ZEITSCHRIFT FUR NATURFORSCHUNG SECTION A-A JOURNAL OF PHYSICAL SCIENCES
·
2022
·Vol. 77
·期 7
·715-722
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IF 1.712
Jinghao Zhuang,Wenlin Feng,Bo Zhou,Qili Zhang,Chong Liu,Yao Gong
A series of CaSr(WO 4 ) 2 : Eu 3+ and CaSr(WO 4 ) 2 : Eu 3+ , Li + phosphors with different Eu 3+ or Eu 3+ /Li + molar contents were successfully synthesized by high-temperature solid-state reaction. Through a series of characterization methods, the composition, structure and luminescence characteristics of the sample are obtained. Upon excitation at 393 nm, the strong red light corresponding to the 5 D 0 → 7 F 2 transition of Eu 3+ can be observed. The effect of Li + charge compensation on the photoluminescence of the sample is studied. The strongest red emission is obtained through 1% Eu 3+ and 1% Li + doping. All of the results indicate that Li + charge compensation can effectively enhance the red emissions intensity of Eu 3+ -doped CaSr(WO 4 ) 2 phosphors.
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BIOCHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 3.475
Yu Zhang,Xiaohui Di,Wen Wang,Miaojia Song,Qiang Yu,Zhongming Wang,Zhenhong Yuan,Xiaoyan Chen,Huijuan Xu,Ying Guo
Methyl-2-furoate (MF) is a high-value compound, and can be produced via esterification of furoic acid derived from biobased furfural. Herein, CAL-B and [bmim][PF 6 ] were the most efficient lipase and organic medium for MF production, respectively. Based on mass action law and reaction reversibility, a mathematical model was developed. Data analysis showed the newly proposed binary regression was apparently more suitable compared to the commonly used unitary regression. The enzymatic promotion factor m i for esterification and hydrolysis was 1.8159 and 0, while the alcohol inhibition factor n i was 0 and 0.06436, respectively. Both the activation energy E a, i for esterification and hydrolysis was 84 kJ/mol, and the pre-exponential factor A i was 7.1408×10 13 and 7.8962×10 13 , respectively. Kinetics study demonstrated that CAL-B held significantly more dominant esterification activity compared to hydrolysis activity, whereas alcohol just inhibited hydrolysis activity instead of esterification activity, and the relationship between esterification/hydrolysis rate constants k i and temperature agreed with Arrhenius equation. The maximum MF yield was 82.5 % at 24 h, and the yield decreased to 75.4 % after 1 re-use of CAL-B, but maintained about 20 % for next 4 cycles. Totally, the developed model and binary regression analysis method is ideal for in-depth examination of lipase-catalyzed kinetics in heterogeneous system.
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JOURNAL OF ORGANIC CHEMISTRY
·
2023
·
IF 3.6
Qi Dang,Jiani Chen,Tianbao Li,Long Liu,Tianzeng Huang,Chunya Li,Tieqiao Chen
A palladium-catalyzed decarbonylative annulation of 2-arylbenzoic acids with internal alkynes via C(sp2)–H activation has been developed. A series of phenanthrenes were produced in moderate to good yield with good functional group tolerance. The mechanism study indicated that the C(sp2)–H activation should be the rate-determining step during the reaction.
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NEUROTOXICOLOGY AND TERATOLOGY
·
2025
·
IF 2.8
Fangfei Li,Jie Zhang,Xiaoli Ma,Hao Chen,Guiqiang Liang,Yunfeng Zou
Excessive accumulation of manganese (Mn) can cause neuroinflammation, impairing cognitive function. SPON1, a secreted glycoprotein in the extracellular matrix, is implicated in neuroinflammation, but its role in activating pro-inflammatory pathways in Mn-induced neuroinflammation remains unclear. This study employed in vivo and in vitro models to investigate Mn neuroinflammation. The expression levels of SPON1 and the ERK1/2/NF-κB pathway associated with inflammation were measured in male C57BL/6 mice after gavage of Mn at different doses (0, 25, 50, 100 mg/kg) for 12 weeks. SPON1 levels were measured after primary hippocampal neurons, primary cortical neurons, neuroblastoma cells (N2a), and microglial cells (BV2) were exposed to various concentrations of Mn for 24 h. We observed that in vivo Mn exposure significantly decreased SPON1 expression in the cortex but not in the hippocampus. Similarly, in vitro experiments demonstrated that Mn exposure significantly reduced SPON1 levels in primary cortical neurons, N2a, and BV2. In addition, Mn exposure increased the expression levels of ERK1/2 and NF-κB pathway proteins in the mouse cortex. Because BV2 cells are susceptible to inflammatory signals, they were chosen to elucidate how SPON1 induces neuroinflammation during Mn exposure. SPON1 knockdown increases the expression of inflammatory factors, whereas SPON1 overexpression inhibits the activation of the ERK1/2/NF-κB pathway and reduces inflammatory factor levels. In summary, these results suggest that Mn may affect the activation of ERK1/2/NF-κB pathway and the expression of inflammatory factors by inhibiting SPON1, ultimately promoting neuroinflammation.
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RESEARCH ON CHEMICAL INTERMEDIATES
·
2017
·Vol. 43
·期 8
·4353-4368
·
IF 1.369
Yuan Hong,He Jie,Li Ruilan,Ma Xiaoqin
The solid acid catalysts SO 4
2− /TiO 2 were prepared by the impregnation technique under two preparation conditions which were different in calcination temperature and concentration of impregnation solution of H 2 SO 4 . The characterization was carried out by using Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), temperature programmed desorption of NH 3 (NH 3 -TPD), N 2 -BET, X-ray fluorescence and thermal gravity (TG)–differential scanning calorimetry (DSC). The characteristic peaks in the FTIR spectrum were essentially the same within the calcination temperature range of 400–600 °C. The XRD results indicated that the sample could show partial specific peaks of the anatase phase as the calcination temperature was higher than 400 °C. The obvious strong acid and superacid sites of the prepared SO 4
2− /TiO 2 were conformed by the NH 3 -TPD results. The BET surface areas of 102–206 m 2 /g were measured by the N 2 -BET method, and the pore size distributions were essentially mesoporous. The TG–DSC results showed that SO 4
2− /TiO 2 would decompose at about 500 °C in the air. The solid acid SO 4
2− /TiO 2 were used for the epoxidation of castor oil. The lowest iodine value of the product was 52.65/100 g when the reaction temperature was 65 °C, reaction time was 10 h and catalyst loading was 15 wt.%.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2017
·
IF 3.359
Lang Yang,Feifei Jia,Shaoxian Song
The recovery of gold cyanide complex Au(CN) 2 − from gold cyanidation with graphene oxide (GO) and GO hydrogel have been studied to explore the possibility of the application of GO or GO hydrogel in gold cyanidation process for extracting gold. The study was performed on the adsorption of artificial Au(CN) 2 − aqueous solution on GO and GO hydrogel. The adsorption results, as well as the SEM-EDS, AFM and XPS, demonstrated that GO was a better adsorbent for the recovery of Au(CN) 2 − from aqueous solution than conventional activated carbon because of its higher adsorption capacity and adsorption rate. It has been also found that the adsorption of Au(CN) 2 − on GO followed the Langmuir isotherm and fitted well with both the pseudo-first-order and pseudo-second-order kinetics models. The recovery of Au(CN) 2 − with GO might be attributed to the interaction between Au(CN) 2 − and oxygenous function groups on GO surface. GO hydrogel exhibited excellent Au(CN) 2 − adsorption property and easy separation, which enabled it a potential adsorbent in gold cyanidation.
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JOURNAL OF MEMBRANE SCIENCE
·
2019
·
IF 7.015
Yu-Jie Shen,Li-Feng Fang,Yan Yan,Jia-Jia Yuan,Zhi-Qiang Gan,Xiu-Zhen Wei,Bao-Ku Zhu
A metal-organic composite membrane with sub-2 nm pores was developed via interfacial coordination reaction in biphasic systems for the first time. Herein, tannic acid (TA) was dissolved in water, as aqueous phase; iron(III) acetylacetonate (Fe(acac) 3 ), used as Fe(III) source, was dissolved in n -hexane as organic phase. A detailed study was conducted to obtain the defect-free TA-Fe(III) separation layer, including the salt concentration in aqueous solution, pH of the aqueous solution and the ratio of TA to Fe(acac) 3 . The results indicated that the defect-free TA-Fe(III) composite membrane formed when the tris-complex (TA 3 -Fe(III)) was achieved. The optimal condition for preparing TA-Fe(III) composite membrane was using aqueous solution containing 0.4 M NaCl at pH = 6 with the ratio of TA to Fe(acac) 3 of 10. Different from the typical separation layer formed on the membrane surface by interfacial polymerization, the TA-Fe(III) separation layer was formed in the pores of the substrate, which is attributed to the higher diffusion coefficient of Fe(acac) 3 from organic phase to aqueous phase. This work provided a novel strategy to fabricate metal-organic composite membrane with sub-2 nm pores; meanwhile, the new-prepared membrane shows a high Na 2 SO 4 rejection of 97.3% with the water permeance of 8.6 L m −2 h −1 bar −1 , and a high VB 12 rejection of 97.6%, indicating an excellent ion/molecule separation performance.
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INORGANIC CHEMISTRY
·
2024
·
IF 4.3
Han Luo,Yu Zhang,Tingyu Wang,Ling Huang,Liling Cao,Xuehua Dong,Guohong Zou
Two antimony selenites, Sb2O2SeO3 and Sb2O(SeO3)2, were synthesized by simultaneously incorporating stereochemically active lone pair electrons containing SeO32– and Sb3+. These compounds are structured with [SbOx] polyhedra and [SeO3] units within a two-dimensional framework. Both of them exhibit cutoffs at 300 and 330 nm within the ultraviolet (UV) range and demonstrate significant birefringence, with indices of 0.069 and 0.126 at 546 nm, respectively. These properties highlight their potential as UV birefringent materials. Structural analyses and theoretical calculations reveal that their exceptional birefringence results from the synergistic interactions between SeO32– anions and Sb3+ cations.
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ENZYME AND MICROBIAL TECHNOLOGY
·
2024
·
IF 3.4
Lili Zhang,Yu Hong,Jiapeng Lu,Yi Wang,Wei Luo
Transaminases (EC 2.6.1.X, TAs) are important biocatalysts in the synthesis of chiral amines, and have significant value in the field of medicine. However, TAs suffer from low enzyme activity and poor catalytic efficiency in the synthesis of chiral amines or non-natural amino acids, which hinders their industrial applications. In this study, a novel TA derived from Paracoccus pantotrophus ( pp TA) that was investigated in our previous study was employed with a semi-rational design strategy to improve its enzyme activity to 2-ketobutyrate. By using homology modeling and molecular docking, four surrounding sites in the substrate-binding S pocket were selected as potential mutational sites. Through alanine scanning and saturation mutagenesis, the optimal mutant V153A with significantly improved enzyme activity was finally obtained, which was 578 % higher than that of the wild-type pp TA (WT). Furthermore, the mutant enzyme pp TA-V153A also exhibited slightly improved temperature and pH stability compared to WT. Subsequently, the mutant was used to convert 2-ketobutyrate for the preparation of L-2-aminobutyric acid (L-ABA). The mutant can tolerate 300 mM 2-ketobutyrate with a conversion rate of 74 %, which lays a solid foundation for the preparation of chiral amines.
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ChemCatChem
·
2024
·
IF 3.8
Siyang Yan,Ruilin Feng,Jiaxu Liu,Chenxi Bai,Yanlong Qi
Graphical The dehydration of 2,4-pentanediol to unsaturated alcohol was performed over ceria-based catalysts with high selectivity. A stereocatalytic effect of CeO 2 catalyst was observed for the production of trans -3-penten-2-ol, with negligible content of cis -3-penten-2-ol. The transformation of biobased alkanediols over heterogeneous catalysts is a major object. Here, a series of catalysts were prepared for 2,4-pentanediol dehydration to 3-penten-2-ol. Ceria-based catalysts had a unique property of showing high efficiency. More importantly, a stereocatalytic effect was observed for CeO 2 , yielding trans -3-penten-2-ol with a high selectivity. Raman, XPS, TPD, and TPR were carried out to clarify the catalyst structure, and the relationship between the catalyst structure and catalytic performance were studied. The amount of Lewis acid sites can hardly be correlated with the total concentrations of the oxygen vacancies. It was suggested that the geometry structure of the active sites played a crucial role in trans -3-penten-2-ol production. The oxygen vacancies originating from CeO 2 consisted of active sites with a geometrical structure, which were different from those created by Pr doping CeO 2 . In addition, the Pr doping enhanced the oxygen migration, which resulted in side reactions, consequently, giving a lower selectivity to trans -3-penten-2-ol.
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CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Dongbo Zhang,Ning Wang,Xinyue Tang,Jiangrong Yan,Yongsheng Zhang
High-entropy oxides (HEOs) are promising materials for thermal barrier coatings (TBCs). In this study, a new type of TBC material, that is, (La 0.5 Gd 0.5 ) 2 (Ce 0.2 Nb 0.2 Yb 0.2 Ta 0.2 Zr 0.2 ) 2 O 7 [(LG)(CNYTZ)O] pyrochlore-structured HEO was designed and synthesized. The results showed that the structure of the (LG)(CNYTZ)O HEO synthesized at 1400 °C for 6 h was pure phase pyrochlore oxide. The microstructures of the (LG)(CNYTZ)O HEO solid specimens were studied after sintering at different temperatures (1500, 1520, 1540, 1550, 1560, 1580, and 1600 °C) for 6 h, respectively. The optimal sintering temperature was determined to be 1550 °C. The properties of the (LG)(CNYTZ)O HEO specimen sintered at 1550 °C for 6 h were tested. Its direct and indirect optical bandgap widths were determined to be 3.05 and 2.52 eV, respectively, from its UV–visible diffuse reflectance spectroscopy profile. Its infrared spectrum was recorded at 1100 °C, which confirmed its excellent high-temperature thermal radiation-shielding properties. Its thermal conductivity was determined in the temperature range of 30–1000 °C after correction for porosity, using the laser flash method, and was found to be in the range of 0.91–1.00 W m −1 K −1 . Its coefficient of thermal expansion ranged from approximately 7.47 × 10 −6 k −1 to 10.36 × 10 −6 k −1 in the temperature of 100–1000 °C. It also exhibited excellent thermophysical properties. Its hardness was in the range of 6.76–7.46 GPa, and its average hardness was measured to be 7.11 GPa using a microhardness tester, while its fracture toughness was in the range of 1.81–2.31 MPa m 1/2 , and its average fracture toughness was 2.06 MPa m 1/2 , respectively. These results indicate that the (LG)(CNYTZ)O HEO can be considered a suitable candidate material for TBCs.
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ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY
·
2024
·
IF 4.2
Fangfang Ding,Huimei Wang,Yingzhi Li,Xueping Leng,Jiaming Gao,Danfei Huang
Due to the massive production and use of plastic, the chronic and evolving exposure to microplastics in our daily lives is omnipresent. Nonylphenol (NP), a persistent organic pollutant, may change toxicity when it co-exists with microplastics. In this study, polystyrene microplastics (PS-MPs), either alone or with pre-absorbed NP, generated oxidative stress and inflammatory lesions to Caco-2 cells, as well as affecting proliferation via the MAPK signaling pathway and causing apoptosis. Damage to cell membrane integrity and intestinal barrier (marked by lower transepithelial electric resistance, greater bypass transport, and tight junction structural changes) leads to enhanced internalization risk of PS-MPs. Some important intestinal functions including nutrient absorption and xenobiotic protection were also harmed. It is worth noting that the exposure of PS-MPs with a diameter of 0.1 μm improved intestinal functions quickly but acted as a chemosensitizer for a long time, inhibiting cell perception of other toxic substances and making the cells more vulnerable.
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