Long-terrn injectable microspheres have some inherent disadvantages such as migration of microspheres from the originalsite an.d the burst effect. In order to avoid these problems, microsphere-loaded thermosensitive, ...Long-terrn injectable microspheres have some inherent disadvantages such as migration of microspheres from the originalsite an.d the burst effect. In order to avoid these problems, microsphere-loaded thermosensitive, hydrogel system was designed and expected to achieve a zero-order release Of biomolecular drugs in relativehigh 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 evaporation method, were employee to encapsulate lysozyme and dispersed into thermosensitive pre-gel solution containing methylcellulose （MC）, polyethylene glycol （PEG）, sodium citrate （SC）, and sodium alginate （SA）. The mixture could act asadrug reservoir by.performing sol-gel transition rapidly if the temperature was raised from roomtemperature to 37℃. The in vitro release results showed that the burst effect was avoided due to strengthening ofdiffusion resistance in the gel. The formulation was able.to deliver lysozy.me for over.30 daysin a nearly zero-order release profile with a rate of 32.8μg.d^-1 which exhibits its remarkable potential for effective aoolication in long-term drug delivery.展开更多
On March 16–17, 2008, a sea fog occurred in Dianbai in the west of Guangdong Province and was accompanied by a high-pressure synoptic system. Using comprehensive observation datasets, this study analyzes the evolutio...On March 16–17, 2008, a sea fog occurred in Dianbai in the west of Guangdong Province and was accompanied by a high-pressure synoptic system. Using comprehensive observation datasets, this study analyzes the evolution of liquid water content during this sea fog and investigates the relationships between liquid water content and the average diameters and count densities of fog droplets, air temperature, wind speed and turbulence exchanges. The main results are presented as follows. (1) The sea fog showed a quasi-periodic oscillation characteristic, i.e., it developed, disappeared and then developed again. (2) During the sea fog, the number of fog droplets changed significantly while the changes in average diameter of the fog droplets were relatively small. The development and disappearance of the sea fog correlated significantly with the fog droplet numbers. (3) The air-cooling mechanism played a significant role in sea fog formation and development. However, the influences of this mechanism were not evident during fog persistence. (4) During sea fog formation, weak turbulence exchanges were helpful for fog formation. During sea fog development and persistence, liquid water content increased when turbulence exchanges weakened, and vice versa. The changes in turbulence exchanges were closely related to the quasi-periodic oscillations observed in sea fog presence.展开更多
In this study we characterized and investigated the specific phenomenon of "companion drops" in the drop-ondemand(DOD) ink jetting process.A series of simulations based on a piezoelectric DOD printhead syste...In this study we characterized and investigated the specific phenomenon of "companion drops" in the drop-ondemand(DOD) ink jetting process.A series of simulations based on a piezoelectric DOD printhead system is presented,adapting the volume-of-fluid(VOF) interface-capturing method to track the boundary evolution and model the interfacial physics.The results illustrate the causality between the generation of companion drops and droplet deviation behavior,as well as their close correlations with ink jetting straightness and printing accuracy.The characteristics of companion drops are summarized and compared with those of satellite drops.Also,a theoretical mechanism for the generation of companion drops is presented,and their effects and behaviors are analyzed and discussed.Finally,the effects of critical factors on the generation of companion drops are investigated and characterized based on variations in the printable pressure range.Recommendations are given for the suppression of companion drops and for the improvement of printing accuracy.展开更多
基金Supported by the National Natural Science Foundation of China （No.20576057） and Fundamental Research Foundation of Tsinghua University （JCqn2005033）.
文摘Long-terrn injectable microspheres have some inherent disadvantages such as migration of microspheres from the originalsite an.d the burst effect. In order to avoid these problems, microsphere-loaded thermosensitive, hydrogel system was designed and expected to achieve a zero-order release Of biomolecular drugs in relativehigh 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 evaporation method, were employee to encapsulate lysozyme and dispersed into thermosensitive pre-gel solution containing methylcellulose （MC）, polyethylene glycol （PEG）, sodium citrate （SC）, and sodium alginate （SA）. The mixture could act asadrug reservoir by.performing sol-gel transition rapidly if the temperature was raised from roomtemperature to 37℃. The in vitro release results showed that the burst effect was avoided due to strengthening ofdiffusion resistance in the gel. The formulation was able.to deliver lysozy.me for over.30 daysin a nearly zero-order release profile with a rate of 32.8μg.d^-1 which exhibits its remarkable potential for effective aoolication in long-term drug delivery.
基金Natural Science Foundation of China (40675013)Foundation project of Nanjing University of Information Science & TechnologyProject on natural science for universities and colleges in Jiangsu province
文摘On March 16–17, 2008, a sea fog occurred in Dianbai in the west of Guangdong Province and was accompanied by a high-pressure synoptic system. Using comprehensive observation datasets, this study analyzes the evolution of liquid water content during this sea fog and investigates the relationships between liquid water content and the average diameters and count densities of fog droplets, air temperature, wind speed and turbulence exchanges. The main results are presented as follows. (1) The sea fog showed a quasi-periodic oscillation characteristic, i.e., it developed, disappeared and then developed again. (2) During the sea fog, the number of fog droplets changed significantly while the changes in average diameter of the fog droplets were relatively small. The development and disappearance of the sea fog correlated significantly with the fog droplet numbers. (3) The air-cooling mechanism played a significant role in sea fog formation and development. However, the influences of this mechanism were not evident during fog persistence. (4) During sea fog formation, weak turbulence exchanges were helpful for fog formation. During sea fog development and persistence, liquid water content increased when turbulence exchanges weakened, and vice versa. The changes in turbulence exchanges were closely related to the quasi-periodic oscillations observed in sea fog presence.
基金Project supported by the National Key Technology R&D Program(No. 2011BAD01B03)the Key Project of Science and Technology Program of Zhejiang Province (No. 2009C11099)the Zhejiang Provincial Natural Science Foundation (No. Y1110230)
文摘In this study we characterized and investigated the specific phenomenon of "companion drops" in the drop-ondemand(DOD) ink jetting process.A series of simulations based on a piezoelectric DOD printhead system is presented,adapting the volume-of-fluid(VOF) interface-capturing method to track the boundary evolution and model the interfacial physics.The results illustrate the causality between the generation of companion drops and droplet deviation behavior,as well as their close correlations with ink jetting straightness and printing accuracy.The characteristics of companion drops are summarized and compared with those of satellite drops.Also,a theoretical mechanism for the generation of companion drops is presented,and their effects and behaviors are analyzed and discussed.Finally,the effects of critical factors on the generation of companion drops are investigated and characterized based on variations in the printable pressure range.Recommendations are given for the suppression of companion drops and for the improvement of printing accuracy.
