Magnesium phosphate cements have come under investigation in recent years for use as an alternative to calcium phosphate cements for bone void repair applications.Evidence indicates that magnesium phosphate cements ob...Magnesium phosphate cements have come under investigation in recent years for use as an alternative to calcium phosphate cements for bone void repair applications.Evidence indicates that magnesium phosphate cements obtain higher initial strengths after cement reaction and resorption in more clinically appropriate time frames than commercially available calcium phosphate cements.In this study,amorphous,partially amorphous and crystalline tri-magnesium phosphate powders were synthesized via an aqueous precipitation reaction with subsequent thermal treatment,and characterized using techniques such as X-ray diffraction and Fourier transform infrared spectroscopy.These materials were assessed for their functionality in cementing reaction with a 3.0 mol/L,pH 7.0 ammonium phosphate solution,including setting time and pH evolution in phosphate buffered saline solution.Results indicated that the amorphous and semi-crystalline tri-magnesium phosphate powders were highly reactive with the setting solution but resulted in mechanically weak cements,while the crystalline tri-magnesium phosphate powder reacted efficiently with the cement solution and were mechanically strong following the cement reaction.X-ray diffraction and scanning electron microscopy analyses indicated significant changes in the phase composition and morphology of the cements following incubation in phosphate buffered saline.These were perceived to be detrimental to the integrity of the amorphous and semi-crystalline tri-magnesium phosphate derived cements but not to those created with fully crystalline tri-magnesium phosphate.The crystalline tri-magnesium phosphate material resulted in the most functional cement as this embodiment displayed the most clinically relevant setting time as well as the highest mechanical resilience and neutral pH during incubation in saline solution rendering them potentially viable as bone void fillers.展开更多
During the period of May to October in1999,systematical studies were giv en to the rate of decomposition of Calamagrostis angustifolia litter,the phosphorus content and weight in decomposed residua of litte r,and phos...During the period of May to October in1999,systematical studies were giv en to the rate of decomposition of Calamagrostis angustifolia litter,the phosphorus content and weight in decomposed residua of litte r,and phosphorus content in the corresponding soil in the Sanjiang Plain.At the same time,the simulation models were listed in the paper.The results showed that the rate of we ight lost of decomposition of Calamagrostis angustifolia litter is 29.80%and the maximum of daily rate of weight lost i s 0.25%,which appeared in July.The c hange trend of phosphorus content an d weight in the decomposed residua of l itter is to reduce with the decomposing process,when it comes to the day of157,the decrement amount of the both were respectively 57.69mg /kg and 1.6199mg,which were 72.80%and 76.30%of its previous amount.In addition,th ere is a polynomial minus correlatio nship of phosphorus content between the variation in corresponding soil and the decomp osed residua of litter at the corresp onding period.The study will be help ful to further understand the process and mechanis m of biochemical cycling of nutrient elements in wetland ecosystems,in a ddition,it will also be helpful to the restoration and rebuilding of retrogressive wetlands and reasonable development and utilization of wetlands in the Sanjiang Plain.展开更多
As a kind of cytoskeleton protein,vimentin is a major member of intermediate filament family.Vimentin is found mainly in mesenchymal cells,and its expression and phosphorylation are regulated by many factors.In the pa...As a kind of cytoskeleton protein,vimentin is a major member of intermediate filament family.Vimentin is found mainly in mesenchymal cells,and its expression and phosphorylation are regulated by many factors.In the past,vimentin was revealed as a scaffold maintaining cellular integrity,and recent studies shed lights on the evidence that vimentin played many important roles in cellular adhension,growth,apoptosis,cell signaling as well as inflammatory response.This article summarizes the recent progress of vimentin about its expression and function.Abstract:SUMM ARY As a kind of cytoskeleton protein,vimentin is a majormember of intermed iate filament fam i-ly.V imentin is found mainly in mesenchymal cells,and its expression and phosphorylation are regulated by many factors.In the past,vimentin was revealed as a scaffold maintaining cellular integrity,and re-cent stud ies shed lights on the evidence that vimentin played many important roles in cellular adhension,growth,apoptosis,cell signaling as well as inflammatory response.This article summarizes the recent progress of vimentin about its expression and function.展开更多
基金the financial support of the National Science Foundation(Grant #0933153)Edward R.Weidlein Chair Professorship Funds,University of Pittsburgh,the Center for Complex Engineered Multifunctional Materials(CCEMM), University of PittsburghThe National Science Foundation Graduate Research Fellowship Program(DGE-1247842)
文摘Magnesium phosphate cements have come under investigation in recent years for use as an alternative to calcium phosphate cements for bone void repair applications.Evidence indicates that magnesium phosphate cements obtain higher initial strengths after cement reaction and resorption in more clinically appropriate time frames than commercially available calcium phosphate cements.In this study,amorphous,partially amorphous and crystalline tri-magnesium phosphate powders were synthesized via an aqueous precipitation reaction with subsequent thermal treatment,and characterized using techniques such as X-ray diffraction and Fourier transform infrared spectroscopy.These materials were assessed for their functionality in cementing reaction with a 3.0 mol/L,pH 7.0 ammonium phosphate solution,including setting time and pH evolution in phosphate buffered saline solution.Results indicated that the amorphous and semi-crystalline tri-magnesium phosphate powders were highly reactive with the setting solution but resulted in mechanically weak cements,while the crystalline tri-magnesium phosphate powder reacted efficiently with the cement solution and were mechanically strong following the cement reaction.X-ray diffraction and scanning electron microscopy analyses indicated significant changes in the phase composition and morphology of the cements following incubation in phosphate buffered saline.These were perceived to be detrimental to the integrity of the amorphous and semi-crystalline tri-magnesium phosphate derived cements but not to those created with fully crystalline tri-magnesium phosphate.The crystalline tri-magnesium phosphate material resulted in the most functional cement as this embodiment displayed the most clinically relevant setting time as well as the highest mechanical resilience and neutral pH during incubation in saline solution rendering them potentially viable as bone void fillers.
文摘During the period of May to October in1999,systematical studies were giv en to the rate of decomposition of Calamagrostis angustifolia litter,the phosphorus content and weight in decomposed residua of litte r,and phosphorus content in the corresponding soil in the Sanjiang Plain.At the same time,the simulation models were listed in the paper.The results showed that the rate of we ight lost of decomposition of Calamagrostis angustifolia litter is 29.80%and the maximum of daily rate of weight lost i s 0.25%,which appeared in July.The c hange trend of phosphorus content an d weight in the decomposed residua of l itter is to reduce with the decomposing process,when it comes to the day of157,the decrement amount of the both were respectively 57.69mg /kg and 1.6199mg,which were 72.80%and 76.30%of its previous amount.In addition,th ere is a polynomial minus correlatio nship of phosphorus content between the variation in corresponding soil and the decomp osed residua of litter at the corresp onding period.The study will be help ful to further understand the process and mechanis m of biochemical cycling of nutrient elements in wetland ecosystems,in a ddition,it will also be helpful to the restoration and rebuilding of retrogressive wetlands and reasonable development and utilization of wetlands in the Sanjiang Plain.
文摘As a kind of cytoskeleton protein,vimentin is a major member of intermediate filament family.Vimentin is found mainly in mesenchymal cells,and its expression and phosphorylation are regulated by many factors.In the past,vimentin was revealed as a scaffold maintaining cellular integrity,and recent studies shed lights on the evidence that vimentin played many important roles in cellular adhension,growth,apoptosis,cell signaling as well as inflammatory response.This article summarizes the recent progress of vimentin about its expression and function.Abstract:SUMM ARY As a kind of cytoskeleton protein,vimentin is a majormember of intermed iate filament fam i-ly.V imentin is found mainly in mesenchymal cells,and its expression and phosphorylation are regulated by many factors.In the past,vimentin was revealed as a scaffold maintaining cellular integrity,and re-cent stud ies shed lights on the evidence that vimentin played many important roles in cellular adhension,growth,apoptosis,cell signaling as well as inflammatory response.This article summarizes the recent progress of vimentin about its expression and function.
