APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
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IF 22.1
Liuxin Xu,Ya Pan,Hongmei Li,Ruichao Xu,Zhihu Sun
The presence of interfacial sites between Pt-group metals and transition metal oxides can effectively improve the catalytic activity of Pt-group catalysts, but under moisture-rich conditions they suffer from severe deactivation due to water poisoning of the active sites. Here, we propose for the first time a Lanthanum (La)-doping strategy to improve the water-resistance of the Pt-based catalysts. We synthesized a Pt-CoO/Al 2 O 3 catalyst that is active for CO oxidation under dry conditions but deactivates rapidly under moisture. This rapid deactivation is overcome by La-doping, which delivers boosted activity (100 % CO conversion at 15 °C) and long-term on-stream stability. In situ X-ray absorption fine-structure and in situ diffuse reflectance infrared Fourier transform spectra revealed that the doped La, in the form of La 2 O 3 , plays dual roles of suppressing the carbonate formation on the active sites and modifying the electronic structure of Pt. The synergetic effects between La 2 O 3 and the active Pt−O−Co interfacial sites in La-doped Pt-CoO/Al 2 O 3 lead to the outstanding activity under the moisture-rich condition.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
Scientific Reports
·
2025
·Vol. 15
·期 1
·1-13
·
IF 3.9
Xue Juan,Meng Kun,Lv Jun,Liu Lanfang,Duan Fangfang,Ji Xuemeng,Ding Li
Cronobacter sakazakii is a Gram-negative bacterium known for causing severe infections in neonates, particularly through contaminated infant formula. This study investigated the role of the outer membrane lipoprotein NlpD in the environmental tolerance of C. sakazakii . A nlpD knockout mutant was constructed, and its impact on desiccation resistance, biofilm formation, motility, and proteomic profiles was evaluated and compared with that of the wild-type strain. The nlpD mutant presented reduced desiccation tolerance, reduced ability to form a biofilm, and altered surface hydrophobicity and motility patterns. The complemented strain restored these phenotypic changes, confirming that the observed effects were specifically due to the deletion of nlpD . Proteomic analysis revealed significant differential expression of proteins involved in metabolic and biosynthetic pathways upon nlpD deletion. These findings emphasize the multifaceted role of NlpD in enhancing the environmental tolerance of C. sakazakii , suggesting its importance in the resilience and survival of the bacterium in adverse conditions.
研究领域:
微生物学
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分子生物学
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产品关联
DOI
PubMed
高影响因子
FOOD MICROBIOLOGY
·
2025
·
IF 4.6
Ping Lu,Juan Xue,Aiying Shi,Xuemeng Ji
Cronobacter sakazakii is a notorious foodborne pathogen linked to severe infections in neonates, with powdered infant formula serving as a common transmission route due to its ability to survive under desiccated conditions. Understanding the molecular mechanisms underlying its desiccation resistance is crucial for developing effective control strategies. In this study, we employed comparative proteomics and hydropathy profiling to investigate putative core proteins potentially involved in desiccation resilience. Proteomic analysis of wild-type and 22 knockout strains identified 1,354 proteins, of which 156 were defined as putative core proteins due to stable abundance profiles. Among these, two uncharacterized proteins, ESA_03998 and ESA_01764 , exhibited strong hydrophilic properties and were predicted to be surface-associated based on signal peptide analysis. Gene knockout of ESA_03998 or ESA_01764 significantly reduced surface hydrophilicity and survival under prolonged desiccation in both PBS and milk powder matrices. Additionally, Laurdan-based membrane fluidity assays revealed increased membrane rigidification (ΔGP) in mutant strains, indicating that these proteins help preserve membrane hydration and dynamics under low-moisture conditions. These findings establish a novel link between hydrophilic putative core proteins and membrane-associated desiccation resistance in C. sakazakii , offering insights into its persistence in dry food environments and highlighting potential targets for mitigating contamination in powdered infant formula.
研究领域:
微生物学
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分子生物学
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食品科学
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产品关联
DOI
PubMed
高影响因子
INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY
·
2019
·
IF 3.618
Xiao-Jin Pei,Nan Chen,Yu Bai,Jian-Wen Qiao,Sheng Li,Yong-Liang Fan,Tong-Xian Liu
Insect cuticular hydrocarbons (CHCs), the evolutionary products of aquatic hexapod ancestors expanding to terrestrial environment, are deposited on the surface of insect integument and originally functioned primarily as waterproofing agents. CHCs are derived from the conserved fatty acid synthesis pathway in insects. However, the pivotal fatty acid synthase (FAS) involved in hydrocarbon (HC) biosynthesis remains unknown in many insect orders including the primitive Blattodea . Here, we investigated functional FAS genes that modulate cuticular lipid biogenesis in the German cockroach , Blattella germanica (L.). Based on our full-length transcriptomic data and the available genomic data, seven FAS genes ( BgFas1–7 ) were identified from B. germanica . Tissue-specific expression analysis revealed that BgFas1 , BgFas3 , BgFas4 and BgFas7 were highly expressed in the integument, whereas BgFas2 was dominantly expressed in the fat body. BgFas5 /6 mRNA was almost negligible in the tested tissues. Systemic RNAi screen was performed against BgFas1–7 , we found that only RNAi knockdown of BgFas1 caused a dramatic reduction of methyl-branched HCs (mbHCs) and a slight decrease of straight-chain HCs (scHCs) for both internal and external HCs. Significant reduction of cuticular free fatty acids (cFFAs) was also detected within BgFas1 -repressed cockroaches, while repression of CYP4G19 resulted in dramatic increase of cFFAs. Moreover, we found that BgFas1 mRNA levels were correlated with insect molting cycles, and could be induced by long-term mild dryness treatment. Furthermore, desiccation assay revealed that BgFas1 suppression accelerated water loss and led to early death of cockroaches under desiccation. Our results indicate that BgFas1 is necessary for both HC and cFFA biosynthesis in B. germanica . In addition, our study also confirms that cuticular lipids, particularly mbCHCs, are critical for desiccation resistance in B. germanica .
研究领域:
昆虫学
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分子生物学
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产品关联
DOI
PubMed
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2018
·Vol. 44
·期 5
·3135-3150
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IF 1.674
Wang Cheng-zhi,Zhao Yong-gang,Zhang Cheng,Yan Xin,Cao Peng
Honeycomb cordierite-based Mn–Ce/Al 2 O 3 (Mn–Ce/Al 2 O 3 –C) and Fe–Mn–Ce/Al 2 O 3 (Fe–Mn–Ce/Al 2 O 3 –C) catalysts were prepared by an impregnation method and investigated in low-temperature selective catalytic reduction (SCR) of NO with NH 3 at 100 °C. The Fe–Mn–Ce/Al 2 O 3 –C catalyst exhibited not only higher catalytic activity, but also much better SO 2 and H 2 O resistance in the presence of 30 ppm SO 2 and/or 5 vol% H 2 O than Mn–Ce/Al 2 O 3 –C. After doping Fe, the NO conversion of Mn–Ce/Al 2 O 3 –C catalyst displayed an increasing trend from 79 to 84% in the absence of SO 2 and H 2 O at 100 °C under a gas hour space velocity of 1667 h −1 . The results of characterization indicated that addition of Fe was advantageous to increase BET surface area, pore volume and inhibit loss of surface Mn and Ce species. Additionally, it was helpful for generating higher concentration of Mn 4+ , more chemisorbed oxygen and more uniform dispersion of amorphous Mn and Ce in the surface of catalyst, which were beneficial to interact with reactants. Furthermore, in contrast to Mn–Ce/Al 2 O 3 –C, the SCR activity of Fe–Mn–Ce/Al 2 O 3 –C catalyst in the presence of H 2 O, SO 2 and H 2 O and SO 2 were 79, 75 and 64%, with the increase of 14, 18 and 19%, respectively. It is indicated that the addition of Fe could inhibit sulfate formation and thus enhance SO 2 resistance. XPS results reveal that the doping of Fe into the ceria lattice led to some Ce 4+ transferred into Ce 3+ in order to maintain the electrical neutrality, thereby facilitating the reduction of Ce 4+ → Ce 3+ and the formation of oxygen vacancies. NH 3 temperature-programmed desorption (TPD) results imply that the doping of Fe onto Mn–Ce/Al 2 O 3 –C can remarkably improve the distribution and concentration of acid sites. All the above factors contributed to the improvement of overall NH 3 SCR performance of the Fe–Mn–Ce/Al 2 O 3 –C catalyst compared with that of the Mn–Ce/Al 2 O 3 –C catalyst.
研究领域:
环境科学
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催化化学
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产品关联
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
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2022
·
IF 7.926
Shuangli He,Jinghang Ren,Peng Cao
Low-temperature selective catalytic reduction (SCR) is effective and promising for converting NO x in flue gas into N 2 , with wide application prospects. However, low-temperature denitration (DeNO x ) catalysts are susceptible to SO 2 and H 2 O poisoning. Here, we prepared a monolithic Mn-Fe-Ce/Al 2 O 3 catalyst that exhibited excellent DeNO x performances at low temperatures. At 110 °C, the NO conversion rate of the catalyst was> 90%, exhibiting excellent resistances to H 2 O and SO 2 ·H 2 O and SO 2 are introduced at the same time, the efficiency is as high as 73%. Furthermore, The catalyst has a porous structure with abundant chemisorbed oxygen spices and exposed active, the reaction pathway on the catalyst proved to be the L-H mechanism based on in situ DRIFTS. This study also explored the mechanisms of low-temperature SCR catalyst poisoning by SO 2 and H 2 O, providing insights into the effects of SO 2 and H 2 O and theoretical support for the development of poisoning-resistant low-temperature SCR catalysts.
研究领域:
环境科学
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催化材料
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产品关联
DOI
高影响因子
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
2024
·
IF 1.6
Chengyu Zhou,Yani Wu,Yating Chen,Yuan Sun,Chunming Yang,Mengjie Yu,Dan Bao,Ying Xiao,Jie He
In order to solve the problem of drag reduction at the front end of shale fractures and sand carrying at the tail end with increased viscosity, the molecular dynamics simulation (MD) method was used to design polymer molecules and simulate the steric resistance, interaction potential energy, mean square displacement, and radial distribution function of the polymer. The polymer AM-AMPS-LMA-DiC 12 AM (ASLC12) with better solubility, diffusion, and resistance reduction potential was obtained and synthesized. By scanning electron microscope (SEM) and viscoelastic analysis, ASLC12 has a stable mesh structure, good viscoelasticity, and shear resistance, and the mesh structure formed by it is in a dynamic equilibrium state of fracture-reorganization under shear. We then analyzed the drag reduction, sand carrying, and salt resistance of ASLC12. When the concentration of ASLC12 is 0.09%, the sand-carrying requirement is satisfied. When the concentration is 0.05%, the drag reduction rate can reach 74.1%, and the resistance reduction rate of ASLC12 in salt ion solution can still reach more than 62%. This shows that the polymer ASLC12 has better sand carrying, drag reduction, and salt resistance.
研究领域:
聚合物科学
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材料科学
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流体力学
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分子模拟
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）