Organic room-temperature phosphorescence(RTP)materials have garnered considerable attention in the fields of biosensing,optoelectronic devices,and anticounterfeiting because of their substantial Stokes shifts,tunable ...Organic room-temperature phosphorescence(RTP)materials have garnered considerable attention in the fields of biosensing,optoelectronic devices,and anticounterfeiting because of their substantial Stokes shifts,tunable emission wavelengths,and prolonged lifetimes.These materials offer remarkable advantages for biological imaging applications by effectively reducing environmental autofluorescence and enhancing imaging resolution.Recently,host-guest systems have been employed as efficient approaches to fabricate pure-organic RTP materials for bioimaging,providing benefits such as controllable preparation and flexible modulation.Consequently,an increasing number of corresponding studies are being reported;however,a comprehensive systematic review is still lacking.Therefore,we summarize recent advances in the development of pureorganic RTP materials using host-guest systems with regard to bioimaging,including rigid matrices and sensitization.The challenge and potential of RTP for biological imaging are also proposed to promote the biomedical applications of organic RTP materials with excellent optical properties.展开更多
Amber can emit room temperature phosphorescence(RTP)under the well-known 365 nm fluorescence ultraviolet light.This paper is devoted to the phosphorescence study of 20 pieces of amber materials from the Dominican Repu...Amber can emit room temperature phosphorescence(RTP)under the well-known 365 nm fluorescence ultraviolet light.This paper is devoted to the phosphorescence study of 20 pieces of amber materials from the Dominican Republic,Mexico,Baltic sea,Myanmar,and Fushun,China.The results show that amber from the same geographic origin has similar shape in phosphorescence spectra.However,the shape of the amber phosphorescence spectra varies depending on their different localities.Burmite(amber from Myanmar)and Fushun amber have a bright yellow phosphorescence with a long lifetime,while the Dominican and Mexican ones are weaker and last shorter.The irradiation of Baltic amber becomes faint or even inert.Phosphorescence spectral Gaussian fitting results suggest an emission maximum near 550 nm in most amber samples.Their phosphorescence lifetime,analyzed through the exponential function fitting,is up to 1 second in Burmite and Fushun samples,shorter in the Dominican and Mexican ones,about 0.230 s,and the shortest in Baltic amber,close to 0.151 s.These variations of phosphorescence lifetime and intensity are related to the relative geological ages of these amber.It indicated that the phosphorescence agent was probably formed during the long geological time.While the anomaly occurred in Baltic amber,the only one found in a sea secondary deposit form,it demonstrated that the terrestrial geological environment these amber preserved has prevented the phosphorescence agent to be deactivated.展开更多
The reactive diluent prepared by siloxane modified Trimethylene oxide can improve the performance of the UV curing system.Therefore,1,7-bis[(3-ethyl-3-methoxyoxacylobutane)propyl]octadecylosiloxane(BEMOPOMTS)was synth...The reactive diluent prepared by siloxane modified Trimethylene oxide can improve the performance of the UV curing system.Therefore,1,7-bis[(3-ethyl-3-methoxyoxacylobutane)propyl]octadecylosiloxane(BEMOPOMTS)was synthesized from diethyl carbonate,trimethylopropanes,allyl bromide,and 1,1,3,3,5,5,7,7-octadecylosiloxane as the main raw materials.BEMOPOMTS can be used as reactive diluents in the field of cationic UV curing.It has good thermal stability,and the addition of BEMOPOMTS significantly improves the tensile strength and elongation at break of epoxy resin.Compared with the pure epoxy resin,adding 20%BEMOPOMTS increased the elastic modulus by 25%to 677 MPa.展开更多
Internal curing agents (ICA) based on super absorbent polymer have poor alkali tolerance and reduce the early strength of concrete.An alkali tolerate internal curing agent (CAA-ICA) was designed and prepared by using ...Internal curing agents (ICA) based on super absorbent polymer have poor alkali tolerance and reduce the early strength of concrete.An alkali tolerate internal curing agent (CAA-ICA) was designed and prepared by using sodium carboxymethyl starch (CMS) with high hydrophilicity,acrylic acid (AA) containing anionic carboxylic group and acrylamide (AM) containing non-ionic amide group as the main raw materials.The results show that the ratio of CAA-ICA alkali absorption solution is higher than that existing ICA,which solves the low water absorption ratio of the ICA in alkali environment.The water absorption ratio of CAA-ICA in saturated Ca(OH)_(2) solution is 95.8 g·g^(-1),and the alkali tolerance coefficient is 3.4.The application of CAA-ICA in cement-based materials can increase the internal relative humidity and miniaturize the pore structure.The compressive strength of mortar increases up to 12.95%at 28 d,which provids a solution to overcome the reduction of the early strength.展开更多
[Objectives]This study was conducted to compare the effects of different curing processes on the characteristics of marinated beef.[Methods]Marinated beef was obtained by two curing processes:static curing and injecti...[Objectives]This study was conducted to compare the effects of different curing processes on the characteristics of marinated beef.[Methods]Marinated beef was obtained by two curing processes:static curing and injection and vacuum tumbling curing.The effects of the two curing processes on the production rate,curing absorption rate,water content,soluble protein content,amino acid nitrogen content,texture characteristics and microstructure of the product were compared.[Results]Compared with static curing,the production rate of marinated beef increased by 10%,the curing absorption rate increased by 28%,the texture and microstructure were improved,and the water content increased,while the soluble protein content decreased.As a result,the sensory score was higher.There was no significant difference in the content of amino acid nitrogen,but it decreased compared with raw meat.To sum up,injection and vacuum tumbling curing is more conducive to the processing of marinated beef.[Conclusions]This study provides a theoretical basis for the industrial production of marinated beef,and lays a foundation for in-depth exploration of injection and vacuum tumbling curing technique of marinated beef.展开更多
Achievement of a‘clinical cure’in chronic hepatitis B(CHB)implies sustained virological suppression and immunological control over the infection,which is the ideal treatment goal according to domestic and internatio...Achievement of a‘clinical cure’in chronic hepatitis B(CHB)implies sustained virological suppression and immunological control over the infection,which is the ideal treatment goal according to domestic and international CHB management guidelines.Clinical practice has shown encouraging results for specific patient cohorts using tailored treatment regimens.These regimens incorporate either nucleos(t)ide analogs,immunomodulatory agents such as pegylated interferonα,or a strategic combination of both,sequentially or concurrently administered.Despite these advancements in the clinical handling of hepatitis B,achieving a clinical cure remains elusive for a considerable subset of patients due to the number of challenges that preclude the realization of optimal treatment outcomes.These include,but are not limited to,the emergence of antiviral resistance,incomplete immune recovery,and the persistence of covalently closed circular DNA.Moreover,the variance in response to interferon therapy and the lack of definitive biomarkers for treatment cessation also contribute to the complexity of achieving a clinical cure.This article briefly overviews the current research progress and existing issues in pursuing a clinical cure for hepatitis B.展开更多
Classical survival analysis assumes all subjects will experience the event of interest, but in some cases, a portion of the population may never encounter the event. These survival methods further assume independent s...Classical survival analysis assumes all subjects will experience the event of interest, but in some cases, a portion of the population may never encounter the event. These survival methods further assume independent survival times, which is not valid for honey bees, which live in nests. The study introduces a semi-parametric marginal proportional hazards mixture cure (PHMC) model with exchangeable correlation structure, using generalized estimating equations for survival data analysis. The model was tested on clustered right-censored bees survival data with a cured fraction, where two bee species were subjected to different entomopathogens to test the effect of the entomopathogens on the survival of the bee species. The Expectation-Solution algorithm is used to estimate the parameters. The study notes a weak positive association between cure statuses (ρ1=0.0007) and survival times for uncured bees (ρ2=0.0890), emphasizing their importance. The odds of being uncured for A. mellifera is higher than the odds for species M. ferruginea. The bee species, A. mellifera are more susceptible to entomopathogens icipe 7, icipe 20, and icipe 69. The Cox-Snell residuals show that the proposed semiparametric PH model generally fits the data well as compared to model that assume independent correlation structure. Thus, the semi parametric marginal proportional hazards mixture cure is parsimonious model for correlated bees survival data.展开更多
Some people,mainly in the West,were taken by surprise when six Chinese warships were seen near the Red Sea in October 2023 amid the conflict in Gaza.Some Western media and politicians tried to frame China’s mission a...Some people,mainly in the West,were taken by surprise when six Chinese warships were seen near the Red Sea in October 2023 amid the conflict in Gaza.Some Western media and politicians tried to frame China’s mission as an escalatory move in the Middle East.展开更多
National food security is the backbone of any economy,and achieving food security is essential for the prosperity of a nation.During my study in China at the Institute of South-South Cooperation and Development,Peking...National food security is the backbone of any economy,and achieving food security is essential for the prosperity of a nation.During my study in China at the Institute of South-South Cooperation and Development,Peking University,from September 2022 to July 2023,I leant how China has managed to achieve food security despite its large population of around 1.4 billion and numerous other challenges by means of strategic planning,e"ective policy execution,technological advancement and global collaboration.展开更多
By using HDI and TMP as the main raw materials,polyethylene glycol 400(PEG400)is used as a non-ionic hydrophilic modifier,and sodium hydroxyethyl sulfonate is used as an ionic hydrophilic modifier to synthesize a dual...By using HDI and TMP as the main raw materials,polyethylene glycol 400(PEG400)is used as a non-ionic hydrophilic modifier,and sodium hydroxyethyl sulfonate is used as an ionic hydrophilic modifier to synthesize a dual hydrophilic modified polyurethane curing agent.Research revealed that introducing PEG400 for hydrophilic chain segments and sodium hydroxyethyl sulfonate for hydrophilic ionic groups in the polyurethane curing agent component leads to a uniform distribution of hydrophilic components,significantly enhancing compatibility with the aqueous polyol component,and results in excellent film performance.The synthesis process and film were characterized using Fourier transform infrared spectroscopy and high-resolution scanning electron microscopy in the study.展开更多
This paper examines the application of polyurethane curing technology in the construction of railway track beds,with a specific focus on its implementation in China’s rapidly developing railway infrastructure.The stu...This paper examines the application of polyurethane curing technology in the construction of railway track beds,with a specific focus on its implementation in China’s rapidly developing railway infrastructure.The study begins by identifying the limitations of traditional ballasted track beds,especially under the demands of high-speed and heavyload railways.It then methodically analyzes the advantages of polyurethane-cured track beds,highlighting their improved mechanical properties,including enhanced stability and durability.The paper further explores the benefits of transitioning to prefabricated polyurethane track beds,emphasizing significant cost reductions,better construction quality,and enhanced maintainability.Through a detailed review of experimental data and practical applications,the paper demonstrates the efficacy of polyurethane track beds in various railway settings.A critical part of the research involves optimizing the structural parameters of polyurethane track beds to achieve the best balance of mechanical and damping properties.The conclusion of the paper underscores the potential of polyurethane curing technology as a transformative approach to railway track bed construction,offering a solution to the challenges posed by traditional methods and aligning with the evolving needs of modern railways.展开更多
The cure kinetics of diglycidyl ether of bisphenol A (DGEBA) with hyperbranched poly (3-hydroxyphenyl) phosphate(HHPP) as the curing agent was investigated by means of non-isothermal differential scanning calori...The cure kinetics of diglycidyl ether of bisphenol A (DGEBA) with hyperbranched poly (3-hydroxyphenyl) phosphate(HHPP) as the curing agent was investigated by means of non-isothermal differential scanning calorimetry (DSC) at various heating rates. The results were compared with the corresponding results by using 1,3-dihydroxybenzene(DHB) as a model compound. The results show that HHPP can enhance the cure reaction of DGEBA, resulting in the decrease of the peak temperature of the curing curve as well as the decrease of the activation energy because of the flexible --P--O-- groups in the backbone of HHPP. However, both the activation energy of the cured polymer and the peak temperature of the curing curve are increased with DHB as a curing agent. The cure kinetics of the DGEBA/HHPP system was calculated by using the isoconversional method given by Malek. It was found that the two-parameter autocatalytic model(Sestak-Berggren equation) is the most adequate one to describe the cure kinetics of the studied System at various heating rates. The obtained non-isothermal DSC curves from the experimental data show the results being accordant with those theoretically calculated.展开更多
The mechanism of carotenoid degradation and the changes in the activities of related enzymes in flue-cured tobacco at the leaf-drying stage during the bulk-curing process were studied in order to provide theoretical b...The mechanism of carotenoid degradation and the changes in the activities of related enzymes in flue-cured tobacco at the leaf-drying stage during the bulk-curing process were studied in order to provide theoretical basis for optimization of curing technology. The effect of different rising speeds of temperature on the carotenoid degradation and the related enzymes activities at the color-fixing stage during the bulk curing process was studied by using the electric-heated fluecuring barn designed by Henan Agricultural University, China, based on curing technology with yellowing at low temperature and moderate humidity and leaf drying at moderate humidity. The results showed that the carotenoid degradation components (β-carotene, lutein, neoxanthin, and violaxthin) decreased gradually at the color-fixing stage during the bulk curing process. The carotenoid degradation components viz.,β-carotene, lutein, neoxanthin, and violaxthin at the slow heating curing (T1) were relatively higher than the rapid heating curing (T2) accounting for 10, 2, 32 and 32% respectively, but there were no differences among treatments (P〉 0.05). The effect of different conditions of curing on the activities of enzymes related to carotenoids degradation were significant. The lipoxygenase, phenylalanine ammonialyase, peroxidase, and polyphenol oxidase enzymes had a bidirectional effect on the quality of tobacco leaves and it was beneficial to form more premise matter of aroma based on the higher enzyme activities at the early leaf-drying stage. The slow heating could regulate the change in various enzymes' activities reasonably, making cell redox reaction to reach the dynamic balance and make the degradation of carotenoids adequately. Meanwhile, it could avoid the occurrence of browning reaction and provide foundation for improving the quality of tobacco and optimization of technology for bulk curing and further enhancing aroma.展开更多
La0.5Sm0.2Sr0.3MnO3/(Ag2O)x/2 (x = 0.00, 0.04, 0.08, 0.25, 0.30) samples were prepared by the solid-state reaction method, and their transport behaviors, transport mechanism, and magnetoresistance effect were stud...La0.5Sm0.2Sr0.3MnO3/(Ag2O)x/2 (x = 0.00, 0.04, 0.08, 0.25, 0.30) samples were prepared by the solid-state reaction method, and their transport behaviors, transport mechanism, and magnetoresistance effect were studied through the measurement and fitting of p-T curves. The results show that the element Ag takes part in reaction when the doping amount is small. Ag is mainly distributed at the grain boundary of the host material and is in metallic state when the doping amount is relatively large; then the system becomes a two-phase composite. A small amount of Ag doping can apparently increase grain-boundary magnetoresistance induced by the spin-dependent scattering. The resistivity of the sample doped with 30 mol% Ag is one order of magnitude smaller than that of low-doped samples, and its magnetoresistance in the magnetic field of 0.5 T and at 300 K is strengthened apparently reaching 9.4%, which is connected not only with the improvement of the grain-boundary structure of the host material but also with the decrease of material resistivity.展开更多
Low-temperature assembly of MXene nanosheets into three-dimensional(3D) robust aerogels addresses the crucial stability concern of the nano-building blocks during the fabrication process,which is of key importance for...Low-temperature assembly of MXene nanosheets into three-dimensional(3D) robust aerogels addresses the crucial stability concern of the nano-building blocks during the fabrication process,which is of key importance for transforming the fascinating properties at the nanoscale into the macroscopic scale for practical applications.Herein,suitable cross-linking agents(amino-propyltriethoxysilane,Mn^(2+),Fe^(2+),Zn^(2+),and Co^(2+)) as interfacial mediators to engineer the interlayer interactions are reported to realize the graphene oxide(GO)-assisted assembly of Ti_(3)C_(2)T_(x) MXene aerogel at room temperature.This elaborate aerogel construction not only suppresses the oxidation degradation of Ti_(3)C_(2)T_(x) but also generates porous aerogels with a high Ti_(3)C_(2)T_(x) content(87 wt%) and robustness,thereby guaranteeing the functional accessibility of Ti_(3)C_(2)T_(x) nanosheets and operational reliability as integrated functional materials.In combination with a further sulfur modification,the Ti_(3)C_(2)T_(x) aerogel electrode shows promising electrochemical performances as the freestanding anode for sodium-ion storage.Even at an ultrahigh loading mass of 12.3 mg cm^(-2),a pronounced areal capacity of 1.26 mAh cm^(-2) at a current density of 0.1 A g^(-1) has been achieved,which is of practical significance.This work conceptually suggests a new way to exert the utmost surface functionalities of MXenes in 3D monolithic form and can be an inspiring scaffold to promote the application of MXenes in different areas.展开更多
Synthesis and applications of three-dimensional(3 D)porous graphene frameworks(GFs)have attracted extensive interest owing to their intriguing advantages of high specific surface area,enriched porosity,excellent elect...Synthesis and applications of three-dimensional(3 D)porous graphene frameworks(GFs)have attracted extensive interest owing to their intriguing advantages of high specific surface area,enriched porosity,excellent electrical conductivity,exceptional compressibility and processability.However,it is still challenging for economically viable,fast and scalable assembly of 3 D GFs at room-temperature.Herein,we reported a one-step scalable strategy for fast self-assembly of graphene oxide into 3 D macroscopically porous GFs,with assistance of polyoxometalates(POM)as functional cross-linker and hydrazine hydrate as reductant at room-temperature.The resulting 3 D interconnected macroporous POM-GFs uniformly decorated with ultrasmall POM nanoclusters were directly processed into binder-/additive-free film compact electrodes(1.68 g cm^(-3))with highly aligned,layer-stacked structure and electrically conductivity(622 S m-1)for high-performance supercapacitors,showing an impressive gravimetric capacitance of205 F g-1,volumetric capacitance of 334 F cm^(-3) at 1 mV s^(-1),and remarkable cycling stability with capacitance retention of 83%after 10,000 cycles,outperforming the most reported GFs.Further,the solid-state supercapacitors offered excellent gravimetric capacitance of 157 F g-1 exceptionally volumetric capacitance of 115 F cm^(-3) at 2 mV s^(-1) based on single electrode,and volumetric energy density of2.6 mWh cm^(-3).Therefore,this work will open novel opportunities to room-temperature fast assembly of 3 D porous graphene architectures for high-energy-density supercapacitors.展开更多
[ Objective] This study aimed to investigate the curing performance of polyurethane curing barn and reduce the cost of tobacco leaf flue-curing. [ Meth- odl The temperature control effect, curing effect and curing cos...[ Objective] This study aimed to investigate the curing performance of polyurethane curing barn and reduce the cost of tobacco leaf flue-curing. [ Meth- odl The temperature control effect, curing effect and curing cost of polyurethane curing barn and traditional bulk curing barn were analyzed and compared. [ Re- suit] The results showed that there were no significant differences in curing performance between two types of curing barns. Horizontal temperature differences in- creased slightly as the temperature rose. Specifically, horizontal temperature differences between each layer ranged from 0.2 ~C to 0.5 ~. Both two types of curing barns exhibited uniform air distribution. Polyurethane curing barn exhibited stable vertical temperature differences. Both two types of curing barns presented good curing effects with slight differences. Polyurethane curing barn exhibited higher economic benefits, lower coal cost, lower electricity cost, lower labor cost and lon- ger service life than traditional bulk curing barn, but its construction cost was higher. [ Conclusion] Polyurethane curing barn exhibits better curing performance with ~ood application prospects.展开更多
基金the financial support from the National Natural Science Foundation of China (Nos. 22125803, 22020102006 and 22307036)a project supported by the Shanghai Municipal Science and Technology Major Project (No. 2018SHZDZX03)+2 种基金the Program of Shanghai Academic/Technology Research Leader (No. 20XD1421300)China Postdoctoral Science Foundation (No. 2023M731079)the Fundamental Research Funds for the Central Universities
文摘Organic room-temperature phosphorescence(RTP)materials have garnered considerable attention in the fields of biosensing,optoelectronic devices,and anticounterfeiting because of their substantial Stokes shifts,tunable emission wavelengths,and prolonged lifetimes.These materials offer remarkable advantages for biological imaging applications by effectively reducing environmental autofluorescence and enhancing imaging resolution.Recently,host-guest systems have been employed as efficient approaches to fabricate pure-organic RTP materials for bioimaging,providing benefits such as controllable preparation and flexible modulation.Consequently,an increasing number of corresponding studies are being reported;however,a comprehensive systematic review is still lacking.Therefore,we summarize recent advances in the development of pureorganic RTP materials using host-guest systems with regard to bioimaging,including rigid matrices and sensitization.The challenge and potential of RTP for biological imaging are also proposed to promote the biomedical applications of organic RTP materials with excellent optical properties.
基金the financial support from the National Key R&D Program of China(2018YFF0215400)grants from the Gemmological Institute of the China University of Geosciences in Wuhan。
文摘Amber can emit room temperature phosphorescence(RTP)under the well-known 365 nm fluorescence ultraviolet light.This paper is devoted to the phosphorescence study of 20 pieces of amber materials from the Dominican Republic,Mexico,Baltic sea,Myanmar,and Fushun,China.The results show that amber from the same geographic origin has similar shape in phosphorescence spectra.However,the shape of the amber phosphorescence spectra varies depending on their different localities.Burmite(amber from Myanmar)and Fushun amber have a bright yellow phosphorescence with a long lifetime,while the Dominican and Mexican ones are weaker and last shorter.The irradiation of Baltic amber becomes faint or even inert.Phosphorescence spectral Gaussian fitting results suggest an emission maximum near 550 nm in most amber samples.Their phosphorescence lifetime,analyzed through the exponential function fitting,is up to 1 second in Burmite and Fushun samples,shorter in the Dominican and Mexican ones,about 0.230 s,and the shortest in Baltic amber,close to 0.151 s.These variations of phosphorescence lifetime and intensity are related to the relative geological ages of these amber.It indicated that the phosphorescence agent was probably formed during the long geological time.While the anomaly occurred in Baltic amber,the only one found in a sea secondary deposit form,it demonstrated that the terrestrial geological environment these amber preserved has prevented the phosphorescence agent to be deactivated.
基金Funded by the National Natural Science Foundation of China(No.21865017)。
文摘The reactive diluent prepared by siloxane modified Trimethylene oxide can improve the performance of the UV curing system.Therefore,1,7-bis[(3-ethyl-3-methoxyoxacylobutane)propyl]octadecylosiloxane(BEMOPOMTS)was synthesized from diethyl carbonate,trimethylopropanes,allyl bromide,and 1,1,3,3,5,5,7,7-octadecylosiloxane as the main raw materials.BEMOPOMTS can be used as reactive diluents in the field of cationic UV curing.It has good thermal stability,and the addition of BEMOPOMTS significantly improves the tensile strength and elongation at break of epoxy resin.Compared with the pure epoxy resin,adding 20%BEMOPOMTS increased the elastic modulus by 25%to 677 MPa.
基金Funded by the National Key Research and Development Program of China (No.2019YFC1906202)the Guangxi Key Research and Development Plan (Nos.Guike AA18242007-3, Guike AB19259008, and Guike AB20297014)。
文摘Internal curing agents (ICA) based on super absorbent polymer have poor alkali tolerance and reduce the early strength of concrete.An alkali tolerate internal curing agent (CAA-ICA) was designed and prepared by using sodium carboxymethyl starch (CMS) with high hydrophilicity,acrylic acid (AA) containing anionic carboxylic group and acrylamide (AM) containing non-ionic amide group as the main raw materials.The results show that the ratio of CAA-ICA alkali absorption solution is higher than that existing ICA,which solves the low water absorption ratio of the ICA in alkali environment.The water absorption ratio of CAA-ICA in saturated Ca(OH)_(2) solution is 95.8 g·g^(-1),and the alkali tolerance coefficient is 3.4.The application of CAA-ICA in cement-based materials can increase the internal relative humidity and miniaturize the pore structure.The compressive strength of mortar increases up to 12.95%at 28 d,which provids a solution to overcome the reduction of the early strength.
文摘[Objectives]This study was conducted to compare the effects of different curing processes on the characteristics of marinated beef.[Methods]Marinated beef was obtained by two curing processes:static curing and injection and vacuum tumbling curing.The effects of the two curing processes on the production rate,curing absorption rate,water content,soluble protein content,amino acid nitrogen content,texture characteristics and microstructure of the product were compared.[Results]Compared with static curing,the production rate of marinated beef increased by 10%,the curing absorption rate increased by 28%,the texture and microstructure were improved,and the water content increased,while the soluble protein content decreased.As a result,the sensory score was higher.There was no significant difference in the content of amino acid nitrogen,but it decreased compared with raw meat.To sum up,injection and vacuum tumbling curing is more conducive to the processing of marinated beef.[Conclusions]This study provides a theoretical basis for the industrial production of marinated beef,and lays a foundation for in-depth exploration of injection and vacuum tumbling curing technique of marinated beef.
基金Supported by National Key Research and Development Program of China 2023,No:2023YFC2308100.
文摘Achievement of a‘clinical cure’in chronic hepatitis B(CHB)implies sustained virological suppression and immunological control over the infection,which is the ideal treatment goal according to domestic and international CHB management guidelines.Clinical practice has shown encouraging results for specific patient cohorts using tailored treatment regimens.These regimens incorporate either nucleos(t)ide analogs,immunomodulatory agents such as pegylated interferonα,or a strategic combination of both,sequentially or concurrently administered.Despite these advancements in the clinical handling of hepatitis B,achieving a clinical cure remains elusive for a considerable subset of patients due to the number of challenges that preclude the realization of optimal treatment outcomes.These include,but are not limited to,the emergence of antiviral resistance,incomplete immune recovery,and the persistence of covalently closed circular DNA.Moreover,the variance in response to interferon therapy and the lack of definitive biomarkers for treatment cessation also contribute to the complexity of achieving a clinical cure.This article briefly overviews the current research progress and existing issues in pursuing a clinical cure for hepatitis B.
文摘Classical survival analysis assumes all subjects will experience the event of interest, but in some cases, a portion of the population may never encounter the event. These survival methods further assume independent survival times, which is not valid for honey bees, which live in nests. The study introduces a semi-parametric marginal proportional hazards mixture cure (PHMC) model with exchangeable correlation structure, using generalized estimating equations for survival data analysis. The model was tested on clustered right-censored bees survival data with a cured fraction, where two bee species were subjected to different entomopathogens to test the effect of the entomopathogens on the survival of the bee species. The Expectation-Solution algorithm is used to estimate the parameters. The study notes a weak positive association between cure statuses (ρ1=0.0007) and survival times for uncured bees (ρ2=0.0890), emphasizing their importance. The odds of being uncured for A. mellifera is higher than the odds for species M. ferruginea. The bee species, A. mellifera are more susceptible to entomopathogens icipe 7, icipe 20, and icipe 69. The Cox-Snell residuals show that the proposed semiparametric PH model generally fits the data well as compared to model that assume independent correlation structure. Thus, the semi parametric marginal proportional hazards mixture cure is parsimonious model for correlated bees survival data.
文摘Some people,mainly in the West,were taken by surprise when six Chinese warships were seen near the Red Sea in October 2023 amid the conflict in Gaza.Some Western media and politicians tried to frame China’s mission as an escalatory move in the Middle East.
文摘National food security is the backbone of any economy,and achieving food security is essential for the prosperity of a nation.During my study in China at the Institute of South-South Cooperation and Development,Peking University,from September 2022 to July 2023,I leant how China has managed to achieve food security despite its large population of around 1.4 billion and numerous other challenges by means of strategic planning,e"ective policy execution,technological advancement and global collaboration.
文摘By using HDI and TMP as the main raw materials,polyethylene glycol 400(PEG400)is used as a non-ionic hydrophilic modifier,and sodium hydroxyethyl sulfonate is used as an ionic hydrophilic modifier to synthesize a dual hydrophilic modified polyurethane curing agent.Research revealed that introducing PEG400 for hydrophilic chain segments and sodium hydroxyethyl sulfonate for hydrophilic ionic groups in the polyurethane curing agent component leads to a uniform distribution of hydrophilic components,significantly enhancing compatibility with the aqueous polyol component,and results in excellent film performance.The synthesis process and film were characterized using Fourier transform infrared spectroscopy and high-resolution scanning electron microscopy in the study.
文摘This paper examines the application of polyurethane curing technology in the construction of railway track beds,with a specific focus on its implementation in China’s rapidly developing railway infrastructure.The study begins by identifying the limitations of traditional ballasted track beds,especially under the demands of high-speed and heavyload railways.It then methodically analyzes the advantages of polyurethane-cured track beds,highlighting their improved mechanical properties,including enhanced stability and durability.The paper further explores the benefits of transitioning to prefabricated polyurethane track beds,emphasizing significant cost reductions,better construction quality,and enhanced maintainability.Through a detailed review of experimental data and practical applications,the paper demonstrates the efficacy of polyurethane track beds in various railway settings.A critical part of the research involves optimizing the structural parameters of polyurethane track beds to achieve the best balance of mechanical and damping properties.The conclusion of the paper underscores the potential of polyurethane curing technology as a transformative approach to railway track bed construction,offering a solution to the challenges posed by traditional methods and aligning with the evolving needs of modern railways.
文摘The cure kinetics of diglycidyl ether of bisphenol A (DGEBA) with hyperbranched poly (3-hydroxyphenyl) phosphate(HHPP) as the curing agent was investigated by means of non-isothermal differential scanning calorimetry (DSC) at various heating rates. The results were compared with the corresponding results by using 1,3-dihydroxybenzene(DHB) as a model compound. The results show that HHPP can enhance the cure reaction of DGEBA, resulting in the decrease of the peak temperature of the curing curve as well as the decrease of the activation energy because of the flexible --P--O-- groups in the backbone of HHPP. However, both the activation energy of the cured polymer and the peak temperature of the curing curve are increased with DHB as a curing agent. The cure kinetics of the DGEBA/HHPP system was calculated by using the isoconversional method given by Malek. It was found that the two-parameter autocatalytic model(Sestak-Berggren equation) is the most adequate one to describe the cure kinetics of the studied System at various heating rates. The obtained non-isothermal DSC curves from the experimental data show the results being accordant with those theoretically calculated.
基金supported by the Key Project of State Tobacco Monoply Administration of China(3300806156)
文摘The mechanism of carotenoid degradation and the changes in the activities of related enzymes in flue-cured tobacco at the leaf-drying stage during the bulk-curing process were studied in order to provide theoretical basis for optimization of curing technology. The effect of different rising speeds of temperature on the carotenoid degradation and the related enzymes activities at the color-fixing stage during the bulk curing process was studied by using the electric-heated fluecuring barn designed by Henan Agricultural University, China, based on curing technology with yellowing at low temperature and moderate humidity and leaf drying at moderate humidity. The results showed that the carotenoid degradation components (β-carotene, lutein, neoxanthin, and violaxthin) decreased gradually at the color-fixing stage during the bulk curing process. The carotenoid degradation components viz.,β-carotene, lutein, neoxanthin, and violaxthin at the slow heating curing (T1) were relatively higher than the rapid heating curing (T2) accounting for 10, 2, 32 and 32% respectively, but there were no differences among treatments (P〉 0.05). The effect of different conditions of curing on the activities of enzymes related to carotenoids degradation were significant. The lipoxygenase, phenylalanine ammonialyase, peroxidase, and polyphenol oxidase enzymes had a bidirectional effect on the quality of tobacco leaves and it was beneficial to form more premise matter of aroma based on the higher enzyme activities at the early leaf-drying stage. The slow heating could regulate the change in various enzymes' activities reasonably, making cell redox reaction to reach the dynamic balance and make the degradation of carotenoids adequately. Meanwhile, it could avoid the occurrence of browning reaction and provide foundation for improving the quality of tobacco and optimization of technology for bulk curing and further enhancing aroma.
基金supported by the Key Program of the National Natural Science Foundation of China (No. 19934003)the Grand Program of Natural Science Research of Anhui Education Department (No. ZD2007003-1)the Natural Science Research Program of Universities and Colleges of Anhui Province, China (Nos. KJ2008A19ZC, KJ2009B281Z, and KJ2009A053Z)
文摘La0.5Sm0.2Sr0.3MnO3/(Ag2O)x/2 (x = 0.00, 0.04, 0.08, 0.25, 0.30) samples were prepared by the solid-state reaction method, and their transport behaviors, transport mechanism, and magnetoresistance effect were studied through the measurement and fitting of p-T curves. The results show that the element Ag takes part in reaction when the doping amount is small. Ag is mainly distributed at the grain boundary of the host material and is in metallic state when the doping amount is relatively large; then the system becomes a two-phase composite. A small amount of Ag doping can apparently increase grain-boundary magnetoresistance induced by the spin-dependent scattering. The resistivity of the sample doped with 30 mol% Ag is one order of magnitude smaller than that of low-doped samples, and its magnetoresistance in the magnetic field of 0.5 T and at 300 K is strengthened apparently reaching 9.4%, which is connected not only with the improvement of the grain-boundary structure of the host material but also with the decrease of material resistivity.
基金This work was supported by the National Natural Science Foundation of China(52071137,51977071,51802040,and 21802020)the Science and Technology Innovation Program of Hunan Province(2021RC3066 and 2021RC3067)+1 种基金the Natural Science Foundation of Hunan Province(2020JJ3004 and 2020JJ4192)N.Zhang and X.Xie also acknowledge the financial support of the Fundamental Research Funds for the Central Universities.
文摘Low-temperature assembly of MXene nanosheets into three-dimensional(3D) robust aerogels addresses the crucial stability concern of the nano-building blocks during the fabrication process,which is of key importance for transforming the fascinating properties at the nanoscale into the macroscopic scale for practical applications.Herein,suitable cross-linking agents(amino-propyltriethoxysilane,Mn^(2+),Fe^(2+),Zn^(2+),and Co^(2+)) as interfacial mediators to engineer the interlayer interactions are reported to realize the graphene oxide(GO)-assisted assembly of Ti_(3)C_(2)T_(x) MXene aerogel at room temperature.This elaborate aerogel construction not only suppresses the oxidation degradation of Ti_(3)C_(2)T_(x) but also generates porous aerogels with a high Ti_(3)C_(2)T_(x) content(87 wt%) and robustness,thereby guaranteeing the functional accessibility of Ti_(3)C_(2)T_(x) nanosheets and operational reliability as integrated functional materials.In combination with a further sulfur modification,the Ti_(3)C_(2)T_(x) aerogel electrode shows promising electrochemical performances as the freestanding anode for sodium-ion storage.Even at an ultrahigh loading mass of 12.3 mg cm^(-2),a pronounced areal capacity of 1.26 mAh cm^(-2) at a current density of 0.1 A g^(-1) has been achieved,which is of practical significance.This work conceptually suggests a new way to exert the utmost surface functionalities of MXenes in 3D monolithic form and can be an inspiring scaffold to promote the application of MXenes in different areas.
基金financially supported by the National Key R@D Program of China(Grants 2016YFB0100100,2016YFA0200200)the National Natural Science Foundation of China(Grant Nos.51872283,22075279,21805273,22005297,22005298)+7 种基金the Liao Ning Revitalization Talents Program(Grant XLYC1807153)the Natural Science Foundation of Liaoning ProvinceJoint Research Fund Liaoning-Shenyang National Laboratory for Materials Science(Grant 20180510038)Dalian Innovation Support Plan for High Level Talents(2019RT09)the Dalian National Laboratory For Clean Energy(DNL),CASDNL Cooperation Fund,CAS(DNL180310,DNL180308,DNL201912,and DNL201915)DICP(DICP ZZBS201708,DICP ZZBS201802,DICP I2020032)the China Postdoctoral Science Foundation(2019M661141,2020M680995)。
文摘Synthesis and applications of three-dimensional(3 D)porous graphene frameworks(GFs)have attracted extensive interest owing to their intriguing advantages of high specific surface area,enriched porosity,excellent electrical conductivity,exceptional compressibility and processability.However,it is still challenging for economically viable,fast and scalable assembly of 3 D GFs at room-temperature.Herein,we reported a one-step scalable strategy for fast self-assembly of graphene oxide into 3 D macroscopically porous GFs,with assistance of polyoxometalates(POM)as functional cross-linker and hydrazine hydrate as reductant at room-temperature.The resulting 3 D interconnected macroporous POM-GFs uniformly decorated with ultrasmall POM nanoclusters were directly processed into binder-/additive-free film compact electrodes(1.68 g cm^(-3))with highly aligned,layer-stacked structure and electrically conductivity(622 S m-1)for high-performance supercapacitors,showing an impressive gravimetric capacitance of205 F g-1,volumetric capacitance of 334 F cm^(-3) at 1 mV s^(-1),and remarkable cycling stability with capacitance retention of 83%after 10,000 cycles,outperforming the most reported GFs.Further,the solid-state supercapacitors offered excellent gravimetric capacitance of 157 F g-1 exceptionally volumetric capacitance of 115 F cm^(-3) at 2 mV s^(-1) based on single electrode,and volumetric energy density of2.6 mWh cm^(-3).Therefore,this work will open novel opportunities to room-temperature fast assembly of 3 D porous graphene architectures for high-energy-density supercapacitors.
基金Supported by Project of Zunyi Tobacco Company[ZYJ(2014)No.201407]
文摘[ Objective] This study aimed to investigate the curing performance of polyurethane curing barn and reduce the cost of tobacco leaf flue-curing. [ Meth- odl The temperature control effect, curing effect and curing cost of polyurethane curing barn and traditional bulk curing barn were analyzed and compared. [ Re- suit] The results showed that there were no significant differences in curing performance between two types of curing barns. Horizontal temperature differences in- creased slightly as the temperature rose. Specifically, horizontal temperature differences between each layer ranged from 0.2 ~C to 0.5 ~. Both two types of curing barns exhibited uniform air distribution. Polyurethane curing barn exhibited stable vertical temperature differences. Both two types of curing barns presented good curing effects with slight differences. Polyurethane curing barn exhibited higher economic benefits, lower coal cost, lower electricity cost, lower labor cost and lon- ger service life than traditional bulk curing barn, but its construction cost was higher. [ Conclusion] Polyurethane curing barn exhibits better curing performance with ~ood application prospects.