Nanog is a newly identified homeodomain gene that functions to sustain the pluripotency of embryonic stem cells.However,the molecular mechanism through which nanog regulates stem cell pluripotency remains unknown.Mous...Nanog is a newly identified homeodomain gene that functions to sustain the pluripotency of embryonic stem cells.However,the molecular mechanism through which nanog regulates stem cell pluripotency remains unknown.Mouse nanog encodes a polypeptide of 305 residues with a divergent homeodomain similar to those in the NK-2 family.The rest ofnanog contains no apparent homology to any known proteins characterized so far.It is hypothesized that nanog encodes a transcription factor that regulates stem cell pluripotency by switching on or off target genes.To test this hypothesis,we constructed fusion proteins between nanog and DNA binding domains of the yeast transcription factor Gal4 and tested the transactivation potentials of these constructs.Our data demonstrate that both regions N- and C- terminal to the homeodomain have transcription activities.Despite the fact that it contains no apparent transactivation motifs,the C-terminal domain is about 7 times as active as the N-terminal one.This unique arrangement of dual transactivators may confer nanog the flexibility and specificity to regulate downstream genes critical for both pluripotency and differentiation of stem cells.展开更多
Considering the density dependence of quark mass, we investigate the phase transition between the （unpaired） strange quark matter and the color-flavor-locked matter, which are supposed to be two candidates for the g...Considering the density dependence of quark mass, we investigate the phase transition between the （unpaired） strange quark matter and the color-flavor-locked matter, which are supposed to be two candidates for the ground state of strongly interacting matter. We lind that if the current mass of strange quark m, is smmall, the strange quark matter remains stable unless the baryon density is very high. If m, is large, the phase transition from the strange quark matter to the color-flavor-locked matter in particular to its gapless phase is found to be different from the results predicted by previous works. A complicated phase diagram of three-flavor quark matter is presented, in which the color-flavor-locked phase region is suppressed for moderate densities.展开更多
The restructuring of old industrial areas has been receiving much attention in regional development studies both in industrialized and emerging economies. Although ample Chinese-speaking studies have been published on...The restructuring of old industrial areas has been receiving much attention in regional development studies both in industrialized and emerging economies. Although ample Chinese-speaking studies have been published on the topic, most of them suffer from paying too little attention to dynamic multi-scalar interactions between firms, institutions, policies and places, as well as a too strong focus on individual cases. They also mostly disregard internationally recognized concepts and theories in the field. Based on these internationally recognized modern concepts, this paper therefore puts forward some potential avenues for future research on the evolution of old industrial areas in China, which should overcome existing deficits in the Chinese-speaking literature. It suggests that some evolutionary economic geography concepts such as path dependence, lock-in, path creation, relatedness, as well as multi-scalar institutional and leadership approaches have useful potentials to better understand the evolutionary processes and mechanisms of old industrial areas in China.展开更多
基金supported in part by the Tsinghua University BaiRen Scholar Program,NSFC 30270287the 973 Project--2001CB5101 from The Ministry of Science and Technology of China.
文摘Nanog is a newly identified homeodomain gene that functions to sustain the pluripotency of embryonic stem cells.However,the molecular mechanism through which nanog regulates stem cell pluripotency remains unknown.Mouse nanog encodes a polypeptide of 305 residues with a divergent homeodomain similar to those in the NK-2 family.The rest ofnanog contains no apparent homology to any known proteins characterized so far.It is hypothesized that nanog encodes a transcription factor that regulates stem cell pluripotency by switching on or off target genes.To test this hypothesis,we constructed fusion proteins between nanog and DNA binding domains of the yeast transcription factor Gal4 and tested the transactivation potentials of these constructs.Our data demonstrate that both regions N- and C- terminal to the homeodomain have transcription activities.Despite the fact that it contains no apparent transactivation motifs,the C-terminal domain is about 7 times as active as the N-terminal one.This unique arrangement of dual transactivators may confer nanog the flexibility and specificity to regulate downstream genes critical for both pluripotency and differentiation of stem cells.
基金The project supported by National Natural Science Foundation of China under Grant No. 10405012
文摘Considering the density dependence of quark mass, we investigate the phase transition between the （unpaired） strange quark matter and the color-flavor-locked matter, which are supposed to be two candidates for the ground state of strongly interacting matter. We lind that if the current mass of strange quark m, is smmall, the strange quark matter remains stable unless the baryon density is very high. If m, is large, the phase transition from the strange quark matter to the color-flavor-locked matter in particular to its gapless phase is found to be different from the results predicted by previous works. A complicated phase diagram of three-flavor quark matter is presented, in which the color-flavor-locked phase region is suppressed for moderate densities.
基金Under the auspices of National High-level University Overseas Ph D Program by China Scholarship Council(CSC)Ministry of Education of China(No.2011614011)
文摘The restructuring of old industrial areas has been receiving much attention in regional development studies both in industrialized and emerging economies. Although ample Chinese-speaking studies have been published on the topic, most of them suffer from paying too little attention to dynamic multi-scalar interactions between firms, institutions, policies and places, as well as a too strong focus on individual cases. They also mostly disregard internationally recognized concepts and theories in the field. Based on these internationally recognized modern concepts, this paper therefore puts forward some potential avenues for future research on the evolution of old industrial areas in China, which should overcome existing deficits in the Chinese-speaking literature. It suggests that some evolutionary economic geography concepts such as path dependence, lock-in, path creation, relatedness, as well as multi-scalar institutional and leadership approaches have useful potentials to better understand the evolutionary processes and mechanisms of old industrial areas in China.
