The preparation of bioactive derivatives from the renewable natural product pinene is a hot research topic in the deep processing and utilization of pinene.In this study,β-pinene was used to develop novel molecules a...The preparation of bioactive derivatives from the renewable natural product pinene is a hot research topic in the deep processing and utilization of pinene.In this study,β-pinene was used to develop novel molecules as a promising new precursor of insecticide.A series of amide-containing derivatives ofβ-pinene were synthesized and characterized.The insecticidal activities of these derivatives against Mythimna separate and Semiaphis heraclei were tested.The structure characterization results showed that the characterization data of amide-containing derivatives were in full agreement with their proposed structures.The insecticidal activities evaluation results indicated that amide-containing derivatives exhibited weak insecticidal activity against Mythimna separate,but exhibited moderate to good insecticidal activity against Semiaphis heraclei.After testing for 72 h,the corrected mortality against Semiaphis heraclei of compounds 5c,5e,5f,5 h,5j,and 5 m was 100%at 1000 mg/L.The structure-activity relationship analysis results showed that the introduction of an amide group into the structure of derivatives improved their insecticidal activity against Semiaphis heraclei.Meanwhile,the amide-containing derivatives containing the F and NO_(2) substituted benzene ring might improve their insecticidal activity against Semiaphis heraclei.This study will be helpful for the high value-added utilization of the natural renewable resourceβ-pinene and the development of novel insecticides.展开更多
Ternary strategy with a suitable third component is a successful strategy to improve the photovoltaic performance of organic solar cells(OSCs).Very recently,Y-series based giant molecule acceptors or oligomerized acce...Ternary strategy with a suitable third component is a successful strategy to improve the photovoltaic performance of organic solar cells(OSCs).Very recently,Y-series based giant molecule acceptors or oligomerized acceptors have emerged as promising materials for achieving highly efficient and stable binary OSCs,while application as third component for ternary OSCs is limited.Here a novelπ-extended giant dimeric acceptor,GDF,is developed based on central Y series core fusion and rigid BDT as linker,and then incorporated into the state-of-the-art PM1:PC6 system to construct ternary OSCs.The GDF has a near planar backbone,resulting in increasedπ-conjugation,excellent crystallinity,and good electron transport capacity.When GDF is introduced into the PM1:PC6 system,it ensues in a cascade like the lowest unoccupied molecular orbitals(LUMO)energy level alignment,a complementary absorption band with PM1 and PC6,higher and balanced hole and electron mobility,slightly smaller domain size,and a higher exciton dissociation probability for PM1:PC6:GDF(1:1.1:0.1)blend film.As a consequence,the PM1:PC6:GDF(1:1.1:0.1)ternary OSC achieves a champion PCE of 19.22%,with a significantly higher open-circuit voltage and short-circuit current density,compared to 18.45%for the PM1:PC6(1:1.2)binary OSC.Our findings show that employing aπ-extended giant dimeric acceptor as a third component significantly improves the photovoltaic performance of ternary OSCs.展开更多
The catalysis technology of propylene dimerization to form 4-methyl-1-pentene(4MP1)using a Cu-K/K_(2)CO_(3) solid base catalyst is a well-known heterogeneous catalytic reaction.In this study,the intrinsic kinetics of ...The catalysis technology of propylene dimerization to form 4-methyl-1-pentene(4MP1)using a Cu-K/K_(2)CO_(3) solid base catalyst is a well-known heterogeneous catalytic reaction.In this study,the intrinsic kinetics of propylene dimerization were studied in a fixed-bed continuous reactor.Internal and external diffusion during the dimerization reaction experiments were eliminated by adjusting the flow rate of the carrier gas and the particle size of the catalyst support.Then,the concentration changes of each substance at the outlet of the catalyst bed under different residence times were investigated.Moreover,the suitable reaction kinetics equations was derived using the Langmuir Hinshelwood-Hougen-Watson kinetic model.Finally,the activation energy for each reaction involved in the dimerization reaction was calculated.The activation energies of 4MP1,branched by-products,and 1-hexene were 115.0,150.8,and 177.4 kJ/mol,respectively.The effect of process conditions on propylene dimerization with solid base catalysts was studied through kinetic model simulation.By comparing the theoretical values obtained from the simulation with the experimental results,the applicability and accuracy of the kinetic model were verified.展开更多
Background: Postpartum hemorrhage (PPH) is the major contributor to maternal mortality and morbidity worldwide as well as in Tanzania. Studies have shown Pre-eclampsia as a risk indicator for Postpartum hemorrhage and...Background: Postpartum hemorrhage (PPH) is the major contributor to maternal mortality and morbidity worldwide as well as in Tanzania. Studies have shown Pre-eclampsia as a risk indicator for Postpartum hemorrhage and D-dimer tends to rise in women with pre-eclampsia. Few studies that have shown the association between D-dimer and PPH have been controversial and differ according to ethnicity and lifestyle. Hence there is no suitable reference interval for D-dimer in predicting Postpartum hemorrhage among women with pre-eclampsia. Broad Objective: This study aimed to assess the association, sensitivity, and specificity of D-dimer as a laboratory predictor of postpartum hemorrhage among women with pre-eclampsia at KCMC hospital. Methodology: This was a hospital-based analytical cross-sectional study conducted at KCMC Hospital in Northern Tanzania from September 2022 to March 2023. A total of 195 women with pre-eclampsia were included in this study. Plasma D-dimer levels were taken from women with pre-eclampsia pre-delivery. Haematocrit was compared before and after delivery, and a fall of 10% was considered as Postpartum hemorrhage together with clinical assessment of the patient. Participants were divided among those who had severe features and those who did not have severe features and were further categorized into those who had PPH and those who did not have PPH. Logistic regression was used to determine the association between D-dimer and PPH adjusting for other factors. The Receiver Operating Curve (ROC) was used to evaluate the predictive value. Results: Higher median D-dimer levels were seen among women who had PPH compared to those who had no PPH. D-dimer was seen to be associated with PPH, thus for every unit increase of µg/ml of D-dimer among women who had pre-eclampsia without severe features there was a 14% significant increase in the odds of having postpartum hemorrhage and a 45% significant increase of having postpartum hemorrhage among those who had pre-eclampsia with severe features. Furthermore, the cut-off point of a D-dimer level of 0.66 µg/ml significantly predicts postpartum hemorrhage with a sensitivity of 75% and specificity of 55%. For those who had no severe features the cut-off point was 0.53 µg/ml with a sensitivity of 95% and specificity of 53%, and for those who had severe features the cut-off point was 3.58 µg/ml with a sensitivity of 50% and specificity of 96%. Conclusion: D-dimer can be used to predict postpartum hemorrhage among pre-eclampsia, especially among those who have severe features. This shows that D-dimer has specificity in predicting PPH in women with pre-eclampsia and can be applied in clinical services to save women from maternal morbidity and mortality. Blood products such as fresh frozen plasma, platelets, and whole blood together with tranexamic acid should be readily available in women with pre-eclampsia especially those with severe features with a D-dimer level of 3.58 µg/ml and above during delivery as they are at high risk of developing PPH.展开更多
Secondary organic aerosol （SOA） formation from hydroxyl radical （OH.） initiated photooxidation of α-pinene was investigated in a home-made smog chamber. The size distribution of SOA particles was measured using a...Secondary organic aerosol （SOA） formation from hydroxyl radical （OH.） initiated photooxidation of α-pinene was investigated in a home-made smog chamber. The size distribution of SOA particles was measured using aerodynamic particle sizer spectrometer. The effects of illumination intensity and light application time on SOA formation for α-pinene were evaluated. Experimental results show that the concentration of SOA particles increased significantly with an increasing of illumination intensity, and the light application time, the concentration, and the size of SOA particles were also increased. In addition, the factors influencing the formation of SOA were discussed. In addition, this article compared the effect of α-pinene with that of toluene, and discussed the contribution of α-pinene to SOA formation.展开更多
The isomerization reaction of pinene is one of the most important chemical reactions in the deep processing of pinene. The purpose of this study is to improve the performance of the metatitanic acid by composite. The ...The isomerization reaction of pinene is one of the most important chemical reactions in the deep processing of pinene. The purpose of this study is to improve the performance of the metatitanic acid by composite. The composite metatitanic acid catalyst TiM was prepared by adding Mn elements in the preparation process. The catalytic performance of TiM was evaluated. Comparison of TiM and metatitanic acid catalyst(Ti-FGP), the reaction rate of TiM catalyst was faster, and after the reaction, the yield of camphene and tricyclene increased about 1%. The catalysts were characterized by an SEM, FT-IR and laser particle size analyzer. The results show that the pinene isomerization reaction requires the synergistic action of the Br?nsted acid and Lewis acid.Br?nsted acid has great influence on the activity of catalyst, and Lewis acid has a great influence on the selectivity of the catalyst. The structure and morphology of the catalyst have a certain effect on the selectivity of pinene isomerization reaction.展开更多
An indoor chamber facility is described for investigation of atmospheric aerosol chemistry. Two sets of α-pinene ozonolysis experiments were conducted in the presence of dry ammonium sulfate seed particle: ozone limi...An indoor chamber facility is described for investigation of atmospheric aerosol chemistry. Two sets of α-pinene ozonolysis experiments were conducted in the presence of dry ammonium sulfate seed particle: ozone limited experiments and α-pinene limited experiments. The concentration of gas phase and particle phase species was monitored continuously by on-line instruments and recorded automatically by data sampling system. The evolution of size distribution was measured by a scanning mobility particle sizer ...展开更多
A reliable kinetic model to describe the effects of various factors on the reaction rate and selectivity of pinene isomerization is developed. Furthermore, computational fluid dynamics(CFD) is applied to simulate the ...A reliable kinetic model to describe the effects of various factors on the reaction rate and selectivity of pinene isomerization is developed. Furthermore, computational fluid dynamics(CFD) is applied to simulate the solid–liquid dispersion in reactor. The catalyst Ti M is obtained by improving the composition and structure of hydrated titanium dioxide. The kinetic equation of pinene isomerization is deduced based on reaction mechanism and catalyst deactivation model. The kinetic equation of pinene isomerization reaction is fitted, and the results show that the fitted equation is correlated with the experimental data. The rate and selectivity of pinene isomerization reaction are affected by the amount of catalyst, deactivation of catalyst, structure of catalyst, reaction temperature and water content of catalyst. The solid–liquid distribution of the reactor is calculated by computational fluid dynamics numerical simulation, and the solid–liquid dispersion in commercial scale reactor is more uniform than that in lab-scale reactor.展开更多
Induced BVOC emissions from pyrolyzed plants that may accumulate in confined topographies have been a controversy for their role in wildfire eruptions or flashovers. α-pinene (C<sub>10</sub>H<sub>16...Induced BVOC emissions from pyrolyzed plants that may accumulate in confined topographies have been a controversy for their role in wildfire eruptions or flashovers. α-pinene (C<sub>10</sub>H<sub>16</sub>) is one of the most abundant monoterpenes emitted from pyrolyzed Mediterranean vegetation in wildfires. Its thermal degradation under fire thermal stresses produces a range of highly flammable gases. In order to identify these products, thermal degradation experiments were performed on α-pinene in a tubular furnace in an inert atmosphere and a high-temperature range (300°C - 900°C). The pyrolysis products were identified using gas chromatography (GC) linked to a tubular furnace outlet by which their retention times were compared with those of reference standards. The degradation products were mainly terpenoids, aliphatic hydrocarbons (methane, ethane, ethene, propane, propene, 1,3-butadiene, isoprene), and aromatics (benzene, toluene) in addition to hydrogen. The radical mechanisms of the chemical reactions associated with the formation of the products at different experimental temperatures were addressed and compared with the literature. Monoterpenes, butadiene, isoprene, aliphatic hydrocarbons, and aromatics formations from α-pinene were consistent with the literature. However, even if benzene has been identified in our experiments, we cannot support with certainty the mechanisms of its formation described in the literature since acetylene was not observed.展开更多
To investigate the collision processes of proton with the water dimer(H_(2)O)_(2)at 50 e V,the time-dependent density functional theory coupled with molecular dynamics nonadiabatically is applied.Six specific collisio...To investigate the collision processes of proton with the water dimer(H_(2)O)_(2)at 50 e V,the time-dependent density functional theory coupled with molecular dynamics nonadiabatically is applied.Six specific collision orientations with various impact parameters are considered.The reaction channels,the mass distribution and the fragmentation mass spectrum are explored.Among all launched samples,the probability of the channel of non-charge transfer scattering and charge transfer scattering is about 80%,hinting that the probability of fragmentation is about 20%.The reaction channel of proton exchange process 2 is taken as an example to exhibit the detailed microscopic dynamics of the collision process by inspecting the positions,the respective distance,the number of loss of electrons and the evolution of the electron density.The study of the mass distribution and the fragmentation mass spectrum shows that among all possible fragments,the fragment with mass 36 has the highest relative abundance of 65%.The relative abundances of fragments with masses 1,35,and 34are 20%,13%,and 1.5%,respectively.For the total electron capture cross section,the present calculations agree with the available measurements and calculations over the energy range from 50 e V to 12 ke V.展开更多
Nano drug delivery systems have made significant progress in delivering anticancer drugs camptothecin(CPT).However,many challenges for CPT delivery remain,including low drug loading efficiency,premature drug leakage,a...Nano drug delivery systems have made significant progress in delivering anticancer drugs camptothecin(CPT).However,many challenges for CPT delivery remain,including low drug loading efficiency,premature drug leakage,and poor cellular internalization.Herein,we report a novel dual-sensitive polypeptide-based micelle with remarkably high drug loading of CPT for cancer therapy.This self-assembled micelle possesses the following essential components for CPT:(1)pH-sensitive PEG(OHC-PEG-CHO)for prolonging blood circulation and allowing biocompatibility by shielding the cationic micelles,which can be detached under the tumor acidic microenvironment and facilitates the cellular uptake;(2)polypeptide polylysine-polyphenylalanine(PKF)synthesized via ring-opening polymerization for micelle formation and CPT analogue loading;(3)dimeric CPT(DCPT)with redox-sensitive linker for increasing CPT loading and ensuring drug release at tumor sites.Interestingly,the linear-like morphology of PEG-PKF/DCPT micelles was able to enhance their cellular internalization when compared with the spherical blank PKF micelles.Also,the anticancer efficacy of DCPT against lung cancer cells was significantly improved by the micelle formation.In conclusion,this work provides a promising strategy facilitating the safety and effective application of CPT in cancer therapy.展开更多
This article describes a method for synthesizing butyrolactone dimers using various inorganic silver salt catalysts.The method was successfully applied to alkyl 2-(2-bromopropyl)malonate 1,providing the dimeric butyro...This article describes a method for synthesizing butyrolactone dimers using various inorganic silver salt catalysts.The method was successfully applied to alkyl 2-(2-bromopropyl)malonate 1,providing the dimeric butyrolactone 2 when catalyzed by different silver salt catalysts.This synthesis method not only simplifies the original synthetic route,but also cleverly combines with natural product analogs,providing a strategy for the development of natural product polymer analogs in the future.展开更多
Bayesian inference is applied in this study to evaluate the posterior distribution of rate consents for a thermal isomerization of α-pinene by considering the uncertainty associated with rate constant parameters and ...Bayesian inference is applied in this study to evaluate the posterior distribution of rate consents for a thermal isomerization of α-pinene by considering the uncertainty associated with rate constant parameters and kinetic model structural error. The kinetic model of the thermal isomerization of α-pinene is shown to have a mathematically ill-conditioned system that makes it difficult to apply gradient-based optimization methods for rate constant evaluation. The Bayesian inference relates the posterior probability distribution of the rate constants to the likelihood probability of modeled concentration of reaction products meeting the experimentally measured concentration and the prior probability distribution of the parameters. A Markov chain Monte Carlo (MCMC) is used to draw samples from posterior distribution while the Bayesian inference relationship is considered. Multinomial random walk Metropolis-Hastings is applied in this study to construct the histograms of rate constants as well as the confidence intervals and the correlation coefficient matrix. Results showed that the Bayesian approach can successfully apply to estimate the confidence interval of rate constants of reaction model by taking into consideration the uncertainty.展开更多
Objective: To research the inhibitory effect on SGC-7901 cells of α-pinene, and the related mechanism of α-pinene. Methods: Used the MTT method to detect inhibition rate and western blotting to detect the influence ...Objective: To research the inhibitory effect on SGC-7901 cells of α-pinene, and the related mechanism of α-pinene. Methods: Used the MTT method to detect inhibition rate and western blotting to detect the influence on expression of ATM, Phos-S1981ATM, H2AX, γH2AX, CHK2 and p-CHK2, p53 and phos-p53 cell cycle related protein in SGC-7901 cells. Results: The research found α-pinene could inhibit the proliferation of SGC-7901 cells observably in vitro, and the inhibition rate assumes the dependence on concentration;and western blotting results showed that, α-pinene could activate phospho-ATM, increase the amount of γH2AX (p p < 0.05);increase the expression of p-CHK2, p53 and phos-p53 (p p p < 0.05);But there is no significant effect on expression of CHK2 (p > 0.05). Conclusions: α-pinene could inhibit the proliferation of SGC-7901 cells, and by inducing ATM (Ataxia Telangiectasia-Mutated) kinase signal pathway in DNA damage response, activating cell cycle checkpoint, making the cell cycle arrest then exerts its anti-tumor effects.展开更多
基金This work is financially supported by the Youth Talent Project of Major Academic and Technical Leaders Training Program of Jiangxi Province(Grant No.20204BCJL23045)the National Natural Science Foundation of China(Grant No.31800493)+1 种基金the Special Research Project on Camphor Tree(KRPCT)of Jiangxi Forestry Department(Grant No.2020CXZX07)the Innovative Leading Talent Short-Term Project in the Natural Science Area of Jiangxi Province(jxsq2018102072).
文摘The preparation of bioactive derivatives from the renewable natural product pinene is a hot research topic in the deep processing and utilization of pinene.In this study,β-pinene was used to develop novel molecules as a promising new precursor of insecticide.A series of amide-containing derivatives ofβ-pinene were synthesized and characterized.The insecticidal activities of these derivatives against Mythimna separate and Semiaphis heraclei were tested.The structure characterization results showed that the characterization data of amide-containing derivatives were in full agreement with their proposed structures.The insecticidal activities evaluation results indicated that amide-containing derivatives exhibited weak insecticidal activity against Mythimna separate,but exhibited moderate to good insecticidal activity against Semiaphis heraclei.After testing for 72 h,the corrected mortality against Semiaphis heraclei of compounds 5c,5e,5f,5 h,5j,and 5 m was 100%at 1000 mg/L.The structure-activity relationship analysis results showed that the introduction of an amide group into the structure of derivatives improved their insecticidal activity against Semiaphis heraclei.Meanwhile,the amide-containing derivatives containing the F and NO_(2) substituted benzene ring might improve their insecticidal activity against Semiaphis heraclei.This study will be helpful for the high value-added utilization of the natural renewable resourceβ-pinene and the development of novel insecticides.
基金supported by the Yunnan Fundamental Research Project(202301BF070001-009,KC-22222357)the Sichuan Science and Technology Program(2023NSFSC0990)the School of Materials Science and Engineering,Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications。
文摘Ternary strategy with a suitable third component is a successful strategy to improve the photovoltaic performance of organic solar cells(OSCs).Very recently,Y-series based giant molecule acceptors or oligomerized acceptors have emerged as promising materials for achieving highly efficient and stable binary OSCs,while application as third component for ternary OSCs is limited.Here a novelπ-extended giant dimeric acceptor,GDF,is developed based on central Y series core fusion and rigid BDT as linker,and then incorporated into the state-of-the-art PM1:PC6 system to construct ternary OSCs.The GDF has a near planar backbone,resulting in increasedπ-conjugation,excellent crystallinity,and good electron transport capacity.When GDF is introduced into the PM1:PC6 system,it ensues in a cascade like the lowest unoccupied molecular orbitals(LUMO)energy level alignment,a complementary absorption band with PM1 and PC6,higher and balanced hole and electron mobility,slightly smaller domain size,and a higher exciton dissociation probability for PM1:PC6:GDF(1:1.1:0.1)blend film.As a consequence,the PM1:PC6:GDF(1:1.1:0.1)ternary OSC achieves a champion PCE of 19.22%,with a significantly higher open-circuit voltage and short-circuit current density,compared to 18.45%for the PM1:PC6(1:1.2)binary OSC.Our findings show that employing aπ-extended giant dimeric acceptor as a third component significantly improves the photovoltaic performance of ternary OSCs.
基金supported by the National Natural Science Foundation of China under agreement number 22378026the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality(IDHT20180508).
文摘The catalysis technology of propylene dimerization to form 4-methyl-1-pentene(4MP1)using a Cu-K/K_(2)CO_(3) solid base catalyst is a well-known heterogeneous catalytic reaction.In this study,the intrinsic kinetics of propylene dimerization were studied in a fixed-bed continuous reactor.Internal and external diffusion during the dimerization reaction experiments were eliminated by adjusting the flow rate of the carrier gas and the particle size of the catalyst support.Then,the concentration changes of each substance at the outlet of the catalyst bed under different residence times were investigated.Moreover,the suitable reaction kinetics equations was derived using the Langmuir Hinshelwood-Hougen-Watson kinetic model.Finally,the activation energy for each reaction involved in the dimerization reaction was calculated.The activation energies of 4MP1,branched by-products,and 1-hexene were 115.0,150.8,and 177.4 kJ/mol,respectively.The effect of process conditions on propylene dimerization with solid base catalysts was studied through kinetic model simulation.By comparing the theoretical values obtained from the simulation with the experimental results,the applicability and accuracy of the kinetic model were verified.
文摘Background: Postpartum hemorrhage (PPH) is the major contributor to maternal mortality and morbidity worldwide as well as in Tanzania. Studies have shown Pre-eclampsia as a risk indicator for Postpartum hemorrhage and D-dimer tends to rise in women with pre-eclampsia. Few studies that have shown the association between D-dimer and PPH have been controversial and differ according to ethnicity and lifestyle. Hence there is no suitable reference interval for D-dimer in predicting Postpartum hemorrhage among women with pre-eclampsia. Broad Objective: This study aimed to assess the association, sensitivity, and specificity of D-dimer as a laboratory predictor of postpartum hemorrhage among women with pre-eclampsia at KCMC hospital. Methodology: This was a hospital-based analytical cross-sectional study conducted at KCMC Hospital in Northern Tanzania from September 2022 to March 2023. A total of 195 women with pre-eclampsia were included in this study. Plasma D-dimer levels were taken from women with pre-eclampsia pre-delivery. Haematocrit was compared before and after delivery, and a fall of 10% was considered as Postpartum hemorrhage together with clinical assessment of the patient. Participants were divided among those who had severe features and those who did not have severe features and were further categorized into those who had PPH and those who did not have PPH. Logistic regression was used to determine the association between D-dimer and PPH adjusting for other factors. The Receiver Operating Curve (ROC) was used to evaluate the predictive value. Results: Higher median D-dimer levels were seen among women who had PPH compared to those who had no PPH. D-dimer was seen to be associated with PPH, thus for every unit increase of µg/ml of D-dimer among women who had pre-eclampsia without severe features there was a 14% significant increase in the odds of having postpartum hemorrhage and a 45% significant increase of having postpartum hemorrhage among those who had pre-eclampsia with severe features. Furthermore, the cut-off point of a D-dimer level of 0.66 µg/ml significantly predicts postpartum hemorrhage with a sensitivity of 75% and specificity of 55%. For those who had no severe features the cut-off point was 0.53 µg/ml with a sensitivity of 95% and specificity of 53%, and for those who had severe features the cut-off point was 3.58 µg/ml with a sensitivity of 50% and specificity of 96%. Conclusion: D-dimer can be used to predict postpartum hemorrhage among pre-eclampsia, especially among those who have severe features. This shows that D-dimer has specificity in predicting PPH in women with pre-eclampsia and can be applied in clinical services to save women from maternal morbidity and mortality. Blood products such as fresh frozen plasma, platelets, and whole blood together with tranexamic acid should be readily available in women with pre-eclampsia especially those with severe features with a D-dimer level of 3.58 µg/ml and above during delivery as they are at high risk of developing PPH.
基金supported by the Knowledge Innovation Foundation of Chinese Academy of Sciences (No.KJCX2-YW-N24)
文摘Secondary organic aerosol （SOA） formation from hydroxyl radical （OH.） initiated photooxidation of α-pinene was investigated in a home-made smog chamber. The size distribution of SOA particles was measured using aerodynamic particle sizer spectrometer. The effects of illumination intensity and light application time on SOA formation for α-pinene were evaluated. Experimental results show that the concentration of SOA particles increased significantly with an increasing of illumination intensity, and the light application time, the concentration, and the size of SOA particles were also increased. In addition, the factors influencing the formation of SOA were discussed. In addition, this article compared the effect of α-pinene with that of toluene, and discussed the contribution of α-pinene to SOA formation.
基金supported by the Fujian Green Pine Co.,Ltd(NO.2016001)
文摘The isomerization reaction of pinene is one of the most important chemical reactions in the deep processing of pinene. The purpose of this study is to improve the performance of the metatitanic acid by composite. The composite metatitanic acid catalyst TiM was prepared by adding Mn elements in the preparation process. The catalytic performance of TiM was evaluated. Comparison of TiM and metatitanic acid catalyst(Ti-FGP), the reaction rate of TiM catalyst was faster, and after the reaction, the yield of camphene and tricyclene increased about 1%. The catalysts were characterized by an SEM, FT-IR and laser particle size analyzer. The results show that the pinene isomerization reaction requires the synergistic action of the Br?nsted acid and Lewis acid.Br?nsted acid has great influence on the activity of catalyst, and Lewis acid has a great influence on the selectivity of the catalyst. The structure and morphology of the catalyst have a certain effect on the selectivity of pinene isomerization reaction.
基金the National Natural ScienceFundation of China (No. 20637001)
文摘An indoor chamber facility is described for investigation of atmospheric aerosol chemistry. Two sets of α-pinene ozonolysis experiments were conducted in the presence of dry ammonium sulfate seed particle: ozone limited experiments and α-pinene limited experiments. The concentration of gas phase and particle phase species was monitored continuously by on-line instruments and recorded automatically by data sampling system. The evolution of size distribution was measured by a scanning mobility particle sizer ...
基金the National Ministry of Science and Technology of China(No.2017YFB0602401)the National Natural Science Foundation of China(No.21776173 and 21625603)+2 种基金the Program of Shanghai Subject Chief Scientist(No.18XD1402000)the Fujian Green Pine Co.,Ltd.the computational support from the Center for High Performance Computing,Shanghai Jiao Tong University for supporting this work。
文摘A reliable kinetic model to describe the effects of various factors on the reaction rate and selectivity of pinene isomerization is developed. Furthermore, computational fluid dynamics(CFD) is applied to simulate the solid–liquid dispersion in reactor. The catalyst Ti M is obtained by improving the composition and structure of hydrated titanium dioxide. The kinetic equation of pinene isomerization is deduced based on reaction mechanism and catalyst deactivation model. The kinetic equation of pinene isomerization reaction is fitted, and the results show that the fitted equation is correlated with the experimental data. The rate and selectivity of pinene isomerization reaction are affected by the amount of catalyst, deactivation of catalyst, structure of catalyst, reaction temperature and water content of catalyst. The solid–liquid distribution of the reactor is calculated by computational fluid dynamics numerical simulation, and the solid–liquid dispersion in commercial scale reactor is more uniform than that in lab-scale reactor.
文摘Induced BVOC emissions from pyrolyzed plants that may accumulate in confined topographies have been a controversy for their role in wildfire eruptions or flashovers. α-pinene (C<sub>10</sub>H<sub>16</sub>) is one of the most abundant monoterpenes emitted from pyrolyzed Mediterranean vegetation in wildfires. Its thermal degradation under fire thermal stresses produces a range of highly flammable gases. In order to identify these products, thermal degradation experiments were performed on α-pinene in a tubular furnace in an inert atmosphere and a high-temperature range (300°C - 900°C). The pyrolysis products were identified using gas chromatography (GC) linked to a tubular furnace outlet by which their retention times were compared with those of reference standards. The degradation products were mainly terpenoids, aliphatic hydrocarbons (methane, ethane, ethene, propane, propene, 1,3-butadiene, isoprene), and aromatics (benzene, toluene) in addition to hydrogen. The radical mechanisms of the chemical reactions associated with the formation of the products at different experimental temperatures were addressed and compared with the literature. Monoterpenes, butadiene, isoprene, aliphatic hydrocarbons, and aromatics formations from α-pinene were consistent with the literature. However, even if benzene has been identified in our experiments, we cannot support with certainty the mechanisms of its formation described in the literature since acetylene was not observed.
基金the National Natural Science Foundation of China(Grant Nos.11905160 and 11635003)the 333'project of Jiangsu Province(Grant No.BRA2020327)the Science Foundation of Wuxi Institute of Technology(Grant No.ZK201903).
文摘To investigate the collision processes of proton with the water dimer(H_(2)O)_(2)at 50 e V,the time-dependent density functional theory coupled with molecular dynamics nonadiabatically is applied.Six specific collision orientations with various impact parameters are considered.The reaction channels,the mass distribution and the fragmentation mass spectrum are explored.Among all launched samples,the probability of the channel of non-charge transfer scattering and charge transfer scattering is about 80%,hinting that the probability of fragmentation is about 20%.The reaction channel of proton exchange process 2 is taken as an example to exhibit the detailed microscopic dynamics of the collision process by inspecting the positions,the respective distance,the number of loss of electrons and the evolution of the electron density.The study of the mass distribution and the fragmentation mass spectrum shows that among all possible fragments,the fragment with mass 36 has the highest relative abundance of 65%.The relative abundances of fragments with masses 1,35,and 34are 20%,13%,and 1.5%,respectively.For the total electron capture cross section,the present calculations agree with the available measurements and calculations over the energy range from 50 e V to 12 ke V.
基金supported by the National Natural Science Foundation of China (51922111)the Science and Technology Development Fund, Macao SAR (File no. 0124/2019/A3)+1 种基金the University of Macao (File no. MYRG2022-00203-ICMS)Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials (2019B121205002)
文摘Nano drug delivery systems have made significant progress in delivering anticancer drugs camptothecin(CPT).However,many challenges for CPT delivery remain,including low drug loading efficiency,premature drug leakage,and poor cellular internalization.Herein,we report a novel dual-sensitive polypeptide-based micelle with remarkably high drug loading of CPT for cancer therapy.This self-assembled micelle possesses the following essential components for CPT:(1)pH-sensitive PEG(OHC-PEG-CHO)for prolonging blood circulation and allowing biocompatibility by shielding the cationic micelles,which can be detached under the tumor acidic microenvironment and facilitates the cellular uptake;(2)polypeptide polylysine-polyphenylalanine(PKF)synthesized via ring-opening polymerization for micelle formation and CPT analogue loading;(3)dimeric CPT(DCPT)with redox-sensitive linker for increasing CPT loading and ensuring drug release at tumor sites.Interestingly,the linear-like morphology of PEG-PKF/DCPT micelles was able to enhance their cellular internalization when compared with the spherical blank PKF micelles.Also,the anticancer efficacy of DCPT against lung cancer cells was significantly improved by the micelle formation.In conclusion,this work provides a promising strategy facilitating the safety and effective application of CPT in cancer therapy.
基金Project supported by the Natural Science Foundation of Shandong Province(No.ZR2021MB102).
文摘This article describes a method for synthesizing butyrolactone dimers using various inorganic silver salt catalysts.The method was successfully applied to alkyl 2-(2-bromopropyl)malonate 1,providing the dimeric butyrolactone 2 when catalyzed by different silver salt catalysts.This synthesis method not only simplifies the original synthetic route,but also cleverly combines with natural product analogs,providing a strategy for the development of natural product polymer analogs in the future.
文摘Bayesian inference is applied in this study to evaluate the posterior distribution of rate consents for a thermal isomerization of α-pinene by considering the uncertainty associated with rate constant parameters and kinetic model structural error. The kinetic model of the thermal isomerization of α-pinene is shown to have a mathematically ill-conditioned system that makes it difficult to apply gradient-based optimization methods for rate constant evaluation. The Bayesian inference relates the posterior probability distribution of the rate constants to the likelihood probability of modeled concentration of reaction products meeting the experimentally measured concentration and the prior probability distribution of the parameters. A Markov chain Monte Carlo (MCMC) is used to draw samples from posterior distribution while the Bayesian inference relationship is considered. Multinomial random walk Metropolis-Hastings is applied in this study to construct the histograms of rate constants as well as the confidence intervals and the correlation coefficient matrix. Results showed that the Bayesian approach can successfully apply to estimate the confidence interval of rate constants of reaction model by taking into consideration the uncertainty.
文摘Objective: To research the inhibitory effect on SGC-7901 cells of α-pinene, and the related mechanism of α-pinene. Methods: Used the MTT method to detect inhibition rate and western blotting to detect the influence on expression of ATM, Phos-S1981ATM, H2AX, γH2AX, CHK2 and p-CHK2, p53 and phos-p53 cell cycle related protein in SGC-7901 cells. Results: The research found α-pinene could inhibit the proliferation of SGC-7901 cells observably in vitro, and the inhibition rate assumes the dependence on concentration;and western blotting results showed that, α-pinene could activate phospho-ATM, increase the amount of γH2AX (p p < 0.05);increase the expression of p-CHK2, p53 and phos-p53 (p p p < 0.05);But there is no significant effect on expression of CHK2 (p > 0.05). Conclusions: α-pinene could inhibit the proliferation of SGC-7901 cells, and by inducing ATM (Ataxia Telangiectasia-Mutated) kinase signal pathway in DNA damage response, activating cell cycle checkpoint, making the cell cycle arrest then exerts its anti-tumor effects.
