BACKGROUND The lack of specific predictors for type-2 diabetes mellitus(T2DM)severely impacts early intervention/prevention efforts.Elevated branched-chain amino acids(BCAAs:Isoleucine,leucine,valine)and aromatic amin...BACKGROUND The lack of specific predictors for type-2 diabetes mellitus(T2DM)severely impacts early intervention/prevention efforts.Elevated branched-chain amino acids(BCAAs:Isoleucine,leucine,valine)and aromatic amino acids(AAAs:Tyrosine,tryptophan,phenylalanine)show high sensitivity and specificity in predicting diabetes in animals and predict T2DM 10-19 years before T2DM onset in clinical studies.However,improvement is needed to support its clinical utility.AIM To evaluate the effects of body mass index(BMI)and sex on BCAAs/AAAs in new-onset T2DM individuals with varying body weight.METHODS Ninety-seven new-onset T2DM patients(<12 mo)differing in BMI[normal weight(NW),n=33,BMI=22.23±1.60;overweight,n=42,BMI=25.9±1.07;obesity(OB),n=22,BMI=31.23±2.31]from the First People’s Hospital of Yunnan Province,Kunming,China,were studied.One-way and 2-way ANOVAs were conducted to determine the effects of BMI and sex on BCAAs/AAAs.RESULTS Fasting serum AAAs,BCAAs,glutamate,and alanine were greater and high-density lipoprotein(HDL)was lower(P<0.05,each)in OB-T2DM patients than in NW-T2DM patients,especially in male OB-T2DM patients.Arginine,histidine,leucine,methionine,and lysine were greater in male patients than in female patients.Moreover,histidine,alanine,glutamate,lysine,valine,methionine,leucine,isoleucine,tyrosine,phenylalanine,and tryptophan were significantly correlated with abdominal adiposity,body weight and BMI,whereas isoleucine,leucine and phenylalanine were negatively correlated with HDL.CONCLUSION Heterogeneously elevated amino acids,especially BCAAs/AAAs,across new-onset T2DM patients in differing BMI categories revealed a potentially skewed prediction of T2DM development.The higher BCAA/AAA levels in obese T2DM patients would support T2DM prediction in obese individuals,whereas the lower levels of BCAAs/AAAs in NW-T2DM individuals may underestimate T2DM risk in NW individuals.This potentially skewed T2DM prediction should be considered when BCAAs/AAAs are to be used as the T2DM predictor.展开更多
The textural features and acidic properties of sulfated mesoporous lanthana‐zirconia solid acids (SO42?/meso‐La0.1Zr0.9Oδ) were efficiently tuned by modifying the conditions used to prepare the meso‐La0.1Zr0.9O...The textural features and acidic properties of sulfated mesoporous lanthana‐zirconia solid acids (SO42?/meso‐La0.1Zr0.9Oδ) were efficiently tuned by modifying the conditions used to prepare the meso‐La0.1Zr0.9Oδcomposites, such as the molar ratio of the template to La and Zr metal ions (Nt/m), molar ratio of ammonia to La and Zr metal ions (Na/m), hydrothermal temperature (Thydro), and hy‐drothermal time (thydro). The effect of the textural features and acidic properties on the catalytic performance of solid acid catalysts for alkenylation of p‐xylene with phenylacetylene was investi‐gated. Various characterization techniques such as N2 physisorption, X‐ray diffraction, NH3 temper‐ature‐programmed desorption, and thermogravimetric analysis were employed to reveal the rela‐tionship between the nature of catalyst and its catalytic performance. It was found that the catalytic performance significantly depended on the textural features and acidic properties, which were strongly affected by preparation conditions of the meso‐La0.1Zr0.9Oδcomposite. Appropriate acidic sites and high accessibility were required to obtain satisfactory catalytic reactions for this reaction. It was also found that the average crystallite size of t‐ZrO2 affected by the preparation conditions had significant influence on the ultrastrong acidic sites of the catalysts. The optimized SO42?/meso‐La0.1Zr0.9Oδcatalyst exhibited much superior catalytic activity and coke‐resistant stabil‐ity. Moreover, the developed SO42?/meso‐La0.1Zr0.9Oδcatalyst demonstrated excellent catalytic per‐formance for alkenylation of diverse aromatics with phenylacetylene to their correspondingα‐arylstyrenes. Combining the previously established complete regeneration of used catalysts by a facile calcination process with the improved catalytic properties, the developed SO42?/meso‐La0.1Zr0.9Oδ solid acid could be a potential catalyst for industrial production ofα‐arylstyrenes through clean and atom efficient solid‐acid‐mediated Friedel‐Crafts alkenylation of diverse aromatics with phenylacetylene.展开更多
The condensation of aromatic aldehydes with acidic methylene compounds such as malononitrile, methyl cyanoacetate, cyanoacetamide, 5,5-dimethyl-1,3-cyclohexanedione, bartbituric acid and 2-thiobarbituric acid proceede...The condensation of aromatic aldehydes with acidic methylene compounds such as malononitrile, methyl cyanoacetate, cyanoacetamide, 5,5-dimethyl-1,3-cyclohexanedione, bartbituric acid and 2-thiobarbituric acid proceeded very efficiently in water in the presence of triethylbenzylammonium chloride (TEBA) and the products were isolated simply by filtration.展开更多
Seven ternary Eu (m) complexes were synthesized with aromatic carboxylic acid (benzoic acid, phenylacetic acid, phenylpropionic acid and cinnamic acid) as the first ligand and 1,10-phenanthro- line or 2,2'-dipyri...Seven ternary Eu (m) complexes were synthesized with aromatic carboxylic acid (benzoic acid, phenylacetic acid, phenylpropionic acid and cinnamic acid) as the first ligand and 1,10-phenanthro- line or 2,2'-dipyridyl as the second ligand. The ternary Eu( Ⅲ ) complexes were characterized by elemental analysis, IR and TG-DTG methods. In these complexes, the Eu (Ⅲ) ions are bonded to the oxygen atoms of carboxylate and the nitrogen atoms of neutral ligands. Four complexes whose second ligand is 1,10- phenanthrolin have fine thermal stability. Excitation and luminescence spectra of the tide complexes reveal that the fluorescence of the complexes in which 1,10- phenanthrolin as the second ligand are more intensive than those complexes in which 2, 2'-dipyridyl as the second ligand. The order of the strongest emission peak of seven ternary complexes is: Eu(β-PPA)3phen 〉 Eu(BA)3phen 〉 Eu(PLA)3phen 〉 Eu(BA)3bipy 〉 Eu ( PEA)3bipy 〉 Eu ( CA )3phen · H2O 〉 Eu ( CA )3bipy (BA : benzoic ; PEA : phenylacetic ; β-PPA :展开更多
The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anio...The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy, and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.展开更多
The electrochemical-voltammetry behavior of vanillin, heliotropin, anisaldehyde on the surface of Pt, Au electrodes in acid solution has been studied by means of the electrochemical cyclic voltammetry method. It was f...The electrochemical-voltammetry behavior of vanillin, heliotropin, anisaldehyde on the surface of Pt, Au electrodes in acid solution has been studied by means of the electrochemical cyclic voltammetry method. It was found that the electrochemical processes of them are irreversible on both Pt and Au electrodes. The electrochemical activity of vanillin is stronger than heliotropin's and heliotropin's is stronger than anisaldehyde's on Pt electrode. While the electrochemical activity of anisaldehyde is stronger than heliotropin's and vanillin's is the weakest on Au. The results indicate that when they are used as additives for electroplating, they must be consumptive, and it will improve the leveling ability of plating solution and brightness of the deposition layer.展开更多
A method has been developed for separation of 20 kinds of aromatic carboxylic acid using anion-exchange chromatography. A Dionex IonPac AS9-HC guard column (250mm×2mm) was used with a 9mmol/L sodium carbonate s...A method has been developed for separation of 20 kinds of aromatic carboxylic acid using anion-exchange chromatography. A Dionex IonPac AS9-HC guard column (250mm×2mm) was used with a 9mmol/L sodium carbonate solution containing 50% (v/v) acetonitrile as eluent. A set of retention time data has been obtained using a conductivity detector DS6. Furthermore, geometrical optimization and electrostatic potential calculation of 20 kinds of aromatic carboxylic acid have been performed at the HF/6-31G* level of theory. A number of statistically-based parameters derived from molecular surface electrostatic potential have been obtained. Linear relationship between retention time and structural parameters has been established by multiple regression method. The result shows that parameters derived from electrostatic potential Vs +, Vs -, П together with the dipole moment μ can be well used to express the quantitative structure-retention time of this kind of aromatic carboxylic acid. Good predictive capability has also been demonstrated. The result has provided a framework which further proves the general applicability of this electrostatic potential parameter set to a great extent,and with which the ion chromatographic adsorption mechanism can be investigated.展开更多
This current study aims at determining the profile and contents of degradation compounds produced during the interaction between the frying oils and tuna fish involved in the cooking of “Garba”, a street food largel...This current study aims at determining the profile and contents of degradation compounds produced during the interaction between the frying oils and tuna fish involved in the cooking of “Garba”, a street food largely consumed in Côte d’Ivoire. For this purpose, the peroxide index and the neoformed compounds, especially trans fatty acids, acrylamid, polycyclic aromatic hydrocarbons were determined. This trial was carried out on 90 samples of frying oils and fried tuna fish collected from restaurant owners of “Garba” food in three locations in Abidjan. The samples were divided into three groups (G1, G2, and G3) according to the similarity of the practices adopted by the restorers. The results show that the peroxide values (14.95;15.01 and 11.97 meqO2/kg) of the oils respectively for G2, G3, and G1 are higher than the values fixed by the Codex Alimentarius. The trans fatty acid contents of the frying oils were 56.80%;61.01% and 55.18% respectively for G3, G2 and G1. The average acrylamide content of fried Tuna (69.43 μg/kg) is higher than the value recorded in the cooking oil (19.99 μg/kg). The average contents of the eleven HAPs determined in the oils are higher than those of the Tuna. The Benzo (a) pyrene contents of both matrices are lower than the EU standard 1881/2011 except for the G2 oil (2.66 μg/kg). Increased consumption of “Garba” may pose health risks to consumers as practices of frying Tuna generate compounds that are harmful to human health.展开更多
Monoamine neurotransmitters include catecholamines and indoleamines. The most common catecholamines are do- pamine (DA), noradrenaline (NA) and adrenaline, which are produced from phenylalanine and tyrosine; where...Monoamine neurotransmitters include catecholamines and indoleamines. The most common catecholamines are do- pamine (DA), noradrenaline (NA) and adrenaline, which are produced from phenylalanine and tyrosine; whereas the most common indoleamine is serotonin (5-hydroxytrypta mine, 5-HT), which is produced from 5-hydroxytryptophan (5-HTP).展开更多
The improvement of grain quality in aromatic rice is very important for farmer to increase their income.Present study was conducted with a two-year field experiment and three aromatic rice cultivars in order to study ...The improvement of grain quality in aromatic rice is very important for farmer to increase their income.Present study was conducted with a two-year field experiment and three aromatic rice cultivars in order to study the effects of exogenousα-ketoglutaric acid on yield formation,grain quality characters and the biosynthesis of 2-acetyl-1-pyrroline(2-AP,key component of aromatic rice’s fragrance)in aromatic rice.At heading stage,0.50 mmol L^(-1)(T1)and 1.00 mmol L^(-1)(T2)α-ketoglutaric acid solutions were overhead sprinkle to aromatic rice plants,respectively while the treatment which was overhead sprinkled with distilled water was set as control(CK).The results showed that 17.34%-33.04%and 21.39%-34.74%higher grain 2-AP contents were recorded in T1 and T2 treatments,respectively.Compared with CK,T1 and T2 treatments significantly reduced the transcript level of gene BADH2 which is related to the 2-AP biosynthesis in aromatic rice.3.86%-7.51%higher grain protein contents and 1.15%-3.37%higher head rice rates were also recorded inα-ketoglutaric acid treatments than CK.Moreover,T1 and T2 treatments remarkably decreased the chalky rice rate,chalkiness and grain amylose content.However,there was no remarkable difference in grain yield and related trails(effective panicle number,grain number per panicle,seed-setting rate and 1000-grain weight)among CK,T1 and T2 treatments.In conclusion,application of exogenousα-ketoglutaric acid enhanced 2-AP biosynthesis and improved grain quality of aromatic rice.展开更多
Action of bromine in concentrated nitric acid allows carrying out mono- and polybromination of moderately deactivated aromatic compounds. 4-Chloronitrobenzene and isophthalic acid turnes into 3-bromo-4-chloronitrobenz...Action of bromine in concentrated nitric acid allows carrying out mono- and polybromination of moderately deactivated aromatic compounds. 4-Chloronitrobenzene and isophthalic acid turnes into 3-bromo-4-chloronitrobenzene and 5-bromoisophthalic acid at reaction with bromine in concentrated nitric acid at 20°C whereas in absence of bromine in the same conditions 4-chloro-1, 3-dinitrobenzene and 5-nitroisophthalic acid are formed accordingly. Presence of bromine in concentrated nitric acid changes nitrating capacity to brominating one. Terephthalic acid and phthalic anhydride at heating with bromine in concentrated nitric acid can be transformed to appropriating tetrabromo substituted compounds.展开更多
Background:As type 2 diabetes mellitus(T2DM)biomarkers,branched-chain amino acids(BCAAs:valine,leucine and isoleucine)and aromatic amino acids(AAAs:phenylalanine,tryptophan and tyrosine)may be correlated with the occu...Background:As type 2 diabetes mellitus(T2DM)biomarkers,branched-chain amino acids(BCAAs:valine,leucine and isoleucine)and aromatic amino acids(AAAs:phenylalanine,tryptophan and tyrosine)may be correlated with the occurrence and development of T2DM.However,there is still no consensus on the disperse and isolated biomarkers of T2DM.Purpose:To explore the correlation between amino acids and T2DM based on integrated biomarker approach revealed.Methods:PubMed,Web of Science and CNKI were selected to search the literature published until August 31,2019.The included studies described the association between BCAAs,AAAs and T2DM.Random effect model and fixed effect model were adopted in pooled analysis to determine mean difference and 95 percent confidence interval of metabolites.Integrated biomarker was constructed in form of concentration change ratios or risk ratio(RR),relative risk(HR)and odds ratio(OR)of BCAAs and AAAs to reflect the integrated change information of amino acids.Results:The selected 20 studies contained 14942 healthy individuals and 3615 T2DM patients.The levels of BCAAs,phenylalanine and tyrosine both in plasma and serum samples were increased among all T2DM patients compared with those of the healthy control subjects(P<0.00001).However,the mean difference of tryptophan concentration was not statistically significant(P=0.60).The concentration change ratios or HR/RR/OR of BCAAs and AAAs were connected to form integrated biomarker.Conclusion:The integrated biomarker including BCAAs and AAAs could reflect the basic characteristics of T2DM,which has the potential clinical value on comprehensive diagnosis of T2DM.展开更多
We conducted a simultaneous field study of PM_(2.5)-bound particulate polycyclic aromatic hydrocarbons(PAHs)and aromatic acids(AAs)in a polluted city Zhengzhou to explore the concentration,sources and potential conver...We conducted a simultaneous field study of PM_(2.5)-bound particulate polycyclic aromatic hydrocarbons(PAHs)and aromatic acids(AAs)in a polluted city Zhengzhou to explore the concentration,sources and potential conversion pathways between PAHs and AAs in different seasons.The average concentrations of PM_(2.5),28PAHs and 8AAs during the sampling period were 77μg/m^(3),75 ng/m^(3),and 283 ng/m^(3),respectively.The concentration of both28PAHs and 8AAs were highest in winter and lowest in summer with ratios of 6.3 and 2.3,respectively.PAHs with 5-7 rings were the main components of PAHs(52%),followed by 4rings PAHs(30%)and 2-3 rings PAHs(18%).According to the source appointment results obtained by positive matrix factorization,the main sources of PAHs were combustion and vehicle emissions,which account for 37%and 34%,respectively.8AAs were divided into three groups,including four benzene dicarboxylic acids(B2CAs),three benzene tricarboxylic acids(B3CAs)and one benzene tetracarboxylic acid(B4CA).And interspecies correlation analysis with PM_(2.5)source markers were used to investigate potential sources.Phthalic acid(o-Ph)was the most abundant specie of 8AAs(157 ng/m^(3),55%of 8AAs),which was well correlated with sulfate.Meanwhile,B3CAs and B4CA were highly correlated with sulfate and weakly correlated with levoglucosan,suggesting that secondary formation was their main source.As logical oxidation products of PAHs,o-Ph and B3CAs showed good correlations with a number of PAHs,indicating possible photochemical oxidation pathway by PAHs.In addition,O_(3),NO_(2),temperature and relative humidity have positive effects on the secondary formation of B3CAs.展开更多
The coking kinetics and reaction-regeneration on Zn/HZSM-5 (Zn/HZ) catalyst in the conversion of methanol to aromatics were investigated. The highest initial benzene, toluene and xylene (BTX) yield of ca. 67.7% wa...The coking kinetics and reaction-regeneration on Zn/HZSM-5 (Zn/HZ) catalyst in the conversion of methanol to aromatics were investigated. The highest initial benzene, toluene and xylene (BTX) yield of ca. 67.7% was obtained on fresh Zn/HZ catalyst, which showed the worst catalytic stability. The cycle of reaction-regeneration significantly modified the texture and acidity of Zn/HZ catalyst, which in turn affected its catalytic performance and coking behavior in methanol conversion to BTX. The residual carbon located on the surface of Zn/HZ catalyst led to the decrease of acid sites and the change on the acid sites distribution, which played an important roles on its activity and deactivation. It was found that the high B/L ratio and the low total acid sites concentration of the Zn/HZ catalyst favored to the high BTX yield and good catalytic stability in methanol conversion.展开更多
The stability of organic radicals in ambient condition is important for their practical application.During the development of organic radical chemistry,the electron-withdrawing and steric hindrance groups are usually ...The stability of organic radicals in ambient condition is important for their practical application.During the development of organic radical chemistry,the electron-withdrawing and steric hindrance groups are usually introduced to improve the stability of radicals via reducing the reactivity of radicals with oxygen in air.Herein,the electron-withdrawing carbonyl groups are introduced to construct a planar aromatic oxalic acid radical(IDF-Og)with two-dimensional electron spin pan structure.Interestingly,IDF-Og exhibited a low optical bandgap of 0.91 eV in film,however,the multiple quinone resonance structures between electron-withdrawing ketone and phenol radicals contribute to the high stability of open-shell radical IDF-Og without protection of large steric hindrance groups.Under the irradiation of 808 nm(1.2 W.cm^(-2)),IDF-Og reaches 147 c in powder state.This work provides an efficient synthesis route for the open-shell electron spin pan system,which is different from the famous fullerene,carbon nanotube and graphene.The electron spin pan can be extended to spin tube or spin sphere system based on the design strategy of aromatic inorganic acid radicals in future.展开更多
The oxidative pentose phosphate(OPP)pathway provides metabolic intermediates for the shikimate pathway and directs carbon flow to the biosynthesis of aromatic amino acids(AAAs),which serve as basic protein building bl...The oxidative pentose phosphate(OPP)pathway provides metabolic intermediates for the shikimate pathway and directs carbon flow to the biosynthesis of aromatic amino acids(AAAs),which serve as basic protein building blocks and precursors of numerous metabolites essential for plant growth.However,genetic evidence linking the two pathways is largely unclear.In this study,we identified 6-phosphogluconate dehydrogenase 2(PGD2),the rate-limiting enzyme of the cytosolic OPP pathway,through suppressor screening of arogenate dehydrogenase 2(adh2)in Arabidopsis.Our data indicated that a single amino acid substitution at position 63(glutamic acid to lysine)of PGD2 enhanced its enzyme activity by facilitating the dissociation of products from the active site of PGD2,thus increasing the accumulation of AAAs and partially restoring the defective phenotype of adh2.Phylogenetic analysis indicated that the point mutation occurred in a well-conserved amino acid residue.Plants with different amino acids at this conserved site of PGDs confer diverse catalytic activities,thus exhibiting distinct AAAs producing capability.These findings uncover the genetic link between the OPP pathway and AAAs biosynthesis through PGD2.The gain-of-function point mutation of PGD2 identified here could be considered as a potential engineering target to alter the metabolic flux for the production of AAAs and downstream compounds.展开更多
Introduction of aromatic acid derivatives(AADs)into zwitterionic surfactants is an efficient method to prepare wormlike micelles with pH-controllable viscosity;however,the coincident molecular origin of AAD/zwitterion...Introduction of aromatic acid derivatives(AADs)into zwitterionic surfactants is an efficient method to prepare wormlike micelles with pH-controllable viscosity;however,the coincident molecular origin of AAD/zwitterionic surfactant binary mixtures remains unclear.Herein,the self-assembly of hydroxyl derivatives of benzoic acid(BA)and cetyldimethyl betaine(BS-16)mixtures in water was systematically assessed,and various factors,such as the molecular structure,molar ratio of AAD and BS-16,and solution pH,were investigated.The structure-property relationship of AAD/BS-16 binary mixtures was established,which provided the molecular origin for the effect of AAD on micellar microstructures and the pH-induced morphological transitions.The ortho-substituted hydroxyl moiety in the BA molecule facilitated the formation of larger wormlike micelles,whereas the effect of the meta-substituted moiety was less significant.The para-substituted hydroxyl moiety in BA did not favor micellar growth.This moiety exhibited similar characteristics to the increasing hydroxyl moiety number in the AAD molecules or solution pH where the negative effects of steric hindrance and electrostatic interactions of molecules in micelles aredominant.展开更多
The adsorption behavior ofp-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature. Experimental r...The adsorption behavior ofp-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature. Experimental results indicated that the equilibrium adsorption data of the four polymeric adsorbents fitted well in the Freundlich isotherm. The adsorption capacity of multi-functional polymeric adsorbent NJ-99 was the highest, which might be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of aminobenzoic acid. The adsorption capacity of o-aminobenzoic acid onto any adsorbent was higher than p-aminobenzoic acid. Thermodynamic studies suggested the exothermic, spontaneous physical adsorption process. Adsorption kinetics results showed that the adsorption followed the pseudo-second-order kinetics model and the intraparticle mass transfer process was the rate-controlling step.展开更多
Efficient conversion of lignin to aromatic hydrocarbons via depolymerization and subsequent hydrodeoxygenation is important.Previously,we found that NbOx species played a key role in the activation and cleavage of C-O...Efficient conversion of lignin to aromatic hydrocarbons via depolymerization and subsequent hydrodeoxygenation is important.Previously,we found that NbOx species played a key role in the activation and cleavage of C-O bonds in lignin and its model compounds.In this study,commercial niobic acid(HY-340),niobium phosphate(NbPO-CBMM)and lab-made layered niobium oxide(Nb2O5-Layer)were chosen as supports to study the effect of Brosted and Lewis acids on the activation of C-O bonds in lignin conversion.A variety of Ru-loaded,Nb-based catalysts with different Ru particle sizes were prepared and applied to the conversion of p-cresol.The results show that all the Ru/Nb-based catalysts produce high mole yields of C7-C9 hydrocarbons(82.3%-9.1%).What's more,Ru/Nb2O5-Layer affords the best mole yield of C7-C9 hydrocarbons and selectivity for C7-C9 aromatic hydrocarbons,of up to 99.1% and 88.0%,respectively.Moreover,it was found that Lewis acid sites play important roles in the depolymerization of enzymatic lignin into phenolic monomers and the cleavage of the C-O bond of phenols.Additionally,the electronic state and particle size of Ru are significant factors which influence the selectivity for aromatic hydrocarbons.A partial positive charge on the metallic Ru surface and a smaller Ru particle size are beneficial in improving the selectivity for aromatic hydrocarbons.展开更多
Ratio of Lewis/Brfnsted acid sites (Cl/Cb) on the surface of nano-sized HZSM-5 was successfully manipulated by means of steaming and acid leaching. Significant enhancement of the deactivation durability of nano-sized...Ratio of Lewis/Brfnsted acid sites (Cl/Cb) on the surface of nano-sized HZSM-5 was successfully manipulated by means of steaming and acid leaching. Significant enhancement of the deactivation durability of nano-sized HZSM-5 in the aromatization of fluid catalytic cracking (FCC) gasoline olefins seems to be closely related to the increase of Lewis/Brfnsted acid sites ratio.展开更多
基金Supported by the Open Project Grant for Clinical Medical Center of Yunnan Province,No.2019LCZXKF-NM03Medical Leader Training Grant,No.L-201624and Yunnan Province Ten Thousand Talents:“Medical Expert”grant,No.YNWR-MY-2019-020.
文摘BACKGROUND The lack of specific predictors for type-2 diabetes mellitus(T2DM)severely impacts early intervention/prevention efforts.Elevated branched-chain amino acids(BCAAs:Isoleucine,leucine,valine)and aromatic amino acids(AAAs:Tyrosine,tryptophan,phenylalanine)show high sensitivity and specificity in predicting diabetes in animals and predict T2DM 10-19 years before T2DM onset in clinical studies.However,improvement is needed to support its clinical utility.AIM To evaluate the effects of body mass index(BMI)and sex on BCAAs/AAAs in new-onset T2DM individuals with varying body weight.METHODS Ninety-seven new-onset T2DM patients(<12 mo)differing in BMI[normal weight(NW),n=33,BMI=22.23±1.60;overweight,n=42,BMI=25.9±1.07;obesity(OB),n=22,BMI=31.23±2.31]from the First People’s Hospital of Yunnan Province,Kunming,China,were studied.One-way and 2-way ANOVAs were conducted to determine the effects of BMI and sex on BCAAs/AAAs.RESULTS Fasting serum AAAs,BCAAs,glutamate,and alanine were greater and high-density lipoprotein(HDL)was lower(P<0.05,each)in OB-T2DM patients than in NW-T2DM patients,especially in male OB-T2DM patients.Arginine,histidine,leucine,methionine,and lysine were greater in male patients than in female patients.Moreover,histidine,alanine,glutamate,lysine,valine,methionine,leucine,isoleucine,tyrosine,phenylalanine,and tryptophan were significantly correlated with abdominal adiposity,body weight and BMI,whereas isoleucine,leucine and phenylalanine were negatively correlated with HDL.CONCLUSION Heterogeneously elevated amino acids,especially BCAAs/AAAs,across new-onset T2DM patients in differing BMI categories revealed a potentially skewed prediction of T2DM development.The higher BCAA/AAA levels in obese T2DM patients would support T2DM prediction in obese individuals,whereas the lower levels of BCAAs/AAAs in NW-T2DM individuals may underestimate T2DM risk in NW individuals.This potentially skewed T2DM prediction should be considered when BCAAs/AAAs are to be used as the T2DM predictor.
基金financially supported by the National Natural Science Foundation of China (21276041)the Program for New Century Excellent Talents in University of Ministry of Education (NCET-12-0079)+1 种基金the Natural Science Foundation of Liaoning Province (2015020200)the Fundamental Research Funds for the Central Universities (DUT15LK41)~~
文摘The textural features and acidic properties of sulfated mesoporous lanthana‐zirconia solid acids (SO42?/meso‐La0.1Zr0.9Oδ) were efficiently tuned by modifying the conditions used to prepare the meso‐La0.1Zr0.9Oδcomposites, such as the molar ratio of the template to La and Zr metal ions (Nt/m), molar ratio of ammonia to La and Zr metal ions (Na/m), hydrothermal temperature (Thydro), and hy‐drothermal time (thydro). The effect of the textural features and acidic properties on the catalytic performance of solid acid catalysts for alkenylation of p‐xylene with phenylacetylene was investi‐gated. Various characterization techniques such as N2 physisorption, X‐ray diffraction, NH3 temper‐ature‐programmed desorption, and thermogravimetric analysis were employed to reveal the rela‐tionship between the nature of catalyst and its catalytic performance. It was found that the catalytic performance significantly depended on the textural features and acidic properties, which were strongly affected by preparation conditions of the meso‐La0.1Zr0.9Oδcomposite. Appropriate acidic sites and high accessibility were required to obtain satisfactory catalytic reactions for this reaction. It was also found that the average crystallite size of t‐ZrO2 affected by the preparation conditions had significant influence on the ultrastrong acidic sites of the catalysts. The optimized SO42?/meso‐La0.1Zr0.9Oδcatalyst exhibited much superior catalytic activity and coke‐resistant stabil‐ity. Moreover, the developed SO42?/meso‐La0.1Zr0.9Oδcatalyst demonstrated excellent catalytic per‐formance for alkenylation of diverse aromatics with phenylacetylene to their correspondingα‐arylstyrenes. Combining the previously established complete regeneration of used catalysts by a facile calcination process with the improved catalytic properties, the developed SO42?/meso‐La0.1Zr0.9Oδ solid acid could be a potential catalyst for industrial production ofα‐arylstyrenes through clean and atom efficient solid‐acid‐mediated Friedel‐Crafts alkenylation of diverse aromatics with phenylacetylene.
文摘The condensation of aromatic aldehydes with acidic methylene compounds such as malononitrile, methyl cyanoacetate, cyanoacetamide, 5,5-dimethyl-1,3-cyclohexanedione, bartbituric acid and 2-thiobarbituric acid proceeded very efficiently in water in the presence of triethylbenzylammonium chloride (TEBA) and the products were isolated simply by filtration.
文摘Seven ternary Eu (m) complexes were synthesized with aromatic carboxylic acid (benzoic acid, phenylacetic acid, phenylpropionic acid and cinnamic acid) as the first ligand and 1,10-phenanthro- line or 2,2'-dipyridyl as the second ligand. The ternary Eu( Ⅲ ) complexes were characterized by elemental analysis, IR and TG-DTG methods. In these complexes, the Eu (Ⅲ) ions are bonded to the oxygen atoms of carboxylate and the nitrogen atoms of neutral ligands. Four complexes whose second ligand is 1,10- phenanthrolin have fine thermal stability. Excitation and luminescence spectra of the tide complexes reveal that the fluorescence of the complexes in which 1,10- phenanthrolin as the second ligand are more intensive than those complexes in which 2, 2'-dipyridyl as the second ligand. The order of the strongest emission peak of seven ternary complexes is: Eu(β-PPA)3phen 〉 Eu(BA)3phen 〉 Eu(PLA)3phen 〉 Eu(BA)3bipy 〉 Eu ( PEA)3bipy 〉 Eu ( CA )3phen · H2O 〉 Eu ( CA )3bipy (BA : benzoic ; PEA : phenylacetic ; β-PPA :
文摘The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy, and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.
文摘The electrochemical-voltammetry behavior of vanillin, heliotropin, anisaldehyde on the surface of Pt, Au electrodes in acid solution has been studied by means of the electrochemical cyclic voltammetry method. It was found that the electrochemical processes of them are irreversible on both Pt and Au electrodes. The electrochemical activity of vanillin is stronger than heliotropin's and heliotropin's is stronger than anisaldehyde's on Pt electrode. While the electrochemical activity of anisaldehyde is stronger than heliotropin's and vanillin's is the weakest on Au. The results indicate that when they are used as additives for electroplating, they must be consumptive, and it will improve the leveling ability of plating solution and brightness of the deposition layer.
基金Supported by the Project of Analysis and Detection of Zhejiang Province in 2009 (No. 2009F7044)
文摘A method has been developed for separation of 20 kinds of aromatic carboxylic acid using anion-exchange chromatography. A Dionex IonPac AS9-HC guard column (250mm×2mm) was used with a 9mmol/L sodium carbonate solution containing 50% (v/v) acetonitrile as eluent. A set of retention time data has been obtained using a conductivity detector DS6. Furthermore, geometrical optimization and electrostatic potential calculation of 20 kinds of aromatic carboxylic acid have been performed at the HF/6-31G* level of theory. A number of statistically-based parameters derived from molecular surface electrostatic potential have been obtained. Linear relationship between retention time and structural parameters has been established by multiple regression method. The result shows that parameters derived from electrostatic potential Vs +, Vs -, П together with the dipole moment μ can be well used to express the quantitative structure-retention time of this kind of aromatic carboxylic acid. Good predictive capability has also been demonstrated. The result has provided a framework which further proves the general applicability of this electrostatic potential parameter set to a great extent,and with which the ion chromatographic adsorption mechanism can be investigated.
文摘This current study aims at determining the profile and contents of degradation compounds produced during the interaction between the frying oils and tuna fish involved in the cooking of “Garba”, a street food largely consumed in Côte d’Ivoire. For this purpose, the peroxide index and the neoformed compounds, especially trans fatty acids, acrylamid, polycyclic aromatic hydrocarbons were determined. This trial was carried out on 90 samples of frying oils and fried tuna fish collected from restaurant owners of “Garba” food in three locations in Abidjan. The samples were divided into three groups (G1, G2, and G3) according to the similarity of the practices adopted by the restorers. The results show that the peroxide values (14.95;15.01 and 11.97 meqO2/kg) of the oils respectively for G2, G3, and G1 are higher than the values fixed by the Codex Alimentarius. The trans fatty acid contents of the frying oils were 56.80%;61.01% and 55.18% respectively for G3, G2 and G1. The average acrylamide content of fried Tuna (69.43 μg/kg) is higher than the value recorded in the cooking oil (19.99 μg/kg). The average contents of the eleven HAPs determined in the oils are higher than those of the Tuna. The Benzo (a) pyrene contents of both matrices are lower than the EU standard 1881/2011 except for the G2 oil (2.66 μg/kg). Increased consumption of “Garba” may pose health risks to consumers as practices of frying Tuna generate compounds that are harmful to human health.
基金supported by the Lundbeck Foundationthe Danish Multiple Sclerosis Foundationthe Danish Medical Research Council
文摘Monoamine neurotransmitters include catecholamines and indoleamines. The most common catecholamines are do- pamine (DA), noradrenaline (NA) and adrenaline, which are produced from phenylalanine and tyrosine; whereas the most common indoleamine is serotonin (5-hydroxytrypta mine, 5-HT), which is produced from 5-hydroxytryptophan (5-HTP).
基金This work is supported by Hubei special fund for agricultural science and technology innovation(2018skjcx01)the Engineering Research Center of Ecology and Agricultural Use ofWetland,Ministry of Education(KFT201904).
文摘The improvement of grain quality in aromatic rice is very important for farmer to increase their income.Present study was conducted with a two-year field experiment and three aromatic rice cultivars in order to study the effects of exogenousα-ketoglutaric acid on yield formation,grain quality characters and the biosynthesis of 2-acetyl-1-pyrroline(2-AP,key component of aromatic rice’s fragrance)in aromatic rice.At heading stage,0.50 mmol L^(-1)(T1)and 1.00 mmol L^(-1)(T2)α-ketoglutaric acid solutions were overhead sprinkle to aromatic rice plants,respectively while the treatment which was overhead sprinkled with distilled water was set as control(CK).The results showed that 17.34%-33.04%and 21.39%-34.74%higher grain 2-AP contents were recorded in T1 and T2 treatments,respectively.Compared with CK,T1 and T2 treatments significantly reduced the transcript level of gene BADH2 which is related to the 2-AP biosynthesis in aromatic rice.3.86%-7.51%higher grain protein contents and 1.15%-3.37%higher head rice rates were also recorded inα-ketoglutaric acid treatments than CK.Moreover,T1 and T2 treatments remarkably decreased the chalky rice rate,chalkiness and grain amylose content.However,there was no remarkable difference in grain yield and related trails(effective panicle number,grain number per panicle,seed-setting rate and 1000-grain weight)among CK,T1 and T2 treatments.In conclusion,application of exogenousα-ketoglutaric acid enhanced 2-AP biosynthesis and improved grain quality of aromatic rice.
文摘Action of bromine in concentrated nitric acid allows carrying out mono- and polybromination of moderately deactivated aromatic compounds. 4-Chloronitrobenzene and isophthalic acid turnes into 3-bromo-4-chloronitrobenzene and 5-bromoisophthalic acid at reaction with bromine in concentrated nitric acid at 20°C whereas in absence of bromine in the same conditions 4-chloro-1, 3-dinitrobenzene and 5-nitroisophthalic acid are formed accordingly. Presence of bromine in concentrated nitric acid changes nitrating capacity to brominating one. Terephthalic acid and phthalic anhydride at heating with bromine in concentrated nitric acid can be transformed to appropriating tetrabromo substituted compounds.
基金supported by the National Natural Science Foundation of China(grant number 81773891)the National Great New Drugs Development Project of China(grant number 2017ZX09301-040)the Beijing Municipal Science and Technology Commission(grant number XMLX201704,2018-2-2242,7194280).
文摘Background:As type 2 diabetes mellitus(T2DM)biomarkers,branched-chain amino acids(BCAAs:valine,leucine and isoleucine)and aromatic amino acids(AAAs:phenylalanine,tryptophan and tyrosine)may be correlated with the occurrence and development of T2DM.However,there is still no consensus on the disperse and isolated biomarkers of T2DM.Purpose:To explore the correlation between amino acids and T2DM based on integrated biomarker approach revealed.Methods:PubMed,Web of Science and CNKI were selected to search the literature published until August 31,2019.The included studies described the association between BCAAs,AAAs and T2DM.Random effect model and fixed effect model were adopted in pooled analysis to determine mean difference and 95 percent confidence interval of metabolites.Integrated biomarker was constructed in form of concentration change ratios or risk ratio(RR),relative risk(HR)and odds ratio(OR)of BCAAs and AAAs to reflect the integrated change information of amino acids.Results:The selected 20 studies contained 14942 healthy individuals and 3615 T2DM patients.The levels of BCAAs,phenylalanine and tyrosine both in plasma and serum samples were increased among all T2DM patients compared with those of the healthy control subjects(P<0.00001).However,the mean difference of tryptophan concentration was not statistically significant(P=0.60).The concentration change ratios or HR/RR/OR of BCAAs and AAAs were connected to form integrated biomarker.Conclusion:The integrated biomarker including BCAAs and AAAs could reflect the basic characteristics of T2DM,which has the potential clinical value on comprehensive diagnosis of T2DM.
基金supported by the Natural Science Foundation of Henan Province(No.232300421395)the National Key Research and Development Program of China(No.2017YFC0212400)。
文摘We conducted a simultaneous field study of PM_(2.5)-bound particulate polycyclic aromatic hydrocarbons(PAHs)and aromatic acids(AAs)in a polluted city Zhengzhou to explore the concentration,sources and potential conversion pathways between PAHs and AAs in different seasons.The average concentrations of PM_(2.5),28PAHs and 8AAs during the sampling period were 77μg/m^(3),75 ng/m^(3),and 283 ng/m^(3),respectively.The concentration of both28PAHs and 8AAs were highest in winter and lowest in summer with ratios of 6.3 and 2.3,respectively.PAHs with 5-7 rings were the main components of PAHs(52%),followed by 4rings PAHs(30%)and 2-3 rings PAHs(18%).According to the source appointment results obtained by positive matrix factorization,the main sources of PAHs were combustion and vehicle emissions,which account for 37%and 34%,respectively.8AAs were divided into three groups,including four benzene dicarboxylic acids(B2CAs),three benzene tricarboxylic acids(B3CAs)and one benzene tetracarboxylic acid(B4CA).And interspecies correlation analysis with PM_(2.5)source markers were used to investigate potential sources.Phthalic acid(o-Ph)was the most abundant specie of 8AAs(157 ng/m^(3),55%of 8AAs),which was well correlated with sulfate.Meanwhile,B3CAs and B4CA were highly correlated with sulfate and weakly correlated with levoglucosan,suggesting that secondary formation was their main source.As logical oxidation products of PAHs,o-Ph and B3CAs showed good correlations with a number of PAHs,indicating possible photochemical oxidation pathway by PAHs.In addition,O_(3),NO_(2),temperature and relative humidity have positive effects on the secondary formation of B3CAs.
基金supported by the National Ministry of Education(NCET-10-878)Shaanxi"13115"Innovation Project(2009ZDKJ-70)Shaanxi Key Innovation Project(2011ZKC4-08)
文摘The coking kinetics and reaction-regeneration on Zn/HZSM-5 (Zn/HZ) catalyst in the conversion of methanol to aromatics were investigated. The highest initial benzene, toluene and xylene (BTX) yield of ca. 67.7% was obtained on fresh Zn/HZ catalyst, which showed the worst catalytic stability. The cycle of reaction-regeneration significantly modified the texture and acidity of Zn/HZ catalyst, which in turn affected its catalytic performance and coking behavior in methanol conversion to BTX. The residual carbon located on the surface of Zn/HZ catalyst led to the decrease of acid sites and the change on the acid sites distribution, which played an important roles on its activity and deactivation. It was found that the high B/L ratio and the low total acid sites concentration of the Zn/HZ catalyst favored to the high BTX yield and good catalytic stability in methanol conversion.
基金supported by the Natural Science Foundation of China(22375065,51973063).
文摘The stability of organic radicals in ambient condition is important for their practical application.During the development of organic radical chemistry,the electron-withdrawing and steric hindrance groups are usually introduced to improve the stability of radicals via reducing the reactivity of radicals with oxygen in air.Herein,the electron-withdrawing carbonyl groups are introduced to construct a planar aromatic oxalic acid radical(IDF-Og)with two-dimensional electron spin pan structure.Interestingly,IDF-Og exhibited a low optical bandgap of 0.91 eV in film,however,the multiple quinone resonance structures between electron-withdrawing ketone and phenol radicals contribute to the high stability of open-shell radical IDF-Og without protection of large steric hindrance groups.Under the irradiation of 808 nm(1.2 W.cm^(-2)),IDF-Og reaches 147 c in powder state.This work provides an efficient synthesis route for the open-shell electron spin pan system,which is different from the famous fullerene,carbon nanotube and graphene.The electron spin pan can be extended to spin tube or spin sphere system based on the design strategy of aromatic inorganic acid radicals in future.
基金supported by the National Key Research and Development Program of China(2019YFA0903900)the National Natural Science Foundation of China(32300233)+1 种基金Guangdong Provincial Key Laboratory of Synthetic Genomics(2023B1212060054)Shenzhen Key Laboratory of Synthetic Genomics(ZDSYS201802061806209).
文摘The oxidative pentose phosphate(OPP)pathway provides metabolic intermediates for the shikimate pathway and directs carbon flow to the biosynthesis of aromatic amino acids(AAAs),which serve as basic protein building blocks and precursors of numerous metabolites essential for plant growth.However,genetic evidence linking the two pathways is largely unclear.In this study,we identified 6-phosphogluconate dehydrogenase 2(PGD2),the rate-limiting enzyme of the cytosolic OPP pathway,through suppressor screening of arogenate dehydrogenase 2(adh2)in Arabidopsis.Our data indicated that a single amino acid substitution at position 63(glutamic acid to lysine)of PGD2 enhanced its enzyme activity by facilitating the dissociation of products from the active site of PGD2,thus increasing the accumulation of AAAs and partially restoring the defective phenotype of adh2.Phylogenetic analysis indicated that the point mutation occurred in a well-conserved amino acid residue.Plants with different amino acids at this conserved site of PGDs confer diverse catalytic activities,thus exhibiting distinct AAAs producing capability.These findings uncover the genetic link between the OPP pathway and AAAs biosynthesis through PGD2.The gain-of-function point mutation of PGD2 identified here could be considered as a potential engineering target to alter the metabolic flux for the production of AAAs and downstream compounds.
基金support from the National Natural Science Foundation of China[NSFC 22072109,22372125].
文摘Introduction of aromatic acid derivatives(AADs)into zwitterionic surfactants is an efficient method to prepare wormlike micelles with pH-controllable viscosity;however,the coincident molecular origin of AAD/zwitterionic surfactant binary mixtures remains unclear.Herein,the self-assembly of hydroxyl derivatives of benzoic acid(BA)and cetyldimethyl betaine(BS-16)mixtures in water was systematically assessed,and various factors,such as the molecular structure,molar ratio of AAD and BS-16,and solution pH,were investigated.The structure-property relationship of AAD/BS-16 binary mixtures was established,which provided the molecular origin for the effect of AAD on micellar microstructures and the pH-induced morphological transitions.The ortho-substituted hydroxyl moiety in the BA molecule facilitated the formation of larger wormlike micelles,whereas the effect of the meta-substituted moiety was less significant.The para-substituted hydroxyl moiety in BA did not favor micellar growth.This moiety exhibited similar characteristics to the increasing hydroxyl moiety number in the AAD molecules or solution pH where the negative effects of steric hindrance and electrostatic interactions of molecules in micelles aredominant.
基金Project supported by the National Key Technology Research and Development Program of China(No.2006BAC02A15)Opening Foundation of Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection of China(No.JLCBE05006)the Qinglan Project of Jiangsu Province
文摘The adsorption behavior ofp-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature. Experimental results indicated that the equilibrium adsorption data of the four polymeric adsorbents fitted well in the Freundlich isotherm. The adsorption capacity of multi-functional polymeric adsorbent NJ-99 was the highest, which might be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of aminobenzoic acid. The adsorption capacity of o-aminobenzoic acid onto any adsorbent was higher than p-aminobenzoic acid. Thermodynamic studies suggested the exothermic, spontaneous physical adsorption process. Adsorption kinetics results showed that the adsorption followed the pseudo-second-order kinetics model and the intraparticle mass transfer process was the rate-controlling step.
基金supported by the National Natural Science Foundation of China(21832002,21872050,21808063)the Natural Science Foundation of Shanghai(18ZR1408500)~~
文摘Efficient conversion of lignin to aromatic hydrocarbons via depolymerization and subsequent hydrodeoxygenation is important.Previously,we found that NbOx species played a key role in the activation and cleavage of C-O bonds in lignin and its model compounds.In this study,commercial niobic acid(HY-340),niobium phosphate(NbPO-CBMM)and lab-made layered niobium oxide(Nb2O5-Layer)were chosen as supports to study the effect of Brosted and Lewis acids on the activation of C-O bonds in lignin conversion.A variety of Ru-loaded,Nb-based catalysts with different Ru particle sizes were prepared and applied to the conversion of p-cresol.The results show that all the Ru/Nb-based catalysts produce high mole yields of C7-C9 hydrocarbons(82.3%-9.1%).What's more,Ru/Nb2O5-Layer affords the best mole yield of C7-C9 hydrocarbons and selectivity for C7-C9 aromatic hydrocarbons,of up to 99.1% and 88.0%,respectively.Moreover,it was found that Lewis acid sites play important roles in the depolymerization of enzymatic lignin into phenolic monomers and the cleavage of the C-O bond of phenols.Additionally,the electronic state and particle size of Ru are significant factors which influence the selectivity for aromatic hydrocarbons.A partial positive charge on the metallic Ru surface and a smaller Ru particle size are beneficial in improving the selectivity for aromatic hydrocarbons.
文摘Ratio of Lewis/Brfnsted acid sites (Cl/Cb) on the surface of nano-sized HZSM-5 was successfully manipulated by means of steaming and acid leaching. Significant enhancement of the deactivation durability of nano-sized HZSM-5 in the aromatization of fluid catalytic cracking (FCC) gasoline olefins seems to be closely related to the increase of Lewis/Brfnsted acid sites ratio.