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Wood-plastic composites (WPCs), combined with wood particles as filler and plastic as matrix material, is a kind of sustainable (if recyclable polymer is used) and environment-friendly material. Additive manufacturing (AM), as its high-precision and cost-saving characteristics, provides the possibility for the formation of WPCs with complex structure. Therefore, this study systematically described the techniques and recent progress of WPCs formed by AM, including the preparation of original WPCs, preprocessing of WPCs used in AM, several available AM processes for WPCs, as well as current applications and prospects. This research is expected to lay the foundation for the high-value application of WPCs. [ABSTRACT FROM AUTHOR]

The resolution of electronic devices toward miniaturization and lightweight puts forward requirements for current carrying capacity and density of conductors. Composite conductors consisting of copper as the matrix material and nanocarbon as the filler have aroused great interest, which revealed apparently enhanced ampacity and low density compared to pure Cu. In this study, three-dimensional laser-induced graphene (LIG) was used as the nanocarbon filler to improve the ampacity of Cu by a two-step electrodeposition method. After organic Cu seeding and a subsequent aqueous densification process, a uniformly dispersed graphene/copper dual network composite was obtained. This composite exhibits an enhanced ampacity of 1.34 × 105 A/cm2 (increased 76% compared with pure Cu) and a low density of 3.27 g/cm2 (36.5% of pure Cu). Benefiting from the patterning preparation of laser direct writing technology, this method enables the creation of conductive lines with various desired carves. Thus, this graphene–Cu composite conductor would be useful to overcome the current limit in Cu conductors and cables for lightweight high-power electrical energy transfer devices. [ABSTRACT FROM AUTHOR]

The triply periodic minimal surface (TPMS) structure of NiTi has gained significant attention owing to its potential for reusable buffer devices. However, the manufactured NiTi TPMS structure still faces challenges such as uneven pore distribution and numerous internal defects, primarily because of the lack of a design theory. Laser powder bed fusion technology has emerged as a promising approach for producing NiTi alloys and TPMS structures, affording substantial advantages. Thus, this study focused on designing and manufacturing three volume-fraction sheeted gyroid lattice structures by using laser powder bed fusion technology. Among the three structures, the VF15 gyroid lattice structure demonstrates the highest values for the compressive modulus (741.42 MPa), nominal yield strength (42.26 MPa), and ultimate yield strength (152.21 MPa). The findings highlight the effectiveness of laser powder bed fusion in preparing NiTi TPMS structures. In general, the utilization of laser powder bed fusion technology for fabricating NiTi TPMS structures combines the strengths of both the NiTi alloy and TPMS structures, resulting in outstanding buffering and shape memory capabilities. Therefore, the findings have potential applicability in efficient and secure reversible energy absorption devices. [ABSTRACT FROM AUTHOR]

The formation of microcracks at the interface of steel–copper heterostructures is prone to premature failure, which severely limits the application of heterostructure components. Herein, a new approach was proposed by doping nano-TiC in interface forming by laser powder bed fusion (L-PBF) to prevent the hot crack nucleation and block the solid-state crack propagation in steel–copper heterostructures. Benefitting from the TiC doping, the tensile strength of laminated steel–copper structures increased from 372 to 526 MPa. The findings of this research present a new approach to inhibit cracking in the fabrication of heterostructure component manufacturing using L-PBF. By doping nano-TiC particles into the steel–copper bimetallic interface, Hot crack nucleation and solid-state crack propagation were inhibited, and the crack-free steel–copper heterostructures were successfully prepared using LPBF. [ABSTRACT FROM AUTHOR]

Micron-sized particles are prone to deposit on smooth surfaces. A micron-sized particle collision-deposition model including the effects of electrostatic forces, integrated with the factors of particle size, material properties, elastic–plastic deformation, particle charging, surface roughness, and van der Waals forces, is proposed. The effects of the electrostatic forces on the critical deposition velocity, collision duration, and coefficient of restitution (COR), which is the ratio of particle velocity after and before the collision, are investigated for 1–20 μm sand particles colliding with glass, steel, and aluminum alloy surfaces. The results show that the electrostatic forces of sand particles are approximately 106–108 times their gravity and increase the impact duration. Moreover, these forces increase the critical deposition velocity by 2.32–6.89% for the glass surface and decrease the COR by 0.6–3.5% for the three surfaces, while the particle size is below 20 μm and the roughness is 1 nm. The electrostatic forces ranked from the maximum to the minimum are those of the aluminum alloy, steel, and glass surfaces for the same particle size and surface roughness. The developed model can perfect the theory of particle flow and gas-particle two-phase flow. [ABSTRACT FROM AUTHOR]

In this article, long‐lasting anti‐corrosion graphene/epoxy coatings were successfully prepared using quinacridone as dispersant by solution mixing method. The results showed that quinacridone and graphene can form π–π bonds and improve the dispersibility of each other in epoxy coatings. Mechanical and anti‐corrosion properties of epoxy coatings with different contents of quinacridone and graphene have been tested, the results showed that the optimum weight ratio of graphene to quinacridone was 2:5. The tensile strength of the epoxy coatings with 0.2 wt% graphene and 0.5 wt% quinacridone reached 8.12 MPa, which was 1.44 times of the pure epoxy coatings. Moreover, the impedance modulus of the coatings reinforced with quinacridone and graphene was greater than 1011 Ω·cm2 after being immersed in 3.5 wt% NaCl solution for 140 days, which was two orders of magnitude higher than that of the pure epoxy coatings. We found that the reason for the improved performance of the epoxy coatings was not only that quinacridone improved the dispersibility of graphene in the coatings, but also more importantly, quinacridone adsorbed on the surface of graphene to form scale‐like crystalline structures, which enables graphene to reduce folds and wrinkles, thus giving full play to the shielding effect of graphene against corrosion factors. [ABSTRACT FROM AUTHOR]

2D‐C/HfC–SiC composites were prepared by a combination of precursor infiltration and pyrolysis (PIP) and chemical vapor infiltration (CVI). Creep tests were performed at 1100°C in air under different stress conditions. Unlike most, C/SiC and SiC/SiC ceramic matrix composites only underwent primary and secondary creep stages, and the C/HfC–SiC composites underwent tertiary creep stage in the creep process. The reason was that the mechanical properties of C/HfC–SiC materials prepared by PIP + CVI methods were different from those prepared by traditional methods. The microscopic morphological analysis of the sample fracture showed that the oxidation products SiO2 and Hf–Si–O glass phases of the HfC–SiC matrix played a crack filling role in the sample during creep. In turn, it provided effective protection to the internal fibers of the sample. The creep failure of C/HfC–SiC composites in a high‐temperature oxidizing atmosphere was caused by the oxidation of the fibers. The total creep process was dominated by the oxidation of carbon fibers. It is noteworthy that there was the generation of HfxSiyOz nanowires in the samples after high‐temperature creep. The analysis of the experimental data showed that the creep stress had a linear negative correlation with the creep life. [ABSTRACT FROM AUTHOR]

Manufacturing abrasion‐resistant superhydrophobic matters is challenging due to the fragile feature of the introduced micro‐/nanoscale surface roughness. Besides the long‐term durability, large scale at meter level, and 3D complex structures are of great importance for the superhydrophobic objects used across diverse industries. Here it is shown that abrasion‐resistant, half‐a‐meter scaled superhydrophobic objects can be one‐step realized by the selective laser sintering (SLS) 3D printing technology using hydrophobic‐fumed‐silica (HFS)/polymer composite grains. The HFS grains serve as the hydrophobic guests while the sintered polymeric network provides the mechanical strength, leading to low‐adhesion, intrinsic superhydrophobic objects with desired 3D structures. It is found that as‐printed structures remained anti‐wetting capabilities even after undergoing different abrasion tests, including knife cutting test, rude file grinding test, 1000 cycles of sandpaper friction test, tape test and quicksand impacting test, illustrating their abrasion‐resistant superhydrophobic stability. This strategy is applied to manufacture a shell of the unmanned aerial vehicle and an abrasion‐resistant superhydrophobic shoe, showing the industrial customization of large‐scale superhydrophobic objects. The findings thus provide insight for designing intrinsic superhydrophobic objects via the SLS 3D printing strategy that might find use in drag‐reduce, anti‐fouling, or other industrial fields in harsh operating environments. [ABSTRACT FROM AUTHOR]

Objective: Prevention of fragility fractures is one of the public health priorities worldwide, whilst the incidence of osteoporotic vertebral compression fractures (OVCF) continues to rise and lacks the corresponding accurate prediction model. This study aimed to screen potential causes and risk factors for primary non‐traumatic osteoporotic vertebral compression fractures (NTOVCF) in the elderly by characterizing a patient population with NTOVCF and comparing it with a population of osteoporotic patients. Methods: Between January 2013 and January 2022, 208 elderly patients with unequivocal evidence of bone fragility manifested as painful NTOVCF were enrolled, and compared with 220 patients with osteoporosis and no fractures. The demographic data, bone turnover markers, blood routine, serum biochemical values, and radiological findings were investigated. Differences between the fracture and non‐fracture groups were analyzed, and variables significant in univariate analysis and correlation analysis were included in the logistic analysis to build the risk prediction model for osteoporotic vertebral fractures. Univariate analysis using student's t‐tests for continuous variables or a chi‐squared test for categorical variables was conducted to identify risk factors. Results: No significant differences were revealed regarding age, gender, BMI, smoking, alcohol consumption, blood glucose, propeptide of type I procollagen (P1NP), and N‐terminal middle segment osteocalcin (N‐MID) (P > 0.05). Parathyroid Hormone (PTH), 25(OH)D, serum albumin (ALB), hemoglobin (HB), bone mineral density (BMD), and cross‐sectional area (CSA) of the paraspinal muscle in the fracture group were significantly lower than those in the control group; however, b‐C‐terminal telopeptide of type I collagen (β‐CTX), total cholesterol (TC), high‐density lipoprotein cholesterol (HDL‐C), non‐prostatic acid phosphatase (NACP), and fatty degeneration ratio (FDR) were significantly higher than those in the control group (P < 0.05). Logistic regression analysis showed that ALB, HB, CSA, and BMD were negatively correlated with NTOVCF, while β‐CTX, HDL‐C, NACP, and FDR were positively correlated with NTOVCF. Conclusion: Decreased physical activity, anemia, hypoproteinemia, imbalances in bone metabolism, abnormal lipid metabolism, and degenerative and decreased muscle mass, were all risk factors for OVCF in the elderly, spontaneous fractures may be the consequence of cumulative declines in multiple physiological systems over the lifespan. Based on this risk model, timely detection of patients with high OVCF risk and implementation of targeted preventive measures is expected to improve the effect of fracture prevention. [ABSTRACT FROM AUTHOR]

AS41 magnesium alloy possesses outstanding performance features such as light weight, high strength to toughness ratio and excellent heat resistance due to the addition of Si element, while traditional casting methods are prone to inducing large grain size and coarse Mg2Si phase. In this study, we first reported utilizing the selective laser melting (SLM) technique, fabricating AS41 samples and exploring the effect of laser energy densities on the metallurgical quality by characterizing and investigating the microstructure and mechanical properties. Results showed that the optimal laser energy density range was 60 to 100 J/mm3. Average grain size of only 2.9 μm was obtained with weak texture strength of 1.65 in {0001} orientation. Meanwhile, many dispersed secondary β-Mg17Al12 and Mg2Si phases were distributed inside the α-Mg matrix. It was confirmed that the SLM process introduced more grain recrystallization, inducing giant high-angle grain boundaries (HAGBs) and hindering the movement of dislocations, therefore forming dislocation strengthening while achieving grain refinement strengthening. Finally, three times the ultimate tensile strength of 313.7 MPa and higher microhardness of 96.4 HV than those of the as-cast state were obtained, verifying that the combined effect of grain refinement, solid solution strengthening and precipitation strengthening was responsible for the increased strength. This work provides new insight and a new approach to preparing AS41 magnesium alloy. [ABSTRACT FROM AUTHOR]

The slurry and sol‐gel methods were used to introduce SiC nanowires (SiCnws) into the SiCf/HfC‐SiC composites. The microstructures, ablation, and bending behaviors of the SiCnws modified composites prepared by the two methods were compared. The bending strengths of the modified composites obtained by introducing SiCnws by the slurry and sol‐gel methods were 224 ± 19 and 154 ± 14 MPa, respectively. The results showed that SiC fibers with chemical corrosion and thermal damage during the sol‐gel process decreased the bending strength of the SiCnws‐modified SiCf/HfC‐SiC composites. Meanwhile, the pyrolytic carbon interface accompanying corrosion damage in the sol‐gel process led to the degradation of interface function, which hindered the interface debonding and fiber sliding of the composites during the bending test. After ablation, the bending strengths of the two composites were 188 ± 19 and 50 ± 7 MPa, respectively. The bending strength retention of the modified composites fabricated by the slurry method (83.9%) was higher than that (32.5%) of the composites fabricated by the sol‐gel method after ablation. As the composites fabricated by the slurry method exhibited a good ablation resistance under the oxyacetylene flame (∼2350°C). [ABSTRACT FROM AUTHOR]

Stable interfaces between immiscible solvents are crucial for chemical synthesis and assembly, but interfaces between miscible solvents have been less explored. Here the authors report the spontaneous water-on-water spreading and self-assembly of polyelectrolyte membranes. An aqueous mixture solution containing poly(ethyleneimine) and poly(sodium 4-styrenesulfonate) spreads efficiently on acidic water, leading to the formation of hierarchically porous membranes. The reduced surface tension of the polyelectrolyte mixture solution drives the surface spreading, while the interfacial polyelectrolytes complexation triggered by the low pH of water mitigates water-in-water mixing. The synergy of surface tension and pH-dependent complexation represents a generic mechanism governing interfaces between miscible solvents for materials engineering, without the need for surfactants or sophisticated equipment. As a proof-of-concept, porous polyelectrolyte hybrid membranes are prepared by surface spreading, exhibiting exceptional solar thermal evaporation performance (2.8 kg/m2h) under 1-sun irradiation. Stable interfaces between immiscible solvents are crucial for chemical synthesis and assembly, but interfaces between miscible solvents have been less explored. Here the authors report the spontaneous water-on-water spreading and self-assembly of polyelectrolytes. [ABSTRACT FROM AUTHOR]

A comparative study on the influence of different manufacturing methods (selective laser melting and hot rolling) on the microstructure, mechanical and thermal behaviours of tungsten (W) was presented for the first time. The results indicated that the selective laser melting (SLM) W exhibited a finer grain sizes, a lower strength ductility, hardness and thermal conductivity compared to hot-rolled W. The main reason for this result was that the laser underwent rapid heating and cooling when it was used to melt W powder with high energy density, resulting in large internal stress in the sample after manufacturing. Subsequently, the internal stress was released, leading to the generation of micro-cracks at the grain boundaries, thereby affecting the performance of SLM W samples. In addition, the higher fraction of high-angle grain boundaries (HAGBs) of SLM W was found to be the key factor for intrinsic brittleness. Because the HAGBs are the preferred crack paths, which could promote crack propagation and decrease fracture energy. [ABSTRACT FROM AUTHOR]

In this article, polyvinylpyrrolidone (PVP) was used for the noncovalent modification on the surface of graphene. Compared with covalent modification, this method maintained the original structure of graphene layers, thereby maximizing the original properties of graphene. The π–π noncovalent bond was formed between PVP and graphene by X-ray photoelectron spectroscopy analysis, indicating that PVP successfully modified graphene. The thickness of graphene layer was measured by atomic force microscopy, which showed that the distance between graphene layers was increased by 5–6 nm, and the stability of the modified graphene in N, N -dimethylformamide was remarkably improved. The obtained composite coating by combination of the modified graphene and the epoxy resin was subjected to electrochemical impedance test to obtain the best anticorrosive effect of the coating with the graphene content of 0.3 wt%. The results showed that the addition of graphene to the epoxy resin could effectively improve the anticorrosive effect. Meanwhile, the good electrical conductivity allowed the electrons which lost from the substrate to led to air or saline rapidly, thereby reducing the combination of iron ions with oxygen and the generation of corrosion products (iron oxides). [ABSTRACT FROM AUTHOR]

Purpose: In the implementation of large-size additive manufacturing (AM), the large printing area can be established by using the tiled and fixed multiple printing heads or the single dynamic printing head moving in the x–y plane, which requires a layer decomposition after the mesh slicing to generate segmented infill areas. The data processing flow of these schemes is redundant and inefficient to some extent, especially for the processing of complex stereolithograph (STL) models. It is of great importance in improving the overall efficiency of large-size AM technics software by simplifying the redundant steps. This paper aims to address these issues. Design/methodology/approach: In this paper, a method of directly generating segmented layered infill areas is proposed for AM. Initially, a vertices–mesh hybrid representation of STL models is constructed based on a divide-and-conquer strategy. Then, a trimming–mapping procedure is performed on sliced contours acquired from partial surfaces. Finally, to link trimmed open contours and inside-signal square corners as segmented infill areas, a region-based open contour closing algorithm is carried out in virtue of the developed data structures. Findings: In virtue of the proposed approach, the segmented layered infill areas can be directly generated from STL models. Experimental results indicate that the approach brings us the good property of efficiency, especially for complex STL models. Practical implications: The proposed approach can generate segmented layered infill areas efficiently in some cases. Originality/value: The region-based layered infill area generation approach discussed here will be a supplement to current data process technologies in large-size AM, which is very suitable for parallel processing and enables us to improve the efficiency of large-size AM technics software. [ABSTRACT FROM AUTHOR]

Integrated sensor–actuators with exciting functionalities, such as action self‐sensing, position self‐sensing, posture self‐sensing, or active sensing, are promising for applications in biomedical device, human–machine interaction, intelligent self‐protection devices, and humanoid robots. Despite recent progress, it remains challenging to achieve a macroscopical integrated sensor–actuator in a material system with microstructures. To address this critical challenge, a 4D printing bioinspired microstructure strategy is reported to design a high‐performance integrated sensor–actuator capable of simultaneous actuation and sensation. Decoupled thermal stimulation and strain sensation is achieved by combining nanocarbon black/polylactic acid composites with bioinspired gradient microgap structures. As a result, printed integrated sensor–actuators can actively touch objects triggered by thermal stimulation and self‐sense the touching state through the resistance change. It is anticipated that the basic design principle underlying this behavior can be used to develop integrated sensor–actuators of various shapes and functionalities to meet desirable applications. [ABSTRACT FROM AUTHOR]

Ultra-sensitive cantilever transducers are always considered as a platform for the next generation of physical, chemical, and biological sensors. However, it is still a significant challenge to design artificial ultra-sensitive cantilever transducers, especially with a simple structure using a simple method and materials. A scorpion can sense extremely small air flow using only the simple cantilever-like trichobothria on its pedipalp. It can transduce micro airflow signals into deflection without bending. It was shown that the trichobothria in scorpion are mainly made up of two parts: the low-aspect-ratio elastic tissue and the high-aspect-ratio rigid hair shaft. More importantly, the aspect ratio and stiffness of the rigid hair shaft are extremely larger than those of the elastic tissue. Due to these special material and structural characteristics, the cantilever can achieve a high aspect ratio. Inspired by this principle, herein, a kind of deflection transducer with a high aspect ratio was designed. The results confirm that the designed transducer can also catch the stimulus signals by deflection, which can better concentrate stress. Moreover, this kind of transducer has higher sensitivity, easy fabrication, and low cost. Therefore, it is expected that this kind of new bioinspired sensor can be well-applied in many important engineering fields. [ABSTRACT FROM AUTHOR]

The crystallographic texture, thermal conductivity, and microhardness of the Cu-2.4Ni-0.7Si alloy processed by selective laser melting (SLM) were investigated. The SLM sample shows columnar grains with stronger (100) preferred orientation, and the content of high-angle grain boundaries (HAGBs) is 64.6%. It owns the lower microhardness of 89.73 Hv and the higher thermal conductivity of 187.83 W/m K. After heat treatment for 12 and 25 h, the microstructure of the samples changes from the coarser columnar grains to the smaller equiaxedlike grains with the HAGBs of 59.6% and 61.8%, which show (100), (101), and (111) orientations equally then exhibit stronger (101) and (111) preferred orientation. Moreover, the precipitates vary from Ni3Si with a size of 0.5 μm to Ni2Si with a size of 1 μm, hence resulting in higher microhardness of 180.02 and 170.03 Hv. Due to the precipitates, lower texture index and HAGBs' content that generate the more grain boundary scattering for electron and phonon transport lead to lower thermal conductivity of 161.57 and 177.83 W/m K. This study suggests that thermal conductivity and microhardness of the SLM Cu-Ni-Si alloy can be tailored by controlling suitable heat treatment condition. [ABSTRACT FROM AUTHOR]

Background: Diffusion tensor imaging (DTI) provides information about water molecule diffusion in spinal cord.Purpose: This study was aimed to investigate DTI changes in the different stages of compressive spinal cord induced by water-absorbing material implantation.Material and Methods: The spinal cord compression was administered over the fourth cervical vertebral level in rat. Rat models were divided into five subgroups according to compression stages: sham group, group A: three-day compression rat models; group B: 12-day compression rat models; group C: 20-day compression rat models; group D: 60-day compression rat models. DTI including fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in the compressive spinal cord were collected. The relationship between the Basso, Beattie, and Bresnahan (BBB) scores and DTI metrics was further explored.Results: Compared with the sham group, BBB scoring of rat model showed a decreased tendency from group A ( P < 0.05) to group B ( P < 0.05). Then the motor function of rat model hindlimbs was recovered in some degree from group C ( P < 0.05) to group D ( P < 0.05) but had significant motor defects when compared with the normal level ( P < 0.05). The DTI metrics results revealed that chronic spinal cord compression resulted in lower FA value and higher ADC value at the compressive spinal cord level assessed at all four time-points ( P < 0.05). DTI metrics also showed a close correlation with motor function ( P < 0.05).Conclusion: DTI is an optimal pre-clinical imaging tool to reflect locomotor performance and pathological status of compressive spinal cord epicenter in chronic spinal cord compression rat model. [ABSTRACT FROM AUTHOR]

The microstructural stabilities, softening resistance, and high-temperature tensile properties of the H13 hot-work tool steel by selective laser melting (SLM) were systematically studied. A series of tempering procedures were performed on the as-SLMed specimens. Afterwards, the mechanism of softening resistance behavior was discussed based on the XRD, SEM, EBSD observations, hardness measurements, and high-temperature tensile tests. It was found that the as-SLMed H13 consisted of α-iron and γ-iron. The carbide-stabilizing elements aggregated as the cell-like substructures for the rapid solidification of the SLM process. After the softening resistance treatment, the retained austenite transformed to ferrite and carbide mixtures. The cell-like substructures dissolved slowly into the matrix when the temperature was below 550 °C. These factors increased the hardness and retarded the softening of the material. When the temperature was 600 °C, the microstructural constituents transformed to soft ferrite and globular carbides, which lead to a considerable decrease of the hardness. Due to the grain refinement, solid solution strengthening, and residual stress, the as-SLMed H13 exhibited better mechanical properties than that of the wrought counterparts. [ABSTRACT FROM AUTHOR]

Purpose: A prognostic nomogram was applied to predict survival in osteosarcoma patients.Patients and methods: Data collected from 2,195 osteosarcoma patients in the Surveillance, Epidemiology, and End Results (SEER) database between 1983 and 2014 were analyzed. Independent prognostic factors were identified via univariate and multivariate Cox analyses. These were incorporated into a nomogram to predict 3- and 5-year overall survival (OS) and cancer-specific survival (CSS) rates. Internal and external data were used for validation. Concordance indices (C-indices) were used to estimate nomogram accuracy.Results: Patients were randomly assigned into a training cohort (n=1,098) or validation cohort (n=1,097). Age at diagnosis, tumor site, histology, tumor size, tumor stage, use of surgery, and tumor grade were identified as independent prognostic factors via univariate and multivariate Cox analyses (all P<0.05) and then included in the prognostic nomogram. C-indices for OS and CSS prediction in the training cohort were 0.763 (95% CI 0.761–0.764) and 0.764 (95% CI 0.762–0.765), respectively. C-indices for OS and CSS prediction in the external validation cohort were 0.739 (95% CI 0.737–0.740) and 0.740 (95% CI, 0.738–0.741), respectively. Calibration plots revealed excellent consistency between actual survival and nomogram prediction.Conclusion: Nomograms were constructed to predict OS and CSS for osteosarcoma patients in the SEER database. They provide accurate and individualized survival prediction. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to investigate critical genes in multiple sclerosis (MS) using microarray data from brain tissue in MS. Materials: The expression profile data set of MS (GSE38010) downloaded from the Gene Expression Omnibus database contained gene information from five plaque tissues from MS brains and two white matter tissues from healthy controls. An R package was applied to process these raw chip data. Gene Ontology (GO) functional analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and protein-protein interaction (PPI) network analysis were performed to investigate interactions between differentially expressed genes (DEGs) in MS brain tissues. Results: This study identified a total of 1065 DEGs, including 530 up-regulated genes and 535 down-regulated genes, in MS brain tissue samples compared to those in normal white matter tissue samples. GO and KEGG pathway enrichment analyses showed that the up-regulated DEGs were mainly related to neuron development, neuron projection morphogenesis and neuron differentiation. Furthermore, the down-regulated DEGs were largely related to axon ensheathment, ensheathment of neurons and nervous system development. Seven key genes were found as hub genes in the maintenance of the PPI network. Conclusion: Several key target genes and their GO and KEGG pathway enrichment identified in the present study may serve as feasible targets for MS therapies. [ABSTRACT FROM AUTHOR]

Purpose Selective laser melting (SLM) is an additive manufacturing process suitable for fabricating metal porous scaffolds. The unit cell topology is a significant factor that determines the mechanical property of porous scaffolds. Therefore, the purpose of this paper is to evaluate the effects of unit cell topology on the compression properties of porous Cobalt–chromium (Co-Cr) scaffolds fabricated by SLM using finite element (FE) and experimental measurement methods.Design/methodology/approach The Co-Cr alloy porous scaffolds constructed in four different topologies, i.e. cubic close packed (CCP), face-centered cubic (FCC), body-centered cubic (BCC) and spherical hollow cubic (SHC), were designed and fabricated via SLM process. FE simulations and compression tests were performed to evaluate the effects of unit cell topology on the compression properties of SLM-processed porous scaffolds.Findings The Mises stress predicted by FE simulations showed that different unit cell topologies resulted in distinct stress distributions on the bearing struts of scaffolds, whereas the unit cell size directly determined the stress value. Comparisons on the stress results for four topologies showed that the FCC unit cell has the minimum stress concentration due to its inclined bearing struts and horizontal arms. Simulations and experiments both indicated that the compression modulus and strengths of FCC, BCC, SHC, CCP scaffolds with the same cell size presented in a descending order. These distinct compression behaviors were correlated with the corresponding mechanics response on bearing struts. Two failure mechanisms, cracking and collapse, were found through the results of compression tests, and the influence of topological designs on the failure was analyzed and discussed. Finally, the cell initial response of the SLM-processed Co-Cr scaffold was tested through the in vitro cell culture experiment.Originality/value A focus and concern on the compression properties of SLM-processed porous scaffolds was presented from a new perspective of unit cell topology. It provides some new knowledge to the structure optimization of porous scaffolds for load-bearing bone implants. [ABSTRACT FROM AUTHOR]

Purpose Semi-crystalline polymers such as polyamide-12 can be used for selective laser sintering (SLS) to make near-fully dense plastic parts. At present, however, the types of semi-crystalline polymers suitable for SLS are critically limited. Therefore, the purpose of this paper is to investigate the processibility of a new kind of semi-crystalline polypropylene (PP) with low isotacticity for SLS process.Design/methodology/approach The SLS processibility of the PP powder, including particle size and shape, sintering window, degree of crystallinity and degradation temperature, was evaluated. Effects of the applied laser energy density on the surface micromorphology, density, tensile strength and thermal properties of SLS-built PP specimens were studied.Findings The results show that the PP powder has a nearly spherical shape, smooth surfaces, an appropriate average particle size of 63.6 μm, a broad sintering window of 21 oC and low crystalline degree of 30.4 per cent comparable to that of polyamide-12, a high degradation temperature of 381.8°C and low part bed temperature of 105°C, indicating a very good SLS processibility. The density and the tensile strength first increase with increasing laser energy density until they reach the maximum values of 0.831 g/cm3 and 19.9 MPa, respectively, at the laser energy density of 0.0458 J/mm2, and then decrease when the applied laser energy density continue to increase owing to the degradation of PP powders. The complex PP components have been manufactured by SLS using the optimum parameters, which are strong enough to be directly used as functional parts.Originality/value This paper provides a new knowledge for this field that low-isotacticity PPs exhibit good SLS processibility, therefore increasing material types and broadening the application of SLS technology. [ABSTRACT FROM AUTHOR]

Saliency detection models aiming to quantitatively predict human eye-attended locations in the visual field have been receiving increasing research interest in recent years. Unlike traditional methods that rely on hand-designed features and contrast inference mechanisms, this paper proposes a novel framework to learn saliency detection models from raw image data using deep networks. The proposed framework mainly consists of two learning stages. At the first learning stage, we develop a stacked denoising autoencoder (SDAE) model to learn robust, representative features from raw image data under an unsupervised manner. The second learning stage aims to jointly learn optimal mechanisms to capture the intrinsic mutual patterns as the feature contrast and to integrate them for final saliency prediction. Given the input of pairs of a center patch and its surrounding patches represented by the features learned at the first stage, a SDAE network is trained under the supervision of eye fixation labels, which achieves both contrast inference and contrast integration simultaneously. Experiments on three publically available eye tracking benchmarks and the comparisons with 16 state-of-the-art approaches demonstrate the effectiveness of the proposed framework. [ABSTRACT FROM PUBLISHER]

Selective laser melting (SLM) offers great possibilities to fabricate metal tools with a complex geometry, but there are limitations regarding some materials. This work focuses on the fabrication of AISI 420 stainless steel using SLM for the application of plastic injection mold. The melt characteristic of the powders was firstly concluded, and then the microstructure, phase composition, and hardness were characterized using scanning electron microscopy, X-ray diffraction, and Rockwell hardness test, respectively. The results showed that cellular microstructure was observed along the direction of the maximum heat flow. The proportion of the phases varies with the change of SLM processing parameters, which directly affects on the hardness of the parts. The relative density over 99% was obtained and the highest hardness presents 50.7 HRC, which meets the requirement of plastic injection molding application. [ABSTRACT FROM PUBLISHER]

Selective laser melting (SLM), as one of the additive manufacturing technologies, is widely investigated to fabricate metal parts. In SLM, parts are manufactured directly from powders in a layer-by-layer fashion; SLM also provides several advantages, such as production of complex parts with high three-dimensional accuracy, compared with other additive manufacturing technologies. Therefore, SLM can be applied in aeronautics, astronautics, medicine, and die and mould industry. However, this technique differs from traditional methods, such as casting and forging; for instance, the former greatly differs in terms of microstructure and properties of products. This paper summarizes relevant studies on metal material fabrication through SLM. Based on a work completed in Huazhong Univ. Sci Tech., Rapid Manuf. Center (HUST-RMC) and compared with characteristics described in other reported studies, microstructure, properties, dimensional accuracy, and application of SLM are presented. [ABSTRACT FROM AUTHOR]

Nickel-titanium alloys have been widely used in biomedical, aerospace and other fields due to their shape memory effect, superelastic effect, as well as biocompatible and elasto-thermal properties. Additive manufacturing (AM) technology can form complex and fine structures, which greatly expands the application range of Ni-Ti alloy. In this study, the development trend of additive manufactured Ni-Ti alloy was analyzed. Subsequently, the most widely used selective laser melting (SLM) process for forming Ni-Ti alloy was summarized. Especially, the relationship between Ni-Ti alloy materials, SLM processing parameters, microstructure and properties of Ni-Ti alloy formed by SLM was revealed. The research status of Ni-Ti alloy formed by wire arc additive manufacturing (WAAM), electron beam melting (EBM), directional energy dedication (DED), selective laser sintering (SLS) and other AM processes was briefly described, and its mechanical properties were emphatically expounded. Finally, several suggestions concerning Ni-Ti alloy material preparation, structure design, forming technology and forming equipment in the future were put forward in order to accelerate the engineering application process of additive manufactured Ni-Ti alloy. This study provides a useful reference for scientific research and engineering application of additive manufactured Ni-Ti alloys. [ABSTRACT FROM AUTHOR]

In this work Macadamia nutshell (MS) was used as filler in fused deposition modeling (FDM) of Poly (lactic acid) (PLA) composites filaments. Composites containing MS both treated and untreated with alkali and silane were investigated by means of Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), Thermogravimetry (TG), scanning electron microscopy (SEM). The results showed that the treated MS composites had better thermal stability. Furthermore, compression tests were carried out. The PLA with 10 wt% treated MS composite was found possessing the best mechanical properties which was almost equivalent to that of the pure PLA. Finally, porous scaffolds of PLA/10 wt% treated MS were fabricated. The scaffolds exhibited various porosities in range of 30–65%, interconnected holes in size of 0.3–0.5 mm, micro pores with dimension of 0.1–1 μm and 37.92–244.46 MPa of elastic modulus. Those values indicated that the FDM of PLA/MS composites have the potential to be used as weight lighter and structural parts. [ABSTRACT FROM AUTHOR]

To optimize the ablation resistance of ZrC coating, ZrC-SiC dispersive biphasic coating was prepared by chemical vapor co-deposition. The ablation resistances of the coatings were carried out by oxyacetylene flame tests. Compared with double-layered ZrC/SiC coating, the ablation resistance of ZrC-SiC coating was evaluated. On the basis of similar mass ablation rates of the two coatings, a new assistant method for characterizing the thermal protecting effect of coatings on carbon-carbon composites (C/C) composites was proposed. The thermal protecting ability of the coating was accurately reflected by the changes of hardness and elastic modulus of C/C substrate below the central region of ablated coatings before and after ablation. The ablation processes of two kinds of coatings were also discussed. The results showed that the hardness and elastic modulus of the C/C substrate protected by ZrC-SiC coating were higher than that of C/C coated with ZrC/SiC coating. The result convincingly illustrated the thermal protecting ability of ZrC-SiC coating was much better than that of ZrC/SiC coating, which attributed to the formation of Zr-Si-O glass. [ABSTRACT FROM AUTHOR]