Pre-freezing is an important stage in freeze-drying processes.For the lyophilization of a cell,freezing not only plays a role for primary dehydration,but it also determines the amount of residual(intracellular or extr...Pre-freezing is an important stage in freeze-drying processes.For the lyophilization of a cell,freezing not only plays a role for primary dehydration,but it also determines the amount of residual(intracellular or extracellular)water,which in turn can influence the solution properties and the choice of operation parameters.The freezing of human platelets in lyoprotectant solution is theoretically investigated here.A two-parameter model and an Arrhenius expression are used to describe cell membrane permeability and its temperature dependency.It is assumed that the intracellular solution is composed of four components:sodium chloride,trehalose,serum protein and water,while the extracellular solution consists of three components.Non-ideal solution behaviors are predicted using measured data.The concentration of maximally freeze-concentrated solution is estimated on the basis of an assumption of solute hydration.The impacts of lyoprotectant composition and extracellular sub-cooling on intracellular supercooling and residual water content in the cell are analyzed.The values of activation energy of hydraulic permeability at low temperatures are tested to study their impact on the critical cooling rate.As the mass fraction extracellular lyoprotectant(trehalose+bovineserum albumin)increases from 5 wt%to 20 wt%,the intracellular water content at the end of freezing does not change,but the intracellular solution undergoes much higher super-cooling degree.Increasing the mass ratio of trehalose to bovine serum albumin does not change the intracellular water content,but can mitigate intracellular super-cooling.While 0.05 mol/kg trehalose is loaded into platelet,the total quantity of residual water at the end of freezing may raise by 4.93%.The inclusion of dimethyl sulfoxide(Me2SO)in protectant may bring negative impacts to the drying stage by increasing the residual water content and lowering the drying temperature.展开更多
Mangrove ecosystems have important ecological and economic values,especially their ability to store carbon.However,in recent years,human disturbance has accelerated mangrove degradation.Among them,the emission of poll...Mangrove ecosystems have important ecological and economic values,especially their ability to store carbon.However,in recent years,human disturbance has accelerated mangrove degradation.Among them,the emission of pollutants cannot be ignored.It is of great significance for carbon emission reduction and ecological protection to study the impacts of different pollutants on mangroves and their carbon stocks.Based on the remote sensing data of coastal areas south of the Yangtze River in China's Mainland,this paper builds the ensemble learning model Random Forest(RF)and Gradient Boosting Regression(GBR)to empirically analyse the relationship between industrial wastewater,industrial sulfur dioxide(SO2),PM2.5 and mangrove forests.The results show that the pollutant concentration of meteorological normalisation is more stable.The importance of pollutants presents regional heterogeneity.The area of mangroves in different cities and the corresponding total carbon stocks show different trends with the increase or decrease of pollutants,and there is a dynamic balance between urban pollutant discharge and mangrove growth in some cities.The research in this paper provides an analysis and explanation from the perspective of machine learning to explore the relationship between mangroves and pollutants and at the same time,provides scientific suggestions for the formulation of future pollutant emission policies in different cities.展开更多
Persistent low temperatures in autumn and winter have a huge impact on crops,and greenhouses rely on solar radiation and heating equipment to meet the required indoor temperature.But the energy cost of frequent operat...Persistent low temperatures in autumn and winter have a huge impact on crops,and greenhouses rely on solar radiation and heating equipment to meet the required indoor temperature.But the energy cost of frequent operation of the actuators is exceptionally high.The relationship between greenhouse environmental control accuracy and energy consumption is one of the key issues faced in greenhouse research.In this study,a non-linear model predictive control method with an improved objective function was proposed.The improved objective function used tolerance intervals and boundary constraints to optimize the objective evaluation.The nonlinear model predictive control(NMPC)controller design was based on the wavelet neural network(WNN)data-driven model and applied the interior point method to solve the optimal solution of the objective function control,thus balancing the contradiction between energy consumption and control precision.The simulation results showed that the improved NMPC method reduced energy consumption by 21.02%and 9.54%compared with the model predictive control and regular NMPC,which proved the method achieved good results in a low-temperature environment.This research can provide an important reference for the field as it offers a more efficient approach to managing greenhouse climates,potentially leading to substantial energy savings and enhanced sustainability in agricultural practices.展开更多
With the rapid improvements in nanomaterials and imaging technology,great progresses have been made in diagnosis and treatment of diseases during the pastdecades.Fe_(3)O_(4) magnetic nanoparticles(MNPs)with good bioco...With the rapid improvements in nanomaterials and imaging technology,great progresses have been made in diagnosis and treatment of diseases during the pastdecades.Fe_(3)O_(4) magnetic nanoparticles(MNPs)with good biocompatibility and super-paramagnetic property are usually used as contrast agent for diagnosis of diseases inmagnetic resonance imaging(MRI).Currently,the combination of multiple imagingtechnologies has been considered as new tendency in diagnosis and treatment ofdiseases,which could enhance the accuracy and reliability of disease diagnosis andprovide new strategies for disease treatment.Therefore,novel contrast agents used formultifunctional imaging are urgently needed.Fe_(3)O_(4) MNPs are believed to be a potentialcandidate for construction of multifunctional platform in diagnosis and treatment ofdiseases.In recent years,there are a plethora of studies concerning the construction ofmultifunctional platform presented based on Fe_(3)O_(4) MNPs.In this review,we introducefabrication methods and modification strategies of Fe_(3)O_(4) MNPs,expecting greatimprovements for diagnosis and treatment of diseases in the future.展开更多
基金supported by the National Natural Science Foundation of China[grant number 51876185]archaeological artifact protection technology project of Zhejiang Province grant number 2017008].
文摘Pre-freezing is an important stage in freeze-drying processes.For the lyophilization of a cell,freezing not only plays a role for primary dehydration,but it also determines the amount of residual(intracellular or extracellular)water,which in turn can influence the solution properties and the choice of operation parameters.The freezing of human platelets in lyoprotectant solution is theoretically investigated here.A two-parameter model and an Arrhenius expression are used to describe cell membrane permeability and its temperature dependency.It is assumed that the intracellular solution is composed of four components:sodium chloride,trehalose,serum protein and water,while the extracellular solution consists of three components.Non-ideal solution behaviors are predicted using measured data.The concentration of maximally freeze-concentrated solution is estimated on the basis of an assumption of solute hydration.The impacts of lyoprotectant composition and extracellular sub-cooling on intracellular supercooling and residual water content in the cell are analyzed.The values of activation energy of hydraulic permeability at low temperatures are tested to study their impact on the critical cooling rate.As the mass fraction extracellular lyoprotectant(trehalose+bovineserum albumin)increases from 5 wt%to 20 wt%,the intracellular water content at the end of freezing does not change,but the intracellular solution undergoes much higher super-cooling degree.Increasing the mass ratio of trehalose to bovine serum albumin does not change the intracellular water content,but can mitigate intracellular super-cooling.While 0.05 mol/kg trehalose is loaded into platelet,the total quantity of residual water at the end of freezing may raise by 4.93%.The inclusion of dimethyl sulfoxide(Me2SO)in protectant may bring negative impacts to the drying stage by increasing the residual water content and lowering the drying temperature.
基金the Major Program of the National Fund of Philosophy and Social Science of China(Nos.21&ZD109).
文摘Mangrove ecosystems have important ecological and economic values,especially their ability to store carbon.However,in recent years,human disturbance has accelerated mangrove degradation.Among them,the emission of pollutants cannot be ignored.It is of great significance for carbon emission reduction and ecological protection to study the impacts of different pollutants on mangroves and their carbon stocks.Based on the remote sensing data of coastal areas south of the Yangtze River in China's Mainland,this paper builds the ensemble learning model Random Forest(RF)and Gradient Boosting Regression(GBR)to empirically analyse the relationship between industrial wastewater,industrial sulfur dioxide(SO2),PM2.5 and mangrove forests.The results show that the pollutant concentration of meteorological normalisation is more stable.The importance of pollutants presents regional heterogeneity.The area of mangroves in different cities and the corresponding total carbon stocks show different trends with the increase or decrease of pollutants,and there is a dynamic balance between urban pollutant discharge and mangrove growth in some cities.The research in this paper provides an analysis and explanation from the perspective of machine learning to explore the relationship between mangroves and pollutants and at the same time,provides scientific suggestions for the formulation of future pollutant emission policies in different cities.
基金supported by the National Natural Science Foundation of China(Grant.No.31901400)the Fundamental Research Funds for the Provincial Universities of Zhejiang(Grant.No.2023YW09).
文摘Persistent low temperatures in autumn and winter have a huge impact on crops,and greenhouses rely on solar radiation and heating equipment to meet the required indoor temperature.But the energy cost of frequent operation of the actuators is exceptionally high.The relationship between greenhouse environmental control accuracy and energy consumption is one of the key issues faced in greenhouse research.In this study,a non-linear model predictive control method with an improved objective function was proposed.The improved objective function used tolerance intervals and boundary constraints to optimize the objective evaluation.The nonlinear model predictive control(NMPC)controller design was based on the wavelet neural network(WNN)data-driven model and applied the interior point method to solve the optimal solution of the objective function control,thus balancing the contradiction between energy consumption and control precision.The simulation results showed that the improved NMPC method reduced energy consumption by 21.02%and 9.54%compared with the model predictive control and regular NMPC,which proved the method achieved good results in a low-temperature environment.This research can provide an important reference for the field as it offers a more efficient approach to managing greenhouse climates,potentially leading to substantial energy savings and enhanced sustainability in agricultural practices.
基金supported by the National Natural Science Foundation of China(Grant Nos.11502158,11632013 and 11802197)The support of the Shanxi Provincial Key Research and Development Project,China(Grant Nos.201803D421060,201903D421064 and 201803D421076)+1 种基金the Natural Science Foundation of Shanxi Province,China(201901D111078 and 201901D111077)the Shanxi ScholarshipCouncil of China(No.HGKY2019037)are also acknowledged withgratitude.
文摘With the rapid improvements in nanomaterials and imaging technology,great progresses have been made in diagnosis and treatment of diseases during the pastdecades.Fe_(3)O_(4) magnetic nanoparticles(MNPs)with good biocompatibility and super-paramagnetic property are usually used as contrast agent for diagnosis of diseases inmagnetic resonance imaging(MRI).Currently,the combination of multiple imagingtechnologies has been considered as new tendency in diagnosis and treatment ofdiseases,which could enhance the accuracy and reliability of disease diagnosis andprovide new strategies for disease treatment.Therefore,novel contrast agents used formultifunctional imaging are urgently needed.Fe_(3)O_(4) MNPs are believed to be a potentialcandidate for construction of multifunctional platform in diagnosis and treatment ofdiseases.In recent years,there are a plethora of studies concerning the construction ofmultifunctional platform presented based on Fe_(3)O_(4) MNPs.In this review,we introducefabrication methods and modification strategies of Fe_(3)O_(4) MNPs,expecting greatimprovements for diagnosis and treatment of diseases in the future.
