Urban spatial expansion characteristics are the responses of urbanization acts on the geographical space. Analyzing the characteristics can reveal the process of urban expansion and mechanism which is one of useful me...Urban spatial expansion characteristics are the responses of urbanization acts on the geographical space. Analyzing the characteristics can reveal the process of urban expansion and mechanism which is one of useful methods to find out the sustainable land use strategy balancing development and protection. In this paper, two main methods have been deployed in analyzing the spatial expansion characteristics of rapid urbanization region. One is the expansion index method and the other is fractal dimension method. And the results show that town-level urban sprawl has increased in a non-linear way since 1985, and even the increments of the urban expansion intensity are fluctuated. Morphology transformation from scatter to concentration is common phenomenon in the process of urbanization in the towns. From the morphology point of view, downtowns are more homogenous than towns with less variation. The concentration is the leading development trend in downtowns. And the more distance from the downtown is, the more spatial pattern morphology will be observed. These characteristics indicate that macro-scale policies of economic development and land use management have great impacts on the formation and characteristics of spatial patterns of urban dynamic patterns.展开更多
BACKGROUND Palatal expansion treatment has been used to expand the constricted maxillary arch and has become a routine procedure in orthodontic practice over the past decades.However,the long-term stability of expansi...BACKGROUND Palatal expansion treatment has been used to expand the constricted maxillary arch and has become a routine procedure in orthodontic practice over the past decades.However,the long-term stability of expansion in the permanent dentition without a surgical approach is uncertain.CASE SUMMARY We present the case of a 15-year-old boy with Class II malocclusion and constricted arches.The patient was treated with rapid palatal expansion(RPE)followed by a fixed orthodontic appliance.A 7-year follow-up evaluation was performed by analyzing cephalometric radiographs,plaster models,and photographs.The patient’s constricted maxillary and mandibular arches were relived after the expansion treatment.A Class I occlusion and normal arch form were established and maintained in the long-term.CONCLUSION RPE treatment is successful in solving constricted dental arch in the permanent dentition without a surgical approach.Permanent retention and even occlusal contact help prevent long-term relapse.展开更多
To improve the encapsulation efficiency and minimize particle agglomeration of liposomes,rapid expansion from supercritical to surfactant solution(RESSS) was applied to self-assembly of liposomes entrapping hinesol in...To improve the encapsulation efficiency and minimize particle agglomeration of liposomes,rapid expansion from supercritical to surfactant solution(RESSS) was applied to self-assembly of liposomes entrapping hinesol in supercritical carbon dioxide(SC-CO_2) medium.In the process,the solution of liposomal materials and hinesol dissolved in the mixture of SC-CO_2/ethanol was sprayed into a surfactant solution.The surfactant provided stabilization for liposomes by preventing bubbles overflowing and liposomes agglomeration during the spraying process.The encapsulating performance and particle size distribution of liposomes could be controlled by changing expansion processing conditions.When the solution was sprayed into a 5.0%Poloxamer 188 solution at a flow rate of 2 L/min, the entrapment efficiency and average particle size of liposomes were found to be 88.26%and 124 nm,respectively, which came to the standards of Chinese pharmacopoeia.The results show RESSS process provides an innovative method for formation of liposomes incorporating valid compositions extracted from the Chinese traditional medicines in SC-CO_2 medium.展开更多
Poly(1,1,2,2- tetrahydroperfluorodecyl acrylate) (poly (TA-N)) was synthesized in laboratory. The resulting morphology of rapid expansion of supercritical solution (RESS) sprays of poly(TA - N) was investigated. At ap...Poly(1,1,2,2- tetrahydroperfluorodecyl acrylate) (poly (TA-N)) was synthesized in laboratory. The resulting morphology of rapid expansion of supercritical solution (RESS) sprays of poly(TA - N) was investigated. At apre - expansion temperature of 45℃), amorphous polymer was formed. At temperature around 60 ℃ to 80 ℃ , fibers were formed. Increase of temperature increasesparticle size slightly. At temperature of 105℃ , most of particles are spheres. The RESS is an attractive process. To apply the polymers desired for coating applications in an organic solvent - free process that is economically viable , and it will have implications for pollution prevention during polymer film展开更多
This paper is concerned with the distributional properties of a median unbiased estimator of ARCH(0,1)coefficient.The exact distribution of the estimator can be easily derived,however its practical calculations are to...This paper is concerned with the distributional properties of a median unbiased estimator of ARCH(0,1)coefficient.The exact distribution of the estimator can be easily derived,however its practical calculations are too heavy to implement, even though the middle range of sample sizes.Since the estimator is shown to have asymptotic normality,asymptotic expansions for the distribution and the percentiles of the estimator are derived as the refinements.Accuracies of expansion formulas are evaluated numerically,and the results of which show that we can effectively use the expansion as a fine approximation of the distribution with rapid calculations.Derived expansion are applied to testing hypothesis of stationarity,and an implementation for a real data set is illustrated.展开更多
目的:探讨ARCH钛板联合单开门椎管扩大成形术(expansive single open door-laminoplasty,EOLP)治疗脊髓型颈椎病(cervical spondylotic myelopathy,CSM)的近期临床疗效。方法:2016年1月至2016年12月将ARCH钛板做内固定材料的EOLP应用于3...目的:探讨ARCH钛板联合单开门椎管扩大成形术(expansive single open door-laminoplasty,EOLP)治疗脊髓型颈椎病(cervical spondylotic myelopathy,CSM)的近期临床疗效。方法:2016年1月至2016年12月将ARCH钛板做内固定材料的EOLP应用于32例CSM患者的治疗中,男23例,女9例;年龄39～82岁,平均64.5岁;病程6～24个月,平均13.1个月。临床疗效评定采用日本骨科协会(JOA)评分法,评分内容包括上下肢运动功能、肢体感觉功能、膀胱功能。通过影像学资料测量术前和术后6个月最狭窄节段的椎管矢状径,计算其改善率以明确减压效果。结果:所有患者获得随访,时间6～20个月,平均12.2个月。32例患者的术前症状均有不同程度好转,JOA评分由术前的9.78±1.34提高至术后6个月的12.94±1.16,JOA改善率为(44.09±11.06)%(P<0.01)。椎管扩大明显,最狭窄处椎管矢状径由术前的(8.47±0.60)mm扩大至术后6个月的(12.51±0.78)mm,改善率为(48.27±11.81)%(P<0.01)。随访期间未见内固定物松动、移位、断裂及"再关门"现象。结论:ARCH钛板联合EOLP治疗CSM可明显减少出现"再关门"及其他相关术后并发症的可能,近期临床疗效满意。展开更多
文摘Urban spatial expansion characteristics are the responses of urbanization acts on the geographical space. Analyzing the characteristics can reveal the process of urban expansion and mechanism which is one of useful methods to find out the sustainable land use strategy balancing development and protection. In this paper, two main methods have been deployed in analyzing the spatial expansion characteristics of rapid urbanization region. One is the expansion index method and the other is fractal dimension method. And the results show that town-level urban sprawl has increased in a non-linear way since 1985, and even the increments of the urban expansion intensity are fluctuated. Morphology transformation from scatter to concentration is common phenomenon in the process of urbanization in the towns. From the morphology point of view, downtowns are more homogenous than towns with less variation. The concentration is the leading development trend in downtowns. And the more distance from the downtown is, the more spatial pattern morphology will be observed. These characteristics indicate that macro-scale policies of economic development and land use management have great impacts on the formation and characteristics of spatial patterns of urban dynamic patterns.
基金Supported by the National Natural Science Foundation of China No.81970909(to Liu DW),No.51903003(to Yu TT)the New Clinical Technology Fund of PKUSS,No.PKUSSNCT-11A07(to Liu DW)Peking University Medicine Seed Fund for Interdisciplinary Research,No.BMU2018MX007(to Liu DW).
文摘BACKGROUND Palatal expansion treatment has been used to expand the constricted maxillary arch and has become a routine procedure in orthodontic practice over the past decades.However,the long-term stability of expansion in the permanent dentition without a surgical approach is uncertain.CASE SUMMARY We present the case of a 15-year-old boy with Class II malocclusion and constricted arches.The patient was treated with rapid palatal expansion(RPE)followed by a fixed orthodontic appliance.A 7-year follow-up evaluation was performed by analyzing cephalometric radiographs,plaster models,and photographs.The patient’s constricted maxillary and mandibular arches were relived after the expansion treatment.A Class I occlusion and normal arch form were established and maintained in the long-term.CONCLUSION RPE treatment is successful in solving constricted dental arch in the permanent dentition without a surgical approach.Permanent retention and even occlusal contact help prevent long-term relapse.
基金Supported by the National Natural Science Foundation of China(No.20606013)the Produce-learn-research Project of Shenzhen Scinence and Technology Program(No.2008342)the Fundamental Research Project of Shenzhen Science and Technology, China(No.JC200903120089A)
文摘To improve the encapsulation efficiency and minimize particle agglomeration of liposomes,rapid expansion from supercritical to surfactant solution(RESSS) was applied to self-assembly of liposomes entrapping hinesol in supercritical carbon dioxide(SC-CO_2) medium.In the process,the solution of liposomal materials and hinesol dissolved in the mixture of SC-CO_2/ethanol was sprayed into a surfactant solution.The surfactant provided stabilization for liposomes by preventing bubbles overflowing and liposomes agglomeration during the spraying process.The encapsulating performance and particle size distribution of liposomes could be controlled by changing expansion processing conditions.When the solution was sprayed into a 5.0%Poloxamer 188 solution at a flow rate of 2 L/min, the entrapment efficiency and average particle size of liposomes were found to be 88.26%and 124 nm,respectively, which came to the standards of Chinese pharmacopoeia.The results show RESSS process provides an innovative method for formation of liposomes incorporating valid compositions extracted from the Chinese traditional medicines in SC-CO_2 medium.
文摘Poly(1,1,2,2- tetrahydroperfluorodecyl acrylate) (poly (TA-N)) was synthesized in laboratory. The resulting morphology of rapid expansion of supercritical solution (RESS) sprays of poly(TA - N) was investigated. At apre - expansion temperature of 45℃), amorphous polymer was formed. At temperature around 60 ℃ to 80 ℃ , fibers were formed. Increase of temperature increasesparticle size slightly. At temperature of 105℃ , most of particles are spheres. The RESS is an attractive process. To apply the polymers desired for coating applications in an organic solvent - free process that is economically viable , and it will have implications for pollution prevention during polymer film
文摘This paper is concerned with the distributional properties of a median unbiased estimator of ARCH(0,1)coefficient.The exact distribution of the estimator can be easily derived,however its practical calculations are too heavy to implement, even though the middle range of sample sizes.Since the estimator is shown to have asymptotic normality,asymptotic expansions for the distribution and the percentiles of the estimator are derived as the refinements.Accuracies of expansion formulas are evaluated numerically,and the results of which show that we can effectively use the expansion as a fine approximation of the distribution with rapid calculations.Derived expansion are applied to testing hypothesis of stationarity,and an implementation for a real data set is illustrated.
文摘目的:探讨ARCH钛板联合单开门椎管扩大成形术(expansive single open door-laminoplasty,EOLP)治疗脊髓型颈椎病(cervical spondylotic myelopathy,CSM)的近期临床疗效。方法:2016年1月至2016年12月将ARCH钛板做内固定材料的EOLP应用于32例CSM患者的治疗中,男23例,女9例;年龄39～82岁,平均64.5岁;病程6～24个月,平均13.1个月。临床疗效评定采用日本骨科协会(JOA)评分法,评分内容包括上下肢运动功能、肢体感觉功能、膀胱功能。通过影像学资料测量术前和术后6个月最狭窄节段的椎管矢状径,计算其改善率以明确减压效果。结果:所有患者获得随访,时间6～20个月,平均12.2个月。32例患者的术前症状均有不同程度好转,JOA评分由术前的9.78±1.34提高至术后6个月的12.94±1.16,JOA改善率为(44.09±11.06)%(P<0.01)。椎管扩大明显,最狭窄处椎管矢状径由术前的(8.47±0.60)mm扩大至术后6个月的(12.51±0.78)mm,改善率为(48.27±11.81)%(P<0.01)。随访期间未见内固定物松动、移位、断裂及"再关门"现象。结论:ARCH钛板联合EOLP治疗CSM可明显减少出现"再关门"及其他相关术后并发症的可能,近期临床疗效满意。
