Scientific Reports
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2017
·Vol. 7
·期 1
·1-11
·
IF 4.259
Zhou Yang,Yuan Shaofei,Liu Qian,Yan Dandan,Wang Yun,Gao Li,Han Juan,Shi Haifeng
In this paper, an efficient and convenient Fe 3 O 4 /PMG/IDA-Ni 2+ nanoparticles that applied to purify and immobilize his-tagged β-glucosidase was synthesized, in which, Fe 3 O 4 /PMG (poly ( N, N’- methylenebisacrylamide-co-glycidyl methacrylate) core/shell microspheres were synthesized firstly using distillation-precipitation polymerization, then iminodiacetic acid (IDA) was used to open epoxy rings on the shell of microspheres to the combination of Ni 2+ . The gene of β-glucosidase that was from Coptotermes formosanus Shiraki was amplified, cloned into the expression vector pET28a with an N-terminal His-tag, and expressed in E.coli BL21. The nanoparticles showed the same purification efficiency as commercial nickel column which was a frequently used method in the field of purifying his-tagged proteins from crude cell lysates. The results indicated that Fe 3 O 4 /PMG/IDA-Ni 2+ nanoparticles can be considered as an excellent purification material. β-glucosidase was immobilized on the surface of Fe 3 O 4 /PMG/IDA-Ni 2+ to form Fe 3 O 4 /PMG/IDA-β-glucosidase by means of covalent bound with imidazolyl and Ni 2+ . The immobilized β-glucosidase exhibited excellent catalytic activity and stabilities compared with free β-glucosidase. In addition, immobilized β-glucosidase can be recycled for many times and retain more than 65% of the original activity. The materials display enormous potential in the aspect of purifying and immobilizing enzyme.
研究领域:
生物化学
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生物技术
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酶学
·
纳米技术
✓ 已验证
DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2023
·
IF 5.2
Xiayu Liang,Qingle Zeng
Based on the Hard-Soft-Acid-Base theory, we developed and synthesized a unique crystalline adsorbent called MIL-101(Cr)-SMA-ED-PMG (SMA: styrene maleic anhydride; ED: ethylenediamine; PMG: N,N -di(phosphonomethyl)glycine). This adsorbent consists of polymer chains that are abundant in carboxyl and phosphate Lewis hard base groups. This was performed to enhance the efficient recuperation of electrophilic Lewis hard acid rare earth elements . The Neodymium(III) (Nd 3+ ) and Europium(III) (Eu 3+) ions reached adsorption equilibrium in the MIL-101(Cr)-SMA-ED-PMG material after 6 h at pH 5. The adsorption of Nd 3+ and Eu 3+ follows the pseudo-second-order kinetic and Langmuir models. The maximum adsorption capabilities were 102.7 mg/g for Nd 3+ and 110.4 mg/g for Eu 3+ . In addition, when applying a concentration of 0.3 mol/L of HNO 3 or HCl, the adsorbent was nearly completely desorbed, and it remained stable for five cycles. The order of adsorption for the different REE ions was as follows: Eu 3+ > Nd 3+ > Ce 3+ > La 3+ . The MIL-101(Cr)-SMA-ED-PMG compound demonstrated a remarkable 84 % selectivity in adsorbing Eu 3+ compared to the other metal ions in the mixture (Na + , Mg 2+ , Co 2+ , Ni 2+ , and Zn 2+ ). Furthermore, the adsorption of Eu 3+ was not significantly influenced by changes in the aqueous conditions. The experiment conducted on a zinc ore simulated leachate exhibited the material remarkable capacity for Eu 3+ separation and enrichment. MIL-101(Cr)-SMA-ED-PMG exhibits strong adsorption properties, exceptional selectivity, effective desorption, and significant potential for the recovery of rare earth elements (REEs).
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2024
·
IF 5.3
Yijie Wang,Guancheng Jiang,Qiannan Wang,Yinbo He,Lili Yang,Tengfei Dong,Xingxing Wang
In the development of deep shale oil and gas, the working temperature of the water-based drilling fluids is relatively high, which can cause wellbore instability due to the poor temperature resistance of the traditional environmental-friendly additives. To address this issue, this study presents a wellbore stabilizer called PMG, prepared by modifying gelatin (GT) with a resin synthesized by polyvinyl alcohol (PVA) and methacrylic acid (MA) through hydrothermal free radical polymerization, and it can withstand temperature up to 200 °C. The synthesis and thermal stability of PMG were confirmed by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). The wellbore stability performance of PMG was evaluated by linear swelling test, rolling recovery test, core immersion experiment and point load test and the wellbore stability mechanism was also investigated. The results reveal that the swelling height of sodium-based bentonite (Na-BT) in 2.0 % PMG solution at 150 °C is only 0.97 mm; the hot-rolling recovery rate in 2.0 % PMG solution at 200 °C is 72 %; the artificial core still maintains its original appearance after being immersed in 2.0 % PMG solution at 200 °C for 16 h, and the compressive strength increases by 12 %, effectively strengthening the wellbore. In addition, the EC 50 value of PMG is > 10 6 mg/L, and the BOD 5 /COD cr value is 31 %, indicating that it is non-toxic and biodegradable. PMG has excellent wellbore stability performance, in addition to being able to adsorb on the surface of Na-BT by electrostatic action and hydrogen bonding, the PMG micelles that precipitated from the aqueous solution due to the breaking of hydrogen bonds in the molecular chain at high temperature also form a film on the clay surface, aggregating and cementing the clay particles together, further enhancing the wellbore stability.
研究领域:
石油工程
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Financial Studies
·
2022
·Vol. 11
·期 1
·7
·
IF 0
Mosab I. Tabash,Umaid A. Sheikh,Ali Matar,Adel Ahmed,Dang Khoa Tran
The existing literature has explained the causality flow from the exchange rates toward the stock market without explaining the role of the economic crisis in effecting this nexus. This study examines the role of the financial crisis in affecting the nonlinear causality flowing from the exchange rates toward the stock market indexes of the ASEAN-5 region. The precrisis, postcrisis, and overall sample duration comprised 365, 650, and 1085 observations over the periods from January 2002 to January 2008, January 2010 to January 2020, and January 2002 to January 2020, respectively. The results showed that the conventional symmetrical panel ARDL (PARDL) model was not able to formulate long-run cointegration between currency value fluctuations and stock market indexes for both regimes, i.e., the post recessionary and pre recessionary periods. However, asymmetrical cointegration was established between the currency values and stock market indexes for the pre recessionary period and the overall sampling time frame by utilizing the panel-based NARDL framework (PNARDL). The study suggests practical implications for the exporters and importers to consider the regime as well as both the negative and positive shocks in the international dollar values while making forward contractual agreements.
研究领域:
计量经济学
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金融学
·
应用经济学
✓ 已验证
DOI
ACS Applied Materials & Interfaces
·
2013
·
IF 5.008
Yuting Zhang,Yongkun Yang,Wanfu Ma,Jia Guo,Yao Lin,Changchun Wang
A facile approach has been developed to synthesize Fe3O4/PMG (poly (N,N′-methylenebisacrylamide-co-glycidyl methacrylate)) core/shell microspheres using distillation–precipitation polymerization. Treating PMG shell with iminodiacetic acid (IDA) and Ni2+ yields composite microspheres of Fe3O4/PMG/IDA–Ni2+. The Ni2+ ions loaded on the surface of microspheres provide abundant docking sites for immobilization of histidine-tagged proteins. The high saturation magnetization of Fe3O4/PMG (23 emu/g), determined by vibrating sample magnetometer (VSM), allows an easy separation of the microspheres from solution under an external magnetic field. The composite microspheres were used to purify two His-tagged cellulolytic enzymes (Cel48F and Cel9G) directly from crude cell lysates with high binding affinity, capacity, and specificity. The microspheres can be recycled for many times without significant loss of binding capacity to enzymes. The immobilized enzymes on the surface of microspheres well retain their biological activities in degradation of cellulose. These materials show great potential in the biomedical and biotechnological applications that require low-cost purification of recombinant proteins and instant enzyme immobilization at an industrial scale.
研究领域:
生物技术
·
生物化学
·
材料科学
·
酶学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）