To deepen the understanding in the effect of potassium lactate on the sensory quality and safety of Rugao ham,sensory attributes,physicochemical parameters,total volatile basic nitrogen(TVBN),microorganism community a...To deepen the understanding in the effect of potassium lactate on the sensory quality and safety of Rugao ham,sensory attributes,physicochemical parameters,total volatile basic nitrogen(TVBN),microorganism community and biogenic amines of Rugao ham manufactured with different potassium lactate levels(0%,0.5%,1%,2%)were investigated;the relationship between microbial community and the formation of TVBN and biogenic amines was further evaluated.With the increase of potassium lactate from 0%to 2%,the increased sensory scores and the decreased total aerobic bacterial count and TVBN were observed;the abundance of Staphylococcus increased,while the content of Halomonas decreased.LDA effect size(LEf Se)and correlations analysis showed that Staphylococcus equorum and Lactobacillus fermentum could be the key species to improve sensory scores and decrease biogenic amines and TVBN.Metabolic pathway analysis further showed that amino acids metabolism and nitrogen metabolism were mainly involved in decreasing TVBN and biogenic amines in the treatment of 2%potassium lactate.展开更多
Amine transaminases(ATAs)catalyze the asymmetric amination of prochiral ketones or aldehydes to their corresponding chiral amines.However,the trade-off between activity and stability in enzyme engineering represents a...Amine transaminases(ATAs)catalyze the asymmetric amination of prochiral ketones or aldehydes to their corresponding chiral amines.However,the trade-off between activity and stability in enzyme engineering represents a major obstacle to the practical application of ATAs.Overcoming this trade-off is important for developing robustly engineered enzymes and a universal approach for ATAs.Herein,we modified the binding pocket of co-ATA from Aspergillus terreus(AtATA)to identify the key amino acid residues controlling the activity and stability of AtATA toward 1-acetonaphthone.We discovered a structural switch comprising four key amino acid sites(R128,V149,L182,and L187),as well as the"best"mutant(AtATAD224K/V149A/L182 F/L187F;termed M4).Compared to the parent enzyme AtATAD224K(AtATAPa),M4 increased the catalytic efficiency(k_(cat)/K_(m)^(1-acetonaphthone),where kcatis the constant of catalytic activities and is 10.1 min^(-1),K_(m)^(1-acetonaphthoneis) Michaelis-Menten constant and is 1.7 mmol·L^(-1))and half-life(t1/2)by 59-fold to 5.9 L·min^(-1)·mmol-1and by 1.6-fold to 46.9 min,respectively.Moreover,using M4 as the biocatalyst,we converted a 20 mmol·L^(-1)aliquot of 1-acetonaphthone in a 50 mL scaled-up system to the desired product,(R)-(+)-1(1-naphthyl)ethylamine((R)-NEA),with 78%yield and high enantiomeric purity(R>99.5%)within 10 h.M4 also displayed significantly enhanced activity toward various 1-acetonaphthone analogs.The related structural properties derived by analyzing structure and sequence information of robust ATAs illustrated their enhanced activity and thermostability.Strengthening of intramolecular interactions and expansion of the angle between the substratebinding pocket and the pyridoxal 5’-phosphate(PLP)-binding pocket contributed to synchronous enhancement of ATA thermostability and activity.Moreover,this pocket engineering strategy successfully transferred enhanced activity and thermostability to three other ATAs,which exhibited 8%-22%sequence similarity with AtATA.This research has important implications for overcoming the trade-off between ATA activity and thermostability.展开更多
Polyimide(PI) is an organic polymer material with good stability and diverse sources that has attracted widespread attention in the field of photocatalysis. In this study, a series of PI photocatalysts were synthesize...Polyimide(PI) is an organic polymer material with good stability and diverse sources that has attracted widespread attention in the field of photocatalysis. In this study, a series of PI photocatalysts were synthesized by a thermal polymerization approach using pyromellitic dianhydride(PMDA) and various diamine monomers(melamine(MA), 4,4′-oxydianiline, and melem) as the precursors as well as different heating rates. The effects of the diamine precursor and heating rate on the structure, composition, morphology, and optical properties of the as-prepared PI materials were systematically investigated by various characterization techniques. The selective photo-oxidation of benzylamine was used as a model reaction to evaluate the photocatalytic activities of the resulting PI samples for the oxidation of amines to imines. The results revealed that the PI sample prepared using MA and PMDA as the precursors and a heating rate of 7 ℃/min(MA-PI-7) exhibited the best catalytic performance, with 98% benzylamine conversion and 98% selectivity for N-benzylidene benzylamine after 4 h of irradiation. Several benzylamine derivatives and heterocyclic amines also underwent the photo-oxidation reaction over the MA-PI-7 catalyst to afford the corresponding imines with good activity. In addition, MA-PI-7 exhibited good stability over four successive photocatalytic cycles.展开更多
A mesoporous UiO-66-NH_(2) aerogel is prepared via a straightforward sol-gel method without using any binders or mechanical pressures, in which the amine groups are directly introduced into the matrix by using 2-amino...A mesoporous UiO-66-NH_(2) aerogel is prepared via a straightforward sol-gel method without using any binders or mechanical pressures, in which the amine groups are directly introduced into the matrix by using 2-aminoterephthalic acid. The novel UiO-66-NH_(2) aerogel also exhibits high specific surface area and mesopore-dominated structure, implying its highly potential use in CO_(2) adsorption. For ulteriorly investigating the effect of amine loading on the CO_(2) adsorption ability, a series of UiO-66-NH_(2) aerogel with different amino content is fabricated by changing the ligand/metal molar ratio. When the molar ratio is 1.45, the CO_(2) adsorption capacity reaches the optimum value of 2.13 mmol·g^(-1) at 25 ℃ and 0.1 MPa, which is 12.2% higher than that of pure UiO-66 aerogel. Additionally, UiO-66-NH_(2)-1.45 aerogel also has noticeable CO_(2) selectivity against N_(2) and CH_(4) as well as good regeneration stability. Such results imply that it has good application prospect in the field of CO_(2) adsorption, and also contains the potential to be applied in catalysis, separation and other fields.展开更多
Numerous small-molecule amines(SMAs)play critical roles in maintaining bone homeostasis and promoting bone regeneration regardless of whether they are applied as drugs or biomaterials.On the one hand,SMAs promote bone...Numerous small-molecule amines(SMAs)play critical roles in maintaining bone homeostasis and promoting bone regeneration regardless of whether they are applied as drugs or biomaterials.On the one hand,SMAs promote bone formation or inhibit bone resorption through the regulation of key molecular signaling pathways in osteoblasts/osteoclasts;on the other hand,owing to their alkaline properties as well as their antioxidant and anti-inflammatory features,most SMAs create a favorable microenvironment for bone homeostasis.However,due to a lack of information on their structure/bioactivity and underlying mechanisms of action,certain SMAs cannot be developed into drugs or biomaterials for bone disease treatment.In this review,we thoroughly summarize the current understanding of SMA effects on bone homeostasis,including descriptions of their classifications,biochemical features,recent research advances in bone biology and related regulatory mechanisms in bone regeneration.In addition,we discuss the challenges and prospects of SMA translational research.展开更多
Trace amines(TAs)are metabolically related to catecholamine and associated with cancer and neurological disorders.Comprehensive measurement of TAs is essential for understanding pathological processes and providing pr...Trace amines(TAs)are metabolically related to catecholamine and associated with cancer and neurological disorders.Comprehensive measurement of TAs is essential for understanding pathological processes and providing proper drug intervention.However,the trace amounts and chemical instability of TAs challenge quantification.Here,diisopropyl phosphite coupled with chip two-dimensional(2D)liquid chromatography tandem triple-quadrupole mass spectrometry(LC-QQQ/MS)was developed to simultaneously determine TAs and associated metabolites.The results showed that the sensitivities of TAs increased up to 5520 times compared with those using nonderivatized LC-QQQ/MS.This sensitive method was utilized to investigate their alterations in hepatoma cells after treatment with sorafenib.The significantly altered TAs and associated metabolites suggested that phenylalanine and tyrosine metabolic pathways were related to sorafenib treatment in Hep3B cells.This sensitive method has great potential to elucidate the mechanism and diagnose diseases considering that an increasing number of physiological functions of TAs have been discovered in recent decades.展开更多
Meat products are an important part in our daily diet,providing valuable nutrients for the human body.However,heating processes cause the meat to become more appetizing with changes in texture,appearance,flavor,and ch...Meat products are an important part in our daily diet,providing valuable nutrients for the human body.However,heating processes cause the meat to become more appetizing with changes in texture,appearance,flavor,and chemical properties by the altering of protein structure and other ingredients.As one kind of cooking-induced contaminants,heterocyclic aromatic amines(HAAs)are widely present in protein aceous food products with strong carcinogenic and mutagenic properties.In order to promote the safety of traditional meat products,this review focused on the formation,metabolism,biological monitoring and inhibitory mechanism of HAA.An overview of the formation pathways,hazards,and control methods of HAAs during food processing in recent years was studied,aiming to provide some valuable information for exploring effective methods to inhibit the production of associated hazards during food processing.Systematic selection of different types of flavonoids to explore their effects on the formation of HAAs in an actual barbecue system can provide theoretical reference for effectively controlling the formation of HAAs and reducing their harm to human health.展开更多
Polyamine-based scavenger resins containing 2, 3 and 4 nitrogen atoms have been prepared and their comparative efficacy to scavenge appropriate electrophilic chemicals (acids, acid chlorides, isocyanates and aldehydes...Polyamine-based scavenger resins containing 2, 3 and 4 nitrogen atoms have been prepared and their comparative efficacy to scavenge appropriate electrophilic chemicals (acids, acid chlorides, isocyanates and aldehydes) from solutions has been studied. As expected, the scavenging efficiency is directly proportional to the number of nucleophic nitrogens present on the resin. The results have been compared with the performance of the popular scavenger resin, namely, tris(2-aminoethyl)amine resin, to conclude that the low-cost polyamine resins now prepared can be conveniently used as effectively as the expensive commercial product.展开更多
Differential heat of absorption of CO_2 in aqueous solutions of N,N-diethylethanolamine(DEEA) and activated DEEA solutions up to a total concentration of 2 mol·L^(-1) was measured as a function of CO_2 loading at...Differential heat of absorption of CO_2 in aqueous solutions of N,N-diethylethanolamine(DEEA) and activated DEEA solutions up to a total concentration of 2 mol·L^(-1) was measured as a function of CO_2 loading at 313.15 K using a reaction calorimeter. In order to analyze the performance of N-methyl-1,3-propanediamine(MAPA)as an activator, DEEA blended solutions containing 0.05, 0.1 and 0.2 mol·L^(-1) MAPA were studied. The heat of CO_2 absorption in single DEEA solutions was unaffected by changing the DEEA concentration in the range of(0.5–2) mol·L^(-1). On the other hand, increasing the concentration of MAPA in aqueous amine mixtures of(DEEA + MAPA) raised the heat of absorption.展开更多
Selective reductive amination of carbonyl compounds with high activity is very essential for the chemical and pharmaceutical industry,but scarcely successful paradigm was reported via efficient photocatalytic reaction...Selective reductive amination of carbonyl compounds with high activity is very essential for the chemical and pharmaceutical industry,but scarcely successful paradigm was reported via efficient photocatalytic reactions.Herein,the ultrasmall Ru nanoclusters(~0.9 nm)were successfully fabricated over P25 support with positive charged Ru^(δ+)species at the interface.A new route was developed to achieve the furfural(FAL)to furfurylamine(FAM)by coupling the light-driven reductive amination and hydrogen transfer of ethanol over this type catalyst.Strikingly,the photocatalytic activity and selectivity are strongly dependent on the particle size and electronic structure of Ruthenium.The Ru^(δ+)species at the interface promote the formation of active imine intermediates;moreover,the Ru nanoclusters facilitate the separation efficiency of electrons and holes as well as accelerate the further hydrogenation of imine intermediates to product primary amines.In contrast Ru particles in larger nanometer size facilitate the formation of the furfuryl alcohol and excessive hydrogenation products.In addition,the coupling byproducts can be effectively inhibited via the construction of sub-nanocluster.This study offers a new path to produce the primary amines from biomass-derived carbonyl compounds over hybrid semiconductor/metal-clusters photocatalyst via light-driven tandem catalytic process.展开更多
Synthesizing nitrogen(N)-containing molecules from biomass derivatives is a new strategy for production of this kind of chemicals.Herein,for the first time we present the synthesis of N-substituted aryl pyrroles via r...Synthesizing nitrogen(N)-containing molecules from biomass derivatives is a new strategy for production of this kind of chemicals.Herein,for the first time we present the synthesis of N-substituted aryl pyrroles via reductive amination/cyclization of levulinic acid(LA)with primary aromatic amines and hydrosilanes(e.g.,PMHS)over Cs F,and a series of N-substituted aryl pyrroles could be obtained in good to excellent yields at 120○C.The mechanism investigation indicates that the reaction proceeds in two steps:the cyclization between amine and LA occurs first to form intermediate 5-methyl-N-alkyl-1,3-dihydro-2H-pyrrolones and their isomeride(B),and then the chemo-and region-selective reduction of intermediates take place to produce the final products.This approach for synthesis of N-substituted aryl pyrroles can be performed under mild and green conditions,which may have promising applications.展开更多
Since the utilization of abundant biomass to develop advanced materials has become an utmost priority in recent years,we developed two sustainable routes(i.e.,the impregnation method and the one-pot synthesis)to prepa...Since the utilization of abundant biomass to develop advanced materials has become an utmost priority in recent years,we developed two sustainable routes(i.e.,the impregnation method and the one-pot synthesis)to prepare the hydrochar-supported catalysts and tested its catalytic performance on the reductive amination.Several techniques,such as TEM,XRD and XPS,were adopted to characterize the structural and catalytic features of samples.Results indicated that the impregnation method favors the formation of outer-sphere surface complexes with porous structure as well as well-distributed metallic nanoparticles,while the one-pot synthesis tends to form the inner-sphere surface complexes with relatively smooth appearance and amorphous metals.This difference explains the better activity of catalysts prepared by the impregnation method which can selectively convert benzaldehyde to benzylamine with an excellent yield of 93.7%under the optimal reaction conditions;in contrast,the catalyst prepared by the one-pot synthesis only exhibits a low selectivity near to zero.Furthermore,the gram-scale test catalyzed by the same catalysts exhibits a similar yield of benzylamine in comparison to its smaller scale,which is comparable to the previously reported heterogeneous noble-based catalysts.More surprisingly,the prepared catalysts can be expediently recycled by a magnetic bar and remain the satisfying catalytic activity after reusing up to five times.In conclusion,these developed catalysts enable the synthesis of functional amines with excellent selectivity and carbon balance,proving cost-effective and sustainable access to the wide application of reductive amination.展开更多
Industrial grade multi-walled carbon nanotubes(IG-MWCNTs) are a low-cost substitute for commercially purified multi-walled carbon nanotubes(P-MWCNTs). In this work, IG-MWCNTs were functionalized with tetraethylenepent...Industrial grade multi-walled carbon nanotubes(IG-MWCNTs) are a low-cost substitute for commercially purified multi-walled carbon nanotubes(P-MWCNTs). In this work, IG-MWCNTs were functionalized with tetraethylenepentamine(TEPA) for CO2capture. The TEPA impregnated IG-MWCNTs were characterized with various experimental methods including N2adsorption/desorption isotherms, elemental analysis, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. Both the adsorption isotherms of IGMWCNTs-n and the isosteric heats of different adsorption capacities were obtained from experiments. TEPA impregnated IG-MWCNTs were also shown to have high CO2adsorption capacity comparable to that of TEPA impregnated P-MWCNTs. The adsorption capacity of IG-MWCNTs based adsorbents was in the range of 2.145 to 3.088 mmol/g, depending on adsorption temperatures. Having the advantages of low-cost and high adsorption capacity, TEPA impregnated IG-MWCNTs seem to be a promising adsorbent for CO2capture from flue gas.展开更多
A testing method for N-nitrosamines and N-nitrosatable substances in rubber teats and soothers was modified. N-Nitrosamines are generally analyzed using either a nitrogen chemiluminescence detector (NCD) or a thermal ...A testing method for N-nitrosamines and N-nitrosatable substances in rubber teats and soothers was modified. N-Nitrosamines are generally analyzed using either a nitrogen chemiluminescence detector (NCD) or a thermal energy analyzer (TEA). However, because few testing laboratories are equipped with these devices, it is difficult to conduct these tests. Therefore, an analysis method for N-nitrosamines using the more widespread gas chromatography-mass spectrometry (GC-MS) method was improved. In addition, EN 12868 was used to prepare the test solutions because of its worldwide use and compliance with EU regulations. Using GC-MS, EN 12868 method targeting ten kinds of N-nitrosamines was modified. The determination limits of the method were 1.0 -1.5 μg/kg for N-nitrosamines and 4 -6 μg/kg for N-nitrosatable substances. Quantification was possible at 1/5 or less and 1/15 or less, respectively, of the regulation values listed in EU Directive 93/11/EEC. In terms of application, there were no problems with the selectivity of the detector. The recoveries were 58% -109% for N-nitrosamines and 59% -102% for N-nitrosatable substances. Screening and verification were possible by measuring the amount of secondary amines in the boiled solution and migration solution.展开更多
Hemocyte counts and phenoloxidase(PO)activity were examined after hemolymph being incubated in dopamine(DA),noradrenaline(NE)and serotonin(5-HT).Results showed that all the three biogenic amines(BAs)had a significant ...Hemocyte counts and phenoloxidase(PO)activity were examined after hemolymph being incubated in dopamine(DA),noradrenaline(NE)and serotonin(5-HT).Results showed that all the three biogenic amines(BAs)had a significant impact on total hemocyte count(THC),differential hemocyte count(DHC),and intracelluar and extracelluar phenoloxidase(PO)activity.Among these Bas,DA had the strongest effect on the above parameters,whereas 5-HT had the least effect.Preincubation with D1 receptor antagonist SCH23390,D2 receptor antagonist Sulpiride and 1:1 admixture of the two could significantly inhibit the effect of DA on these parameters.SCH23390 showed a stronger inhibitory effect than Sulpiride,and the admixture exhibited the strongest effect.These results suggested that the change of hemocyte count and activation of prophenoloxidase(proPO)system in Litopenaeusvan-namei hemocyte can be regulated by BAs,and DA modulates the two parameters via its receptors.展开更多
Biogenic amines are known to have various biological functions such as not only neurotransmitter and cell proliferation but also food poisoning. Bacterially-decomposed amines such as histamine, agmatine, putrescine, c...Biogenic amines are known to have various biological functions such as not only neurotransmitter and cell proliferation but also food poisoning. Bacterially-decomposed amines such as histamine, agmatine, putrescine, cadaverine, spermidine and spermine cause allergic symptoms. We developed simple method for measurement of polyamine as indicator of food decomposition with a fluorometer by using 4-(1-Pyrene)butyric acid N-hydroxysuccinimide ester (PSE). PSE reacts with primary and secondary amino moieties of polyamines and produces the intramolecular excimer fluorescence. Excimer fluorescence with broad peak at around 470 nm was clearly detected in linear type biogenic amines such as putrescine, cadaverine, spermidine and spermine at 10 mM. However neither histamine nor trimethylamine altered the fluorescence. Decomposed sardine and mackerel by improper storage showed stronger intensity than fresh ones. Comparing with OPA-method, PSE method was useful for screening biogenic amines present in food, esp. fish since the analysis was simple after one-step purification procedure. An inexpensive system which can rapidly detect biogenic amines from food is necessary in a medium and small-sized food business. The technique using excimer has potential to realize the high through-put screening system for evaluation of food freshness and is expected to bring the public interests such as food security and safety of consumer.展开更多
Time resolved laser spectroscopy and GC/MS were used to investigate the primary processes and the side reactions occurring in benzophenone and chlorothioxanthone/amine systems used as photoinitiators of radical polyme...Time resolved laser spectroscopy and GC/MS were used to investigate the primary processes and the side reactions occurring in benzophenone and chlorothioxanthone/amine systems used as photoinitiators of radical polymerization. The discrepancy observed between the experimental data and the expected behaviour is accounted for by detrimental chemical reaction involving the ketone triplet state, the ketyl radical and the amine-derived radical.展开更多
The syntheses of N-Methyl-14C benzyl amine and N-Methyl-14C benzyl nitrosamine are reported. Specific activities were approximately 920 MBq/mmol. Chemical and radiochemical purity checked by HPLC were more than 95%.
基金supported by National Natural Science Foundation of China(32022066,32101975)Zhejiang Province Natural Science Foundation(LQ22C200017)+1 种基金China Postdoctoral Foundation(2020M681806,2021T140348)Science and Technology Programs of Ningbo(202003N4130,202002N3067)。
文摘To deepen the understanding in the effect of potassium lactate on the sensory quality and safety of Rugao ham,sensory attributes,physicochemical parameters,total volatile basic nitrogen(TVBN),microorganism community and biogenic amines of Rugao ham manufactured with different potassium lactate levels(0%,0.5%,1%,2%)were investigated;the relationship between microbial community and the formation of TVBN and biogenic amines was further evaluated.With the increase of potassium lactate from 0%to 2%,the increased sensory scores and the decreased total aerobic bacterial count and TVBN were observed;the abundance of Staphylococcus increased,while the content of Halomonas decreased.LDA effect size(LEf Se)and correlations analysis showed that Staphylococcus equorum and Lactobacillus fermentum could be the key species to improve sensory scores and decrease biogenic amines and TVBN.Metabolic pathway analysis further showed that amino acids metabolism and nitrogen metabolism were mainly involved in decreasing TVBN and biogenic amines in the treatment of 2%potassium lactate.
基金National Natural Science Foundation of China(32071268 and 31971372)the Ningbo"Scientific and Technological Innovation 2025"Key Project(2020Z080)for financial support。
文摘Amine transaminases(ATAs)catalyze the asymmetric amination of prochiral ketones or aldehydes to their corresponding chiral amines.However,the trade-off between activity and stability in enzyme engineering represents a major obstacle to the practical application of ATAs.Overcoming this trade-off is important for developing robustly engineered enzymes and a universal approach for ATAs.Herein,we modified the binding pocket of co-ATA from Aspergillus terreus(AtATA)to identify the key amino acid residues controlling the activity and stability of AtATA toward 1-acetonaphthone.We discovered a structural switch comprising four key amino acid sites(R128,V149,L182,and L187),as well as the"best"mutant(AtATAD224K/V149A/L182 F/L187F;termed M4).Compared to the parent enzyme AtATAD224K(AtATAPa),M4 increased the catalytic efficiency(k_(cat)/K_(m)^(1-acetonaphthone),where kcatis the constant of catalytic activities and is 10.1 min^(-1),K_(m)^(1-acetonaphthoneis) Michaelis-Menten constant and is 1.7 mmol·L^(-1))and half-life(t1/2)by 59-fold to 5.9 L·min^(-1)·mmol-1and by 1.6-fold to 46.9 min,respectively.Moreover,using M4 as the biocatalyst,we converted a 20 mmol·L^(-1)aliquot of 1-acetonaphthone in a 50 mL scaled-up system to the desired product,(R)-(+)-1(1-naphthyl)ethylamine((R)-NEA),with 78%yield and high enantiomeric purity(R>99.5%)within 10 h.M4 also displayed significantly enhanced activity toward various 1-acetonaphthone analogs.The related structural properties derived by analyzing structure and sequence information of robust ATAs illustrated their enhanced activity and thermostability.Strengthening of intramolecular interactions and expansion of the angle between the substratebinding pocket and the pyridoxal 5’-phosphate(PLP)-binding pocket contributed to synchronous enhancement of ATA thermostability and activity.Moreover,this pocket engineering strategy successfully transferred enhanced activity and thermostability to three other ATAs,which exhibited 8%-22%sequence similarity with AtATA.This research has important implications for overcoming the trade-off between ATA activity and thermostability.
基金the Opening Project of Key Laboratory of Green Catalysis of Higher Education Institutes of Sichuan(Grant number:LZJ2101)the Fundamental Research Funds of China West Normal University(Grant number:19D038).
文摘Polyimide(PI) is an organic polymer material with good stability and diverse sources that has attracted widespread attention in the field of photocatalysis. In this study, a series of PI photocatalysts were synthesized by a thermal polymerization approach using pyromellitic dianhydride(PMDA) and various diamine monomers(melamine(MA), 4,4′-oxydianiline, and melem) as the precursors as well as different heating rates. The effects of the diamine precursor and heating rate on the structure, composition, morphology, and optical properties of the as-prepared PI materials were systematically investigated by various characterization techniques. The selective photo-oxidation of benzylamine was used as a model reaction to evaluate the photocatalytic activities of the resulting PI samples for the oxidation of amines to imines. The results revealed that the PI sample prepared using MA and PMDA as the precursors and a heating rate of 7 ℃/min(MA-PI-7) exhibited the best catalytic performance, with 98% benzylamine conversion and 98% selectivity for N-benzylidene benzylamine after 4 h of irradiation. Several benzylamine derivatives and heterocyclic amines also underwent the photo-oxidation reaction over the MA-PI-7 catalyst to afford the corresponding imines with good activity. In addition, MA-PI-7 exhibited good stability over four successive photocatalytic cycles.
基金supported by the National Natural Science Foundation of China (21603125)Science-Education-Industry Integration Innovation Pilot Project of Qilu University of Technology (2020KJC-GH13)+2 种基金International Cooperation Project of Shandong Academy of Sciences (2019GHPY09)Natural Science Foundation of Shandong Province (ZR2019BEM025)Young doctor Cooperation Foundation of Qilu University of Technology (Shandong Academy of Sciences) (2019BSHZ0016)。
文摘A mesoporous UiO-66-NH_(2) aerogel is prepared via a straightforward sol-gel method without using any binders or mechanical pressures, in which the amine groups are directly introduced into the matrix by using 2-aminoterephthalic acid. The novel UiO-66-NH_(2) aerogel also exhibits high specific surface area and mesopore-dominated structure, implying its highly potential use in CO_(2) adsorption. For ulteriorly investigating the effect of amine loading on the CO_(2) adsorption ability, a series of UiO-66-NH_(2) aerogel with different amino content is fabricated by changing the ligand/metal molar ratio. When the molar ratio is 1.45, the CO_(2) adsorption capacity reaches the optimum value of 2.13 mmol·g^(-1) at 25 ℃ and 0.1 MPa, which is 12.2% higher than that of pure UiO-66 aerogel. Additionally, UiO-66-NH_(2)-1.45 aerogel also has noticeable CO_(2) selectivity against N_(2) and CH_(4) as well as good regeneration stability. Such results imply that it has good application prospect in the field of CO_(2) adsorption, and also contains the potential to be applied in catalysis, separation and other fields.
基金the support for this work from the National Natural Science Foundation of China [Grant Nos.32122046,32000959,82030067,and 82161160342]the National Key R&D Program [Grant No.2018YFA0703100]+3 种基金the Youth Innovation Promotion Association of CAS [Grant No.2019350]the Guangdong Natural Science Foundation [Grant No.2020A1515111190]the Shenzhen Fundamental Research Foundation [Grant Nos.JCYJ20190812162809131,JCYJ20200109114006014,JCYJ20210324113001005,JCYJ20210324115814040,and JSGGKQTD20210831174330015]the Shenzhen Fund for Guangdong Provincial High-level Clinical Key Specialties [Grant No.SZGSP001]。
文摘Numerous small-molecule amines(SMAs)play critical roles in maintaining bone homeostasis and promoting bone regeneration regardless of whether they are applied as drugs or biomaterials.On the one hand,SMAs promote bone formation or inhibit bone resorption through the regulation of key molecular signaling pathways in osteoblasts/osteoclasts;on the other hand,owing to their alkaline properties as well as their antioxidant and anti-inflammatory features,most SMAs create a favorable microenvironment for bone homeostasis.However,due to a lack of information on their structure/bioactivity and underlying mechanisms of action,certain SMAs cannot be developed into drugs or biomaterials for bone disease treatment.In this review,we thoroughly summarize the current understanding of SMA effects on bone homeostasis,including descriptions of their classifications,biochemical features,recent research advances in bone biology and related regulatory mechanisms in bone regeneration.In addition,we discuss the challenges and prospects of SMA translational research.
基金supported by the Science and Technology Development Fund,Macao,China(Grant No.:FDCT0044/2018/AFJ).
文摘Trace amines(TAs)are metabolically related to catecholamine and associated with cancer and neurological disorders.Comprehensive measurement of TAs is essential for understanding pathological processes and providing proper drug intervention.However,the trace amounts and chemical instability of TAs challenge quantification.Here,diisopropyl phosphite coupled with chip two-dimensional(2D)liquid chromatography tandem triple-quadrupole mass spectrometry(LC-QQQ/MS)was developed to simultaneously determine TAs and associated metabolites.The results showed that the sensitivities of TAs increased up to 5520 times compared with those using nonderivatized LC-QQQ/MS.This sensitive method was utilized to investigate their alterations in hepatoma cells after treatment with sorafenib.The significantly altered TAs and associated metabolites suggested that phenylalanine and tyrosine metabolic pathways were related to sorafenib treatment in Hep3B cells.This sensitive method has great potential to elucidate the mechanism and diagnose diseases considering that an increasing number of physiological functions of TAs have been discovered in recent decades.
基金supported by National Postdoctoral Program(2020M682073)the National Natural Science Foundation of China(NSFC,32061160477)+1 种基金The National Natural Science Foundation of China(32272315,32072209)the Natural Science Foundation of Guangdong Province(2022A1515010694).
文摘Meat products are an important part in our daily diet,providing valuable nutrients for the human body.However,heating processes cause the meat to become more appetizing with changes in texture,appearance,flavor,and chemical properties by the altering of protein structure and other ingredients.As one kind of cooking-induced contaminants,heterocyclic aromatic amines(HAAs)are widely present in protein aceous food products with strong carcinogenic and mutagenic properties.In order to promote the safety of traditional meat products,this review focused on the formation,metabolism,biological monitoring and inhibitory mechanism of HAA.An overview of the formation pathways,hazards,and control methods of HAAs during food processing in recent years was studied,aiming to provide some valuable information for exploring effective methods to inhibit the production of associated hazards during food processing.Systematic selection of different types of flavonoids to explore their effects on the formation of HAAs in an actual barbecue system can provide theoretical reference for effectively controlling the formation of HAAs and reducing their harm to human health.
文摘Polyamine-based scavenger resins containing 2, 3 and 4 nitrogen atoms have been prepared and their comparative efficacy to scavenge appropriate electrophilic chemicals (acids, acid chlorides, isocyanates and aldehydes) from solutions has been studied. As expected, the scavenging efficiency is directly proportional to the number of nucleophic nitrogens present on the resin. The results have been compared with the performance of the popular scavenger resin, namely, tris(2-aminoethyl)amine resin, to conclude that the low-cost polyamine resins now prepared can be conveniently used as effectively as the expensive commercial product.
文摘Differential heat of absorption of CO_2 in aqueous solutions of N,N-diethylethanolamine(DEEA) and activated DEEA solutions up to a total concentration of 2 mol·L^(-1) was measured as a function of CO_2 loading at 313.15 K using a reaction calorimeter. In order to analyze the performance of N-methyl-1,3-propanediamine(MAPA)as an activator, DEEA blended solutions containing 0.05, 0.1 and 0.2 mol·L^(-1) MAPA were studied. The heat of CO_2 absorption in single DEEA solutions was unaffected by changing the DEEA concentration in the range of(0.5–2) mol·L^(-1). On the other hand, increasing the concentration of MAPA in aqueous amine mixtures of(DEEA + MAPA) raised the heat of absorption.
基金financially supported by the National Natural Science Foundation of China(202102007,21978147 and 21935001)the Fundamental Research Funds for the Central Universities(buctrc202112)。
文摘Selective reductive amination of carbonyl compounds with high activity is very essential for the chemical and pharmaceutical industry,but scarcely successful paradigm was reported via efficient photocatalytic reactions.Herein,the ultrasmall Ru nanoclusters(~0.9 nm)were successfully fabricated over P25 support with positive charged Ru^(δ+)species at the interface.A new route was developed to achieve the furfural(FAL)to furfurylamine(FAM)by coupling the light-driven reductive amination and hydrogen transfer of ethanol over this type catalyst.Strikingly,the photocatalytic activity and selectivity are strongly dependent on the particle size and electronic structure of Ruthenium.The Ru^(δ+)species at the interface promote the formation of active imine intermediates;moreover,the Ru nanoclusters facilitate the separation efficiency of electrons and holes as well as accelerate the further hydrogenation of imine intermediates to product primary amines.In contrast Ru particles in larger nanometer size facilitate the formation of the furfuryl alcohol and excessive hydrogenation products.In addition,the coupling byproducts can be effectively inhibited via the construction of sub-nanocluster.This study offers a new path to produce the primary amines from biomass-derived carbonyl compounds over hybrid semiconductor/metal-clusters photocatalyst via light-driven tandem catalytic process.
基金supported by Chinese Academy of Sciences,China(Grant No.QYZDY-SSW-SLH013-2)Henan Normal University,China。
文摘Synthesizing nitrogen(N)-containing molecules from biomass derivatives is a new strategy for production of this kind of chemicals.Herein,for the first time we present the synthesis of N-substituted aryl pyrroles via reductive amination/cyclization of levulinic acid(LA)with primary aromatic amines and hydrosilanes(e.g.,PMHS)over Cs F,and a series of N-substituted aryl pyrroles could be obtained in good to excellent yields at 120○C.The mechanism investigation indicates that the reaction proceeds in two steps:the cyclization between amine and LA occurs first to form intermediate 5-methyl-N-alkyl-1,3-dihydro-2H-pyrrolones and their isomeride(B),and then the chemo-and region-selective reduction of intermediates take place to produce the final products.This approach for synthesis of N-substituted aryl pyrroles can be performed under mild and green conditions,which may have promising applications.
基金This work was supported financially by the National Key R&D Program of China(2018YFB1501500)National Natural Science Foundation of China(51976225).
文摘Since the utilization of abundant biomass to develop advanced materials has become an utmost priority in recent years,we developed two sustainable routes(i.e.,the impregnation method and the one-pot synthesis)to prepare the hydrochar-supported catalysts and tested its catalytic performance on the reductive amination.Several techniques,such as TEM,XRD and XPS,were adopted to characterize the structural and catalytic features of samples.Results indicated that the impregnation method favors the formation of outer-sphere surface complexes with porous structure as well as well-distributed metallic nanoparticles,while the one-pot synthesis tends to form the inner-sphere surface complexes with relatively smooth appearance and amorphous metals.This difference explains the better activity of catalysts prepared by the impregnation method which can selectively convert benzaldehyde to benzylamine with an excellent yield of 93.7%under the optimal reaction conditions;in contrast,the catalyst prepared by the one-pot synthesis only exhibits a low selectivity near to zero.Furthermore,the gram-scale test catalyzed by the same catalysts exhibits a similar yield of benzylamine in comparison to its smaller scale,which is comparable to the previously reported heterogeneous noble-based catalysts.More surprisingly,the prepared catalysts can be expediently recycled by a magnetic bar and remain the satisfying catalytic activity after reusing up to five times.In conclusion,these developed catalysts enable the synthesis of functional amines with excellent selectivity and carbon balance,proving cost-effective and sustainable access to the wide application of reductive amination.
基金supported by Zhejiang Provincial Natural Science Foundation of China(Grant No.LZ12E08002)
文摘Industrial grade multi-walled carbon nanotubes(IG-MWCNTs) are a low-cost substitute for commercially purified multi-walled carbon nanotubes(P-MWCNTs). In this work, IG-MWCNTs were functionalized with tetraethylenepentamine(TEPA) for CO2capture. The TEPA impregnated IG-MWCNTs were characterized with various experimental methods including N2adsorption/desorption isotherms, elemental analysis, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. Both the adsorption isotherms of IGMWCNTs-n and the isosteric heats of different adsorption capacities were obtained from experiments. TEPA impregnated IG-MWCNTs were also shown to have high CO2adsorption capacity comparable to that of TEPA impregnated P-MWCNTs. The adsorption capacity of IG-MWCNTs based adsorbents was in the range of 2.145 to 3.088 mmol/g, depending on adsorption temperatures. Having the advantages of low-cost and high adsorption capacity, TEPA impregnated IG-MWCNTs seem to be a promising adsorbent for CO2capture from flue gas.
文摘A testing method for N-nitrosamines and N-nitrosatable substances in rubber teats and soothers was modified. N-Nitrosamines are generally analyzed using either a nitrogen chemiluminescence detector (NCD) or a thermal energy analyzer (TEA). However, because few testing laboratories are equipped with these devices, it is difficult to conduct these tests. Therefore, an analysis method for N-nitrosamines using the more widespread gas chromatography-mass spectrometry (GC-MS) method was improved. In addition, EN 12868 was used to prepare the test solutions because of its worldwide use and compliance with EU regulations. Using GC-MS, EN 12868 method targeting ten kinds of N-nitrosamines was modified. The determination limits of the method were 1.0 -1.5 μg/kg for N-nitrosamines and 4 -6 μg/kg for N-nitrosatable substances. Quantification was possible at 1/5 or less and 1/15 or less, respectively, of the regulation values listed in EU Directive 93/11/EEC. In terms of application, there were no problems with the selectivity of the detector. The recoveries were 58% -109% for N-nitrosamines and 59% -102% for N-nitrosatable substances. Screening and verification were possible by measuring the amount of secondary amines in the boiled solution and migration solution.
基金supported by the Program for New Century Excellent Talents in University (No. NCET-06-0597)Ministry of Education 111 Project (No. B08049)
文摘Hemocyte counts and phenoloxidase(PO)activity were examined after hemolymph being incubated in dopamine(DA),noradrenaline(NE)and serotonin(5-HT).Results showed that all the three biogenic amines(BAs)had a significant impact on total hemocyte count(THC),differential hemocyte count(DHC),and intracelluar and extracelluar phenoloxidase(PO)activity.Among these Bas,DA had the strongest effect on the above parameters,whereas 5-HT had the least effect.Preincubation with D1 receptor antagonist SCH23390,D2 receptor antagonist Sulpiride and 1:1 admixture of the two could significantly inhibit the effect of DA on these parameters.SCH23390 showed a stronger inhibitory effect than Sulpiride,and the admixture exhibited the strongest effect.These results suggested that the change of hemocyte count and activation of prophenoloxidase(proPO)system in Litopenaeusvan-namei hemocyte can be regulated by BAs,and DA modulates the two parameters via its receptors.
文摘Biogenic amines are known to have various biological functions such as not only neurotransmitter and cell proliferation but also food poisoning. Bacterially-decomposed amines such as histamine, agmatine, putrescine, cadaverine, spermidine and spermine cause allergic symptoms. We developed simple method for measurement of polyamine as indicator of food decomposition with a fluorometer by using 4-(1-Pyrene)butyric acid N-hydroxysuccinimide ester (PSE). PSE reacts with primary and secondary amino moieties of polyamines and produces the intramolecular excimer fluorescence. Excimer fluorescence with broad peak at around 470 nm was clearly detected in linear type biogenic amines such as putrescine, cadaverine, spermidine and spermine at 10 mM. However neither histamine nor trimethylamine altered the fluorescence. Decomposed sardine and mackerel by improper storage showed stronger intensity than fresh ones. Comparing with OPA-method, PSE method was useful for screening biogenic amines present in food, esp. fish since the analysis was simple after one-step purification procedure. An inexpensive system which can rapidly detect biogenic amines from food is necessary in a medium and small-sized food business. The technique using excimer has potential to realize the high through-put screening system for evaluation of food freshness and is expected to bring the public interests such as food security and safety of consumer.
文摘Time resolved laser spectroscopy and GC/MS were used to investigate the primary processes and the side reactions occurring in benzophenone and chlorothioxanthone/amine systems used as photoinitiators of radical polymerization. The discrepancy observed between the experimental data and the expected behaviour is accounted for by detrimental chemical reaction involving the ketone triplet state, the ketyl radical and the amine-derived radical.
文摘The syntheses of N-Methyl-14C benzyl amine and N-Methyl-14C benzyl nitrosamine are reported. Specific activities were approximately 920 MBq/mmol. Chemical and radiochemical purity checked by HPLC were more than 95%.
