β-type titanium (Ti) alloys have attracted a lot of attention as novel biomedical materials in the past decades due to their low elastic moduli and good biocompatibility. This article provides a ...broad and extensive review of β-type Ti alloys in terms of alloy design, preparation methods, mechanical properties, corrosion behavior, and biocompatibility. After briefly introducing the development of Ti and Ti alloys for biomedical applications, this article reviews the design of β-type Ti alloys from the perspective of the molybdenum equivalency (Moeq) method and DV-Xα molecular orbital method. Based on these methods, a considerable number of β-type Ti alloys are developed. Although β-type Ti alloys have lower elastic moduli compared with other types of Ti alloys, they still possess higher elastic moduli than human bones. Therefore, porous β-type Ti alloys with declined elastic modulus have been developed by some preparation methods, such as powder metallurgy, additive manufacture and so on. As reviewed, β-type Ti alloys have comparable or even better mechanical properties, corrosion behavior, and biocompatibility compared with other types of Ti alloys. Hence, β-type Ti alloys are the more suitable materials used as implant materials. However, there are still some problems with β-type Ti alloys, such as biological inertness. As such, summarizing the findings from the current literature, suggestions forβ-type Ti alloys with bioactive coatings are proposed for the future development.
The metastable pitting corrosion behavior of laser powder bed fusion (LPBF) produced Ti-6Al-4V is still unclear. Therefore, this work investigated the metastable pitting corrosion of LPBF-produced ...Ti-6Al-4V in Hank’s solution by electrochemical methods. The LPBF-produced sample (dominant by α′ phase in the microstructure) shows a higher frequency of pit nucleation than the annealed counterpart (composed by α + β dual phase). The passive films formed on the LPBF-produced sample exhibit a higher flux of oxygen vacancies, resulting in the absorption of more aggressive ions (e.g., Cl-) thereby producing more cation vacancies. The condensation of excessive cation vacancies contributes to the pit nucleation.
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•Laser powder bed fusion (LPBF) produced Ti–6Al–4 V alloy was used as the sample.•Corrosion behavior of the LPBF-produced sample was investigated in Hank’s solution.•The LPBF-produced Ti-6Al-4 V shows frequent metastable pitting corrosion.•The flux of oxygen vacancy is large in the passive film of LPBF-produced Ti-6Al-4 V.•Redundant vacancies assemble and condense into a void at metal/film interface.
The aryl‐to‐vinyl nickel 1,4‐migration (1,4‐Ni migration) reaction has been reported for the first time. The generated alkenyl Ni species undergo a reductive coupling reaction with unactivated ...brominated alkanes affording a series of trisubstituted olefins. This tandem reaction exhibits mild conditions, a broad substrate scope, high regioselectivity, and excellent Z/E stereoselectivity. A series of controlled experiments have shown that the critical 1,4‐Ni migration process is reversible. In addition, the alkenyl nickel intermediates obtained after migration are highly Z/E stereoselective and do not undergo Z/E isomerization. The obtained trace isomerization products are caused by the instability of the product.
The 1,4‐nickel migration process from aryl to alkenyl groups is now reported for the first time. The alkenyl nickel intermediates generated by this highly stereoselective migration process can be coupled with brominated alkanes to form multisubstituted olefins. The current method provides a new and efficient approach for the synthesis of Z/E olefins with high stereoselectivity.
This work investigated the metastable pitting corrosion mechanism of laser powder bed fusion (LPBF) produced Ti–6Al–4V. The passive films of samples were produced by potentiostatic polarization in ...NaCl solutions with different concentrations, and electrochemical measurements were employed to understand the influence of Cl- on the characteristics of passive films. The frequency of pitting nucleation and the pit dimension increase with increased Cl- concentration. The attack of Cl- promotes the dissolution of passive films. A higher density of oxygen vacancies is produced in passive film because of the ingressive Cl-, resulting in the condensation of voids and pitting corrosion.
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•A Ti-6Al-4V alloy was fabricated by laser powder bed fusion (LPBF) method.•Metastable pitting corrosion of the samples was investigated in NaCl solutions.•Cl- suppresses the formation of passive film formed on LPBF-produced sample.•The passive film has higher flux of oxygen vacancies in 10 wt% NaCl solution.•The condensation of cation-anion-vacancy associations triggers voids and pitting.
Shuxuening injection (SXNI), a popular herbal medicine, is an extract of Ginkgo biloba leaves (GBE), and is used to treat ischemic stroke (IS) in China. However, its specific active ingredients and ...molecular mechanisms in IS remain unclear.
Aim of the study: The purpose of the research is to identify the main active ingredients in GBE and explore its molecular mechanisms in the treatment of IS.
The main active components of GBE were discerned through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis (TCMSP), Traditional Chinese Medicine Integrated Database (TCMID), Bioinformatics Analysis Tool for Molecular Mechanism of Traditional Chinese Medicine (BATMAN-TCM) database, and absorption, distribution, metabolism and excretion (ADME) analysis. The targets related to IS were obtained using Genecards, Online Mendelian Inheritance in Man (OMIM), Therapeutic Target Database (TTD), and Disgenet. We discovered an intersection of genes. Subsequently, protein-protein interaction (PPI) networks were constructed with Cytoscape 3.7.1 and the String database. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to analyze the intersection of targets via the Database for Annotation, Visualization, and Integrated Discovery (DAVID) 6.8. Built on the above analysis, we made a Compound-Target-Pathway (C-T-P) network. Autodock Vina was used for molecular docking analysis. Maestro 11.9 was used to calculate the root-mean-square deviation (RMSD). Animal experiments were performed to verify the core targets. Triphenyl tetrazolium chloride (TTC) staining was used to calculate the infarct volume in rats. Hematoxylin-eosin (HE) staining was employed to observe the morphology of hippocampal neuron cells. RT-qPCR was applied to detect relative mRNA levels, and protein expression was determined using Western blotting.
Molecular docking showed that PTGS2, NOS3 and CASP3 docked with small molecule compounds. According to RT-qPCR and Western blotting, mRNA and protein expression of PTGS2 and CASP3 were up-regulated (P < 0.05), and mRNA and protein levels of NOS3 were down-regulated (P < 0.05).
SXNI can treat IS through multiple targets and routes, and reduce the apoptosis of neuron cells in brain tissue by inhibiting inflammation and regulating the level of oxidative stress, thereby protecting rats brain tissue.
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Background:
High prevalence of smartphone addiction among medical students may contribute to adverse physical and mental health outcomes.
Aim:
To estimate the prevalence of smartphone addiction, and ...explore the influencing factors and related mental health symptoms of smartphone addiction among Asian medical students.
Design:
Systematic review and meta-analysis.
Methods:
PubMed (MEDLINE), the Cochrane Central Register of Controlled Trials, and EMBASE were searched for relevant literature from the inception to September 10, 2021. Using Stata software 11.0, the meta-analysis of prevalence and the influencing factors of smartphone addiction were determined with 95% confidence intervals.
Results:
Nineteen articles, published between 2014 and 2019, were included, producing medical student studies from seven different Asian countries. The included studies were conducted in India (n = 11) and Malaysia (n = 3), with China, Saudi Arabia, Turkey, Nepal, and Iran each contributing one study. Among a total of 5,497 medical students, the participants included 3,214 females, of whom 2,181 were medical students with smartphone addiction. The prevalence of smartphone addiction among Asian medical students was 41.93% (95% CI 36.24%, 47.72%). The influencing factors of smartphone addiction among medical students included gender, duration of smartphone use, smartphone function, and marital status. Ten studies (52.63%) explored related mental health symptoms of smartphone addiction among Asian medical students. Smartphone addiction was positively correlated with poor sleep quality (r = .17–.31), stress (r = .30–.40), anxiety, depression, neuroticism, and general health among Asian medical students.
Conclusion:
Smartphone addiction is highly prevalent among Asian medical students. Smartphone addiction may adversely affect mental health, resulting in sleep disturbance, stress, anxiety, depression, and neuroticism. It is necessary to take appropriate precautionary actions and interventions to prevent smartphone overuse among medical students.
Direct conversion of earth-abundant methane into value-added chemicals under mild conditions is an attractive technology in response to the increasing industrial demand of feedstocks and worldwide ...appeal of energy conservation. Exploring advanced low-temperature C–H activation catalysts and reaction systems is the key to converting methane in a direct and mild manner. The recently developed reaction processes operated at low-temperature thermocatalysis systems or driven in electro- and photocatalysis systems shine light on the way to achieve efficient methane conversion with much economical energy input. In this review, we summarize the typical catalytic processes employed in these reaction systems and in particular highlight the potential heterogeneous catalysts with noteworthy C–H activation performance. We also present the progress along with our perspectives on catalyst design, theoretical simulations, the choice of reaction condition, and the method of reaction product analysis to encourage more viable technology for low-temperature methane conversion in the future.
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Direct low-temperature methane conversion is a promising route for the chemical industry to access various basic feedstocks in the future. Developing such technology to displace the traditional energy-intensive syngas pathway has attracted increasing interest. A key for this technology is to seek advanced catalytic systems that enable efficient C–H activation along with a controllable reaction kinetics process. Therefore, it is important to take advantage of the various types of catalytic materials to effectively transform thermal, electric, and photonic energies into the driving forces for C–H activation. In this review, we present recent experimental and theoretical progress in the design of direct low-temperature methane conversion catalysts as well as the C–H activation mechanism in thermocatalysis, electrocatalysis, and photocatalysis systems to encourage more viable technologies for this challenging subject.
Direct methane conversion into value-added products at low temperature is an attractive technology for the chemical industry. However, because of the stable molecular structure and high C–H bond energy, methane conversion is a very tough process and is regarded as the “holy grail” in catalysis. Through the rational design of catalysts and the involvement of electro- and photoactivation processes, low-temperature C–H activation and methane conversion can be realized.
RuO2 is considered as the state‐of‐the‐art electrocatalyst for the oxygen evolution reaction (OER) in acidic media. However, its practical application is largely hindered by both the high reaction ...overpotential and severe electrochemical corrosion of the active centers. To overcome these limitations, innovative design strategies are necessary, which remains a great challenge. Herein, robust interface Ru centers between RuO2 and graphene, via a controllable oxidation of graphene encapsulating Ru nanoparticles, are presented to efficiently enhance both the activity and stability of the acidic OER. Through precisely controlling the reaction interface, a much lower OER overpotential of only 227 mV at 10 mA cm−2 in acidic electrolyte, compared with that of 290 mV for commercial RuO2, but a significantly higher durability than the commercial RuO2, are achieved. Density functional theory (DFT) calculations reveal that the interface Ru centers between the RuO2 and the graphene can break the classic scaling relationships between the free energies of HOO* and HO* to reduce the limiting potential, rendering an enhancement in the intrinsic OER activity and the resistance to over‐oxidation and corrosion for RuO2.
The robust interface Ru centers between RuO2 and graphene are found to boost both activity and stability for the acidic oxygen evolution reaction (OER), exhibiting a much lower OER overpotential of only 227 mV at 10 mA cm−2 compared with that of 290 mV for commercial RuO2 but a significantly higher durability than the commercial RuO2.
Rad transition: The combination of transition‐metal‐catalyzed CH activation and a NHPI‐initiated radical process is essential for the title transformation. The neutral conditions and the ideal ...oxidant, molecular oxygen, make this hydroxylation environmentally friendly and practical. NHPI=N‐hydroxyphthalimide.
Summary Background The current influenza pandemic calls for a safe and effective vaccine. We assessed the safety and immunogenicity of eight formulations of 2009 pandemic influenza A H1N1 vaccine ...produced by ten Chinese manufacturers. Methods In this multicentre, double-blind, randomised trial, 12 691 people aged 3 years or older were recruited in ten centres in China. In each centre, participants were stratified by age and randomly assigned by a random number table to receive one of several vaccine formulations or placebo. The study assessed eight formulations: split-virion formulation containing 7·5 μg, 15 μg, or 30 μg haemagglutinin per dose, with or without aluminium hydroxide adjuvant, and whole-virion formulation containing 5 μg or 10 μg haemagglutinin per dose, with adjuvant. All formulations were produced from the reassortant strain X-179A (A/California/07/2009-A/PR/8/34). We analysed the safety (adverse events), immunogenicity (geometric mean titre GMT of haemagglutination inhibition antibody), and seroprotection (GMT ≥1:40) of the formulations. Analysis was by per protocol. Two sites registered their trial with ClinicalTrials.gov , numbers NCT00956111 and NCT00975572 . The other eight studies were registered with the State Food and Drug Administration of China. Findings 12 691 participants received the first dose on day 0, and 12 348 participants received the second dose on day 21. The seroprotection rate 21 days after the first dose of vaccine ranged from 69·5% (95% CI 65·9–72·8) for the 7·5 μg adjuvant split-virion formulation to 92·8% (91·9–93·6) for the 30 μg non-adjuvant split-virion formulation. The seroprotection rate was 86·5% (796 of 920; 84·1–88·7) in recipients of one dose of the 7·5 μg non-adjuvant split-virion vaccine compared with 9·8% (140 of 1432; 8·3–11·4) in recipients of placebo (p<0·0001). One dose of the 7·5 μg non-adjuvant split-virion vaccine induced seroprotection in 178 of 232 children (aged 3 years to <12 years; 76·7%, 70·7–82·0), 211 of 218 adolescents (12 years to <18 years; 96·8%, 93·5–98·7), 289 of 323 adults (18–60 years; 89·5%, 85·6–92·6), and 118 of 147 adults older than 60 years (80·3%, 72·9–86·4), meeting the European Union's licensure criteria for seroprotection in all age-groups. In children, a second dose of the 7·5 μg formulation increased the seroprotection rate to 97·7% (215 of 220, 94·8–99·3). Adverse reactions were mostly mild or moderate, and self-limited. Severe adverse effects occurred in 69 (0·6%, 0·5–0·8) recipients of vaccine compared with one recipient (0·1%, 0–0·2) of placebo. The most common severe adverse reaction was fever, which occurred in 25 (0·22%; 0·14–0·33) recipients of vaccine after the first dose and four (0·04%; 0·01–0·09) recipients of vaccine after the second dose compared with no recipients of placebo after either dose. Interpretation One dose of non-adjuvant split-virion vaccine containing 7·5 μg haemagglutinin could be promoted as the formulation of choice against 2009 pandemic influenza A H1N1 for people aged 12 years or older. In children (aged <12 years), two 7·5 μg doses might be needed. Funding Sinovac Biotech, Hualan Biological Bacterin, China National Biotec Group, Beijing Tiantan Biological Products, Changchun Institute of Biological Products, Changchun Changsheng Life Sciences, Jiangsu Yanshen Biological Technology Stock, Zhejiang Tianyuan Bio-Pharmaceutical, Lanzhou Institute of Biological Products, Shanghai Institute of Biological Products, and Dalian Aleph Biomedical.
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