Inconel-718 has received an extensive using in mold industry. The selective laser melting (SLM) is providing an ideal means for manufacturing mold insert with complex geometrical features and ...internal architecture. During the manufacturing of high quality mold inserts with conformal cooling channel, the parameters play a vital role in the SLM process. In the study, the Inconel-718 alloys were manufactured by SLM with 2×2mm2, 3×3mm2, 5×5mm2, and 7×7mm2 island scanning strategies. The microstructure, mechanical property, and residual stress were investigated by optical microscope, tensile test and Vickers micro-indentation, respectively. It can be found that the relative density increased with enlarging the island size; the results on the microstructure indicated that the cracks and more pores were detected in the 22-specimen; whilst the microstructures of all specimens were composed of fine dendritic grains, cellular, and columnar structures; the tensile testing suggested that the ultimate tensile strength and yield strength of all samples was similar; while the outcome of the residual stress showed that the value of residual stress was ranked in the following sequence: 22-specimen<55-specimen<77-specimen<33-specimen. Although the 22-specimen had lower residual stress compared with the other groups, the occurrence of cracks limited its processing application in SLM. Through integrated into account, the 55-scanning strategy is a promising candidate for manufacturing of mold inserts.
•Laser scanning strategies in selective laser melted Inconel-718 were studied.•The analysis of mechanical property and residual stress were proposed.•The island scanning strategy affected the formation of pores and cracks.
We have investigated the capability of single-walled carbon nanotubes (SWNTs) to penetrate the cell wall and cell membrane of intact plant cells. Confocal fluorescence images revealed the cellular ...uptake of both SWNT/fluorescein isothiocyanate and SWNT/DNA conjugates, demonstrating that SWNTs also hold great promise as nanotransporters for walled plant cells. Moreover, the result suggested that SWNTs could deliver different cargoes into different plant cell organelles.
In recent years, Shanghai has entered a stage of microscale land subsidence, but the uneven subsidence is still significant, with long-term impacts on the operational safety of subways and other ...infrastructures. On the basis of 154 high-resolution Terra Synthetic Aperture Radar-X (TerraSAR-X) images captured from 2013 to 2020 and the time-series persistent scatterer-interferometric SAR (PS-InSAR) method, the land subsidence along the subways in Shanghai was acquired, and the levelling data of 56 benchmarks were used to validate the measurements derived by PS-InSAR. The results indicated that the two data sets agreed well, with a correlation coefficient of 0.9 and maximum D-value of 4.0 mm derived from six pairs of comparative data sequences. The proportion of PS points showing deformation rates between −3.0 mm/a and 3.0 mm/a reached 99.4%. These results indicated that the land subsidence trend along the subway was relatively stable overall, while significant deformation was distributed mainly along the suburban subways, especially the lines that were newly open to traffic, such as Line 5 and the Pujiang line (PJ Line); along these lines, the proportions of PS points with deformation rates exceeding ±3 mm/a were 7.2% and 7.6%, respectively, and the proportions were much smaller in the other lines. The maximum cumulative deformation (MCD) along the subways was located between Jiangchuan Road Station and Xidu Station of Line 5 with a value of −66.4 mm, while the second and third MCDs were −48.2 mm along Line 16 and −44.5 mm along PJ Line, respectively. Engineering constructions, such as human-induced ground loads, foundation pit constructions, and road constructions, were the main factors affecting local land subsidence. The analysis results also showed that land subsidence was relatively significant during the period before the subways were open to traffic due to subway construction, while land subsidence clearly slowed after the subway lines were open to traffic. This deceleration in land subsidence was closely related to the rise in the groundwater level.
In the study, the microstructure, mechanical property and metal release behavior of selective laser melted CoCrW alloys under different solution treatment conditions were systemically investigated to ...assess their potential use in orthopedic implants. The effects of the solution treatment on the microstructure, mechanical properties and metal release were systematically studied by OM, SEM, XRD, tensile test, and ICP-AES, respectively. The XRD indicated that during the solution treatment the alloy underwent the transformation of γ-fcc to ε-hcp phase; the ε-hcp phase nearly dominated in the alloy when treated at 1200°C following the water quenching; the results from OM, SEM showed that the microstructural change was occurred under different solution treatments; solution at 1150°C with furnace cooling contributed to the formation of larger precipitates at the grain boundary regions, while the size and number of the precipitates was decreased as heated above 1100°C with the water quenching; moreover, the diamond-like structure was invisible at higher solution temperature over 1150°C following water quenching; compared with the furnace cooling, the alloy quenched by water showed excellent mechanical properties and low amount of metal release; as the alloy heated at 1200°C, the mechanical properties of the alloy reached their optimum combination at UTS=1113.6MPa, 0.2%YS=639.5MPa, and E%=20.1%, whilst showed the lower total quantity of metal release. It is suggested that a proper solution treatment is an efficient strategy for improving the mechanical properties and corrosion resistance of As-SLM CoCrW alloy that show acceptable tensile ductility.
Large-scale reclamation projects during the past decades have been recognized as one of the driving factors behind land subsidence in coastal areas. However, the pattern of temporal evolution in ...reclamation settlements has rarely been analyzed. In this work, we study the spatio-temporal evolution pattern of Linggang New City (LNC) in Shanghai, China, using space-borne synthetic aperture radar interferometry (InSAR) methods. Three data stacks including 11 X-band TerraSAR-X, 20 L-band ALOS PALSAR, and 35 C-band ENVISAT ASAR images were used to retrieve time series deformation from 2007 to 2010 in the LNC. An InSAR analysis from the three data stacks displays strong agreement in mean deformation rates, with coefficients of determination of about 0.9 and standard deviations for inter-stack differences of less than 4 mm/y. Meanwhile, validations with leveling data indicate that all the three data stacks achieved millimeter-level accuracies. The spatial distribution and temporal evolution of deformation in the LNC as indicated by these InSAR analysis results relates to historical reclamation activities, geological features, and soil mechanisms. This research shows that ground deformation in the LNC after reclamation projects experienced three distinct phases: primary consolidation, a slight rebound, and plateau periods.
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•Personalized 3D-printed absorbable pancreaticojejunostomy device made by PPDO/PLA.•The proportion of PPDO/PLA affects degradability and mechanical properties.•PPDO/PLA has good cell ...adhesion performance and biocompatibility.
Poly (p-dioxanone) (PPDO) and poly (lactic acid) (PLA) were melt blended to prepare PPDO/PLA blends in this study, and 3D printing technology was used to prepare personalized pancreaticojejunostomy devices. By testing the degradation properties, mechanical properties, thermal stability, biocompatibility, hydrophilicity, and cell adhesion in vitro and in vivo, a suitable ratio of PPDO/PLA was selected as the material for the pancreaticojejunostomy device. The results show that the pancreaticojejunostomy device can be fabricated by PPDO/PLA blends using fused filament fabrication (FFF) 3D printing. As the proportion of PPDO increases, its degradation rate gradually increases, and its hydrophilicity improves, which is more conducive to cell adhesion and proliferation, while its mechanical properties gradually decrease. However, compared with soft tissues, it can still provide longer-term support strength to avoid early anastomotic stenosis. The mass loss rate in vivo was significantly faster than that in vitro, and the degradation rate of 50% PPDO/PLA at 3 months was 46.04 ± 5.79%. With the absorption and metabolism of the degradation products, there is no obvious toxic to the important organs in the body. Therefore, 50% PPDO/PLA has a suitable degradation time, mechanical properties, and good biocompatibility and has great application potential in manufacturing 3D pancreaticojejunostomy devices.
The electrochemical corrosion behaviors of as-SLMed CoCrW alloy after different heat treatments were investigated in 0.9% NaCl solution with and without the fluoride ions by open circuit potential ...(OCP), potentiodynamic polarization, electrochemical impedance measurements (EIS). The results showed that the SLMed CoCrW with a homogeneous structure experienced heat treated at 1150 °C followed by water quenching exhibited the better corrosion resistance to the electrolyte, whereas the alloy heat treated at 1150 °C followed by furnace cooling with a large amount of continuous blocky precipitates was susceptible to the corrosion. The XPS results indicated that the fluoride ions addition promoted the absorption of F−, Cl− and Na+ on the passive film. The fluoride ions slightly accelerated the corrosion of the SLMed CoCrW alloy by changing the composition of the passive film, thereby reducing the protectiveness of the film. Accordingly, a corrosion mechanism associated with the fluoride ion to the as-SLMed CoCrW alloy was proposed herein.
•The corrosion behaviors of SLMed CoCrW alloy with different heat treatments were studied.•A fine microstructure of SLMed CoCrW alloy exhibits good corrosion resistance.•The F− leads to formation of Cr(OH)3 and Cr-F or Cr-Cl complex in the passive film.
•A novel hydrolyzate-tolerant Aurantiochytrium sp. FN21 mutant strain was obtained.•Aurantiochytrium sp. FN21 can accumulate lipid and DHA using hydrolyzate medium.•Higher DHA production is achieved ...by the mutant than its parental strain.•The key genes and cellular pathways associated with tolerance are illustrated.
To utilize lignocellulosic hydrolysate for docosahexaenoic acid (DHA) production, a novel mutant Aurantiochytrium sp. FN21 with strong tolerance against inhibitory lignocellulosic hydrolysate was obtained through continuous domestication processes from the parent strain Aurantiochytrium sp. FJU-512. Aurantiochytrium sp. FN21 can accumulate 21.3% and 30.7% more DHA compared to its parent strain cultured in fermentation medium and a medium with 50% (v/v) sugarcane bagasse hydrolysate (SBH), respectively. After optimization with different nitrogen sources, the highest lipid (11.84g/L) and DHA (3.15g/L) production were achieved in SBH. The results demonstrated that Aurantiochytrium sp. FN21 has the commercial applications for DHA production using lignocellulosic hydrolysate. In order to elucidate the tolerance mechanism, transcriptomic profiling of the two strains was studied. The highly up-regulated genes and corresponding cellular pathways (TCA cycle, amino acid biosynthesis, fatty acid metabolism and degradation of aromatic compounds) are considered to be associated with the hydrolysate-tolerance of Aurantiochytrium sp. FN21.
Abstract Despite extensive research on the relationship between choline and cardiovascular disease (CVD), conflicting findings have been reported. We aim to investigate the relationship between ...choline and CVD. Our analysis screened a retrospective cohort study of 14,663 participants from the National Health and Nutrition Examination Survey conducted between 2013 and 2018. Propensity score matching and restricted cubic splines was used to access the association between choline intake and the risk of CVD. A two-sample Mendelian randomization (MR) analysis was conducted to examine the potential causality. Additionally, sets of single cell RNA-sequencing data were extracted and analyzed, in order to explore the role of choline metabolism pathway in the progression and severity of the CVD and the underlying potential mechanisms involved. The adjusted odds ratios and 95% confidence intervals for stroke were 0.72 (0.53–0.98; p = 0.035) for quartile 3 and 0.54 (0.39–0.75; p < 0.001) for quartile 4. A stratified analysis revealed that the relationship between choline intake and stroke varied among different body mass index and waist circumference groups. The results of MR analysis showed that choline and phosphatidylcholine had a predominantly negative causal effect on fat percentage, fat mass, and fat-free mass, while glycine had opposite effects. Results from bioinformatics analysis revealed that alterations in the choline metabolism pathway following stroke may be associated with the prognosis. Our study indicated that the consumption of an appropriate quantity of choline in the diet may help to protect against CVD and the effect may be choline-mediated, resulting in a healthier body composition. Furthermore, the regulation of the choline metabolism pathway following stroke may be a promising therapeutic target.
Building change detection (BCD) plays a vital role in city planning and development, ensuring the timely detection of urban changes near metro lines. Synthetic Aperture Radar (SAR) has the advantage ...of providing continuous image time series with all-weather and all-time capabilities for earth observation compared with optical remote sensors. Deep learning algorithms have extensively been applied for BCD to realize the automatic detection of building changes. However, existing deep learning-based BCD methods with SAR images suffer limited accuracy due to the speckle noise effect and insufficient feature extraction. In this paper, an attention-guided dual-branch fusion network (ADF-Net) is proposed for urban BCD to address this limitation. Specifically, high-resolution SAR images collected by TerraSAR-X have been utilized to detect building changes near metro line 8 in Shanghai with the ADF-Net model. In particular, a dual-branch structure is employed in ADF-Net to extract heterogeneous features from radiometrically calibrated TerraSAR-X images and log ratio images (i.e., difference images (DIs) in dB scale). In addition, the attention-guided cross-layer addition (ACLA) blocks are used to precisely locate the features of changed areas with the transformer-based attention mechanism, and the global attention mechanism with the residual unit (GAM-RU) blocks is introduced to enhance the representation learning capabilities and solve the problems of gradient fading. The effectiveness of ADF-Net is verified using evaluation metrics. The results demonstrate that ADF-Net generates better building change maps than other methods, including U-Net, FC-EF, SNUNet-CD, A2Net, DMINet, USFFCNet, EATDer, and DRPNet. As a result, some building area changes near metro line 8 in Shanghai have been accurately detected by ADF-Net. Furthermore, the prediction results are consistent with the changes derived from high-resolution optical remote sensing images.
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