The effect of the active element yttrium and its content on the oxidation behavior of GH4169 Ni-based superalloy at extreme temperature was studied by isothermal oxidation experiments. The results show that the oxide scale of GH4169 alloy presents a multi-layer structure, in which the continuous and dense Cr2O3 oxide layer is located in the subouter layer (II layer) and the continuous Nb-rich layer is in the subinner layer (III layer). These layers can inhibit the diffusion of oxygen and alloying elements, preventing the further oxidation of the alloy. The appropriate addition of yttrium can promote the selective oxidation of Cr element, reduce the thickness of the oxide scale and the oxidation rate of the alloy, inhibit the formation of voids at the interface of the oxide scale/alloy matrix, improve the resistance of the alloy to spalling as well as the adhesion of the oxide scale, and improve the high-temperature oxidation resistance of the alloy. Of those tested, the alloy containing 0.04 wt.%Y has the lowest oxidation weight gain, the slowest oxidation rate, and less oxide scale spalling. Based on this, the effect of yttrium on the high-temperature oxidation behavior of GH4169 Ni-based superalloy and its mechanism were revealed.
This research added rare Earth elements Ce to the P110-grade oil casing steel to reveal their influence on the inclusions and tensile properties. The content of cerium in the steel varied from 0 to 452 ppm. Based on the classical thermodynamic calculation, the predominance diagram of Re-containing inclusions in P110-grade steel was obtained. The evolution route of the inclusions composition with the increasing cerium content in the steel was xCaOâ yAl2O3 â Al2O3-CeAlO3 â Ce2O3-CeAlO3 â Ce2O3-Ce2O2S â Ce2O2S, which agreed well with the thermodynamic analysis. As the cerium content at 235 ppm, the size of Ce containing inclusions has a minimal size at 2.82 µm. Suitable Ce content can modify the big-size xCaOâ yAl2O3 inclusions into small-size Re-containing inclusions. The results demonstrate that the tensile performance of this steel can be improved as the cerium content increases from 0 to 235 ppm. However, once the cerium content exceeds 235 ppm, further increases in cerium content led to a decline in performance. The experimental results shows that the presence of large-sized Ce2O2S inclusions and the change of microstructure, will lead to the decrease in tensile performance.
Quasi-solid-state potassium-ion batteries (SSPIBs) are of great potential for commercial use due to the abundant reserves and cost-effectiveness of resources, as well as high safety. Gel polymer electrolytes (GPEs) with high ionic conductivity and fast interfacial charge transport are necessary for SSPIBs. Here, the weak electrostatic force between K+ and electronegative functional groups in the ethoxylated trimethylolpropane triacrylate (ETPTA) polymer chains, which can promote fast migration of free K+, is revealed. To further enhance the interfacial reaction kinetics, a multilayered GPE by in situ growth of poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) on ETPTA (PVDF-HFP|ETPTA|PVDF-HFP) is constructed to improve the interface contact and provide sufficient K+ concentration in PVDF-HFP. A high ion transference number (0.92) and a superior ionic conductivity (5.15 × 10-3 S cm-1) are achieved. Consequently, the SSPIBs with both intercalation-type (PB) and conversion-type (PTCDA) cathodes show the best battery performance among all reported SSPIBs of the same cathode. These findings demonstrate that potassium-ion batteries have the potential to surpass Li/Na ion batteries in solid-state systems.
PURPOSE: Catheter-related bladder discomfort (CRBD) is an unpleasant experience for patients during postoperative recovery. Dexmedetomidine is an effective therapy for CRBD; however, little is known about dexmedetomidine administration for treating CRBD during recovery. This study was conducted to determine the 90% effective dose (ED90) of dexmedetomidine to provide adequate treatment for CRBD during recovery. DESIGN: Prospective, single-blind dose-finding study. METHODS: This open-label, single-group trial included severe postoperative CRBD patients aged 18 to 80 years and the American Society of Anesthesiologists' physical status class I or II in the postanesthesia care unit. All patients were assigned to receive intravenous dexmedetomidine. The dose of dexmedetomidine was determined using the modified Dixon's up-and-down method. The first patient was treated with 0.4 mcg/kg dexmedetomidine. An increment or decrement of 0.05 mcg/kg dexmedetomidine was used based on the response of the previous patient. A successful treatment was defined as the transition from severe CRBD to mild CRBD. Probit regression was applied to calculate the ED90 of dexmedetomidine. FINDINGS: A total of 29 patients were recruited, of whom 14 patients (48.3%) underwent successful treatment. The ED90 of dexmedetomidine required for successfully treating postoperative CRBD was 0.55 mcg/kg (95% confidence interval: 0.49-1.54 mcg/kg). CONCLUSIONS: The ED90 of dexmedetomidine for the successful treatment of severe postoperative CRBD during recovery is 0.55 mcg/kg.
Dexmedetomidine , Urinary Catheterization , Humans , Dexmedetomidine/therapeutic use , Pain, Postoperative/drug therapy , Pain, Postoperative/etiology , Prospective Studies , Single-Blind Method , Urinary Bladder , Urinary Catheterization/adverse effects , Urinary Catheters/adverse effects
A new surface-enhanced Raman spectroscopy (SERS) biosensor of Graphene@Ag-MLF composite structure has been fabricated by loading AgNPs on graphene films. The response of the biosensor is based on plasmonic sensing. The results showed that the enhancement factor of three different spores reached 107 based on the Graphene@Ag-MLF substrate. In addition, the SERS performance was stable, with good reproducibility (RSD<3%). Multivariate statistical analysis and chemometrics were used to distinguish different spores. The accumulated variance contribution rate was up to 96.35% for the top three PCs, while HCA results revealed that the spectra were differentiated completely. Based on optimal principal components, chemometrics of KNN and LS-SVM were applied to construct a model for rapid qualitative identification of different spores, of which the prediction set and training set of LS-SVM achieved 100%. Finally, based on the Graphene@Ag-MLF substrate, the LOD of three different spores was lower than 102 CFU/mL. Hence, this novel Graphene@Ag-MLF SERS substrate sensor was rapid, sensitive, and stable in detecting spores, providing strong technical support for the application of SERS technology in food safety.
Graphite , Spores, Bacterial , Reproducibility of Results , Spectrum Analysis, Raman , Chemometrics
Considering the problem of the weak bonding interface structure between the rolling mill oil and film bearing bushings of Babbitt alloy and steel substrate, a numerical simulation of the layered bimetallic ZChSnSb8Cu4/steel by tungsten inert gas (TIG)-metal inert gas (MIG) hybrid welding process was carried out using Simufact Welding software (version 2020). In this study, the TIG-MIG hybrid welding process was simulated to obtain the temperature field and the stress field distributions. The residual stress and the deformation of the weldment were also analyzed using the calculated results. The results showed that the temperature gradient and the thermal stress were reduced in TIG-MIG hybrid welding compared to the conventional MIG welding preparation of layered bimetal ZChSnSb8Cu4/steel, which resulted in an improvement in the structural stability of the weldment. The temperature field and deformation of TIG-MIG hybrid welding of Babbitt alloy were studied under different controlled electrode spacings and TIG welding currents, and it was found that as electrode spacing increased, so did heat loss. Furthermore, with increased TIG welding current, compressive stress increased and tensile stress at the weld decreased, and the maximum thermal efficiency of welding was with a preheating current of 60 A.
Coupled with the results of a 2D heat transfer model, a 3D electromagnetic stirring round billet model is developed, which is considered for the difference in the conductivity of solidified shell and molten steel. The electromagnetic field distribution features of the billet and the effect of round billet sizes on the electromagnetic field are investigated. It is found that as the solidified shell conductivity of the Φ600 mm round billet increases from 7.14 × 105 S·m-1 to 1.0 × 106 S·m-1, the magnetic induction intensity decreases and the maximum value of electromagnetic force drops from 7976.26 N·m-3 to 5745.32 N·m-3. The magnetic induction intensity on the center axis of the stirrer rarely changes in the range of Φ100-Φ200 mm. With the increase in the round billet from Φ300 mm to Φ600 mm, the magnetic induction intensity and the electromagnetic force on the center axis of the stirrer decrease slowly and then significantly. In the range of 2-8 Hz, as the current strength reaches its maximum, the electromagnetic force can be increased by increasing the current frequency for round billets of Φ100-Φ500 mm, while there is an optimal current frequency for round billets larger than Φ600 mm.
In order to improve the yield of steel produced in the converter and the quality of the molten steel, and to understand the distribution of the flow field in the converter and ladle during the steelmaking process, the CFD fluid simulation software Fluent 2020 R2 was used to analyze the flow field of the converter static steelmaking process. The aperture of the steel outlet and the timing of the vortex formation under different angles were studied, as well as the disturbance level of the injection flow in the ladle molten pool. The study revealed that in the steelmaking process, the emergence of tangential vectors caused the entrainment of slag by the vortex, whereas in the later stages of steelmaking, the turbulent flow of slag disrupted the vortex, resulting in its dissipation. When the converter angle increases to 90°, 95°, 100°, and 105°, the eddy current occurrence time is 43.55 s, 66.44 s, 68.80 s, and 72.30 s, and the eddy current stabilization time is 54.10 s, 70.36 s, 70.95 s, and 74.26 s, respectively. When the converter angle is 100-105°, it is suitable to add alloy particles into the ladle molten pool. When the tapping port diameter is 220 mm, the eddy current inside the converter changes and the mass flow rate of the tapping port is "oscillating". When the aperture of the steel outlet was 210 mm, the steelmaking time could be shortened by about 6 s without affecting the internal flow field structure of the converter.
It is difficult to observe the nucleation mechanism of inclusions in real-time. In this study, the nucleation process of zirconium oxide inclusions was systematically studied by classical nucleation theory and first principles. Zr deoxidized steel with 100 ppm Zr addition was processed into metallographic samples for scanning electron microscopy energy-dispersive spectroscopy observation. The electrolytic sample was analyzed by micro X-ray diffraction and transmission electron microscopy, and the zirconium oxide in the sample was determined to be ZrO2. The nucleation rate and radius of the ZrO2 inclusions were calculated by classical nucleation theory, and they were compared with the experimental values. There was a considerable difference between the experimental and theoretical values of the nucleation rate. The effect of the nucleation size was analyzed by first-principles calculation, and the thermodynamic properties of ZrO2 clusters and nanoparticles were analyzed by constructing (ZrO2)n (n = 1-6) clusters. The thermodynamic properties of ZrO2 calculated by first principles were consistent with the values in the literature. Based on two-step nucleation theory, the nucleation pathway of ZrO2 is as follows: Zratom + Oatom â (ZrO2)n â (ZrO2)2 â core (ZrO2 particle)-shell ((ZrO2)2 cluster) nanoparticle â (ZrO2)bulk.
The corrosion resistance of the HRB400 steel rebar alloyed with Cr and rare earths (RE) was systematically studied from two aspects, including the properties of the passive film and the protectiveness of the rust layer. The results presented that Cr increased the corrosion resistance of the steel rebar through stabilizing the passive film and was not involved in the formation of corrosion pits, while the pitting corrosion was initiated by the dissolution of (RE)2O2S inclusion, resulting in the local acidification at the bottom of the corrosion pits, which decreased the stability of the passive film. As for the long-term corrosion process, both Cr and RE decreased the corrosion rate of the steel rebar, which was related to the promotion effect on the formation of α-FeOOH in the rust layer from Cr and RE.
A transient numerical simulation method is used to investigate the temperature field, velocity field, and solidified field of large-size Waspaloy superalloy during the electroslag remelting (ESR) process. The effects of melting rate, filling rate, and thickness of the slag layer on the molten pool shape and dendrite arm spacing evolution have been discussed. The temperature in the slag pool is high and relatively uniformly distributed, the temperature range is 1690-1830 K. The highest temperature of the melt pool appears in the center of the slag-metal interface, 1686 K. There are two pairs of circulating vortices in the slag pool, the side vortices are caused by the density difference caused by the buoyancy of the slag, the center vortices are the result of the combined action of electromagnetic force and the momentum of the falling metal droplets. The molten pool depth and dendrite arm spacing increase with the increase of melting rate, but the slag layer thickness and electrode filling rate have little effect on the molten pool morphology and dendrite arm spacing if the droplet effect is not taken into account. Considering the morphology and depth of the molten pool as well as the size and distribution uniformity of the dendrite arm spacing, it is appropriate to maintain the melting rate at 5.8 kg/min for the industrial scale ESR process with the ingot diameter of 580 mm.
In this study, the industrial, experimental effect of a plasma heating system in the form of graphite electrode in the tundish of double-strand slab caster was evaluated for the first time. The system uses three graphite electrodes, two of which are cathodes and one of which is an anode, to form a conductive loop through molten steel in the tundish. The system is built on an old two-strand slab caster and is installed on the premise that the original ladle tundish equipment remains unchanged. The normal working power of the system is up to 1500 kW, and the heating rate of molten steel in the tundish can reach 1.0 °C/min under conditions of 5 t/min total steel throughput and a tundish capacity of 50 t. After the system was put into operation, the purity of molten steel undergoing heating was investigated. The sample analysis of low carbon steel and ultra-low carbon steel before and after heating showed that the contents of N and O in the steel did not increase, while the size of the oxide inclusions near the heating point increased but showed little change in terms of the overall quantity. This process benefited from the addition of inert gas during the heating process to control the atmosphere in the heating area, which prevents reoxidation. The sample analysis also showed that there is no obvious carbon absorption phenomenon after heating, and the fluctuation in C content is within 0.0001%, which is consistent with the general production results. By using this system, the temperature of molten steel in the steelmaking process can be reduced by 10~15 °C, allowing continuous low superheat casting to be supported, which is helpful for reducing production costs and improving the solidified structure inside the slab. The results of the study show that the plasma heating technology can be applied to the continuous casting of low carbon-nitrogen steel slabs, which shows the benefits of reducing emissions and improving production efficiency.
Mycobacterium tuberculosis (M. tuberculosis) Rv1002c encodes the protein O-mannosyltransferase (PMT), which catalyzes the transfer of mannose to serine or threonine residues of proteins. We explored the function of PMT in vitro and in vivo. Rv1002c protein was heterogeneously overexpressed in nonpathogenic Mycobacterium smegmatis (named as MS_Rv1002c). A series of trials including mass spectrometry, transmission electron microscope, biofilm formation and antibiotics susceptibility were performed to explore the function of PMT on bacterial survival in vitro. Mouse experiments were carried out to evaluate the virulence of PMT in vivo. PMT decreased the cell envelope permeability and promoted microbial biofilm formation. PMT enhanced the mycobacterial survival in vivo and inhibited the release of pro-inflammatory cytokines in serum. The function might be associated with an increased abundance of some mannoproteins in culture filtrate (CF). PMT is likely to be involved in mycobacterial survival both in vivo and in vitro due to increasing the mannoproteins abundance in CF.
Biofilms/growth & development , Cell Membrane Permeability/physiology , Mannosyltransferases/metabolism , Mycobacterium tuberculosis/pathogenicity , Animals , Bacterial Proteins/metabolism , Cytokines/metabolism , Inflammation/metabolism , Inflammation/microbiology , Mice , Mice, Inbred BALB C , Mycobacterium smegmatis/metabolism , Mycobacterium tuberculosis/metabolism , Permeability , Virulence/physiology
What is already known on this topic? Brucellosis is a zoonotic infectious disease caused by Brucella spp. The main source of infection in human brucellosis is sick animals, mainly including sheep, goat, and cattle, but sika deer (Cervus nippon) can also cause human brucellosis. The first human brucellosis case in Guizhou Province was reported in 2009, and no brucellosis outbreak was reported caused by sika deer ever before. What is added by this report? This is the first reported outbreak of human brucellosis caused by sika deer in Guizhou Province. Inappropriate regulation of animal movement may be the main driver of introducing and spreading brucellosis in southern areas. The ability to diagnose brucellosis in both humans and animals was weak in the county where the outbreak took place. What are the implications for public health practice? It was suggested to prioritize occupational protection and health education for sika deer breeders. The inspection of the movement of animals and the reimbursement policy need to be improved.
Protein O-mannosyltransferase (PMT) catalyzes an initial step of protein O-mannosylation of Mycobacterium tuberculosis (Mtb) and plays a crucial role for Mtb survival in the host. To better understand the role of PMT in the host innate immune response during mycobacterial infection, in this study, we utilized Mycobacterium smegmatis pmt (MSMEG_5447) gene knockout strain, ΔM5447, to infect THP-1 cells. Our results revealed that the lack of MSMEG_5447 not only impaired the growth of M. smegmatis in 7H9 medium but also reduced the resistance of M. smegmatis against lysozyme and acidic stress in vitro. Macrophage infection assay showed that ΔM5447 displayed attenuated growth in macrophages at 24 h post-infection. The production of TNF-α and IL-6 and the activation of transcription factor NF-κB were decreased in ΔM5447-infected macrophages, which were further confirmed by transcriptomic analysis. Moreover, ΔM5447 failed to inhibit phagosome-lysosome fusion in macrophages. These findings revealed that PMT played a role in modulating the innate immune responses of the host, which broaden our understanding for functions of protein O-mannosylation in mycobacterium-host interaction.
BACKGROUND: Coronavirus disease 2019 (COVID-19) has become a worldwide public health emergency. This study aimed to investigate the clinical significance of liver blood tests in COVID-19 patients. METHODS: The analysis included clinical data of 23 patients with suspected COVID-19 and 66 patients with confirmed COVID-19 from January 25 to February 20, 2020. The relationship between liver blood test results, liver condition (HBsAb positive, HBcAb positive, and fatty liver disease), and duration of hospital stay among COVID-19 patients was analyzed. RESULTS: The median hospital stay of COVID-19 patients was 6 days. Serum albumin (Alb) level was lower in patients with COVID-19 confirmed on admission than in patients with suspected COVID-19 (40.08 g/L vs 42.50 g/L, P = .016), while the level of aspartate aminotransferase (AST) was higher (23 U/L vs 18 U/L, P = .005). Abnormal results of liver blood tests in patients with COVID-19 included increased levels of alanine transaminase (ALT) (21.2%, 14 patients), AST (15.2%, 10 patients), and gamma-glutamyl transpeptidase (GGT) (22.7%, 15 patients). After 5-10 days of treatment, levels of Alb and AST in COVID-19 patients were significantly decreased (P < .001 and P = .027, respectively). Abnormal levels of Alb and AST in patients with COVID-19 were not associated with the liver condition (all P > .05). In addition, only levels of AST were positively correlated with the duration of hospital stay (r = .334, P = .007). CONCLUSION: Abnormal results of the liver blood test were found in COVID-19 patients. The COVID-19 patients on admission with the higher levels of AST might have longer hospital stays.
Aspartate Aminotransferases/blood , Betacoronavirus/physiology , Coronavirus Infections/blood , Coronavirus Infections/enzymology , Length of Stay , Pneumonia, Viral/blood , Pneumonia, Viral/enzymology , Adult , COVID-19 , Coronavirus Infections/therapy , Coronavirus Infections/virology , Female , Humans , Liver/virology , Liver Function Tests , Male , Middle Aged , Pandemics , Pneumonia, Viral/therapy , Pneumonia, Viral/virology , SARS-CoV-2
OBJECTIVE: An outbreak of pneumonia named COVID-19 caused by a novel coronavirus in Wuhan is rapidly spreading worldwide. The objective of the present study was to clarify further the clinical characteristics and blood parameters in COVID-19 patients. MATERIALS AND METHODS: Twenty-three suspected patients and 64 patients with laboratory-confirmed SARS-Cov-2 infection were admitted to a designated hospital. Epidemiological, clinical, laboratory, and treatment data were collected and analyzed. RESULTS: Of the 64 patients studied, 47 (73.4%) had been exposed to a confirmed source of COVID-19 transmission. On admission, the most common symptoms were fever (75%) and cough (76.6%). Twenty-eight (43.8%) COVID-19 patients showed leukopenia, 10 (15.6%) showed lymphopenia, 47 (73.4%) and 41 (64.1%) had elevated high-sensitivity C-reactive protein (hsCRP) and erythrocyte sedimentation rate (ESR), respectively, and 30 (46.9%) had increased fibrinogen concentration. After the treatment, the counts of white blood cells and platelets, and the level of prealbumin increased significantly, while aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and hsCRP decreased. COVID-19 patients with the hospital stay longer than 12 days had higher body mass index (BMI) and increased levels of AST, LDH, fibrinogen, hsCRP, and ESR. CONCLUSIONS: Results of blood tests have potential clinical value in COVID-19 patients.
Betacoronavirus/isolation & purification , Biomarkers/blood , Coronavirus Infections/complications , Cough/diagnosis , Fever/diagnosis , Leukopenia/diagnosis , Lymphopenia/diagnosis , Pneumonia, Viral/complications , Adult , COVID-19 , Coronavirus Infections/virology , Cough/blood , Cough/etiology , Female , Fever/blood , Fever/etiology , Humans , Leukopenia/blood , Leukopenia/etiology , Lymphopenia/blood , Lymphopenia/etiology , Male , Middle Aged , Pandemics , Pneumonia, Viral/virology , Prognosis , SARS-CoV-2
Bacterial glycoproteins have been investigated as vaccine candidates as well as diagnostic biomarkers. However, they are poorly understood in Mycobacterium bovis strain bacille Calmette-Guérin (BCG), a non-pathogenic model of Mycobacterium tuberculosis. To understand the roles of secreted O-mannosylated glycoproteins in BCG, we conducted a ConA lectin-affinity chromatography and mass spectra analysis to identify O-mannosylated proteins in BCG culture filtrate. Subsequent screening of antigens was performed using polyclonal antibodies obtained from a BCG-immunized mouse, with 15 endogenous O-mannosylated proteins eventually identified. Of these, BCG_0470 and BCG_0980 (PstS3) were revealed as the immunodominant antigens. To examine the protective effects of the antigens, recombinant antigens proteins were first expressed in Mycobacterium smegmatis and Escherichia coli, with the purified proteins then used to boost BCG primed-mice. Overall, the treated mice showed a greater delayed-type hypersensitivity response in vivo, as well as stronger Th1 responses, including higher level of IFN-γ, TNF-α, and specific-IgG. Therefore, mannosylated proteins BCG_0470 and BCG_0980 effectively amplified the immune responses induced by BCG in mice. Together, our results suggest that the oligosaccharide chains containing mannose are the antigenic determinants of glycoproteins, providing key insight for future vaccine optimization and design.
Mycobacterium tuberculosis is capable of escaping the clearance of immune system mainly due to its complex constituents of cell wall. Certain studies show that glycoproteins are involved in immune evasion and act as virulence factors. Peptidoglycan deacetylase Rv1096 is a member of mannosylated proteins. Previously, we reported Rv1096 protein contributed to the resistance of Mycobacterium smegmatis (M. smegmatis) to lysozyme, but more characterization of this protein is required where further intracellular function is unknown. Here, Rv1096 was heterologously over-expressed in the fast-growing and nonpathogenic M. smegmatis (named as M. smegmatis/Rv1096). We observed the morphological alterations in M. smegmatis/Rv1096 including an elongated rod-like shape and increased amounts of Z-rings, which implied that Rv1096 facilitated the cell growth and division. Moreover, a series of assays concerning the interaction between M. smegmatis/Rv1096 and host were carried out. The results showed that M. smegmatis/Rv1096 evaded the killing of macrophages due to the inhibition of phagosome-lysosome fusion, nicotinamide adenine dinucleotide phosphate oxidase activity and reactive oxygen species production. The secretion of interleukin-12 and tumor necrosis factor-α was also impaired by Rv1096. In addition, five putative interaction partners of Rv1096 were identified, which possibly cooperated with Rv1096 in cell division and immune regulation. These results suggested that Rv1096 had effects on mycobacterial division and might act as a virulence factor to mediate the immune evasion in macrophage during mycobacterial infection.
Bacterial Proteins/metabolism , Cell Division , Mycobacterium smegmatis , Peptidoglycan/metabolism , Cell Wall/metabolism , Histone Deacetylases/metabolism , Host-Pathogen Interactions , Immune Evasion , Interleukin-12/metabolism , Macrophages/metabolism , Macrophages/microbiology , Microbial Viability , Mycobacterium Infections , Mycobacterium smegmatis/growth & development , Mycobacterium smegmatis/metabolism , Mycobacterium tuberculosis/pathogenicity , Reactive Oxygen Species/metabolism , Tumor Necrosis Factor-alpha/metabolism , Virulence Factors/metabolism
OBJECTIVE: Wear-induced aseptic loosening has been accepted as one of the main reasons for failure of total hip arthroplasty. Ceramic wear debris is generated following prosthesis implantation and plays an important part in the upregulation of inflammatory factors in total hip arthroplasty. The present study investigates the influence of ceramic debris on osteoblasts and inflammatory factors. METHODS: Ceramic debris was prepared by mechanical grinding of an aluminum femoral head and added to cultures of MC3T3-E subclone 14 cells at different concentrations (i.e. 0, 5, 10, and 15 µg/mL). Cell proliferation was evaluated using a Cell Counting Kit (CCK-8), and cell differentiation was assessed by mRNA expression of alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN). In addition, cell bio-mineralization was evaluated through alizarin red S staining, and release of tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1ß), and interleukin-6 (IL-6) was measured through enzyme-linked immunosorbent assays (ELISA). Furthermore, mRNA expression of Smad1, Smad4, and Smad5 and protein expression of phosphorylated Smad1, Smad4, and Smad5 were measured by reverse transcriptase polymerase chain reaction (RT-PCR) and western blotting. RESULTS: The ceramic debris had irregular shapes and sizes, and analysis of the size distribution using a particle size analyzer indicated that approximately 90% of the ceramic debris was smaller than 3.2 µm (2.0 ± 0.4 µm), which is considered clinically relevant. The results for mRNA expression of ALP, OCN, and OPN and alizarin red S staining indicated that cell differentiation and bio-mineralization were significantly inhibited by the presence of ceramic debris at all tested concentrations (P < 0.05, and the values decreased gradually with the increase of ceramic debris concentration), but the results of the CCK-8 assay showed that cell proliferation was not significantly affected (P > 0.05; there was no significant difference between the groups at 1, 3, and 5 days). In addition, the results of ELISA, RT-PCR, and western blotting demonstrated that ceramic debris significantly promoted the release of inflammatory factors, including TNF-α, IL-ß, and IL-6 (P < 0.05, and the values increased gradually with the increase of ceramic debris concentration), and also greatly reduced the mRNA expression of Smad1, Smad4, and Smad5 (the values decreased gradually with the increase of ceramic debris concentration) as well as protein expression of phosphorylated Smad1, Smad4, and Smad5. CONCLUSION: Ceramic debris may affect differentiation and bio-mineralization of MC3T3-E subclone 14 cells through the bone morphogenetic protein/Smad signaling pathway.
Ceramics/adverse effects , Foreign Bodies/complications , Hip Prosthesis/adverse effects , Osteoblasts/cytology , 3T3 Cells , Alkaline Phosphatase/metabolism , Animals , Arthroplasty, Replacement, Hip , Biomarkers/metabolism , Blotting, Western , Cell Differentiation , Cell Proliferation , Cytokines/metabolism , Mice , Osteocalcin/metabolism , Osteopontin/metabolism , Smad Proteins/metabolism
