JOURNAL OF ORGANIC CHEMISTRY
·
2019
·
IF 4.745
Fei-Fei Chen,Yu-Hui Zhang,Zhi-Jun Zhang,Lei Liu,Jian-Ping Wu,Jian-He Xu,Gao-Wei Zheng
(R)-Amination mediated by (R)-specific ω-transaminases generally requires costly d-alanine in excess to obtain the desired chiral amines in high yield. Herein, a one-pot, trienzymatic cascade comprising an (R)-specific ω-transaminase, an amine dehydrogenase, and a formate dehydrogenase was developed for the economical and eco-friendly synthesis of (R)-chiral amines. Using inexpensive ammonium formate as the sole sacrificial agent, the established cascade system enabled efficient ω-transaminase-mediated (R)-amination of various ketones, with high conversions and excellent ee (>99%); water and CO2 were the only waste products.
研究领域:
生物催化
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有机合成
·
酶工程
·
手性化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYST
·
2019
·Vol. 144
·期 12
·3892-3897
·
IF 4.019
Xiaobin Wang,Zhishan Fang,Zhuoyi Li,Wen Ying,Danke Chen,Haiping He,Xinsheng Peng
Mercury, as one of the most prevalent toxic metals released by various natural and anthropogenic processes, causes severe pollution of soil and groundwater. In this work, R-phycoerythrin (R-PE) proteins encapsulated into ZIF-8 composite thin films were prepared via a solid-confinement conversion process and applied as fluorescent sensors for mercury ion detection. The R-PE proteins encapsulated into ZIF-8 exhibit dual color emissions including green (518 nm) and red (602, 650 nm) fluorescence, while the original orange emission (578 nm) of pure R-PE is significantly suppressed. R-PE@ZIF-8 presents excellent selectivity and sensitivity for mercury detection in a large pH range without buffer solution. Under the optimal conditions, there is a good linear relationship between the fluorescence quenching efficiencies of R-PE@ZIF-8 and logarithmic concentrations of mercury ions in the range of 0.001–50 μM with the detection limit (LOD) of 6.7 nM much lower than the guideline value given by the World Health Organization. Furthermore, multi-peak detection of R-PE@ZIF-8 improves the detection accuracy of Hg2+ concentration.
研究领域:
环境科学
·
生物化学
✓ 已验证
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2016
·
IF 3.138
Ping Shao,Huiling Ma,Qiang Qiu,Weiping Jing
The physical stability of R-(+)-Limonene emulsions stabilized by Ulva fasciata polysaccharide (UFP) was investigated in this study. Emulsion physical stability was evaluated under different polysaccharide concentrations (1%–5%, wt/wt) and pH values (3.0–11.0). The stability of R-(+)-Limonene emulsions was demonstrated by droplet size distribution, rheological properties, zeta potential and visual phase separation. R-(+)-Limonene emulsions displayed monomodal droplet size distributions, high absolute values of zeta potential and good storage stability when 3% (wt/wt) UFP was used. The rheological properties and stability of R-(+)-Limonene emulsions appeared to be dependent on polysaccharide concentration. The emulsion stability was impacted by pH. Higher zeta potential (−52.6 mV) and smaller mean droplet diameter (2.45 μm) were achieved in neutral liquid environment (pH 7.0). Extreme acidity caused the flocculation of emulsions, which was manifested as phase separation, while emulsions were quite stable in an alkaline environment. Through comparing the stabilities of emulsions stabilized by different emulsifiers (i.e. UFP, GA and Gelatin), the result suggested that UFP was the best emulsifying agent among them.
研究领域:
食品科学
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生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Qiubo Lan,Jinxu Ma,Siyuan Li,Kepi Chen,Cuiwei Li,Linan An
Since high-entropy oxide has a huge compositional space, it is urgent to develop efficient methods to quickly find the compositions that can form single-phase materials. In this paper, taking (Ce, Zr, Hf, Yb, Nb)O 2 system as an example, we carried out the design and preparation of high-entropy fluorite oxides (HEFOs) by constructing a R ‾ -S diagram. Three single-phase HEFOs have been successfully design and synthesized. The impedance measurement showed that the three materials are electronic conductors, which exhibited relatively low thermal conductivities ranging between 1.6 W/m·K ∼1.9 W/m·K. The current study suggests that R ‾ -S diagram is a useful tool for quickly selecting compositions that can form single-phase high-entropy oxides.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
BIOCATALYSIS AND BIOTRANSFORMATION
·
2018
·
IF 1.06
Ou Zhimin,Lan Ma,Yangpin Niu,Jian Cui
(R)-(-)-mandelic acid was synthesized by two-step biotransformation. (R)-(-)-mandelic acid ethyl ester was obtained via asymmetric reduction of ethyl benzoylformate by Saccharomyces cerevisiae CGMCC No. 3361 at the first step. The conversion and enantiomeric excess of R-(-)-mandelic acid ethyl ester reached 99.8% and 100%, respectively. (R)-(-)-mandelic acid was obtained via hydrolysis of (R)-(-)-mandelic acid ethyl ester by Bacillus cereus CGMCC No. 12336 at the second step. The conversion and enantiomeric excess of R-(-)-mandelic acid reached 97.2% and 100%, respectively. Kinetic models were developed for asymmetric reduction of ethyl benzoylformate and hydrolysis of (R)-(-)-mandelic acid ethyl ester. The kinetic models are in good agreement with the experimental data.
研究领域:
生物化学
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微生物学
·
有机合成
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC
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2013
·
IF 2.823
Jian-Yong Zheng,Jia-Yu Wu,Yin-Jun Zhang,Zhao Wang
The mycelium of Aspergillus oryzae WZ007 was successfully developed to kinetic resolution of ( R , S )-ethyl-2-(4-hydroxyphenoxy) propanoate (( R , S )-EHPP) for production of ( R )-ethyl-2-(4-hydroxyphenoxy) propanoate (( R )-EHPP). The key biocatalytic process parameters (pH, temperature, rotation speed and substrate concentration) were optimized. Under the optimum conditions, the optical purity of ( R )-EHPP was improved up to >99% when the conversion was above 49%. A. oryzae WZ007 whole-cell lipase exhibited high reaction capacity, enantioselectivity and good reusability. The tolerable substrate concentration was 0.5 mol/L, and dry mycelium of A. oryzae WZ007 maintains over 80% of its initial activity after eight repeating cycles. Therefore the enzymatic preparation of ( R )-EHPP route was suitable for industrial application.
研究领域:
生物化学
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微生物学
·
制药工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Energy Materials
·
2023
·
IF 6.4
Ke Wei,Jiu-Xiang Yang,Fang-Yuan Bai,Yuan-Sheng Shen,Kai Liu,Jing Liu,Li-Hua Chen,Yu Li,Bao-Lian Su
Ti3C2 MXene has been extensively studied in the field of photocatalytic hydrogen production since its discovery due to the large specific surface area and adjustable surface groups. However, the weak interaction at the interface of Ti3C2-based composites leads to a high energy barrier, which is not conducive to carrier transport. Herein, we propose the construction of a sandwich Ti3C2/R-TiO2 composite photocatalyst by in situ growing rutile TiO2 (R-TiO2) nanoneedles in Ti3C2 MXene through NaOH oxidation treatment and the microwave hydrothermal method. This in situ synthesis can make Ti3C2 MXene and TiO2 nanoneedles closely link together, which is conducive to carrier transport and material stability. The best Ti3C2/R-TiO2 composite achieves an excellent hydrogen production rate of 1.62 mmol g–1 h–1, as endowed by the 2D nanosheet-constructed sandwich structure, an increased specific surface area, and improved charge carrier separation and transport.
研究领域:
材料科学
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能源科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Scientific Reports
·
2019
·Vol. 9
·期 1
·1-11
·
IF 4.011
Chen Yang,Wang Xing,Yu Chao,Ding Jun,Deng Chengji,Zhu Hongxi
r-BN nanoflakes were synthesized using KBH 4 and NH 4 Cl as the main raw material in a high-purity nitrogen atmosphere. The effects of salt and salt-free conditions and heating temperature on the synthesis of BN were studied. The molten-salt method was used to synthesize BN at 650 °C, which was 250 °C lower than the BN synthesis method without salt. Furthermore, at 1000 °C the prepared flake-like BN crystals showed good crystallinity, uniform morphology, a particle diameter of 200–300 nm, and a thickness of 40–70 nm. Moreover, the specific surface area of BN was 294.26 m 2 /g. In addition, the BN synthesized at 1100 °C had a large elastic modulus value and good oxidation resistance.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Qi Yuan,Sen Wang,Gaobin Liu,Shuai Yan
Microwave dielectric ceramics (MWDCs) are prone to mechanical failure, and improving the mechanical properties of MWDCs is of significance for their application under extreme conditions. Novel high-entropy R(Nb 1- x Ta x ) 2 O 6 (R = Mg 0.2 Mn 0.2 Co 0.2 Ni 0.2 Zn 0.2 ) ceramics were prepared by the solid-phase reaction method. The single-phase and composite solid solutions of the R(Nb 1- x Ta x ) 2 O 6 series were successfully prepared, as evidenced by XRD, Raman spectra, and combined with EDS energy spectrum analysis. The average grain size was found to increase with the Ta 5+ content, while the grain dispersion exhibited a trend of increasing and then decreasing, resulting in a trend of increasing and then decreasing Q× f . The replacement of Nb 5+ by Ta 5+ has been demonstrated to improve τ f and enhance the mechanical properties. An increase in Ta 5+ content from 0.5 to 0.75 results in a significant enhancement in ε r and mechanical properties, which is primarily attributed to the generation of the RTa 2 O 6 phase. When x = 1, the R(Nb 1- x Ta x ) 2 O 6 ceramics exhibit excellent microwave dielectric properties (ε r = 31.28, Q× f = 20,722, τ f = 48.36) and the most favorable mechanical properties ( H v = 7.99 GPa, σ = 882 MPa, TRS = 237.7 MPa). This study provides a new idea to improve the mechanical properties of MWDCs.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2025
·
IF 5.2
Tianwen Fan,Pingting Zhuang,Liangbin Lin,Hongyu Guo,Fafu Yang
The construction of high CPL (circularly polarized luminescent) materials in aggregated state is of great significance but rarely reported. In this work, series of CPL active materials based on R-binaphthol-cyanostilbene were designed and synthesized in yields of 73–78 %. They emitted strong fluorescence in aggregated state but the CPL emissions were at moderate level of 1.42–4.52 × 10 −3 for g lum values. However, as these CPL materials was added into 4-cyano-4′-n-pentylbiphenyl (a commercial nematic liquid crystal), the high CPL emissions in aggregated state were observed for these doped materials. An interesting chirality inversion was distinguished under the different doping concentrations. The g lum values of CPL emission for these CPL materials with pentyl, octyl and dodecyl groups were as high as 0.29, 0.35 and 0.23, respectively, and the corresponding absolute fluorescence quantum yields were 0.42, 0.44 and 0.41 at the doping concentration of 4 %, exhibiting the good application prospect for these doping commercial liquid crystals.
研究领域:
材料科学
·
光学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Xiaodong Yang,Xueqin Shao,Jin Tong,Jinfeng Zhou,Ying Feng,Rui Chen,Qiang Yang,Ye Han,Xizhen Yang,Lili Wang,Xuewen Ma,Zhongqing Fan,Zhi Song,Andrew R. Zimmerman,Bin Gao
Advanced clay sorbents have attracted widespread attentions for applications in environment remediation and pollution control. Here, a facile and environmentally-friendly approach to synthesizing a porous Na-bentonite/hickory-biochar composite sorbent from hickory waste biomass using hand-milling and carbon-bed pyrolysis was investigated. The sorbents, made using a range of clay/biomass ratios and at a range of temperatures, were characterized and examined for their ability to remove Eriochrome blue black R (EBBR) anionic organic dyes from aqueous solution. The composite sorbents showed increased microporosity and O-containing functional groups over the pyrolyzed bentonite control. The composite prepared with 10% biomass by weight, and at 600 °C had the greatest EBBR adsorption, and was best fit to Freundlich isotherm and intraparticle diffusion kinetics models. The modeled maximum EBBR sorption capacity of this composite (2020.5 mg g −1 , R2 adj = 0.92), which was attributed to the dispersion of bentonite particles over the biochar surface. These results show the bentonite/biochar composite to have great potential for use in environmental remediation applications.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2024
·Vol. 31
·期 19
·28525-28537
·
IF 0
Qiu Rui,Chen Aiyin,Zhang Peng,Tang Xuejiao,Wang Cuiping,Sun Hongwen
Herein, novel catalysts of Fe-containing zeolite-A (Fe/zeolite-A) were synthesized by exchanging iron ions into zeolite-A framework, and short-chain organic acids (SCOAs) were employed as chelating agents. Reactive Brilliant Blue KN-R (KN-R) was used as a model pollutant to evaluate the performance of these catalysts based on the heterogeneous Fenton reaction. The results showed that Fe-OA/3A, which applied zeolite-3A as the supporter and oxalic as the chelating agent, presented the most prominent KN-R decolorization efficiency. Under the initial pH of 2.5, 0.4 mM KN-R could be totally decolorized within 20 min. However, the mineralization efficiency of KN-R was only 58.2%. Therefore, anthraquinone dyes were introduced to modify zeolite-3A. As a result, the mineralization efficiency of KN-R was elevated to 92.7% when using Alizarin Violet (AV) as the modifier. Moreover, the modified catalysts exhibited excellent stability, the KN-R decolorization efficiency could be maintained above 95.0% within 20 min after operating for nine cycles. The mechanism revealed that the Fe(II)/Fe(III) cycle was accelerated by AV-modified catalyst thus prompting the KN-R decolorization in Fenton-like system. These findings provide new insights for preparing catalysts with excellent activity and stability for dye wastewater treatment.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
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