Neurotrophic keratopathy is a persistent defect of the corneal epithelium,with or without stromal ulceration,due to corneal nerve deficiency caused by a variety of etiologies.The treatment options for neurotrophic ker...Neurotrophic keratopathy is a persistent defect of the corneal epithelium,with or without stromal ulceration,due to corneal nerve deficiency caused by a variety of etiologies.The treatment options for neurotrophic keratopathy are limited.In this study,an ophthalmic solution was constructed from a chitosan-based thermosensitive hydrogel with long-term release of murine nerve growth factor(CTH-mNGF).Its effectiveness was evaluated in corneal denervation(CD)mice and patients with neurotrophic keratopathy.In the preclinical setting,CTH-mNGF was assessed in a murine corneal denervation model.CTH-mNGF was transparent,thermosensitive,and ensured sustained release of mNGF for over 20 hours on the ocular surface,maintaining the local mNGF concentration around 1300 pg/mL in vivo.Corneal denervation mice treated with CTH-mNGF for 10 days showed a significant increase in corneal nerve area and total corneal nerve length compared with non-treated and CTH treated mice.A subsequent clinical trial of CTH-mNGF was conducted in patients with stage 2 or 3 neurotrophic keratopathy.Patients received topical CTH-mNGF twice daily for 8 weeks.Fluorescein sodium images,Schirmer’s test,intraocular pressure,Cochet-Bonnet corneal perception test,and best corrected visual acuity were evaluated.In total,six patients(total of seven eyes)diagnosed with neurotrophic keratopathy were enrolled.After 8 weeks of CTH-mNGF treatment,all participants showed a decreased area of corneal epithelial defect,as stained by fluorescence.Overall,six out of seven eyes had fluorescence staining scores<5.Moreover,best corrected visual acuity,intraocular pressure,Schirmer’s test and Cochet-Bonnet corneal perception test results showed no significant improvement.An increase in corneal nerve density was observed by in vivo confocal microscopy after 8 weeks of CTH-mNGF treatment in three out of seven eyes.This study demonstrates that CTH-mNGF is transparent,thermosensitive,and has sustained-release properties.Its effectiveness in healing corneal epithelial defects in all eyes with neurotrophic keratopathy suggests CTH-mNGF has promising application prospects in the treatment of neurotrophic keratopathy,being convenient and cost effective.展开更多
objective:To Investigate the preparation,dissolution and release in vitro of thermosensitive in situ gel of iodine.Methods:Using orthogonal test method for screening the best prescription;Using the formula of gel accu...objective:To Investigate the preparation,dissolution and release in vitro of thermosensitive in situ gel of iodine.Methods:Using orthogonal test method for screening the best prescription;Using the formula of gel accumulative dissolution percentage=(W1-Wt)/(W1-W0)to calculate the dissolution rate of Q by membrane-free;Calculating the accumulative release rate by the standard curve.As time increases,the dissolution rate and the release rate of the gel increased significantly.Conclusion:Thermosensitive in situ gel of iodine has good sustained release effect.展开更多
Thermosensitive liposomes(TSLs) have been an important research area in the field of tumor targeted chemotherapy. Since the first TSLs appeared that using 1,2-dipalmitoyl-snglyce-ro-3-phosphocholine(DPPC) as the prima...Thermosensitive liposomes(TSLs) have been an important research area in the field of tumor targeted chemotherapy. Since the first TSLs appeared that using 1,2-dipalmitoyl-snglyce-ro-3-phosphocholine(DPPC) as the primary liposomal lipid, many studies have been done using this type of liposome from basic and practical aspects. While TSLs composed of DPPC enhance the cargo release near the phase transition temperature, it has been shown that many factors affect their temperature sensitivity. Thus numerous attempts have been undertaken to develop new TSLs for improving their thermal response performance. The main objective of this review is to introduce the development and recent update of innovative TSLs formulations, including combination of radiofrequency ablation(RFA), highintensity focused ultrasound(HIFU), magnetic resonance imaging(MRI) and alternating magnetic field(AMF). In addition, various factors affecting the design of TSLs, such as lipid composition, surfactant, size and serum components are also discussed.展开更多
The in situ gelling hybrid hydrogel system has been reported to effectively concentratechemotherapeutic drugs at the tumor site and sustain their release for a long period. DTX-micelles(docetaxel-loaded mixed micelles...The in situ gelling hybrid hydrogel system has been reported to effectively concentratechemotherapeutic drugs at the tumor site and sustain their release for a long period. DTX-micelles(docetaxel-loaded mixed micelles) are able to increase the solubility of DTX inwater, and then a high drug loading rate of hydrogels can be achieved by encapsulatingthe docetaxel-loaded mixed micelles into the hydrogels. The thermosensitive nature ofDTX-MM-hydrogels(thermosensitive hydrogels incorporated with docetaxel-loaded mixedmicelles) can accelerate the formation of a depot of this drug-loaded system at the siteof administration. Therefore, the hydrogels provide a much slower release compared withDTX-micelles and DTX-injection. An in vivo retention study has demonstrated that the DTX-MM-hydrogels can prolong the drug retention time and in viv o trials have shown that theDTX-MM-hydrogels have a higher antitumor efficacy and systemic safety. In conclusion, theDTX-MM-hydrogels prepared in this study have considerable potential as a drug deliverysystem, with higher tumor inhibition effects and are less toxic to normal tissues.展开更多
Tissue engineering technologies offer new treatment strategies for the repair of peripheral nerve injury, hut cell loss between seeding and adhesion to the scaffold remains inevitable. A thermosensitive collagen hydro...Tissue engineering technologies offer new treatment strategies for the repair of peripheral nerve injury, hut cell loss between seeding and adhesion to the scaffold remains inevitable. A thermosensitive collagen hydrogel was used as an extracellular matrix in this study and combined with bone marrow mesenchymal stem cells to construct tissue-engineered peripheral nerve composites in vitro. Dynamic culture was performed at an oscillating frequency of 0.5 Hz and 35° swing angle above and below the horizontal plane. The results demonstrated that bone marrow mesenchymal stem cells formed membrane-like structures around the poly-L-lactic acid scaffolds and exhibited regular alignment on the composite surface. Collagen was used to fill in the pores, and seeded cells adhered onto the poly-L-lactic acid fibers. The DNA content of the bone marrow mesenchymal stem cells was higher in the composites constructed with a thermosensitive collagen hydrogel compared with that in collagen I scaffold controls. The cellular DNA content was also higher in the thermosensitive collagen hydrogel composites constructed with the thermosensitive collagen hydrogel in dynamic culture than that in static culture. These results indicate that tissue-engineered composites formed with thermosensitive collagen hydrogel in dynamic culture can maintain larger numbers of seeded cells by avoiding cell loss during the initial adhe-sion stage. Moreover, seeded cells were distributed throughout the material.展开更多
A feasible neuron model can be effective to estimate the mode transition in neural activities in a complex electromagnetic environment.When neurons are exposed to electromagnetic field,the continuous magnetization and...A feasible neuron model can be effective to estimate the mode transition in neural activities in a complex electromagnetic environment.When neurons are exposed to electromagnetic field,the continuous magnetization and polarization can generate nonlinear effect on the exchange and propagation of ions in the cell,and then the firing patterns can be regulated completely.The conductivity of ion channels can be affected by the temperature and the channel current is adjusted for regulating the excitability of neurons.In this paper,a phototube and a thermistor are used to the functions of neural circuit.The phototube is used to capture external illumination for energy injection,and a continuous signal source is obtained.The thermistor is used to percept the changes of temperature,and the channel current is changed to adjust the excitability of neuron.This functional neural circuit can encode the external heat(temperature)and illumination excitation,and the dynamics of neural activities is investigated in detail.The photocurrent generated in the phototube can be used as a signal source for the neural circuit,and the thermistor is used to estimate the conduction dependence on the temperature for neurons under heat effect.Bifurcation analysis and Hamilton energy are calculated to explore the mode selection.It is found that complete dynamical properties of biological neurons can be reproduced in spiking,bursting,and chaotic firing when the phototube is activated as voltage source.The functional neural circuit mainly presents spiking states when the photocurrent is handled as a stable current source.Gaussian white noise is imposed to detect the occurrence of coherence resonance.This neural circuit can provide possible guidance for investigating dynamics of neural networks and potential application in designing sensitive sensors.展开更多
Long-term injectable microspheres have some inherent disadvantages such as migration of micro- spheres from the original site and the burst effect.In order to avoid these problems,microsphere-loaded thermosen- sitive ...Long-term injectable microspheres have some inherent disadvantages such as migration of micro- spheres from the original site and the burst effect.In order to avoid these problems,microsphere-loaded thermosen- sitive hydrogel system was designed and expected to achieve a zero-order release of biomolecular drugs in relative high initial drug loadings.Lysozyme,an antibacterial protein usually used to reduce prosthetic valve endocarditis, was selected as the model drug.Poly(DL-lactide-co-glycolide)(PLGA)microspheres,prepared by solvent evapo- ration method,were employed to encapsulate lysozyme and dispersed into thermosensitive pre-gel solution con- taining methylcellulose(MC),polyethylene glycol(PEG),sodium citrate(SC),and sodium alginate(SA).The mix- ture could act as a drug reservoir by performing sol-gel transition rapidly if the temperature was raised from room temperature to 37℃.The in vitro release results showed that the burst effect was avoided due to strengthening of diffusion resistance in the gel.The formulation was able to deliver lysozyme for over 30 days in a nearly zero-order release profile with a rate of 32.8μg.d -1 which exhibits its remarkable potential for effective application in long-term drug delivery.展开更多
It was tried to prepare the thermosensitive microcapsules containing the water soluble solid powder by the melting dispersion cooling method and to establish the optimum preparation conditions. As a model water solubl...It was tried to prepare the thermosensitive microcapsules containing the water soluble solid powder by the melting dispersion cooling method and to establish the optimum preparation conditions. As a model water soluble solid powder, sodium hydrogen carbonate was adopted in order to generate carbon dioxide gas and as a thermosensitive shell material, olefin resin with the melting point of ca. 40°C was used. In the experiment, the concentration of olefin resin in the shell material solution was mainly changed together with the concentrations of the oil soluble surfactant species and the α-tocopherol as a modifier of shell. Addition of α-tocopherol into the shell material solution could prevent the core from breaking away during the microencapsulation process and result in the higher microencapsulation efficiency, because the dispersion stability of solid powder in the shell material solution could be increased due to the increase in affinity between the shell material solution and solid powder. Also, the microencapsulation efficiency increased with the concentration of olefin resin, became maximum at 50 wt% and then, decreased. The microcapsules were found to begin melting at 36°C and to generate carbon dioxide gas.展开更多
Two novel biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups were synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene) with the ...Two novel biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups were synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene) with the sodium salt of lactic acid ester and sodium methoxyethoxyethoxide.Their structures were confirmed by ^(31)p NMR,~1H NMR,^(13)C NMR,IR,DSC,and elemental analysis.The lower critical solution temperature(LCST) behavior in water and in vitro degradation property of the polymers was investigated.The...展开更多
The chitosan/β-glycerophosphate( CS/β-GP),a physical hydrogel system with thermosensitive and injectable features combined with biocompatibility and biodegradability, has great potentials as matrices for drug or cel...The chitosan/β-glycerophosphate( CS/β-GP),a physical hydrogel system with thermosensitive and injectable features combined with biocompatibility and biodegradability, has great potentials as matrices for drug or cell encapsulation and delivery,or as in situ gel-forming materials for tissue repair. Here,the chitin nanocrystal( Chi NC) was introduced into the aforementioned system, and its effects on solution behavior and mechanical properties was investigated. The results showed the incorporation of Chi NC complicated sol-to-gel transition process; a higher loading ratio( 20%) speeded up sol-to-gel transition rate,reduced the solto-gel transition temperature,while still maintained shear-thinning behavior or injectable feature. Moreover,the mechanical properties of gels were significantly enhanced by Chi NC, accompanied by decreased water uptake. The above mentioned behavior favored better applications as injectable tissue-repair implants.展开更多
Temperature has distinct influence on the activation of ion channels and the excitability of neurons,and careful change in temperature can induce possible mode transition in the neural activities.The formation and dev...Temperature has distinct influence on the activation of ion channels and the excitability of neurons,and careful change in temperature can induce possible mode transition in the neural activities.The formation and development of autapse connection to neuron can enhance its self-adaption to external stimulus,and thus the firing patterns in neuron can be controlled effectively.The autapse is activated to drive a thermosensitive neuron,which is developed from the FitzHugh-Nagumo neural circuit by incorporating a thermistor,and the dynamics in the neural activities is explored to find mode dependence on the temperature and autaptic current.It is found that the firing modes can be controlled by temperature,and the neuron is wakened from resting state to periodic oscillation with the increase of temperature.Furthermore,the intensity and the intrinsic time delay in the autapse are respectively adjusted to control the neural activities,and it is confirmed that appropriate setting for autaptic current can balance and enhance the temperature effect on the neural activities.展开更多
Astrocytes have a regulatory function on the central nervous system(CNS), especially in the temperature-sensitive hippocampal region. In order to explore the thermosensitive dynamic mechanism of astrocytes in the CNS,...Astrocytes have a regulatory function on the central nervous system(CNS), especially in the temperature-sensitive hippocampal region. In order to explore the thermosensitive dynamic mechanism of astrocytes in the CNS, we establish a neuron-astrocyte minimum system to analyze the synchronization change characteristics based on the Hodgkin-Huxley model, in which a pyramidal cell and an interneuron are connected by an astrocyte. The temperature range is set as 0-40 ℃ to juggle between theoretical calculation and the reality of a brain environment. It is shown that the synchronization of thermosensitive neurons exhibits nonlinear behavior with changes in astrocyte parameters. At a temperature range of0 ℃-18 ℃, the effects of the astrocyte can provide a tremendous influence on neurons in synchronization. We find the existence of a value for inositol triphosphate(IP_(3)) production rate and feedback intensities of astrocytes to neurons, which can ensure the weak synchronization of two neurons. In addition, it is revealed that the regulation of astrocytes to pyramidal cells is more sensitive than that to interneurons. Finally, it is shown that the synchronization and phase transition of neurons depend on the change in Ca^(2+) concentration at the temperature of weak synchronization. The results in this paper provide some enlightenment on the mechanism of cognitive dysfunction and neurological disorders with astrocytes.展开更多
In this study, the effect of silica/calcium phosphate (SiCaP) nanocomposite particles on the properties of a novel chitosan-based thermosensitive hydrogel system was examined. SiCaP nanocomposite powder was fabricated...In this study, the effect of silica/calcium phosphate (SiCaP) nanocomposite particles on the properties of a novel chitosan-based thermosensitive hydrogel system was examined. SiCaP nanocomposite powder was fabricated using a sol-gel method and then used to fabricate nanocomposite hydrogels (Ch- <em>β</em>/7.5SiCaP and Ch-<em>β</em>/15SiCaP) including chitosan and <em>β</em>-glycerophosphate (Ch-<em>β</em>) as a matrix. Results revealed that compared to the Ch-<em>β </em>hydrogel without SiCaP, the presence of SiCaP particles in nanocomposite hydrogels maintained pH stability during the sol-gel transition, accelerated the gelation and improved the stiffness of nanocomposite hydrogels. Gelation time at 37℃ was reduced approximately 75% and stiffness was increased approximately 115%. Both of these changes are attributed to chemical and physical interactions of the SiCaP bioactive particles with chitosan. Furthermore, compared to the Ch-<em>β</em> hydrogel, the presence of SiCaP in the Ch-<em>β</em>/7.5SiCaP nanocomposite hydrogel did not affect biocompatibility negatively, but improved osteoblastic cell differentiation. Our studies suggest that these nanocomposite hydrogels may offer an innovative approach to bone regeneration strategies.展开更多
Thermosensitive genic male sterility(TGMS)has been widely used in two-line hybrid rice breeding.Due to hybrid seed production being highly affected by changeable environments,its application scope is limited to some e...Thermosensitive genic male sterility(TGMS)has been widely used in two-line hybrid rice breeding.Due to hybrid seed production being highly affected by changeable environments,its application scope is limited to some extent.Thus,it is of great importance to identify potential TGMS genes in specific rice varieties.Here,Diannong S-1 xuan(DNS-1 X),a reverse TGMS(RTGMS)japonica male sterile line,was identified from Diannong S-1.Genetic analysis showed that male sterility was tightly controlled by a single recessive gene,which was supported by the phenotype of the F;and F;populations derived from the cross between DNS-1 X and Yunjing 26(YJ26).Combining simple sequence repeat(SSR)markers and bulked segregation analysis(BSA),we identified a 215 kb region on chromosome 10 as a candidate reverse TGMS region,which was designated as rtmsl-D.It was narrower than the previously reported RTGMS genes rtmsl and tms6(t).The fertility conversion detected in the natural environment showed that DNS-1 X was sterile below 28-30℃;otherwise,it was fertile.Histological analysis further indicated that the pollen abortion was occurred in the young microspore stage.This study will provide new resources for two-line hybrid rice and pave the way for molecular breeding of RTGMS lines.展开更多
The Cu-based thermosensitive nanocomposites are made by high energy ball milling. The microstructures and properties of Cu-based thermosensitive nanocomposites are studied by transmission electron microscopy(TEM) and ...The Cu-based thermosensitive nanocomposites are made by high energy ball milling. The microstructures and properties of Cu-based thermosensitive nanocomposites are studied by transmission electron microscopy(TEM) and themosensitivity test. The effects of milling time on the microstructures and the thermosensitivity of Cu-based nanocomposite material are researched. The results show that the Cu-based nanocomposite can be made by high energy ball milling. As the milling time increases, the copper particle size decreases in the nanocomposite, then the thermoexpansivity of nanocomposite increases. The nanocomposite is of best thermoexpansivity when the milling time is up to 100 h. At 35- 45 ℃, the nanocomposite shows good thermosensitivity.展开更多
A color image formation method is p re sented with thermosensitive liquid crystal polymers. The liquid crystal polymers are capable of reversibly assuming optical states of transparent and scattering lights, and allow...A color image formation method is p re sented with thermosensitive liquid crystal polymers. The liquid crystal polymers are capable of reversibly assuming optical states of transparent and scattering lights, and allow picture-element display areas in two colors at least to be co mposed on a surface. The picture elements within color areas are selected if they correspond to the color which is the spectral transmission center. A heat is applied such that the maximum haze degree of the selected picture elements is greater than that of picture elements corresponding to any of the other colo rs.展开更多
基金supported by PLA General Hospital Program,No.LB20201A010024(to LW).
文摘Neurotrophic keratopathy is a persistent defect of the corneal epithelium,with or without stromal ulceration,due to corneal nerve deficiency caused by a variety of etiologies.The treatment options for neurotrophic keratopathy are limited.In this study,an ophthalmic solution was constructed from a chitosan-based thermosensitive hydrogel with long-term release of murine nerve growth factor(CTH-mNGF).Its effectiveness was evaluated in corneal denervation(CD)mice and patients with neurotrophic keratopathy.In the preclinical setting,CTH-mNGF was assessed in a murine corneal denervation model.CTH-mNGF was transparent,thermosensitive,and ensured sustained release of mNGF for over 20 hours on the ocular surface,maintaining the local mNGF concentration around 1300 pg/mL in vivo.Corneal denervation mice treated with CTH-mNGF for 10 days showed a significant increase in corneal nerve area and total corneal nerve length compared with non-treated and CTH treated mice.A subsequent clinical trial of CTH-mNGF was conducted in patients with stage 2 or 3 neurotrophic keratopathy.Patients received topical CTH-mNGF twice daily for 8 weeks.Fluorescein sodium images,Schirmer’s test,intraocular pressure,Cochet-Bonnet corneal perception test,and best corrected visual acuity were evaluated.In total,six patients(total of seven eyes)diagnosed with neurotrophic keratopathy were enrolled.After 8 weeks of CTH-mNGF treatment,all participants showed a decreased area of corneal epithelial defect,as stained by fluorescence.Overall,six out of seven eyes had fluorescence staining scores<5.Moreover,best corrected visual acuity,intraocular pressure,Schirmer’s test and Cochet-Bonnet corneal perception test results showed no significant improvement.An increase in corneal nerve density was observed by in vivo confocal microscopy after 8 weeks of CTH-mNGF treatment in three out of seven eyes.This study demonstrates that CTH-mNGF is transparent,thermosensitive,and has sustained-release properties.Its effectiveness in healing corneal epithelial defects in all eyes with neurotrophic keratopathy suggests CTH-mNGF has promising application prospects in the treatment of neurotrophic keratopathy,being convenient and cost effective.
文摘objective:To Investigate the preparation,dissolution and release in vitro of thermosensitive in situ gel of iodine.Methods:Using orthogonal test method for screening the best prescription;Using the formula of gel accumulative dissolution percentage=(W1-Wt)/(W1-W0)to calculate the dissolution rate of Q by membrane-free;Calculating the accumulative release rate by the standard curve.As time increases,the dissolution rate and the release rate of the gel increased significantly.Conclusion:Thermosensitive in situ gel of iodine has good sustained release effect.
基金National Natural Science Foundation of China (No.31671020) for financial support
文摘Thermosensitive liposomes(TSLs) have been an important research area in the field of tumor targeted chemotherapy. Since the first TSLs appeared that using 1,2-dipalmitoyl-snglyce-ro-3-phosphocholine(DPPC) as the primary liposomal lipid, many studies have been done using this type of liposome from basic and practical aspects. While TSLs composed of DPPC enhance the cargo release near the phase transition temperature, it has been shown that many factors affect their temperature sensitivity. Thus numerous attempts have been undertaken to develop new TSLs for improving their thermal response performance. The main objective of this review is to introduce the development and recent update of innovative TSLs formulations, including combination of radiofrequency ablation(RFA), highintensity focused ultrasound(HIFU), magnetic resonance imaging(MRI) and alternating magnetic field(AMF). In addition, various factors affecting the design of TSLs, such as lipid composition, surfactant, size and serum components are also discussed.
基金financial support to the National Natural Science Foundation of China (81202480,81302723 )the Natural Science Foundation of Liaoning Province (2015020749)+1 种基金the Innovative training program for college students (201710163000080)support of the Pharmacology Laboratory Centre and the Animal Centre of Shenyang Pharmaceutical University
文摘The in situ gelling hybrid hydrogel system has been reported to effectively concentratechemotherapeutic drugs at the tumor site and sustain their release for a long period. DTX-micelles(docetaxel-loaded mixed micelles) are able to increase the solubility of DTX inwater, and then a high drug loading rate of hydrogels can be achieved by encapsulatingthe docetaxel-loaded mixed micelles into the hydrogels. The thermosensitive nature ofDTX-MM-hydrogels(thermosensitive hydrogels incorporated with docetaxel-loaded mixedmicelles) can accelerate the formation of a depot of this drug-loaded system at the siteof administration. Therefore, the hydrogels provide a much slower release compared withDTX-micelles and DTX-injection. An in vivo retention study has demonstrated that the DTX-MM-hydrogels can prolong the drug retention time and in viv o trials have shown that theDTX-MM-hydrogels have a higher antitumor efficacy and systemic safety. In conclusion, theDTX-MM-hydrogels prepared in this study have considerable potential as a drug deliverysystem, with higher tumor inhibition effects and are less toxic to normal tissues.
基金supported by the National Natural Science Foundation of China,No.31071222Jilin Province Science and Technology Development Project in China,No.20080738the Frontier Interdiscipline Program of Norman Bethune Health Science Center of Jilin University in China,No.2013106023
文摘Tissue engineering technologies offer new treatment strategies for the repair of peripheral nerve injury, hut cell loss between seeding and adhesion to the scaffold remains inevitable. A thermosensitive collagen hydrogel was used as an extracellular matrix in this study and combined with bone marrow mesenchymal stem cells to construct tissue-engineered peripheral nerve composites in vitro. Dynamic culture was performed at an oscillating frequency of 0.5 Hz and 35° swing angle above and below the horizontal plane. The results demonstrated that bone marrow mesenchymal stem cells formed membrane-like structures around the poly-L-lactic acid scaffolds and exhibited regular alignment on the composite surface. Collagen was used to fill in the pores, and seeded cells adhered onto the poly-L-lactic acid fibers. The DNA content of the bone marrow mesenchymal stem cells was higher in the composites constructed with a thermosensitive collagen hydrogel compared with that in collagen I scaffold controls. The cellular DNA content was also higher in the thermosensitive collagen hydrogel composites constructed with the thermosensitive collagen hydrogel in dynamic culture than that in static culture. These results indicate that tissue-engineered composites formed with thermosensitive collagen hydrogel in dynamic culture can maintain larger numbers of seeded cells by avoiding cell loss during the initial adhe-sion stage. Moreover, seeded cells were distributed throughout the material.
基金Project supported by the National Natural Science Foundation of China(Grant No.11672122).
文摘A feasible neuron model can be effective to estimate the mode transition in neural activities in a complex electromagnetic environment.When neurons are exposed to electromagnetic field,the continuous magnetization and polarization can generate nonlinear effect on the exchange and propagation of ions in the cell,and then the firing patterns can be regulated completely.The conductivity of ion channels can be affected by the temperature and the channel current is adjusted for regulating the excitability of neurons.In this paper,a phototube and a thermistor are used to the functions of neural circuit.The phototube is used to capture external illumination for energy injection,and a continuous signal source is obtained.The thermistor is used to percept the changes of temperature,and the channel current is changed to adjust the excitability of neuron.This functional neural circuit can encode the external heat(temperature)and illumination excitation,and the dynamics of neural activities is investigated in detail.The photocurrent generated in the phototube can be used as a signal source for the neural circuit,and the thermistor is used to estimate the conduction dependence on the temperature for neurons under heat effect.Bifurcation analysis and Hamilton energy are calculated to explore the mode selection.It is found that complete dynamical properties of biological neurons can be reproduced in spiking,bursting,and chaotic firing when the phototube is activated as voltage source.The functional neural circuit mainly presents spiking states when the photocurrent is handled as a stable current source.Gaussian white noise is imposed to detect the occurrence of coherence resonance.This neural circuit can provide possible guidance for investigating dynamics of neural networks and potential application in designing sensitive sensors.
基金Supported by the National Natural Science Foundation of China (No.20576057) and Fundamental Research Foundation of Tsinghua University (JCqn2005033).
文摘Long-term injectable microspheres have some inherent disadvantages such as migration of micro- spheres from the original site and the burst effect.In order to avoid these problems,microsphere-loaded thermosen- sitive hydrogel system was designed and expected to achieve a zero-order release of biomolecular drugs in relative high initial drug loadings.Lysozyme,an antibacterial protein usually used to reduce prosthetic valve endocarditis, was selected as the model drug.Poly(DL-lactide-co-glycolide)(PLGA)microspheres,prepared by solvent evapo- ration method,were employed to encapsulate lysozyme and dispersed into thermosensitive pre-gel solution con- taining methylcellulose(MC),polyethylene glycol(PEG),sodium citrate(SC),and sodium alginate(SA).The mix- ture could act as a drug reservoir by performing sol-gel transition rapidly if the temperature was raised from room temperature to 37℃.The in vitro release results showed that the burst effect was avoided due to strengthening of diffusion resistance in the gel.The formulation was able to deliver lysozyme for over 30 days in a nearly zero-order release profile with a rate of 32.8μg.d -1 which exhibits its remarkable potential for effective application in long-term drug delivery.
文摘It was tried to prepare the thermosensitive microcapsules containing the water soluble solid powder by the melting dispersion cooling method and to establish the optimum preparation conditions. As a model water soluble solid powder, sodium hydrogen carbonate was adopted in order to generate carbon dioxide gas and as a thermosensitive shell material, olefin resin with the melting point of ca. 40°C was used. In the experiment, the concentration of olefin resin in the shell material solution was mainly changed together with the concentrations of the oil soluble surfactant species and the α-tocopherol as a modifier of shell. Addition of α-tocopherol into the shell material solution could prevent the core from breaking away during the microencapsulation process and result in the higher microencapsulation efficiency, because the dispersion stability of solid powder in the shell material solution could be increased due to the increase in affinity between the shell material solution and solid powder. Also, the microencapsulation efficiency increased with the concentration of olefin resin, became maximum at 50 wt% and then, decreased. The microcapsules were found to begin melting at 36°C and to generate carbon dioxide gas.
基金the National Natural Foundation of China(No. 20364002)the Natural Science Foundation of Yunnan Province(No.2005B0027 M),China
文摘Two novel biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups were synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene) with the sodium salt of lactic acid ester and sodium methoxyethoxyethoxide.Their structures were confirmed by ^(31)p NMR,~1H NMR,^(13)C NMR,IR,DSC,and elemental analysis.The lower critical solution temperature(LCST) behavior in water and in vitro degradation property of the polymers was investigated.The...
基金National Natural Science Foundation of China(No.51303024)
文摘The chitosan/β-glycerophosphate( CS/β-GP),a physical hydrogel system with thermosensitive and injectable features combined with biocompatibility and biodegradability, has great potentials as matrices for drug or cell encapsulation and delivery,or as in situ gel-forming materials for tissue repair. Here,the chitin nanocrystal( Chi NC) was introduced into the aforementioned system, and its effects on solution behavior and mechanical properties was investigated. The results showed the incorporation of Chi NC complicated sol-to-gel transition process; a higher loading ratio( 20%) speeded up sol-to-gel transition rate,reduced the solto-gel transition temperature,while still maintained shear-thinning behavior or injectable feature. Moreover,the mechanical properties of gels were significantly enhanced by Chi NC, accompanied by decreased water uptake. The above mentioned behavior favored better applications as injectable tissue-repair implants.
基金supported by the National Natural Science Foundation of China(Grant Nos.12072139 and 12062009).
文摘Temperature has distinct influence on the activation of ion channels and the excitability of neurons,and careful change in temperature can induce possible mode transition in the neural activities.The formation and development of autapse connection to neuron can enhance its self-adaption to external stimulus,and thus the firing patterns in neuron can be controlled effectively.The autapse is activated to drive a thermosensitive neuron,which is developed from the FitzHugh-Nagumo neural circuit by incorporating a thermistor,and the dynamics in the neural activities is explored to find mode dependence on the temperature and autaptic current.It is found that the firing modes can be controlled by temperature,and the neuron is wakened from resting state to periodic oscillation with the increase of temperature.Furthermore,the intensity and the intrinsic time delay in the autapse are respectively adjusted to control the neural activities,and it is confirmed that appropriate setting for autaptic current can balance and enhance the temperature effect on the neural activities.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 51607056, 51737003, and 51877069)State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology (Grant No. EERI PI2020006)。
文摘Astrocytes have a regulatory function on the central nervous system(CNS), especially in the temperature-sensitive hippocampal region. In order to explore the thermosensitive dynamic mechanism of astrocytes in the CNS, we establish a neuron-astrocyte minimum system to analyze the synchronization change characteristics based on the Hodgkin-Huxley model, in which a pyramidal cell and an interneuron are connected by an astrocyte. The temperature range is set as 0-40 ℃ to juggle between theoretical calculation and the reality of a brain environment. It is shown that the synchronization of thermosensitive neurons exhibits nonlinear behavior with changes in astrocyte parameters. At a temperature range of0 ℃-18 ℃, the effects of the astrocyte can provide a tremendous influence on neurons in synchronization. We find the existence of a value for inositol triphosphate(IP_(3)) production rate and feedback intensities of astrocytes to neurons, which can ensure the weak synchronization of two neurons. In addition, it is revealed that the regulation of astrocytes to pyramidal cells is more sensitive than that to interneurons. Finally, it is shown that the synchronization and phase transition of neurons depend on the change in Ca^(2+) concentration at the temperature of weak synchronization. The results in this paper provide some enlightenment on the mechanism of cognitive dysfunction and neurological disorders with astrocytes.
文摘In this study, the effect of silica/calcium phosphate (SiCaP) nanocomposite particles on the properties of a novel chitosan-based thermosensitive hydrogel system was examined. SiCaP nanocomposite powder was fabricated using a sol-gel method and then used to fabricate nanocomposite hydrogels (Ch- <em>β</em>/7.5SiCaP and Ch-<em>β</em>/15SiCaP) including chitosan and <em>β</em>-glycerophosphate (Ch-<em>β</em>) as a matrix. Results revealed that compared to the Ch-<em>β </em>hydrogel without SiCaP, the presence of SiCaP particles in nanocomposite hydrogels maintained pH stability during the sol-gel transition, accelerated the gelation and improved the stiffness of nanocomposite hydrogels. Gelation time at 37℃ was reduced approximately 75% and stiffness was increased approximately 115%. Both of these changes are attributed to chemical and physical interactions of the SiCaP bioactive particles with chitosan. Furthermore, compared to the Ch-<em>β</em> hydrogel, the presence of SiCaP in the Ch-<em>β</em>/7.5SiCaP nanocomposite hydrogel did not affect biocompatibility negatively, but improved osteoblastic cell differentiation. Our studies suggest that these nanocomposite hydrogels may offer an innovative approach to bone regeneration strategies.
基金financially Science and technology projects of Yunnan Province,China(Grant No.202003AD150007)Strategic Leading Science and Technology Programme of Chinese Academy of Sciences(Grant Nos.XDA24030301 and XDA24040308)+1 种基金Natural Science Foundation of Yunnan,China(Grant No.2018FA 023)National Natural Science Foundation of China(Grant No.31902110)。
文摘Thermosensitive genic male sterility(TGMS)has been widely used in two-line hybrid rice breeding.Due to hybrid seed production being highly affected by changeable environments,its application scope is limited to some extent.Thus,it is of great importance to identify potential TGMS genes in specific rice varieties.Here,Diannong S-1 xuan(DNS-1 X),a reverse TGMS(RTGMS)japonica male sterile line,was identified from Diannong S-1.Genetic analysis showed that male sterility was tightly controlled by a single recessive gene,which was supported by the phenotype of the F;and F;populations derived from the cross between DNS-1 X and Yunjing 26(YJ26).Combining simple sequence repeat(SSR)markers and bulked segregation analysis(BSA),we identified a 215 kb region on chromosome 10 as a candidate reverse TGMS region,which was designated as rtmsl-D.It was narrower than the previously reported RTGMS genes rtmsl and tms6(t).The fertility conversion detected in the natural environment showed that DNS-1 X was sterile below 28-30℃;otherwise,it was fertile.Histological analysis further indicated that the pollen abortion was occurred in the young microspore stage.This study will provide new resources for two-line hybrid rice and pave the way for molecular breeding of RTGMS lines.
基金Project supported by the Overseas-Returned Researcher Foundation of China
文摘The Cu-based thermosensitive nanocomposites are made by high energy ball milling. The microstructures and properties of Cu-based thermosensitive nanocomposites are studied by transmission electron microscopy(TEM) and themosensitivity test. The effects of milling time on the microstructures and the thermosensitivity of Cu-based nanocomposite material are researched. The results show that the Cu-based nanocomposite can be made by high energy ball milling. As the milling time increases, the copper particle size decreases in the nanocomposite, then the thermoexpansivity of nanocomposite increases. The nanocomposite is of best thermoexpansivity when the milling time is up to 100 h. At 35- 45 ℃, the nanocomposite shows good thermosensitivity.
文摘A color image formation method is p re sented with thermosensitive liquid crystal polymers. The liquid crystal polymers are capable of reversibly assuming optical states of transparent and scattering lights, and allow picture-element display areas in two colors at least to be co mposed on a surface. The picture elements within color areas are selected if they correspond to the color which is the spectral transmission center. A heat is applied such that the maximum haze degree of the selected picture elements is greater than that of picture elements corresponding to any of the other colo rs.