Myopia is the leading cause of visual impairments worldwide. Some studies revealed that visual experience in early life affected the final myopia, indicating that environmental factors play an impellent role in the de...Myopia is the leading cause of visual impairments worldwide. Some studies revealed that visual experience in early life affected the final myopia, indicating that environmental factors play an impellent role in the development of myopia. However, risk factors of myopia are still not identified among adolescents in China. A total of 4104 cases of myopia symptom and 3306 emmetropia controls were selected from students in primary and middle schools in Wuhan in 2008. We identified the risk factors associated with myopia symptom by multivariate logistic regression in this cross-sectional study and constructed a risk score system for myopia symptom. The value of the area under the receiver operating characteristic curve (ROC) was 0.735. Furthermore, we followed up 93 students aged 7-9 years for one year and calculated the total points using the score system. We found no significant difference between the final myopia symptom and the results predicted by the total points by pair chi-square test (P>0.05). The score system had a modest ability to estimate the risk factors of myopia symptom. Using this score system, we could identify the students who are at risk of myopia symptom in the future according to their behaviors and environmental factors, and take measures to slow the progress of myopia symptom.展开更多
Use of the scanning electron microscope (SEM) to characterize ores provides mineralogists and metallurgists with invaluable information for the optimisation of processes. Manually obtaining relevant information such a...Use of the scanning electron microscope (SEM) to characterize ores provides mineralogists and metallurgists with invaluable information for the optimisation of processes. Manually obtaining relevant information such as, for example, mineral coatings that may interfere with flotation, mineral separations, the location of values, mineralogical or process reasons for low recovery, etc, can be exhausting and time consuming. For this reason, automated SEM methods for mineralogical characterisation have been devised. These methods rely on qualitative analyses of the samples using EDX or BSD grey levels to classify the phases present. The non-quantitative nature of the analyses means that other techniques, such as electron microprobe analysis (EMPA), must be used in conjunction with the SEM to obtain quantitative information of the sample. To overcome this limitation, Carl Zeiss has devised a method for the quantitative analysis of the mineralogy of any ore or ore-derived processed material; allowing for the full quantitative evaluation of a resource to be performed automatically by the SEM.展开更多
In recent years,bamboo has been widely used in a broad range of applications,a thorough understanding of the structural characteristics of bamboo nodes is essential for better processing and manufacturing of biomimeti...In recent years,bamboo has been widely used in a broad range of applications,a thorough understanding of the structural characteristics of bamboo nodes is essential for better processing and manufacturing of biomimetic materials.This study investigated the complex anatomical structure for the nodes of two bamboo species,Indocalamus latifolius(Keng)McClure and Shibataea chinensis Nakai,using a high-resolution X-ray microtomography(μCT).The results show that the vascular bundle system in the nodal region of I.latifolius and S.chinensis is a net-like structure composed of horizontal and axial vascular bundles.Furthermore,the fiber sheath surrounding metaxylem vessels tended to be shorter in the tangential direction.This structure of bamboo nodes facilitates the tangential and axial transport of moisture and nutrients.The anatomical structure of I.latifolius and S.chinensis nodes has obvious differences,especially in the arrangement of vascular bundles.Vascular bundle frequency was significantly higher in S.chinensis nodes than in I.latifolius nodes.These findings indicate thatμCT is a nondestructive three-dimensional imaging method that can used to examine the anatomical structure of bamboo nodes.展开更多
文摘Myopia is the leading cause of visual impairments worldwide. Some studies revealed that visual experience in early life affected the final myopia, indicating that environmental factors play an impellent role in the development of myopia. However, risk factors of myopia are still not identified among adolescents in China. A total of 4104 cases of myopia symptom and 3306 emmetropia controls were selected from students in primary and middle schools in Wuhan in 2008. We identified the risk factors associated with myopia symptom by multivariate logistic regression in this cross-sectional study and constructed a risk score system for myopia symptom. The value of the area under the receiver operating characteristic curve (ROC) was 0.735. Furthermore, we followed up 93 students aged 7-9 years for one year and calculated the total points using the score system. We found no significant difference between the final myopia symptom and the results predicted by the total points by pair chi-square test (P>0.05). The score system had a modest ability to estimate the risk factors of myopia symptom. Using this score system, we could identify the students who are at risk of myopia symptom in the future according to their behaviors and environmental factors, and take measures to slow the progress of myopia symptom.
文摘Use of the scanning electron microscope (SEM) to characterize ores provides mineralogists and metallurgists with invaluable information for the optimisation of processes. Manually obtaining relevant information such as, for example, mineral coatings that may interfere with flotation, mineral separations, the location of values, mineralogical or process reasons for low recovery, etc, can be exhausting and time consuming. For this reason, automated SEM methods for mineralogical characterisation have been devised. These methods rely on qualitative analyses of the samples using EDX or BSD grey levels to classify the phases present. The non-quantitative nature of the analyses means that other techniques, such as electron microprobe analysis (EMPA), must be used in conjunction with the SEM to obtain quantitative information of the sample. To overcome this limitation, Carl Zeiss has devised a method for the quantitative analysis of the mineralogy of any ore or ore-derived processed material; allowing for the full quantitative evaluation of a resource to be performed automatically by the SEM.
基金This research was funded by the Nature Science Foundation of China(Grant No.31670565)the National Key Research&Development Program(No.2016YFD0600904).
文摘In recent years,bamboo has been widely used in a broad range of applications,a thorough understanding of the structural characteristics of bamboo nodes is essential for better processing and manufacturing of biomimetic materials.This study investigated the complex anatomical structure for the nodes of two bamboo species,Indocalamus latifolius(Keng)McClure and Shibataea chinensis Nakai,using a high-resolution X-ray microtomography(μCT).The results show that the vascular bundle system in the nodal region of I.latifolius and S.chinensis is a net-like structure composed of horizontal and axial vascular bundles.Furthermore,the fiber sheath surrounding metaxylem vessels tended to be shorter in the tangential direction.This structure of bamboo nodes facilitates the tangential and axial transport of moisture and nutrients.The anatomical structure of I.latifolius and S.chinensis nodes has obvious differences,especially in the arrangement of vascular bundles.Vascular bundle frequency was significantly higher in S.chinensis nodes than in I.latifolius nodes.These findings indicate thatμCT is a nondestructive three-dimensional imaging method that can used to examine the anatomical structure of bamboo nodes.
