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Laser direct energy deposition (LDED) exhibits great potential for application in rail repairing due to its low cost and high process automation. However, the martensite transformation accompanied by rapid solidification leads to the decrease in the mechanical properties and threatens the service safety. In this study, the reinforcement strategy of combining cobalt (Co) addition with preheating treatment was investigated systematically by combining thermodynamic calculations with experimental characterization to optimize the microstructure and mechanical properties of U75V steel by LDED. The results indicate that cobalt addition can promote the pearlite percentage by facilitating the leftward shift of the continuous cooling transformation (CCT) curve, and refining the interlamellar spacing. But the martensite start (Ms) temperature will also increase from 206.4 °C to 324.1 °C after 7 wt% Co addition. 350 °C preheating treatment on the substrate can also promote the pearlite transformation by elevating the valley temperature of thermal cycling over Ms, as well as the subsequent decrease in cooling rate, but it is not sufficient to prevent martensite formation. A synergistic reinforcement strategy of 7 wt% Co addition and 350 °C preheating was established, which can effectively suppress the occurrence of martensite in the bottom area of deposition layers and expand the pearlite range in the top area. The bonding strength between the substrate and deposition layers has been elevated by ∼20%, accompanied by the increase in elongation and wear resistance. A mixed mode of adhesive and abrasive wear has transformed into a mode dominated by adhesive wear after optimization.

This study presented a comprehensive investigation into the microstructures, strengthening mechanisms and deformation behaviours of a novel N-doped Co-28Cr-6Mo (CCMN) alloy fabricated by laser powder bed fusion (LPBF). In addition to the well-known cellular structures, lattice defects including dislocations and stacking faults (SFs), the near-spherical shaped Cr2N precipitates with two typical size distributions were detected. Tensile test results revealed that the LPBF fabricated CCMN alloy demonstrated superior yield strength of 845 ± 49 MPa and elongation to fracture of 12.7 ± 1.9%. The grain boundaries (∼277 MPa), high density of dislocations (∼176–193 MPa), Cr2N precipitates (∼243 MPa) and SFs (∼131 MPa) are regarded as the dominate strengthening contributors. On the other hand, HCP phase triggered by strain induced martensite transformation (SIMT) and the Lomer-Cottrell locks (L-C locks) associated with the numerous SFs significantly enhanced the alloy strain hardening rate. More importantly, the formed Cr2N nanoprecipitates effectively suppressed the strain localisation and the premature failure along the HCP/FCC interfaces by deflecting the continuous growth of SFs, further contributing to the high ductility of the LPBF processed CCMN alloy. The present study is expected to shed light on the future development of N-doped high-performance cobalt-based alloy for the LPBF process.

In this paper, the skin-core combined with the triple contour method is proposed to solve the density and roughness problems of selective laser melting. Based on the skin-core strategy, the surface roughness is optimized by laser parameter adjustment, and the high-quality side-surface formation is achieved by the triple contour method. The results showed that the relative density increases first and then decreases with increasing in-skin energy density, and surface roughness decreases with increasing up-skin energy density. The effects of the skin-core parameters have been analyzed. In addition, a triple contour scanning strategy was also conducted, and the variation of surface roughness caused by the different number of contours has been analyzed, along with the fabrication of the Ti6Al4V denture bracket. Results showed that the inclined surface roughness could be improved by the triple contour method to an average roughness (Ra) of 3.5 µm. An average surface roughness of less than 4.3 µm and a relative density of 99.8% have been achieved at the same time using the skin-core and triple contour strategy. The curved surface and overhanging structure quality of the denture bracket was also improved. This work provided a novel approach for the additive manufacturing of a medical titanium alloy. [ABSTRACT FROM AUTHOR]

Impaired iron homeostasis has been proven to be one of the critical contributors to the pathology of Parkinson’s disease (PD). Ferritin is considered an intracellular protein responsible for storing cytosolic iron. Recent studies have found that ferritin can be secreted from cells independent of the classical endoplasmic reticulum–Golgi system. However, the precise mechanisms underlying the secretion of ferritin in the brain were not elucidated. In the present study, we demonstrated that the primary cultured astrocytes do have the ability to secrete ferritin, which is enhanced by iron treatment. Increased ferritin secretion was accompanied by increased protein expression of ferritin response to iron stimulation. Further study showed that iron-induced expression and secretion of ferritin could be inhibited by CQ or 3-MA pretreatment. In addition, the knockdown of transient receptor potential mucolipin 1 (TRPML1) antagonized iron-induced ferritin secretion, accompanied by further increased intracellular protein levels of ferritin. Further study demonstrated that ferritin colocalized with LAMP1 in iron-treated astrocytes. On the contrary, ras-associated protein 27a (Rab27a) knockdown further enhanced iron-induced ferritin secretion and decreased intracellular protein levels of ferritin. Furthermore, we also showed that the secretory autophagy protein tripartite motif containing 16 (TRIM16) and sec22b decreased in iron-treated astrocytes. These results suggested that astrocytes might secrete ferritin via TRPML1-mediated exocytosis. This provides new evidence for the mechanisms underlying the secretion of ferritin in primary cultured astrocytes under a high iron environment.

Purpose: To evaluate the clinical efficacy of polysaccharide iron complexes (PIC) plus vitamin C in treating iron deficiency anemia (IDA) during pregnancy and its effect on iron metabolism. Methods: Ninety pregnant women with IDA in their second trimester admitted into the Department of Gynaecology and Obstetrics, Nanchang Third Hospital, Jiangxi Province, China between June 2019 and June 2021 were randomly and equally assigned to receive either PIC (two 500 mg capsules daily) alone (control group) or PIC plus vitamin C (0.1 g daily) (study group) for 4 weeks. Efficacy was determined by changes in clinical symptoms and blood indices and iron metabolism indices (serum ferritin, serum iron, hepcidin, transferrin saturation) pre- and post-treatment. Adverse pregnancy outcomes were also recorded. Results: Both groups were comparable at baseline. Post-treatment, study group showed significantly higher red blood cell (RBC), hemoglobin (Hb), mean red blood cell volume (MCV) and mean corpuscular hemoglobin (MCH) compared to control group (p < 0.05). Iron metabolism indices also significantly improved in study group with serum ferritin (SF), serum iron (SI), hepcidin (Hepc), and transferrin saturation (TSAT) (p < 0.05). The total clinical efficacy was higher in study group (p < 0.05), and the incidence of adverse pregnancy outcomes was lower (p < 0.05). Conclusions: The combination of PIC with vitamin C significantly improves the hematological indices, enhances iron metabolism, and reduces adverse pregnancy outcomes compared to PIC alone in pregnant women with IDA. Further studies with larger sample sizes are warranted to validate these results. [ABSTRACT FROM AUTHOR]

The overgrazing and overutilization of pastures can lead to serious degradation that can be restored through proper management practices. However, little is known about the dynamic changes in soil microbial communities during such restoration processes. Therefore, we investigated the characteristics of changes in soil microbial communities during straw mulching and plant revegetation processes in an abandoned artificial pasture in Northeast China. We used 16S rRNA gene and ITS sequencing to analyze the composition and diversity of soil bacterial and fungal communities under control, straw mulching, Leymus chinensis revegetation, and straw mulching + L. chinensis revegetation treatments. Straw mulching was effective in enhancing the contents of total N, alkali-hydrolyzable N, and available P in soils under plant revegetation. The alpha diversity indexes of both bacterial and fungal communities decreased under all treatments. Plant revegetation and straw mulching had an additive effect on the bacterial community composition; their combination increased the absolute abundances of copiotrophic phyla, including Proteobacteria, Actinobacteria, Gemmatimonadetes, Bacteroidetes, and Acidobacteria. However, the response of the fungal community to these treatments was minimal. Moreover, redundancy analysis showed that the soil total N was the most important soil factor affecting the bacterial and fungal community compositions. Our findings highlight the additive effects of straw mulching and revegetation on soil microhabitats and soil bacterial communities, which enhanced the soil quality in an abandoned artificial pasture in Northeast China.

The campaign life of a blast furnace is largely limited by the erosion state of its hearth section. Therefore, the study of hearth erosion is important for blast furnace ironmaking. In this study, the hearth erosion of the WISCO No. 1 blast furnace was investigated in combination with the numerical analysis of the iron flow and heat transfer in the hearth. The distributions of the wall shear stress and the temperature in the hearth were simulated and the hearth sections with high erosion risk were discussed. The hearth lining with higher shear stress is generally located near the taphole region and the 1423 K isotherm is totally located inside the hearth lining structure, with a deeper position in the central part of the hearth bottom. Based on the measurement data from the hearth damage investigation, the erosion state of the hearth bottom and the lower part of the hearth sidewall is more serious. The erosion line at the hearth bottom showed a typical “pot-bottom” shaped contour and for the hearth corner section, the average erosion depth was about 1/3 of the total wall thickness. The empirical expressions between the hearth erosion depth and the wall shear stress and the temperature were established. Moreover, the effects of key iron tapping factors on the wall shear stress and the effect of the hearth’s refractory structure on the heat transfer in the hearth are respectively discussed, aiming to provide more suggestions for hearth protection.

Nedd4 family interacting protein 1 (Ndfip1) is an adaptor of Nedd4-family ubiquitin ligases. Experimental results showed that Ndfip1 had a potential neuroprotective effect in neurology diseases. However, the neuroprotective effect and the underlying mechanisms of Ndfip1 in Parkinson's disease (PD) have not yet been fully elucidated. Therefore, in this study, we explored the neuroprotective effect of Ndfip1 against mitochondrial complex I inhibitor rotenone in a human dopaminergic neuroblastoma SH-SY5Y cell line and further elucidated its possible underlying mechanisms. Our results showed that rotenone could induce the up-regulation of α-synuclein (α-syn) in both mRNA and protein levels. The expression of Ndfip1 decreased at 24 h after rotenone treatment. Further study showed that high expression of Ndfip1 could protect SH-SY5Y cells against rotenone-induced neurotoxicity and antagonize the rotenone-induced increase in α-syn protein levels. In addition, high expression of Ndfip1 inhibited rotenone-induced increase in the protein levels of caspase-3 and decrease in tyrosine hydroxylase (TH). Further study showed that Ndfip1 did not affect the protein expression of iron regulatory protein 1 (IRP1), transferrin receptor 1 (TfR1), while antagonized the increase in protein levels of P62 and ferritin L caused by rotenone. Our findings provide specific identification of Ndfip1 proteins to inhibit the increase of α-syn in rotenone-induced SH-SY5Y cells. Ndfip1 might be a new theoretical drug target for the prevention and treatment of PD.

Abstract Histone crotonylation is a new lysine acylation type of post-translational modification (PTM) enriched at active gene promoters and potential enhancers in yeast and mammalian cells. However, lysine crotonylation in nonhistone proteins and plant cells has not yet been studied. In the present study, we performed a global crotonylation proteome analysis of Nicotiana tabacum (tobacco) using high-resolution LC-MS/MS coupled with highly sensitive immune-affinity purification. A total of 2044 lysine modification sites distributed on 637 proteins were identified, representing the most abundant lysine acylation proteome reported in the plant kingdom. Similar to lysine acetylation and succinylation in plants, lysine crotonylation was related to multiple metabolism pathways, such as carbon metabolism, the citrate cycle, glycolysis, and the biosynthesis of amino acids. Importantly, 72 proteins participated in multiple processes of photosynthesis, and most of the enzymes involved in chlorophyll synthesis were modified through crotonylation. Numerous crotonylated proteins were implicated in the biosynthesis, folding, and degradation of proteins through the ubiquitin-proteasome system. Several crotonylated proteins related to chromatin organization are also discussed here. These data represent the first report of a global crotonylation proteome and provide a promising starting point for further functional research of crotonylation in nonhistone proteins.

Silica optical film specifications are determined by their processing capability and their fabrication stability. Here, a statistical process control (SPC) approach usually used in planar lightwave circuits (PLC) is adopted to analyze the stability of the silica optical film fabrication process. Apart from the raw materials, certain key external factors have to be taken into consideration during the PLC process, such as temperature, relative humidity, process variation and machine aging. The fabrication process can be adjusted according to SPC-based results in real-time, so as to produce high quality silica optical film. By using this method, it is possible to assess the effectiveness of older production lines and extend their production capacity at minimal cost.