Until now there has been no fundamental theory applicable for biodegradable metals (BMs). First, this paper optimizes the definition of BMs given in 2014. Second, the dual criteria of ...biodegradability and biocompatibility are proposed for BMs, and all metallic elements in the periodic table with accessible data are screened on the basis of these criteria. Regarding biodegradability, electrode potential, reactivity series, galvanic series, Pilling–Bedworth ratio, and Pourbaix diagrams are all adopted as parameters to classify the degradable and nondegradable nature of a material, especially in a physiological environment. Considering the biocompatibility at different levels, cellular biocompatibility, tissue biocompatibility, and human/clinical related biocompatibility parameters are put forward to comprehensively evaluate the biosafety of BMs. Third, for the material design of BMs, mechanical properties, chemical properties, physical properties and biological properties should be considered and balanced to guarantee that the degradation behavior of BMs match well with a tissue regeneration/repair procedure as the function of time and spatial location. Besides the selected metallic elements, some nonmetallic elements are selected as suitable alloying elements for BMs. Finally, five classification/research directions for future BMs are proposed: biodegradable pure metals, crystalline alloys, bulk metallic glasses, high entropy alloys, and metal matrix composites.
The fundamental theory of biodegradable metals are clarified in this review article, with the definition of biodegradable metals, biodegradability, and biocompatibility dual criteria for metallic elements in the periodic table being regarded as biodegradable metals. Key properties needed to be considered for materials design of biodegradable metals and future research and development directions for biodegradable metals are proposed.
This study employs a comprehensive methodology that involves a thorough review of the existing literature and case studies to understand the current state and trends in modern graphic design. It then ...delves into technical-aided design tools that graphic designers widely used to create interactive designs. The methodology also encompasses empirical analysis that entails conducting surveys and interviews with industry professionals and design experts. It seeks to identify the key elements and techniques that contribute to effective interaction design and discusses the importance of considering the user experience in the design process. Ultimately, this study aims to provide valuable insights into the ever-evolving world of graphic design and its intersection with technology. Aim: This article aims to improve the knowledge of modern graphic design and propose new ideas for graphic design by exploring the interaction function of modern graphic design based on technical-aided design software. Evaluation tool: The analysis is assessed using the Analysis of variance (ANOVA), Multivariable Logistic Regression, and Chi-Square tests. Results: The interaction of modern graphic design with technically aided design was examined, and it was found to improve modern graphic design significantly.
Electronic word-of-mouth (eWOM) is prevalent in today's lodging market and has potential to influence consumers’ decision making. This study investigated how the presence of online reviewers’ ...personal identifying information (PII) may affect consumers’ processing of ambivalent online hotel reviews and hotel booking intentions. The results of an experiment with a sample of 274 undergraduate students indicate that the presence of PII positively affects the perceived credibility of the online reviews. When coupled with ambivalent online reviews, the presence of PII significantly lowers consumers’ hotel booking intentions.
Background:
Knee osteoarthritis (KOA) is one of the most common chronic musculoskeletal disorders worldwide, for which exosomes derived from stem cells may provide an effective treatment.
Purpose:
To ...assess the effect of exosomes derived from human urine–derived stem cells (hUSCs) overexpressing miR-140-5p (miR means microRNA) on KOA in an in vitro interleukin 1β (IL-1β)–induced osteoarthritis (OA) model and an in vivo rat KOA model.
Study Design:
Controlled laboratory study.
Methods:
Exosomes derived from hUSCs (hUSC-Exos) were isolated and validated. The hUSCs were transfected with miR-140s using lentivirus, and exosomes secreted from such cells (hUSC-140-Exos) were collected. The roles of hUSC-Exos and hUSC-140-Exos in protecting chondrocytes against IL-1β treatment were compared by analyzing the proliferation, migration, apoptosis, and secretion of extracellular matrix (ECM) in chondrocytes. After vascular endothelial growth factor A (VEGFA) was identified as a target of miR-140, the mechanism by which VEGFA can mediate the beneficial effect of miR-140 on OA was investigated using small interfering RNA transfection or chemical drugs. The expression of VEGFA in cartilage and synovial fluid from patients with KOA was measured and compared with that of healthy controls. Surgery for anterior cruciate ligament transection and destabilization of the medial meniscus were performed on the knee joints of Sprague-Dawley rats to establish an animal model of OA, and intra-articular (IA) injection of hUSC-Exos or hUSC-140-Exos was conducted at 4 to 8 weeks after the surgery. Cartilage regeneration and subchondral bone remodeling were evaluated through histological staining and micro–computed tomography analysis.
Results:
Proliferation and migration ability were enhanced and apoptosis was inhibited in chondrocytes treated with IL-1β via hUSC-Exos, with the side effect of decreased ECM secretion. hUSC-140-Exos not only retained the advantages of hUSC-Exos but also increased the secretion of ECM by targeting VEGFA, including collagen II and aggrecan. Increased expression of VEGFA during the progression of KOA was also confirmed in cartilage and synovial fluid samples obtained from patients with OA. In the rat OA model, IA injection of hUSC-140-Exos enhanced cartilage regeneration and subchondral bone remodeling.
Conclusion:
Our results demonstrated the superiority of hUSC-Exos overexpressing miR-140-5p for treating OA compared with the hUSC-Exos. The effect of hUSC-140-Exos for suppressing the progression of KOA is in part mediated by VEGFA.
Clinical Relevance:
Exosomes derived from stem cells may provide a promising treatment for KOA, and our study can advance the related basic research.
Self-healing coating based on nanocontainers (NCs) has been emerging as a great strategy to improve the anticorrosion ability of susceptible metal substrate. However, all the research referred to ...such smart coating to date is focus on organic coating instead of metallic coating. To fill this gap, 2-mercaptobenzothiazole (MBT) loaded porous hollow SiO
2
NCs are synthesized and incorporated successfully into an electroless Ni coating on Mg alloy in this work. The surface morphologies and the loading properties of the NCs are characterized by scanning electron microscopy, transmission electron microscopy, ultraviolet–visible spectrophotometer, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The favorable performance of Ni coating after incorporation of NCs is demonstrated by potentiodynamic polarization (PDP), linear polarization, and electrochemical impedance spectroscopy. Based on the results of PDP test, the corrosion current density (
i
c
) of the MBT@NCs (MNCs)-engineered Ni coating reduces slightly from 6.4 to 5.4 μA cm
−2
after immersion in a corrosive media, while the value for MNCs-free coating increases by almost a factor of ten from 6.8 to 67.4 μA cm
−2
. Our findings demonstrate the possibility of using corrosion inhibitors loaded NCs to enhance the corrosion resistance of a metallic coating and give new perspectives for functionalization of a metallic coating with nanomaterials.
Magnetically actuated miniature soft robots are capable of programmable deformations for multimodal locomotion and manipulation functions, potentially enabling direct access to currently unreachable ...or difficult-to-access regions inside the human body for minimally invasive medical operations. However, magnetic miniature soft robots are so far mostly based on elastomers, where their limited deformability prevents them from navigating inside clustered and very constrained environments, such as squeezing through narrow crevices much smaller than the robot size. Moreover, their functionalities are currently restricted by their predesigned shapes, which is challenging to be reconfigured in situ in enclosed spaces. Here, we report a method to actuate and control ferrofluid droplets as shape-programmable magnetic miniature soft robots, which can navigate in two dimensions through narrow channels much smaller than their sizes thanks to their liquid properties. By controlling the external magnetic fields spatiotemporally, these droplet robots can also be reconfigured to exhibit multiple functionalities, including on-demand splitting and merging for delivering liquid cargos and morphing into different shapes for efficient and versatile manipulation of delicate objects. In addition, a single-droplet robot can be controlled to split into multiple subdroplets and complete cooperative tasks, such as working as a programmable fluidic-mixing device for addressable and sequential mixing of different liquids. Due to their extreme deformability, in situ reconfigurability and cooperative behavior, the proposed ferrofluid droplet robots could open up a wide range of unprecedented functionalities for lab/organ-on-a-chip, fluidics, bioengineering, and medical device applications.
Abstract
Recent studies have shed light on the cellular and molecular mechanisms that link subchondral bone remodelling and angiogenesis in knee osteoarthritis (OA). Type H vessels are a newly ...identified bone blood vessel characterized by high expression of CD31 and endomucin that are coupled with osteogenesis. Factors including mechanical loading, TGF-β1, platelet-derived growth factor type BB, the osteoprotegerin–RANK ligand–RANK system, osteopontin, mechanistic target of rapamycin, VEGF, stromal cell-derived factor l and prostaglandin E2 participate in the formation of type H vessels in osteoarthritic subchondral bone. In this review, we summarize the current understanding of type H vessels in knee OA, as well as the signalling pathways involved and potential therapeutic medicines. In future, the pathogenesis of knee OA could be further clarified by connecting type H vessels and the design of new disease-modifying osteoarthritis drugs. However, further experiments are needed to determine the upstream signals regulating type H vessel formation in osteoarthritic subchondral bone.
A dual organophotoredox/nickel-catalyzed reductive coupling of allenes with aldehydes has been developed for the rapid assembly of anti-homoallylic alcohols with high levels of regioselectivities ...(>20:1), diastereoselectivities (up to >20:1), and yields (up to 91%). The allylation was realized through a crucial π-allylnickel intermediate, which was obtained via insertion of allenes with a Ni–H intermediate. Moreover, γ,γ-disubstituted homoallylic alcohols with a quaternary stereocenter can also be prepared by this protocol.
•Waste heat recovery behavior of the RCS during driving cycle was investigated.•Four operating modes were defined to describe the operating process of the RCS under driving cycle.•The operating mode ...switching is the crucial reason for on-road inefficiency.•The dry and isentropic fluids are superior to the wet ones on the adaptability to unsteady ExGE.•The effects of the vapor parameters on RCT-E and power mode percentage are opposite.
The RCS (Rankine cycle system) used to recover the WHE (waste heat energy) from engines has been regarded as one of the most potential ways of achieving higher efficiency. However, it is of great challenge to keep the RCS still in good performance under driving cycle. This paper tries to reveal and explain its on-road inefficiency.
The operating process of the RCS under driving cycle was analyzed in advance. Afterwards, four basic operating modes were defined, including startup mode, turbine turning mode, power mode and protection mode. Then, a RCS model was established and operating performances of the RCS under an actual driving cycle were discussed based on this model. The results indicate that the on-road RCS-E (Rankine cycle system efficiency) is as low as 3.63%, which is less than half of the design RCS-E (7.77%) at the rated operating point. Despite the inevitable vapor state fluctuation, it is the operating mode switching during the driving cycle that leads to the on-road inefficiency. Further investigations indicate that the expander safety temperature and its safety margin affected by the working fluids, designed superheat degree and evaporating pressure are the main factors determining the operating mode switching. Finally, the effects of the working fluids, designed superheat degree and evaporating pressure on the operating mode switching and RC (Rankine cycle) efficiencies were profoundly investigated. The study shows that the dry and isentropic fluids are superior to the wet ones due to their less probabilities of droplets formation as a consequence of their saturated vapor characteristics. The effects of the vapor parameters on the RCT-E (Rankine cycle thermal efficiency) and operating mode switching are opposite. Therefore, in order to optimize the RCS, it would be better to take full consideration in reducing the operating mode switching, while pursuing the maximum RCT-E.
Rational design of non‐noble materials as highly efficient, economical, and durable bifunctional catalysts for oxygen evolution and reduction reactions (OER/ORR) is currently a critical obstacle for ...rechargeable metal‐air batteries. A new route involving S was developed to achieve atomic dispersion of Fe‐Nx species on N and S co‐decorated hierarchical carbon layers, resulting in single‐atom bifunctional OER/ORR catalysts for the first time. The abundant atomically dispersed Fe‐Nx species are highly catalytically active, the hierarchical structure offers more opportunities for active sites, and the electrical conductivity is greatly improved. The obtained electrocatalyst exhibits higher limiting current density and a more positive half‐wave potential for ORR, as well as a lower overpotential for OER under alkaline conditions. Moreover, a rechargeable Zn–air battery device comprising this hybrid catalyst shows superior performance compared to Pt/C catalyst. This work will open a new avenue to design advanced bifunctional catalysts for reversible energy storage and conversion devices.
In isolation: Atomically dispersed iron–nitrogen sites supported on hierarchical carbon nanotubes co‐decorated with nitrogen and sulfur are efficient electrocatalytic sites for oxygen‐evolution and ‐reduction reactions. The hybrid material demonstrates good stability in alkaline solutions, allowing incorporation into a rechargeable zinc–air battery as an air cathode.
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