We propose a method to determine the thickness of non-edge-on disk galaxies from their observed structure of spiral arms, based on the solution of the truly three-dimensional Poisson's equation for a logarithmic d...We propose a method to determine the thickness of non-edge-on disk galaxies from their observed structure of spiral arms, based on the solution of the truly three-dimensional Poisson's equation for a logarithmic disturbance of density and under the condition where the self-consistency of the density wave theory is no longer valid. From their measured number of arms, pitch angle and location of the innermost point of the spiral arms, we derive and present the thicknesses of 34 spiral galaxies.展开更多
OBJECTIVE To observe the pattern of changes in the proliferation and apoptosis at different stages of large bowel carcinoma in mice, and to explore the effects of the imbalance of apoptosis and proliferation at differ...OBJECTIVE To observe the pattern of changes in the proliferation and apoptosis at different stages of large bowel carcinoma in mice, and to explore the effects of the imbalance of apoptosis and proliferation at different stages of large-intestine carcinogenesis.METHODS An experimental animal model for large intestine carcinogenesis of KUNMING-strain mice was used. The carcinomas were induced by subcuteneous injection of dimethylhydrazine (DMH) and the distribution and density changes of proliferating and apoptotic cells observed through multistages toward cancer formation. The animals were killed in groups at the 12th, 18th, 24th,and 32nd weeks of carcinoma induction. The apoptotic and proliferating cells were labeled separately using TUNEL and PCNA immunohistochemical staining methodsRF, RESULTS In the normal mouse mucosa, all the apoptotic cells were situated in the superficial layers, however, the proliferating cells were situated in the basement layers, and the amount of both were small. In the early stage of carcinoma induction, the proliferation and the apoptotic cells slightly increased in amount, but there were no obvious changes in their ratio. In the medium stage, the densities of both distinctly increased, but there were no obvious changes in the ratio. In the late stage, the densities of the proliferating and the apoptotic cells in the non-carcinoma mucosa were higher than those at other stages. The proliferating cells in the dysplastic mucosa increased progressively with the increasing degree of the lesions. Although the apoptotic cells increased, their changes did not occur with the degree of the lesions. Their ratio showed a decreasing tendency with the degree of the lesions.CONCLUSIONS (①The presence of an imbalance between cell proliferation and apoptosis was confirmed in the course of large intestine carcinogenesis in a mouse model. ②In the early stage of carcinoma induction both proliferation and apoptosis were at a low level; in the medium stage, they were both at a high level; and in the late stage (that is in carcinoma), proliferation was at a very high level, while apoptosis was at a low level. ③The proliferating cells increased progressively with the degree of dysplasia. There were no obvious changes in the apoptotic cells and their ratio to the proliferating cell sshowed a progressively increasing tendency. ④In the stage of cancer formation, the most essential change was the excessive decrease in the ratio of apoptosis to proliferation. These results support the hypothesis of "Cell Selective Proliferation", which was raised by authors previously in a study on human large bowel carcinoma.展开更多
Background:Brain structural alterations of the striatum have been frequently observed in internet gaming disorder(IGD);however,the replicability of the results and the associations with social-affective dysregulations...Background:Brain structural alterations of the striatum have been frequently observed in internet gaming disorder(IGD);however,the replicability of the results and the associations with social-affective dysregulations such as social anxiety remain to be determined.Methods:The present study combined a dimensional neuroimaging approach with both voxel-wise and data-driven multivariate approaches to(i)replicate our previous results on a negative association between IGD symptom load(assessed by the Internet Gaming Disorder Scale-Short Form)and striatal volume,(ii)extend these findings to female individuals,and(iii)employ multivariate and mediation models to determine common brain structural representations of IGD and social anxiety(assessed by the Liebowitz Social Anxiety Scale).Results:In line with the original study,the voxel-wise analyses revealed a negative association between IGD and volumes of the bilateral caudate.Going beyond the earlier study investigating only male participants,the present study demonstrates that the association in the right caudate was comparable in both the male and the female subsamples.Further examination using themultivariate approach revealed regionally different associations between IGD and social anxiety with striatal density representations in the dorsal striatum(caudate)and ventral striatum(nucleus accumbens).Higher levels of IGD were associated with higher social anxiety and the association was critically mediated by the multivariate neurostructural density variations of the striatum.Conclusions:Altered striatal volumes may represent a replicable and generalizable marker of IGD symptoms.However,exploratory multivariate analyses revealed more complex and regional specific associations between striatal density and IGD as well as social anxiety symptoms.Variations in both tendencies may share common structural brain representations,which mediate the association between increased IGD and social anxiety.展开更多
文摘We propose a method to determine the thickness of non-edge-on disk galaxies from their observed structure of spiral arms, based on the solution of the truly three-dimensional Poisson's equation for a logarithmic disturbance of density and under the condition where the self-consistency of the density wave theory is no longer valid. From their measured number of arms, pitch angle and location of the innermost point of the spiral arms, we derive and present the thicknesses of 34 spiral galaxies.
文摘OBJECTIVE To observe the pattern of changes in the proliferation and apoptosis at different stages of large bowel carcinoma in mice, and to explore the effects of the imbalance of apoptosis and proliferation at different stages of large-intestine carcinogenesis.METHODS An experimental animal model for large intestine carcinogenesis of KUNMING-strain mice was used. The carcinomas were induced by subcuteneous injection of dimethylhydrazine (DMH) and the distribution and density changes of proliferating and apoptotic cells observed through multistages toward cancer formation. The animals were killed in groups at the 12th, 18th, 24th,and 32nd weeks of carcinoma induction. The apoptotic and proliferating cells were labeled separately using TUNEL and PCNA immunohistochemical staining methodsRF, RESULTS In the normal mouse mucosa, all the apoptotic cells were situated in the superficial layers, however, the proliferating cells were situated in the basement layers, and the amount of both were small. In the early stage of carcinoma induction, the proliferation and the apoptotic cells slightly increased in amount, but there were no obvious changes in their ratio. In the medium stage, the densities of both distinctly increased, but there were no obvious changes in the ratio. In the late stage, the densities of the proliferating and the apoptotic cells in the non-carcinoma mucosa were higher than those at other stages. The proliferating cells in the dysplastic mucosa increased progressively with the increasing degree of the lesions. Although the apoptotic cells increased, their changes did not occur with the degree of the lesions. Their ratio showed a decreasing tendency with the degree of the lesions.CONCLUSIONS (①The presence of an imbalance between cell proliferation and apoptosis was confirmed in the course of large intestine carcinogenesis in a mouse model. ②In the early stage of carcinoma induction both proliferation and apoptosis were at a low level; in the medium stage, they were both at a high level; and in the late stage (that is in carcinoma), proliferation was at a very high level, while apoptosis was at a low level. ③The proliferating cells increased progressively with the degree of dysplasia. There were no obvious changes in the apoptotic cells and their ratio to the proliferating cell sshowed a progressively increasing tendency. ④In the stage of cancer formation, the most essential change was the excessive decrease in the ratio of apoptosis to proliferation. These results support the hypothesis of "Cell Selective Proliferation", which was raised by authors previously in a study on human large bowel carcinoma.
基金This work was supported by the National Natural Science Foundation of China(NSFC,no.8221101268,no.82271583,no.32250610208)the National Key Research and Development Program of China(grant no.2018YFA0701400).
文摘Background:Brain structural alterations of the striatum have been frequently observed in internet gaming disorder(IGD);however,the replicability of the results and the associations with social-affective dysregulations such as social anxiety remain to be determined.Methods:The present study combined a dimensional neuroimaging approach with both voxel-wise and data-driven multivariate approaches to(i)replicate our previous results on a negative association between IGD symptom load(assessed by the Internet Gaming Disorder Scale-Short Form)and striatal volume,(ii)extend these findings to female individuals,and(iii)employ multivariate and mediation models to determine common brain structural representations of IGD and social anxiety(assessed by the Liebowitz Social Anxiety Scale).Results:In line with the original study,the voxel-wise analyses revealed a negative association between IGD and volumes of the bilateral caudate.Going beyond the earlier study investigating only male participants,the present study demonstrates that the association in the right caudate was comparable in both the male and the female subsamples.Further examination using themultivariate approach revealed regionally different associations between IGD and social anxiety with striatal density representations in the dorsal striatum(caudate)and ventral striatum(nucleus accumbens).Higher levels of IGD were associated with higher social anxiety and the association was critically mediated by the multivariate neurostructural density variations of the striatum.Conclusions:Altered striatal volumes may represent a replicable and generalizable marker of IGD symptoms.However,exploratory multivariate analyses revealed more complex and regional specific associations between striatal density and IGD as well as social anxiety symptoms.Variations in both tendencies may share common structural brain representations,which mediate the association between increased IGD and social anxiety.
