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As main components of magnesia-based refractories, magnesia exhibits excellent properties such as high refractoriness and good basic slag corrosion resistance. However, magnesia produced from CaO containing cryptocrystalline magnesite has limited application owing to the low hydration resistance and poor thermal shock resistance (TSR). This work aimed to investigate the reinforcing effects of microscale monoclinic ZrO2 on free CaO containing magnesia for optimizing mechanical properties, TSR and hydration resistance. The results showed that adding ZrO2 could promote the removal of the open pores, strengthen the interface bonding between various grains and produce crack deflection, which improved flexural strength and fracture toughness. As a result, the TSR of the specimens was enhanced effectively due to increased strength and toughness and reduction in the thermal expansion coefficient. Besides, as the ZrO2 was introduced, hydration resistance of the specimens improved significantly, mainly attributing to the decrease in apparent porosity and elimination of the free CaO by forming CaZrO3 and cubic ZrO2 phases.

SiC porous ceramics (SPCs) are key functional medium materials, which are widely applied as porous burners. However, SPCs produced via the polyurethane sponge replica technique usually exhibit a randomly distributed cellular structure, leading to vulnerability and a low combustion efficiency for the porous burners. In this study, SPCs were structurally designed via novel 3D printed resin template technique; this endowed the SPCs with synergistically optimized strength and combustion characteristics. SPCs containing tetrakaidecahedron, octahedron and cubic cells were successfully prepared via SiC slurry coating and sintering in air. The cell parameters determined the strength and combustion properties of the SPCs. The SPCs containing cubic cells exhibited the largest strength and strain, because more struts were present parallel to the loading direction; this is more advantageous for stress bearing compared to those vertical to the loading direction. The tetrakaidecahedron cell facilitated the formation of a disturbance effect within the SPCs to a higher extent than the cubic and octahedron cells, thereby enhancing the heat exchange performance between the fluid and porous framework. Hence, the SPC with tetrakaidecahedron cells exhibited the best combustion properties, which resulted in the highest surface temperature and lowest pollution emission.

Glass-forming ability is a long-standing concern in the field of metallic glasses (MGs), which greatly limits their maximum casting size and extensive applications. In this work, we report an ultrasonic-assisted rapid cold welding of bulk MGs without using any additives. MGs with various compositions are welded together under a 20,000-Hz high-frequency ultrasonic vibration without losing their amorphous nature. The ultrasonic technology offers the advantages of rapid bonding (< 1 s) at low temperature (near room temperature) and low stress (< 1 MPa). According to the phenomenon observed in the experiment, the activated fresh atoms diffuse through the broken channel port under continuous rupture of the oxide layer, and the ultrasonic vibration accelerates the atomic-diffusion process. Finally, stable bonding of the MG interface is realized. This universal ultrasonic-assisted welding process can realize the composition design of dissimilar MGs as well as tuning of new materials with new performance.

Low-carbon MgO–C refractories are facing great challenges with severe thermal shock and slag corrosion in service. Here, a new approach, based on the incorporation of nano-sized ZrO2–Al2O3 composite powder, is proposed to enhance the thermal shock resistance and slag resistance of such refractories in this work. The results showed that addition of ZrO2–Al2O3 composite powder was helpful for improving their comprehensive performances. Particularly, the thermal shock resistance of the specimen containing 0.5 wt% composite powder was enhanced significantly which was related to the transformation toughening of zirconia and in-situ formation of more spinel phases in the matrix; also, the slag resistance of the corresponding specimen was significantly improved, which was attributed to the optimization of pore structure and formation of much thicker MgO dense layer.

Fused silica (SiO2) ceramic crucibles with α-Si3N4 coating are commonly used for smelting photovoltaic silicon (Si). However, SiO2 ceramics will inevitably undergo crystallization and large volume change during the high-temperature service, which will lead to crucible cracking and deteriorate the quality and yield of the Si ingot. In this work, α-Si3N4/SiO2 ceramics are fabricated by introducing α-Si3N4 into SiO2 ceramics to inhibit crystallization. The results show that the introduction of α-Si3N4 can effectively inhibit crystallization of SiO2 ceramics at temperature higher than 1450 °C. Only 5 wt% cristobalite form in SiO2 ceramic with 20 wt% α-Si3N4 (heated at 1550 °C for 30min). The crystallization activation energy of SiO2 ceramic containing 20 wt% α-Si3N4 increases by 2.27 times to 931.2kJ/mol compared with that of pure SiO2 ceramic (409.6kJ/mol). The inhibition crystallization effect and increased activation energy derive from the in-situ formation of O–Si–N chemical bond and physical isolation of SiO2 particles by α-Si3N4 powders.

Microstructures with hydrophobic surfaces have been widely used in industrial fields such as self-cleaning and drag reduction. With the aim of fabricating microplastic parts with a hydrophobic surface, the paper processed the mould insert with micro-groove arrays from 304 stainless-steel plate through low-speed wire electrical discharge machining (LS-WEDM). And the micro-groove arrays were designed to U shape with bottom radius of 70 μm and depth of 110 μm. Ultra-high molecular weight polyethylene (UHMWPE) powders were used as raw material to fabricate microplastic parts with hydrophobic surface structures by micro ultrasonic powder moulding (micro-UPM). The parameters of the micro-UPM process were obtained by the single-factor test method. Under the ultrasonic energy of 1200 J, welding pressure of 100 kPa and pressure holding time of 8 s, microplastic parts with well surface morphology (Ra =1.36 μm) and replication rate (97.76 %) were successfully fabricated. The surface contact angle of the microplastic part was 135.4°, which indicated well surface hydrophobicity.

SiC reticulated porous ceramics (RPCs), as the key functional components, are widely applied in field of molten-metal filtration. However, the hollow struts with triangular tips caused by burnt out of polymer foam reduced the strength of SiC RPCs, which limited their engineering application. Aiming to reveal the effects of template strut morphology on the mechanical performance of SiC RPCs, templates with triangular, square and circular cross sections were designed by additive manufacturing. Subsequently, SiC RPCs with varied strut structures were prepared by slurry immersion, followed by sintering at elevated temperature. The blunt of template strut improved the mechanical property of SiC RPCs, samples with circular hollow struts showed the highest crushing strength and strain than that of triangular and square hollow struts. From the results of simulation calculation, triangular hollow struts led to the significant stress concentration in the connection of struts and their middle parts, while the smaller stress uniformly distributed in the whole SiC skeleton as hollow struts became circle, thereby the improved mechanical properties were obtained in SiC RPCs.

Glucose metabolism is an essential process for energy production and cell survival for both normal and abnormal cellular metabolism. Several glucose transporter/solute carrier 2A (GLUT/SLC2A) superfamily members, including glucose transporter 1 (GLUT1), have been shown to mediate the cellular uptake of glucose in diverse cell types. GLUT1-mediated glucose uptake is a transient and rapid process; thus, the real-time monitoring of GLUT1 trafficking is pivotal for a better understanding of GLUT1 expression and GLUT1-dependent glucose uptake. In the present study, we established a rapid and effective method to visualize the trafficking of GLUT1 between the plasma membrane (PM) and endolysosomal system in live cells using an mCherry-EGFP-GLUT1 tandem fluorescence tracing system. We found that GLUT1 localized at the PM exhibited both red (mCherry) and green (EGFP) fluorescence (yellow when overlapping). However, a significant increase in red punctate fluorescence (mCherry is resistant to acidic pH), but not green fluorescence (EGFP is quenched by acidic pH), was observed upon glucose deprivation, indicating that the mCherry-EGFP-GLUT1 functional protein was trafficked to the acidic endolysosomal system. Besides, we were able to calculate the relative ratio of mCherry to EGFP by quantification of the translocation coefficient, which can be used as a readout for GLUT1 internalization and subsequent lysosomal degradation. Two mutants, mCherry-EGFP-GLUT1-S226D and mCherry-EGFP-GLUT1-ΔC4, were also constructed, which indirectly confirmed the specificity of mCherry-EGFP-GLUT1 for monitoring GLUT1 trafficking. By using a series of endosomal (Rab5, Rab7, and Rab11) and lysosomal markers, we were able to define a model of GLUT1 trafficking in live cells in which upon glucose deprivation, GLUT1 dissociates from the PM and experiences a pH gradient from 6.8–6.1 in the early endosomes to 6.0–4.8 in the late endosomes and finally pH 4.5 in lysosomes, which is appropriate for degradation. In addition, our proof-of-concept study indicated that the pmCherry-EGFP-GLUT1 tracing system can accurately reflect endogenous changes in GLUT1 in response to treatment with the small molecule, andrographolide. Since targeting GLUT1 expression and GLUT1-dependent glucose metabolism is a promising therapeutic strategy for diverse types of cancers and certain other glucose addiction diseases, our study herein indicates that pmCherry-EGFP-GLUT1 can be utilized as a biosensor for GLUT1-dependent functional studies and potential small molecule screening.

As the key component for porous media burner, the sufficient strength of SiC reticulated porous ceramics (RPCs) is necessary due to the scour of hot flue gas. However, SiC RPCs prepared with template replica method often exhibited serious oxidation and low strength when the foam was burnt out. In the present work, a sol-coated Al powder with high hydration resistance was introduced into the silicon carbide slurry to promote mullite formation in SiC skeleton, meanwhile reduce the SiC oxidation ratio of sample during the heat treatment. Firstly, the silica-sol coated Al with uniform silica-sol was successfully prepared via dip coating to improve the ability of hydration resistance of Al powder. Furthermore, sol-coated Al with spherical morphology improved rheological properties of silicon carbide slurry, including viscosity and rheological behavior. In addition, the evolution mechanism of sol-coated Al in SiC RPCs was revealed. The AlO2(g) and AlO(g) was first formed in the system, thus significantly reducing the SiC oxidation ratio in SiC RPC. The partial pressure of AlO(g) increased with the sintering temperature, the needle-shaped mullite formed at 1300 ○C when it dissolved in the microsilica, while lumpy mullite formed as SiC was the silica source in SiC RPCs. The addition of sol-coated Al was beneficial to optimize the microstructure of SiC skeleton, resulting in higher compressive strength of SiC RPCs.

Durability of cement mortar and concrete materials under sea water condition is always an important research topic. The objective of this work is to understand the mechanical properties of corroded cement mortar after high temperature, the cement mortar specimens after high temperature were placed in water and sodium sulfate solution, and then the uniaxial compression tests were carried out on the cement mortar specimens after corroded. Test results show that both the differences of compressive strength and strain at the peak stress after high temperature caused by high temperature, are relatively small when the specimens are eroded in water, and the differences are relatively high when the specimens are eroded in sodium sulfate solution. The compressive strength of the cement mortar specimens under normal temperature eroded in sodium sulfate solution is highest, and that eroded in water is lowest. The compressive strength of specimen after high temperature eroded in water is highest and that eroded in sodium sulfate solution is lowest. The strain at the peak stress of specimen, whether after high temperature or not, is highest when eroded in sodium sulfate solution, and that eroded in water is lowest. At present, there are few research results about the mechanical properties of concrete first after high temperature and then after sea water corrosion. The work in this paper can enrich the results in this area.

Tool wear is a prominent problem during drilling of carbon-fibre-reinforced polymer (CFRP). This paper investigated the tribological behaviors and wear mechanism of CFRP against tungsten carbide under dry friction condition. The influence of load, temperature and sliding velocity on friction coefficient were studied. The wear morphology was detected and showed the inhomogeneity and anisotropy of CFRP have important influence on wear characteristics. Moreover, running-in process will have a positive influence on the subsequent friction process under certain conditions. A novel method which adopted pre running-in was thus proposed to improve tool life, and the effectiveness was verified by drilling tests. Present work reveals the wear mechanism of CFRP against tungsten carbide, and provides a new idea for reducing tool wear.

Background Child-Turcotte-Pugh (CTP) score extensively used to assess hepatic function, predicting postoperative outcome of hepatocellular carcinoma (HCC) patients. Lately, the albumin–bilirubin (ALBI) grade has been identified to be a predictor of overall survival of HCC patients. In this investigation, we compared the pre-SBRT ALBI and CTP scores with the prognosis of patients with HCC. Methods This cohort study included 594 HCC patients who treated with SBRT. Overall survival (OS) rates were measured from treatment date to death date or last follow-up. We compared ALBI score with the CTP score in predicting long-term survival. Results The average follow-up time was 21 months (1 to 82 months). The CTP and ALBI ratings have discriminatory for long-term survival across the groups. CTP class was significantly related to OS, with a median OS of 29.9 months in CTP-A, 11.5 in CTP-B (P 0.05). Conclusions To assess liver dysfunction in HCC patients before SBRT, traditional CTP classification is a necessary but imperfect tool for assessing HCC liver injury. The ALBI score is a more objective, discriminatory and evidence-based approach in CTP-A groups, and need to be validated in CTP ≥ B7 class.

Kai Xin San (KXS, containing ginseng, hoelen, polygala, and acorus), a traditional Chinese herbal compound, has been found to regulate cognitive dysfunction; however, its mechanism of action is still unclear. In this study, 72 specific-pathogen-free male Kunming mice aged 8 weeks were randomly divided into a vehicle control group, scopolamine group, low-dose KXS group, moderate-dose KXS group, high-dose KXS group, and positive control group. Except for the vehicle control group and scopolamine groups (which received physiological saline), the doses of KXS (0.7, 1.4 and 2.8 g/kg per day) and donepezil (3 mg/kg per day) were gastrointestinally administered once daily for 2 weeks. On day 8 after intragastric treatment, the behavioral tests were carried out. Scopolamine group and intervention groups received scopolamine 3 mg/kg per day through intraperitoneal injection. The effects of KXS on spatial learning and memory, pathological changes of brain tissue, expression of apoptosis factors, oxidative stress injury factors, synapse-associated protein, and cholinergic neurotransmitter were measured. The results confirmed the following. (1) KXS shortened the escape latency and increased residence time in the target quadrant and the number of platform crossings in the Morris water maze. (2) KXS increased the percentage of alternations between the labyrinth arms in the mice of KXS groups in the Y-maze. (3) Nissl and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining revealed that KXS promoted the production of Nissl bodies and inhibited the formation of apoptotic bodies. (4) Western blot assay showed that KXS up-regulated the expression of anti-apoptotic protein Bcl-2 and inhibited the expression of pro-apoptotic protein Bax. KXS up-regulated the expression of postsynaptic density 95, synaptophysin, and brain-derived neurotrophic factor in the cerebral cortex and hippocampus. (5) KXS increased the level and activity of choline acetyltransferase, acetylcholine, superoxide dismutase, and glutathione peroxidase, and reduced the level and activity of acetyl cholinesterase, reactive oxygen species, and malondialdehyde through acting on the cholinergic system and reducing oxidative stress damage. These results indicate that KXS plays a neuroprotective role and improves cognitive function through reducing apoptosis and oxidative stress, and regulating synapse-associated protein and cholinergic neurotransmitters.

Flexible forming process-polymer powder medium based flexible forming (PPFF) is presented in this research. The metallic bipolar plate (BPP) for a proton exchange membrane (PEM) fuel cell, with a micro-scale flow channel on its surface, is formed using rigid die forming and PPFF process, respectively. Pure copper C1100 (with a thickness of 0.1 mm), annealed at 450 °C for 1 h in vacuum condition, is selected as blank material. The forming experiments are carried out at room temperature in dry friction condition. By comparing the limit forming depth, fracture topography, section wall thickness distribution and surface forming quality of micro-scale flow channels between rigid die forming and PPFF process, it reveals that PPFF process could be developed as a feasible technique to fabricate the bipolar plates of PEM fuel cells. The PPFF process has the following advantages: greater forming depth, more uniform wall thickness distribution, and low cost of the die.

Constructing regular micro-structures with certain geometric characteristics on the surface of the polymer part can obtain some specific functions. Micro ultrasonic powder molding (micro-UPM) is an efficient processing technique for the fabrication of well-filled micro-structured Polypropylene (PP) parts. The micro-structure array on the surface of the core insert was obtained by low speed wire electrical discharge machining (WEDM-LS). PP polymer surfaces with micro-structured patterns were successfully replicated from the core insert surface after micro-UPM. By studying the detailed topography characterizations of micro-structured PP parts, the effects of processing parameters (ultrasonic energy, welding pressure and holding time) on the micro-structured filling show that when PP polymer was formed under the conditions of 1000 J, 115 kPa and 8 s during micro-UPM, well-filled micro-structured parts can be obtained. Besides, without low surface energy coating modification, the water contact angles (WCAs) of micro-structured PP parts increased from 85.3&deg, to 146.8&deg, indicating that the wettability of the surface can be changed by replicating the micro-structure on PP parts after micro-UPM.

Background: Several epidemiological studies have been performed to evaluate the association of dietary intake of vitamin C-oriented foods (DIVCF) with risk of fracture and bone mineral density (BMD) loss, but the results remain controversial. Therefore, we conducted a systematic meta-analysis to assess this correlation. Methods: We searched EmBase, PubMed, Web of Science, and the Chinese database CNKI for relevant articles published up to August 2019. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using the random- or fixed-effects model. Discrepancies were resolved by consultation with a third expert. Results: A total of 13 eligible articles (including 17 studies) with 19,484 subjects were identified for the present meta-analysis. The pooled RR of hip fracture for the highest vs. lowest category was 0.66 (95% CI, 0.47–0.94) for DIVCF, i.e., people with a greater frequency of Vitamin C uptake had a 34% (95% CI, 6%−53%) lower prevalence of hip fracture. In subgroup analyses stratified by study design, gender, and age, the negative associations were statistically significant. Furthermore, the statistical analysis of the association between DIVCF and risk of osteoporosis (RR, 0.66; 95% CI, 0.48–0.92), BMD at the lumbar spine (pooled r, 0.15; 95% CI, 0.09–0.23), and BMD at the femoral neck (pooled r, 0.20; 95% CI, 0.11–0.34) showed beneficial effects of DIVCF. Conclusion: Our meta-analysis indicates that DIVCF is negatively associated with the risk of hip fracture, osteoporosis, and BMD loss, suggesting that DIVCF decreases the risk of hip fracture, osteoporosis, and BMD loss.

3D-reticulated porous (3D-RP) SiC ceramic was fabricated by polymer sponge replica technique with SiC ceramic slurry (77 wt% solid content). Furthermore, pure alumina slurry and alumina slu...

To investigate the effects of femtosecond laser ablation on the surface morphology and microstructure of ultrafine-grained copper, point, single-line scanning, and area scanning ablation of ultrafine-grained and coarse-grained copper were performed at room temperature. The ablation threshold gradually increased and materials processing became more difficult with decreasing grain size. In addition, the ablation depth and width of the channels formed by single-line scanning ablation gradually increased with increasing grain size for the same laser pulse energy. The microhardness of the ablated specimens was also evaluated as a function of laser pulse energy using area scanning ablation. The microhardness difference before and after ablation increased with decreasing grain size for the same laser pulse energy. In addition, the microhardness after ablation gradually decreased with increasing laser pulse energy for the ultrafine-grained specimens. However, for the coarse-grained copper specimens, no clear changes of the microhardness were observed after ablation with varying laser pulse energies. The grain sizes of the ultrafine-grained specimens were also surveyed as a function of laser pulse energy using electron backscattered diffraction (EBSD). The heat generated by laser ablation caused recrystallization and grain growth of the ultrafine-grained copper; moreover, the grain size gradually increased with increasing pulse energy. In contrast, no obvious changes in grain size were observed for the coarse-grained copper specimens with increasing pulse energy.

Water disinfection would result in unintended formation of halogenated disinfection by-products (DBPs) which pose potential harm to human health. In present work, Fe78Si9B13 amorphous ribbons (Fe-Si-BAR) showed excellent catalytic degradation performance towards an aromatic DBP, 3,5-dichlorosalicylic acid (3,5-DiClSA) by Fenton-like reaction. The catalytic degradation performances of Fe-Si-BAR, Fe78Si9B13 crystalline ribbons (Fe-Si-BCR) and iron powders towards 3,5-DiClSA were compared, and Fe-Si-BAR (0.0166 min−1) showed the fastest degradation rate. The faster surface mobility of Fe-Si-BAR, which made it easy for Fe2+ to be oxidized by H2O2, facilitated the degradation process. High-valent iron of FeIV could be generated which accounted for degradation of 3,5-DiClSA. The Fe-Si-BAR also showed better and better catalytic performance in 10 reuse cycles. Besides, the cytotoxicity tests indicated that the overall toxicity level of 3,5-DiClSA was declined by 88.1 % after degradation by Fe-Si-BAR. Our results showed that Fe-Si-BAR is a promising catalyst for the degradation of aromatic DBPs.

Silicon carbide reticulated porous ceramics (SiC RPCs) were fabricated by polymer replica technique. The effects of nitride whisker template on the growth of mullite, the strut structure and mechanical properties of SiC RPCs were investigated. Prepolyurethane (PU) open-cell sponge was first coated by SiC slurry consisting of SiC, reactive Al 2 O 3 , microsilica and Si powder, then it was nitridized at 1400 °C in a flowing N 2 atmosphere to prepare SiC preforms. Subsequently, these preforms were treated by vacuum infiltration of alumina slurry and fired at 1450 °C in air. The results showed that Si 2 N 2 O whiskers grew on the surface and in the matrix of SiC preforms after nitridation. The diameter of struts in SiC RPCs increased after vacuum infiltration process because alumina slurry was easily adhered by the surface nitride whiskers. In addition, such whiskers inside the strut of SiC preforms acted as the template to promote the growth of column-liked mullite in SiC RPCs. The mechanical properties and thermal shock resistance of SiC RPCs were greatly improved due to the special interfacial characteristics of multi-layered struts as well as better interlocked column-liked mullite in SiC skeleton.

A hybrid process combining ultrasonic injection molding and electrical discharge machining was proposed to realize the economic, high-precision, and environmental-friendliness production of glass fiber reinforced polypropylene microstructured parts. First, the prism array microstructures were processed on tungsten carbide-cobalt (WC-8 wt% Co) substrate by low-speed wire electrical discharge machining and used as the mold core. Then, the glass fiber reinforced polypropylene composite (GF/PP) was melted under ultrasonic vibration, and the surface microstructure of the mold core was replicated. The experimental results show that this method can efficiently and accurately manufacture microstructured parts, and the microstructure has a high replication rate up to 95.5%. By replicating the microstructure, the surface contact angle of GF/PP parts increased from 57.1° to 134.9°, and the wettability changed from hydrophilicity to hydrophobicity. The mechanical properties test results show that the GF/PP parts fabricated by ultrasonic injection molding had excellent mechanical properties, and the 30% GF/PP parts show the highest tensile strength of 56.9 MPa. This work provides a new option for fabricating fiber reinforced composite parts.

Silicon carbide reticulated porous ceramics (SiC RPCs) with multi-layered struts were fabricated by polymer replica technique with SiC slurry, followed by infiltrating alumina slurries containing andalusite under vacuum condition. The effects of andalusite addition on the microstructure and mechanical properties of SiC RPCs were investigated, also the residual stress within the multi-layered strut was predicted. Theoretical calculations showed that the residual tensile stress generated in the outer layer of SiC RPCs because of its larger thermal expansion coefficient of infiltration slurry than that of SiC slurry at elevated temperature. Furthermore, the addition of andalusite reduced the thermal expansion coefficient and Young's modulus of infiltration slurries, thereby significantly reducing the residual stress of the outer layer in multi-layered struts. The reduced residual tensile stress within the outer layer was beneficial to eliminate surface cracks on the struts, thus improving the mechanical properties and thermal shock resistance of SiC RPCs.

Silicon carbide reticulated porous ceramics (SiC RPCs) with three-layered struts were fabricated by polymer replica method, followed by infiltrating alumina slurries containing silicon (slurry-Si) and andalusite (slurry-An), respectively. The effects of composition of infiltration slurries on the strut structure, mechanical properties and thermal shock resistance of SiC RPCs were investigated. The results showed that the SiC RPCs infiltrated with slurry-Si and slurry-An exhibited better mechanical properties and thermal shock resistance in comparison with those of alumina slurry infiltration, even obtained the considerable strength at 1300 °C. In slurry-Si, silicon was oxidized into SiO2 in the temperature range from 1300 °C to 1400 °C and it reacted with Al2O3 into mullite phase at 1450 °C. Meantime, the addition of silicon in slurry-Si could reduce SiC oxidation of SiC RPCs during firing process in contrast with alumina slurry. With regard to slurry-An, andalusite started to transform into mullite phase at 1300 °C and the secondary mullitization occurred at 1450 °C. The enhanced mechanical properties and thermal shock resistance of SiC RPCs infiltrated alumina slurries containing silicon and andalusite were attributed to the optimized microstructure and the triangular zone (inner layer of strut) with mullite bonded corundum via reaction sintering. In addition, the generation of residual compressive stress together with better interlocked needle-like mullite led to the crack-deflection in SiC skeleton, thus improving the thermal shock resistance of obtained SiC RPCs.

The aim of the present study was to determine the radiosensitization effect of the combination of curcumin and cisplatin on non-small cell lung cancer (NSCLC) A549 cells. Cell viability was analyzed using the MTT assay following treatment with different concentrations of curcumin and cisplatin for 24~72 h. Survival fraction (SF) value of the treatment groups (single irradiation, curcumin + irradiation, cisplatin + irradiation, and curcumin + cisplatin + irradiation) treated with different doses of X-ray radiation were evaluated using colony formation assay, according to a multi-target single-hit model. Migration and invasion as well as the levels of epidermal growth factor receptor (EGFR) protein following 24 h were detected by scratch wound assay, Matrigel assay and western blot analysis, respectively. The results of the present study demonstrated that the viability of the cells decreased after being treated by curcumin, and the inhibitory effect was dose and time-dependent as the concentration of curcumin increased from 10 to 200 µmol/l (P

Micro components processed by injection molding still have a defect of bad precision and short life. A Zr- based metallic glass was reported for injection mold insert which can solve the problem well. The microstructure of metallic glass mold insert can be fabricated by wire electrical discharge machining-low speed (WEDM-LS), WEDM-LS has higher machining accuracy than WEDM-high speed, and X-ray diffraction curves show that the processed sample still retained better amorphous characteristic, afterward, time-temperature-transformation diagram shows metallic glass has a long service life in production. Finally, under the observe of scanning electron microscope, it is found that the products after injection molding not only completely replicates the structure on metallic glass but also have a better surface morphology. These experiments show that processing a sophisticated and durable Zr-based metallic glass mold by WEDM-LS is good for getting micro structure injection of polymers. It also provides a good mold material and machining method for injection industry.

Silicon carbide reticulated porous ceramics (SiC RPCs) with multi-layered struts were fabricated at 1450 °C by polymer sponge replica technique, followed by vacuum infiltration. The effect of additives (polycarboxylate, ammonium lignosulfonate and sodium carboxymethyl-cellulose) on the rheological behavior of silicon carbide slurry was firstly investigated, and then the slurry was coated on polyurethane open-cell sponge template. Furthermore, alumina slurry was adopted to fill up the hollow struts in vacuum infiltration process after the coated sponge was pre-treated at 850 °C. The results showed that the coating thickness on the struts and the microstructure in SiC RPCs were closely associated with the solid content of alumina slurry during vacuum infiltration. The typical multi-layered strut of SiC RPCs could be achieved after the infiltration of an alumina slurry containing 77 wt% solid content. The compressive strength and thermal shock resistance of the infiltrated specimens were significantly improved in comparison with those of non-infiltrated ones. The improvement was attributed to the in-situ formation of reaction-bonded multilayer struts in SiC RPCs, which were characterized by the exterior coating of aluminosilicate-corundum, middle part of mullite bonded SiC and interior zone of corundum.

Fe-based amorphous alloys have been proved to exhibit excellent degradation properties for the removal of copper ions from simulated wastewater. Compared with crystalline iron, amorphous alloy has higher removal efficiency, lower reaction activation energy and high corrosion current density owing to its unique surface mobility. The copper ion can be reduced to less than 0.5 or 1 ppm at different initial concentrations. Even at a lower concentration of copper ions, it also exhibits better performance. In comparison, the concentration of the copper ion would be higher than the prescribed discharge standard if the wastewater was treated by crystalline iron. This work provides a potential application of Fe - based amorphous in the removal of heavy metal ions from wastewater.

Purpose – This paper aims to present the main factors affecting the mechanical drilling of the printed circuit board (PCB for short) micro-holes and method of micro-ultrasonic powder molding (micro-UPM for short) by utilizing PCB micro-hole array. Design/methodology/approach – To optimize the drilling process, the paper proposes the on-line monitoring methods for the drilling process including drilling force, drilling temperature, high-speed photography and vibration signals. Taking 0.10 and 0.15 mm micro-drilling as examples, the paper analyzes the drilling process of ultra-small micro-holes. Finally, by taking the PCBs with 0.10 and 0.15 mm micro-hole arrays as the micro-cavity inserts, utilizing ultra-high-molecule weight polyethylene powder with the average particle size of about 150 μm as raw material, two sizes of micro-cylinder array polymer parts are fabricated through micro-UPM process. Findings – PCB micro-cavity inserts with micro-hole arrays fabricated by mechanical drilling has the advantages of low costs, high efficiency and good consistency. Taking 0.10 and 0.15 mm micro-drilling as examples, it is found that the both measured apertures are about 10.0 μm more than the diameter of the micro-drill bits on average. The average diameter of the micro-cylinders by micro-UPM process is smaller than that of the micro-hole with the same specification, while the value of the roughness of the cylinder surface is more than that of the hole-wall surface with the same specification. Originality/value – This paper describes the challenges and the developments of mechanical drilling and by using PCB micro-cavity inserts with micro-hole arrays fabricated by mechanical drilling, two different micro-cylinder array polymer parts are successfully made and thus the application area of PCB micro-drilling is broadened.

The observations of grain-boundary segregation of Bi in Cu bicrystals were analyzed. According to equilibrium grain boundary segregation (EGS) model and non-equilibrium grain-boundary segregation (NGS) model, respectively, the segregation kinetics of isothermal annealing at 500 °C and that of isochronal annealing for 24 h of Bi in Cu bicrystals were investigated. By qualitative analysis and quantitative analysis, it is concluded that the grain-boundary segregation of Bi agrees well with the theory of NGS. Based on the kinetics model of NGS, some parameters that are useful to predicting and controlling the Bi-induced embrittlement in Cu alloys are calculated as follows: the diffusion coefficient of Bi-vacancy complexes D c =7.8×10 −5 exp[–1.46/( kT )]; the apparent diffusion coefficient of Bi atoms D i A =7.66×10 at + b exp[–1.76/( kT )], where a =8.45×10 −8 and b =–13.37.

Aimed at microplastic parts molding, we use a novel method of micro-ultrasonic powder molding (micro-UPM) on polypropylene (PP) microplastic parts and investigate the experimental process in detail. Firstly, the experimental results show that the temperature is maximum on the top outer edges of plastic parts and minimum on the bottom center. Then, the effects of experimental process parameters on plastic flashes are studied. The results show that under the same pressure, the flash thickness gradually thins with increased ultrasonic time. The ultrasonic time for the flashes to be automatically separated from the matrix of microplastic parts is obviously shortens with increased pressure. Finally, the tests on thermal properties, morphology, and mechanical properties of microplastic parts are also conducted. The results show that the melting point and crystallinity of microplastic parts produced by micro-UPM are higher than those of raw materials. The organizational structure shows no obvious “skin–core” structure, and its crystal form is α crystal form, which is the most common type of polypropylene. With increased ultrasonic time, the tensile strength and elongation at break of samples both have a trend of rise followed by drop before and after annealing. An ultrasonic time that is too long can lead to the degradation of materials.

PurposeThe purpose of this paper is to present a method for ultrasonically molding polymer powder in a micro plastic part mold. In the method, a printed circuit board (PCB) in which micro‐hole arrays are drilled is used as a micro cavity insert. With the utilization of ultrasonic vibration, the polymer powder, which is prefilled and compacted in a micro cavity, mutually generates great sliding friction heat so as to be rapidly plasticized and molded.Design/methodology/approachMicro carbide drill bits of which the diameters are 100.0 μm, 150.0 μm and 200.0 μm, respectively, are used for drilling the PCB to form a micro‐hole array insert. Next, two kinds of various ultra‐high molecule weight polyethylene (UHMW‐PE) powder with various grain diameters are directly filled into a charging barrel and a mold cavity with the micro‐hole array insert. Proper process parameters are set on ultrasonic plasticizing and molding equipment so that a molding test can be performed. The melt of UHMW‐PE can be rapidly filled into the cavity. Finally, micro‐column array plastic parts are successfully prepared.FindingsThe micro‐hole array PCB is a mold insert which is quite applicable for the ultrasonic molding of the powder in the mold. When a molding material is the coarse UHMW‐PE powder with the grain diameter of about 350 μm, the diameter replication rates of the micro‐column array plastic parts become good in order with the increased micro‐hole diameter of the PCB. When the fine UHMW‐PE powder with the grain diameter of about 80 μm is adopted, the diameter replication rates of the micro‐column array plastic parts become good in order with the decreased micro‐hole diameter of the PCB.Originality/valueIn this paper, the micro‐column array plastic parts with good replicability are successfully prepared by a technique for ultrasonically plasticizing and molding in the cavity. The technique can be applied to the fields of medical treatment, communication, optics, chemistry and so on, such as biological micro needle arrays, micro biological chips, optical memories, and micro chemical reaction chips.

The work proposed a novel thermoplastic forming approach–the ultrasonic beating forming (UBF) method for bulk metallic glasses (BMGs) in present work. The rapid forming approach can finish the thermoplastic forming of BMGs in less than one second, avoiding the time-dependent crystallization and oxidation to the most extent. Besides, the UBF is also proved to be competent in the fabrication of structures with the length scale ranging from macro scale to nano scale. Our results propose a novel route for the thermoplastic forming of BMGs and have promising applications in the rapid fabrication of macro to nano scale products and devices.

To explore further the influencing of mechanical effects on laser machining in the liquid, in the process of great-energy and short-pulsed laser irradiating matter in the liquid, the experiments of 248 nm laser etching n -Si under water were carried out. The removal mechanism of brittle material etched by mechanical effects, which is induced during high-energy and short-pulsed laser machining in the liquid, was discussed. In the paper, the approximate mechanics model of indentation fracture was used to analyze the mechanical effects for removing brittle materials of silicon when laser machining in the liquid. Based on this, a theoretical model of material removal rate was proposed; the experiment of laser machining under water was adopted to validate the model. The experimental results indicate that the removal rate of brittle material caused by shock forces is relatively great.

Metallic glasses (MGs) are considered as ideal materials for miniature fabrication because of their excellent thermoplastic forming ability in the supercooled liquid region. We show that Pd-based MG micro grooves, which are essential for microdluidic devices, can be prepared by a highly efficient and precise fabrication method. The scanning electron microscope observation and surface profiler measurement show that the MG micro grooves have superior dimensional accuracy. The excellent corrosion resistance of MGs compared with silicon, which is the conventional microfluidic device material, is also proved by the weight-loss corrosion method. Our results indicate that MG can be a promising candidate material for the fabrication of microfluidic devices and may have broad applications in the biomedical areas.

The transmittance and reflectance of cuprous oxide (Cu2O) thin film deposited on quartz substrate were measured by a spectrophotometer. Use the optical dielectric model combining the Forouhi–Bloomer model with modified Drude model (FBM+MDM), the optical constants, as well as the thickness of Cu2O film were attained from its measured transmittance data. Moreover, by means of the TFCalc software, the reflectance and transmittance were calculated conversely from the optical constants (n, k) and the thickness of the Cu2O film. It was found that the calculated reflectance and transmittance were in good agreement with the measured ones. So the optical dielectric model, namely FBM+MDM, is suitable for Cu2O thin film.

In this study, using high-speed mechanical drilling on printed circuit boards (PCBs) with two micro carbide drill bits with diameters of 0.15 mm and 0.20 mm, two different PCB micro-cylinder array inserts are fabricated using the micro-ultrasonic powder moulding (micro-UPM) process. According to the temperature curves recorded by a measurement module, when viscoelastic heating dominated, the temperature increasing rate was about three times the rate when interfacial friction heating dominated. From the differential scanning calorimetry and nanoindentation test results, if the ultra-high molecule weight polyethylene (UHMWPE) powder was not preheated, then the micro-cylinder array polymer parts generally consisted of nascent and melt-recrystallised phases as a whole. However, when the micro-cavity and compressed UHMWPE powder grew from room temperature of 28 °C to 85 °C, the two-phase structure gradually developed into a single melt-recrystallised phase. According to single-crystal x-ray diffraction test results, the crystallinity of the base region of the micro-UPM cylinder array part is higher than that of the micro-cylinder region, whereas the grain size of the (1 1 0) crystal surface is larger than that of the (2 0 0) crystal surface.

Apelin receptor (APJ) deficiency has been reported to be preventive against atherosclerosis. However, the mechanism of this effect remains unknown. In this study, quantitative real-time RT-PCR, Western blotting and ELISA analyses revealed a significant increase in the expression of intercellular adhesion molecule-1(ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1 (MCP-1) in human umbilical vein endothelial cells (HUVECs) treated with apelin. Inhibitors of cellular signal transduction molecules were used to demonstrate involvement of nuclear factor kappa-B (NF-κB) and c-Jun N-terminal kinase (JNK) pathways in apelin–APJ-induced activation of adhesion molecules and chemokines. Inhibition of APJ expression by RNA interference abrogated apelin-induced expression of adhesion molecules and chemokines and apelin-stimulated cellular signal transduction in HUVECs. The apelin–APJ system in endothelial cells is involved in the expression of adhesion molecules and chemokines, which are important for the initiation of endothelial inflammation-related atherosclerosis. Therefore, apelin–APJ and the cell signaling pathways activated by this system in endothelial cells may represent targets for therapy of atherosclerosis.

The behaviour of boron atoms in Ni 3 Al and its effect on strength properties has been systematically studied by means of metallography, X-ray diffraction, transmission electron microscopy, ion probe analysis, positron annihilation and atom probe-field ion microscopy. Results show that the yield strength of poly- and monocrystalline Ni 3 Al at 20 and 800°C increases with increasing boron content, mainly because of solid solution strengthening by boron atoms which occupy interstitial sites in the crystal lattice of Ni 3 Al. Its effect of filling the void-type defect and increasing the bond energy of nearest-neighbour pairs of NiNi and AlAl have also made some contributions to the strength properties. When the boron content exceeds its solubility in Ni 3 Al and reaches 2.22 at.%, the strength decreases markedly because of the formation of a boride eutectic which promotes crack nucleation and propagation. The rupture life of polycrystalline Ni 3 Al increases with increasing boron content, an important cause of which is the grain boundary strengthening effect of the boron atoms in addition to the above factors. The rupture lives of monocrystalline Ni 3 Al are longer than those of polycrystalline alloys with a similar boron content.

Objective: To study the effect of hesperidin on expression of inducible nitric oxide synthase (iNOS) in cultured rabbit retinal pigment epithelial (RPE) cells under the condition of high glucose in vitro.

The present paper introduces micro ultrasonic powder molding (micro-UPM), a novel method for forming micro semi-crystalline polymer parts. In the proposed method, semi-crystalline polymer powder is rapidly heated and plasticized by ultrasonic vibration, after which the microcavity is filled with the melt under sonotrode pressure (PU) to form a variety of micro polymer parts. Differential scanning calorimetry, scanning electron microscopy, and nanoindentation tests demonstrate that micro-UPM UHMWPE (ultra-high molecular weight polyethylene) parts consists of nascent and melt-recrystallized phases and that energy concentrated at particle interfaces as a result of high-frequency friction, compressive deformation, and ultrasonic radiation leads to rapid diffusion and interpenetration of the chain segment. The particle interface melts result in strong co-crystallization during cooling. To investigate the effect of ultrasonic duration time (TU) on the quality of micro-UPM UHMWPE parts, different TU values are utilized to form UHMWPE parts at a PU of 16 MPa and a holding time of 5.0?s. As TU increases, the number and sizes of interparticle voids gradually decrease. A rise in the melting peak of the melt-recrystallized phase and a drop in the melting peak of the nascent phrase as well as crystallinity are further observed. When TU is only 1.5?s, the crystallinity of the micro plastic part reaches a minimum value of 54.3% and the melt-recrystallized phase fraction reaches a maximum value of 98.3%. Powder particle interfaces almost disappear in this case, and optimum quality of the micro-UPM UHMWPE part is achieved.

The numerical model of underwater explosion bubble coupling with free surface is created based on boundary integral method and the corresponding program is exploited to get the calculated result which presents satisfactory precision with experiment data. From the basic phenomenon of the interaction between bubble and free surface, the dynamic behavior of bubble near free surface is studied systematically employing the exploited program including the ring rebound of bubble near free surface and spike of free surface as well as the relation between distance parameter buoyancy parameter strength parameter and Bjerknes effect near free surface to summarize relative laws that the dynamic behavior near free surface has close relation with these characteristic parameters. In the process of study, scope of applicability of Blake rule on the basis of Kelvin_impulse theory is discussed and the reason for inactivation of Blake rule is interpreted to present references to research on dynamic behavior of underwater explosion bubble near free surface.

Through the measurements of positron lifetime and analysis of structure, the properties of helium in the ball-milled LaNi4.75Al0.25 and Zr50Co50 alloys were investigated. It was found that the amount of the injected helium increases with increasing helium pressure. It is comparatively easier for helium to enter the LaNi4.75Al0.25 alloy. The difference of the positron lifetime parameters between the above two specimens shows that the properties of the injected helium are different. For Zr50Co50, helium occupies the intersection of two or three crystallite interfaces and/or cluster of vacancies at grain boundaries or groups of vacancies firstly. With increasing pressure of the helium atmosphere, a small amount of helium enters the free volume of single vacancies, and thus vacancy-helium compounds form. For LaNi4.75Al0.25, helium enters the free volume of single vacancies and vacancy-helium compounds form.

The mechanism of hologram formation in dichromated gelatin is studied from all aspects with x-ray photoelectron spectroscopy (XPS). It is indicated that the Cr 2p(3/2) XPS spectrum of chromium used for hologram formation shows the property of exhibiting a continuous spectrum during the process of dichromated-gelatin hologram formation. By means of curve fitting and drawing a comparison between the obtained spectra and those of some standard substances, it is found that during the process of hologram formation the valence of chromium used for hologram formation changes from Cr6+ to a quasi-trivalent state to Cr4+, and finally to Cr3+. Accordingly, the corresponding compound experiences a change from (NH4)2Cr2O7 to the transient state close to the feature of Cr(OH)3 to CrO2, and finally to Cr3+, cross linking with the gelatin. The essence of the chemical change at different stages of the process of hologram formation was found, and so the present mechanism, which is determined with comparatively abundant proof, should replace previously reported mechanisms, which were too simple, varied, and sometimes even mutually contradictory. According to the experimental results and the fact that a solid-film reaction, which differs from that of the liquid-phase reaction, was studied, possible chemical-reaction equations of the process of hologram formation are established. This becomes the basis for explaining previous findings and expanding further research.