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
The charge density of cellulose fibers is a key parameter in the papermaking systems,and this is particularly true for the Alkyl Ketene Dimer( AKD) paper sizing.Zeta potential and cationic demand are often used to cha...The charge density of cellulose fibers is a key parameter in the papermaking systems,and this is particularly true for the Alkyl Ketene Dimer( AKD) paper sizing.Zeta potential and cationic demand are often used to characterize these charges.Generally,a similar sizing performance would be obtained when the fibers with similar morphology and charge characteristics are used.However,in a mill trial,it was shown that three bleached birch pulp samples,with similar fiber morphology,and zeta potential,had different AKD sizing behaviors.In this study,the surface charges of these pulp samples,measured using the polyelectrolyte titration methods,were investigated.The results showed that lower sizing efficiency of fibers were due to their lower surface charges.It was concluded that the direct measurement of surface charge of cellulose fibers can be more appropriate to evaluate the AKD paper sizing efficiency.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
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National Natural Science Foundation of China(No.31370578)State Key Laboratory of Pulp and Paper Engineering,China(No.201508)
文摘The charge density of cellulose fibers is a key parameter in the papermaking systems,and this is particularly true for the Alkyl Ketene Dimer( AKD) paper sizing.Zeta potential and cationic demand are often used to characterize these charges.Generally,a similar sizing performance would be obtained when the fibers with similar morphology and charge characteristics are used.However,in a mill trial,it was shown that three bleached birch pulp samples,with similar fiber morphology,and zeta potential,had different AKD sizing behaviors.In this study,the surface charges of these pulp samples,measured using the polyelectrolyte titration methods,were investigated.The results showed that lower sizing efficiency of fibers were due to their lower surface charges.It was concluded that the direct measurement of surface charge of cellulose fibers can be more appropriate to evaluate the AKD paper sizing efficiency.
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.
