International Journal of Electrochemical Science
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2023
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IF 1.5
Huanghua Zhang,Yuming Zhao,Jinhui Liu,Jilei Xu,Dong Guo,Chenxu Li,Xianghong Zhou,Peixu Yang,Shaojun Zhang
The corrosion behavior of Mg-7Nd and Mg-10Y binary alloys were investigated through scanning electron microscope observation, hydrogen evolution, weight loss experiment and electrochemical test. It was found that the corrosion rates of two alloys are mainly influenced by the micro-galvanic corrosion between the second phase and α-Mg matrix, and the second phases (Mg 12 Nd and Mg 24 Y 5 ) have a higher activity than α-Mg matrix and act as an anode to corrode preferentially during the micro-galvanic corrosion process. Mg-7Nd alloy has a faster corrosion rate than Mg-10Y alloy due to the fact that it contains more second phase and the second phase containing Nd elements is more reactive. The different distribution of rare earth elements in the alloy can lead to different corrosion morphology.
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ACS Catalysis
·
2018
·
IF 11.384
Cheng Liang,Qiyi Ma,Haoran Yuan,Yongtao Wang,Jianyong Mao,Zhirong Chen,Jia Yao,Haoran Li
An investigation of aerobic oxidation of 2-methoxy-4-methylphenol to vanillin catalyzed by a number of cobalt salts, complexes, oxides, and hydroxides in alkaline solutions is reported. A good yield of vanillin (90%) was obtained when CoCl2 was used as the catalyst, while a poor yield (6%) was obtained with Co3O4. Unexpectedly, however, the Co3O4 catalytic activity was restored after heating in an alcoholic solution of NaOH for 24 h, producing a good yield of vanillin (85%). The recovered catalytic activity of Co3O4 indicated a conversion of inactivated heterogeneous particles to activated particles. In addition, precipitates were generated when “homogeneous” CoCl2 was employed as a catalyst, making us wonder about the true nature of the catalyst in this reaction. A series of experiments are described, including kinetic studies, filtration tests, centrifugation tests, dynamic light scattering, transmission electron microscopy, X-ray photoelectron spectroscopy, and powder X-ray diffraction, for the investigation of the true catalyst under catalytic conditions. The key observations led to the conclusion that the cobalt salts and complexes act as precatalysts that transform to cobalt oxide/hydroxide [CoOx(OH)y] nanoparticles, which is responsible for the benzylic C(sp3)–H oxyfunctionalization of 2-methoxy-4-methylphenol. Additionally, the size of the particles is decisive for catalyst performance. The nature of the active nanoparticles was also studied. With regard to the identification of homogeneous or heterogeneous catalysis, this study provides a complement to existing catalytic reaction types.
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Polymer Chemistry
·
2018
·Vol. 9
·期 20
·2830-2842
·
IF 4.927
Mo Zhu,Nairong Hao,Jinxian Yang,Lianwei Li
V-type (B∼∼A∼∼B) and Y-type (A∼∼∼∼B2) macromonomer approaches are two of the most widely adopted synthetic methodologies for the preparation of long-subchain hyperbranched polymers (LHPs) with a controlled subchain length. However, little attention has been paid to the difference of the structural regularity of hyperbranched polymers prepared via the two approaches in previous related studies. This work aims to elucidate how these two synthetic approaches quantitatively influence the polymerization, branching pattern and solution properties of the prepared hyperbranched polymers. First, two sets of model hyperbranched polystyrenes (HPSV and HPSY) were prepared from V-type and Y-type macromonomers by a combination of atom transfer radical polymerization (ATRP) and azide–alkyne cycloaddition coupling reaction, respectively. The intrachain cyclization study indicated that the macromonomer self-cyclization during the interchain coupling process was strongly affected by the chain length and the structure of the used macromonomer as well as the reaction concentration. The V-type macromonomer was found to be less inclined to undergo interchain coupling due to the stronger steric hindrance effect. Furthermore, via triple-detection size exclusion chromatography (TD-SEC) characterization, the intrinsic viscosity ([η]) and the radius of gyration (Rg) were found to be scaled to the molar mass of the macromonomer (Mm) and the molar mass of the entire chain (Mt) as [η] = KηMtνMmμ (μ ≃ 0.25 and ν ≃ 0.40) and Rg = HRMtαMmβ (α ≃ 0.47 and β ≃ 0.083) for both HPSV and HPSY samples. These scaling relationships evidenced that both HPSV and HPSY hyperbranched structures hold a similar statistically fractal feature. More importantly, the determined values of ratios Kη,Y/Kη,V (∼1.5) and HR,Y/HR,V (∼1.2) demonstrated, for the first time, that the average equivalent length of the branching subchain (Ls) for HPSY is much longer than the initial macromonomer chain length (Lm), i.e. Ls = 2.5Lm while Ls is exactly equal to 1/2Lm for HPSV. This finding clearly clarified the difference between Ls and Lm, and thus the terms of Ls and Lm should not be misused in the future structure–property study. Finally, the value of the Rg/Rη ratio is determined to be ∼1.05 and ∼1.15 for HPSV and HPSY samples (Rη: viscometric radius), respectively, which are much smaller than the typical values for linear chains in good solvents (1.20–1.40), revealing the less draining nature of these hyperbranched structures.
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Nanomaterials
·
2017
·Vol. 7
·期 12
·448
·
IF 3.553
Dandan Ju,Feng Song,Yingdong Han,Wenjing Cui,Aihua Zhou,Shujing Liu,Xueqin Wang,Ming Feng,Chengguo Ming
We synthesized the uniform core-shell microstructured compounds with hexagonal phase NaYF4:Er/Yb microrods as the core and hexagonal phase NaLnF4(NaYbF4, NaLuF4:Yb/Tm, NaYF4:Yb/Er, NaYF4:Eu) as the shell based on the hydrothermal reaction. These microscale core-shell structures provided a platform for the spatially confining optical process while possessing high luminescence efficiency. The thickness of the shell could be controlled by adjusting the amounts of shell precursor, which significantly affected the intensity of the shell dopant ions emission and the emission color of core-shell upconversion luminescence (UCL). The uniform NaYF4@NaLnF4(Ln = Y, Lu, Yb) microrods, with a series of rare-earth ions doped into the core and shell layer at various doping concentrations, achieved color-tuning of the upconversion (UC) emission and dual-mode emission at the single-microcrystal level, thus allowing the efficient utilization of core-shell microcrystals in the photonics and security labeling. This study suggests a new class of luminescent materials in the microscopic field.Keywords:NaYF4microcrystals;microscale core-shell structures;multicolor tuning;dual-mode emission
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ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Jing Liu,Bo Zheng,Pei Wang,Xingang Wang,Bin Zhang,Qiuping Shi,Tingfei Xi,Ming Chen,Shaokang Guan
Bioabsorbable magnesium alloys are becoming prominent as temporary functional implants, as they avoid the risks generated by permanent metallic implants such as persistent inflammation and late restenosis. Nevertheless, the overfast corrosion of Mg alloys under physiological conditions hinders their wider application as medical implant materials. Here we investigate a simple one-step process to introduce a cross-linked 3-amino-propyltrimethoxysilane (APTES) silane physical barrier layer on the surface of Mg–Zn–Y–Nd alloys prior to electrostatic spraying with rapamycin-eluting poly(lactic-co-glycolic acid) (PLGA) layer. Surface microstructure was characterized by scanning electron microscope and Fourier transform infrared spectroscopy. Nanoscratch test verified the superior adhesion strength of PLGA coating in the group pretreated with APTES. Electrochemical tests combined with long-term immersion results suggested that the preferable in vitro anticorrosion behavior could be achieved by dense APTES barrier. Cell morphology and proliferation data demonstrated that APTES pretreated group resulted in remarkably preferable compatibility for both human umbilical vein endothelial cells and vascular smooth muscle cells. On the basis of excellent in vitro mechenical property, the animal study on the APTES pretreated Mg–Zn–Y–Nd stent implanted into porcine coronary arteries confirmed benign tissue compatibility as well as re-endothelialization without thrombogenesis or in-stent restenosis at six-month followup.
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Metals
·
2025
·Vol. 15
·期 3
·307
·
IF 2.5
Ziyang Ruan,Zifan Zhao,Jing Feng
Rare-earth tantalates (RETaO4) are considered as a type of emerging thermal barrier coating materials applied to the hot components of gas turbines and aerospace engines due to their excellent thermal stability, high-temperature fracture toughness, corrosion resistance and extremely low thermal conductivity. However, the relatively low hardness and thermal expansion coefficients may limit their service lifetime in a harsh engine environment. To address the current limitation of rare-earth tantalates and further optimize the mechanical and thermal properties, the defective fluorite-structured Y₂Zr₂O₇ (YZ) was introduced as a second phase into the YTaO4(YT) matrix to form YT1−x–YZx(x = 0, 0.25, 0.5, 0.75, 1) composite ceramics in this work. The mechanical and thermal properties of YT1−x–YZxcomposite ceramics are significantly improved compared to pure-phase YTaO4ceramics. The Vickers hardness of YT1−x–YZx(x = 0.25, 0.5, 0.75) composite ceramics is 9.1~11.3 GPa, which are 2~2.5 times higher than that of YTaO4(4.5 GPa). Among them, YT0.75–YZ0.25exhibits a maximum fracture toughness (3.7 ± 0.5 MPa·m1/2), achieving a 23% improvement compared to YTaO4(3.0 ± 0.23 MPa·m1/2) and a 118% improvement compared to Y2Zr2O7(1.73 ± 0.28 MPa·m1/2). The enhancement is attributed to the combined effect of the intrinsic strengthening of the second phase, as well as the residual stress and grain refinement caused by the introduction of a second phase. Additionally, the thermal expansion coefficients of YT1−x–YZxcomposite ceramics at 1673 K range from 10.3 × 10⁻⁶ K⁻1to 11.0 × 10⁻⁶ K⁻1, which is also higher than that of YTaO4(10.0 × 10−6K−1). Consequently, the superior mechanical and thermal properties indicate that YT–YZ composite ceramics possess promising application prospects for thermal barrier coatings.
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BIOSENSORS & BIOELECTRONICS
·
2021
·
IF 10.618
Min Chen,Zhen Song,Rui Han,Yang Li,Xiliang Luo
The nonspecific adsorption and accumulation of biomolecules on electrode interfaces remains a challenge for sensitive and accurate detection of disease markers in complex biological media, and it is highly desired to develop antifouling biosensors capable of assaying targets in complicated real liquids. Herein, an efficient and simple antifouling biosensor was constructed based on a self-designed Y-shaped peptide. The Y-shaped peptide was designed with two branches: one branch with the peptide sequence of EKEKEKE for antifouling, and the other branch with the peptide sequence of HWRGWVA for recognizing of human IgG. Under optimized experimental conditions, electrodes modified with Y-shaped peptides exhibited excellent antifouling and electrochemical sensing performances. The developed biosensor was able to effectively resist biofouling in various protein solutions and even serum samples, and the linear range of the biosensor for human IgG detection was from 100 pg mL −1 to 10 μg mL −1 , with a relatively low limit of detection of 32 pg mL −1 (S/N = 3). The antifouling biosensor possesses the capability of assaying human IgG in real serum samples, and this strategy of developing low fouling biosensors based on Y-shaped peptides can be readily expanded to the construction of other biosensing systems for different targets.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2016
·
IF 4.758
Bingying Jiang,Fangzhen Li,Cuiyun Yang,Jiaqing Xie,Yun Xiang,Ruo Yuan
The construction of simple and highly sensitive aptasensors will significantly advance the monitoring of proteins. In this work, we have developed a convenient and label-free protein-induced catalytic hairpin assembly signal amplification approach for aptamer-based sensitive electrochemical detection of thrombin in human serums. The target thrombin binds the aptamer-containing hairpin probes immobilized on the sensor electrodes and triggers catalytic assembly of other two hairpins to form many G-quadruplex Y-junction DNA structures in situ . These G-quadruplex structures further associate with hemin to form G-quadruplex/hemin complexes, which are then subject to electrochemical measurement and generate substantially amplified current output for label-free and sensitive detection of thrombin. The developed aptasensor shows a dynamic range of 0.01–1.0 nM and a detection limit of 6.0 p.m for thrombin detection. The sensor can also discriminate the target thrombin against other non-target proteins and exhibits promising results for detecting thrombin in human serums. With the successful construction of the thrombin aptasensor, our signal amplified method can be potentially applied to detect other target molecules by choosing appropriate aptamer/ligand pairs.
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CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Wenwu Zhou,Yasong Zhou,Qiang Wei,Sijia Ding,Shujiao Jiang,Qing Zhang,Meifang Liu
Mesoporous Y composites which exhibit both crystallized micropores and large mesopores with narrow mesopore diameter distributions and controlled pore diameters were successfully synthesized. The composite is synthesized through an elaborate design of the SiO 2 @cationic surfactant cetyltrimethylammonium bromide (SiO 2 @CTAB) micelle swelled by an appropriate amount of 1,3,5-trimenthylbenzene (TMB); it is subsequently fabricated from the condensing of the Y zeolite precursors, which contain Y zeolite seeds, on the mesoscale micelle followed by a hydrothermal crystallization process. The effect of synthesis conditions such as the amounts of CTAB, TMB and TEOS added to the synthesis system on the physicochemical properties of the obtained products was examined. The as-synthesized materials were carefully characterized by employing XRD, N 2 adsorption–desorption, SEM, TEM and pyridine-adsorbed FTIR techniques. The mesoporous Y zeolite exhibited both the typical diffraction characteristics of Y zeolites in the wide-angle XRD pattern, and the typical diffraction characteristics of a narrowly dispersed mesopore structure in the small-angle XRD pattern is successfully synthesized for the first time. Finally, the adsorption capacity for DBT and 4,6-DMDBT by samples with different mesopore diameters were assessed by a batch method. Sample MY-0.5C-0.35T-0.9B showed the highest capacity for adsorbing DBT in model diesel, and sample MY-0.5C-0.35T-1.5B showed the highest capacity for adsorbing 4,6-DMDBT in model diesel. Most importantly, sample MY-0.5C-0.35T-1.5B showed the highest adsorptive rate for both DBT and 4,6-DMDBT, which is at least 10 times faster than that of sample MY-0C-0.35T-0B because of the elimination of the diffusion limitation.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2016
·
IF 2.653
Huan Wu,Yanmei Zhao,Xuanping Tan,Xiaoqing Zeng,Yuan Guo,Jidong Yang
A convenient fluorescence quenching method for determination of Quizalofop-p-ethyl(Qpe) was proposed in this paper. Eosin Y(EY) is a red dye with strong green fluorescence (λex/λem = 519/540 nm). The interaction between EY, Pd(II) and Qpe was investigated by fluorescence spectroscopy, resonance Rayleigh scattering(RRS) and UV–Vis absorption. Based on changes in spectrum, Pd(II) associated with Qpe giving a positively charged chelate firstly, then reacted with EY through electrostatic and hydrophobic interaction formed ternary chelate could be demonstrated. Under optimum conditions, the fluorescence intensity of EY could be quenched by Qpe in the presence of Pd(II) and the RRS intensity had a remarkable enhancement, which was directly proportional to the Qpe concentration within a certain concentration range, respectively. Based on the fluorescence quenching of EY-Pd(II) system by Qpe, a novel, convenient and specific method for Qpe determination was developed. To our knowledge, this is the first fluorescence method for determination of Qpe was reported. The detection limit for Qpe was 20.3 ng/mL and the quantitative determination range was 0.04–1.0 μg/mL. The method was highly sensitive and had larger detection range compared to other methods. The influence of coexisting substances was investigated with good anti -interference ability. The new analytical method has been applied to determine of Qpe in real samples with satisfactory results.
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BMC PLANT BIOLOGY
·
2025
·Vol. 25
·期 1
·1613
·
IF 4.8
Ghanaim Amira M.,Mahmoud Ghada A.,Mohamed Heba I.,Hanafy Rania S.,Zaki Laila M.,Mahmoud Mohamed,Mogazy Asmaa M.
Background Plant viral infections threaten global food security and cause major crop losses. This study investigates the antiviral effects of biosynthesized Chitosan nanoparticles (ChNPs) with Bacillus subtilis 1211 EMCCN against potato virus Y (PVY) and their influence on tomato growth and yield. Results Scanning electron microscopy showed clusters of crystals on ChNPs, while transmission electron microscopy revealed that the nanoparticles were spherical, ranging from 12 to 198 nm. Energy-dispersive X-ray spectroscopy confirmed the presence of carbon, oxygen, sodium, and phosphorus, and Fourier-transform infrared analysis identified typical chitosan functional groups, including hydroxyl, carbonyl, and amine. Tomato leaves were treated with ChNPs, B. subtilis , or both to evaluate their effectiveness against PVY. The treated plants exhibited a marked reduction in both disease severity and PVY concentration compared to the untreated controls. By 28 days post-inoculation, infectivity decreased to 46.7% in plants treated with Bacillus subtilis, 33.3% with ChNPs, and reached the lowest level of 20% in the combined treatment. The combined priming strategy significantly enhanced plant growth attributes, with increases in shoot length (95.0%), root length (47.0%), leaf area (668.1%), plant height (30.7%), shoot and root fresh weight (370.0% and 162.9%), and shoot and root dry weight (562.7% and 127.7%). Biochemical and physiological analyses revealed substantial increases in total pigments (268.4%), flavonoids (112.2%), phenols (59.4%), α-tocopherol (92.1%), ascorbic acid (30.1%), anthocyanins (71.3%), peroxidase (51.9%), catalase (39.6%), polyphenol oxidase (73.6%), amino acids (119.9%), proline (93.3%), soluble sugars (128.0%), and proteins (614.0%) in shoots. Yield components, including carotenoids and anthocyanins, were also significantly enhanced. Importantly, oxidative stress indicators were markedly reduced, with malondialdehyde and hydrogen peroxide levels decreasing by 76.8% and 72.6%, respectively, in treated plants compared to infected plants. Conclusion These findings suggest that combination between ChNPs and B. subtilis offers an eco-friendly method to enhance tomato yield and effectively manage viral diseases by activating the plants' defense mechanisms.
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CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Wei Wan,Xinxin Han,Yayun Zhou,Fangrui Chen,Xiping Jing,Shi Ye
Developing a secure and unclonable anti-counterfeiting technology with more dimensional encryptions is urgently demanded. All-inorganic halide perovskites hold great potential for applications in advanced fluorescence anti-counterfeiting owing to their superior optical properties, such as tunable emission colors, narrow emission peaks, etc. By further utilizing the feasibility of anion exchange for perovskite halides, this research successfully designs five-dimensional (5D) anti-counterfeiting barcodes with core–shell-like structured perovskite-like oxide and perovskite halide composites. The composites are prepared by a facile synthesis method, which includes adhesive growth of Cs(Pb x Mn 1-x )(Cl y Br 1-y ) 3 on the surface of CsCa 2 Ta 3 O 10 : Yb, Er (abbreviated as CCTO: Yb, Er@CsMX 3 ) via sharing Cs + at the interface. The unique structure makes it possess sensitivity to some additive decrypted inks, offering one more intriguing anti-counterfeiting dimension beyond the common dual-mode fluorescence and time-gating technique. The CCTO: Yb, Er@CsMX 3 composites exhibit typical green upconversion (UC) luminescence under a 980 nm laser, red or green or blue (RGB) emission under ultraviolet (UV) light irradiation, ns-ms emission decay time, and changeable emission color when treated with decrypted inks. The fluorescent inks and barcodes are simple for fabrication, efficient for coding, easy for viewing and difficult for cloning, making them promising for anti-counterfeiting applications.
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