Effect of nano-CaO particle on the microstructure,mechanical properties and corrosion behavior of lean Mg-1Zn alloy

The effects of nano-CaO contents on the microstructure,mechanical properties and corrosion resistance of lean Mg-1Zn alloy were investigated.The results showed that the addition of nano-CaO significantly refined the grain size and improved mechanical properties of the Mg-1Zn alloy.At the same time,CaO reacted with molten Mg in situ to form nano-MgO,whose corrosion product in SBF solution was the same with the degradation product of Mg matrix,resulting in the enhanced compactness of the Mg(OH)_(2) layer and reduced corrosion rate of matrix.The Mg-1Zn alloy had lower corrosion resistance due to excessively large grain size and shedding of corrosion products.The composite with 0.5 wt.%CaO had the best corrosion resistance with a weight loss of 9.875 mg·y^(-1)·mm^(-2)due to the small number of Ca_(2)Mg_(6)Zn_(3) phase and suitable grain size.While for composites with high content of CaO(0.7 wt.%and 1.0 wt.%),they had lower corrosion resistance due to the coexistence of large number of Ca_(2)Mg_(6)Zn_(3) and Mg_(2)Ca at grain boundaries,especially for 1.0 wt.%CaO composite,resulting from the strong micro-galvanic corrosion.

Restoration of space-variant blurred image based on motion-blurred target segmentation

In imaging on moving target, it is easy to get space- variant blurred image. In order to recover the image and gain recognizable target, an approach to recover the space-variant blurred image is presented based on image segmentation. Be- cause of motion blur＇s convolution process, the pixels of observed image＇s target and background will be displaced and piled up to produce two superposition regions. As a result, the neighbor- ing pixels in the superposition regions will have similar grey level change. According to the pixel＇s motion-blur character, the target＇s blurred edge of superposition region could be detected. Canny operator can be recurred to detect the target edge which parallels the motion blur direction. Then in the segmentation process, the whole target image which has the character of integral convolution between motion blur and real target image can be obtained. At last, the target image is restored by deconvolution algorithms with adding zeros. The restoration result indicates that the approach can effectively solve the kind of problem of space-variant motion blurred image restoration.

MicroRNA-132 in the Adult Dentate Gyrus is Involved in Opioid Addiction Via Modifying the Differentiation of Neural Stem Cells

MicroRNA-132(miR-132), a small RNA that regulates gene expression, is known to promote neurogenesis in the embryonic nervous system and adult brain.Although exposure to psychoactive substances can increase miR-132 expression in cultured neural stem cells(NSCs)and the adult brain of rodents, little is known about its role in opioid addiction. So, we set out to determine the effect of miR-132 on differentiation of the NSCs and whether this effect is involved in opioid addiction using the rat morphine self-administration(MSA) model. We found that miR-132 overexpression enhanced the differentiation of NSCs in vivo and in vitro. Similarly, speci?c overexpression of miR-132 in NSCs of the adult hippocampal dentate gyrus(DG) during the acquisition stage of MSA potentiated morphine-seeking behavior. These ?ndings indicate that miR-132 is involved in opioid addiction,probably by promoting the differentiation of NSCs in the adult DG.

Fabrication of superstable gold nanorod-carbon nanocapsule as a molecule loading material

In this work, we fabricated a monodisperse nanocomposite by coating gold nanorods(Au NRs) with a layer of biocompatible, stable carbon, obtaining Au NR@Carbon core–shell nanocapsules, which without any functionalization could be used as a molecule loading material due to its high surface areas. In this system, the Au NR core had a high-absorption cross section for conversion of near-infrared light to heat, which could be explored for local hyperthermia. The carbon shell, which was biocompatible and stable even under concentrated acidic and alkaline conditions, was able to adsorb molecules with p–p interactions or electrostatic interactions. In comparison with Au NR@Si O2, Au NR@Carbon nanocapsules demonstrate the following merits:(1) simple and green synthesis method,(2) far more stable with respect to high-temperature stability and(3) larger molecule loading capacity,which indicate great potential in the biomedical applications.

Early assessment of the safety and immunogenicity of a third dose(booster)of COVID-19 immunization in Chinese adults

Inducing durable and effective immunity against severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)via vaccination is essential to combat the current pandemic of coronavirus disease 2019(COVID-19).It has been noticed that the strength of anti-COVID-19 vaccination-induced immunity fades over time,which calls for an additional vaccination regime,as known as booster immunization,to restore immunity among previously vaccinated populations.Here we report a pilot open-label trial of a third dose of BBIBP-CorV,an inactivated SARS-CoV-2 vaccine(Vero cell),on 136 participants aged between 18 to 63 years.Safety and immunogenicity in terms of neutralizing antibody titers and cytokine/chemokine responses were analyzed as the main endpoint until day 28.While systemic reactogenicity was either absent or mild,SARS-CoV-2-specific neutralizing antibody titers rapidly arose in all participants within 4 weeks,surpassing the peak antibody titers elicited by the initial two-dose immunization regime.Broad increases of cellular immunity-associated cytokines and chemokines were also detected in the majority of participants after the third vaccination.Furthermore,in an exploratory study,a newly developed recombinant protein vaccine,NVSI-06-08(CHO Cells),was found to be safe and even more effective than BBIBP-CorV in eliciting humoral immune responses in BBIBP-CorV-primed individuals.Together,these results indicate that a third immunization schedule with either homologous or heterologous vaccine showed favorable safety profiles and restored potent SARS-CoV-2-specific immunity,providing support for further trials of booster vaccination in larger populations.

Cobalt diselenide (001) surface with short-range Co-Co interaction triggering high-performance electrocatalytic oxygen evolution

Oxygen evolution reaction (OER) still suffers from the bottleneck in electrocatalytic water splitting. Herein, in virtue of volcano plots drawn by theoretical calculation, the (001) facet was screened as the superb facet of orthorhombic CoSe_(2) for OER. Afterwards, CoSe_(2)(001) nanosheets were synthesized and the exposure ratio of (001) facet is controllable with thermodynamics methods effectively. The single-facet CoSe2(001) delivered an overpotential as low as 240 mV at 10 mA·cm^(−2) in 1 M KOH, which outperformed the bulk (380 mV) as well as other CoSe_(2)-base OER catalysts reported before. Especially, a shorter Co-Co path was observed in CoSe_(2)(001) by X-ray absorption spectroscopy. Further density functional theory (DFT) studies revealed that the reversible compression on the shorter Co-Co path could regulate the electronic structure of active sites during the OER process, and thus the energy barrier of the rate-determining step was reduced by 0.15 eV. This work could inspire more insights on the modification of electronic structure for OER electrocatalysts.

Enhanced catalytic activity of Ru through N modification toward alkaline hydrogen electrocatalysis

Exploring highly efficient electrocatalysts and understanding the reaction mechanisms for hydrogen electrocatalysis,including hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) in alkaline media are conducive to the conversion of hydrogen energy.Herein,we reported a new strategy to boost the HER/HOR performances of ruthenium (Ru) nanoparticles through nitrogen (N) modification.The obtained N-Ru/C exhibit remarkable catalytic performance,with normalized HOR exchange current density and mass activity of 0.56 m A/cm^(2)and 0.54 m A/μg,respectively,about 4 and 4.5 times higher than those of Ru/C,and even twofold enhancement compared to commercial Pt/C.Moreover,at the overpotential of 50 m V,the normalized HER current density of N-Ru/C is 5.5 times higher than that of Ru/C.Experimental and density functional theory (DFT) results verify the electronic regulation of Ru after N incorporation,resulting in the optimized hydrogen adsorption Gibbs free energy (ΔG_(H*)) and hence enhancing the HOR/HER performance.

New FeNiCrMo(P, C, B) high-entropy bulk metallic glasses with unusual thermal stability and corrosion resistance

New Fe(20–35) Ni(20) Cr(20–30) Mo(5–15)(P(0.6) C(0.2) B(0.2))(20) bulk metallic glasses with excellent thermal stability,strength, and corrosion resistance have been developed through the high-entropy alloy design strategy.The high-entropy bulk metallic glasses(HE-BMGs) possess larger supercooled liquid regions of ~69 K,higher crystallization onset temperatures of ~852 K, larger undercoolings of ~109 K, and more sluggish crystallization process upon heating than the conventional metallic glass benefited from the high mixing entropy effect. The HE-BMGs also exhibit ultrahigh strength of ~3.4 GPa, Vickers hardness of ~1107,and superior corrosion resistance in acids and Na Cl solutions by formation of highly stable Cr-and Moenriched passive films. The new metal-metalloid HE-BMG system and exceptional properties give the alloys good promise for both scientific and engineering applications.

DNA methylation signature predicts cancer response to demethylation agents from profiling diverse cancer cell lines

Dear Editor,Abnormal DNA methylation,a process whereby tumor suppressors tend to be hypermethylated and silenced,is a hallmark of cancer cells[1].Removing the methylation by demethylation agents such as azacitidine and decitabine is one of the strategies to treat cancers and has been successfully used to treat certain hematological and solid tumors[2].However,there are no established DNA methylation markers or signatures that can accurately predict patients’response to treatment[2];thus,the identification of reliable predictive biomarkers for effective therapy remains a critical need in clinical practice.

High-Performance Ru_(2)P Anodic Catalyst for Alkaline Polymer Electrolyte Fuel Cells

Exploring efficient and economical electrocatalysts and understanding the mechanism for alkaline hydrogen oxidation reaction(HOR)are crucial to facilitate the development of alkaline polymer electrolyte fuel cells(APEFCs).Herein,Ru_(2)P was synthesized and used as an anodic HOR electrocatalyst for APEFC,achieving a peak power density of 1.3 W cm^(−2),the highest value among Pt-free anode electrocatalysts reported under the same conditions.Fromthe density functional theory(DFT)calculations and experimental results,it was found that besides the optimized hydrogen binding energy,the enhanced adsorption strength of oxygenated species(OH*)and the reduced work function of Ru_(2)P contributed to the enhanced HOR performance.The normalized exchange current densities of Ru_(2)P/C were 0.37 mA cm_(ECSA)^(−2) and 0.27 mAμgRu^(−1),respectively,both approximately three times higher than those of Ru when conducted in the rotating disk electrode(RDE)system.Our work provides a new pathway for exploring highly active Pt-free HOR electrocatalysts and expanding the family of anodic electrocatalysts for APEFCs.

A Rational Design of Heterojunction Photocatalyst Cd S Interfacing with One Cycle of ALD Oxide

Photo-corrosion is one of the major obstacles for CdS application in wet chemical fields, and atomic layer deposition （ALD） has been proposed as an effective way to suppress the corrosion. Here, prior to ALD coating, CdS, one facilely corrosive photocatalyst, was synthesized via hydrothermal synthesis to access the fundamental corrosion mechanism and the according corrosive sites. X-ray photoelectron spectros- copy （XPS） and X-ray diffraction （XRD） demonstrated that the failure of catalytic decomposition of methylene blue originated from the formation of soluble CdSO4 by oxidizing S2 of as-prepared CdS. High resolu- tion transmission electron microscopy （HRTEM） further identified the active sites in the V-shaped regions ofCdS nanoparticles, confirmed by the simulated electric field distribution. To rationally coat oxides on CdS, the right candidates and their thicknesses have been considered by our tunneling model with trans- fer matrix method based on quantum mechanism, upon which the thickness of protective layer should be less than 0.5 nm to maintain a high tunneling probability, and thus one cycle of ALD TiO2 or AbO3 was proposed to passivate the CdS powder to balance the carrier transportation and corrosion suppres- sion. Based on HRTEM results, we found that the active V-shaped region was covered by ALD oxides （TiO2 or AbO3）. For each case, no soluble CdSO4 has been found before and after photocatalytic reactions based XPS measurements. Importantly, we noticed that with the passivation of one cycle of ALD, the catalyst＇s lifetime was elongated up to 〉14 times higher than that of the as-prepared CdS.