The conjugated polycycles show excellent optical and electrical properties that are suitable for application in various organic electronics.While most of attentions have been paid to polycycles having planar π-conjug...The conjugated polycycles show excellent optical and electrical properties that are suitable for application in various organic electronics.While most of attentions have been paid to polycycles having planar π-conjugated system,the curved polycycles seem amazing due to their unique physical and chemical features.The non-planar conjugated polycycles have been created with the geometries of bracelet,saddle,bowl,Mobius band,helicenes,etc.Among them,the bowl-shaped one is of growing interest owing to the multidiscipline applications such as synthetic intermediates for end-cap of carbon nanotube,coordination with metal ions,encapsulation of fullerenes,and fabrication of electronic devices.In this paper,we summarize the recent advances on the chemistry of the bowl-shaped conjugated polycycles,particularly on their synthesis and the further chemical modifications toward organic functional materials.展开更多
Furans bearing epoxy enolsilane units via a tether that incorporates a nitrogen heteroatom,undergo intramolecular(4+3)cycloadditions to generate bis-heteroatomic polycyclic adducts having piperidine moieties in their ...Furans bearing epoxy enolsilane units via a tether that incorporates a nitrogen heteroatom,undergo intramolecular(4+3)cycloadditions to generate bis-heteroatomic polycyclic adducts having piperidine moieties in their frameworks.The cycloadducts,ultimately derived from furfural,a renewal chemical feedstock,are obtained with up to 4:1 dr and with ee retained from the epoxide.展开更多
The conjecture E(k)≤k is proved to be true if and only if k=1, 2, 3, where E(k) is the cyclicity of condimension k generic elementary polycycles. It is also proved that the cyclicity of any codimension 3 ensembles ex...The conjecture E(k)≤k is proved to be true if and only if k=1, 2, 3, where E(k) is the cyclicity of condimension k generic elementary polycycles. It is also proved that the cyclicity of any codimension 3 ensembles except ensembles with "lips" is ≤6. By the way, the methods usually used in the study of cyclicity of polycycles such as derivation division algorithm, Khovanskii procedure and the method of critical point analysis are introduced.展开更多
The cyclicity of four classes of codimension 3 plnnar polycycles and ensembles containing a saddle-node and two hyperbdic saddles is dealt with. The exnct cyclicity or cyclicity bound of them is obtained by finitely-s...The cyclicity of four classes of codimension 3 plnnar polycycles and ensembles containing a saddle-node and two hyperbdic saddles is dealt with. The exnct cyclicity or cyclicity bound of them is obtained by finitely-smooth normal form theory.展开更多
This paper deals with the cyclicity of a kind of degenerate planar polycycles through a saddle-node P0 and two hyperbolic saddles P1 and P2, where the hyperbolicity ratio of the saddle P1 (which connects the saddle-no...This paper deals with the cyclicity of a kind of degenerate planar polycycles through a saddle-node P0 and two hyperbolic saddles P1 and P2, where the hyperbolicity ratio of the saddle P1 (which connects the saddle-node with hh-connection) is equal to 1 and that of the other saddle P2 is irrational. It is assumed that the connections between P0 to P2 and P0 to P1 keep unbroken. Then the cyclicity of this kind of polycycle is no more than m + 3 if the saddle P1 is of order m and the hyperbolicity ratio of P2 is bigger than m.Furthermore, the cyclicity of this polycycle is no more than 7 if the saddle P1 is of order 2 and the hyperbolicity ratio of P2 is located in the interval (1, 2).展开更多
This paper deals with the cyclicity of a kind of degenerate planar polycycles through a saddle-node and two hyperbolic saddles, where the hyperbolicity ratio of the saddle （which connects the saddle-node with hp-conn...This paper deals with the cyclicity of a kind of degenerate planar polycycles through a saddle-node and two hyperbolic saddles, where the hyperbolicity ratio of the saddle （which connects the saddle-node with hp-connection） is equal to 1 and that of the other saddle is irrational. It is obtained that the cyclicity of this kind of polycycle is no more than 5 if the hp-connection keeps unbroken under the C^∞ perturbations.展开更多
In this paper, we investigate the number and the distribution of the limit cycles bifurcated from a kind of degenerate planar polycycles through three singular points: a saddle-node P 0, a fine saddle P 1 with finite ...In this paper, we investigate the number and the distribution of the limit cycles bifurcated from a kind of degenerate planar polycycles through three singular points: a saddle-node P 0, a fine saddle P 1 with finite order m ∈ N, a contractive (attracting) saddle P 2 with the hyperbolicity ratio q 2(0) ? Q. The connection between P 0 and P 1 is of hh-type and the connection between P 0 and P 2 is of hp-type. It is assumed that the connections between P 0 to P 2 and P 0 to P 1 keep unbroken. We obtain that the cyclicity of this polycycle is not more than 3m + 1, which is linearly dependent on the order of the resonant saddle P 1. We also show that the cyclicity is not more than m + 3 if q 2(0) > m, and that the nearer q 2(0) is close to 1, the more the limit cycles are bifurcated.展开更多
Stimuli-responsive molecules are highly desirable in different scenario such as smart materials,bio-imaging,and environment monitoring.Herein,a series of hetero polycycles which show optical response toward chemical s...Stimuli-responsive molecules are highly desirable in different scenario such as smart materials,bio-imaging,and environment monitoring.Herein,a series of hetero polycycles which show optical response toward chemical stimuli are synthesized from trithiasumanene(TTS).The TTS is transformed into ortho-quinone form,which then undergoes three-component Debus-Radziszewski reaction with aldehydes and ammonia to give oxazole-fused TTS(2-6).The thiophene rings on 3-5 are selectively oxidized to thiophene-S,S-dioxides,affording 3-3O_(2)-5-3O_(2).It is found that the electronic structures of these compounds are governed by the sub-stituents on oxazole moiety and oxidation state of thiophene ring.Moreover,these hetero polycycles exhibit optical response toward different chemical stimuli.Particularly,compounds 6 and 3-3O_(2) can serve as fluorescence detectors for harmful chemicals sulfide ions(S2-/HS-)and aniline,respectively.This work indicates that TTS is a promising precursor for the creation of responsive materials.展开更多
By means of finitely-smooth normal form theory and the method of infinitesimal analysis,it is proved that the cyclicity of a planar codimension 3 polycycle S(2) is three and the complete bifurcation diagram is provided.
Polybrominated biphenyl ethers(PBDEs)and polycyclic aromatic hydrocarbons(PAHs)are commonly detected contaminants at e-waste recycling sites.Against the conventional wisdom that PBDEs and PAHs are highly immobile and ...Polybrominated biphenyl ethers(PBDEs)and polycyclic aromatic hydrocarbons(PAHs)are commonly detected contaminants at e-waste recycling sites.Against the conventional wisdom that PBDEs and PAHs are highly immobile and persist primarily in shallowsurface soils,increasing evidence shows that these compounds can leach into the groundwater.Herein,we compare the leachabilities of PBDEs vs.PAHs from contaminated soils collected at an e-waste recycling site in Tianjin,China.Considerable amounts of BDE-209(0.3–2 ng/L)and phenanthrene(42–106 ng/L),the most abundant PBDE and PAH at the site,are detected in the effluents of columns packed with contaminated soils,with the specific concentrations varying with hydrodynamic and solution chemistry conditions.Interestingly,the leaching potential of BDE-209 appears to be closely related to the release of colloidal mineral particles,whereas the leachability of phenanthrene correlates well with the concentration of dissolved organic carbon in the effluent,but showing essentially no correlation with the concentration of mineral particles.The surprisingly different trends of the leachability observed between BDE-209 and phenanthrene is counterintuitive,as PBDEs and PAHs often co-exist at e-waste recycling sites(particularly at the sites wherein incineration is being practiced)and share many similarities in terms of physicochemical properties.One possible explanation is that due to its extremely low solubility,BDE-209 predominantly exists in free-phase(i.e.,as solid(nano)particles),whereas the more soluble phenanthrene is mainly sorbed to soil organic matter.Findings in this study underscore the need to better understand the mobility of highly hydrophobic organic contaminants at contaminated sites for improved risk management.展开更多
The associations of polycyclic aromatic hydrocarbon(PAH)exposure with serum uric acid(SUA)or hyperuricemia have been rarely assessed.We aimed to investigate the relationships between urinary PAH metabolites and SUA or...The associations of polycyclic aromatic hydrocarbon(PAH)exposure with serum uric acid(SUA)or hyperuricemia have been rarely assessed.We aimed to investigate the relationships between urinary PAH metabolites and SUA or hyperuricemia among US adults and to explore the mediating role of systemic inflammation in the associations.A total of 10,307 US adults were conducted to assess the associations of seven urinary hydroxy–PAH with SUA and hyperuricemia and evaluate the role of C-reactive protein(CRP),a biomarker of systemic inflammation,in such associations.Results showed that each 1-unit increase in ln-transformed 2-hydroxynaphthalene(2-OHNa),1-hydroxyphenanthrene(1-OHPh),2&3-hydroxyphenanthrene(2&3-OHPh)and total hydroxyphenanthrene(OHPh)was associated with a 1.68(95%confidence interval(CI):0.19 to 3.17),2.46(0.78 to 4.13),3.34(1.59 to 5.09),and 2.99(1.23 to 4.75)μmol/L increase in SUA,and a 8%(odds ratio(OR):1.08,1.02 to 1.15),9%(OR:1.09,1.02 to 1.18),13%(OR:1.13,1.05 to 1.22),and 12%(OR:1.12,95%CI:1.03,1.21)increase in hyperuricemia,respectively.Co-exposure of seven PAHs was positively associated with SUA and hyperuricemia,with 2&3-OHPh showing the highest weight(components weights:0.83 and 0.78,respectively).The CRP mediated 11.47%and 10.44%of the associations ofΣOHPh and 2&3-OHPh with SUA and mediated 8.60%and 8.62%in associations ofΣOHPh and 2&3-OHPh with hyperuricemia,respectively.In conclusion,internal levels of PAH metabolites were associated with elevated SUA levels and the increased risk of hyperuricemia among US adults,and CRP played a mediating role in the associations.展开更多
This study investigated environmental distribution and human exposure of polycyclic aromatic hydrocarbons(PAHs)and their derivatives in one Chinese petroleum refinery facility.It was found that,following with high con...This study investigated environmental distribution and human exposure of polycyclic aromatic hydrocarbons(PAHs)and their derivatives in one Chinese petroleum refinery facility.It was found that,following with high concentrations of 16 EPA PAHs(∑Parent-PAHs)in smelting subarea of studied petroleum refinery facility,total derivatives of PAHs[named as XPAHs,including nitro PAHs(NPAHs),chlorinated PAHs(Cl-PAHs),and brominated PAHs(Br-PAHs)]in gas(mean=1.57×10^(4)ng/m^(3)),total suspended particulate(TSP)(mean=4.33×10^(3) ng/m^(3))and soil(mean=4.37×10^(3) ng/g)in this subarea had 1.76-6.19 times higher levels than those from other subareas of this facility,surrounding residential areas and reference areas,indicating that petroleum refining processes would lead apparent derivation of PAHs.Especially,compared with those in residential and reference areas,gas samples in the petrochemical areas had higher∑NPAH/∑PAHs(mean=2.18),but lower∑Cl-PAH/∑PAHs(mean=1.43×10^(-1))and∑Br-PAH/∑PAHs ratios(mean=7.49×10^(-2)),indicating the richer nitrification of PAHs than chlorination during petrochemical process.The occupational exposure to PAHs and XPAHs in this petroleum refinery facility were 24-343 times higher than non-occupational exposure,and the ILCR(1.04×10^(-4))for petrochemical workers was considered to be potential high risk.Furthermore,one expanded high-resolution screening through GC Orbitrap/MS was performed for soils from petrochemical area,and another 35 PAHs were found,including alkyl-PAHs,phenyl-PAHs and other species,indicat-ing that profiles and risks of PAHs analogs in petrochemical areas deserve further expanded investigation.展开更多
Polycyclic aromatic hydrocarbons(PAHs)are of great concern because they threaten pri-mary productivity,but their specific effects on ecosystem functioning are scarce,hindering a comprehensive understanding of their ec...Polycyclic aromatic hydrocarbons(PAHs)are of great concern because they threaten pri-mary productivity,but their specific effects on ecosystem functioning are scarce,hindering a comprehensive understanding of their ecological risks,especially in eutrophicwaters.The present study was conducted by adding PAHs to four marine phytoplankton species and showed that naphthalene(Nap)and phenanthrene(Phe)induced both stimulatory and in-hibitory effects(>50%)on urea and NO_(3)−uptake by phytoplankton species.In addition,the apparent stimulative effects(>50%)for NH_(4)^(+)were also observed.Overall,38.9%of the sam-ples exhibited stimulation effects after 24 h exposure,which increased to 61.1%after 96 h exposure.This suggested the existence of a lag period,during which a tolerant cell popula-tion could adapt to PAHs.Significant positive correlations(P<0.01)between low and high concentrations of PAH individuals demonstrated that the mode of action for both pollutants on nitrogen uptake by phytoplankton was the same.Species-specific responses were also observed,with 19.0%of Thalassiosira sp.and 24.0%of Tetraselmis sp.exhibited inhibition effects greater than 50%,while 40.9%of Karlodinium veneficum and 27.3%of Rhodomonas salina demonstrated stimulation effects exceeding 50%,providing a unique perspective for exploring the harmful algal bloom of the mixotrophic K.veneficum,in addition to the original consideration of nutrients.The internal mechanisms may lie in differences in energy consumption between N-forms,exposure time and chemical concentrations,aswell as mor-phological characteristics and biochemical structures of the species,which require further investigation.展开更多
Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons(PHCs)from soil,with a primary emphasis on terrestrial plant systems.However,the mechanism of how soil microbiomes influen...Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons(PHCs)from soil,with a primary emphasis on terrestrial plant systems.However,the mechanism of how soil microbiomes influence the dissipation of PHCs within a hygrophyte planting system has yet to be fully elucidated.This work concentrated on the potential evolution of soil microbiomes and their effects on PHC dissipation within the Suaeda salsa(L.)Pall.planting system in a pot experiment.Two representative compounds,polycyclic aromatic hydrocarbons(PAHs)and n-alkanes,were used as target PHCs.The findings revealed a significant efficiency in the dissipation of PHCs in soil with Suaeda salsa cultivation,particularly with respect to n-alkanes.The high dissipation efficiency of PHCs was the synergistic result of root accumulation and microbial biodegradation.The key microbes involved in PHC dissipation were revealed,with the dominant phylum Proteobacteria and genus Salinimicrobium.The alterations in microbial diversity and abundance were closely associated with root exudation and PHC exposure.Significant differences in enzyme activities,an indicator of soil health and fertility,were observed between the rhizospheric and non-rhizospheric soils,which was attributed to root exudation.This study offers novel insights into the phytoremediation potential for Suaeda in PHC-contaminated soils and serves as a valuable scientific reference for the phytoremediation of such soils.展开更多
Polycyclic compounds are widely found in natural products and drug molecules with important biological activities,which attracted the attention of many chemists.Phosphine-catalyzed nucleophilic addition is one of the ...Polycyclic compounds are widely found in natural products and drug molecules with important biological activities,which attracted the attention of many chemists.Phosphine-catalyzed nucleophilic addition is one of the most powerful tools for the construction of various cyclic compounds with the advantages of atom economy,mild reaction conditions and simplicity of operation.Allenolates,Morita−Baylis−Hillman(MBH)alcohols and their derivatives(MBHADs),electron-deficient olefins and alkynes are very efficient substrates in phosphine mediated annulations,which formed many phosphonium species such asβ-phosphonium enolates,β-phosphonium dienolates and vinyl phosphonium ylides as intermediates.This review describes the reactivities of these phosphonium zwitterions and summarizes the synthesis of polycycle compounds through phosphine-mediated intramolecular and intermolecular sequential annulations.Thus,a systematic summary of the research process based on the phosphine-mediated sequential annulations of allenolates,MBH alcohols and MBHADs,electron-deficient olefins and alkynes are presented in Chapters 2-6,respectively.展开更多
Hymoins A–C(1–3),three unusual polycyclic polyprenylated acylphloroglucinols(PPAPs)were isolated from the flowers of Hypericum monogynum.Hymoin A features the first intriguing 6/5/5/5/7 pentacyclic caged PPAP.Hymoin...Hymoins A–C(1–3),three unusual polycyclic polyprenylated acylphloroglucinols(PPAPs)were isolated from the flowers of Hypericum monogynum.Hymoin A features the first intriguing 6/5/5/5/7 pentacyclic caged PPAP.Hymoin B is characterized by an unprecedented rearranged 5/6/8 tricyclic ring system,while hymoin C represents the first rearranged PPAP with a fantastic spirocyclic 5/6/7 ring system.Their structures were established by extensive spectroscopic analysis,X-ray crystallography,and computational methods.The plausible biosynthetic routes for the compounds were also proposed.In oleic acid(OA)-induced HepG2 cells,all compounds exhibited significant lipid-lowering activity at the concentrations of 2–8μmol/L.Further mechanistic study implied that compound 1 exhibited excellent lipid-lowering activity in OA-induced HepG2 cells through inhibiting the proteins of free fatty acids synthesis and improving lipidolysis.展开更多
Size-fractionated particulate matter(PM_(2.5)and PM>_(2.5))was collected at a traffic site in Kanazawa,Japan in a seasonal sampling work in 2020.Nine polycyclic aromatic hydrocarbons(4-to 6-ring PAHs)were determine...Size-fractionated particulate matter(PM_(2.5)and PM>_(2.5))was collected at a traffic site in Kanazawa,Japan in a seasonal sampling work in 2020.Nine polycyclic aromatic hydrocarbons(4-to 6-ring PAHs)were determined in fine and coarse particles.The gas/particle partitioning coefficients(K_(p))of the PAHs were calculated from the supercooled liquid vapour pressure and octanol-air partitioning coefficient based on the relationships obtained in previous traffic pollution-related studies.Gaseous PAHs were estimated by K_(p) and the concentrations of PM and particulate PAHs.The concentrations of total PAHs were 32.5,320.1 and 5646.2 pg/m^(3) in the PM>_(2.5),PM_(2.5) and gas phases,respectively.Significant seasonal trends in PAHs were observed(particle phase:lowest in summer,gas phase:lowest in spring,particle and gas phase:lowest in spring).Compared to 2019,the total PAH concentrations(in particles)decreased in 2020,especially in spring and summer,which might be due to reduced traffic trips during the COVID-19 outbreak.The incremental lifetime cancer risk(ILCR)calculated from the toxic equivalent concentrations relative to benzo[a]pyrene(BaP_(eq))was lower than the acceptable limit issued by the US Environmental Protection Agency,indicating a low cancer risk in long-term exposure to current PAH levels.It is notable that gaseous PAHs considerably contributed to BaP_(eq) and ILCR(over 50%),which highlighted the significance of gaseous PAH monitoring for public health protection.This low-cost estimation method for gaseous PAHs can be expected to reliably and conveniently obtain PAH concentrations as a surrogate for traditional sampling in the future work.展开更多
Previous studies have reported a relationship between exposure to metals and polycyclic aromatic hydrocarbons(PAHs)and blood glucose levels,but whether the mechanisms are mediated by amino acids remains to be elucidat...Previous studies have reported a relationship between exposure to metals and polycyclic aromatic hydrocarbons(PAHs)and blood glucose levels,but whether the mechanisms are mediated by amino acids remains to be elucidated.We conducted a three-wave repeated measurement study involving 201 elderly individuals(aged≥50 years)from five communities in Beijing,China.We simultaneously measured eightmetals in both blood and urine,six monohydroxy PAHs in urine,and 23 amino acids in blood.Linear mixed-effects and sparse partial least squares models were used to evaluate the individual effects,and Bayesian kernel machine regression was employed to mixture effects.Mediation analysis was further used to explore whether amino acids mediators mediate the association.We observed significant associations of selenium and strontium with increased blood glucose.Additionally,blood copper,urinary nickel,as well as urinary 1+9 hydroxyphenanthrene,were associated with irregular blood glucose regulation.Moreover,we found that amino acids such as leucine,proline,and alanine may mediate the associations.This study is the first to investigate the effect of metals and PAHs on blood glucose homeostasis,while also exploring the mediating role of amino acids,offering new insights into the impact of metals and PAHs on blood glucose regulation.展开更多
基金the National Natural Science Foundation of China(Nos.21522203,21372111,and 21190034)State Key Laboratory of Applied Organic Chemistry for the financial support
文摘The conjugated polycycles show excellent optical and electrical properties that are suitable for application in various organic electronics.While most of attentions have been paid to polycycles having planar π-conjugated system,the curved polycycles seem amazing due to their unique physical and chemical features.The non-planar conjugated polycycles have been created with the geometries of bracelet,saddle,bowl,Mobius band,helicenes,etc.Among them,the bowl-shaped one is of growing interest owing to the multidiscipline applications such as synthetic intermediates for end-cap of carbon nanotube,coordination with metal ions,encapsulation of fullerenes,and fabrication of electronic devices.In this paper,we summarize the recent advances on the chemistry of the bowl-shaped conjugated polycycles,particularly on their synthesis and the further chemical modifications toward organic functional materials.
基金supported by the Research Grants Council General Research Fund (No. 17301314)
文摘Furans bearing epoxy enolsilane units via a tether that incorporates a nitrogen heteroatom,undergo intramolecular(4+3)cycloadditions to generate bis-heteroatomic polycyclic adducts having piperidine moieties in their frameworks.The cycloadducts,ultimately derived from furfural,a renewal chemical feedstock,are obtained with up to 4:1 dr and with ee retained from the epoxide.
文摘The conjecture E(k)≤k is proved to be true if and only if k=1, 2, 3, where E(k) is the cyclicity of condimension k generic elementary polycycles. It is also proved that the cyclicity of any codimension 3 ensembles except ensembles with "lips" is ≤6. By the way, the methods usually used in the study of cyclicity of polycycles such as derivation division algorithm, Khovanskii procedure and the method of critical point analysis are introduced.
文摘The cyclicity of four classes of codimension 3 plnnar polycycles and ensembles containing a saddle-node and two hyperbdic saddles is dealt with. The exnct cyclicity or cyclicity bound of them is obtained by finitely-smooth normal form theory.
基金This work was supported by the National Natural Science Foundation of China(Grant No.19901001).
文摘This paper deals with the cyclicity of a kind of degenerate planar polycycles through a saddle-node P0 and two hyperbolic saddles P1 and P2, where the hyperbolicity ratio of the saddle P1 (which connects the saddle-node with hh-connection) is equal to 1 and that of the other saddle P2 is irrational. It is assumed that the connections between P0 to P2 and P0 to P1 keep unbroken. Then the cyclicity of this kind of polycycle is no more than m + 3 if the saddle P1 is of order m and the hyperbolicity ratio of P2 is bigger than m.Furthermore, the cyclicity of this polycycle is no more than 7 if the saddle P1 is of order 2 and the hyperbolicity ratio of P2 is located in the interval (1, 2).
基金Project sponsored by National Science Foundation (19901001)
文摘This paper deals with the cyclicity of a kind of degenerate planar polycycles through a saddle-node and two hyperbolic saddles, where the hyperbolicity ratio of the saddle （which connects the saddle-node with hp-connection） is equal to 1 and that of the other saddle is irrational. It is obtained that the cyclicity of this kind of polycycle is no more than 5 if the hp-connection keeps unbroken under the C^∞ perturbations.
基金This work was supported by the National Natural Science Foundation of China(Grant No.10671020)
文摘In this paper, we investigate the number and the distribution of the limit cycles bifurcated from a kind of degenerate planar polycycles through three singular points: a saddle-node P 0, a fine saddle P 1 with finite order m ∈ N, a contractive (attracting) saddle P 2 with the hyperbolicity ratio q 2(0) ? Q. The connection between P 0 and P 1 is of hh-type and the connection between P 0 and P 2 is of hp-type. It is assumed that the connections between P 0 to P 2 and P 0 to P 1 keep unbroken. We obtain that the cyclicity of this polycycle is not more than 3m + 1, which is linearly dependent on the order of the resonant saddle P 1. We also show that the cyclicity is not more than m + 3 if q 2(0) > m, and that the nearer q 2(0) is close to 1, the more the limit cycles are bifurcated.
基金This work was supported by the National Key R&D Program of China(No.2017YFA0204903)the National Natural Science Foundation of China(No.21871119).
文摘Stimuli-responsive molecules are highly desirable in different scenario such as smart materials,bio-imaging,and environment monitoring.Herein,a series of hetero polycycles which show optical response toward chemical stimuli are synthesized from trithiasumanene(TTS).The TTS is transformed into ortho-quinone form,which then undergoes three-component Debus-Radziszewski reaction with aldehydes and ammonia to give oxazole-fused TTS(2-6).The thiophene rings on 3-5 are selectively oxidized to thiophene-S,S-dioxides,affording 3-3O_(2)-5-3O_(2).It is found that the electronic structures of these compounds are governed by the sub-stituents on oxazole moiety and oxidation state of thiophene ring.Moreover,these hetero polycycles exhibit optical response toward different chemical stimuli.Particularly,compounds 6 and 3-3O_(2) can serve as fluorescence detectors for harmful chemicals sulfide ions(S2-/HS-)and aniline,respectively.This work indicates that TTS is a promising precursor for the creation of responsive materials.
基金Project supported by the National Natural Science Foundation of China and the DEPF of China.
文摘By means of finitely-smooth normal form theory and the method of infinitesimal analysis,it is proved that the cyclicity of a planar codimension 3 polycycle S(2) is three and the complete bifurcation diagram is provided.
基金supported by the National Key Research and Development Program of China(No.2019YFC1804202)the National Natural Science Foundation of China(Nos.22020102004 and 22125603)+1 种基金Tianjin Municipal Science and Technology Bureau(No.21JCZDJC00280)the Fundamental Research Funds for the Central Universities,and the Ministry of Education of China(No.T2017002).
文摘Polybrominated biphenyl ethers(PBDEs)and polycyclic aromatic hydrocarbons(PAHs)are commonly detected contaminants at e-waste recycling sites.Against the conventional wisdom that PBDEs and PAHs are highly immobile and persist primarily in shallowsurface soils,increasing evidence shows that these compounds can leach into the groundwater.Herein,we compare the leachabilities of PBDEs vs.PAHs from contaminated soils collected at an e-waste recycling site in Tianjin,China.Considerable amounts of BDE-209(0.3–2 ng/L)and phenanthrene(42–106 ng/L),the most abundant PBDE and PAH at the site,are detected in the effluents of columns packed with contaminated soils,with the specific concentrations varying with hydrodynamic and solution chemistry conditions.Interestingly,the leaching potential of BDE-209 appears to be closely related to the release of colloidal mineral particles,whereas the leachability of phenanthrene correlates well with the concentration of dissolved organic carbon in the effluent,but showing essentially no correlation with the concentration of mineral particles.The surprisingly different trends of the leachability observed between BDE-209 and phenanthrene is counterintuitive,as PBDEs and PAHs often co-exist at e-waste recycling sites(particularly at the sites wherein incineration is being practiced)and share many similarities in terms of physicochemical properties.One possible explanation is that due to its extremely low solubility,BDE-209 predominantly exists in free-phase(i.e.,as solid(nano)particles),whereas the more soluble phenanthrene is mainly sorbed to soil organic matter.Findings in this study underscore the need to better understand the mobility of highly hydrophobic organic contaminants at contaminated sites for improved risk management.
基金supported by the Key Program of National Natural Science Foundation of China(No.82241088)the Natural Science Foundation of Hubei Province(No.2022CFB813).
文摘The associations of polycyclic aromatic hydrocarbon(PAH)exposure with serum uric acid(SUA)or hyperuricemia have been rarely assessed.We aimed to investigate the relationships between urinary PAH metabolites and SUA or hyperuricemia among US adults and to explore the mediating role of systemic inflammation in the associations.A total of 10,307 US adults were conducted to assess the associations of seven urinary hydroxy–PAH with SUA and hyperuricemia and evaluate the role of C-reactive protein(CRP),a biomarker of systemic inflammation,in such associations.Results showed that each 1-unit increase in ln-transformed 2-hydroxynaphthalene(2-OHNa),1-hydroxyphenanthrene(1-OHPh),2&3-hydroxyphenanthrene(2&3-OHPh)and total hydroxyphenanthrene(OHPh)was associated with a 1.68(95%confidence interval(CI):0.19 to 3.17),2.46(0.78 to 4.13),3.34(1.59 to 5.09),and 2.99(1.23 to 4.75)μmol/L increase in SUA,and a 8%(odds ratio(OR):1.08,1.02 to 1.15),9%(OR:1.09,1.02 to 1.18),13%(OR:1.13,1.05 to 1.22),and 12%(OR:1.12,95%CI:1.03,1.21)increase in hyperuricemia,respectively.Co-exposure of seven PAHs was positively associated with SUA and hyperuricemia,with 2&3-OHPh showing the highest weight(components weights:0.83 and 0.78,respectively).The CRP mediated 11.47%and 10.44%of the associations ofΣOHPh and 2&3-OHPh with SUA and mediated 8.60%and 8.62%in associations ofΣOHPh and 2&3-OHPh with hyperuricemia,respectively.In conclusion,internal levels of PAH metabolites were associated with elevated SUA levels and the increased risk of hyperuricemia among US adults,and CRP played a mediating role in the associations.
基金supported by the National Key Research and Development Program of China(No.2019YFC1804501)the National Natural Science Foundation of China(Nos.22036007 and 22122611)+1 种基金the Natural Science Foundation of Shandong Province(No.ZR2020ME228)the Introduction and Cultivation Plan for Young Innovative Talents of Colleges and Universities.
文摘This study investigated environmental distribution and human exposure of polycyclic aromatic hydrocarbons(PAHs)and their derivatives in one Chinese petroleum refinery facility.It was found that,following with high concentrations of 16 EPA PAHs(∑Parent-PAHs)in smelting subarea of studied petroleum refinery facility,total derivatives of PAHs[named as XPAHs,including nitro PAHs(NPAHs),chlorinated PAHs(Cl-PAHs),and brominated PAHs(Br-PAHs)]in gas(mean=1.57×10^(4)ng/m^(3)),total suspended particulate(TSP)(mean=4.33×10^(3) ng/m^(3))and soil(mean=4.37×10^(3) ng/g)in this subarea had 1.76-6.19 times higher levels than those from other subareas of this facility,surrounding residential areas and reference areas,indicating that petroleum refining processes would lead apparent derivation of PAHs.Especially,compared with those in residential and reference areas,gas samples in the petrochemical areas had higher∑NPAH/∑PAHs(mean=2.18),but lower∑Cl-PAH/∑PAHs(mean=1.43×10^(-1))and∑Br-PAH/∑PAHs ratios(mean=7.49×10^(-2)),indicating the richer nitrification of PAHs than chlorination during petrochemical process.The occupational exposure to PAHs and XPAHs in this petroleum refinery facility were 24-343 times higher than non-occupational exposure,and the ILCR(1.04×10^(-4))for petrochemical workers was considered to be potential high risk.Furthermore,one expanded high-resolution screening through GC Orbitrap/MS was performed for soils from petrochemical area,and another 35 PAHs were found,including alkyl-PAHs,phenyl-PAHs and other species,indicat-ing that profiles and risks of PAHs analogs in petrochemical areas deserve further expanded investigation.
基金supported by the National Natural Science Foundation of China(No.42277404)the State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River(No.AEHKF2023004)+2 种基金the National Key Research and Development Programof China(No.2022YFC3202703)the International Collaboration Program of Chinese Academy of Sciences(Nos.SAJC202403,067GJHZ2023034MI)the Autonomous Deployment Project of Key Laboratory of Lake andWatershed Science for Water Security(No.NKL2023-KP01).
文摘Polycyclic aromatic hydrocarbons(PAHs)are of great concern because they threaten pri-mary productivity,but their specific effects on ecosystem functioning are scarce,hindering a comprehensive understanding of their ecological risks,especially in eutrophicwaters.The present study was conducted by adding PAHs to four marine phytoplankton species and showed that naphthalene(Nap)and phenanthrene(Phe)induced both stimulatory and in-hibitory effects(>50%)on urea and NO_(3)−uptake by phytoplankton species.In addition,the apparent stimulative effects(>50%)for NH_(4)^(+)were also observed.Overall,38.9%of the sam-ples exhibited stimulation effects after 24 h exposure,which increased to 61.1%after 96 h exposure.This suggested the existence of a lag period,during which a tolerant cell popula-tion could adapt to PAHs.Significant positive correlations(P<0.01)between low and high concentrations of PAH individuals demonstrated that the mode of action for both pollutants on nitrogen uptake by phytoplankton was the same.Species-specific responses were also observed,with 19.0%of Thalassiosira sp.and 24.0%of Tetraselmis sp.exhibited inhibition effects greater than 50%,while 40.9%of Karlodinium veneficum and 27.3%of Rhodomonas salina demonstrated stimulation effects exceeding 50%,providing a unique perspective for exploring the harmful algal bloom of the mixotrophic K.veneficum,in addition to the original consideration of nutrients.The internal mechanisms may lie in differences in energy consumption between N-forms,exposure time and chemical concentrations,aswell as mor-phological characteristics and biochemical structures of the species,which require further investigation.
基金financially supported by the National Natural Science Foundation of China(Nos.22176025 and 22136007)the National Key Research and Development Program of China(No.2022YFC3701404)the Petro China Innovation Foundation(No.D2019-5007-0502)。
文摘Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons(PHCs)from soil,with a primary emphasis on terrestrial plant systems.However,the mechanism of how soil microbiomes influence the dissipation of PHCs within a hygrophyte planting system has yet to be fully elucidated.This work concentrated on the potential evolution of soil microbiomes and their effects on PHC dissipation within the Suaeda salsa(L.)Pall.planting system in a pot experiment.Two representative compounds,polycyclic aromatic hydrocarbons(PAHs)and n-alkanes,were used as target PHCs.The findings revealed a significant efficiency in the dissipation of PHCs in soil with Suaeda salsa cultivation,particularly with respect to n-alkanes.The high dissipation efficiency of PHCs was the synergistic result of root accumulation and microbial biodegradation.The key microbes involved in PHC dissipation were revealed,with the dominant phylum Proteobacteria and genus Salinimicrobium.The alterations in microbial diversity and abundance were closely associated with root exudation and PHC exposure.Significant differences in enzyme activities,an indicator of soil health and fertility,were observed between the rhizospheric and non-rhizospheric soils,which was attributed to root exudation.This study offers novel insights into the phytoremediation potential for Suaeda in PHC-contaminated soils and serves as a valuable scientific reference for the phytoremediation of such soils.
基金the National Natural Science Foundation of China(Nos.22171147 and 21871148)for the financial support。
文摘Polycyclic compounds are widely found in natural products and drug molecules with important biological activities,which attracted the attention of many chemists.Phosphine-catalyzed nucleophilic addition is one of the most powerful tools for the construction of various cyclic compounds with the advantages of atom economy,mild reaction conditions and simplicity of operation.Allenolates,Morita−Baylis−Hillman(MBH)alcohols and their derivatives(MBHADs),electron-deficient olefins and alkynes are very efficient substrates in phosphine mediated annulations,which formed many phosphonium species such asβ-phosphonium enolates,β-phosphonium dienolates and vinyl phosphonium ylides as intermediates.This review describes the reactivities of these phosphonium zwitterions and summarizes the synthesis of polycycle compounds through phosphine-mediated intramolecular and intermolecular sequential annulations.Thus,a systematic summary of the research process based on the phosphine-mediated sequential annulations of allenolates,MBH alcohols and MBHADs,electron-deficient olefins and alkynes are presented in Chapters 2-6,respectively.
基金financially supported by the National Natural Science Foundation of China(Nos.32270413,82060631,82160808,and 82360035)the Science and Technology Department of Guizhou Province(Nos.QKHJC 2020–1Z076,QKHJC-ZK[2023]YB156,QKHJC-ZK[2021]YB569,and QKHPTRC[2020]5008)+4 种基金Excellent Young Talents Plan of Guizhou Medical University(2023,No.106)the 13thbatch of outstanding young scientific and technological talents in Guizhou Province(No.QKHPTRC[2021]5633)Guizhou Science and Technology Innovation Talent Team(No.QKHPTRC–CXTD[2022]007)High-level Innovative Talents in Guizhou Province(Thousand Levels of Talent for Chunmao Yuan in 2018)the project of State Key Laboratory of Functions and Applications of Medicinal Plants,Guizhou Medical University(Nos.FAMP202102K and QJJ[2023]113)。
文摘Hymoins A–C(1–3),three unusual polycyclic polyprenylated acylphloroglucinols(PPAPs)were isolated from the flowers of Hypericum monogynum.Hymoin A features the first intriguing 6/5/5/5/7 pentacyclic caged PPAP.Hymoin B is characterized by an unprecedented rearranged 5/6/8 tricyclic ring system,while hymoin C represents the first rearranged PPAP with a fantastic spirocyclic 5/6/7 ring system.Their structures were established by extensive spectroscopic analysis,X-ray crystallography,and computational methods.The plausible biosynthetic routes for the compounds were also proposed.In oleic acid(OA)-induced HepG2 cells,all compounds exhibited significant lipid-lowering activity at the concentrations of 2–8μmol/L.Further mechanistic study implied that compound 1 exhibited excellent lipid-lowering activity in OA-induced HepG2 cells through inhibiting the proteins of free fatty acids synthesis and improving lipidolysis.
基金supported by the Bilateral Open Partnership Joint Research Projects of the Japan Society for the Promotion of Science,Japan(No.JPJSBP120219914)the CHOZEN Project of Kanazawa University,Japan(2019)the Cooperative Research Programs of Institute of Nature and Environmental Technology,Kanazawa University,Japan(22002,22013,22007)。
文摘Size-fractionated particulate matter(PM_(2.5)and PM>_(2.5))was collected at a traffic site in Kanazawa,Japan in a seasonal sampling work in 2020.Nine polycyclic aromatic hydrocarbons(4-to 6-ring PAHs)were determined in fine and coarse particles.The gas/particle partitioning coefficients(K_(p))of the PAHs were calculated from the supercooled liquid vapour pressure and octanol-air partitioning coefficient based on the relationships obtained in previous traffic pollution-related studies.Gaseous PAHs were estimated by K_(p) and the concentrations of PM and particulate PAHs.The concentrations of total PAHs were 32.5,320.1 and 5646.2 pg/m^(3) in the PM>_(2.5),PM_(2.5) and gas phases,respectively.Significant seasonal trends in PAHs were observed(particle phase:lowest in summer,gas phase:lowest in spring,particle and gas phase:lowest in spring).Compared to 2019,the total PAH concentrations(in particles)decreased in 2020,especially in spring and summer,which might be due to reduced traffic trips during the COVID-19 outbreak.The incremental lifetime cancer risk(ILCR)calculated from the toxic equivalent concentrations relative to benzo[a]pyrene(BaP_(eq))was lower than the acceptable limit issued by the US Environmental Protection Agency,indicating a low cancer risk in long-term exposure to current PAH levels.It is notable that gaseous PAHs considerably contributed to BaP_(eq) and ILCR(over 50%),which highlighted the significance of gaseous PAH monitoring for public health protection.This low-cost estimation method for gaseous PAHs can be expected to reliably and conveniently obtain PAH concentrations as a surrogate for traditional sampling in the future work.
基金supported by the Noncommunicable Chronic Diseases-National Science and Technology Major Project(No.2023ZD0513200)the National Natural Science Foundation of China(Nos.82404278 and 82404365)China Postdoctoral Science Foundation(Nos.2023M730317 and 2023T160066).
文摘Previous studies have reported a relationship between exposure to metals and polycyclic aromatic hydrocarbons(PAHs)and blood glucose levels,but whether the mechanisms are mediated by amino acids remains to be elucidated.We conducted a three-wave repeated measurement study involving 201 elderly individuals(aged≥50 years)from five communities in Beijing,China.We simultaneously measured eightmetals in both blood and urine,six monohydroxy PAHs in urine,and 23 amino acids in blood.Linear mixed-effects and sparse partial least squares models were used to evaluate the individual effects,and Bayesian kernel machine regression was employed to mixture effects.Mediation analysis was further used to explore whether amino acids mediators mediate the association.We observed significant associations of selenium and strontium with increased blood glucose.Additionally,blood copper,urinary nickel,as well as urinary 1+9 hydroxyphenanthrene,were associated with irregular blood glucose regulation.Moreover,we found that amino acids such as leucine,proline,and alanine may mediate the associations.This study is the first to investigate the effect of metals and PAHs on blood glucose homeostasis,while also exploring the mediating role of amino acids,offering new insights into the impact of metals and PAHs on blood glucose regulation.
