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▶ Using adult rabbits as animal models, we investigate the effect of Ca-def HA coating on the degradation behavior and bone response of the Mg–Zn–Ca alloy. ▶ In vivo degradation of ...the Ca-def HA coating and magnesium substrate occurs almost simultaneously, and in vivo valid life of this coating is about 8 weeks. ▶ The Ca-def HA coating has good osteoconductivity and is in favor of the formation of more new bone around the coated magnesium implants.
In present paper, an in vivo study was carried out on uncoated and calcium-deficient hydroxyapatite (Ca-def HA) coated Mg–Zn–Ca alloy to investigate the effect of Ca-def HA coating on the degradation behavior and bone response of magnesium substrate. Magnesium alloy rods were implanted into rabbit femora and evaluated during 24 weeks implantation. The characterization of both implants indicates that in vivo degradation of the Ca-def HA coating and magnesium substrate occurs almost simultaneously, and in vivo valid life of the coating is about 8 weeks, after that the degradation rate of the coated implants increases obviously. The main reasons for the Ca-def HA coating degradation can be attributed to its reaction with body fluid and the substitution of Mg
2+ ions in Ca-def HA. Histopathological examinations show that the Ca-def HA coating has good osteoconductivity and is in favor of the formation of more new bone on the surface of magnesium alloy. So the Ca-def HA coating could not only slow down in vivo degradation of magnesium alloy but also improve its bone response.
Composite coatings with hydroxyapatite (HA), octacalcium phosphate (OCP) in electrochemical deposition (ED) layers and MgO, Mg3 (PO4 )2 in microarc oxidation (MAO) layers were prepared by ED and MAO ...on Mg-Zn-Ca alloy to improve the corrosion resistance and bone response. Substrates and coated samples were implanted in the femur shaft of rabbits to observe in vivo degradation behavior during 50 weeks. Results showed that the degradation rate of the substrates was much faster than the coated at 8, 12 weeks and became close to the coated at 18 weeks postoperatively. The composite coatings prevented the substrate from rapid release of magnesium ions at the interface and gradually degraded at the same time. The composite coatings induced more newly formed bone tissue and faster bone response. Overall, reduced degradation rate and improved bone response were achieved by the composite coatings. Thus, the composite coatings on Mg-Zn-Ca alloy are promising for clinical application in the future.
Extracellular vesicles (EVs) or exosomes are nanosized extracellular particles that contain proteins, DNA, non-coding RNA (ncRNA) and other molecules, which are widely present in biofluids throughout ...the body. As a key mediator of intercellular communication, EVs transfer their cargoes to target cells and activate signaling transduction. Increasing evidence shows that ncRNA is involved in a variety of pathological and physiological processes through various pathways, particularly the inflammatory response. Macrophage, one of the body's "gatekeepers", plays a crucial role in inflammatory reactions. Generally, macrophages can be classified as pro-inflammatory type (M1) or anti-inflammatory type (M2) upon their phenotypes, a phenomenon termed macrophage polarization. Increasing evidence indicates that the polarization of macrophages plays important roles in the progression of cardiovascular diseases (CVD). However, the role of exosomal ncRNA in regulating macrophage polarization and the role of polarized macrophages as an important source of EV in CVD remains to be elucidated. In this review, we summarize the role and molecular mechanisms of exosomal-ncRNA in regulating macrophage polarization during CVD development, focusing on their cellular origins, functional cargo, and their detailed effects on macrophage polarization. We also discuss the role of polarized macrophages and their derived EV in CVD as well as the therapeutic prospects of exosomal ncRNA in the treatment of CVD.
•A statistical analysis of 1207 marine accidents worldwide from 2010 to 2019.•A critical literature review on previous studies on marine accident severity.•A study on the relationship between the ...influencing factors and accident severity.•Provision of recommendations for the improvement of maritime safety.
This study aims to explore the relationship between the severity of marine accidents and influencing factors. An ordered logistic regression model is used to reflect the relationship between these factors and the severity of marine accidents using the worldwide accident investigation reports in the period of 2010–2019. The obtained results show that the marine accident severity is positively associated with sinking accidents, far away from port, strong wind, heavy sea, strong current and/or good visibility. With respect to ship types, fishing vessels, yachts and sailing vessels, and other ship types are the ship types most involved in accidents of higher severity. The severity level is higher for ships having incomplete or invalid seafarers’ certificates, inadequate ship manning, incomplete or invalid ship certificates and/or over 30 years of age. Seafarers with poor theoretical knowledge and less sea experience are more likely to be involved in accidents of serious consequences. Small water depth and ship types such as chemical tankers, oil tankers, container ships and/or bulk carriers are negatively related to the accident severity. The results of this study can be used to assist the relevant maritime authorities in taking effective measures of preventing the occurrence of serious marine accidents.
Bone drilling is a routine operation in surgeries, such as neurosurgery and orthopedics. However, the excessive drilling temperature may cause severe thermal damage to the bone tissue. Therefore, the ...drilling temperature determination of bone tissue can reduce the harm caused by thermal damage. A time-varying temperature field simulation model of bone drilling was set up by ABAQUS software in this paper, based on the Johnson-Cook model. Then it was validated with experiments by drilling cortical bone of fresh bovine shaft of the femur. The relative error between the experimental values and the theoretical values within 7.67% showed a good consistency. Furthermore, the aging factor is also considered to evaluate the temperature field of bone drilling. The results showed that the drilling temperature near the bone-drill area increased significantly. The drilling temperature of cortical bone decreases sharply with the radial distance and exhibits a hysteresis lag in the axial distribution. The aging factor mainly affects the peak of drilling temperature. The peak of drilling temperature tends to increase with age. The peak drilling temperature in the elderly (70y) was up to 6.8% higher than that in the young (20y), indicating that the elderly is more prone to excessive drilling temperature. Therefore, special attention should be paid to the temperature control of elderly bone tissue.
Legionella is the causative agent of Legionnaires' disease, and hot springs are a major source of outbreaks of this disease. It is important from a public health perspective to survey hot spring ...environments for the presence of Legionella.
Prospective surveillance of the extent of Legionella pollution was conducted at three hot spring recreational areas in Beijing, China in 2011. Pulsed-field gel electrophoresis (PFGE) and sequence-based typing (SBT) were used to describe the genetic polymorphism of isolates. The intracellular growth ability of the isolates was determined by interacting with J774 cells and plating the dilutions onto BCYE agar plates.
Overall, 51.9% of spring water samples showed Legionella-positive, and their concentrations ranged from 1 CFU/liter to 2,218 CFU/liter. The positive rates of Legionella were significantly associated with a free chlorine concentration of ≥0.2 mg/L, urea concentration of ≥0.05 mg/L, total microbial counts of ≥400 CFU/ml and total coliform of ≥3 MPN/L (p<0.01). The Legionella concentrations were significantly associated with sample temperature, pH, total microbial counts and total coliform (p<0.01). Legionella pneumophila was the most frequently isolated species (98.9%), and the isolated serogroups included serogroups 3 (25.3%), 6 (23.4%), 5 (19.2%), 1 (18.5%), 2 (10.2%), 8 (0.4%), 10 (0.8%), 9 (1.9%) and 12 (0.4%). Two hundred and twenty-eight isolates were analyzed by PFGE and 62 different patterns were obtained. Fifty-seven L. pneumophila isolates were selected for SBT analysis and divided into 35 different sequence types with 5 main clonal groups. All the 57 isolates had high intracellular growth ability.
Our results demonstrated high prevalence and genetic polymorphism of Legionella in springs in Beijing, China, and the SBT and intracellular growth assay results suggested that the Legionella isolates of hot spring environments were pathogenic. Improved control and prevention strategies are urgently needed.
Abstract C 15 H 14 F 3 NO 3 , monoclinic, P 2 1 (no. 4), a = 5.0637(5) Å, b = 19.1061(19) Å, c = 7.4883(6) Å, β = 95.666(9)°, V = 720.94(12) Å 3 , Z = 2, R gt ( F ) = 0.0463, wR ref ( F 2 ...) = 0.1036, T = 294.8(6) K.
A novel AB5-alloy oxide/graphene composite has been fabricated through a facile mixing of commercial oxidized AB5-alloy and graphene as anode materials for lithium ion batteries. Electrochemical ...measurements show that the composite delivers an initial discharge capacity of 1639.7mAhg−1 and maintains a high reversible capacity of 418.2mAhg−1 up to 180 cycles. The enhanced cycling stability could be attributed to the fact that AB5-alloy oxide/graphene composite can accommodate large volume change during cycling and maintain good electronic contact.
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