PROCESS BIOCHEMISTRY
·
2021
·
IF 3.757
Huabiao Miao,Rui Jiang,Nanyu Han,Yu Ma,Qian Wu,Yuelin Mu,Zunxi Huang
Amylases have been widely applied for starch saccharification in the food, paper, pharmaceutical, and textile industries. In the present study, α-amylase DL-3-4−1 from B. amyloliquefaciens was successfully expressed in B. subtilis. The enzymatic activity exhibited high stability in a pH range from 4.0 to 11.0 and moderate thermostability. Furthermore, excellent stability was observed when incubated with metal ions, detergents, inhibitors, and organic solvents. Resistance against ethanol, urea, and guanidine−HCl was also observed. More importantly, a strategy to enhance the extracellular expression of α-amylase DL-3-4−1 was developed using 173 Sec-type signal peptides (SPs) as a library based on a fast and sequence-independent method. Fourteen SPs were identified with significantly increased yields of DL-3-4−1 via a high-throughput assay. Specifically, the enzymatic activity of the α-amylase-producing strain containing the signal peptide SP5D10 (YomL) was 3.74-fold higher than that of the strain with the wild type signal peptide (87.30 U/OD). In brief, the maximum specific activity of an α-amylase-producing strain containing the YomL signal peptide was 326.45 U/OD. This is the first report of an α-amylase that exhibits ethanol, urea, and guanidine−HCl tolerance. Hence, this α-amylase represents a promising candidate for future use in industry.
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COLLOIDS AND SURFACES B-BIOINTERFACES
·
2020
·
IF 4.389
Jin-Hua Xue,Ke-Ping Xiao,Yong-Sheng Wang,Ling Liu,Jia-Qian Li,Mei Li,Yue-Ning Qu,Xi-Lin Xiao
In this study, we confirmed that protamine-templated gold nanoclusters (PRT-AuNCs) exhibit aggregation-induced emission properties (AIE-PRT-AuNCs). 1-Hydroxypyrene (1−OHPy) further induced the aggregation of AIE-PRT-AuNCs via hydrogen bonding and electrostatic and hydrophobic interactions, resulting in the aggregation-induced photoluminescence enhancement of AIE-PRT-AuNCs. 9-Hydroxyphenanthrene was able to decrease the background signal, thus increasing the sensitivity of the method. Based on these findings, a cost-effective, highly sensitive and selective strategy was proposed for the quantitative detection of 1−OHPy. This method displayed a wide linear range of 0.924 – 74.1 nmol/L with a low detection limit of 0.277 nmol/L, showing great potential for the monitoring of 1−OHPy in human urine. This strategy may provide a theoretical basis for future studies of the AIE properties of metal nanoclusters and their applications in the field of chemical and biological sensing.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Shuang Qiu,Jinghua Du,Yonghou Xiao,Qidong Zhao,Gaohong He
Ultra-deep removal of thiophene sulfides from transportation fuel via adsorption has aroused great attention under the pressure of gradually demanding environmental regulations. The development of high-efficiency adsorbents is the key to adsorptive desulfurization for producing clean transportation fuels. In this work, a microwave-assisted synthesis method was applied to rapidly fabricate hierarchical porous defective HKUST-1 (DEHKUST-1) towards removing benzothiophene from model fuel by selective adsorption. The effects of cetyltrimethylammonium bromide (CTAB) dosage, adsorption temperature and adsorption contact time on the DEHKUST-1 desulfurization performance were systematically investigated. The characterization results proved that both metal clusters and linker defects were generated in the as-prepared DEHKUST-1. CTAB as template could modulate the pore distribution and introduce reasonable defects in the framework of HKUST-1. At CTAB: Cu 2+ = 0.5 by mole ratio, a regular mesoporous distribution of 25–30 nm could be obtained with DEHKUST-1; it exhibited an impressive enhancement in adsorptive desulphurization performance. The maximum adsorption capacity of the adsorbent attained 14.4 mg S/g adsorbent at 20 °C in 4 h. Even after CTAB-H-0.5 was regenerated six times, its adsorption capacity remained 93% as that of the as-prepared adsorbent. An adsorption mechanism was proposed to illustrate the promoting desulfurization performance by introduction of hierarchical porous in HKUST-1. By virtue of the rapid synthesis and remarkable benzothiophene removal capacity, the DEHKUST-1 could be a potential adsorbent in desulfurization from real fuels.
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JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 55
·期 7
·2741-2749
·
IF 3.442
Meng Cheng,Li Wenqi,Ren Chunrong,Zhao Junchuan
Powellite ceramic represents a waste form matrix material to immobilize minor actinides and Mo from reprocessed UMo nuclear fuel. In this paper, the Ca 1−x Li x/2 Gd x/2 MoO 4 (0 ≤ x ≤ 1) series is prepared by solid-state reaction using Gd 3+ as trivalent minor actinide (Cm 3+ ) surrogate, and the structure/microstructure is characterized by XRD, HRTEM, Raman spectroscopy and SEM. Rietveld refinements show that the couple (Gd 3+ and Li + ) enters into the eightfold coordinated Ca site of the powellite structure. With the increase in the contents of Gd and Li, Raman bands broaden due to the distortion of MoO 4 tetrahedra and disordered arrangements of Gd 3+ and Li + . The chemical durability analyzed by the PCT-B indicates that the leaching behaviors of Gd and Mo are related to the interfacial dissolution–reprecipitation mechanism. For the Ca 0.5 Li 0.25 Gd 0.25 MoO 4 ceramic, 7-day NL Gd and NL Mo are shown in the order of ~ 10 −4 and ~ 10 −4 g m −2 , respectively. Thus, our initial results of the structure and chemical durability will provide insights to design new single- or multiphase waste forms for the Mo-rich HLW conditioning.
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Polymers
·
2019
·Vol. 11
·期 3
·546
·
IF 3.164
Yanbin Wang,Huang Yu,Yongchao Li,Teng Wang,Tao Xu,Jinxing Chen,Zicheng Fan,Yufeng Wang,Biaobing Wang
Highly conductive thin films with suitable mechanical performances play a significant role in modern electronic industry. Herein, a series of ternary conductive polymer composites were fabricated by incorporating carbon black (CB) into binary conductive polymer composites of poly(amide-imide) (PAI) and polyaniline (PANI) to enhance their mechanical and conductive properties simultaneously. By varying the composition of PAI/PANI/CB ternary films, the conductivity enhanced by two orders of magnitude compared with the sum of PAI/PANI and PAI/CB binary conductive polymer composites, and a high conductivity of 1160 S m−1was achieved. The improved conductivity is mainly because much more continuous conductive networks were constructed in the ternary conductive polymer composites. With the help of the unusual morphology, the tensile strength was also enhanced by more than 80% from 21 to 38 MPa. The origin for the improved morphology was discussed for further improvement.Keywords:conductive polymer composite;ternary blend;poly(amide-imide);polyaniline;carbon black
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JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
·
2013
·
IF 3.187
Sheng-Jie Chen,Yong-Yong Wang,Wei-Min Yao,Xiao-Li Zhao,Giang VO-Thanh,Ye Liu
A novel ionic complex with insensitivity to moisture and air, bis-[1-butyl-2-diphenylphosphanyl-3-methylimidazolium]tetrachloridorhodium(III) hexafluorophosphate ( 1A ), has been synthesized and fully characterized. The single-crystal X-ray diffraction analysis shows that 1A is composed of the Rh(III)-complex cation and the counter-anion of PF 6 − . The complex cation has highly symmetrical Rh III -centered octahedron geometry with four Cl atoms in the equatorial plane and two imidazolium-substituted phosphine ligands in the axial position. The catalytic performance of 1A , which could be tailored by the ligands and the solvents, was investigated toward the biphasic hydroformylation of 1-octene. It was found that the presence of the hemilabile hybrid P,N-ligand of 3 (1-(2′-piperid-1′-yl-ethyl)-2-diphenylphosphino-3-methylimidazolium hexafluorophosphate), as a kind of ligand-functionalized ionic liquids (ILs), could dramatically spur the catalytic activity of 1A . The use of the RTIL of [PEmim]BF 4 (1-(2′-piperid-1′-yl-ethyl)-3-methylimidazolium tetrafluoroborate) as the solvent not only fulfilled the efficient biphasic hydroformylation of 1-octene, but also guaranteed the successful recovery and recycling of the ionic compositions of 1A and 3 .
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Food Analytical Methods
·
2022
·Vol. 15
·期 9
·2479-2486
·
IF 3.498
Zhang Shengnan,Li Zhibo,Qi Yanxia,Yu Pei,Zhao Qiancheng
The determination of 2-acetyl-1-pyrroline (2-AP), which is an important flavour compound of crustaceans and has a low odour threshold of 0.05 μg/L in water, is still a challenge due to the instability and trace levels of 2-AP in food samples. In this study, 2-AP was trapped by o-phenylenediamine and subsequently purified by the dispersive solid-phase extraction and dispersive liquid–liquid microextraction (DSPE-DLLME) methods for HPLC–UV analysis. The developed method was simple, fast and sensitive for the determination of 2-AP in shrimp. Under the optimized DSPE-DLLME conditions, the developed method exhibited excellent linearity ( R 2 = 0.996) and a low limit of detection (LOD, 1.77 μg/kg) and limit of quantitation (LOQ, 5.33 μg/kg). The recoveries of 2-AP in shrimp ranged from 86.3 to 101.6%. In addition, the developed method was applied to detect 2-AP levels in baked shrimp (ranging from 5.6 to 12.6 μg/kg), indicating that the formation of 2-AP could be observed in thermally treated shrimp depending on heating temperature and time. In summary, the developed method has potential application for the trace determination of 2-AP in shrimp due to its convenience and high sensitivity.
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Science of Advanced Materials
·
2016
·Vol. 8
·期 8
·1617-1627
·
IF 1.812
Wen Zhen,Su Jun-Qing,Chen Qing,Chen Li-Di
To improve the physicochemical and pharmacokinetic properties, solid lipid nanoparticles (SLNs) modified with (Polyethylene glycol-2000)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (PEG2000-DSPE) were prepared using glyceryl monostearate as a lipid carrier and resveratrol as a model
drug. Compared to ordinary SLNs, SLNs doped with low amount of PEG2000-DSPE [m(PEG2000-DSPE):m(lipids) = 1:5, w/w] exhibited improved physicochemical and pharmacokinetic properties, including higher entrapment efficiency (above 80%), smaller particle size (approximately 100 nm), more
distinguished drug release at low pH values (pH < 6.0), and longer drug circulation in vivo. According to the characterizations performed, the DSPE moiety was doped into lipid matrix to form a PEG2000-DSPE/lipid eutectic dopant, inhibiting lipid polymorphism transformation
from α-form to β-form, thereby preventing drug expulsion from the lipid. The dopant contained lattice defects, allowing for the incorporation of more resveratrol. Resveratrol was released in a sustained and pH-sensitive pattern due to nanoparticles destabilization
induced by partial protonation of PEG2000-DSPE. PEG chains distributed on the nanoparticle surface caused steric hindrance and “stealth” properties, thus maintaining dispersion stability and extending circulation time of nanoparticles. These results confirm that PEG2000-DSPE modification
effects are attributable to the matrix and surface structures of nanoparticles, which consist of a core containing DSPEinduced lattice defects and a shell coated with PEG chains.
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CARBOHYDRATE POLYMERS
·
2021
·
IF 9.381
Zhixiang Cai,Hongbin Zhang
The chain conformational change in curdlan during carboxymethylation was investigated using nuclear magnetic resonance (NMR), circular dichroism (CD) spectroscopy, and atomic force microscopy (AFM). The distributions of carboxymethyl substituents within anhydroglucose unit (AGU) of CMCD were found to follow the order of OH (6) > OH (4) > OH (2) for CMCD with a low DS and OH (6) > OH (2) > OH (4) for CMCD with relatively high DS. The increased carboxymethylation level induced the chain conformation transition of curdlan from triple helix to random coil in water. The DS of 0.25 was the critical value of chain conformation transition, below which CMCD chains were triple helices. For DS larger than 0.25, CMCD existed in the state of random coils. The intermolecular hydrogen bonding between C2 hydroxyls in AGU sustained the triple helical conformation and stiffness of the polymer chain, which weakened with the increase in DS.
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RUSSIAN JOURNAL OF COORDINATION CHEMISTRY
·
2014
·Vol. 40
·期 10
·764-767
·
IF 0.629
Li G. B.,Wang S. X.,Su W. Y.,Pan R. K.,Liu K. D.,Liu S. G.
A new cationic complex, [Co(Bpbp) 2 ](ClO 4 ) 2 · DMF · H 2 O, was synthesized by treatment Co(ClO 4 ) 2 · 6H 2 O with 2,6- bis (1-phenylbenzimidazol-2-yl)pyridine (Bpbp) in DMF solvent at room temperature. Its structure was characterized by element analysis, IR, and X-ray single crystal structure analyses (CIF file CCDC no. 970498). For complex, crystal system, triclinic, space group, \(P\bar \imath\) , a = 11.585(13), b = 13.939(16), c = 19.236(2) \(\mathop {\AA}\limits^\prime\) , α = 97.938(2)°, β = 102.814(2)°, γ = 90.556(2)°, V = 2861.1(6) Ǻ 3 , Z = 2. The Co 2+ ion octahedral geometry is coordinated by six nitrogen atoms from two ligand (Bpbp). The antiproliferative activities of the complex were screened by MTT assay against HepG2, Huh7, Eca109 and Eca9706 cancer cell. The complex exhibits inhibition on Eca9706 and Eca109 cancer cell but no HepG2 and Huh7 cancer cell.
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CHINESE JOURNAL OF CHEMICAL PHYSICS
·
2020
·Vol. 33
·期 6
·749-756
·
IF 1.067
Zhou Xue-zheng,Yan Xiang-yang,Zhu Ling,Ma Ming,Dai Ya,Wang Chang-guo,Zhu Li-jun,Yu Ke-jie,Liu Shao-min
A new kind of phenyl-functionalized magnetic fibrous mesoporous silica (Fe 3 O 4 @SiO 2 @KCC-1-phenyl) was prepared by copolymerization as an efficient adsorbent for the magnetic extraction of phthalate esters from environmental water samples. The obtained Fe 3 O 4 @SiO 2 @KCC-1-phenyl showed monodisperse fibrous spherical morphology, fairly strong magnetic response (29 emu/g), and an abundant π -electron system, which allowed rapid isolation of the Fe 3 O 4 @SiO 2 @KCC-1-phenyl from solutions upon applying an appropriate magnetic field. Several variables that affect the extraction efficiency of the analytes, including the type of the elution solvent, amount of adsorbent, extraction time and reusability, were investigated and optimized. Under optimum conditions, the Fe 3 O 4 @SiO 2 @KCC-1-phenyl was used for the extraction of four phthalate esters from environmental water samples followed by high-performance liquid chromatographic analysis. Validation experiments indicated that the developed method presented good linearity (0.1–20 ng/mL), low limit of detection (7.5–29 µg/L, S / N =3). The proposed method was applied to the determination of phthalate esters in different real water samples, with relative recoveries of 93%−103.4% and relative standard deviation of 0.8%–8.3%.
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MICROCHEMICAL JOURNAL
·
2022
·
IF 5.304
Dan Zhao,Xianfa Zhang,Wenjing Wang,Lili Sui,Xiaojing Bai,Haixiang Song,Chuanyu Guo,Yingming Xu,Xiaoli Cheng,Shan Gao,Lihua Huo
Early and painless detection of type-I diabetic patients by detecting acetone concentration in their exhaled breath would be a rapid and effective means. TiO 2 materials with exposed active (0 0 1) facet were synthesized mostly with HF as raw material, and the particle size was relatively large. In this work, (0 0 1) and (1 0 1) facets co-doped TiO 2 nanocubes with particle size < 50 nm were successfully prepared by a simple one-step hydrothermal process assisted by the ionic liquid ([Bmim][BF 4 ]) as the fluorine source and morphology modifier. Due to the exposure of the active (0 0 1) facets, the sensor exhibited good gas response to acetone gas at a low operating working temperature (OWT) of 170 °C with a detection limit as low as 30 ppb and a response time of only 2.2 s for 100 ppm acetone gas, and also relatively excellent selectivity, reproducibility, moisture resistance and long-term stability. It is worthy to point that, the changes of acetone concentration were compared in exhaled gas from healthy people and type-I diabetic patients, and the responses to exhaled gas of type-I diabetic patients were also tracked at different time in the same day. This provides significant convenience for early and painless diagnosis of type-I diabetic patients.
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