The effects of the morphologies of liquid crystal (LC) droplets left in polymer network on the performance of polymer dispersed liquid crystal composite films were investigated.By adjusting the relative content range ...The effects of the morphologies of liquid crystal (LC) droplets left in polymer network on the performance of polymer dispersed liquid crystal composite films were investigated.By adjusting the relative content range of the crosslinking and diluents,the morphologies of polymer network can be changed.Therefore,the properties of PDLC composite films with imparity polymer morphologies were obtained by experiments and the finite element simulation.Results of the experimental and finite element simulation showed that the electro-optical properties of PDLC composite films were inversely proportional to the domain size of the polymer network and the mechanical properties were proportional to the domain size of the polymer network.展开更多
Three-dimensional(3D) histology utilizes tissue clearing techniques to turn intact tissues transparent,allowing rapid interrogation of tissue architecture in three dimensions.In this article,we summarized the availa...Three-dimensional(3D) histology utilizes tissue clearing techniques to turn intact tissues transparent,allowing rapid interrogation of tissue architecture in three dimensions.In this article,we summarized the available tissue clearing methods and classified them according to their physicochemical principles of operation,which provided a framework for one to choose the best techniques for various research settings.Recent attempts in addressing various questions regarding the degenerating and regenerating nervous system have been promising with the use of 3D histological techniques.展开更多
Background:Neuroimaging-based connectome studies have indicated that major depressive disorder(MDD)is associated with dis-rupted topological organization of large-scale brain networks.However,the disruptions and their...Background:Neuroimaging-based connectome studies have indicated that major depressive disorder(MDD)is associated with dis-rupted topological organization of large-scale brain networks.However,the disruptions and their clinical and cognitive relevance are not well established for morphological brain networks in adolescent MDD.Objective:To investigate the topological alterations of single-subject morphological brain networks in adolescent MDD.Methods:Twenty-five first-episode,treatment-naive adolescents with MDD and 19 healthy controls(HCs)underwent T1-weighted magnetic resonance imaging and a battery of neuropsychological tests.Single-subject morphological brain networks were constructed separately based on cortical thickness,fractal dimension,gyrification index,and sulcus depth,and topologically characterized by graph-based approaches.Between-group differences were inferred by permutation testing.For significant alterations,partial correla-tions were used to examine their associations with clinical and neuropsychological variables in the patients.Finally,a support vector machine was used to classify the patients from controls.Results:Compared with the HCs,the patients exhibited topological alterations only in cortical thickness-based networks character-ized by higher nodal centralities in parietal(left primary sensory cortex)but lower nodal centralities in temporal(left parabelt complex,right perirhinal ectorhinal cortex,right area PHT and right ventral visual complex)regions.Moreover,decreased nodal centralities of some temporal regions were correlated with cognitive dysfunction and clinical characteristics of the patients.These results were largely reproducible for binary and weighted network analyses.Finally,topological properties of the cortical thickness-based net-works were able to distinguish the MDD adolescents from HCs with 87.6%accuracy.Conclusion:Adolescent MDD is associated with disrupted topological organization of morphological brain networks,and the disrup-tions provide potential biomarkers for diagnosing and monitoring the disease.展开更多
Structures having nanoscale 3 D geometries are valuable as multifunctional materials, where multi-continuous microphases can synergistically influence mechanical, optical, transport and other properties. Such very hig...Structures having nanoscale 3 D geometries are valuable as multifunctional materials, where multi-continuous microphases can synergistically influence mechanical, optical, transport and other properties. Such very high interface surface to volume ratio structures occur in a variety of materials including natural materials such as butter fly wings and sea urchin exoskeletons and in synthetic self-assembled structures such as surfactant/water systems and block polymers. Quantitative morphological characterization of such complex geometric structures is quite challenging. Unit cell sizes range from 10–300 nm with corresponding feature sizes on the 2–50 nm scale. Since these nanoscale network structures are bicontinuous, when one constituent is removed, the structure is still self supporting. Removal of one component produces a nanoporous material that may be in-filled with another component, or the surfaces of the nanopores can be coated with ultra-thin layers by atomic layer deposition to offer multifunctional capabilities. Due to the ability to individually tailor the properties of the network(s) and matrix,for example, to create strong dielectric or impedance contrast, such spatially periodic structures are excellent for the interference of waves(electromagnetic for photonic applications and acoustic for phononic applications) that can lead to bandgaps and hence the control of wave propagation in the material. This mini-review will focus on networks formed by bottom up self assembly of block polymers. In addition to structural issues, we emphasize the special physical properties related to bi-or tri-continuous networks.展开更多
The polymer stabilized liquid crystal(PSLC)film is a relatively novel electro-optical material,which is generally obtained by dissolving a small amount of a bifunctional photoreactive monomer in a low molecular mass l...The polymer stabilized liquid crystal(PSLC)film is a relatively novel electro-optical material,which is generally obtained by dissolving a small amount of a bifunctional photoreactive monomer in a low molecular mass liquid crystal.In this paper,the PSLC films were prepared with photoreactive biphenyl methacrylate monomers by photopolymerization induced phase separation.The effects of liquid crystal concentration,curing time,monomer structures and alignment layer on the electro-optical properties of PSLC films were investigated.The results show that the transmittance in the OFF state(TOFF)increased with the liquid crystal concentration,but the driving voltage decreased.TOFF was also influenced by the curing time.Furthermore,when polyimide was used as alignment layer,the films prepared from the bifunctional monomer shows a higher TOFF,while those from the single functional monomer exhibited a deformed electro-optical curve due to the unsteady polymer networks.展开更多
文摘The effects of the morphologies of liquid crystal (LC) droplets left in polymer network on the performance of polymer dispersed liquid crystal composite films were investigated.By adjusting the relative content range of the crosslinking and diluents,the morphologies of polymer network can be changed.Therefore,the properties of PDLC composite films with imparity polymer morphologies were obtained by experiments and the finite element simulation.Results of the experimental and finite element simulation showed that the electro-optical properties of PDLC composite films were inversely proportional to the domain size of the polymer network and the mechanical properties were proportional to the domain size of the polymer network.
文摘Three-dimensional(3D) histology utilizes tissue clearing techniques to turn intact tissues transparent,allowing rapid interrogation of tissue architecture in three dimensions.In this article,we summarized the available tissue clearing methods and classified them according to their physicochemical principles of operation,which provided a framework for one to choose the best techniques for various research settings.Recent attempts in addressing various questions regarding the degenerating and regenerating nervous system have been promising with the use of 3D histological techniques.
基金supported by the Key-Area Research and Development Program of Guangdong Province (No.2019B030335001)National Natural Science Foundation of China (Nos.81922036)+1 种基金Key Realm R&D Program of Guangzhou (No.202007030005)Natural Science Foundation of Guangdong Province (2021A1515010746).
文摘Background:Neuroimaging-based connectome studies have indicated that major depressive disorder(MDD)is associated with dis-rupted topological organization of large-scale brain networks.However,the disruptions and their clinical and cognitive relevance are not well established for morphological brain networks in adolescent MDD.Objective:To investigate the topological alterations of single-subject morphological brain networks in adolescent MDD.Methods:Twenty-five first-episode,treatment-naive adolescents with MDD and 19 healthy controls(HCs)underwent T1-weighted magnetic resonance imaging and a battery of neuropsychological tests.Single-subject morphological brain networks were constructed separately based on cortical thickness,fractal dimension,gyrification index,and sulcus depth,and topologically characterized by graph-based approaches.Between-group differences were inferred by permutation testing.For significant alterations,partial correla-tions were used to examine their associations with clinical and neuropsychological variables in the patients.Finally,a support vector machine was used to classify the patients from controls.Results:Compared with the HCs,the patients exhibited topological alterations only in cortical thickness-based networks character-ized by higher nodal centralities in parietal(left primary sensory cortex)but lower nodal centralities in temporal(left parabelt complex,right perirhinal ectorhinal cortex,right area PHT and right ventral visual complex)regions.Moreover,decreased nodal centralities of some temporal regions were correlated with cognitive dysfunction and clinical characteristics of the patients.These results were largely reproducible for binary and weighted network analyses.Finally,topological properties of the cortical thickness-based net-works were able to distinguish the MDD adolescents from HCs with 87.6%accuracy.Conclusion:Adolescent MDD is associated with disrupted topological organization of morphological brain networks,and the disrup-tions provide potential biomarkers for diagnosing and monitoring the disease.
基金supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences (de-sc0014457)
文摘Structures having nanoscale 3 D geometries are valuable as multifunctional materials, where multi-continuous microphases can synergistically influence mechanical, optical, transport and other properties. Such very high interface surface to volume ratio structures occur in a variety of materials including natural materials such as butter fly wings and sea urchin exoskeletons and in synthetic self-assembled structures such as surfactant/water systems and block polymers. Quantitative morphological characterization of such complex geometric structures is quite challenging. Unit cell sizes range from 10–300 nm with corresponding feature sizes on the 2–50 nm scale. Since these nanoscale network structures are bicontinuous, when one constituent is removed, the structure is still self supporting. Removal of one component produces a nanoporous material that may be in-filled with another component, or the surfaces of the nanopores can be coated with ultra-thin layers by atomic layer deposition to offer multifunctional capabilities. Due to the ability to individually tailor the properties of the network(s) and matrix,for example, to create strong dielectric or impedance contrast, such spatially periodic structures are excellent for the interference of waves(electromagnetic for photonic applications and acoustic for phononic applications) that can lead to bandgaps and hence the control of wave propagation in the material. This mini-review will focus on networks formed by bottom up self assembly of block polymers. In addition to structural issues, we emphasize the special physical properties related to bi-or tri-continuous networks.
基金supported by the National Key R&D Program of China(2019YFA0706802)Shenzhen Science and Technology Program(CJGJZD20210408092602006)the Science and Technology Major Project of Henan Province(221100240400)。
基金supported by the National Natural Science Foundation of China(Grant No.50773045)Talent introduction start-up Found of Sichuan University(No.0082204127074).
文摘The polymer stabilized liquid crystal(PSLC)film is a relatively novel electro-optical material,which is generally obtained by dissolving a small amount of a bifunctional photoreactive monomer in a low molecular mass liquid crystal.In this paper,the PSLC films were prepared with photoreactive biphenyl methacrylate monomers by photopolymerization induced phase separation.The effects of liquid crystal concentration,curing time,monomer structures and alignment layer on the electro-optical properties of PSLC films were investigated.The results show that the transmittance in the OFF state(TOFF)increased with the liquid crystal concentration,but the driving voltage decreased.TOFF was also influenced by the curing time.Furthermore,when polyimide was used as alignment layer,the films prepared from the bifunctional monomer shows a higher TOFF,while those from the single functional monomer exhibited a deformed electro-optical curve due to the unsteady polymer networks.