查找使用阿拉丁产品的科研文献

Mass Spectrometry Imaging Strategy for In Situ Quantification of Soot in Size-Segregated Air Samples

Ke Min,Yong Li,Yue Lin,Xuezhi Yang,Zigu Chen,Bo Chen,Ming Ma,Qian Liu,Guibin Jiang

Soot, mainly derived from incomplete combustion of fossil fuel and biomass, exists ubiquitously in different environmental matrixes. To study the detrimental effects of soot on climate, air quality, and human health, accurate quantification of soot is an important prerequisite. However, until now, quantification of soot in environmental media, especially in carbonaceous media, is still very challenging. Here, we report a matrix-free laser desorption/ionization mass spectrometry (LDI-MS) method for in situ imaging of soot particles in size-segregated aerosol samples collected on filter membranes. A series of round-shaped sample spots in filter membranes were selected and subjected to MS imaging analysis, enabling direct in situ quantification of soot without solvent extraction or separation. Especially, the MS imaging with serial sample spots can overcome the problems of sweet-spot in LDI-MS and inhomogeneous distribution of soot in the filter membrane, thus greatly improving the precision of quantification. The limit of detection of soot was 4 ng/m2 and the recovery was 84.4–126%. By using this method, we found that a higher soot content was present in larger-sized particulate matter than smaller-sized particles, suggesting that aerosol soot was mainly derived from primary emission sources. Furthermore, this method also shows the potential to analyze nitrate and sulfate species in PM2.5. To the best of our knowledge, it is the first method capable of simultaneous analysis of inorganic salts and soot in air samples. It represents a novel strategy for in situ quantification of aerosol soot with the advantages of high specificity, high sensitivity, separation-, solvent- and matrix-free.

Functional Study on Cytochrome P450 in Response to L(−)-Carvone Stress in Bursaphelenchus xylophilus

Jie Chen,Xin Hao,Ruina Tan,Yang Li,Bowen Wang,Jialiang Pan,Wei Ma,Ling Ma

Bursaphelenchus xylophilus(PWN) causes pine wilt disease (PWD), which is one of the most devastating pine diseases worldwide. Cytochrome P450 (CYP) catalyzes the biosynthetic metabolism of terpenoids and plays an important role in the modification of secondary metabolites in all living organisms. We investigated the molecular characteristics and biological functions ofBx-cyp29A3inB. xylophilus. The bioinformatics analysis results indicated thatBx-cyp29A3has a transmembrane domain and could dock with L(−)-carvone. The gene expression pattern indicated thatBx-cyp29A3was expressed in 0.2, 0.4, 0.6, 0.8, and 1.0 mg/mL L(−)-carvone solutions. TheBx-cyp29A3expression increased in a dose-dependent manner and peaked at 24 h of exposure when the L(−)-carvone solution concentration was 0.8 mg/mL. However, the gene expression peaked at 0.6 mg/mL after 36 h. Furthermore, RNA interference (RNAi) indicated thatBx-cyp29A3played an essential role in the response to L(−)-carvone. The mortality rates of theBx-cyp29A3knockdown groups were higher than those of the control groups in the 0.4, 0.6, 0.8, and 1.0 mg/mL carvone solutions after 24 h of exposure or 36 h of exposure. In summary, bioinformatics provided the structural characteristics and conserved sequence properties ofBx-cyp29A3and its encoded protein, which provided a target gene for the study of the P450 family ofB. xylophilus. Gene silencing experiments clarified the function ofBx-cyp29A3in the immune defense ofB. xylophilus.This study provides a basis for the screening of new molecular targets for the prevention and management ofB. xylophilus.Keywords:cytochrome P450;L(−)-carvone;Bursaphelenchus xylophilus;RNAi

In Vitro and In Vivo Evaluation of Antidiabetic Properties and Mechanisms of Ficus tikoua Bur.

Hanlei Wang,Kun Zhang,Xuelin Chen,Mei Han,Jing Lu,Yumei Zhang

In folk medicine,Ficus tikoua(F. tikoua) has been used to treat diabetes for a long time, but there is a rare modern pharmacological investigation for its antidiabetic effect and mechanisms. Our study aimed to evaluate its hypoglycemic effect using in vitro and in vivo experimental models and then explore the possible mechanisms. In the ethanol extracts and fractions ofF. tikoua, n-butanol fraction (NBF) exhibited the most potent effect on inhibitingα-glucosidase activity (IC50= 0.89 ± 0.04 μg/mL) and promoting glucose uptake in 3T3-L1 adipocytes. Further animal experiments showed that NBF could play an antidiabetic role by ameliorating random blood glucose, fasting blood glucose, oral glucose tolerance, HbA1c level, and islets damage in diabetic mice. Then, the activities of the five subfractions of NBF (NBF1-NBF5) were further evaluated; NBF2 showed strongerα-glucosidase inhibition activities (IC50= 0.32 ± 0.05 μg/mL) than NBF. Moreover, NBF2 also possessed the ability to promote glucose uptake, which was mediated via P13K/AKT and AMPK pathways. This study demonstrated thatF. tikouapossesses antidiabetic efficacy in vitro and in vivo and provided a scientific basis for its folk medicinal use. NBF2 might be potential natural candidate drugs to treat diabetes mellitus. It is the first time the antidiabetic activity and the potential mechanisms of NBF2 were reported.Keywords:Ficus tikouaBur.;diabetes mellitus;α-glucosidase;3T3-L1 adipocytes;db/dbmice

Sensitive and Efficient Fluorescent Fiber-Optic Sensor for In-Situ Hypoxia Detection in Solid Tumor

Yang Wu,Minfeng Chen,Jiexuan Cai,Zhiyuan Xu,Fangzhou Jin,Yongkang Zhang,Wei Wang,Yang Ran,Dongmei Zhang,Bai-Ou Guan

Lifespan changes in cannabinoid 1 receptor mRNA expression in the female C57BL/6J mouse brain

Xulin Li,Gaoyang Zhao,Hongren Huang,Jialin Ye,Junfeng Xu,Yuan Zhou,Xiaojuan Zhu,Liping Wang,Feng Wang

Many brain functions that underlie behavior, cognition, and emotions vary with age, as does susceptibility to neuropsychological disorders. The expression of specific genes that are involved in these functions, such as the genes encoding for oxytocin, its receptors, and apolipoprotein D, varies with age across different brain regions. The cannabinoid 1 receptor (CB 1 R) is one of the most widely spread G-protein coupled receptors in the central nervous system and is increasingly recognized for its important contribution to various brain functions. Although changes in CB 1 R expression with age have been reported in the male mouse brain, they have not been well investigated in the female brain. Here, we used fluorescence in situ hybridization to target CB 1 R mRNA in the whole brains of female C57BL/6J mice aged 4, 6, 12, 52 (12 months) and 86 weeks (20 months), and quantified CB 1 R-positive cells in 36 brain regions across the whole brain. The results showed that CB 1 R-positive cells number changed with age. Specifically, CB 1 R expression increased with age in some subregions of the cortex, decreased with age in the lateral septal area, and reached its lowest level at 52 weeks in the thalamus, hypothalamus, and hindbrain subregions. Cluster analysis revealed that some brain regions shared similar temporal characteristics in CB 1 R-positive cell number across the lifespan. Our results provide evidence that investigation of the neural basis of age-related characteristics of female brain functions is not only warranted but required.

Improvement of in vivo efficacy of recombinant human erythropoietin by encapsulation in PEG–PLA micelle

Yanan Shi,Wan Huang,Rongcai Liang,Kaoxiang Sun,Fangxi Zhang,Wanhui Liu,Youxin Li

To improve the pharmacokinetics and stability of recombinant human erythropoietin (rhEPO), rhEPO was successfully formulated into poly(ethylene glycol)–poly(d,l-lactide) (PEG–PLA) di-block copolymeric micelles at diameters ranging from 60 to 200 nm with narrow polydispersity indices (PDIs; PDI < 0.3) and trace amount of protein aggregation. The zeta potential of the spherical micelles was in the range of −3.78 to 4.65 mV and the highest encapsulation efficiency of rhEPO in the PEG–PLA micelles was about 80%. In vitro release profiles indicated that the stability of rhEPO in the micelles was improved significantly and only a trace amount of aggregate was found. Pharmacokinetic studies in rats showed highly enhanced plasma retention time of the rhEPO-loaded PEG-PLA micelles in comparison with the native rhEPO group. Increased hemoglobin concentrations were also found in the rat study. Native polyacrylamide gel electrophoresis results demonstrated that rhEPO was successfully encapsulated into the micelles, which was stable in phosphate buffered saline with different pHs and concentrations of NaCl. Therefore, PEG–PLA micelles can be a potential protein drug delivery system.

Potassium-promoted Pt–In bimetallic clusters encapsulated in silicalite-1 zeolite for efficient propane dehydrogenation

Jie Zhou,Hao Liu,Chao Xiong,Peng Hu,Hao Wang,Xuyu Wang,Hongbing Ji

Propane dehydrogenation (PDH) has been a promising method to satisfy the increasing demand for propylene, but Pt-based catalysts always suffer from sintering and coke formation. Developing stable and efficient catalysts for PDH is of great significance for the industry. Herein, the paper reports that a catalyst with potassium-promoted Pt-In bimetallic clusters encapsulated in silicalite-1 (S-1) zeolite works as an efficient and stable catalyst for PDH. The catalyst achieves a propane conversion of 43.73 % with 97.14 % selectivity of propene and an extremely high propylene productivity of 20.33 mol g Pt -1 h -1 with a weight hourly space velocity (WHSV) of 6.75 h −1 . No obvious deactivation occurs after 48 h on stream, affording an extremely low deactivation constant of 0.0025 h −1 . The introduction of indium species greatly improves the propene selectivity and restricts the coke formation. The introduction of K + into S-1 can significantly enhance the catalytic activity and the stability of the catalyst. The catalyst with excellent activity and stability is potential for industrial application.

Bio-responsive composite liposomes against Campylobacter jejuni in vitro and its application in chicken preservation

Lin Lin,Canchao Mei,Xiaochen Chen,Changzhu Li,Zichun Hua,Haiying Cui

The infection of Campylobacter jejuni ( C. jejuni ) in food can cause huge economic and health costs, and liposomes based on biological switch is a promising antibacterial strategy. In this study, a bio-responsive composite liposome was designed with silk fibroin and L-fucose (FLPs) based on the chemotaxis and protease of C. jejuni , and Litsea cubeba essential oil as antibacterial agent. The oil encapsulation and protein mosaic rates of the composite liposome were 70.6 ± 0.5% and 47.9 ± 1.0%, respectively. The in vitro release experiment verified that the release rates of essential oil from the liposome exceeded 95% at 5 days. Furthermore, FLPs possessed excellent antibacterial activity , the inhibition zone was 23.5 mm and 20% ( v /v) of the composite liposomes could inactivate 99% C. jejuni . Moreover, laser scanning confocal microscopy and scanning electron microscopy images confirmed the antimicrobial activity of FLPs was better than that of other liposomes, and it could attach to bacteria well. Sprayed liposomes revealed sustained ability of retarding bacterial reproduction within 5 days with the refrigerated chicken meat inoculated with C. jejuni , and had no impact on the color and texture of the food. Hence, the bio-responsive composite liposome has a promising application in inhibiting C. jejuni growth in food. Industrial relevance In this study, the composite liposome with high encapsulation efficiency shows significant and sustained antibacterial activity, and has no negative effects on the color and texture of chicken meat. The findings of this study will facilitate the development and application of liposomes as active antimicrobial packaging in food industry.

Toxicity effects of chlorantraniliprole in zebrafish (Danio rerio) involving in liver function and metabolic phenotype

Zhiyuan Meng,Jiajia Cui,Li Liu,Chunmei Yang,Xin Bao,Jianjun Wang,Xiaojun Chen

Chlorantraniliprole (CAP), a representative bisamide insecticide, is widely used in rice fields around the world, posing potential toxicity risks to aquatic organisms . In this study, we examined the effects of exposure to CAP on growth and metabolic phenotype of zebrafish ( Danio rerio ) and oxidative stress and apoptosis in the liver of zebrafish ( Danio rerio ). First, we identified that CAP had a low bioaccumulation in zebrafish. Subsequently, growth phenotype analysis revealed that CAP could significantly increase liver weight and liver index in zebrafish. In addition, we found that CAP exposure could cause significant changes in indicators of oxidative stress, resulting in a significant increase in the content of malondialdehyde (MDA), causing oxidative stress in the liver of zebrafish. Meanwhile, the expression levels of apoptosis-related genes were also significantly changed and apoptosis was promoted in the liver of zebrafish with CAP exposure. Importantly, the results of metabolomics analysis shown that CAP exposure could significantly disrupt the metabolic phenotype of zebrafish, interfering with multiple metabolic pathways, mainly including valine , leucine and isoleucine biosynthesis and degradation, alanine , aspartate and glutamate metabolism and d -glutamine and D-glutamate metabolism. Last but not least, correlation analysis identified strong links between changes in liver function involving oxidative stress and apoptosis and changes in metabolic phenotype of zebrafish following CAP exposure. In brief, these results indicate that potential environmental risks of CAP to aquatic organisms should receive more attention.

In situ surface-enhanced Raman spectroscopy monitoring of molecular reorientation in plasmon-mediated chemical reactions

Binbin Zhou,Jing Zhong,Xinxue Tang,Jia-hua Liu,Junda Shen,Chong Wang,Weihui Ou,Hao Wang,Lu Liu,Jie Pan,Jian Lu,Yang Yang Li

Understanding the molecular orientation is crucial for revealing the mechanism of chemical reactions. However, how to accurately monitor the molecular orientation remains a great challenge because of the motion of the molecules during the chemical reaction. Here, surface-enhanced Raman spectroscopy (SERS) was used to monitor the molecular reorientation from the plasmon-catalyzed conversion of p-aminothiophenol (PATP) to p,p'-dimercaptoazobenzene (DMAB). Spectral change due to molecular reorientation, which is often overlooked, is clearly extracted through the protonation of the PATP molecules to suppress the conversion of PATP to DMAB. Meanwhile, by monitoring the Raman features, the reaction process and molecular reorientation are simultaneously recorded, offering fresh insights on the long-standing puzzle that why the conversion to DMAB is suppressed with concentrated PATP: this is because the over-crowded PATP adsorbed on the substrate hampered its own space-taking reorientation (similar to the space-steric effect) which is a prerequisite for producing DMAB.

Variation of Water Quality in Ningxia Section of the Yellow River in Recent 5 Years

Yan Jin,Xinyuan Wang,Ya-Ping Dong

The Yellow River is very important for human health and social development in China to require good water quality. This study selected the Ningxia section of the Yellow River as the study area to investigate the water quality variation in 2016–2020. A total of 9 water quality parameters were monitored, and 8 parameters including pH, dissolved oxygen, biological oxygen demand, chemical oxygen demand, total phosphate, fluoride, ammonia-nitrogen, and permanganate index were in the range of Class II standard requirement. Dissolved oxygen concentrations ranged from 7.5 to 9.4 mg/L. However, total nitrogen concentrations in 2018–2020 ranged from 1.87 to 2.8 mg/L to cause the pollution. Both the Nemerow index method and the contamination degree method showed that total nitrogen with high concentration exerted the water pollution. Principal component analysis also proved this. Stricter environmental management strategies for controlling total nitrogen should be taken in the future. The findings provided some useful information for water pollution of the Ningxia section of the Yellow River.

In situ grown rare earth lanthanum on carbon nanofibre for interfacial reinforcement in Zn implants

Mingli Yang,Yang Shuai,Youwen Yang,Da Zeng,Shuping Peng,Zongjun Tian,Cijun Shuai

Carbon nanofibre (CNF) is a potential reinforcement in Zn implants. Nevertheless, its poor interfacial compatibility reduces the reinforcement efficiency drastically. In this study, rare earth lanthanum (La) was used as a compatible interface layer between CNF and Zn matrix. On the one hand, La in situ grew on acidified CNF by a chemical synthesis and achieved a firm coordination covalent bond with the oxygenated functional group derived from CNF. On the other hand, La, as an active rare earth element, could carry out the alloying reaction with the Zn matrix, thus forming strong metal bonding. Results showed that the tensile strength of composites was enhanced from 180.2 ± 12.1 to 243.4 ± 10.2 MPa since the La interface layer promoted the transfer of the interfacial shear stress from the Zn matrix to CNF and thereby consumed massive fracture energy. Encouragingly, it simultaneously improved the ductility, as La activated basal slip and improved the dislocation accommodation capacity. Moreover, the Zn implants displayed excellent anti-tumour efficiency.