study, we investigate the mechanism of action of the MARCH family of cellular proteins that disrupt the trafficking and virion incorporation of viral glycoproteins across several virus families. This research provides novel insights into how host cell factors antagonize viral replication, perhaps opening new avenues for therapeutic intervention in the replication of a diverse group of highly pathogenic enveloped viruses.

Viral envelope glycoproteins are an important structural component on the surfaces of enveloped viruses that direct virus binding and entry and also serve as targets for the host adaptive immune response. In this study, we investigate the mechanism of action of the MARCH family of cellular proteins that disrupt the trafficking and virion incorporation of viral glycoproteins across several virus families., An emerging class of cellular inhibitory proteins has been identified that targets viral glycoproteins. These include the membrane-associated RING-CH (MARCH) family of E3 ubiquitin ligases that, among other functions, downregulate cell surface proteins involved in adaptive immunity. The RING-CH domain of MARCH proteins is thought to function by catalyzing the ubiquitination of the cytoplasmic tails (CTs) of target proteins, leading to their degradation. MARCH proteins have recently been reported to target retroviral envelope glycoproteins (Env) and vesicular stomatitis virus G glycoprotein (VSV-G). However, the mechanism of antiviral activity remains poorly defined. Here we show that MARCH8 antagonizes the full-length forms of HIV-1 Env, VSV-G, Ebola virus glycoprotein (EboV-GP), and the spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), thereby impairing the infectivity of virions pseudotyped with these viral glycoproteins. This MARCH8-mediated targeting of viral glycoproteins requires the E3 ubiquitin ligase activity of the RING-CH domain. We observe that MARCH8 protein antagonism of VSV-G is CT dependent. In contrast, MARCH8-mediated targeting of HIV-1 Env, EboV-GP, and SARS-CoV-2 S protein by MARCH8 does not require the CT, suggesting a novel mechanism of MARCH-mediated antagonism of these viral glycoproteins. Confocal microscopy data demonstrate that MARCH8 traps the viral glycoproteins in an intracellular compartment. We observe that the endogenous expression of MARCH8 in several relevant human cell types is rapidly inducible by type I interferon. These results help to inform the mechanism by which MARCH proteins exert their antiviral activity and provide insights into the role of cellular inhibitory factors in antagonizing the biogenesis, trafficking, and virion incorporation of viral glycoproteins.

Additional file 1. Appendix S1: The location of Guangxi in China. Appendix S2: Structured questionnaire at household level. Appendix S3: Semi-structured questionnaire at village level. Appendix S4: Semi-structured questionnaire at township level. Appendix S5: Measurement of independent variables. Appendix S6: Parameter estimation for null models at different levels.

Background Mandibular fracture healing is a complex process involving nerves and growth factors. Nerve growth factor (NGF) not only facilitates the maintenance of sympathetic neurite growth but also stimulates other growth factors that can promote the essential osteogenesis and angiogenesis for fracture healing. Therefore, it is necessary to analyze the combined effects of NGF, bone morphogenic protein-9 (BMP-9), and vascular endothelial growth factor (VEGF) to accelerate the healing of mandible fractures. Methods The models of mandible fracture with local nerve injury established in 48 rabbits were randomly divided into nerve growth factor group (NGF group), gelatin sponge group (GS group), blank group, and intact group. The recovery of nerve reflex was assessed by observing the number of rabbits with lower lip responses to acupuncture. The fracture healing was observed with visual and CBCT, and then callus tissues from the mandibular fracture area were collected for hematoxylin and eosin (HE) staining observation, and the expression of BMP-9 and VEGF in callus at different stages was detected by quantitative real-time PCR (qRT-PCR). Results Needling reaction in the lower lip showed the number of animals with nerve reflex recovery was significantly higher in the NGF group than that in the GS and blank groups at the 2nd and 4th weeks after the operation. The combined results of macroscopic observation, CBCT examination, and histological analysis showed that a large number of osteoblasts and some vascular endothelial cells were found around the trabecular bone in the NGF group and the amount of callus formation and reconstruction was better than that in the GS group at the 2nd week after the operation. The qRT-PCR results indicated that the expression levels of BMP-9 and VEGF in the four groups reached the highest values at the 2nd week, while the expression levels of both in the NGF group were significantly higher than that in the GS group. Conclusion The exogenous NGF could accelerate the healing of mandible fractures. This work will provide a new foundation and theoretical basis for clarifying the mechanism of fracture healing, thereby promoting fracture healing and reducing the disability rate of patients.

Mobile travel has become a significant trend due to the emergence of smartphones and mobile technology. Existing researches show that the integration of location-based services (LBS) is potentially adding significant values to the mobile tourism industry. The purpose of this study is to develop a location-based mobile application for theme park visitors to enhance their visiting experience. The application of location- based solutions such as interactive map, push notification services with geofencing and augmented reality tour guide will be involved in this study. Google Map SDK for Android, Google ARCore Sceneform, GeoFire and SQLite methodology is adopted to build the application. An online survey is conducted to evaluate the user acceptance for the mobile application by sending Android Package Kit (APK) to the users. The result shows that majority of respondents had positive attitude towards the application and agreed that the application will enhance their park visiting experience. The conclusion can be drawn that the application can be further improved with features which contributes to the digitalization of outdoor parks or other fields in mobile tourism.

The MARCH family of RING-finger E3 ubiquitin ligases comprise 11 members that have been reported to play a variety of roles in the downregulation of cell-surface proteins involved in adaptive immunity. The RING-CH domain of MARCH proteins is thought to ubiquitinate the cytoplasmic tails (CTs) of target proteins, leading to protein degradation through either lysosomal or proteasomal pathways. Three MARCH proteins (MARCH1, 2, and 8) have recently been reported to target the HIV-1 envelope glycoprotein (Env) and vesicular stomatitis virus G glycoprotein (VSV-G), thereby impairing the infectivity of HIV-1 virions bearing HIV-1 Env or VSV-G. However, the mechanism of antiviral activity remains poorly defined. Our data show that MARCH proteins antagonize the full-length forms of HIV-1 Env, VSV-G, and Ebola glycoprotein (GP), and impair the infectivity of HIV-1 virions bearing these viral glycoproteins. This Env-targeting activity of the MARCH proteins requires the E3 ubiquitin ligase activity of the RING-CH domain. We observe that the MARCH protein targeting of VSV-G is, to a large extent, CT-dependent. In striking contrast, the MARCH-protein targeting of HIV-1 Env and Ebola GP does not require the CT. Confocal microscopy data demonstrate that MARCH proteins are able to trap the viral glycoproteins in an intracellular compartment. We observe that the endogenous expression of MARCH8 in T-cell lines and PBMCs is inducible by type I interferons (a and b) and is also upregulated by HIV-1 infection. Current studies are aimed at identifying the cellular target for MARCH-mediated ubiquitination in the context of their antiviral activity. These results will clarify the mechanism by which MARCH proteins antagonize viral glycoproteins and provide insights into the antiviral role of cellular inhibitory factors in Env biogenesis, trafficking, and virion incorporation.

Fine gas-atomized powders were prepared for fabricating 316L stainless steel by selective laser melting (SLM) for medical implant applications. The effect of 3D printing laser power on the microstructure, biocompatibility, mechanical and corrosion properties of SLM 316L were systematically investigated and compared with the traditionally quenched. The SLM 316L showed irregular grains with many sub-grains and a thicker passive film with lower Mo content than the quenched 316L. SLM 316L formed at high laser power showed improved elongation, corrosion resistance, and biocompatibility, while that prepared at low power showed poorer performance and was unstable during long-term experiments in simulated body fluid. Keywords: 3D printing, 316L stainless steel, Selective laser melting, Transmission electron microscopy, Corrosion, Bio-compatibility