Sphingosine-1-phosphate (S1P) signaling is being increasingly recognized as a strong modulator of immune cell migration and endothelial function. Fingolimod and other S1P modulators in ischemic ...stroke treatment have shown promise in emerging experimental models and small-scale clinical trials. In this article, we will review the current knowledge of the role of S1P signaling in brain ischemia from the aspects of inflammation and immune interventions, sustaining endothelial functions, regulation of blood-brain barrier integrity, and functional recovery. We will then discuss the current and future therapeutic perspectives of targeting S1P for the treatment of ischemic stroke. Mechanism studies would help to bridge the gap between preclinical studies and clinical practice. Future success of bench-to-bedside translation shall be based on in depth understanding of S1P signaling during stroke and on the ability to have a fine temporal and spatial regulation of the signal pathway.
Objective
This systematic review aims to analyze existing literature of the effects of transcranial direct current stimulation (tDCS) on motor skills learning of healthy adults and discuss the ...underlying neurophysiological mechanism that influences motor skills learning.
Methods
This systematic review has followed the recommendations of the Preferred Reporting Items for Systematic reviews and Meta-Analyses. The PubMed, EBSCO, and Web of Science databases were systematically searched for relevant studies that were published from database inception to May 2022. Studies were included based on the Participants, Intervention, Comparison, Outcomes, and Setting inclusion strategy. The risk of bias was evaluated by using the Review manager 5.4 tool. The quality of each study was assessed with the Physiotherapy Evidence Database (PEDro) scale.
Results
The electronic search produced 142 studies. Only 11 studies were included after filtering. These studies performed well in terms of distribution, blinding availability and selective reporting. They reported that tDCS significantly improved motor skills learning. The main outcomes measure were the improvement of the motor sequence tasks and specific motor skills. Nine studies showed that tDCS interventions reduced reaction time to complete motor sequence tasks in healthy adults and two studies showed that tDCS interventions improved golf putting task performance.
Conclusion
The included studies showed that tDCS can help healthy adults to improve the motor skills learning by activating different brain regions, such as the primary motor cortex, left dorsolateral prefrontal cortex and right cerebellum. However, the number of included studies was limited, and the sample sizes were small. Therefore, more studies are urgently needed to validate the results of current studies and further explore the underlying neurophysiological mechanisms of tDCS in the future.
Background
With the improvement in diagnostic imaging, perioperative care and surgical technique, the indications and complexity of liver resections have developed. However, the surgical indications ...remain controversial especially for some complex or advanced hepatocellular carcinomas. This study was designed to evaluate the concordance between hepatectomy recommendations proposed by Watson for Oncology, a cognitive technology providing decision support, and those determined by surgeons in our center for patients with hepatocellular carcinoma.
Methods
We retrospectively reviewed 243 patients with hepatocellular carcinoma who were recommended for surgical treatment and received hepatectomy between 2008 and 2016 at the Zhujiang Hospital of Southern Medical University. Watson for Oncology classified the treatment options into three categories: recommended, for consideration and not recommended. Treatment recommendations were considered concordant if the hepatectomy recommendations were designated “recommended” or “for consideration” by Watson for Oncology. The factors potentially affecting concordance rate were also analyzed in our study.
Results
The hepatectomy recommendations of 174 patients were concordant. There were significant differences in the coincidence rate between concordant group and discordant group considering tumor numbers (
P
= 0.006), extension of hepatectomy (
P
= 0.009) and BCLC staging system (
P
< 0.001). Lower degrees of concordance were observed in patients with multiple tumors, major hepatectomy and portal hypertension by using logistic regression analysis (OR = 0.309,
P
= 0.004; OR = 0.384,
P
= 0.004; and OR = 0.376,
P
= 0.022, respectively).
Conclusion
The concordance between Watson for Oncology and surgeons’ hepatectomy recommendation for hepatocellular carcinoma was only 72%. Differences in practice patterns for HCC between the USA (where Watson for Oncology was calibrated) and China may be the major cause of discordance. Watson for Oncology still requires further improvement and localization to be widely applied in China.
Al-air battery is a promising alternative to electrochemical storage systems because of their high energy density and low cost. However, the hydrogen evolution corrosion in alkaline electrolytes is a ...major obstacle before this technology can be commercially viable. In this paper, three polyelectrolytes as corrosion inhibitors for pure Al anodes in KOH electrolytes are investigated by electrochemical methods, hydrogen evolution rate (HER) tests, weight loss measurements, and surface characterization. The Attenuated Total internal Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and theoretical simulation results show that all the polyelectrolytes can be adsorbed on Al to form a protective barrier against the corrosive species. In particular, poly(allylamine) (PAH) exhibits the highest corrosion inhibition efficiency. Furthermore, galvanostatic discharge measurement reveals that the Al-air battery in PAH electrolyte exhibits the highest specific discharge capacity (1495.2 mA h g−1). Computational analysis shows that the inhibition performance depends on the frontier molecular orbital energy and adsorption energy.
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•Polyelectrolytes are assessed as corrosion inhibitors for the Al-air battery.•The anticorrosion efficiency follows the order of PAH > PAA > PSS.•PAH would form the most compact protective layer in the near-surface region.•The adsoption energy rather than ΔE would determine the anti-corrosion efficiency.
Acyclic guanosine analogues, a class of widely used antiviral drugs, can cause chronic toxicity and virus resistance. Therefore, it is essential to establish rapid and accurate methods to detect ...acyclic guanosine analogues. In this study, five acyclic guanosine analogues (acyclovir, famciclovir, ganciclovir, penciclovir, and valaciclovir) were used as positive targets to obtain broad-spectrum aptamers through Capture-SELEX technology. Real-time quantitative PCR (Q-PCR) was used to monitor the aptamer SELEX process. After the sixteen rounds of selection against mixed targets, sequences were obtained by high-throughput sequencing (HTS). Furthermore, a broad-spectrum aptamer, named CIV6, was found as the higher performance aptamer that was suitable for five acyclic guanosine analogues by graphene oxide (GO) polarization and fluorescence assay. Finally, the aptamer CIV6 was used to construct GO fluorescence assay to detect five acyclic guanosine analogues. The limits of detection (LOD) of acyclovir, famciclovir, ganciclovir, penciclovir, and valaciclovir were 0.48 ng·mL
−1
, 0.53 ng·mL
−1
, 0.50 ng·mL
−1
, 0.56 ng·mL
−1
, and 0.38 ng·mL
−1
, respectively.
Graphical abstract
Biodegradable magnesium (Mg)-based alloys have aroused great concern owing to their promising characteristics as temporary implants for orthopedic application. But their undesirably rapid corrosion ...rate under physiological conditions has limited the actual clinical application. This study reports the use of a novel biomimetic polyelectrolyte multilayer template, based on polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) via layer-by-layer (LbL) assembly, to improve the corrosion resistance of the alloy. Surface characterization techniques (field-emission scanning electron microscopy, Fourier transform infrared (FTIR) spectrophotometer and X-ray diffractometer) confirmed the formation of biomineralized Ca–P coating on AZ31 alloy. Both hydrogen evolution and electrochemical corrosion tests demonstrated that the corrosion protection of the polyelectrolyte-induced Ca–P coating on AZ31 alloy. The formation mechanism of biomineralized Ca–P coating was proposed.
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•A novel LbL assembled template induces a compact and thick Ca–P coating.•(PVP/PAA)5.5 template improves the binding force of the Ca–P coating.•The templates-induced Ca–P coating exhibits a good corrosion protection for Mg alloy.•Free PAA and PVP may go against the nucleation and growth of the Ca–P crystals.•(PVP/PAA)5.5 template is beneficial to the formation of the crystalline Ca–P coating.
An l-cysteine-bioinspired calcium phosphate (Ca-P) coating is prepared upon magnesium alloy AZ31 in a water bath at 60 °C. FE–SEM, FTIR, XRD, electrochemical characterization, hydrogen evolution ...tests and XPS were used to evaluate the microstructure, chemistry and corrosion performance of the samples. Results indicate that l-cysteine promotes the nucleation process of the coating and significantly increases its thickness. This can be attributed to the complexation of the carboxyl group and mercapto group of l-cysteine with calcium ions. Indeed, the obtained Ca-P coating possesses higher corrosion resistance than that prepared in l-cysteine-free bath.
•The multilayers loaded with GS could be constructed on Ti alloys by LbL assembly.•The electrostatic forces in the multilayers could be demonstrated by XPS results.•The multilayers showed ...antibacterial property and a sustained release of GS.
To reduce the bacteria-associated infection for the Ti implant, an antibacterial coating composed of gentamicin (GS) and polyacrylic acid (PAA) was constructed using layer-by-layer (LbL) assembly technique. The surface morphology and chemical composition of the obtained multilayers were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The plate counting method was employed to evaluate the antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) of the coating. The results revealed that the drug loaded multilayers could inhibit the growth of bacteria on the Ti substrate.
Zinc calcium phosphate (Zn–Ca–P) coating and cerium-doped zinc calcium phosphate (Zn–Ca–Ce–P) coating were prepared on AZ31 magnesium alloy. The chemical compositions, morphologies and corrosion ...resistance of coatings were investigated through energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), electron probe micro-analysis (EPMA) and scanning electron microscopy (SEM) together with hydrogen volumetric and electrochemical tests. The results indicate that both coatings predominately contain crystalline hopeite (Zn3(PO4)2·4H2O), Mg3(PO4)2 and Ca3(PO4)2, and traces of non-crystalline MgF2 and CaF2. The Zn–Ca–Ce–P coating is more compact than the Zn–Ca–P coating due to the formation of CePO4, and displays better corrosion resistance than the Zn–Ca–P coating. Both coatings protect the AZ31 Mg substrate only during an initial immersion period. The micro-galvanic corrosion between the coatings and their substrates leads to an increase of hydrogen evolution rate (HER) with extending the immersion time. The addition of Ce promotes the homogenous distribution of Ca and formation of hopeite. The Zn–Ca–Ce–P coating has the potential for the primer coating on magnesium alloys.
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This work reports the design and preparation of novel organic (polyvinyl alcohol, PVA)-inorganic (neodymium nitrate, Nd(NO3)3) hybrid coatings on micro-arc oxidation (MAO) coating for ...magnesium (Mg) alloy corrosion protection. X-ray diffractometer, X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy, field emission scanning electron microscope, Energy Dispersive X-ray spectrometer and surface roughness were applied to characterize the chemical composition and surface morphology of the coatings. The corrosion resistance of the coatings was evaluated by electrochemical and salt spray tests. The results suggested that the formation of PVA-Nd3+ and PVA-Mg2+ complexes promoted the enrichment of Nd3+ on the surface, and thereby improved the sealing quality and compactness of the coating. Interestingly, when the coating was damaged, the Nd3+ ions were transformed to their carbonates and covered the active sites, and thus exhibiting self-healing function. Further, the corrosion resistance of PVA-Nd3+ modified MAO composite coating on AZ31 Mg alloy was improved.
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