Rhododendron meddianum is a critically endangered species with important ornamental value and is also a plant species with extremely small populations.In this study,we used double digest restriction-siteassociated DNA...Rhododendron meddianum is a critically endangered species with important ornamental value and is also a plant species with extremely small populations.In this study,we used double digest restriction-siteassociated DNA sequencing(ddRAD)technology to assess the genetic diversity,genetic structure and demographic history of the three extant populations of R.meddianum.Analysis of SNPs indicated that R.meddianum populations have a high genetic diversity(p?0.0772±0.0024,HE?0.0742±0.002).Both FST values(0.1582e0.2388)and AMOVA showed a moderate genetic differentiation among the R.meddianum populations.Meanwhile,STRUCTURE,PCoA and NJ trees indicated that the R.meddianum samples were clustered into three distinct genetic groups.Using the stairway plot,we found that R.meddianum underwent a population bottleneck about 70,000 years ago.Furthermore,demographic models of R.meddianum and its relative,Rhododendron cyanocarpum,revealed that these species diverged about 3.05(2.21e5.03)million years ago.This divergence may have been caused by environmental changes that occurred after the late Pliocene,e.g.,the Asian winter monsoon intensified,leading to a drier climate.Based on these findings,we recommend that R.meddianum be conserved through in situ,ex situ approaches and that its seeds be collected for germplasm.展开更多
We use the label-free microsphere-assisted microscopy to image low-contrast hexagonally close-packed polystyrene nanoparticle arrays with diameters of 300 and 250 nm.When a nanoparticle array is directly placed on a g...We use the label-free microsphere-assisted microscopy to image low-contrast hexagonally close-packed polystyrene nanoparticle arrays with diameters of 300 and 250 nm.When a nanoparticle array is directly placed on a glass slide,it cannot be distinguished.If a 30-nm-thick Ag film is deposited on the surface of a nanoparticle array,the nanoparticle array with nanoparticle diameters of 300 and 250 nm can be distinguished.In addition,the Talbot effect of the 300-nm-diameter nanoparticle array is also observed.If a nanoparticle sample is assembled on a glass slide deposited with a 30-nm-thick Ag film,an array of 300-nm-diameter nanoparticles can be discerned.We propose that in microsphere-assisted microscopy imaging,the resolution can be improved by the excitation of surface plasmon polaritons(SPPs) on the sample surface or at the sample/substrate interface,and a higher near-field intensity due to the excited SPPs would benefit the resolution improvement.Our study of label-free super-resolution imaging of low-contrast objects will promote the applications of microsphere-assisted microscopy in life sciences.展开更多
Objective:To investigate the effects of endometrial stimulation timings and techniques on pregnancy outcomes in patients without prior embryo transfer(ET).Methods:We included a total of 10 studies related to the impac...Objective:To investigate the effects of endometrial stimulation timings and techniques on pregnancy outcomes in patients without prior embryo transfer(ET).Methods:We included a total of 10 studies related to the impact of endometrial stimulation on the pregnancy outcome of infertile patients with the first ET from 2010 to 2019.These studies were found by searching databases including China Science and Technology Journal Database(VIP),Chinese Biological Med(CBM),Chinese Medical Current Content(CMCC),China National Knowledge Internet(CNKI),WanFang Med Online,Cochrane Library,Web of Science,PubMed,Medline,ScienceDirect,and EMBASE.A total of 1,983 cycles were included,of which 725 were cycles with endometrial stimulation.Clinical outcomes included clinical pregnancy,implantation,abortion,multiple pregnancy,and live birth rate.Results:The implantation rate(IR)was higher in the fresh cycle endometrial stimulation group than in the control group(relative risk[RR]=1.21,95%confidence interval[CI]=1.03-1.42;P=0.02),but there were no significant between-group differences in the live birth rate(LBR)and abortion rate(AR).Subgroup analysis showed that whether follicular or luteal endometrial stimulation was performed before the ET cycle had no effect on the clinical pregnancy outcome,and endometrial stimulation on the day of oocyte retrieval reduced the clinical pregnancy rate(CPR)(RR=0.37,95%CI=0.19-0.75;P=0.005).Whether the technique involved the use of a curette or catheter,there was no significant between-group difference in CPR.Conclusions:Fresh cycle endometrial stimulation can improve the embryo IR in patients without prior ET,but it cannot increase CPR,LBR,or AR.Subgroup analysis showed that different endometrial stimulation timings and techniques did not significantly improve CPR and that endometrial stimulation on the day of oocyte retrieval reduced CPR.展开更多
基金supported by the Fundamental Research Funds for the Central Non-profit Research Institution of the Chinese Academy of Forestry(Grant No.CAFYBB2019ZB007)the Biodiversity Survey and Assessment Project of the Ministry of Ecology and Environment,China(Grant No.2019HJ2096001006)+2 种基金the Ten Thousand Talent Program of Yunnan Province(Grant No.YNWRQNBJ-2019-010YNWR-QNBJ-2018-174)the Young and Middle-aged Academic and Technical Leader Reserve Talent Project of Yunnan Province(Grant No.2018HB066).
文摘Rhododendron meddianum is a critically endangered species with important ornamental value and is also a plant species with extremely small populations.In this study,we used double digest restriction-siteassociated DNA sequencing(ddRAD)technology to assess the genetic diversity,genetic structure and demographic history of the three extant populations of R.meddianum.Analysis of SNPs indicated that R.meddianum populations have a high genetic diversity(p?0.0772±0.0024,HE?0.0742±0.002).Both FST values(0.1582e0.2388)and AMOVA showed a moderate genetic differentiation among the R.meddianum populations.Meanwhile,STRUCTURE,PCoA and NJ trees indicated that the R.meddianum samples were clustered into three distinct genetic groups.Using the stairway plot,we found that R.meddianum underwent a population bottleneck about 70,000 years ago.Furthermore,demographic models of R.meddianum and its relative,Rhododendron cyanocarpum,revealed that these species diverged about 3.05(2.21e5.03)million years ago.This divergence may have been caused by environmental changes that occurred after the late Pliocene,e.g.,the Asian winter monsoon intensified,leading to a drier climate.Based on these findings,we recommend that R.meddianum be conserved through in situ,ex situ approaches and that its seeds be collected for germplasm.
基金Project supported by the National Natural Science Foundation of China(Grant No.61673287)。
文摘We use the label-free microsphere-assisted microscopy to image low-contrast hexagonally close-packed polystyrene nanoparticle arrays with diameters of 300 and 250 nm.When a nanoparticle array is directly placed on a glass slide,it cannot be distinguished.If a 30-nm-thick Ag film is deposited on the surface of a nanoparticle array,the nanoparticle array with nanoparticle diameters of 300 and 250 nm can be distinguished.In addition,the Talbot effect of the 300-nm-diameter nanoparticle array is also observed.If a nanoparticle sample is assembled on a glass slide deposited with a 30-nm-thick Ag film,an array of 300-nm-diameter nanoparticles can be discerned.We propose that in microsphere-assisted microscopy imaging,the resolution can be improved by the excitation of surface plasmon polaritons(SPPs) on the sample surface or at the sample/substrate interface,and a higher near-field intensity due to the excited SPPs would benefit the resolution improvement.Our study of label-free super-resolution imaging of low-contrast objects will promote the applications of microsphere-assisted microscopy in life sciences.
文摘Objective:To investigate the effects of endometrial stimulation timings and techniques on pregnancy outcomes in patients without prior embryo transfer(ET).Methods:We included a total of 10 studies related to the impact of endometrial stimulation on the pregnancy outcome of infertile patients with the first ET from 2010 to 2019.These studies were found by searching databases including China Science and Technology Journal Database(VIP),Chinese Biological Med(CBM),Chinese Medical Current Content(CMCC),China National Knowledge Internet(CNKI),WanFang Med Online,Cochrane Library,Web of Science,PubMed,Medline,ScienceDirect,and EMBASE.A total of 1,983 cycles were included,of which 725 were cycles with endometrial stimulation.Clinical outcomes included clinical pregnancy,implantation,abortion,multiple pregnancy,and live birth rate.Results:The implantation rate(IR)was higher in the fresh cycle endometrial stimulation group than in the control group(relative risk[RR]=1.21,95%confidence interval[CI]=1.03-1.42;P=0.02),but there were no significant between-group differences in the live birth rate(LBR)and abortion rate(AR).Subgroup analysis showed that whether follicular or luteal endometrial stimulation was performed before the ET cycle had no effect on the clinical pregnancy outcome,and endometrial stimulation on the day of oocyte retrieval reduced the clinical pregnancy rate(CPR)(RR=0.37,95%CI=0.19-0.75;P=0.005).Whether the technique involved the use of a curette or catheter,there was no significant between-group difference in CPR.Conclusions:Fresh cycle endometrial stimulation can improve the embryo IR in patients without prior ET,but it cannot increase CPR,LBR,or AR.Subgroup analysis showed that different endometrial stimulation timings and techniques did not significantly improve CPR and that endometrial stimulation on the day of oocyte retrieval reduced CPR.
