CHEMBIOCHEM
·
2022
·Vol. 23
·期 11
·e202200179
·
IF 3.461
Shiyi Song,Yingying Jiang,Ruidong Chen,Wencheng Su,Weinan Liang,Dameng Yang,Jincheng Li,Wuyuan Zhang,Shushan Gao,Bo Yuan,Ge Qu,Zhoutong Sun
Graphical Deacetoxycephalosporin C synthase (DAOCS) requires 2-oxoglutarate (2OG) as a co-substrate to catalyze the conversion of penicillin G to phenylacetyl-7-aminodeacetoxycephalosporin acid (G-7-ADCA). Catalase and L-GOX were introduced into the catalytic process of ring expansion to construct a 2OG production module to form a three-enzyme co-expression system, so as to realize the conversion of penicillin G to G-7-ADCA in vivo . Deacetoxycephalosporin C synthase (DAOCS) catalyzes the transformation of penicillin G to phenylacetyl-7-aminodeacetoxycephalosporanic acid (G-7-ADCA) for which it depends on 2-oxoglutarate (2OG) as co-substrate. However, the low activity of DAOCS and the expense of 2OG restricts its practical applications in the production of G-7-ADCA. Herein, a rational design campaign was performed on a DAOCS from Streptomyces clavuligerus (scDAOCS) in the quest to construct novel expandases. The resulting mutants showed 25∼58 % increase in activity compared to the template. The dominant DAOCS variants were then embedded into a three-enzyme co-expression system, consisting of a catalase and an L-glutamic oxidase for the generation of 2OG, to convert penicillin G to G-7-ADCA in E. coli . The engineered whole-cell enzyme cascade was applied to an up-scaled reaction, exhibiting a yield of G-7-ADCA up to 39.21 mM (14.6 g ⋅ L −1 ) with a conversion of 78.42 mol %. This work highlights the potential of the integrated whole-cell system that may inspire further research on green and efficient production of 7-ADCA.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2022
·
IF 24.319
Zhendong Zhao,Wenjun Zhou,Daohui Lin,Lizhong Zhu,Baoshan Xing,Zhiqi Liu
High metal loading of single-atom catalysts enables excellent catalytic activity, but possibly causes serious aggregation problem. Herein, a series of diatomic FeCo−N/C-x (x represents metal content) were skillfully designed and applied to improve the catalytic activity for peroxymonosulfate (PMS) activation toward degrading organic micropollutants. The unprecedented dual active sites, referring to Fe(N 3 )−Co(N 3 ) moiety and FeCo alloy, are constructed on the obtained FeCo−N/C-x, thereby exhibiting significantly greater performance toward degrading aqueous phenol (e.g., 0.316 min −1 for FeCo−N/C-3) via PMS activation, compared with those of traditional single-atom Co−N/C (0.011 min −1 ) and Fe−N/C (0.018 min −1 ). Combined experimental and theoretical calculations demonstrate the independent functions of dual active sites, in which Fe(N 3 )−Co(N 3 ) and FeCo alloy can decrease the energy barrier of O−O bond cleaving resulting in the formation of high-valent FeCo O reactive species and singlet oxygen, respectively. This study opens up a new platform toward constructing dual active sites for enhanced Fenton-like catalytic activity.
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ACS Omega
·
2022
·
IF 4.132
Lina Zhang,Ying Zhang,Baikang Zhu,Jian Guo,Dongguang Wang,Zhongqi Cao,Lihui Chen,Luhui Wang,Chunyang Zhai,Hengcong Tao
Electrochemical CO2 reduction has been acknowledged as a hopeful tactic to alleviate environmental and global energy crises. Herein, we designed an Fe@C/g-C3N4 heterogeneous nanocomposite material by a simple one-pot method, which we applied to the electrocatalytic CO2 reduction reaction (ECR). Our optimized 20 mg-Fe@C/g-C3N4-1100 catalyst displays excellent performance for the ECR and a maximum Faradaic efficiency (FE) of 88% with a low overpotential of −0.38 V vs. RHE. The Tafel slope reveals that the first electron transfer, which involves a surface-adsorbed *COOH intermediate, is the rate-determining step for 20 mg-Fe@C/C3N4-1100 during the ECR. More precisely, the coordinating capability of the g-C3N4 framework and Fe@C species as a highly active site promote the intermediate product transmission. These results indicate that the combination of temperature adjustment and precursor optimization is key to facilitating the ECR of an iron-based catalyst.
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高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2022
·Vol. 32
·期 26
·2111560
·
IF 19.924
Linlin Hu,Mihan Jin,Zhen Zhang,Haixia Chen,Farshad Boorboor Ajdari,Jiangxuan Song
Although Si and graphite (Si/C) composite materials are among the most promising alternative to graphite anode in commercial batteries because of high capacity, the issue of the poor structural and interfacial stability of the composite electrode is extremely challenging. Herein, an interface-adaptive triblock polymer binder that can interact Si and graphite particles to improve the particle affinity and binder spreadability via the supramolecular interactions of π∙∙∙π stacking and hydrogen bonding is presented. The strategy of enhancing the interfacial interactions can further effectively stabilize the electrode interface and minimize the electrode/electrolyte side reactions. Benefiting from this proposed binder, the Si/C anode retains a high reversible capacity (82.1%) after 400 cycles and delivers improved cycling stability even at high areal capacity (4 mAh cm −2 , 0.067% capacity loss/cycle) and in Si/C|LiNi 0.8 Co 0.1 Mn 0.1 O 2 full cell (0.22% capacity loss/cycle). This design strategy for the binder provides a novel path toward high-energy, long-cycling Si/C anodes.
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JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
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2022
·Vol. 106
·期 2
·393-405
·
IF 2.606
Dai Tao,Wu Zhanwu,Wang Zihan,Cui Sheng,Wu Xiaodong,Zhu Xiaofei
Fiber-reinforced aerogels with excellent properties such as low density and low thermal conductivity are potential thermal insulation materials. The slurry method and the embedding sintering method were used to fabricate MoSi 2 -aluminoborosilicate glass coatings on the surface of a carbon fiber-reinforced C-Al 2 O 3 aerogel composite under a low-oxygen atmosphere. The microstructure and phase composition of the coatings with different MoSi 2 contents before and after static oxidation were investigated. The resulting composite exhibited excellent radiating properties and outstanding oxidation resistance. The total emissivity of the as-prepared coatings was above 0.8185 in the wavelength range of 300–2500 nm. The sample with 40 wt% MoSi 2 in the outer coating had superior thermal endurance with a weight loss of only 0.54% after isothermal oxidation at 1200 °C for 180 min. This can be attributed to the optimum viscosity of the binder, which would relieve thermal stress defects and block oxygen diffusion. To further evaluate the thermal protection performance of the coatings, the heat transfer characteristics were simulated using the Fluent software package.
Graphical abstract
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MATERIALS & DESIGN
·
2022
·
IF 9.417
Wenqi Dong,Xueai Li,Huimin Tang,Kai Shi,Chunsheng Wang,Wanchun Guo,Kesong Tian,Haiyan Wang
The dielectric-magnetic synergistic effect can be achieved by dielectric relaxation and magnetic resonances in composites of carbon materials and magnetic particles. However, there is no direct evidence demonstrating the distribution of electromagnetic energy attenuation in the microstructure of composites. Herein, an amorphous carbon matrix with dispersed Fe/Fe 3 C@graphite-C was fabricated via a facile route. The distribution of the magnetic vector loss and electric vector loss in the hierarchical structures was revealed by numerical simulation. The content and dispersion of magnetic particles as well as the morphology of the amorphous carbon can be tuned. The 3D amorphous carbon matrix with highly dispersed Fe/Fe 3 C@graphite-C nanoparticles provided the strongest absorption of −69.0 dB and an effective response bandwidth (RL ≤ −10 dB) of 7.06 GHz. The numerical simulation revealed that the magnetic vector loss originated only from the core of Fe/Fe 3 C, and the electric vector loss was distributed throughout the structure, especially in the graphite-C shell, the interface between graphite-C and carbon nanoflakes, and the junction of different carbon nanoflakes. This work not only reveals the distribution of electromagnetic loss but also supports the theoretical analysis of the electromagnetic wave attenuation mechanism in composites, which provides direction for the future design of composites.
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Stem Cells International
·
2022
·
IF 5.131
Jinyong Chen,Feng Liu,Wangxing Hu,Yi Qian,Dilin Xu,Chenyang Gao,Zhiru Zeng,Si Cheng,Lan Xie,Kaixiang Yu,Gangjie Zhu,Xianbao Liu
Background. The poor survival rates of transplanted mesenchymal stem cells (MSCs) in harsh microenvironments impair the efficacy of MSCs transplantation in myocardial infarction (MI). Extrinsic apoptosis pathways play an important role in the apoptosis of transplanted MSCs, and Fas apoptosis inhibitory molecule (FAIM) is involved in regulation of the extrinsic apoptosis pathway. Thus, we aimed to explore whether FAIM augmentation protects MSCs against stress-induced apoptosis and thereby improves the therapeutic efficacy of MSCs. Methods. We ligated the left anterior descending coronary artery (LAD) in the mouse heart to generate an MI model and then injected FAIM-overexpressing MSCs (MSCsFAIM) into the peri-infarction area in vivo. Moreover, FAIM-overexpressing MSCs were challenged with oxygen, serum, and glucose deprivation (OGD) in vitro, which mimicked the harsh microenvironment that occurs in cardiac infarction. Results. FAIM was markedly downregulated under OGD conditions, and FAIM overexpression protected MSCs against OGD-induced apoptosis. MSCsFAIM transplantation improved cell retention, strengthened angiogenesis, and ameliorated heart function. The antiapoptotic effect of FAIM was mediated by cellular-FLICE inhibitory protein (c-FLIP), and FAIM augmentation improved the protein expression of c-FLIP by reducing ubiquitin–proteasome-dependent c-FLIP degradation. Furthermore, FAIM inhibited the activation of JNK, and treatment with the JNK inhibitor SP600125 abrogated the reduction in c-FLIP protein expression caused by FAIM silencing. Conclusions. Overall, these results indicated that FAIM curbed the JNK-mediated, ubiquitination–proteasome-dependent degradation of c-FLIP, thereby improving the survival of transplanted MSCs and enhancing their efficacy in MI. This study may provide a novel approach to strengthen the therapeutic effect of MSC-based therapy.
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高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Xinxin Ren,Qingbo Yu,Jia Pan,Qingping Wang,Yuqi Li,Naishen Shi,Shuli Deng
It is well known that the design of precursor structure is an effective method to optimize the photocatalytic activity of g-C 3 N 4 , and it will be interesting to investigate the relationship between the precursor structure and the structure of the target catalyst. In this paper, by adjusting the addition amount of glutaraldehyde (GA), three kinds of glutaraldehyde/dicyandiamide (GA/DCDA) precursors with equilibrium/imbalance hydrogen bond interaction can be obtained, and the carbonized glutaraldehyde (C-GA)/g-C 3 N 4 composite catalysts with different carbon content can be obtained after calcination. The obtained C-GA/g-C 3 N 4 composite catalysts have different photocatalytic activity for methylene blue degradation. Compared with the original g-C 3 N 4 , the photocatalytic activity of C-GA/g-C 3 N 4 -2 composite is increased by 2.69 times. Through the analysis of thermal decomposition kinetics and structural characterization, we can see that the equilibrium interaction in the structure of GA/DCDA-2 precursor can promote the conversion of dicyandiamide to melamine, and glutaraldehyde carbonization will form more C-GA, and form a composite catalyst with closer interaction with g-C 3 N 4 . C-GA with close interaction and higher content can effectively promote the separation of photogenerated carriers and visible light absorption, thus improving its photocatalytic activity.
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CARBON
·
2022
·
IF 11.307
Fangyu Gan,Qingrong Yao,Jianqiu Deng,Feng Wang,Lichun Cheng,Yucheng Chen,Huaiying Zhou,Yan Zhong,Huabin Yang,Yazhou Zhao
Layered double hydroxides (LDH) are employed as a promising template to prepare magnetic polymetallic alloys with hierarchical or hollow structure, being regarded as the promising candidates for the lightweight and high-performance electromagnetic wave (EMW) absorption materials . However, the application of LDH-derived magnetic alloys in EMW absorption is still limited by the single loss mechanism and poor impedance matching properties. Coupling with dielectric materials is a viable strategy to solve the issue. Herein, flower-like hierarchical FeNi@C microspheres are fabricated by pyrolysis of FeNi-LDH precursors, which display excellent EMW absorption performance . Good impedance matching and strong absorption capability of the FeNi@C microspheres can be realized by regulating the phase composition and microstructure under different pyrolysis temperatures. When pyrolyzed at 700 °C, the FeNi@C microspheres exhibit a strong reflection loss (RL) of −30.4 dB with ultra-thin matching thickness of only 1.2 mm, achieving the widest effective bandwidth (RL < −10 dB) of 4.6 GHz at 1.4 mm. The superior EMW absorption performance of the FeNi@C-700 sample is ascribed to the synergistic effects of hierarchical structure with multiple reflection, FeNi particles with magnetic loss and carbon matrix with dielectric loss. Thus, the as-obtained FeNi@C microspheres can be a prospective lightweight EMW absorber. This work can also provide guidance for design and development of hierarchical LDH derivatives in EMW absorption.
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BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR AND CELL BIOLOGY OF LIPIDS
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2022
·
IF 5.228
Weimin Lin,Lei Chen,Wenjing Meng,Kai Yang,Shengjuan Wei,Wei Wei,Jie Chen,Lifan Zhang
As a key adipogenic marker, C/EBPα (CCAAT/enhancer binding protein α) is also an important factor in regulating targets containing CCAAT element for transcription, whose products include coding and non-coding RNAs (ncRNAs). However, knowledge of the mechanism of C/EBPα affecting pre-adipocyte proliferation and adipogenesis through regulating ncRNA is still limited. In this study, we firstly conducted an investigation concerning the impact of C/EBPα knockdown on porcine pre-adipocytes by using RNA sequencing (RNA-Seq) to identify the role of key ncRNAs, especially lncRNAs and their correlated mRNAs in regulating proliferation and differentiation of porcine pre-adipocytes. 97 differentially expressed (DE) mRNAs and 4 DE lncRNAs were identified in si-C/EBPα groups compared with the si-NC groups. Meanwhile, we found C/EBPα directly target the promoter of a novel lncRNA , namely MSTRG.12568.2 , which was trans -correlated with STYX (serine/threonine/tyrosine interacting protein), an important candidate gene for regulating cell proliferation . Moreover, FOXO3 (forkhead box O3) was identified as a co-regulator with MSTR.12568.2 for STYX . Overexpression and knockdown of any of the MSTRG.12568.2 , STYX , and FOXO3 increased and decreased the levels of pre-adipocyte proliferation and differentiation, respectively, which demonstrated that they played a positive role in adipogenesis of pre-adipocytes. Furthermore, our results revealed that FOXO3 was necessary for MSTRG.12568.2 to trans -activate STYX . We revealed that C/EBPα regulated pre-adipocyte proliferation and differentiation through mediating trans -activation of MSTRG.12568.2 -FOXO3 to STYX . These results provide a novel regulation signal for C/EBPα to influence porcine pre-adipocyte proliferation and differentiation and greatly benefit to our understanding of molecular mechanism regulating subcutaneous adipogenesis.
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高影响因子
Nanoscale
·
2022
·Vol. 14
·期 29
·10566-10572
·
IF 8.307
Tongge Li,Haoyu Hu,Tonghui Cai,Xiaoqi Liu,Yixun Wang,Liying Wang,Yu Zhang,Wei Xing,Zifeng Yan
Rechargeable aluminum-ion batteries, RAIBs, as a prime candidate for next-generation batteries, have attracted much attention due to their extremely high anode capacity and good safety. However, the lack of matching high-capacity cathode materials and reasonable design limit their practical development. Herein, core–shelled Sb@C nanorods are prepared by polymer coating and thermal reduction as a metal-based cathode for RAIBs. The carbon shell and graphene aerogel interlayer effectively block the diffusion and shuttling of charging products, thus exhibiting excellent electrochemical performance. This Al–Sb battery delivers an initial discharge capacity of 656 mA h g−1 at 100 mA g−1, a stable discharge voltage of 0.9 V, and excellent cycling stability maintained at 306 mA h g−1 after 500 cycles at 1 A g−1. Serial characterizations are used to monitor the structural changes of Sb in reversible reactions and to determine the configuration of the charged products, showing that the product exists in the form of [SbCl4]+ cations, that is, a five-electron transfer reaction occurs with a very high theoretical capacity (1100 mA h g−1). This study sheds light on the energy storage mechanism of a metallic Sb cathode in RAIBs, and provides new insights into the study of high-capacity cathodes and the rational design of battery structures.
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JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Jie Chen,Jiafeng Wan,Chi Li,Yuhan Wei,Haolin Shi
Fe 0 -Fe 3 O 4 nanoparticles and cerium dioxide hollow spheres as efficient heterogeneous electro-Fenton reagents were rationally designed to be embedded in porous carbon derived from skimmed cotton for the electrocatalytic degradation of ceftriaxone sodium. Skimmed cotton porous carbon material has a hollow tubular structure, and cerium dioxide is dispersed on the surface of the carbon material in a hollow sphere structure of uniform size. Fe 0 -Fe 3 O 4 nanoparticles were wrapped in irregular particle shapes on the surface of cerium dioxide hollow spheres, and the remaining part was laid flat on the surface of porous carbon material. The as-synthesized Fe 0 -Fe 3 O 4 /CeO 2 /C showed excellent degradation efficiency of 95.59 % for ceftriaxone sodium within 120 mins and obtained a COD removal rate of 95.21 % at 240 mins. The zero-valent iron as a reducing agent effectively accelerated the Fe 3+ /Fe 2+ cycle, allowing the composites to exhibit higher catalytic activity and further reducing the possibility of secondary contamination. Moreover, the existence of cerium dioxide further promoted the redox cycle of Ce 4+ /Ce 3+ and accelerated the electron transfer in the interface of the catalyst. The synergistic effect of iron and cerium greatly facilitated the production of hydroxyl radicals and increased the yield of hydroxyl radicals in the reaction system.
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危险品化学品经营许可证（带存储）