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The advanced electron backscatter diffraction (EBSD) technique was used to examine the microstructure of a widely used A517GrQ low-carbon low-alloy steel after different heat treatments. Three distinguishable microstructures were studied. Slow cooling in the furnace after austenitization led to the formation of a granular structure that consisted of massive ferrite and randomly distributed M–A constituents. Medium rate cooling in air produced granular bainite that was composed of lath ferrite, and M–A constituents were distributed between the laths. Lath martensite was formed by fast cooling into ice brine. EBSD analysis revealed that, in one austenite grain, the massive ferrite in the granular structure and the lath ferrite in the granular bainite were predominately separated by high-angle boundaries, whilst the ferrite laths in the martensite were separated by low-angle boundaries. The specimens with granular bainite formed by medium rate cooling had higher strength (both yield strength and tensile strength), and also almost 5 times higher Charpy impact energy than that of the specimens containing granular structure obtained at the slow cooling. The strength of the specimens with lath martensite after quenching into ice brine was slightly higher than the granular bainite but were associated with much lower Charpy impact energy. The present work indicates that it is critical to control the cooling rate after austenitization in order to simultaneously achieve high strength and high toughness of low-carbon low-alloy steels.

Verteporfin (VP) is a specific inhibitor of yes-associated protein 1 (YAP1) that suppresses tumor progression by inhibiting YAP1 expression. The present study aimed to determine the inhibitory effect of VP on osteosarcoma and the underlying mechanism of its anticancer effects. Cell viability, cell cycle and apoptosis and cell migration and invasion were analyzed using the MTT assay, flow cytometry, wound healing assay and Transwell assay, respectively. Expressions of YAP1 and TEA domain transcription factor 1 (TEAD1) were measured using reverse transcription-quantitative PCR and western blotting, while their interaction was identified by the co-immunoprecipitation assay. In vivo mouse xenograft experiments were performed to evaluate the effect of VP on osteosarcoma growth. The results demonstrated that YAP1 and TEAD1 were highly expressed in osteosarcoma cells and tissues, whereas VP significantly downregulated the expression levels of YAP1 and TEAD1 in the osteosarcoma cell line Saos-2 compared with those in untreated control cells. In addition, compared with those in the control group, VP suppressed the viability, migration and invasion, induced cell cycle arrest in the G1 phase and promoted apoptosis in Saos-2 cells. In addition, VP inhibited mouse xenograft tumor growth in vivo compared with that observed in the control group. Notably, VP downregulated the levels of CYR61 expression in Saos-2 cells, whereas CYR61 overexpression mitigated the inhibitory effects of VP on osteosarcoma cells, as indicated by the increased viability and reduced apoptotic rates in Saos-2 cells overexpressing CYR61 compared with those in the control group. In summary, VP suppressed osteosarcoma by downregulating the expression of YAP1 and TEAD1. Additionally, CYR61 may mediate the effects of VP on osteosarcoma progression.

Influence maximization problem asks for a small subset of nodes in a social network that could maximize the spread of influence, which finds important applications in viral marketing. Most existing works focus on maximizing the influence of a single product or products that are in pure competition. However, a company usually produces different products to meet the needs of different people in reality. In this paper, we focus on the propagation of multiple products and propose multiple products independent cascade (MPIC) model, which allows each user to adopt multiple products. Aiming to maximize the overall profit across all products, we study the budgeted profit maximization (BPM) problem. To give a high-quality solution for BPM problem under the MPIC model, we present a modified greedy algorithm and derive the performance guarantee in doing so. Furthermore, we show that the two-phase profit maximization algorithm can not only handle the large-scale networks but also give the same approximation ratio as the modified greedy. In addition, we propose the cost performance update heuristics algorithm that has the results close to the above algorithms, and the running time is less than one ten-thousandth of the greedy. Our experiments on three real datasets verify the correctness and effectiveness of our methods, as well as the advantage of our methods against the traditional methods.

Grain refinement is one of the most effective approaches to improving mechanical properties, reducing anisotropy and hot-cracking of additively manufactured alloys. Recent studies have shown that the extreme solidification conditions associated with additive manufacturing (AM), including large thermal gradient and rapid cooling rate, result in the difference in nucleation and grain growth mechanisms between AM and conventional casting. Thus, it is necessary to re-consider the grain refinement mechanisms, particularly the role of solute during AM. The present work investigates the grain refining efficiencies of different solute additives (Si, Cu and Ni) and their integration with nucleants (LaB6 nanoparticles) in additively manufactured pure Al. It was found that, despite the rapid cooling during AM and nucleant inoculation, solute addition is essential for activating heterogeneous nucleation upon solidification to achieve high grain refining efficiency. However, the role of solute in grain refinement during AM cannot be readily interpreted by the classic grain growth restriction theory (Q value). This is attributed to the large thermal gradient in the melt pools during AM solidification, which significantly limits the development of constitutional supercooling. Alternatively, the role of solute can be better understood in terms of the lag in dendrite growth induced by solute rejection during solidification. This causes the difference between the actual dendrite growth and the theoretical pull rate, generating large thermal undercooling at the solidification front to elicit heterogeneous nucleation. This work sheds new light on the factors affecting grain refinement under rapid solidification.

Selective laser melting (SLM) has been successful in fabricating advanced engineering parts with high geometrical complexities. However, some metals or alloys with high strength, low weldability, and large freezing range, such as 7075 aluminium alloy, have low SLM-processability and are hard to be directly SLM-fabricated. Here, we proposed a novel strategy, combining substrate modification and inoculation treatment, to fabricate a crack-free and dense high-strength 7075 alloy using SLM at a broad processing window. Inoculation of the 7075 alloy powder with 1 wt% Ti submicron particles substantially refine the Al grains, effectively increasing the cracking resistance. Furthermore, the SLM substrate was modified, which allows integration of thermal insulation materials, such as vermiculite, to the substrate. As a result, the melt pool cooling rate and thermal gradient during solidification were significantly reduced. This directly led to a reduction in thermal stress within the melt pool. With combination of the substrate modification and Ti inoculation, crack-free, fine-equiaxed microstructure was obtained in the SLM-fabricated 7075 alloy that has the mechanical properties comparable to its wrought counterpart. This strategy can be implemented to SLM of other engineering alloys with low AM processability, providing a foundation for broadening industrial applications of SLM.

Intermetallic γ-TiAl alloy has been considered as a promising structural material for high temperature use, owing to their advantages such as low density, high creep strength and good toughness. However, due to its intrinsic brittleness, γ-TiAl alloy could not accommodate the high thermal stress generated by fast cooling during laser-based additive manufacturing (LAM) process, resulting in cracking and distortion. To surmount the roadblock of low processability associated with γ-TiAl alloy, grain refinement technology was integrated to LAM. In the present work, LaB6 nanoparticles were identified and experimentally verified, for the first time, as an effective inoculant for LAMed γ-TiAl alloy. The results showed that the grain size of the as-printed alloy drastically decreased from 39.81 ± 9.12 µm to 1.5 ± 2.07 µm through 0.5 wt% LaB6 addition. Accordingly, the microstructural morphology transformed from coarse near-lamellar colonies into equiaxed and fine grains. The LaB6 inoculation treatment not only led to the fabrication of crack-free alloy but concurrently increases in compressive yield strength, ultimate strength and strain to fracture by 29%, 12.4% and 61.9%, respectively. Such an enhanced performance is comparable with or even better than the γ-TiAl alloys produced using conventional processing techniques.

Selective laser melting (SLM) has been successful in fabricating advanced engineering parts with high geometrical complexities. However, some metals or alloys with high strength, low weldability, and large freezing range, such as 7075 aluminium alloy, have low SLM-processability and are hard to be directly SLM-fabricated. Here, we proposed a novel strategy, combining substrate modification and inoculation treatment, to fabricate a crack-free and dense high-strength 7075 alloy using SLM at a broad processing window. Inoculation of the 7075 alloy powder with 1 wt% Ti submicron particles substantially refine the Al grains, effectively increasing the cracking resistance. Furthermore, the SLM substrate was modified, which allows integration of thermal insulation materials, such as vermiculite, to the substrate. As a result, the melt pool cooling rate and thermal gradient during solidification were significantly reduced. This directly led to a reduction in thermal stress within the melt pool. With combination of the substrate modification and Ti inoculation, crack-free, fine-equiaxed microstructure was obtained in the SLM-fabricated 7075 alloy that has the mechanical properties comparable to its wrought counterpart. This strategy can be implemented to SLM of other engineering alloys with low AM processability, providing a foundation for broadening industrial applications of SLM.

Spinal cord injury (SCI) is a devastating disease, with a high rate of disability. In this meta-analysis, we aimed to comprehensively assess the efficacy and safety of mesenchymal stem cells (MSCs) in treating clinical SCI patients. We systematically searched the PUBMED, EMBASE, Chinese Biomedical (CBM), Web of Science and Cochrane databases using the strategy of combination of free-text words and MeSH terms. The indicators of the American Spinal Injury Association (ASIA) impairment scale (AIS)-grading improvement rate and adverse effects were displayed with an overall relative risk (RR). For the continuous variables of the ASIA motor score, light-touch score, pinprick score, activities of daily living (ADL) score, and residual urine volume, we used odds ratio (OR) to analyze the data. Eleven studies comprising 499 patients meeting all inclusion and exclusion criteria were included. No serious heterogeneity or publication bias was observed across each study. The results showed that significant improvements of total AIS grade (RR: 3.70; P < 0.001), AIS grade A (RR: 3.57; P < 0.001), ASIA sensory score (OR: 8.63; P < 0.001) and reduction of residual urine volume (OR: −36.37; P = 0.03) were observed in experimental group compared with control group. However, no significant differences of motor score (OR: 1.37, P = 0.19) and ADL score (OR: 2.61, P = 0.27) were observed between experimental and control groups. In addition, there were no serious and permanent adverse effects after cell transplantation. Cell transplantation with MSCs is effective and safe in improving the sensory and bladder functions of SCI patients.

Osteosarcoma (OS) is a common primary malignant bone tumor in young adolescents. About 30% of patients with OS have a recurrence, and the overall survival after OS recurrence is not good. In this study, we aimed to analyze and identify factors that influence prognosis after OS relapse. We retrieved the Gene Expression Omnibus data set and collected a series of transcriptome data with clinical information, including microRNA (miRNA) and messenger RNA (mRNA) expression profiles in recurrent OS. Upon comparison of the dysregulated genes of survival status in the recurrent OS samples, it was found that there were 268 differential expressed (DE) mRNAs and six DE miRNAs. These genes are related to pathways in cancer. We also predicted the interaction networks of these DE mRNAs and miRNAs. Further, we applied cibersort to estimate the proportion of immune cell types and we discovered that natural killer cells and macrophages have different abundance between good prognosis and poor prognosis. Our study indicates that for recurrent OS samples, there are several differences between these two groups, including gene expression and the status of immune activation. The immunity status is a candidate signature for disease prediction, prevention, and therapy choices.

Supplemental_materials for The Efficacy and Safety of Mesenchymal Stem Cell Transplantation for Spinal Cord Injury Patients: A Meta-Analysis and Systematic Review by Panfeng Xu, and Xianliang Yang in Cell Transplantation

Antioxidant activity of the ethanol extract of Erigeron breviscapus (EEEB) were studied by using neuron oxidative injury model induced by superoxide radical. EEEB at the dose of 10–140 μg/ml reduced significantly the lipid peroxidation levels and lactic dehydrogenase (LDH) release from neuron exposed to superoxide radical (generated by xanthine and xanthine oxidase). These results suggest that neuroprotective actions of EEEB may be due to its antioxidant or radical scavenging activity.

So far the energy saving potentials in refrigeration and air conditioning systems are the focuses of researchers all over the world. The all cold air distribution systems are being widely used due to the advantages of saving building space, less energy consumption in some given conditions and less initial cost, mostly in the residential or office buildings. The stratified air conditioning technology is adopted mainly for large space buildings to reduce the system energy consumption, normally at conventional supply air temperature. In this paper, with an example of large space building, the energy consumptions of four all outdoor air systems are calculated and compared from the view of the total annual primary energy consumption. The detailed analysis shows that comparing the conventional all outdoor air system for the whole indoor space or that with stratified air conditioning technology, the all cold outdoor air system with stratified air conditioning has the energy saving potentials. It will be promoted in the future application of HVAC systems in large space buildings.Copyright © 2008 by ASME

The aims of the present study were to investigate the regulatory function of scutellarin on production of nitric oxide (NO) as well as activities of constitutive NO synthase (cNOS) and inducible NO synthase (iNOS) in early stages of neuron damage induced by hydrogen peroxide. Direct detection of NO production was performed on primary cultures of living rat neuronal cells with an electrochemical sensor. Hydrogen peroxide significantly increased culture supernatant levels of NO, the total integral value of the defined areas (500-6500 sxpA) reached 3.68 x 10(6). Pre-treatment with scutellarin, caused the total integral value to decrease in a dose-dependent fashion (3.24 x 10(6), 2.15 x 10(6), 1.84 x 10(6) for groups 10, 50, and 100 uM scutellarin, respectively). After exposure to 2.0mM hydrogen peroxide for 2h, malondialdehyde (MDA) level, a marker of lipid peroxidation, was remarkably increased. The elevation can be suppressed by scutellarin. Hydrogen peroxide also caused significant loss of neuron viability. In comparison with the control group, scutellarin significant attenuated the loss. Results also showed that hydrogen peroxide increased activity of cNOS, which was markedly inhibited by scutellarin. However, exposure of neuronal cells to hydrogen peroxide did not lead to an increase in iNOS activity. In conclusion, our results suggest that NO production, which increased in early stages of neuron damage induced by hydrogen peroxide can be effectively inhibited by scutellarin. Moreover, our results indicate that increase in NO production is mediated by cNOS.

The antibacterial and antifungal properties of the ethanol extract of Erigeron breviscapus whole plant was evaluated. The extract showed a moderate antibacterial activity and a high antifungal activity.