查找使用阿拉丁产品的科研文献

Heterogeneous Non-noble Catalyst for Highly Selective Production of Linear α-Olefins from Fatty Acids: A Discovery of NiFe/C

Zihao Zhang,Wenwen Lin,Yafei Li,Francis Okejiri,Yubing Lu,Jixing Liu,Hao Chen,Xiuyang Lu,Jie Fu

Graphical Bimetallic boost : A NiFe/C bimetallic catalyst is reported, composed of NiFe alloy in the material bulk and a surface mixture of NiFe alloy and oxidized NiFe δ + species, exhibiting a heptadecene yield of 70.1 % with selectivity to 1-heptadecene as high as 92.8 % at just 190 °C. Catalytic deoxygenation of even-numbered fatty acids into odd-chain linear α-olefins (LAOs) has emerged as a complementary strategy to oligomerization of ethylene, which only affords even-chain LAOs. Although enzymes and homogeneous catalysts have shown promising potential for this application, industrial production of LAOs through these catalytic systems is still very difficult to accomplish to date. A recent breakthrough involves the use of an expensive noble-metal catalyst, Pd/C, through a phosphine ligands-assisted method for LAOs production from fatty acid conversion. This study presents a unique, cost-friendly, non-noble bimetallic NiFe/C catalyst for highly selective LAOs production from fatty acids through decarbonylative dehydration. In the presence of acetic anhydride and phosphine ligand, a remarkable improvement in the yield of 1-heptadecene from the conversion of stearic acid was found over the supported bimetallic catalyst (NiFe/C) as compared to corresponding monometallic counterparts (Ni/C and Fe/C). Through optimization of the reaction conditions, a 70.1 % heptadecene yield with selectivity to 1-heptadecene as high as 92.8 % could be achieved over the bimetallic catalyst at just 190 °C. This unique bimetallic NiFe/C catalyst is composed of NiFe alloy in the material bulk phase and a surface mixture of NiFe alloy and oxidized NiFe δ+ species, which offer a synergized contribution towards decarbonylative dehydration of stearic acid for 1-heptadecene production.

Fabrication and postharvest application of alginate/pullulan composite films integrated with citral-loaded α-CD-MOFs for sustainable cherry storage

Mou Linyun,Li Jianlong,Lu Ya

Cherries are highly susceptible to spoilage after harvest due to physiological and biochemical changes. This poses considerable challenges to food safety. Common fungal pathogens responsible for decay include Aspergillus niger and Cladosporium cladosporioides . Citral, an efficient antifungal agent, is thought to combat these pathogens through interactions with phytase (phyA) and N-myristoyltransferase (NMT), a hypothesis explored through molecular docking simulations. Using the Independent Gradient Model based on Hirshfeld partition (IGMH) analysis, it was found that citral encapsulated within α -cyclodextrin metal-organic frameworks ( α -CD-MOFs) forms strong van der Waals forces and exhibits hydrogen bonding. These interactions enhance the stability of the composite material. Incorporating citral-loaded α -CD-MOFs into a matrix of sodium alginate and pullulan resulted in a novel composite film. This film exhibits significantly improved flexibility and tensile properties, which is beneficial for fruit packaging. Meanwhile, the Higuchi and Ritger–Peppas models both indicate that citral is released by diffusion from a uniform polymeric matrix. When applied to cherry preservation, the film exhibited significantly better cherry preservation at 4 °C than at 30 °C ( P  < 0.05). Simultaneously, the combination of low temperature with the film’s barrier properties and sustained antimicrobial release synergistically inhibited microbial growth and fruit metabolism, effectively delaying spoilage and supporting its application in both cold-chain and ambient-temperature transport.

Revealing the inhibition mechanism of ultrasound-assisted purified dried apricot polyphenols on α-amylase: Insights from multispectral and computational analyses

Cheng Ma,Zhongyang Li,Jiangli Lin,Bin Wu,Shuailian Zhao,Xiaojing Yao,Xiuling Zhu,Xiangyun Wei,Shishan Zhou

Ultrasound-assisted purification was employed to extract and refine polyphenols from dried apricots. The inhibitory mechanism of these ultrasonically purified polyphenols against porcine pancreatic α-amylase (PPA) was investigated through inhibition kinetics, fluorescence spectroscopy, circular dichroism (CD) spectroscopy, molecular docking, and molecular dynamics (MD) simulations. UHPLC–MS/MS analysis identified 19 phenolic compounds in the purified polyphenols (PP), with rutin, morin, and isoquercetin as the predominant constituents. Enzyme inhibition assays demonstrated that PP exhibited strong inhibitory activity (IC 50  = 3.46 ± 0.20 mg/mL) and acted as a mixed-type inhibitor, whereas the three monomeric polyphenols showed competitive inhibition. Fluorescence and CD analyses revealed that both PP and its major monomeric components induced conformational changes in the secondary structure of PPA by altering the hydrophobic microenvironment surrounding tryptophan and tyrosine residues, thereby reducing enzymatic activity. MD simulations confirmed the structural stability of the polyphenol-PPA complexes, and binding free-energy calculations indicated that rutin and isoquercetin exhibited stronger binding affinity and higher complex stability than morin, primarily mediated by hydrogen bonding and hydrophobic interactions. Collectively, this work provides a comprehensive understanding of the inhibitory mechanism of ultrasonically purified dried apricot polyphenols and their key constituents against PPA. These findings establish a theoretical basis for the efficient purification of polyphenolic compounds and their potential application as natural hypoglycemic agents.

Exploring the Reaction Mechanism of Efficient Electrochemical Nitrate Reduction to Ammonia over Carbon Cloth-Supported α-Co(OH)2 Nanosheets

Xiaoru An,Xiaonan Du,Hong Li,Fei Gao,Yue Hua,Xiuling Zhang,Jingsen Zhang,Lanbo Di

Electrochemical nitrate reduction reaction (eNO3RR) with Co-based catalysts provides a sustainable and efficient approach to wastewater purification and nitrogen recovery. However, their inevitable and uncontrollable reconstruction during the eNO3RR leads to uncertain actual active sites and a confused understanding of the mechanism. Herein, the active sites and structural evolution of α-Co(OH)2/CC during the eNO3RR process were investigated via in situ and ex situ characterizations. The results show that α-Co(OH)2 nanosheets are converted to β-Co(OH)2 in a strongly alkaline electrolyte and then act as active sites to adsorb NO3– and spontaneously react to generate CoOOH. Whereas CoOOH is swiftly reduced to β-Co(OH)2 at negative cathodic potential, realizing a nitrate-electrically mediated cyclic evolution process and synergistically catalyzing the eNO3RR. Consequently, α-Co(OH)2/CC achieves a Faradaic efficiency as high as 92% at −0.1 V vs RHE and a high NH3 yield rate of 338 mmol·gcat–1·h–1 under −0.6 V vs RHE. This work offers novel insight into the structural evolution and catalytic behavior of Co-based catalysts in eNO3RR.

Simultaneous determination of α-dicarbonyl compounds in Chinese Korean ethnic rice wine using pre-column derivatization with UHPLC-MS/MS

Xu Yinshuo,Han Zai-Gang,Zhang Minghui,Shi Qing,Min Jun Zhe

Chinese Korean ethnic rice wine (CKRW), a traditional fermented wine made from rice or corn, has antioxidant and antihypertensive activities. There is no report on the study of α-Dicarbonyl compounds (α-DCs) in CKRW currently. The sensitive UHPLC-MS/MS method based on a novel derivatization reagent 3-benzyl-2-oxo-4λ3-thiazolidine-4-carbohydrazide (BOTC). It was used to label three α-DCs, including glyoxal (GO), methylglyoxal (MG) and 3-deoxyglucoside (3-DG) in rice wine. The calibration curves obtained good linearity (R 2  > 0.9997) and a relatively wide range of concentrations from 0.39 to 62.5 µM. LOD were 25–50 fmol. GO, MG, and 3-DG were detected in CKRW for the first time. Then, ten kinds of rice wine were purchased from five suppliers for quantitative comparison. At the result, the contents of the three α-DCs had differences in these wines. 3-DG was higher than the other two α-DCs. The method provided a reference for the detection of α-DCs in other fermented alcoholic drinks. Graphical abstract

α-amylase-assisted spherical starch nanoparticles production from waxy rice starch by pullulanase debranching and nanoprecipitation: Structural and functional insights

Ri Chen,Jingjing Zhao,Zhongquan Sui,Dganit Danino,Harold Corke

In this study, α-amylase was used to assist starch nanoparticles (SNP) production through debranching and nanoprecipitation. The molecular structure, aggregation behavior, morphological properties, and digestibility of SNP were investigated. α-amylase hydrolysis pretreatment for 4 h increased the short-chain ratio of SNP, with a peak at DP = 13. This facilitated the formation of smaller and more uniform SNP, particularly at higher antisolvent concentrations. With α-amylase pretreatment, the small molecules reduced steric hindrance and interparticle interaction, resulting in a compact structure and well-defined boundaries during nanoprecipitation as indicated by cryo-EM. The crystalline pattern was mostly influenced by the solvent-to-antisolvent ratio. Prolonging α-amylase hydrolysis time led to loss of long-range crystalline order in SNP, while promoting the formation of submicron crystallites. Additionally, pretreatment increased slowly digestible starch and resistant starch ratios, leading to a lower glycemic response, thereby improving their functional performance. These findings offer valuable insights for optimizing the nanoprecipitation to produce SNP with controlled size and morphology, which enhances their potential as carriers in delivery systems.

Fabrication of dual Z-scheme MIL-53(Fe)/α-Bi2O3/g-C3N4 ternary composite with enhanced visible light photocatalytic performance

Yuqi Cui,Li-chao Nengzi,Jianfeng Gou,Yan Huang,Bo Li,Xiuwen Cheng

Z-scheme heterojunction photocatalyst can simultaneously reduce the recombination of photo-generated electron-hole pairs and preserve its outstanding redox ability during the process of photocatalytic reaction. In this study, Z-scheme MIL-53(Fe)/α-Bi 2 O 3 /g-C 3 N 4 photocatalyst was successfully fabricated via an accessible method and comprehensive characterized by XRD, FT-IR, SEM, TEM, XPS, N 2 adsorption-desorption isotherms, UV–vis diffuse reflection spectroscopy and photoelectrochemical analysis. The as-obtained MIL-53(Fe)/α-Bi 2 O 3 /g-C 3 N 4 composite exhibited superior photocatalytic activity for amino black 10B degradation than that of pure g-C 3 N 4 , α-Bi 2 O 3 , MIL-53(Fe) and α-Bi 2 O 3 /g-C 3 N 4 binary composite under visible light irradiation and the photodegradation rate would achieve the maximum when the mass fraction of MIL-53(Fe) was 32% in ternary composite. The enhanced photocatalytic performance of MIL-53(Fe)/α-Bi 2 O 3 /g-C 3 N 4 ternary composite could be mainly ascribed to improved visible light absorption range and the construction of an effective interfacial heterojunction driven by direct solid-state dual Z-scheme mechanism, which significantly facilitates the separation and transfer of photo-generated charge carriers. Eventually, the as-prepared ternary composite was confirmed to have prominent stability and reusability after consecutive 4 recycling run.

Boosting room-temperature ppb-level NO2 sensing over reduced graphene oxide by co-decoration of α-Fe2O3 and SnO2 nanocrystals

Yaqing Zhang,Zhimin Yang,Liang Zhao,Teng Fei,Sen Liu,Tong Zhang

As promising sensing materials, reduced graphene oxide (RGO)-based nanomaterials have drawn considerable attention in the fields of gas monitoring owing to their low operating temperature. However, constructing RGO-based room-temperature gas sensors possessing ppb-level limit of detection with high sensitivity remains challenging. In this work, a series of highly sensitive NO 2 sensors were fabricated using α-Fe 2 O 3 and SnO 2 co-decorated RGO hybrids (designated as α-Fe 2 O 3 /SnO 2 -RGO) as sensing materials. They were rationally synthesized by a one-pot hydrothermal method. Compared to SnO 2 modified RGO hybrids (SnO 2 -RGO with bandgap of 3.88 eV), the bandgap energy of α-Fe 2 O 3 /SnO 2 -RGO hybrids (3.53 eV) was reduced by adding α-Fe 2 O 3; the narrower bandgap facilitated the sensing materials to release more electrons and form more oxygen ions at room temperature. Besides, the high carrier migration of RGO, which served as continuous phase, identical structure with ultrasmall particle size of α-Fe 2 O 3 and SnO 2 (about 3–6 nm), and abundant chemisorbed oxygen species on the surface (20.8%) of the sensing materials, as well as their suitable bandgap (3.53 eV) in the sensing materials, significantly improved NO 2 response at room temperature. Among the sensors fabricated, α-Fe 2 O 3 /SnO 2 -RGO-15-based NO 2 sensor had the highest response of 7.4 with a short response time of 59 s towards 1 ppm NO 2 ; it could even reach a response of 2.6 towards 100 ppb NO 2 . Notably, α-Fe 2 O 3 /SnO 2 -RGO-15 sample has excellent capability to recognize NO 2 , where the response value (7.4) towards 1 ppm NO 2 is about 7 times higher than that of 100 ppm ammonia and common volatile organic compounds (formaldehyde, toluene, ethanol and acetone). Such NO 2 sensor has superior repeatability with negligible response deviation towards 1 ppm NO 2 for four reversible cycles. This makes it to have a great potential application in the field of NO 2 detection.

Potential hypoglycemic and hypolipidemic bioactive constituents in Cyclocarya paliurus leaves explored by affinity ultrafiltration with α-glucosidase and pancreatic lipase

Mengjia Xu,Huixia Feng,Mingquan Guo

Cyclocarya paliurus has been widely applied for therapeutic feeding as a traditional Chinese medicine homologous food with high nutritional and medical value. Nevertheless, the specific bioactive compounds liable for hypoglycemic and hypolipidemic properties and underlying mechanisms remain unexplored. In the present study, the in vitro hypoglycemic and hypolipidemic effects of C. paliurus were assessed by α-glucosidase and pancreatic lipase inhibition assays, and the results indicated that 70% ethanol extract exhibited remarkable α-glucosidase and pancreatic lipase inhibitory activity with the IC 50 value of 3.14 μg/mL and 0.98 μg/mL, respectively. A total of 18 and 15 potential ligand candidates were screened, and the chemical structures were characterized. Furthermore, the docking result showed that chlorogenic acid, quercetin, kaempferol 3- O -rhamnoside, and pterocaryoside A contributed to the underlying hypoglycemic and hypolipidemic effects of C. paliurus , further strengthened the bindings of the enzyme-ligand complex and suppressed the enzyme's activity with the binding energies ranged from −4.00 to −6.31 kcal/mol. The interrelations between the specific bioactive constituents, α-glucosidase or lipase, and hypoglycemic or hypolipidemic activities were also carified. The present study reveals substantial prospects of C. paliurus to be developed as a natural dietotherapy, disease-prevention, and healthcare for diabetes and obesity in the near future.

Metabolomic Profiling of Mice Exposed to α-amanitin Using Ultra-performance Liquid Chromatography Quadrupole Time-of-flight Tandem Mass Spectrometry

Lei Li,Chong Zheng,Jian Fang Ye,Kai Zhu,Yi Bing Zhou,Jia Liu,Ming Gao,Yu Tian Wu,Yong Ting Liu,Li Ya Liu,Ye Lin,Hai Chang Li,Quan Zhang,Hua Guo

A colorimetric sensing strategy based on chitosan-stabilized platinum nanoparticles for quick detection of α-glucosidase activity and inhibitor screening

Yang Qin-Qin,He Shao-Bin,Zhang Yi-Lin,Li Min,You Xiu-Hua,Xiao Bo-Wen,Yang Liu,Yang Zhi-Qiang,Deng Hao-Hua,Chen Wei

α-Glucosidase (α-Glu) is implicated in the progression and pathogenesis of type II diabetes (T2D). In this study, we developed a rapid colorimetric technique using platinum nanoparticles stabilized by chitosan (Ch-PtNPs) to detect α-Glu activity and its inhibitor. The Ch-PtNPs facilitate the conversion of 3,3′,5,5′-tetramethylbenzidine (TMB) into oxidized TMB (oxTMB) in the presence of dissolved O 2 . The catalytic hydrolysis of 2-O-α- d -glucopyranosyl- l -ascorbic acid (AA-2G) by α-Glu produces ascorbic acid (AA), which reduces oxTMB to TMB, leading to the fading of the blue color. However, the presence of α-Glu inhibitors (AGIs) hinders the generation of AA, allowing Ch-PtNPs to re-oxidize colorless TMB back to blue oxTMB. This unique phenomenon enables the colorimetric detection of α-Glu activity and AGIs. The linear range for α-Glu was found to be 0.1–1.0 U mL −1 and the detection limit was 0.026 U mL −1 . Additionally, the half-maximal inhibition value (IC 50 ) for acarbose, an α-Glu inhibitor, was calculated to be 0.4769 mM. Excitingly, this sensing platform successfully detected α-Glu activity in human serum samples and effectively screened AGIs. These promising findings highlight the potential application of the proposed strategy in clinical diabetes diagnosis and drug discovery. Graphical

On-chip single column transient isotachophoresis with free zone electrophoresis for preconcentration and separation of α-lactalbumin and β-lactoglobulin

Agustín G. Crevillén,Mercedes de Frutos,José Carlos Diez-Masa

Isotachophoresis (ITP) coupled to zone electrophoresis (ZE), either free zone electrophoresis (FZE) or gel electrophoresis (GE), carried out mainly in capillaries and, although less frequently, also in microchips, is a powerful preconcentration and separation technique which has been successfully used for the study of many low molecular-weight analytes. However, this analytical technique has been scarcely applied for proteins separation. In this work, an on-chip transient ITP coupled to free zone electrophoresis (t-ITP-MFZE) mode with LIF detection is developed for the preconcentration and separation of the proteins α-lactalbumin and β-lactoglobulin. Firstly, for LIF detection, the proteins were off-chip fluorescently labeled with the fluorogenic reagent Chromeo P503. Then, several separation parameters in t-ITP-MFZE mode such as leading electrolyte, terminating electrolyte, separation voltage, and injection time were optimized to achieve the maximum sensitivity while maintaining an adequate resolution between α-lactalbumin and β-lactoglobulin in a single column configuration t-ITP. Using the optimized electrolytes (50   mM imidazole/HCl pH   =   8 as leading electrolyte and 100   mM imidazole/12   mM HEPES pH   =   8 as terminating electrolyte) separation of both proteins was achieved in less than 4   min with peak resolution of 1.5. The LODs were 55   nM and 380   nM, for α-lactalbumin and β-lactoglobulin, respectively, which are adequate for some food allergenicity studies. Finally, comparison of the optimized t-ITP-MFZE method to the equivalent MFZE method, carried out also in microchips but without the isotachophoretic preconcentration step, provided preconcentration indexes for both proteins around 10.