A microfluidic device to control single crystallization on the micron scale has been developed. The salt solution was stored in the nano-volume gaps between the arrays of protrudent circular plots in the microchip. Th...A microfluidic device to control single crystallization on the micron scale has been developed. The salt solution was stored in the nano-volume gaps between the arrays of protrudent circular plots in the microchip. The mixed organic solvent was injected into the chip as the counter diffusion phase for crystallization forming. This device provides a liquid-liquid interface through which only one phase flows while the other stays at the fixed plot. Therefore, it is possible to control the position of crystallization on the fixed plot. We can control the size and the uniformity of single crystals from 5 to 50 μm in length by adjusting the relative factors, such as interface lifetime, breeds of the mix-organic solvents and injecting velocities. The longer interface lifetime and lower organic solvent injecting velocities can bring up larger and more asymmetric crystals, which nearly shows the same trend compared with the macroscopic crystallization. Finally, the effect of the surfactant on the crystallization in the microdevice was studied. By adding the surfactant into the liquid-liquid interface, smaller sizes of crystals can be obtained without changing the crystal configuration.展开更多
Biopolymer microbeads present substantial benefits for cell expansion,tissue engineering,and drug release applications.However,a fabrication system capable of producing homogeneous microspheres with high precision and...Biopolymer microbeads present substantial benefits for cell expansion,tissue engineering,and drug release applications.However,a fabrication system capable of producing homogeneous microspheres with high precision and controllability for cell proliferation,passaging,harvesting and downstream application is limited.Therefore,we developed a co-flow microfluidics-based system for the generation of uniform and size-controllable gelatin-based microcarriers(GMs)for mesenchymal stromal cells(MSCs)expansion and tissue engineering.Our evaluation of GMs revealed superior homogeneity and efficiency of cellular attachment,expansion and harvest,and MSCs expanded on GMs exhibited high viability while retaining differentiation multipotency.Optimization of passaging and harvesting protocols was achieved through the addition of blank GMs and treatment with collagenase,respectively.Furthermore,we demonstrated that MSC-loaded GMs were printable and could serve as building blocks for tissue regeneration scaffolds.These results suggested that our platform held promise for the fabrication of uniform GMs with downstream application of MSC culture,expansion and tissue engineering.展开更多
Software testability took a lot of interests of software community. Indeed, this concept has been interpreted in a variety of ways. One interpretation is concerned with the extent of the modifications a program compon...Software testability took a lot of interests of software community. Indeed, this concept has been interpreted in a variety of ways. One interpretation is concerned with the extent of the modifications a program component requires, so that the entire behavior of the component is observable and controllable. Another interpretation is the ease with which faults, if present in a program, can be revealed and estimated by the testing process and the propagation, infection and execution (PIE) model. It has been suggested that this particular interpretation of testability might be linked with two concepts: 1) the metric domain-to-range ratio (DRR), i.e. the ratio of the cardinality of the set of all inputs (the domain) to the cardinality of the set of all outputs (the range) and 2) the semantic fault size. First, this paper describes the connections between 1) the domain-to-range ratio and the observability and controllability aspects of testability and 2) the PIE model and fault size. The main goal of the work described here, is to seek greater understanding of testability in general and, ultimately, to find easier ways of determining it. Second, in this paper we try to model the PIE estimation using formalism for process representation system which is MAP formalism. We also use this process model to elaborate and to present the relationship between testability, PIE, DRR and fault size. Our aim is to enhance the guidance mechanisms of the process execution. After clarifying the existing relationship between semantic fault and testability, we improve the MAP model by adding qualitative criteria. We then offer a way to express maps to offer an automatic guidance of the map.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 20775042)the National Basic Research Program of China (Grant No. 2007CB714507)
文摘A microfluidic device to control single crystallization on the micron scale has been developed. The salt solution was stored in the nano-volume gaps between the arrays of protrudent circular plots in the microchip. The mixed organic solvent was injected into the chip as the counter diffusion phase for crystallization forming. This device provides a liquid-liquid interface through which only one phase flows while the other stays at the fixed plot. Therefore, it is possible to control the position of crystallization on the fixed plot. We can control the size and the uniformity of single crystals from 5 to 50 μm in length by adjusting the relative factors, such as interface lifetime, breeds of the mix-organic solvents and injecting velocities. The longer interface lifetime and lower organic solvent injecting velocities can bring up larger and more asymmetric crystals, which nearly shows the same trend compared with the macroscopic crystallization. Finally, the effect of the surfactant on the crystallization in the microdevice was studied. By adding the surfactant into the liquid-liquid interface, smaller sizes of crystals can be obtained without changing the crystal configuration.
基金supported by the National Natural Science Foundation of China(Grant No.52075285)the Applied Basic Research Project of Sichuan Province(Grant No.2021YJ0563).
文摘Biopolymer microbeads present substantial benefits for cell expansion,tissue engineering,and drug release applications.However,a fabrication system capable of producing homogeneous microspheres with high precision and controllability for cell proliferation,passaging,harvesting and downstream application is limited.Therefore,we developed a co-flow microfluidics-based system for the generation of uniform and size-controllable gelatin-based microcarriers(GMs)for mesenchymal stromal cells(MSCs)expansion and tissue engineering.Our evaluation of GMs revealed superior homogeneity and efficiency of cellular attachment,expansion and harvest,and MSCs expanded on GMs exhibited high viability while retaining differentiation multipotency.Optimization of passaging and harvesting protocols was achieved through the addition of blank GMs and treatment with collagenase,respectively.Furthermore,we demonstrated that MSC-loaded GMs were printable and could serve as building blocks for tissue regeneration scaffolds.These results suggested that our platform held promise for the fabrication of uniform GMs with downstream application of MSC culture,expansion and tissue engineering.
文摘Software testability took a lot of interests of software community. Indeed, this concept has been interpreted in a variety of ways. One interpretation is concerned with the extent of the modifications a program component requires, so that the entire behavior of the component is observable and controllable. Another interpretation is the ease with which faults, if present in a program, can be revealed and estimated by the testing process and the propagation, infection and execution (PIE) model. It has been suggested that this particular interpretation of testability might be linked with two concepts: 1) the metric domain-to-range ratio (DRR), i.e. the ratio of the cardinality of the set of all inputs (the domain) to the cardinality of the set of all outputs (the range) and 2) the semantic fault size. First, this paper describes the connections between 1) the domain-to-range ratio and the observability and controllability aspects of testability and 2) the PIE model and fault size. The main goal of the work described here, is to seek greater understanding of testability in general and, ultimately, to find easier ways of determining it. Second, in this paper we try to model the PIE estimation using formalism for process representation system which is MAP formalism. We also use this process model to elaborate and to present the relationship between testability, PIE, DRR and fault size. Our aim is to enhance the guidance mechanisms of the process execution. After clarifying the existing relationship between semantic fault and testability, we improve the MAP model by adding qualitative criteria. We then offer a way to express maps to offer an automatic guidance of the map.
