Insulin is an essential and versatile protein taking part in the control of blood glucose levels and protein anabolism.However,under prolonged storage or high temperature stress,insulin tends to unfold and aggregate i...Insulin is an essential and versatile protein taking part in the control of blood glucose levels and protein anabolism.However,under prolonged storage or high temperature stress,insulin tends to unfold and aggregate into toxic amyloid fibrils,leading to loss of physiological function.Inspired by natural chaperones,a series of temperature-sensitive polycaprolactone-based micelles were designed to prevent insulin from deactivation.The micelles were fabricated through the self-assembly of amphiphilic copolymers of methoxy poly(ethylene glycol)-poly(4-diethylformamide caprolactone-co-caprolactone)(mPEG_(17)-P(DECL-co-CL)),which had a regular spherical morphology with particle sizes of about 100 nm.In addition,the lower critical solution temperature(LCST)of the micelles could be tuned to 9 and 29℃by changing the ratio of DECL to CL.Benefiting from the temperature-sensitivity of DECL segment,the binding ability of micelles to insulin could be modulated by changing the temperature.Above LCST,micelles effectively inhibited insulin aggregation and protected it from thermal inactivation due to the strong binding ability between the hydrophobic segment DECL and insulin.Below LCST,DECL segment returned to hydrophilic and bound weakly with insulin,leading to the release of insulin and assisting in its recovery of secondary structure.Thus,these temperature-sensitive micelles provided an effective strategy for insulin protection.展开更多
A new series of cellulose-graft-poly（N-isopropylacrylamide） （cellulose-g-PNIPAM） copolymers were prepared by atom transfer radical polymerization （ATRP） of N-isopropylacrylamide monomers from a cellulose-based m...A new series of cellulose-graft-poly（N-isopropylacrylamide） （cellulose-g-PNIPAM） copolymers were prepared by atom transfer radical polymerization （ATRP） of N-isopropylacrylamide monomers from a cellulose-based macro-initiator, which was homogeneously synthesized in an ionic liquid 1-allyl-3-methylimidazolium chloride （AmimC1）. The composition of cellulose-g-PNIPAM copolymers could be adjusted by altering the feeding ratio and reaction time. The resultant copolymers with relatively high content of PNIPAM segments （molar substitution of PNIPAM ≥ 18.3） were soluble in water at room temperature. Aqueous solutions of cellulose-g-PNIPAM copolymers exhibited clear temperature-sensitive behavior, and their sol-to-gel phase transition properties were investigated by dynamic light scattering （DLS） and UV measurements. Compared with pure PNIPAM, the cellulose-g-PNIPAM copolymers possessed higher lower critical solution temperatures （LCST） in a range from 36.9 ℃ to 40.8 ℃, which are close to normal human body temperature, and could be tuned by adjusting the content of PNIPAM segments in copolymers. Spherical structure of cellulose-g-PNIPAM copolymers formed at temperatures above LCST and its morphology was observed by TEM and SEM. These novel cellulose-g-PNIPAM copolymers may be attractive substrates for some biomedical applications, such as drug release and tissue engineering.展开更多
The strong background radiation in high enthalpy hypersonic shock tunnels has posed severe challenges for measurement using luminescent coatings.We proposed a solution for reducing background radiation from time-resol...The strong background radiation in high enthalpy hypersonic shock tunnels has posed severe challenges for measurement using luminescent coatings.We proposed a solution for reducing background radiation from time-resolved temperature-sensitive paint(TSP)measurement in a hypersonic flow with Ma=6.5 and T_(0)=3525 K.The TSP was applied on an inlet ramp model,and the images were taken by a high-speed camera at 2 kHz under a modulated excitation.The strong background radiation led to a low signal-to-noise ratio and significant errors for the first half of the 130-ms test duration.Accordingly,three noise reduction methods were developed and evaluated based on temporal reconstruction,spatial reconstruction and robust principal component analysis(RPCA),respectively.The RPCA method showed the best performance that successfully recovered high-quality TSP data for a majority of test duration(t≥40 ms).展开更多
Aiming at the deficiency of the robustness of thermal error compensation models of CNC machine tools, the mechanism of improving the models＇ robustness is studied by regarding the Leaderway-V450 machining center as t...Aiming at the deficiency of the robustness of thermal error compensation models of CNC machine tools, the mechanism of improving the models＇ robustness is studied by regarding the Leaderway-V450 machining center as the object. Through the analysis of actual spindle air cutting experimental data on Leaderway-V450 machine, it is found that the temperature-sensitive points used for modeling is volatility, and this volatility directly leads to large changes on the collinear degree among modeling independent variables. Thus, the forecasting accuracy of multivariate regression model is severely affected, and the forecasting robustness becomes poor too. To overcome this effect, a modeling method of establishing thermal error models by using single temperature variable under the jamming of temperature-sensitive points＇ volatility is put forward. According to the actual data of thermal error measured in different seasons, it is proved that the single temperature variable model can reduce the loss of fore- casting accuracy resulted from the volatility of tempera- ture-sensitive points, especially for the prediction of cross quarter data, the improvement of forecasting accuracy is about 5 μm or more. The purpose that improving the robustness of the thermal error models is realized, which can provide a reference for selecting the modelingindependent variable in the application of thermal error compensation of CNC machine tools.展开更多
Groundwater lowering is one of the most important countermeasures to avoid the risk of rainfall-triggered landslides.However,the long-term reliability of many drainage methods is often a matter of concern since the dr...Groundwater lowering is one of the most important countermeasures to avoid the risk of rainfall-triggered landslides.However,the long-term reliability of many drainage methods is often a matter of concern since the drains may easily get clogged.A new hydraulic-driven self-starting drainage method is presented in this paper.In the proposed Random Forest(RF)based robust design approach for the selfstarting drains,the datasets are generated using an automatically controlled numerical modeling technology.The deterministic analysis is carried out based on uncertain soil parameters and the specific designs selected using Uniform Design(UD).The ensemble of RF models is applied in the design process to improve computing efficiency.Safety requirements,design robustness,and cost efficiency are simultaneously considered utilizing multiobjective optimization.A straightforward and efficient framework that focuses on difficulties caused by an enormous design space is established for the robust design of the self-starting drains,and improved computation efficiency is achieved.The effectiveness of the proposed approach is illustrated with a case study,the Qili landslide in Zhejiang Province,China.展开更多
To develop a smart free-standing surface enhanced Raman scattering(SERS) substrate,silver nanoparticles(AgNPs) embedded temperature-sensitive nanofibrous membrane was fabricated by electrospinning their aqueous soluti...To develop a smart free-standing surface enhanced Raman scattering(SERS) substrate,silver nanoparticles(AgNPs) embedded temperature-sensitive nanofibrous membrane was fabricated by electrospinning their aqueous solution containing the copolymer poly(N-isopropylacrylamide-co-Nhydroxymethylacrylamide),followed by heat treatment to form crosslinking structure within its constituent nanofibers.To avoid negative effect of the additive like stabilizer and the reactant like reductant on their SERS efficiency,the AgNPs were in-situ synthesized through reducing Ag^+ions dissolved in the polymer solution by ultraviolet irradiation.The prepared hybrid nanofibrous membrane with high stability in aqueous medium can reach its swelling or deswelling equilibrium state within 15 seconds with the medium temperature changing between 25℃and 50℃alternately.When it was used as a free-standing SERS substrate,10^-12 mol/L of 4-nitrothiophenol in aqueous solution can be detected at room temperature,and elevating detection temperature can further lower its low detection limit.Since its generated SERS signal has desirable reproducibility,it can be used as SERS substrate for quantitative analysis.Moreover,the hybrid membrane as SERS substrate is capable of real-time monitoring the reduction of 4-nitrothiophenol into 4-aminothiophenol catalyzed by its embedded AgNPs,and the detected intermediate indicates that the reaction proceeds via a condensation route.展开更多
The forecast of sterile alteration for the temperature-sensitive genic male sterile （TGMS） line in two-line hybrid rice seed production was traditionally based on screen temperature determined by weather station. Th...The forecast of sterile alteration for the temperature-sensitive genic male sterile （TGMS） line in two-line hybrid rice seed production was traditionally based on screen temperature determined by weather station. The article put forward a new approach based on plant temperature, which was more exact and direct than the traditional method. The result of the simulation of the self-seeded setting rate of a widely used TGMS line, Peiai64S, by several temperature parameters and durations, showed that the fertility was directly affected by the plant temperature at a height of 20 cm or the air temperature around it in three days duration. Using the stem temperature of three days at a height of 20 cm as the simulation parameter, the fertility of Peiai64S had the maximum, minimum and optimum temperatures as 22.8, 21.7 and 22.5℃, respectively, whereas 23.2, 21.5 and 21.8℃ when using the air temperature of three days around the height of 20 cm as the parameter. Such temperature indices can be used to conclude the sterile alteration of TGMS for safeguarding seed production of twoline hybrid rice. The article also established a statistic model to conclude plant temperature by water temperatures at inflow and outflow, and air temperature and cloudage from weather station.展开更多
The present work deals with an investigation of the self-starting aerodynamic characteristics of VAWT under fluctuating wind. In contrast to the previous studies, the rotational speed of the turbine is not fixed, the ...The present work deals with an investigation of the self-starting aerodynamic characteristics of VAWT under fluctuating wind. In contrast to the previous studies, the rotational speed of the turbine is not fixed, the rotation of the turbine is determined by the dynamic interaction between the fluctuating wind and turbine. A weak coupling method is developed to simulate the dynamic interaction between the fluctuating wind and passive rotation turbine, and the results show that if the fluctuating wind with appropriate fluctuation amplitude and frequency, the self-starting aerodynamic characteristics of VAWT will be enhanced. It is also found that compared with the fluctuation amplitude, the fluctuation frequency of the variation in wind velocity is shown to have a minor effect on the performance of the turbine. The analysis will provide straightforward physical insight into the self-starting aerodynamic characteristics of VAWT under fluctuating wind.展开更多
A stable continuous wave mode-locked picosecond Ti：sapphire laser by using a fast semiconductor saturable absorber mirror （SESAM） is demonstrated. The laser delivers pulse width of 20 ps at a central wavelength of ...A stable continuous wave mode-locked picosecond Ti：sapphire laser by using a fast semiconductor saturable absorber mirror （SESAM） is demonstrated. The laser delivers pulse width of 20 ps at a central wavelength of 813 nm and a repetition rate of 100 MHz. The maximum output power is 1.34 W with pump power of 7 W which corresponds to an optical^optical conversion efficiency of 19.1%.展开更多
A novel series of poly(N-isopropylacrylamide-co-hydroxyethyl methacrylate) (p(NIPAM-co-HEMA)) microgels were prepared through precipitation polymerization. Nuclear magnetic resonance (NMR), transmission electron micro...A novel series of poly(N-isopropylacrylamide-co-hydroxyethyl methacrylate) (p(NIPAM-co-HEMA)) microgels were prepared through precipitation polymerization. Nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV) and dynamic light scattering (DLS) were employed to characterize the microgels. The experimental results indicate that the prepared microgels with narrow distribution remain good temperature sensitivity after incorporation of functional-OH groups. In marked contrast to the general rule, incorporation of hydrophilic HEMA makes the volume-phase-transition temperature shift to the lower temperature due to the strong intermolecular H-bonding between amide and -OH groups, -OH and -OH groups.展开更多
In this study,wind tunnel experiment was carried out to investigate the self-staring capability for straight-bladed vertical axis wind turbine.The flow visualization also was been performed at the rest of the rotor.Th...In this study,wind tunnel experiment was carried out to investigate the self-staring capability for straight-bladed vertical axis wind turbine.The flow visualization also was been performed at the rest of the rotor.The effect of the azimuthal angle of blade position relative to wind direction on the self-starting capability was discussed based on the results of flow visualization.The torque and centripetal force of the rotor when the self-starting behavior starts were roughly calculated with the flow visualization results of the rotor.It is suggested that there exists the condition of wind speed and configuration of the blade position of the rotor at the rest of rotor to the reach to situational rotation number.展开更多
A temperature-sensitive (ts) mutant of the CHO-K1 cell line, tsTM18, grows at 340C but not at 390C. Smu1 is the gene responsible for ts defects of tsTM18 cells. Previously, we found that the Smu1 ts defect altered the...A temperature-sensitive (ts) mutant of the CHO-K1 cell line, tsTM18, grows at 340C but not at 390C. Smu1 is the gene responsible for ts defects of tsTM18 cells. Previously, we found that the Smu1 ts defect altered the localization (as indicated by enlargement of speckles) of SRSF1 (SF2/ASF) in tsTM18 cells cultured at 390C, suggesting a functional association between Smu1 and SRSF1. Speckles are subnuclear structures that may function as storage/assembly/ modification compartments to supply splicing factors to active transcription sites. The effect of the ts defect of Smu1 on the localization of other factors related to splicing has not been characterized yet. The mechanisms underlying the enlargement of speckles of SRSF1 remain unclear. In the present study, we found that the ts defect of Smu1 affected the nuclear localization of a splicing factor, SRSF2 (SC35), and factors involved in the exon-exon junction complex, Y14 and ALY. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that the ts defect of Smu1 affected alternative splicing of endogenous Clk1/ Sty and SRSF2 genes. Mammalian Clk family kinases are shown to phosphorylate serine/arginine (SR) proteins in vitro and SRSF1 in vivo. RT-PCR analysis of Clk1/Sty showed an accumulation of the truncated form lacking kinase activity in tsTM18 cells incubated at 39?C. These data indicate that an accumulation of kinase-negative Clk1/Sty may lead to alteration of the localization of factors related to splicing resulting in the enlargement of speckles.展开更多
Silk has been widely used in the clothing industry due to their soft and smooth features,good biocompatibility,good heat dissipation,warmth and ultraviolet resistance.The application of fragrance to silk can significa...Silk has been widely used in the clothing industry due to their soft and smooth features,good biocompatibility,good heat dissipation,warmth and ultraviolet resistance.The application of fragrance to silk can significantly improve the performance of silk.However,there are two key scientific problems that need to be solved:slowing down the release rate of fragrances and increasing the scent lasting time of silk.In this study,cationic and temperature-sensitive liposomes were designed and prepared to encapsulate eugenol.These fragrance-loaded liposomes significantly slowed down the release rate of the fragrance and controlled the release rate of the fragrance in a thermo-sensitive manner.The liposomes adhered to the silk through electrostatic adsorption interaction.The positive charge on the fragranceloaded liposomes neutralized much negative charge on silk and thereby increasing the adhesion efficiency.展开更多
A kind of novel copolymer hydrogel of poly（N, N-dimethylaminoethyl methacrylate-co-N-isopropylacrylamide） （poly[DMAEMA/NIPAAm]） was synthesized by the initiation of K2S2O8, N, N＇-methylene-bis（acrylamide） （Bis...A kind of novel copolymer hydrogel of poly（N, N-dimethylaminoethyl methacrylate-co-N-isopropylacrylamide） （poly[DMAEMA/NIPAAm]） was synthesized by the initiation of K2S2O8, N, N＇-methylene-bis（acrylamide） （Bis） was used as the crosslinker. The effects of monomer content, pH and temperature on swelling ratio of the hydrogel were investigated; the thermo-sensitivity in deionized water and in physiological saline was determined. It showed that the swelling ratio of the hydrogel could be changed by changing the temperature or pH alternately. Both swelling ratio and LCST （Lower Critical Solution Temperature） of the hydrogel decreased with the increase of NIPAAm in the co-polymer content.展开更多
The swelling behavior of a temperature-sensitive poly-N-isopropylacrylamide(PNIPAM) hydrogel circular cylinder is studied subjected to combined extension-torsion and varied temperature. In this regard, a semi-analytic...The swelling behavior of a temperature-sensitive poly-N-isopropylacrylamide(PNIPAM) hydrogel circular cylinder is studied subjected to combined extension-torsion and varied temperature. In this regard, a semi-analytical solution is proposed for general combined loading. A finite element(FE) analysis is conducted, subjecting a hydrogel cylinder to the combined extension-torsion and the varied temperature to evaluate the validity and accuracy of the solution. A user-defined UHYPER subroutine is developed and verified under free and constrained swelling conditions. The FE results illustrate excellent agreement with the semi-analytical solution. Due to the complexity of the problem, some compositions and applied loading factors are analyzed. It is revealed that for larger cross-linked density and larger ending temperature, the cylinder yields higher stresses and smaller radial swelling deformation. Besides, the radial and hoop stresses increase by applying larger twist and axial stretch. The hoop stresses intersect at approximately R/Rout = 0.58, where the hoop stress vanishes. Besides, the axial force has direct and inverse relationships with the axial stretch and the twist, respectively. However, the resultant torsional moment behavior is complex, and the position of the maximum point varies significantly by altering the axial stretch and the twist.展开更多
Rapidly-advancing microneedle-based bioelectronics integrated with electrical stimulation(ES)therapy exhibit significant potential for improving chronic wound management.Herein,bio-inspired by the serrated structure o...Rapidly-advancing microneedle-based bioelectronics integrated with electrical stimulation(ES)therapy exhibit significant potential for improving chronic wound management.Herein,bio-inspired by the serrated structure of bee-stingers,we developed a temperature-sensitive,two-stage microneedle-based electro active platform(GP-PPy/PLA-MN)featuring rivet-like micros tructures that integrates intelligent,precise drug-releasing,ES-transmission,and real-time wound-assessment monitoring for comprehensive chronic wound-management and diagnostic therapy.The bionic-design mechanically anchors the microneedle beneath the skin's dermis,while GP-PPy/PLA-MN demonstrates versatile therapeutic characteristics,including outstanding biocompatibility,antimicrobial properties,and antimigratory origins.The GP-PPy/PLA-MN enables the sustained release of insulin at body temperature for up to24 hours through the poly-N-isopropyl acrylamide grafted amidated-gelatin-based thermo-sensitive hydrogel at the needle-tip,thereby providing long-term stable blood glucose control.GP-PPy/PLA-MN indicates its potential as a novel bioelectronics-based patch to record the temperature and humidity during the wound-healing process,realizing significant wound diagnosis and real-time wound assessment,and fundamentally facilitating the therapeutic efficacy by supplying solid data to protect the clinical practice.Extensive in vitro and in vivo studies have demonstrated that GP-PPy/PLA-MN can provide effective ES and sustained drug release,thereby promoting chronic wound healing and increasing the wound healing rate by 20%compared to the control group after 14 days of treatment.This innovative approach combines bioelectronics with intelligent drug delivery and microneedling technology to effectively address the critical challenges of chronic wound management,offering promising prospects for precision diagnostics and therapeutic interventions.展开更多
An experimental study on the boundary layer transition over a delta wing was carried out at Mach number 6 in a quiet wind tunnel.The Nano-tracer-based Planar Laser Scattering(NPLS)and Temperature-Sensitive Paints(TSP)...An experimental study on the boundary layer transition over a delta wing was carried out at Mach number 6 in a quiet wind tunnel.The Nano-tracer-based Planar Laser Scattering(NPLS)and Temperature-Sensitive Paints(TSP)techniques were used to measure the fine flow field structure and the wall Stanton number of the delta wing.The influence of factors such as the angle of attack and the Reynolds number was studied.The following results were obtained.The boundary layer transition between the leading edge and the centerline was dominated by the crossflow instability.At the location of the initial appearance of the traveling crossflow waves,the Stanton number began to rise.The Stanton number reached a maximum when the crossflow waves were broken up to turbulence.Increasing the angle of attack increased the spanwise pressure gradient at the windward side of the delta wing,thereby increasing the crossflow instability and advancing the boundary layer transition front.However,increasing the angle of attack caused the transition front to move backward at the leeward side.In addition,the sensitivity of the boundary layer transition to the Reynolds number varied with the angle of attack and the region.展开更多
Smart materials with a combination of tough solid-like properties,fast self-healing and optical responsiveness are of interests for the development of new soft machines and wearable electronics.In this work,tough phys...Smart materials with a combination of tough solid-like properties,fast self-healing and optical responsiveness are of interests for the development of new soft machines and wearable electronics.In this work,tough physically cross-linked elastomers that show high mechanical strength,intriguing temperature-adaptable self-healing and fluorochromic response properties are designed using aluminum(Al)and fluorescent europium(Eu)ions as cross-linkers.The ionic Al-COOH binding is incorporated to construct the strong polymer network which mainly contributes to the mechanical robustness of the elastomer consisting of two interpenetrated networks.The Eu-iminodiacetate(IDA)coordination is mainly used to build the weaker but more dynamic network which dominate the elasticity,self-healing and luminescence of the elastomer.Moderate Eu^(3+) and Al^(3+) contents give these supramolecular elastomers high toughness.The temperature-sensitive Eu-IDA coordination enables tunable self-healing rate and efficiency along with fast Eu-centered"ON/OFF"switchable red emission.The mechanical,self-healing and luminescence properties of these elastomers can be adjusted by tuning the ratio of the two types of metal ions.This elastomer is potentially applicable for biosensors,wearable optoelectronics and anticounterfeiting materials.展开更多
A novel method for the synthesis of macrocyclic graft copolymers was developed through combination of anionic ring-opening polymerization (AROP) and atom transfer radical polymerization (ATRP).A linear α,ω-dihydroxy...A novel method for the synthesis of macrocyclic graft copolymers was developed through combination of anionic ring-opening polymerization (AROP) and atom transfer radical polymerization (ATRP).A linear α,ω-dihydroxyl poly(ethylene oxide) with pendant acetal protected hydroxyl groups (l-poly(EO-co-EEGE)) was prepared first by the anionic copolymerization of ethylene oxide (EO) and ethoxyethyl glycidyl ether (EEGE).Then l-poly(EO-co-EEGE) was cyclized.The crude cyclized product containing the linear byproduct was hydrolyzed and purified by being treated with α-CD.The pure cyclic copolymer [c-poly(EO-co-Gly)] was esterified by reaction with 2-bromoisobutyryl bromide,and then used as ATRP macroinitiators to initiate polymerization of 2-(dimethylamino) ethyl methacrylate (DMAEMA),and a series of pH-and temperature-sensitive macrocyclic graft copolymers composed of a hydrophilic PEO as the ring and PDMAEMA as side chains (c-PEO-g-PDMAEMA) were obtained.The behavior of pH-and temperature-sensitive macrocyclic copolymers was studied in aqueous solution by fluorescence and dynamic light scattering (DLS).The critical micellization pH values of macrocyclic graft copolymers and their corresponding linear graft copolymers (l-PEO-g-PDMAEMA) were measured.Under the same conditions,the cyclic graft copolymer with the shorter side chains gave the higher critical micellization pH value.The c-PEO-g-PDMAEMA showed the lower critical micellization pH value than the corresponding l-PEO-g-PDMAEMA.The average hydrodynamic diameters (Dh) of the micelles were measured by DLS with the variation of the aqueous solution pH value and temperature.展开更多
For the first time, we are reporting a novel type of dual fluorescence temperaturesensitive DNA-templated silver nanocluster （AgNC） pair, which contains two pieces of single-stranded AgNC in proximity through hybrid...For the first time, we are reporting a novel type of dual fluorescence temperaturesensitive DNA-templated silver nanocluster （AgNC） pair, which contains two pieces of single-stranded AgNC in proximity through hybridization. Both the chameleon AgNC pairs, A-NCP and B-NCP, possess two bright fluorescence peaks that achieve sensitive variations corresponding to temperature change from 15 to 45 ℃. With the increase in temperature, one of the fluorescence emissions of A-NCP （A-FL570） increases, while the other （A-FL640） decreases. However, both the emissions of B-NCP （B-FL685 and B-FL620） decrease simultaneously. Therefore, A-NCP shows a remarkable fluorescence color variation from orange to yellow, while the fluorescence color of B-NCP changes from orange to colorless, with increase in temperature. Moreover, the temperature responding linear range of A-NCP can be regulated by adjusting the structures and sequences of assistant DNA templates. It is assumed that the two single-stranded segmental AgNCs are integrated together as they are assembled into AgNC pairs, leading to a dramatic variation in fluorescence properties. The temperature-sensitive phenomenon is due to the dehybridization-induced separation of two pieces of segmental AgNC, caused by temperature increase. The temperature-sensitive AgNC pairs have been successful in indicating the temperature of living cells, showing the potential for a new application of silver nanocluster as a nanothermometer with adjustable response range, bringing novel insight into the regulatory mechanism of AgNC fluorescence variation.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52273009 and 21674037).
文摘Insulin is an essential and versatile protein taking part in the control of blood glucose levels and protein anabolism.However,under prolonged storage or high temperature stress,insulin tends to unfold and aggregate into toxic amyloid fibrils,leading to loss of physiological function.Inspired by natural chaperones,a series of temperature-sensitive polycaprolactone-based micelles were designed to prevent insulin from deactivation.The micelles were fabricated through the self-assembly of amphiphilic copolymers of methoxy poly(ethylene glycol)-poly(4-diethylformamide caprolactone-co-caprolactone)(mPEG_(17)-P(DECL-co-CL)),which had a regular spherical morphology with particle sizes of about 100 nm.In addition,the lower critical solution temperature(LCST)of the micelles could be tuned to 9 and 29℃by changing the ratio of DECL to CL.Benefiting from the temperature-sensitivity of DECL segment,the binding ability of micelles to insulin could be modulated by changing the temperature.Above LCST,micelles effectively inhibited insulin aggregation and protected it from thermal inactivation due to the strong binding ability between the hydrophobic segment DECL and insulin.Below LCST,DECL segment returned to hydrophilic and bound weakly with insulin,leading to the release of insulin and assisting in its recovery of secondary structure.Thus,these temperature-sensitive micelles provided an effective strategy for insulin protection.
基金financially supported by the National Natural Science Foundation of China(No.51425307)
文摘A new series of cellulose-graft-poly（N-isopropylacrylamide） （cellulose-g-PNIPAM） copolymers were prepared by atom transfer radical polymerization （ATRP） of N-isopropylacrylamide monomers from a cellulose-based macro-initiator, which was homogeneously synthesized in an ionic liquid 1-allyl-3-methylimidazolium chloride （AmimC1）. The composition of cellulose-g-PNIPAM copolymers could be adjusted by altering the feeding ratio and reaction time. The resultant copolymers with relatively high content of PNIPAM segments （molar substitution of PNIPAM ≥ 18.3） were soluble in water at room temperature. Aqueous solutions of cellulose-g-PNIPAM copolymers exhibited clear temperature-sensitive behavior, and their sol-to-gel phase transition properties were investigated by dynamic light scattering （DLS） and UV measurements. Compared with pure PNIPAM, the cellulose-g-PNIPAM copolymers possessed higher lower critical solution temperatures （LCST） in a range from 36.9 ℃ to 40.8 ℃, which are close to normal human body temperature, and could be tuned by adjusting the content of PNIPAM segments in copolymers. Spherical structure of cellulose-g-PNIPAM copolymers formed at temperatures above LCST and its morphology was observed by TEM and SEM. These novel cellulose-g-PNIPAM copolymers may be attractive substrates for some biomedical applications, such as drug release and tissue engineering.
基金supported by the National Natural Science Foundation of China(Grants 11725209 and 11872038)and funding from Gas Turbine Research Institute of Shanghai Jiao Tong University.
文摘The strong background radiation in high enthalpy hypersonic shock tunnels has posed severe challenges for measurement using luminescent coatings.We proposed a solution for reducing background radiation from time-resolved temperature-sensitive paint(TSP)measurement in a hypersonic flow with Ma=6.5 and T_(0)=3525 K.The TSP was applied on an inlet ramp model,and the images were taken by a high-speed camera at 2 kHz under a modulated excitation.The strong background radiation led to a low signal-to-noise ratio and significant errors for the first half of the 130-ms test duration.Accordingly,three noise reduction methods were developed and evaluated based on temporal reconstruction,spatial reconstruction and robust principal component analysis(RPCA),respectively.The RPCA method showed the best performance that successfully recovered high-quality TSP data for a majority of test duration(t≥40 ms).
基金Supported by Key Project of National Natural Science Fund of China(Grant No.51490660/51490661)National Natural Science Foundation of China(Grant No.51175142)
文摘Aiming at the deficiency of the robustness of thermal error compensation models of CNC machine tools, the mechanism of improving the models＇ robustness is studied by regarding the Leaderway-V450 machining center as the object. Through the analysis of actual spindle air cutting experimental data on Leaderway-V450 machine, it is found that the temperature-sensitive points used for modeling is volatility, and this volatility directly leads to large changes on the collinear degree among modeling independent variables. Thus, the forecasting accuracy of multivariate regression model is severely affected, and the forecasting robustness becomes poor too. To overcome this effect, a modeling method of establishing thermal error models by using single temperature variable under the jamming of temperature-sensitive points＇ volatility is put forward. According to the actual data of thermal error measured in different seasons, it is proved that the single temperature variable model can reduce the loss of fore- casting accuracy resulted from the volatility of tempera- ture-sensitive points, especially for the prediction of cross quarter data, the improvement of forecasting accuracy is about 5 μm or more. The purpose that improving the robustness of the thermal error models is realized, which can provide a reference for selecting the modelingindependent variable in the application of thermal error compensation of CNC machine tools.
基金supported by the National Natural Science Foundation of China(Grant No.41772276)the Key R&D project of Zhejiang Province(Grant No.2017C03006)the Zhejiang University and the Norwegian Geotechnical Institute for funding his research stay at NGI。
文摘Groundwater lowering is one of the most important countermeasures to avoid the risk of rainfall-triggered landslides.However,the long-term reliability of many drainage methods is often a matter of concern since the drains may easily get clogged.A new hydraulic-driven self-starting drainage method is presented in this paper.In the proposed Random Forest(RF)based robust design approach for the selfstarting drains,the datasets are generated using an automatically controlled numerical modeling technology.The deterministic analysis is carried out based on uncertain soil parameters and the specific designs selected using Uniform Design(UD).The ensemble of RF models is applied in the design process to improve computing efficiency.Safety requirements,design robustness,and cost efficiency are simultaneously considered utilizing multiobjective optimization.A straightforward and efficient framework that focuses on difficulties caused by an enormous design space is established for the robust design of the self-starting drains,and improved computation efficiency is achieved.The effectiveness of the proposed approach is illustrated with a case study,the Qili landslide in Zhejiang Province,China.
基金the National Natural Science Foundation of China(Nos.51503033,51373030)
文摘To develop a smart free-standing surface enhanced Raman scattering(SERS) substrate,silver nanoparticles(AgNPs) embedded temperature-sensitive nanofibrous membrane was fabricated by electrospinning their aqueous solution containing the copolymer poly(N-isopropylacrylamide-co-Nhydroxymethylacrylamide),followed by heat treatment to form crosslinking structure within its constituent nanofibers.To avoid negative effect of the additive like stabilizer and the reactant like reductant on their SERS efficiency,the AgNPs were in-situ synthesized through reducing Ag^+ions dissolved in the polymer solution by ultraviolet irradiation.The prepared hybrid nanofibrous membrane with high stability in aqueous medium can reach its swelling or deswelling equilibrium state within 15 seconds with the medium temperature changing between 25℃and 50℃alternately.When it was used as a free-standing SERS substrate,10^-12 mol/L of 4-nitrothiophenol in aqueous solution can be detected at room temperature,and elevating detection temperature can further lower its low detection limit.Since its generated SERS signal has desirable reproducibility,it can be used as SERS substrate for quantitative analysis.Moreover,the hybrid membrane as SERS substrate is capable of real-time monitoring the reduction of 4-nitrothiophenol into 4-aminothiophenol catalyzed by its embedded AgNPs,and the detected intermediate indicates that the reaction proceeds via a condensation route.
文摘The forecast of sterile alteration for the temperature-sensitive genic male sterile （TGMS） line in two-line hybrid rice seed production was traditionally based on screen temperature determined by weather station. The article put forward a new approach based on plant temperature, which was more exact and direct than the traditional method. The result of the simulation of the self-seeded setting rate of a widely used TGMS line, Peiai64S, by several temperature parameters and durations, showed that the fertility was directly affected by the plant temperature at a height of 20 cm or the air temperature around it in three days duration. Using the stem temperature of three days at a height of 20 cm as the simulation parameter, the fertility of Peiai64S had the maximum, minimum and optimum temperatures as 22.8, 21.7 and 22.5℃, respectively, whereas 23.2, 21.5 and 21.8℃ when using the air temperature of three days around the height of 20 cm as the parameter. Such temperature indices can be used to conclude the sterile alteration of TGMS for safeguarding seed production of twoline hybrid rice. The article also established a statistic model to conclude plant temperature by water temperatures at inflow and outflow, and air temperature and cloudage from weather station.
基金Projects(61105086,51505347)supported by the National Natural Science Foundation of China
文摘The present work deals with an investigation of the self-starting aerodynamic characteristics of VAWT under fluctuating wind. In contrast to the previous studies, the rotational speed of the turbine is not fixed, the rotation of the turbine is determined by the dynamic interaction between the fluctuating wind and turbine. A weak coupling method is developed to simulate the dynamic interaction between the fluctuating wind and passive rotation turbine, and the results show that if the fluctuating wind with appropriate fluctuation amplitude and frequency, the self-starting aerodynamic characteristics of VAWT will be enhanced. It is also found that compared with the fluctuation amplitude, the fluctuation frequency of the variation in wind velocity is shown to have a minor effect on the performance of the turbine. The analysis will provide straightforward physical insight into the self-starting aerodynamic characteristics of VAWT under fluctuating wind.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 60225005 and 60308001）.
文摘A stable continuous wave mode-locked picosecond Ti：sapphire laser by using a fast semiconductor saturable absorber mirror （SESAM） is demonstrated. The laser delivers pulse width of 20 ps at a central wavelength of 813 nm and a repetition rate of 100 MHz. The maximum output power is 1.34 W with pump power of 7 W which corresponds to an optical^optical conversion efficiency of 19.1%.
文摘A novel series of poly(N-isopropylacrylamide-co-hydroxyethyl methacrylate) (p(NIPAM-co-HEMA)) microgels were prepared through precipitation polymerization. Nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV) and dynamic light scattering (DLS) were employed to characterize the microgels. The experimental results indicate that the prepared microgels with narrow distribution remain good temperature sensitivity after incorporation of functional-OH groups. In marked contrast to the general rule, incorporation of hydrophilic HEMA makes the volume-phase-transition temperature shift to the lower temperature due to the strong intermolecular H-bonding between amide and -OH groups, -OH and -OH groups.
基金supported in part by International Platform for Dryland Research and Education (IPDRE),Tottori University
文摘In this study,wind tunnel experiment was carried out to investigate the self-staring capability for straight-bladed vertical axis wind turbine.The flow visualization also was been performed at the rest of the rotor.The effect of the azimuthal angle of blade position relative to wind direction on the self-starting capability was discussed based on the results of flow visualization.The torque and centripetal force of the rotor when the self-starting behavior starts were roughly calculated with the flow visualization results of the rotor.It is suggested that there exists the condition of wind speed and configuration of the blade position of the rotor at the rest of rotor to the reach to situational rotation number.
文摘A temperature-sensitive (ts) mutant of the CHO-K1 cell line, tsTM18, grows at 340C but not at 390C. Smu1 is the gene responsible for ts defects of tsTM18 cells. Previously, we found that the Smu1 ts defect altered the localization (as indicated by enlargement of speckles) of SRSF1 (SF2/ASF) in tsTM18 cells cultured at 390C, suggesting a functional association between Smu1 and SRSF1. Speckles are subnuclear structures that may function as storage/assembly/ modification compartments to supply splicing factors to active transcription sites. The effect of the ts defect of Smu1 on the localization of other factors related to splicing has not been characterized yet. The mechanisms underlying the enlargement of speckles of SRSF1 remain unclear. In the present study, we found that the ts defect of Smu1 affected the nuclear localization of a splicing factor, SRSF2 (SC35), and factors involved in the exon-exon junction complex, Y14 and ALY. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that the ts defect of Smu1 affected alternative splicing of endogenous Clk1/ Sty and SRSF2 genes. Mammalian Clk family kinases are shown to phosphorylate serine/arginine (SR) proteins in vitro and SRSF1 in vivo. RT-PCR analysis of Clk1/Sty showed an accumulation of the truncated form lacking kinase activity in tsTM18 cells incubated at 39?C. These data indicate that an accumulation of kinase-negative Clk1/Sty may lead to alteration of the localization of factors related to splicing resulting in the enlargement of speckles.
基金the National High Technology Research and Development Program(No.2016YFA0200303)the Beijing Natural Science Foundation(Nos.L172046,2192057)the National Natural Science Foundation of China(Nos.31771095,21875254 and 51573188)。
文摘Silk has been widely used in the clothing industry due to their soft and smooth features,good biocompatibility,good heat dissipation,warmth and ultraviolet resistance.The application of fragrance to silk can significantly improve the performance of silk.However,there are two key scientific problems that need to be solved:slowing down the release rate of fragrances and increasing the scent lasting time of silk.In this study,cationic and temperature-sensitive liposomes were designed and prepared to encapsulate eugenol.These fragrance-loaded liposomes significantly slowed down the release rate of the fragrance and controlled the release rate of the fragrance in a thermo-sensitive manner.The liposomes adhered to the silk through electrostatic adsorption interaction.The positive charge on the fragranceloaded liposomes neutralized much negative charge on silk and thereby increasing the adhesion efficiency.
文摘A kind of novel copolymer hydrogel of poly（N, N-dimethylaminoethyl methacrylate-co-N-isopropylacrylamide） （poly[DMAEMA/NIPAAm]） was synthesized by the initiation of K2S2O8, N, N＇-methylene-bis（acrylamide） （Bis） was used as the crosslinker. The effects of monomer content, pH and temperature on swelling ratio of the hydrogel were investigated; the thermo-sensitivity in deionized water and in physiological saline was determined. It showed that the swelling ratio of the hydrogel could be changed by changing the temperature or pH alternately. Both swelling ratio and LCST （Lower Critical Solution Temperature） of the hydrogel decreased with the increase of NIPAAm in the co-polymer content.
文摘The swelling behavior of a temperature-sensitive poly-N-isopropylacrylamide(PNIPAM) hydrogel circular cylinder is studied subjected to combined extension-torsion and varied temperature. In this regard, a semi-analytical solution is proposed for general combined loading. A finite element(FE) analysis is conducted, subjecting a hydrogel cylinder to the combined extension-torsion and the varied temperature to evaluate the validity and accuracy of the solution. A user-defined UHYPER subroutine is developed and verified under free and constrained swelling conditions. The FE results illustrate excellent agreement with the semi-analytical solution. Due to the complexity of the problem, some compositions and applied loading factors are analyzed. It is revealed that for larger cross-linked density and larger ending temperature, the cylinder yields higher stresses and smaller radial swelling deformation. Besides, the radial and hoop stresses increase by applying larger twist and axial stretch. The hoop stresses intersect at approximately R/Rout = 0.58, where the hoop stress vanishes. Besides, the axial force has direct and inverse relationships with the axial stretch and the twist, respectively. However, the resultant torsional moment behavior is complex, and the position of the maximum point varies significantly by altering the axial stretch and the twist.
基金financially supported by the National Natural Science Foun-dation of China(22278257)the Key R&D Program of Shaanxi Province(2024SF-YBXM-586)the Project of Innovation Capability Support Program in Shaanxi Province(2024ZC-KJXX-005)。
文摘Rapidly-advancing microneedle-based bioelectronics integrated with electrical stimulation(ES)therapy exhibit significant potential for improving chronic wound management.Herein,bio-inspired by the serrated structure of bee-stingers,we developed a temperature-sensitive,two-stage microneedle-based electro active platform(GP-PPy/PLA-MN)featuring rivet-like micros tructures that integrates intelligent,precise drug-releasing,ES-transmission,and real-time wound-assessment monitoring for comprehensive chronic wound-management and diagnostic therapy.The bionic-design mechanically anchors the microneedle beneath the skin's dermis,while GP-PPy/PLA-MN demonstrates versatile therapeutic characteristics,including outstanding biocompatibility,antimicrobial properties,and antimigratory origins.The GP-PPy/PLA-MN enables the sustained release of insulin at body temperature for up to24 hours through the poly-N-isopropyl acrylamide grafted amidated-gelatin-based thermo-sensitive hydrogel at the needle-tip,thereby providing long-term stable blood glucose control.GP-PPy/PLA-MN indicates its potential as a novel bioelectronics-based patch to record the temperature and humidity during the wound-healing process,realizing significant wound diagnosis and real-time wound assessment,and fundamentally facilitating the therapeutic efficacy by supplying solid data to protect the clinical practice.Extensive in vitro and in vivo studies have demonstrated that GP-PPy/PLA-MN can provide effective ES and sustained drug release,thereby promoting chronic wound healing and increasing the wound healing rate by 20%compared to the control group after 14 days of treatment.This innovative approach combines bioelectronics with intelligent drug delivery and microneedling technology to effectively address the critical challenges of chronic wound management,offering promising prospects for precision diagnostics and therapeutic interventions.
基金supported by the National Key Technology Research and Development Program of China(No.2016YFA0401200)the National Project for Research and Development of Major Scientific Instruments of China(No.11527802)the National Natural Science Foundation of China(Nos.91752102 and 11832018)。
文摘An experimental study on the boundary layer transition over a delta wing was carried out at Mach number 6 in a quiet wind tunnel.The Nano-tracer-based Planar Laser Scattering(NPLS)and Temperature-Sensitive Paints(TSP)techniques were used to measure the fine flow field structure and the wall Stanton number of the delta wing.The influence of factors such as the angle of attack and the Reynolds number was studied.The following results were obtained.The boundary layer transition between the leading edge and the centerline was dominated by the crossflow instability.At the location of the initial appearance of the traveling crossflow waves,the Stanton number began to rise.The Stanton number reached a maximum when the crossflow waves were broken up to turbulence.Increasing the angle of attack increased the spanwise pressure gradient at the windward side of the delta wing,thereby increasing the crossflow instability and advancing the boundary layer transition front.However,increasing the angle of attack caused the transition front to move backward at the leeward side.In addition,the sensitivity of the boundary layer transition to the Reynolds number varied with the angle of attack and the region.
基金support of Natural Sclenee Foundation of Zhejiang Province(No.LY19E030002)Ningbo Municipal Science and Technology Bureau(No.2019A610133)K.C.Wong Magna Fund in Ningbo University.
文摘Smart materials with a combination of tough solid-like properties,fast self-healing and optical responsiveness are of interests for the development of new soft machines and wearable electronics.In this work,tough physically cross-linked elastomers that show high mechanical strength,intriguing temperature-adaptable self-healing and fluorochromic response properties are designed using aluminum(Al)and fluorescent europium(Eu)ions as cross-linkers.The ionic Al-COOH binding is incorporated to construct the strong polymer network which mainly contributes to the mechanical robustness of the elastomer consisting of two interpenetrated networks.The Eu-iminodiacetate(IDA)coordination is mainly used to build the weaker but more dynamic network which dominate the elasticity,self-healing and luminescence of the elastomer.Moderate Eu^(3+) and Al^(3+) contents give these supramolecular elastomers high toughness.The temperature-sensitive Eu-IDA coordination enables tunable self-healing rate and efficiency along with fast Eu-centered"ON/OFF"switchable red emission.The mechanical,self-healing and luminescence properties of these elastomers can be adjusted by tuning the ratio of the two types of metal ions.This elastomer is potentially applicable for biosensors,wearable optoelectronics and anticounterfeiting materials.
基金support from the National Natural Science Foundation of China (20874013)
文摘A novel method for the synthesis of macrocyclic graft copolymers was developed through combination of anionic ring-opening polymerization (AROP) and atom transfer radical polymerization (ATRP).A linear α,ω-dihydroxyl poly(ethylene oxide) with pendant acetal protected hydroxyl groups (l-poly(EO-co-EEGE)) was prepared first by the anionic copolymerization of ethylene oxide (EO) and ethoxyethyl glycidyl ether (EEGE).Then l-poly(EO-co-EEGE) was cyclized.The crude cyclized product containing the linear byproduct was hydrolyzed and purified by being treated with α-CD.The pure cyclic copolymer [c-poly(EO-co-Gly)] was esterified by reaction with 2-bromoisobutyryl bromide,and then used as ATRP macroinitiators to initiate polymerization of 2-(dimethylamino) ethyl methacrylate (DMAEMA),and a series of pH-and temperature-sensitive macrocyclic graft copolymers composed of a hydrophilic PEO as the ring and PDMAEMA as side chains (c-PEO-g-PDMAEMA) were obtained.The behavior of pH-and temperature-sensitive macrocyclic copolymers was studied in aqueous solution by fluorescence and dynamic light scattering (DLS).The critical micellization pH values of macrocyclic graft copolymers and their corresponding linear graft copolymers (l-PEO-g-PDMAEMA) were measured.Under the same conditions,the cyclic graft copolymer with the shorter side chains gave the higher critical micellization pH value.The c-PEO-g-PDMAEMA showed the lower critical micellization pH value than the corresponding l-PEO-g-PDMAEMA.The average hydrodynamic diameters (Dh) of the micelles were measured by DLS with the variation of the aqueous solution pH value and temperature.
基金This work was supported by National Natural Science Foundation of China （No. 21375123） and The Ministry of Science and Technology of China （No. 216YFA0203201）.
文摘For the first time, we are reporting a novel type of dual fluorescence temperaturesensitive DNA-templated silver nanocluster （AgNC） pair, which contains two pieces of single-stranded AgNC in proximity through hybridization. Both the chameleon AgNC pairs, A-NCP and B-NCP, possess two bright fluorescence peaks that achieve sensitive variations corresponding to temperature change from 15 to 45 ℃. With the increase in temperature, one of the fluorescence emissions of A-NCP （A-FL570） increases, while the other （A-FL640） decreases. However, both the emissions of B-NCP （B-FL685 and B-FL620） decrease simultaneously. Therefore, A-NCP shows a remarkable fluorescence color variation from orange to yellow, while the fluorescence color of B-NCP changes from orange to colorless, with increase in temperature. Moreover, the temperature responding linear range of A-NCP can be regulated by adjusting the structures and sequences of assistant DNA templates. It is assumed that the two single-stranded segmental AgNCs are integrated together as they are assembled into AgNC pairs, leading to a dramatic variation in fluorescence properties. The temperature-sensitive phenomenon is due to the dehybridization-induced separation of two pieces of segmental AgNC, caused by temperature increase. The temperature-sensitive AgNC pairs have been successful in indicating the temperature of living cells, showing the potential for a new application of silver nanocluster as a nanothermometer with adjustable response range, bringing novel insight into the regulatory mechanism of AgNC fluorescence variation.
