[Objective]The aim was to introduce T-DNA into watermelon for its molecular marker research.[Method]Based on the method of foreign DNA introduced to Arabidopsis thaliana via dipping flowers,the stigma smear was used t...[Objective]The aim was to introduce T-DNA into watermelon for its molecular marker research.[Method]Based on the method of foreign DNA introduced to Arabidopsis thaliana via dipping flowers,the stigma smear was used to transfer T-DNA into watermelon and its molecular marker research was carried out.[Result]The ideal transformed species was ZXG01078 for the highest fruit setting rate and the most deviant seedlings.The best concentration of kanamycin for treating watermelon seeds was 500-700 mg/L with differences among the species.The best position was spire leaf or young leaf and the best concentration of kanamycin for treating the watermelon leaf was 4 000-8 000 mg/L with no significant difference among species.The steadily variation appearing of growing pointless and conjoined twin seedlings indicated that the normal growth had been interfered by foreign DNA in the progeny.[Conclusion]This study had provided basis for the further research on watermelon.展开更多
In steel-concrete composite twin-girder decks, wide concrete slab would undergo significant shear lag warping effect, including positive and negative. Some researchers have investigated the positive shear lag of compo...In steel-concrete composite twin-girder decks, wide concrete slab would undergo significant shear lag warping effect, including positive and negative. Some researchers have investigated the positive shear lag of composite decks by means of one-dimensional line model, while the studies on the negative shear lag have not yet been reported until now. In this study, a new one-dimensional analytical model of composite twin-girder decks is first proposed based on the model proposed by Dezi et al. Besides slab shear lag effect and partial connection at slab-girder interface which have been included in the model of Dezi et al., the particularity of the proposed model relies on its ability to account for variation characteristic of cross-section. Verification of the analytical model is later conducted through comparison of results from the analytical analysis and elaborate FE analysis for a simply supported composite deck with increasing depth and a two-span continuous one with decreasing depth. Finally, three kinds of structural forms of composite twin-girder decks, including cantilever, simply supported and continuous decks, are selected to carry out the analysis of positive and negative shear lag behaviors by means of the analytical model. The influences of cross-sectional variation characteristic and load type on positive and negative shear lag behaviors are mainly investigated. Additionally, a new definition on effective width for considering simultaneously positive and negative shear lag behaviors is proposed. The results from the proposed analytical model and EC4 specification are compared to provide suggestions for designers and checkers. In this study, the proposed analytical model can provide a powerful numerical tool for researchers to conduct the further investigation, and the analysis on shear lag and effective width can assist in design analysis of composite twin-girder decks.展开更多
Objective： To explore whether there exist differences in cognitive development between singletons and twins born after in vitro fertilization （IVF） or intracytoplasmic sperm injection （ICSI）. Methods： A total of...Objective： To explore whether there exist differences in cognitive development between singletons and twins born after in vitro fertilization （IVF） or intracytoplasmic sperm injection （ICSI）. Methods： A total of 566 children were recruited for the study, including 388 children （singletons, n=175; twins, n=213） born after IVF and 178 children （singletons, n=87; twins, n=91 ） born after ICSI. The cognitive development was assessed using the Chinese-Wechsler Intelligence Scale for Children （C-WISC）. Results： For all pre-term offspring, all the intelligence quotient （IQ） items between singletons and twins showed no significant differences no matter if they were born after IVF or ICSI. There was a significant difference in the cognitive development of IVF-conceived full-term singletons and twins. The twins born after IVF obtained significantly lower scores than the singletons in verbal IQ （containing information, picture ＆ vocabulary, arithmetic, picture completion, comprehension, and language）, performance IQ （containing maze, visual analysis, object assembly, and performance）, and full scale IQ （P〈0.05）. The cognitive development of full-term sin- gletons and twins born after ICSI did not show any significant differences. There was no significant difference between the parents of the singletons and twins in their characteristics where data were collected, including the age of the mothers, the current employment status, the educational backgrounds, and areas of residence. There were also no consistent differences in the duration of pregnancy, sex composition of the children, age, and height between sin- gletons and twins at the time of our study although there existed significant differences between the two groups in the sex composition of the full-term children born after ICSI （P〈0.05）. Conclusions： Compared to the full-term singletons born after IVF, the full-term twins have lower cognitive development. The cognitive development of full-term singletons and twins born after ICSI did not show any significant differences. For all pre-term offspring, singletons and twins born after IVF or ICSI, the results of the cognitive development showed no significant differences.展开更多
Mechanical cues present in the stem cell niche resulting from intracellular processes or external force sources significantly affect the basic functions of stem cells such as self-renewal and differentiation.Creation ...Mechanical cues present in the stem cell niche resulting from intracellular processes or external force sources significantly affect the basic functions of stem cells such as self-renewal and differentiation.Creation of artificial cellular matrices exhibiting intrinsic mechanical cues generated by mechanical movements remains scarce.Herein,we reported on mechanically dynamic hydrogel matrices undergoing photo-induced directional domain sliding movement and their role in regulating embryonic stem cell(ESC)differentiation.The mechanically dynamic hydrogels were prepared via the self-assembly of an alternating hydrophilic and hydrophobic peptide with a photocaged cysteine residue.Upon light irradiation,the assemblies of the caged peptide were converted to non-equilibrated non-caged peptide bilayers that underwent the directional domain sliding motion induced by the thermodynamically favorable hydrophobic collapse transition.Culturing murine ESCs on the mechanically dynamic hydrogels resulted in biased differentiation toward the ectodermal lineage.We further showed that the mechanically dynamic hydrogels stimulated the translocation of a mechanotransduction protein Yes-associated protein(YAP)into the nucleus,implicating a potential mechanotransduction mechanism for the biased differentiation of ESCs.The finding of the biased ectodermal differentiation of ESCs induced by the mechanically dynamic hydrogels implies the great potency of the mechanically dynamic hydrogels as biomaterials for disease therapy and tissue regeneration in the future.展开更多
基金Supported by Crop Germplasm Resources Protection Project of Ministry of Agriculture(NB08-2130135-44)National Science and Technology Infrastructure Project(2005DKA21001-23)
文摘[Objective]The aim was to introduce T-DNA into watermelon for its molecular marker research.[Method]Based on the method of foreign DNA introduced to Arabidopsis thaliana via dipping flowers,the stigma smear was used to transfer T-DNA into watermelon and its molecular marker research was carried out.[Result]The ideal transformed species was ZXG01078 for the highest fruit setting rate and the most deviant seedlings.The best concentration of kanamycin for treating watermelon seeds was 500-700 mg/L with differences among the species.The best position was spire leaf or young leaf and the best concentration of kanamycin for treating the watermelon leaf was 4 000-8 000 mg/L with no significant difference among species.The steadily variation appearing of growing pointless and conjoined twin seedlings indicated that the normal growth had been interfered by foreign DNA in the progeny.[Conclusion]This study had provided basis for the further research on watermelon.
基金supported by the Fundamental Research Fund for the Central Universities(Grant No.2015JBM069)the Research Fund for Talented Scholars of Beijing Jiaotong University(Grant No.2016RC026)
文摘In steel-concrete composite twin-girder decks, wide concrete slab would undergo significant shear lag warping effect, including positive and negative. Some researchers have investigated the positive shear lag of composite decks by means of one-dimensional line model, while the studies on the negative shear lag have not yet been reported until now. In this study, a new one-dimensional analytical model of composite twin-girder decks is first proposed based on the model proposed by Dezi et al. Besides slab shear lag effect and partial connection at slab-girder interface which have been included in the model of Dezi et al., the particularity of the proposed model relies on its ability to account for variation characteristic of cross-section. Verification of the analytical model is later conducted through comparison of results from the analytical analysis and elaborate FE analysis for a simply supported composite deck with increasing depth and a two-span continuous one with decreasing depth. Finally, three kinds of structural forms of composite twin-girder decks, including cantilever, simply supported and continuous decks, are selected to carry out the analysis of positive and negative shear lag behaviors by means of the analytical model. The influences of cross-sectional variation characteristic and load type on positive and negative shear lag behaviors are mainly investigated. Additionally, a new definition on effective width for considering simultaneously positive and negative shear lag behaviors is proposed. The results from the proposed analytical model and EC4 specification are compared to provide suggestions for designers and checkers. In this study, the proposed analytical model can provide a powerful numerical tool for researchers to conduct the further investigation, and the analysis on shear lag and effective width can assist in design analysis of composite twin-girder decks.
基金Project supported by the Program for Zhejiang Leading Team of S&T Innovation(No.2011R50013-14)the National Basic Research Program(973)of China(No.2014CB943302)+1 种基金the Major Science and Technology Programs of the Department of Science and Technology of Zhejiang Province(No.2010C13028)the National Science & Technology Pillar Program during the 12th Five-Year Plan Period(No.2012BAI32B01),China
文摘Objective： To explore whether there exist differences in cognitive development between singletons and twins born after in vitro fertilization （IVF） or intracytoplasmic sperm injection （ICSI）. Methods： A total of 566 children were recruited for the study, including 388 children （singletons, n=175; twins, n=213） born after IVF and 178 children （singletons, n=87; twins, n=91 ） born after ICSI. The cognitive development was assessed using the Chinese-Wechsler Intelligence Scale for Children （C-WISC）. Results： For all pre-term offspring, all the intelligence quotient （IQ） items between singletons and twins showed no significant differences no matter if they were born after IVF or ICSI. There was a significant difference in the cognitive development of IVF-conceived full-term singletons and twins. The twins born after IVF obtained significantly lower scores than the singletons in verbal IQ （containing information, picture ＆ vocabulary, arithmetic, picture completion, comprehension, and language）, performance IQ （containing maze, visual analysis, object assembly, and performance）, and full scale IQ （P〈0.05）. The cognitive development of full-term sin- gletons and twins born after ICSI did not show any significant differences. There was no significant difference between the parents of the singletons and twins in their characteristics where data were collected, including the age of the mothers, the current employment status, the educational backgrounds, and areas of residence. There were also no consistent differences in the duration of pregnancy, sex composition of the children, age, and height between sin- gletons and twins at the time of our study although there existed significant differences between the two groups in the sex composition of the full-term children born after ICSI （P〈0.05）. Conclusions： Compared to the full-term singletons born after IVF, the full-term twins have lower cognitive development. The cognitive development of full-term singletons and twins born after ICSI did not show any significant differences. For all pre-term offspring, singletons and twins born after IVF or ICSI, the results of the cognitive development showed no significant differences.
基金supported by the National Key R&D Program of China (2018YFC1313003)the Fundamental Research Funds for the Central Universities+1 种基金the National Natural Science Foundation of China (21774065 and 31622038)the Natural Science Foundation of Tianjin (18JCQNJC14100 and 18JCJQJC48400)
文摘Mechanical cues present in the stem cell niche resulting from intracellular processes or external force sources significantly affect the basic functions of stem cells such as self-renewal and differentiation.Creation of artificial cellular matrices exhibiting intrinsic mechanical cues generated by mechanical movements remains scarce.Herein,we reported on mechanically dynamic hydrogel matrices undergoing photo-induced directional domain sliding movement and their role in regulating embryonic stem cell(ESC)differentiation.The mechanically dynamic hydrogels were prepared via the self-assembly of an alternating hydrophilic and hydrophobic peptide with a photocaged cysteine residue.Upon light irradiation,the assemblies of the caged peptide were converted to non-equilibrated non-caged peptide bilayers that underwent the directional domain sliding motion induced by the thermodynamically favorable hydrophobic collapse transition.Culturing murine ESCs on the mechanically dynamic hydrogels resulted in biased differentiation toward the ectodermal lineage.We further showed that the mechanically dynamic hydrogels stimulated the translocation of a mechanotransduction protein Yes-associated protein(YAP)into the nucleus,implicating a potential mechanotransduction mechanism for the biased differentiation of ESCs.The finding of the biased ectodermal differentiation of ESCs induced by the mechanically dynamic hydrogels implies the great potency of the mechanically dynamic hydrogels as biomaterials for disease therapy and tissue regeneration in the future.
