In this work, a novel Co–Cr–Fe–Ni–Mo–Si multi-principal element alloy (MPEA)-based Laves phase alloy (T-MPEA) is designed and fabricated. The microstructure, mechanical properties and dry sliding ...wear properties of the new alloy are investigated, and compared to those of T-800 (Co-based) and T-700 (Ni-based) Tribaloy alloys. Hard intermetallic Laves phases disperse in face-centered-cubic solid solution in T-MPEA, and the Mo- and Si-rich Laves phase reaches a fraction of ∼60%. The compressive strength of T-MPEA reaches 1912 MPa, which is higher than that of T-700 and close to that of T-800. T-MPEA exhibits a mean hardness of 624 HV0.3, and maintains a high hardness above 500 HV0.3 even at 800 °C. Owing to its high strength and hardness, T-MPEA exhibits higher wear-resistance, compared to that of T-700 in all dry sliding wear tests, from room temperature to 600 °C. Owing to the high resistance to softening and dense oxide film formation at high temperatures, T-MPEA exhibits excellent high-temperature wear-resistance.
Heat accumulation and rapid cooling during the electro-spark deposition (ESD) process led to the inevitable occurrence of cracks. In this paper, TiVCrNiSi0.1 ESD coatings were prepared on the surface ...of Ti6Al4V. The TiVCrNiSi0.1 ESD coatings presented excellent resistance to oxidation and possessed a self-healing ability for crack inside of coating at high temperatures. The oxidation kinetics of TiVCrNiSi0.1 coatings at 700 °C conform to the parabolic law, the oxidation rate of TiVCrNiSi0.1 coating at 700 °C compared with Ti6Al4V decreased by 15 %. During the oxidation process at 700 °C, the initial cracks in the TiVCrNiSi0.1 coating self-healed due to the formation of oxides. During the formation of oxides at high temperature, a Laves phase with amorphous SiO2 on the surface is formed at the interface between the coating and the oxide layer. The existence of amorphous phase can effectively prevent the external diffusion of alloying elements and the internal diffusion of O. The TiVCrNiSi0.1-oxide composite coating has excellent wear resistance. The hardness of TiVCrNiSi0.1 coatings after self-healing at high temperature was 3.9 times that of the Ti6Al4V substrate, and the wear rate is reduced by about 80 % compared to Ti6Al4Vsubstrate.
•A TiVCrNiSi0.1 coating with excellent oxidation- and wear-resistance was prepared by ESD.•Oxidation kinetics and microstructure of the dense oxide layer of the ESD coatings at 700 °C was revealed.•The initial cracks of the ESD coating self-healed at high temperature due to the formation of oxides.•The wear rate of the composite coating after self-healing was about 80 % lower than Ti6Al4V substrate.
This study investigates the effects of varying bias voltages on the crystallographic orientation and properties of DCMS + HiPIMS-deposited chromium coatings. Under bias voltages varying from 100 to ...500 V, dense Cr coatings were obtained, and the deposition rate decreased by 13 %. The bias voltage significantly impacts the hardness, crystallographic orientation, electrical conductivity, and bonding strength of the coating. As the bias voltage increases, the hardness of the Cr coating gradually increases. The crystallographic orientation of the coating is governed collectively by surface energy, strain energy, and sputtering effects. The preferential crystallographic orientation of the Cr coating transitions from (222) to (110), subsequently changing to a mixed preferential crystallographic orientation of (110), (211), and (222). Under the combined influence of thermal effects and ion bombardment, a (110) preferential crystallographic orientation was obtained at a bias voltage of 300 V, featuring moderate hardness and optimal wear resistance. This study establishes that the electrical characteristics of the coatings have a significant correlation with bias voltage levels.
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•By manipulating ion energy, DC/HiPIMS-Cr coatings with varied preferential orientations were achieved.•The mechanism of preferential orientation evolution of Cr coating under bias voltage.•The interrelationships between characteristics and preferential orientations.
In this work, TiCrNiVSi0.1 coatings were prepared on TC4 alloy by CNC-controlled automatic electro-spark deposition (ESD). The TOPSIS-based Taguchi method was applied for multi-criteria optimization ...of ESD coating quality. Frequency (f), capacitance (c), and electrode moving speed (v) were considered process parameters for optimizing the coating quality criteria, which included coating thickness, coating coverage, and porosity in the coating. The optimized parametric setting of the ESD process (f = 700 Hz, c = 270 μF, v = 150 mm/min) was obtained. MPEA coatings with a thickness of about 70 um, a coverage rate almost reaching 100%, and porosity as low as about 1% were prepared. The wear- and burn-resistance functions of the TiCrNiVSi0.1 ESD coatings were investigated. The wear rates of the coating at room temperature and 400 °C are one-sixth and one-fourth of the TC4 alloy, respectively. A TiCrNiVSi0.1 alloy coating was deposited and significantly improved the burn resistance of the TC4 alloy.
Device performance and in particular device stability for blue perovskite light-emitting diodes (PeLEDs) remain considerable challenges for the whole community. In this manuscript, we conceive an ...approach by tuning the 'A-site' cation composition of perovskites to develop blue-emitters. We herein report a Rubidium-Cesium alloyed, quasi-two-dimensional perovskite and demonstrate its great potential for pure-blue PeLED applications. Composition engineering and in-situ passivation are conducted to further improve the material's emission property and stabilities. Consequently, we get a prominent film photoluminescence quantum yield of around 82% under low excitation density. Encouraged by these findings, we finally achieve a spectra-stable blue PeLED with the peak external quantum efficiency of 1.35% and a half-lifetime of 14.5 min, representing the most efficient and stable pure-blue PeLEDs reported so far. The strategy is also demonstrated to be able to generate efficient perovskite blue emitters and PeLEDs in the whole blue spectral region (from 454 to 492 nm).
Due to the highly evolved industrialization and modernization, air quality has deteriorated in most countries. As reported by the World Health Organization (WHO), air pollution is now considered as ...one of the major threats to global health and a principal risk factor for noncommunicable diseases. Meanwhile, the increasing worldwide prevalence of overweight and obesity is attracting more public attentions. Recently, accumulating epidemiological studies have provided evidence that overweight and obesity may be partially attributable to environmental exposure to air pollution. This review summarizes the epidemiological evidence for the correlation between exposure to various outdoor and indoor air pollutants (mainly particulate matter (PM), nitrogen oxides (NOx), ozone (O3), and polycyclic aromatic hydrocarbons (PAHs)) and overweight and obesity outcomes in recent years. Moreover, it discusses the multiple effects of air pollution during exposure periods throughout life and sex differences in populations. This review also describes the potential mechanism underlying the increased risk of obesity caused by air pollution, including inflammation, oxidative stress, metabolic imbalance, intestinal flora disorders and epigenetic modifications. Finally, this review proposes macro- and micro-measures to prevent the negative effects of air pollution exposure on the obesity prevalence.
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•The link between air pollution and obesity in different life periods is described.•Mechanisms including inflammation, metabolism, flora and epigenetics are raised.•Measures are proposed to reduce the risk of obesity related with air pollution.
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•PAN/SiO2/CTAB nanofibrous membranes were fabricated for air filtration and sterilization.•The contribution of the SiO2 electret effect on filtration performance was investigated.•The ...membranes exhibit high filtration efficiency and low airflow resistance.•The membranes possess a bacteriostasis rate more than 99% against E. coli and S. aureus.•The antibacterial mechanism of PAN/SiO2/CTAB membranes was proposed.
Air particulate pollution from increasing industrialization poses an enormous threat to public health. It is therefore of particular importance to develop air filters with excellent filtration properties and antimicrobial properties. Here we design a novel air filter for outdoor personal protection. The air filter’s composite nanofibrous materials are prepared by electrospinning method using polyacrylonitrile (PAN) as the base polymer, silica dioxide (SiO2) as the electret r and cetyltrimethylammonium bromide (CTAB) as the antimicrobial agent. Fourier-infrared spectroscopy, surface potential, and X-ray photoelectron spectroscopy characterization reveal the successful incorporation of SiO2 and CTAB into PAN. The air filtration test shows that the composite nanofibrous membrane has outstanding PM0.3 filtration efficiency (98.5%) and lower pressure drop (76 Pa) at 32 L/min flow rate. Moreover, the durability tests show that the composite nanofibrous membranes have a long lifetime in terms of filtration performance. The filtration efficiency is reduced by only 2% after 48 h. In addition, the antimicrobial properties were tested by implementing both E. coli and S. aureus with up to a 99% bacteriostasis rate. Thus, this work improves the application potential of high-performance air filters for the removal of particulate pollution and may provide useful insights into the design of next-generation air filters suitable for applications in high antibacterial applications.
Pose estimation is a particularly important link in the task of robotic bin-picking. Its purpose is to obtain the 6D pose (3D position and 3D posture) of the target object. In real bin-picking ...scenarios, noise, overlap, and occlusion affect accuracy of pose estimation and lead to failure in robot grasping. In this paper, a new point-pair feature (PPF) descriptor is proposed, in which curvature information of point-pairs is introduced to strengthen feature description, and improves the point cloud matching rate. The proposed method also introduces an effective point cloud preprocessing, which extracts candidate targets in complex scenarios, and, thus, improves the overall computational efficiency. By combining with the curvature distribution, a weighted voting scheme is presented to further improve the accuracy of pose estimation. The experimental results performed on public data set and real scenarios show that the accuracy of the proposed method is much higher than that of the existing PPF method, and it is more efficient than the PPF method. The proposed method can be used for robotic bin-picking in real industrial scenarios.
Lupus nephritis (LN) is one of the most severe complications of systemic lupus erythematosus (SLE). Circular RNAs (circRNAs) can act as competitive endogenous RNAs (ceRNAs) to regulate gene ...transcription, which is involved in mechanism of many diseases. However, the role of circRNA in lupus nephritis has been rarely reported. In this study, we aim to investigate the clinical value of circRNAs and explore the mechanism of circRNA involvement in the pathogenesis of LN.
Renal tissues from three untreated LN patients and three normal controls (NCs) were used to identify differently expressed circRNAs by next-generation sequencing (NGS). Validated assays were used by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The interactions between circRNA and miRNA, or miRNA and mRNA were further determined by luciferase reporter assay. The extent of renal fibrosis between the two groups was assessed by Masson-trichome staining and immunohistochemistry (IHC) staining.
159 circRNAs were significantly dysregulated in LN patients compared with NCs. The expression of hsa_circ_0123190 was significantly decreased in the renal tissues of patients with LN (P = 0.014). Bio-informatics analysis and luciferase reporter assay illustrated that hsa_circ_0123190 can act as a sponge for hsa-miR-483-3p, which was also validated to interact with APLNR. APLNR mRNA expression was related with chronicity index (CI) of LN (P = 0.033, R
= 0.452). Moreover, the fibrotic-related protein, transforming growth factor-β1 (TGF-β1), which was regulated by APLNR, was more pronounced in the LN group (P = 0.018).
Hsa_circ_0123190 may function as a ceRNA to regulate APLNR expression by sponging hsa-miR-483-3p in LN.
The unique clinical features of pregnancy termination in the second trimester with concurrent placenta accreta spectrum (PAS) disorders place obstetricians in a complex and delicate situation. ...However, there are limited data on this rare and dangerous condition. The objective of this research was to investigate and evaluate the clinical management strategies of this patient group.
The medical records of patients who were diagnosed and treated in our hospital from December 2005 and December 2015 were retrospectively reviewed.
A total of 29 patients were included in this analysis. A prenatal diagnosis was suspected in 8 (27.6%) patients, and the remaining 21 (72.4%) patients were diagnosed after pregnancy termination in the second trimester. In the subgroup with a prenatal diagnosis, a planned hysterotomy was performed in 7 patients who had total placenta previa and previous cesarean delivery. The remaining patient received medical termination. A subtotal hysterectomy was performed in 3 (10.3%) patients for life-threatening bleeding during hysterotomy, and the uterus was preserved with an in situ placenta in the remaining 5 patients. In the subgroup with a postnatal diagnosis, the implanted placenta remained partly or completely in situ in all 21 patients under informed consent. Ultimately, the implanted placenta remained partly or completely in situ in 26 (89.7%) patients in the two subgroups. With the application of adjuvant treatments, including uterine artery embolization and medication followed by curettage under ultrasound guidance, the implanted placenta was passed 76.6 (range: 19 to 192) days after termination. Uterus preservation was achieved in all 26 patients. The complications associated with conservative management included delayed postnatal hemorrhaging (2 cases, 7.7%), fever (6 cases, 23.1%), G1 transaminase disorder (4 cases, 15.4%), and myelosuppression (1 case, 3.8%). Seven women (26.9%) had a spontaneous pregnancy after conservative management, and no patient experienced recurrent PAS disorders.
Leaving the implanted placenta in situ is the preferred choice for patients with PAS disorders who underwent pregnancy termination in the second trimester and desired fertility preservation. Multiple adjuvant treatment modalities, either alone or in combination, may help to promote the passing or absorption of the implanted placenta under close monitoring.
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