Lipid droplets serve as primary storage organelles for neutral lipids in neurons,glial cells,and other cells in the nervous system.Lipid droplet formation begins with the synthesis of neutral lipids in the endoplasmic...Lipid droplets serve as primary storage organelles for neutral lipids in neurons,glial cells,and other cells in the nervous system.Lipid droplet formation begins with the synthesis of neutral lipids in the endoplasmic reticulum.Previously,lipid droplets were recognized for their role in maintaining lipid metabolism and energy homeostasis;however,recent research has shown that lipid droplets are highly adaptive organelles with diverse functions in the nervous system.In addition to their role in regulating cell metabolism,lipid droplets play a protective role in various cellular stress responses.Furthermore,lipid droplets exhibit specific functions in neurons and glial cells.Dysregulation of lipid droplet formation leads to cellular dysfunction,metabolic abnormalities,and nervous system diseases.This review aims to provide an overview of the role of lipid droplets in the nervous system,covering topics such as biogenesis,cellular specificity,and functions.Additionally,it will explore the association between lipid droplets and neurodegenerative disorders.Understanding the involvement of lipid droplets in cell metabolic homeostasis related to the nervous system is crucial to determine the underlying causes and in exploring potential therapeutic approaches for these diseases.展开更多
The controllable transfer of droplets on the surface of objects has a wide application prospect in the fields of microfluidic devices,fog collection and so on.The Leidenfrost effect can be utilized to significantly re...The controllable transfer of droplets on the surface of objects has a wide application prospect in the fields of microfluidic devices,fog collection and so on.The Leidenfrost effect can be utilized to significantly reduce motion resistance.However,the use of 3D structures limits the widespread application of self-propulsion based on Leidenfrost droplets in microelectromechanical system.To manipulate Leidenfrost droplets,it is necessary to create 2D or quasi-2D geometries.In this study,femtosecond laser is applied to fabricate a surface with periodic hydrophobicity gradient(SPHG),enabling directional self-propulsion of Leidenfrost droplets.Flow field analysis within the Leidenfrost droplets reveals that the vapor layer between the droplets and the hot surface can be modulated by the SPHG,resulting in directional propulsion of the inner gas.The viscous force between the gas and liquid then drives the droplet to move.展开更多
In fog, visibility is reduced. This reduction in visibility is measured by the meteorological optical range (MOR), which is important for studying human perception and various sensors in foggy conditions. The Cerema P...In fog, visibility is reduced. This reduction in visibility is measured by the meteorological optical range (MOR), which is important for studying human perception and various sensors in foggy conditions. The Cerema PAVIN Fog & Rain platform is capable of producing calibrated fog in order to better analyses it and understand its consequences. The problem is that the droplets produced by the platform are not large enough to resemble real fog. This can have a major impact on measurements since the interaction between electromagnetic waves and fog depends on the wavelength and diameter of the droplets. To remedy this, Cerema is building a new platform with new equipment capable of generating fog. This study analyses different nozzles and associated usage parameters such as the type of water used and the pressure used. The aim is to select the best nozzle with the associated parameters for producing large-diameter droplets and therefore more realistic fog.展开更多
The use of‘Electrostatic tweezers'is a promising tool for droplet manipulation,but it faces many limitations in manipulating droplets on superhydrophobic surfaces.Here,we achieve noncontact and multifunctional dr...The use of‘Electrostatic tweezers'is a promising tool for droplet manipulation,but it faces many limitations in manipulating droplets on superhydrophobic surfaces.Here,we achieve noncontact and multifunctional droplet manipulation on Nepenthes-inspired lubricated slippery surfaces via triboelectric electrostatic tweezers(TETs).The TET manipulation of droplets on a slippery surface has many advantages over electrostatic droplet manipulation on a superhydrophobic surface.The electrostatic field induces the redistribution of the charges inside the neutral droplet,which causes the triboelectric charged rod to drive the droplet to move forward under the electrostatic force.Positively or negatively charged droplets can also be driven by TET based on electrostatic attraction and repulsion.TET enables us to manipulate droplets under diverse conditions,including anti-gravity climb,suspended droplets,corrosive liquids,low-surface-tension liquids(e.g.ethanol with a surface tension of 22.3 mN·m^(-1)),different droplet volumes(from 100 nl to 0.5 ml),passing through narrow slits,sliding over damaged areas,on various solid substrates,and even droplets in an enclosed system.Various droplet-related applications,such as motion guidance,motion switching,droplet-based microreactions,surface cleaning,surface defogging,liquid sorting,and cell labeling,can be easily achieved with TETs.展开更多
The effect of the inlet gas pressure,supplementary gas pressure and nozzle channel dispersion angle on the pre-breakup behavior of Ti-6Al-4V(TC4)discontinuous droplets during EIGA was investigated by combining numeric...The effect of the inlet gas pressure,supplementary gas pressure and nozzle channel dispersion angle on the pre-breakup behavior of Ti-6Al-4V(TC4)discontinuous droplets during EIGA was investigated by combining numerical simulation with experiments.The results show that the axial velocity at the recirculation zone before the stagnation location was first increased and decreased then increased significantly after the peak value,while the pressure of the recirculation zone increased with the increase in inlet pressure.With the supplementary pressure increasing,the velocity magnitude and range of the recirculation zone gradually decreased.As the dispersion angle of the nozzle channel increased,the pre-breakup efficiency of droplets gradually decreased,but the adhesion phenomenon of droplets on the inner wall surface of the nozzle channel(IWSNC)gradually weakened.Under the inlet pressure of 4 MPa,a supplementary pressure of 0.05 MPa,and the dispersion angle of 15°,the uniform and spherical TC4 powders with diameter of 70μm were prepared,which was consistent with the simulation results.The optimized process parameters is a balance between the size of the pre-atomized particles and the back-spraying and bonding phenomenons of droplets.展开更多
Lipid droplets(LDs)participate in many physiological processes,the abnormality of which will cause chronic diseases and pathologies such as diabetes and obesity.It is crucial to monitor the distribution of LDs at high...Lipid droplets(LDs)participate in many physiological processes,the abnormality of which will cause chronic diseases and pathologies such as diabetes and obesity.It is crucial to monitor the distribution of LDs at high spatial resolution and large depth.Herein,we carried three-photon imaging of LDs in fat liver.Owing to the large three-photon absorption cross-section of the luminogen named NAP-CF_(3)(1:67×10^(-79) cm^(6) s^(2)),three-photon fluorescence fat liver imaging reached the largest depth of 80μm.Fat liver diagnosis was successfully carried out with excellent performance,providing great potential for LDs-associated pathologies research.展开更多
The paper presents the experimental research findings for the patterns of collisions of water droplets with pressed tableted samples used as substrates and with small particles of a pyrolyzing solid fuel.Brown coal sa...The paper presents the experimental research findings for the patterns of collisions of water droplets with pressed tableted samples used as substrates and with small particles of a pyrolyzing solid fuel.Brown coal samples were used.Droplet-substrate interactions were studied when varying the droplet diameter in the range from 1 to 4 mm and velocity from 0.5 to 4 m/s.That corresponded to the Weber number range of 7-830.The coal tablet surface temperature was varied from 20 to 700℃.In the interactions of water droplets(0.7-1.5 mm in diameter,pre-collision velocity from 1 to 3 m/s)with coal particles(with a size of 0.2-1 mm,pre-collision velocity 0.7-2 m/s),the temperature of the latter was varied in the range of 330-480℃.The following regimes of the interaction of droplets with solid particles during chemical reactions and phase transformations were distinguished:spreading/agglomeration and break-up/separation.Differences in the characteristics of the interaction of water droplets with coal particles at varying temperatures were identified.Droplet-particle interaction regime maps for B(We),We(Oh)and We(Ca)were constructed.The collision regime boundaries were described using fitted curves that can be utilized to develop the existing mathematical models of droplet-particle collisions in gas.It was established that the gaseous volatile production in coal pyrolysis has a modest effect on the regimes and characteristics of the droplet destruction in the temperature range under consideration(20-700℃).展开更多
In order to study the successive deposition and solidification processes of uniform alloy droplets during the drop-on-demand three dimensional(3D) printing method,based on the volume of fluid(VOF) method,a 3D nume...In order to study the successive deposition and solidification processes of uniform alloy droplets during the drop-on-demand three dimensional(3D) printing method,based on the volume of fluid(VOF) method,a 3D numerical model was employed.In this model,the 7075 alloy with larger temperature range for phase change was used.The simulation results show that the successive deposition and solidification processes of uniform 7075 alloy droplets can be well characterized by this model.Simulated droplets shapes agree well with SEM images under the same condition.The effects of deposition and solidification of droplets result in vertical and L-shaped ridges on the surface of droplets,and tips of dendrites appear near the overlap of droplets due to rapid solidification.展开更多
The droplet velocity and diameter significantly affect both the spatial drift loss and the interfacial deposition behaviors, thus determining the ultimate utilization efficiency during pesticide spraying.Investigating...The droplet velocity and diameter significantly affect both the spatial drift loss and the interfacial deposition behaviors, thus determining the ultimate utilization efficiency during pesticide spraying.Investigating the spatial velocity and diameter evolutions can reveal the mechanism of drift loss and guide to design regulation strategy. Here, we explored the spatial velocity distribution of droplets after leaving the nozzle by particle image velocimetry technology and particle tracking model, considering that the effect of nozzle configuration and the air velocity. It shows that all droplets decelerate rapidly with the velocity attenuation ratio ranging from 50% to 80% within the region of 200 mm below the nozzle.The spatial velocity evolution differences between droplets in crossflow are determined by the competition of vertical drag force and net gravity, and the drag force sharply increases as the droplet diameter decreases, especially for that smaller than 150 μm. Based on the spatial evolution differences of the droplet velocity and diameter, a functional adjuvant was added to the liquid for improving the diameter distribution. And the drift loss was significantly reduced due to the reduction of the proportion of easily drifting droplets.展开更多
Based on the method of discrete phase, the law of droplets’ deposition in the last stage stationary blade of a supercritical 600 MW Steam Turbine is simulated in the first place of this paper by using the Wet-steam m...Based on the method of discrete phase, the law of droplets’ deposition in the last stage stationary blade of a supercritical 600 MW Steam Turbine is simulated in the first place of this paper by using the Wet-steam model in commercial software FLUENT, where the influence of inlet angle of water droplets of the stationary blades is also considered. Through the calculation, the relationship between the deposition and the diameter of water droplets is revealed. Then, the amount of droplets deposition in the suction and pressure surface is derived. The result is compared with experimental data and it proves that the numerical simulation result obtained in this paper is reasonable. Finally, a formula of the relationship between the diameter of water droplets and the inlet angle is fit, which could be used for approximate calculation in the engineering applications.展开更多
In order to clarify the charging characteristics of suspension droplets in ion flow field under different temperatures and humidity,the effective charging factor used to characterize the charging characteristics of su...In order to clarify the charging characteristics of suspension droplets in ion flow field under different temperatures and humidity,the effective charging factor used to characterize the charging characteristics of suspension droplets is introduced in this paper,and a calculation method of charging factor is proposed based on the upstream finite element method(FEM).Then,the charging factor under different temperatures and humidity is calculated,and the analytic expression of the charging factor considering the influence of temperature and humidity is obtained by fitting the calculation results.The influence of suspension droplets on the ion flow field is analyzed.The results show that the charging factor is small and increases little with the relative humidity when the relative humidity is less than 60%,and the charging factor is large and increases rapidly with the relative humidity when the relative humidity is more than 60%.At the same relative humidity,the charging factor increases linearly with the temperature.The influence of charged suspension droplets on the ion flow field can be ignored when the relative humidity is less than 60%and must be considered under high temperature and humidity.The calculation method and analytic expression of the charging factor proposed in this paper can be used to model of ion flow field considering the influence of temperature and humidity and provide technical support for the construction of HVDC transmission lines across high temperature and humidity.展开更多
Aim: In order to reveal the histochemical alteration that might occur during the processes of the spermatogenic dis-ruption induced by testicular capsulotomy, the location and alteration of lipid droplets in the semin...Aim: In order to reveal the histochemical alteration that might occur during the processes of the spermatogenic dis-ruption induced by testicular capsulotomy, the location and alteration of lipid droplets in the seminiferous tubules wereobserved in the present study. Methods: Osmium tetroxide was used to demonstrate the lipid droplets in the semi-niferous tubules of capsulotomized and sham-operated control testes. Results: In the seminiferous tubules of thesham-operated rat testes, many small lipid droplets were located close to the basement membrane of the seminiferoustubules. But for the capsulotomized testes, the lipid droplets in the seminiferous tubules had increased in size and num-ber, with many lipid droplets migrated towards the lumen of the tubules. Conclusion: The results indicated that aprogressive fatty degeneration occurred in the seminiferous tubules after testicular capsulotomy.展开更多
Previously regarded as simple fat storage particles,new evidence suggests thatlipid droplets(LDs)are dynamic and functional organelles involved in keycellular processes such as membrane biosynthesis,lipid metabolism,c...Previously regarded as simple fat storage particles,new evidence suggests thatlipid droplets(LDs)are dynamic and functional organelles involved in keycellular processes such as membrane biosynthesis,lipid metabolism,cellsignalling and inflammation.Indeed,an increased LD content is one of the mostapparent features resulting from lipid metabolism reprogramming necessary tosupport the basic functions of cancer cells.LDs have been associated to differentcellular processes involved in cancer progression and aggressiveness,such astumorigenicity,invasion and metastasis,as well as chemoresistance.Interestingly,all of these processes are controlled by a subpopulation of highly aggressivetumoral cells named cancer stem cells(CSCs),suggesting that LDs may befundamental elements for stemness in cancer.Considering the key role of CSCs onchemoresistance and disease relapse,main factors of therapy failure,the design ofnovel therapeutic approaches targeting these cells may be the only chance forlong-term survival in cancer patients.In this sense,their biology and functionalproperties render LDs excellent candidates for target discovery and design ofcombined therapeutic strategies.In this review,we summarise the currentknowledge identifying LDs and CSCs as main contributors to cancer aggressiveness,metastasis and chemoresistance.展开更多
The Annona genus is a member of Annonaceae,one of the largest families of plants across tropical and subtropical regions.This family has been used in several ethnomedicinal practices to treat a multitude of human dise...The Annona genus is a member of Annonaceae,one of the largest families of plants across tropical and subtropical regions.This family has been used in several ethnomedicinal practices to treat a multitude of human diseases.However,the molecular mechanism underlying its effect on the lipid droplet formation and on the expression of adipogenic markers of this plant remain to be investigated.In this study,we examined whether the extracts from the aerial part of Annona montana affect in vitro differentiation of preadipocytes.For our investigations,both mouse embryo fibroblast 3T3-L1 and normal human primary subcutaneous preadipocytes were incubated with Annona montana extracts(-and its subfractions-)and then analyzed on preadipocyte differentiation,lipid content,lipid droplet size and number,the expression of adipogenic-specific transcriptional factors,as well as cell survival.From our examinations,we found the Annona montana ethyl acetate extract to exhibit a potent inhibitory effect on adipogenesis,without affecting cell survival,in a dose-dependent manner.Such inhibitory effects included a significant decrease in the accumulation of lipid content by both a dramatic reduction of size and number of lipid droplets.This extract strongly attenuated the expression of PPARγand HMGB2.It also inhibited the expression of CEBPα,FAS,and Akt without influencing Erk1/2 activities.Our findings suggest that specifically,the Annona montana ethyl acetate extract has a prominent inhibitory effect in cellular pathways of adipocyte differentiation by modulating specific gene expression,which is known to perform a pivotal role during adipogenesis.展开更多
In this article, a theoretical model for predicting the equilibrium morphology of gas–liquid Janus droplets was built. Based on this model, the effects of bubble radius and volume ratio on morphology change was syste...In this article, a theoretical model for predicting the equilibrium morphology of gas–liquid Janus droplets was built. Based on this model, the effects of bubble radius and volume ratio on morphology change was systematically studied. The increase of bubble radius causes the two parts(bubble and oil drop) in Janus droplets tend to merge while the impact of volume ratio is complicated. When volume ratio increases, these two parts firstly tend to merge, then gradually separate. The accuracy of this model was verified by experimental results.展开更多
Vortexing limestone injection into furnace combined with calcium lime hydration in the downstream is the most promising technology for controlling SO 2 emission. Particle imaging velocimetry (PIV) is used to measure ...Vortexing limestone injection into furnace combined with calcium lime hydration in the downstream is the most promising technology for controlling SO 2 emission. Particle imaging velocimetry (PIV) is used to measure the gas liquid solid three phase flow field in a reactor. By image processing based on newly developed software, the number concentrations of sorbent particles and water droplets are presented. The measuring results are very helpful for better understanding the desulfurization mechanism and optimizing configurational and operational parameters in the hydration reactor.展开更多
The maximum entropy principle(MEP) is one of the first methods which have been used to predict droplet size and velocity distributions of liquid sprays. This method needs a mean droplets diameter as an input to predic...The maximum entropy principle(MEP) is one of the first methods which have been used to predict droplet size and velocity distributions of liquid sprays. This method needs a mean droplets diameter as an input to predict the droplet size distribution. This paper presents a new sub-model based on the deterministic aspects of liquid atomization process independent of the experimental data to provide the mean droplets diameter for using in the maximum entropy formulation(MEF). For this purpose, a theoretical model based on the approach of energy conservation law entitled energy-based model(EBM) is presented. Based on this approach, atomization occurs due to the kinetic energy loss. Prediction of the combined model(MEF/EBM) is in good agreement with the available experimental data. The energy-based model can be used as a fast and reliable enough model to obtain a good estimation of the mean droplets diameter of a spray and the combined model(MEF/EBM) can be used to well predict the droplet size distribution at the primary breakup.展开更多
This paper presents a molecular dynamics simulation of the behaviours of non-polar droplets merging and also the fluid molecules interacting with a hydrophobic surface. Such behaviours and transport phenomena are popu...This paper presents a molecular dynamics simulation of the behaviours of non-polar droplets merging and also the fluid molecules interacting with a hydrophobic surface. Such behaviours and transport phenomena are popular in general microchannel flow boiling and two-phase flow. The droplets are assumed to be composed of Lennards-Jones type molecules. Periodic boundary conditions are applied in three coordinate directions of a 3-D system, where there exist two liquid droplets and their vapour. The two droplets merge when they come within the prescribed small distance. The merging of two droplets apart from each other at different initial distances is tested and the possible larger (or critical) non-dimensional distance, in which droplets merging can occur, is discussed. The evolution of the merging process is simulated numerically by employing the Molecular Dynamics (MD) method. For interactions with hydrophobic solid wall, a system with fluid confined between two walls is used to study the wetting phenomena of fluid and solid wall. The results are compared with those of hydrophilic wall to show the unique characteristics of hydrophobic interactions by microscopic methods.展开更多
Three-phase line tensions may become crucial in the adhesion of miero-nano or small droplets on solid planes. In this paper we study for the first time the nonlinear effects in adhesion spanning the full range of phys...Three-phase line tensions may become crucial in the adhesion of miero-nano or small droplets on solid planes. In this paper we study for the first time the nonlinear effects in adhesion spanning the full range of physically possible parameters of surface tension, line tension, and droplet size. It is shown that the nonlinear adhesion solution spaces can be characterized into four regions. Within each region the adhesion behaves essentially the same. Especially, inside the characteristic regions with violent nonlinearities, the co-existence of multiple adhesion states for given materials is disclosed. Besides, two common fixed points in the solution space are revealed. These new results are consistent with numerical analysis and experimental observations reported in the literatures.展开更多
The impact of droplets on the liquid film is widely involved in industrial and agricultural fields.In recent years,plenty of works are limited to dry walls or stationary liquid films,and the research of multi-droplet ...The impact of droplets on the liquid film is widely involved in industrial and agricultural fields.In recent years,plenty of works are limited to dry walls or stationary liquid films,and the research of multi-droplet impact dynamic films is not sufficient.Based on this,this paper employs a coupled level set and volume of fluid(CLSVOF) method to numerically simulate two-droplet impingement on a dynamic liquid film.In our work,the dynamic film thickness,horizontal central distance between the droplets,droplets’ initial impact speed,and simultaneously the flow velocity of the moving film are analyzed.The evolution phenomenon and mechanism caused by the collision are analyzed in detail.We find that within a certain period of time,the droplet spacing does not affect the peripheral crown height;when the droplet spacing decreases or the initial impact velocity increases,the height of the peripheral crown increases at the beginning,and then,because the crown splashed under Rayleigh-Plateau instability,this results in the reduction of the crown height.At the same time,it is found that when the initial impact velocity increases,the angle between the upstream peripheral jet and the dynamic film becomes larger.The more obvious the horizontal movement characteristics,the more restrained the crown height;the spread length increases with the increase of the dynamic film speed,droplet spacing and the initial impact velocity.When the liquid film is thicker,more fluid enters the crown,due to the crown being unstable,the surface tension is not enough to overcome the weight of the rim at the end of the crown,resulting in droplets falling off.展开更多
基金funded by Basic Research Program of Shanghai,No.20JC1412200(to JW)the National Key Research and Development Program of China,No.2020YFA0113000(to RCZ)。
文摘Lipid droplets serve as primary storage organelles for neutral lipids in neurons,glial cells,and other cells in the nervous system.Lipid droplet formation begins with the synthesis of neutral lipids in the endoplasmic reticulum.Previously,lipid droplets were recognized for their role in maintaining lipid metabolism and energy homeostasis;however,recent research has shown that lipid droplets are highly adaptive organelles with diverse functions in the nervous system.In addition to their role in regulating cell metabolism,lipid droplets play a protective role in various cellular stress responses.Furthermore,lipid droplets exhibit specific functions in neurons and glial cells.Dysregulation of lipid droplet formation leads to cellular dysfunction,metabolic abnormalities,and nervous system diseases.This review aims to provide an overview of the role of lipid droplets in the nervous system,covering topics such as biogenesis,cellular specificity,and functions.Additionally,it will explore the association between lipid droplets and neurodegenerative disorders.Understanding the involvement of lipid droplets in cell metabolic homeostasis related to the nervous system is crucial to determine the underlying causes and in exploring potential therapeutic approaches for these diseases.
基金supported by the Beijing Municipal Natural Science Foundation(JQ20015)National Key Research and Development Program of China(No.2022YFB4601300)+3 种基金the National Science Fund for Distinguished Young Scholars(No.52325505)the National Natural Science Foundation of China(NSFC)(No.52075041)the Joint Funds of the National Natural Science Foundation of China(Grant No.U2037205)the Open Project Program of Wuhan National Laboratory for Optoelectronics(No2021WNLOKF016)。
文摘The controllable transfer of droplets on the surface of objects has a wide application prospect in the fields of microfluidic devices,fog collection and so on.The Leidenfrost effect can be utilized to significantly reduce motion resistance.However,the use of 3D structures limits the widespread application of self-propulsion based on Leidenfrost droplets in microelectromechanical system.To manipulate Leidenfrost droplets,it is necessary to create 2D or quasi-2D geometries.In this study,femtosecond laser is applied to fabricate a surface with periodic hydrophobicity gradient(SPHG),enabling directional self-propulsion of Leidenfrost droplets.Flow field analysis within the Leidenfrost droplets reveals that the vapor layer between the droplets and the hot surface can be modulated by the SPHG,resulting in directional propulsion of the inner gas.The viscous force between the gas and liquid then drives the droplet to move.
文摘In fog, visibility is reduced. This reduction in visibility is measured by the meteorological optical range (MOR), which is important for studying human perception and various sensors in foggy conditions. The Cerema PAVIN Fog & Rain platform is capable of producing calibrated fog in order to better analyses it and understand its consequences. The problem is that the droplets produced by the platform are not large enough to resemble real fog. This can have a major impact on measurements since the interaction between electromagnetic waves and fog depends on the wavelength and diameter of the droplets. To remedy this, Cerema is building a new platform with new equipment capable of generating fog. This study analyses different nozzles and associated usage parameters such as the type of water used and the pressure used. The aim is to select the best nozzle with the associated parameters for producing large-diameter droplets and therefore more realistic fog.
基金supported by the USTC Research Funds of the Double First-Class Initiative(Nos.YD2090002013,YD234000009)the National Natural Science Foundation of China(Nos.61927814,62325507,52122511,U20A20290,62005262)。
文摘The use of‘Electrostatic tweezers'is a promising tool for droplet manipulation,but it faces many limitations in manipulating droplets on superhydrophobic surfaces.Here,we achieve noncontact and multifunctional droplet manipulation on Nepenthes-inspired lubricated slippery surfaces via triboelectric electrostatic tweezers(TETs).The TET manipulation of droplets on a slippery surface has many advantages over electrostatic droplet manipulation on a superhydrophobic surface.The electrostatic field induces the redistribution of the charges inside the neutral droplet,which causes the triboelectric charged rod to drive the droplet to move forward under the electrostatic force.Positively or negatively charged droplets can also be driven by TET based on electrostatic attraction and repulsion.TET enables us to manipulate droplets under diverse conditions,including anti-gravity climb,suspended droplets,corrosive liquids,low-surface-tension liquids(e.g.ethanol with a surface tension of 22.3 mN·m^(-1)),different droplet volumes(from 100 nl to 0.5 ml),passing through narrow slits,sliding over damaged areas,on various solid substrates,and even droplets in an enclosed system.Various droplet-related applications,such as motion guidance,motion switching,droplet-based microreactions,surface cleaning,surface defogging,liquid sorting,and cell labeling,can be easily achieved with TETs.
基金Funded by the National Natural Science Foundation of China(No.51627805)the Natural Scienceof Guangdong Province,China(No.2015A030312003)the Science and Technology Research Project of Guangdong Province,China(No.2014B010129003)。
文摘The effect of the inlet gas pressure,supplementary gas pressure and nozzle channel dispersion angle on the pre-breakup behavior of Ti-6Al-4V(TC4)discontinuous droplets during EIGA was investigated by combining numerical simulation with experiments.The results show that the axial velocity at the recirculation zone before the stagnation location was first increased and decreased then increased significantly after the peak value,while the pressure of the recirculation zone increased with the increase in inlet pressure.With the supplementary pressure increasing,the velocity magnitude and range of the recirculation zone gradually decreased.As the dispersion angle of the nozzle channel increased,the pre-breakup efficiency of droplets gradually decreased,but the adhesion phenomenon of droplets on the inner wall surface of the nozzle channel(IWSNC)gradually weakened.Under the inlet pressure of 4 MPa,a supplementary pressure of 0.05 MPa,and the dispersion angle of 15°,the uniform and spherical TC4 powders with diameter of 70μm were prepared,which was consistent with the simulation results.The optimized process parameters is a balance between the size of the pre-atomized particles and the back-spraying and bonding phenomenons of droplets.
基金supported by National Natural Science Foundation of China (61975172,82001874,62105184)the Guangdong Basic and Applied Basic Research Foundation (2020A1515110578).
文摘Lipid droplets(LDs)participate in many physiological processes,the abnormality of which will cause chronic diseases and pathologies such as diabetes and obesity.It is crucial to monitor the distribution of LDs at high spatial resolution and large depth.Herein,we carried three-photon imaging of LDs in fat liver.Owing to the large three-photon absorption cross-section of the luminogen named NAP-CF_(3)(1:67×10^(-79) cm^(6) s^(2)),three-photon fluorescence fat liver imaging reached the largest depth of 80μm.Fat liver diagnosis was successfully carried out with excellent performance,providing great potential for LDs-associated pathologies research.
基金supported by the Russian Science Foundation (project 18-71-10002-π,https://rscf.ru/en/project/21-71-03001/)。
文摘The paper presents the experimental research findings for the patterns of collisions of water droplets with pressed tableted samples used as substrates and with small particles of a pyrolyzing solid fuel.Brown coal samples were used.Droplet-substrate interactions were studied when varying the droplet diameter in the range from 1 to 4 mm and velocity from 0.5 to 4 m/s.That corresponded to the Weber number range of 7-830.The coal tablet surface temperature was varied from 20 to 700℃.In the interactions of water droplets(0.7-1.5 mm in diameter,pre-collision velocity from 1 to 3 m/s)with coal particles(with a size of 0.2-1 mm,pre-collision velocity 0.7-2 m/s),the temperature of the latter was varied in the range of 330-480℃.The following regimes of the interaction of droplets with solid particles during chemical reactions and phase transformations were distinguished:spreading/agglomeration and break-up/separation.Differences in the characteristics of the interaction of water droplets with coal particles at varying temperatures were identified.Droplet-particle interaction regime maps for B(We),We(Oh)and We(Ca)were constructed.The collision regime boundaries were described using fitted curves that can be utilized to develop the existing mathematical models of droplet-particle collisions in gas.It was established that the gaseous volatile production in coal pyrolysis has a modest effect on the regimes and characteristics of the droplet destruction in the temperature range under consideration(20-700℃).
基金Projects (51005186,51221001) supported by the National Natural Science Foundation of ChinaProject (85-TZ-2013) supported by the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),ChinaProject (20126102110022) supported by the Doctoral Fund of Ministry of Education of China
文摘In order to study the successive deposition and solidification processes of uniform alloy droplets during the drop-on-demand three dimensional(3D) printing method,based on the volume of fluid(VOF) method,a 3D numerical model was employed.In this model,the 7075 alloy with larger temperature range for phase change was used.The simulation results show that the successive deposition and solidification processes of uniform 7075 alloy droplets can be well characterized by this model.Simulated droplets shapes agree well with SEM images under the same condition.The effects of deposition and solidification of droplets result in vertical and L-shaped ridges on the surface of droplets,and tips of dendrites appear near the overlap of droplets due to rapid solidification.
基金This work was financially supported by the National Key Research and Development Program of China(2017YFD0200304).
文摘The droplet velocity and diameter significantly affect both the spatial drift loss and the interfacial deposition behaviors, thus determining the ultimate utilization efficiency during pesticide spraying.Investigating the spatial velocity and diameter evolutions can reveal the mechanism of drift loss and guide to design regulation strategy. Here, we explored the spatial velocity distribution of droplets after leaving the nozzle by particle image velocimetry technology and particle tracking model, considering that the effect of nozzle configuration and the air velocity. It shows that all droplets decelerate rapidly with the velocity attenuation ratio ranging from 50% to 80% within the region of 200 mm below the nozzle.The spatial velocity evolution differences between droplets in crossflow are determined by the competition of vertical drag force and net gravity, and the drag force sharply increases as the droplet diameter decreases, especially for that smaller than 150 μm. Based on the spatial evolution differences of the droplet velocity and diameter, a functional adjuvant was added to the liquid for improving the diameter distribution. And the drift loss was significantly reduced due to the reduction of the proportion of easily drifting droplets.
文摘Based on the method of discrete phase, the law of droplets’ deposition in the last stage stationary blade of a supercritical 600 MW Steam Turbine is simulated in the first place of this paper by using the Wet-steam model in commercial software FLUENT, where the influence of inlet angle of water droplets of the stationary blades is also considered. Through the calculation, the relationship between the deposition and the diameter of water droplets is revealed. Then, the amount of droplets deposition in the suction and pressure surface is derived. The result is compared with experimental data and it proves that the numerical simulation result obtained in this paper is reasonable. Finally, a formula of the relationship between the diameter of water droplets and the inlet angle is fit, which could be used for approximate calculation in the engineering applications.
基金supported by National Natural Science Foundation of China(No.52077074)。
文摘In order to clarify the charging characteristics of suspension droplets in ion flow field under different temperatures and humidity,the effective charging factor used to characterize the charging characteristics of suspension droplets is introduced in this paper,and a calculation method of charging factor is proposed based on the upstream finite element method(FEM).Then,the charging factor under different temperatures and humidity is calculated,and the analytic expression of the charging factor considering the influence of temperature and humidity is obtained by fitting the calculation results.The influence of suspension droplets on the ion flow field is analyzed.The results show that the charging factor is small and increases little with the relative humidity when the relative humidity is less than 60%,and the charging factor is large and increases rapidly with the relative humidity when the relative humidity is more than 60%.At the same relative humidity,the charging factor increases linearly with the temperature.The influence of charged suspension droplets on the ion flow field can be ignored when the relative humidity is less than 60%and must be considered under high temperature and humidity.The calculation method and analytic expression of the charging factor proposed in this paper can be used to model of ion flow field considering the influence of temperature and humidity and provide technical support for the construction of HVDC transmission lines across high temperature and humidity.
文摘Aim: In order to reveal the histochemical alteration that might occur during the processes of the spermatogenic dis-ruption induced by testicular capsulotomy, the location and alteration of lipid droplets in the seminiferous tubules wereobserved in the present study. Methods: Osmium tetroxide was used to demonstrate the lipid droplets in the semi-niferous tubules of capsulotomized and sham-operated control testes. Results: In the seminiferous tubules of thesham-operated rat testes, many small lipid droplets were located close to the basement membrane of the seminiferoustubules. But for the capsulotomized testes, the lipid droplets in the seminiferous tubules had increased in size and num-ber, with many lipid droplets migrated towards the lumen of the tubules. Conclusion: The results indicated that aprogressive fatty degeneration occurred in the seminiferous tubules after testicular capsulotomy.
基金Miguel Servet Fellowship,No.CP16/00121FIS(Fondo Investigaciones Sanitarias)grants,No.PI17/00082 and No.PI20/00942,all from Instituto de Salud Carlos Ⅲ and Cofinanced by European Funds(FSE:“El FSE invierte en tu futuro”and FEDER:“Una manera de hacer Europa,”respectively)and the Worldwide Cancer Research Charity together with Fundación Científica Asociación Española contra el Cáncer(FCAECC),No.19-0250.
文摘Previously regarded as simple fat storage particles,new evidence suggests thatlipid droplets(LDs)are dynamic and functional organelles involved in keycellular processes such as membrane biosynthesis,lipid metabolism,cellsignalling and inflammation.Indeed,an increased LD content is one of the mostapparent features resulting from lipid metabolism reprogramming necessary tosupport the basic functions of cancer cells.LDs have been associated to differentcellular processes involved in cancer progression and aggressiveness,such astumorigenicity,invasion and metastasis,as well as chemoresistance.Interestingly,all of these processes are controlled by a subpopulation of highly aggressivetumoral cells named cancer stem cells(CSCs),suggesting that LDs may befundamental elements for stemness in cancer.Considering the key role of CSCs onchemoresistance and disease relapse,main factors of therapy failure,the design ofnovel therapeutic approaches targeting these cells may be the only chance forlong-term survival in cancer patients.In this sense,their biology and functionalproperties render LDs excellent candidates for target discovery and design ofcombined therapeutic strategies.In this review,we summarise the currentknowledge identifying LDs and CSCs as main contributors to cancer aggressiveness,metastasis and chemoresistance.
基金supported by the National Institutes of Health Grant SC1DK084343the U.S.Department of Defense Grant W911NF-13-0167(to MAB).
文摘The Annona genus is a member of Annonaceae,one of the largest families of plants across tropical and subtropical regions.This family has been used in several ethnomedicinal practices to treat a multitude of human diseases.However,the molecular mechanism underlying its effect on the lipid droplet formation and on the expression of adipogenic markers of this plant remain to be investigated.In this study,we examined whether the extracts from the aerial part of Annona montana affect in vitro differentiation of preadipocytes.For our investigations,both mouse embryo fibroblast 3T3-L1 and normal human primary subcutaneous preadipocytes were incubated with Annona montana extracts(-and its subfractions-)and then analyzed on preadipocyte differentiation,lipid content,lipid droplet size and number,the expression of adipogenic-specific transcriptional factors,as well as cell survival.From our examinations,we found the Annona montana ethyl acetate extract to exhibit a potent inhibitory effect on adipogenesis,without affecting cell survival,in a dose-dependent manner.Such inhibitory effects included a significant decrease in the accumulation of lipid content by both a dramatic reduction of size and number of lipid droplets.This extract strongly attenuated the expression of PPARγand HMGB2.It also inhibited the expression of CEBPα,FAS,and Akt without influencing Erk1/2 activities.Our findings suggest that specifically,the Annona montana ethyl acetate extract has a prominent inhibitory effect in cellular pathways of adipocyte differentiation by modulating specific gene expression,which is known to perform a pivotal role during adipogenesis.
基金Supported by the National Natural Science Foundation of China(21476121,21322604)Beijing Natural Science Foundation(2162020)a Foundation for Tsinghua Independent Research Projects(2014z21026)
文摘In this article, a theoretical model for predicting the equilibrium morphology of gas–liquid Janus droplets was built. Based on this model, the effects of bubble radius and volume ratio on morphology change was systematically studied. The increase of bubble radius causes the two parts(bubble and oil drop) in Janus droplets tend to merge while the impact of volume ratio is complicated. When volume ratio increases, these two parts firstly tend to merge, then gradually separate. The accuracy of this model was verified by experimental results.
文摘Vortexing limestone injection into furnace combined with calcium lime hydration in the downstream is the most promising technology for controlling SO 2 emission. Particle imaging velocimetry (PIV) is used to measure the gas liquid solid three phase flow field in a reactor. By image processing based on newly developed software, the number concentrations of sorbent particles and water droplets are presented. The measuring results are very helpful for better understanding the desulfurization mechanism and optimizing configurational and operational parameters in the hydration reactor.
文摘The maximum entropy principle(MEP) is one of the first methods which have been used to predict droplet size and velocity distributions of liquid sprays. This method needs a mean droplets diameter as an input to predict the droplet size distribution. This paper presents a new sub-model based on the deterministic aspects of liquid atomization process independent of the experimental data to provide the mean droplets diameter for using in the maximum entropy formulation(MEF). For this purpose, a theoretical model based on the approach of energy conservation law entitled energy-based model(EBM) is presented. Based on this approach, atomization occurs due to the kinetic energy loss. Prediction of the combined model(MEF/EBM) is in good agreement with the available experimental data. The energy-based model can be used as a fast and reliable enough model to obtain a good estimation of the mean droplets diameter of a spray and the combined model(MEF/EBM) can be used to well predict the droplet size distribution at the primary breakup.
基金supported by the UK EPSRC under grant EP/D500125/01.
文摘This paper presents a molecular dynamics simulation of the behaviours of non-polar droplets merging and also the fluid molecules interacting with a hydrophobic surface. Such behaviours and transport phenomena are popular in general microchannel flow boiling and two-phase flow. The droplets are assumed to be composed of Lennards-Jones type molecules. Periodic boundary conditions are applied in three coordinate directions of a 3-D system, where there exist two liquid droplets and their vapour. The two droplets merge when they come within the prescribed small distance. The merging of two droplets apart from each other at different initial distances is tested and the possible larger (or critical) non-dimensional distance, in which droplets merging can occur, is discussed. The evolution of the merging process is simulated numerically by employing the Molecular Dynamics (MD) method. For interactions with hydrophobic solid wall, a system with fluid confined between two walls is used to study the wetting phenomena of fluid and solid wall. The results are compared with those of hydrophilic wall to show the unique characteristics of hydrophobic interactions by microscopic methods.
基金the National Natural Science Foundation of China(Nos.10572076,10672089)
文摘Three-phase line tensions may become crucial in the adhesion of miero-nano or small droplets on solid planes. In this paper we study for the first time the nonlinear effects in adhesion spanning the full range of physically possible parameters of surface tension, line tension, and droplet size. It is shown that the nonlinear adhesion solution spaces can be characterized into four regions. Within each region the adhesion behaves essentially the same. Especially, inside the characteristic regions with violent nonlinearities, the co-existence of multiple adhesion states for given materials is disclosed. Besides, two common fixed points in the solution space are revealed. These new results are consistent with numerical analysis and experimental observations reported in the literatures.
基金Project supported by the Engineering Research Center of Eco-environment in the Three Gorges Reservoir Region(Grant No.KF2019-10)。
文摘The impact of droplets on the liquid film is widely involved in industrial and agricultural fields.In recent years,plenty of works are limited to dry walls or stationary liquid films,and the research of multi-droplet impact dynamic films is not sufficient.Based on this,this paper employs a coupled level set and volume of fluid(CLSVOF) method to numerically simulate two-droplet impingement on a dynamic liquid film.In our work,the dynamic film thickness,horizontal central distance between the droplets,droplets’ initial impact speed,and simultaneously the flow velocity of the moving film are analyzed.The evolution phenomenon and mechanism caused by the collision are analyzed in detail.We find that within a certain period of time,the droplet spacing does not affect the peripheral crown height;when the droplet spacing decreases or the initial impact velocity increases,the height of the peripheral crown increases at the beginning,and then,because the crown splashed under Rayleigh-Plateau instability,this results in the reduction of the crown height.At the same time,it is found that when the initial impact velocity increases,the angle between the upstream peripheral jet and the dynamic film becomes larger.The more obvious the horizontal movement characteristics,the more restrained the crown height;the spread length increases with the increase of the dynamic film speed,droplet spacing and the initial impact velocity.When the liquid film is thicker,more fluid enters the crown,due to the crown being unstable,the surface tension is not enough to overcome the weight of the rim at the end of the crown,resulting in droplets falling off.