ANALYTICA CHIMICA ACTA
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2020
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IF 5.977
Zhouxian Li,Qi Wang,Jiawei Mao,Lingyi Zhang,Weibing Zhang,Mingliang Ye
A challenge for shotgun proteomics is the identification of low abundance proteins, which is always hampered owing to the extreme complexity of protein digests and highly dynamic concentration range of proteins. To reduce the complexity of the peptide mixture, we developed a novel method to selectively enrich N-terminal proline peptides via hydrazide chemistry . This method consisted of ortho -phthalaldehyde (OPA) blocking of primary amines in peptides, reductive glutaraldehydation of N-terminal proline and solid phase hydrazide chemistry enrichment of aldehyde-modified N-terminal proline peptide. After enrichment, the number of detected peptides containing N-terminal proline increased from 1304 to 4039 and the ratio of N-terminal proline peptides jumped from 4.4% to 93.7%, showing good enrichment specificity towards N-terminal proline peptides. Besides, the ratio of identified peptides to proteins was decreased from 7.8 (29751/3811) to 1.5 (4347/2821), indicating that sample complexity was drastically reduced through this method. As a result, this novel approach for enriching N-terminal proline peptides is effective in identification of low abundance protein owing to the reduction of sample complexity.
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Journal of Spectroscopy
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2020
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IF 1.243
Liang Zhao,Chaoyu Jing,Yu Jin,Jiangping Chen,Ke Yin,Sujun Yang,Bingqing Liu,Xiao Han,Jianyu Tan
The optical constants of a liquid hydrocarbon such as liquid n-octane are basic material properties that may be used to evaluate their thermal radiation transfer capabilities. In this study, the ellipsometry method was used to measure the optical constants of liquid n-octane in the midinfrared wavelength range of 2.0–16.0 μm at temperatures of 20, 50, and 80°C. Experimental analyses indicate the significant effect of temperature on the refractive index, although it has little effect on the absorption index. With increasing temperature, the refractive index shows a linear decrease, and reduced density leads to weaker absorption intensities. The radiative properties of n-octane droplets, including the absorption and scattering efficiency factors of single droplets with droplet radii r = 10, 20, 50, and 100 μm and the absorption and scattering coefficients in a droplets-air system of droplet volume fractions fv = 2%, 3%, and 4%, were calculated using Mie theory. The numerical results indicate that, with increasing temperature, the absorption efficiency factor slightly decreases, and the variation trend of the scattering efficiency factor is more complicated. With increasing droplet radius, the absorption efficiency factor increases within the studied wavelength range, except for certain absorption peaks, but the scattering efficiency factor tends to decrease. While the absorption is greater, the scattering is weaker for a given droplet radius. With an increasing volume fraction of n-octane droplets, the absorption and scattering coefficients increase linearly within the studied wavelength range.
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CHEMICAL ENGINEERING JOURNAL
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2020
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IF 10.652
Hongjing Wang,Dandan Yang,Songliang Liu,Shuli Yin,Hongjie Yu,You Xu,Xiaonian Li,Ziqiang Wang,Liang Wang
The design of active and durable cathodic electrocatalysts with low Pt loading is critical for efficient oxygen reduction reaction. Herein, a general method is reported to prepare monodispersed Pt nanoparticle encapsulated in N-doped hollow carbon sphere with cage-bell structure (Pt@NHCS) by hard-template method. The materials with ultralow Pt content (2.8 wt%) possess typical a thin N-doped carbon layer (~12 nm) as a shell and monodispersed Pt nanoparticle (~20 nm) as a core. Due to unique structure and potential synergistic effect from interaction between Pt and nitrogen species, the cage-bell Pt@NHCS shows excellent catalytic activity and methanol-tolerant durability for oxygen reduction reaction. This method is of significant importance for the design of cost-efficiency electrocatalysts with cage-bell structure for excellent oxygen reduction reaction and beyond.
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APPLIED ENERGY
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2020
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IF 8.848
Min Xiao,Wenchao Zheng,Helei Liu,Xiao Luo,Hongxia Gao,Zhiwu Liang
Protonation and carbamate formation are critical reactions for CO 2 capture using amine-based absorbents which impact both CO 2 absorption and amine regeneration. In this regard, thermodynamic analysis towards CO 2 absorption in N -methylaminoethanol solution is carried out with specific attention to the corresponding protonation and carbamate formation reactions. The CO 2 absorption mechanism is investigated with the acquisition of reaction equilibrium constant and heat of reaction. CO 2 absorption performance of N -methylaminoethanol solution was evaluated in terms of CO 2 loading and solution pH. A thermodynamic model was then developed to mathematically describe the investigated system and make prediction on equilibrium CO 2 solubility, species profiles, and absorption/regeneration heat. Results show that the average relative deviation of equilibrium CO 2 solubility calculated from the is 4.2%. The predictive species profile and CO 2 absorption heat of N -methylaminoethanol solution indicates less energy cost to desorb CO 2 . This is in line with the relative unstable N -methylaminoethanol carbamate formation and consequential conversion to (bi)carbonate. The position of N -methylaminoethanol as a potential absorbent in amine based carbon capture is shown in terms of chemical reaction constants, equilibrium CO 2 solubility, second order rate constant ( k 2 ), and p Ka .
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ENERGY
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2020
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IF 6.082
Rujie Wang,Shanshan Liu,Qiangwei Li,Shihan Zhang,Lidong Wang,Shanlong An
Blended amine solvents are considered potential alternatives to monoethanolamine for CO 2 capture, for the fast absorption kinetics of primary/secondary amine and low regeneration penalty of tertiary amine. In this research, blended amine solvents comprising N,N-dimethylcyclohexylamine (DMCA) and N-methylcyclohexyamine (MCA) were proposed. CO 2 absorption increased the polarity of the products and ensured the absorbent remained homogenous throughout the absorption/desorption cycles. Through quantum chemical calculation, the low stability of MCA-carbamate was confirmed by a ΔΔG 3 value of −6.41 kcal/mol, and a possible reaction route from carbamate to bicarbonate was revealed. Thus, the CO 2 capacity of DMCA-MCA reached 0.875–0.985 mol CO 2 /mol amine. Moreover, MCA exhibited considerably low forward energy barrier for zwitterion formation (2.7 kcal/mol), and the CO 2 absorption of DMCA could be accelerated through the proton transfer reaction with the MCA-zwitterion. Accordingly, the total mass transfer coefficient of CO 2 in DMCA-MCA approached 2.02 × 10 −10 mol/cm 2 s Pa, which was 1.2-fold higher than that of 5 M MEA. The total regeneration energy of DMCA-MCA blend was estimated at 2.20 GJ/t CO 2 , which was 44.9% lower than 5 M MEA. This study developed a novel DMCA-MCA blended solvent with rapid absorption rate, huge CO 2 capacity and efficient regeneration for CO 2 capture.
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FOOD CHEMISTRY
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2020
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IF 6.306
Yu Lu,Cheng Li,Jie Liu,Wenqi Huang,Yuerong Yang,Yue Jia,Tingting Liu,Linjuan Huang,Zhongfu Wang
Goat milk oligosaccharides represent an unexplored multi-functional ingredient for the dairy industry. Here, we qualitatively and quantitatively compared the N/O -glycome at different lactation stages via online hydrophilic interaction chromatography-tandem mass spectrometry. Complex N -glycans and high mannose N -glycans constituted 82.1% and 17.9% of the glycan pool, respectively. N -glycans with isomers containing non-bisected antenna complex structures accounted for 30.8%. N -glycans modified with Neu5Ac, Neu5Gc and fucosylated were 3.7%, 5.3% and 35.3%. The triantennary trifucosylated complex N -glycan (H5N5F3) was reported for the first time. A comparison between colostrum and mature milk revealed a 1.20-fold decrease in total N -glycans and 1.66-fold decrease in fucosylation with ongoing lactation, echoing the trend in human milk. Similarly, Neu5Ac- and Neu5Gc-modified sialylation decreased by 1.69 and 3.62 times, respectively. In the O -glycome, 46.2% of structures were O -linked core 1, 23.1% were O -linked core 2, 7.7% were O -linked core 3 and core 4. As lactation progressed, overall O -glycans content decreased by 1.26-fold. Unlike human milk, Neu5Ac- and Neu5Gc-modified sialylation increased by 4.4 and 2 times, respectively. These findings will facilitate research on the structure-function relationship of goat milk oligosaccharides and the development of formula food targeting different age groups.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2020
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IF 4.65
Jianfei Xiao,Yuan Wang,Tian C. Zhang,Shaojun Yuan
A novel porous carbon derived from glucose and dicyandiamide incorporated with reduced graphene oxide (rGO) was prepared for CO 2 capture and supercapacitors . In this synthesis, one-pot hydrothermal and KOH activation were employed to obtain reducing graphene oxide/N-doped porous carbon (rGO/NPC) composites. Among the rGO/NPC composites derived, the sorbent rGO/NPC-600-2-1 (1 represents the addition amount of graphene oxide is 1% of the total mass of glucose and dicyandiamide, 2 represents the mass ratio of potassium hydroxide to the precursor of carbon composite material is 2 and 600 means activation temperature is 600 °C) had a large surface area of 865.1 m 2 g −1 , a rich nitrogen doping amount of 7.07 wt%, and a high CO 2 capture ability of 5.77 mmol/g at 298 K. Additionally, the as-synthesized rGO/NPC-600-2-1 was used as a supercapacitor electrode, providing a specific capacitance 210.8 F g −1 in 6 M KOH electrolyte under ambient conditions and excellent charge and discharge long cycle stability (circa 100% capacitance retention at a current density of 10 A g −1 after 10000 cycles). Even at a high current density of 20 A g −1 , a capacity of 141.1 F g -1 is still maintained. The results above suggested that the rGO/NPC composites are applicable candidates for both electrochemical energy storage and CO 2 capture.
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APPLIED SURFACE SCIENCE
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2020
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IF 6.182
Linjuan Wang,Siva Krishna Karuturi,Ling Zan
We present one-pot hydrothemal syntheis of SnS 2 -In 2 S 3 p-n heterostructures for photocatalytic reduction of Cr 6+ to Cr 3+ . The conduction bands of In 2 S 3 and SnS 2 serve as the photogenerated electron donors and acceptors, respectively, forming a p-n junction band alignment improving the photogenerated charge separation efficiency. Through a detailed investigation of photocurrent spectra, photoluminescence spectra and electrochemical impedance, the heterojunction formation is shown to enhance the photogenerated charge separation and transport properties. In addition, the analysis of 5,5-Dimethyl-1-pyrroline N-oxide (DMPO) spin trapping electron spin resonance (ESR) spectra and band structure further testify the p-n junction of the composite catalyst that could accelerate the electron transport and change the pathway of photocatalytic process toward Cr 6+ reduction. Furthermore, SnS 2 -In 2 S 3 heterojunction photocatalyst achieved 3 times and 67 times higher efficiency than pure In 2 S 3 and SnS 2 photocatalysts under visible light toward Cr 6+ reduction. Moreover, the SnS 2 -In 2 S 3 p-n heterojunction photocatalyst demonstrates Cr 6+ removal in a weak alkaline solution, breaking through the challenge of Cr 6+ reduction in an alkaline environment.
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Canadian Journal of Chemistry
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2020
·Vol. 99
·期 3
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IF 1.171
Jianfa Chen,Tianxiang Jin,Hangchun Deng,Jie Huang,Guangyuan Ren,Yong Qian
In this work, MoO2@NPGA nanocomposites were successfully prepared via a simple hydrothermal and calcination route. The as-prepared MoO2@NPGA composites exhibit a synergistic effect between MoO2 and N,P-codoped graphene aerogels, which can significantly improve the electrochemical performance of the MoO2@NPGA electrodes. Moreover, the results also proved that the mass loading of MoO2 has a huge effect on the electrochemical properties of MoO2@NPGA composites. With an appropriate amount of MoO2, the MoO2@NPGA composite shows a high specific capacitance (335 F g−1 at 1 A g−1) and excellent cycle stability (capacitance remains at 88% after 6000 cycles). Furthermore, the assembled symmetric supercapacitor displays a high energy density of 23.75 W h kg−1 at a power density of 300 W kg−1 and can maintain an energy density of 17.1 W h kg−1 when the power density reaches up to 6005 W kg−1.
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Materials Research Express
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2020
·Vol. 7
·期 9
·095501
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IF 1.929
Ruijie Jiang,Lingling Xu,Nan Wu
Nontoxic, low-cost microcapsule phase change materials (MicroPCMs) were successfully manufactured via suspension polymerization, in which n-dodecanol was employed as the core material and crosslinked polymethyl methacrylate as the wall material. Alkylphenol polyoxyethylene ether (OP-10), polysorbate-20 (Tween-20), sodium salt of styrene-maleic anhydride polymer (SMA), sodium dodecyl sulfonate (SDS), and hexadecyltrimethylammonium chloride (1631) were employed as emulsifiers to investigate the effects of the type and amount of emulsifier on MicroPCMs. In addition, the effects of different types of crosslinking agents on the fabrication of MicroPCMs were investigated. Scanning electron microscopy was used to observe the micro-morphology of MicroPCMs. The chemical structure of the MicroPCMs was detected via Fourier transform infrared spectroscopy. The thermal properties and thermal stability of the MicroPCMs were analyzed using a differential scanning calorimeter and a thermal gravimetric analyzer, respectively. Particle size distributions of the MicroPCMs were measured using a particle size analyzer. The results demonstrate that MicroPCMs with regular morphology were prepared when the mass ratio of the SMA to the oil phase was 3%, and the latent heat and yield of the MicroPCMs were 80.29 J g−1 and 84%, respectively. Furthermore, the MicroPCMs were successfully synthesized using pentaerythritol triacrylate containing the hydroxyl group as the crosslinking agent with an average particle size of 14.18 μm and excellent thermal stability.
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CHEMICAL PAPERS
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2020
·Vol. 75
·期 1
·115-122
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IF 1.68
Gao Jie,Zhang Lingfan,Qian Junchao,Chen Feng,Zhang Wenqing
N-doped TiO 2 fiber membranes were prepared by electrospinning method and adsorptive chitosan was added as a nitrogen source. The obtained TiO 2 fiber membranes were analyzed by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The results show that the film has adsorption properties; furthermore, the morphology of the TiO 2 fiber with a chitosan content of 0.5 g after calcination provides the best catalytic performance; An anatase–rutile titania was found in the oxidized fiber film found in the Raman spectrum TiO 2 ; XPS demonstrated that the introduction of chitosan could replace N atom with partial lattice oxygen in TiO 2 . Moreover, the degradation rate of methylene blue of the material was about 60–80% after 4-h reaction, and the maximum degradation rate was achieved by nanofiber film with chitosan concentration of 0.5 g.
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MICROPOROUS AND MESOPOROUS MATERIALS
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2020
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IF 4.551
Baoxun Zhao,Changsheng Song,Fei Wang,Wenwen Zi,Hongbin Du
Carbon materials are attracting increasing attention because they are widely applied in batteries, supercapacitors , catalysis and other fields. In this work, we report a simple one-pot method to produce nitrogen-doped carbon materials (NCMs) by reacting N-bromosuccinimide with calcium carbide . The obtained carbon structures are partially graphitic, with significant amount of nitrogen doped into the carbon network. The texture properties of NCMs vary with the preparative temperature. The NCM prepared at 700 °C possessed dual micropores (7 Å and 12 Å) and mesopores with the largest specific surface area of 1436 m 2 g −1 . It exhibited good charge storing performance when used in a capacitor, with a high specific capacitance of 214.8 F g −1 at the current density of 0.2 A g −1 . The capacitance remains 96% after 5000 cycles. This work provides a simple way to synthesize N-containing carbon materials with excellent charge storage properties, which may be used to synthesize other tailored carbon materials with various properties.
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