The consequences of sharp rise in atmospheric carbon dioxide concentration ([CO2]) and global warming on vascular plants have raised great concerns, but researches focusing on non-vascular epiphytes remain sparse. We ...The consequences of sharp rise in atmospheric carbon dioxide concentration ([CO2]) and global warming on vascular plants have raised great concerns, but researches focusing on non-vascular epiphytes remain sparse. We transplanted nine common cryptogamic epiphyte species (3 bryophytes, 6 lichens) from field sites to growth chambers (control, elevated [CO2], elevated temperature, elevated [CO2] and temperature) and monitored their growth and health at regular intervals in a subtropical montane forest in Ailao Mountains in southwestern China. Our results implied a dim future for nonvascular epiphytes, especially lichens, in a warming world. The initial rise in temperature and decrease in water availability from field sites to the control chamber had remarkable negative impacts on growth and health of nonvascular epiphytes, many of which turned brown or died back. Although elevated [CO2] in chambers had no significant effects on growth of any of the experimental species, further warming caused significant negative impacts on growth of Lobaria retigera (Bory) Trev. In addition, elevated [CO2] and temperature have a significant interaction on growth of four experimental lichens. Considering the ecological importance of epiphytic bryophytes and lichens for the subtropical montane forest ecosystems and high sensitivity to environmental changes, people may underestimate global change impacts to nonvascular epiphytes, or even the whole forest ecosystems.展开更多
The anatomy of the penile urethra presents additional challenges when compared to other urethral segments during open stricture surgery particularly because of its unsuitability for excision and primary anastomosis an...The anatomy of the penile urethra presents additional challenges when compared to other urethral segments during open stricture surgery particularly because of its unsuitability for excision and primary anastomosis and its relatively deficient corpus spongiosum. Stricture aetiology, location, length and previous surgical intervention remain the primary factors influencing the choice of penile urethroplasty technique. We have identified what we feel are the most important challenges and controversies in penile urethral stricture reconstruction, namely the use of flaps vs grafts, use of skin or oral mucosal tissue for augmentation/substitution and when a single or a staged approach is indicated to give the best possible outcome. The management of more complex cases such as panurethral lichen-sclerosus strictures and hypospadias "cripples" is outlined and potential developments for the future are presented.展开更多
大气元素沉降的地衣移植法监测常将地衣样品移植于乔木冠层下,但冠层有无与移植时长对地衣元素组成的影响研究不多。本研究将河北省偏远地区的中国树花(Ramalina sinensis)移植于污染区,基于元素含量增高倍数EC(exposed to control rat...大气元素沉降的地衣移植法监测常将地衣样品移植于乔木冠层下,但冠层有无与移植时长对地衣元素组成的影响研究不多。本研究将河北省偏远地区的中国树花(Ramalina sinensis)移植于污染区,基于元素含量增高倍数EC(exposed to control ratio)评估了55种元素的生物积累程度,检验了冠层(2水平:有冠层或无冠层)和移植时长(3水平:7、8或9个月)对地衣元素含量的影响。结果显示,中国树花的元素背景含量低于已有研究中地衣元素含量的背景值/基线值,有效反映了背景区较低的大气污染程度。中国树花适用于除Co和Hg(二者含量的背景噪声过高)之外的53种元素的大气沉降监测。移植后绝大多数元素含量显著高于背景区,其中交通相关元素Pb和Sb为“极重度积累”,与农业活动和植物生理活性有关的元素(As、K、P、S和Se)以及Ag和Ge为“无积累”或“轻度积累”,其他44种元素(Al、B、Ba、Be、Bi、Ca、Cd、Ce、Cr、Cs、Cu、Dy、Er、Eu、Fe、Gd、Ho、La、Li、Lu、Mg、Mn、Mo、Na、Nb、Nd、Ni、Pr、Rb、Tb、Sc、Si、Sm、Sn、Sr、Th、Ti、Tl、Tm、U、V、Y、Yb和Zn)为“中度积累”,表明移植区大气污染程度较高,交通排放贡献大。冠层和移植时长对中国树花元素含量的影响具有元素特异性:26种元素的含量或因冠层淋溶作用而在冠层下高于无冠层,Pb含量或因冠层截留作用而呈相反格局;移植时长超过7个月后,绝大多数元素(41种)含量不再增加,11种元素含量呈增高趋势,Ni含量呈下降趋势。表明利用地衣移植法进行大气元素沉降监测时,冠层有无需保持一致,且移植时间不可过长。展开更多
文摘The consequences of sharp rise in atmospheric carbon dioxide concentration ([CO2]) and global warming on vascular plants have raised great concerns, but researches focusing on non-vascular epiphytes remain sparse. We transplanted nine common cryptogamic epiphyte species (3 bryophytes, 6 lichens) from field sites to growth chambers (control, elevated [CO2], elevated temperature, elevated [CO2] and temperature) and monitored their growth and health at regular intervals in a subtropical montane forest in Ailao Mountains in southwestern China. Our results implied a dim future for nonvascular epiphytes, especially lichens, in a warming world. The initial rise in temperature and decrease in water availability from field sites to the control chamber had remarkable negative impacts on growth and health of nonvascular epiphytes, many of which turned brown or died back. Although elevated [CO2] in chambers had no significant effects on growth of any of the experimental species, further warming caused significant negative impacts on growth of Lobaria retigera (Bory) Trev. In addition, elevated [CO2] and temperature have a significant interaction on growth of four experimental lichens. Considering the ecological importance of epiphytic bryophytes and lichens for the subtropical montane forest ecosystems and high sensitivity to environmental changes, people may underestimate global change impacts to nonvascular epiphytes, or even the whole forest ecosystems.
文摘The anatomy of the penile urethra presents additional challenges when compared to other urethral segments during open stricture surgery particularly because of its unsuitability for excision and primary anastomosis and its relatively deficient corpus spongiosum. Stricture aetiology, location, length and previous surgical intervention remain the primary factors influencing the choice of penile urethroplasty technique. We have identified what we feel are the most important challenges and controversies in penile urethral stricture reconstruction, namely the use of flaps vs grafts, use of skin or oral mucosal tissue for augmentation/substitution and when a single or a staged approach is indicated to give the best possible outcome. The management of more complex cases such as panurethral lichen-sclerosus strictures and hypospadias "cripples" is outlined and potential developments for the future are presented.
文摘大气元素沉降的地衣移植法监测常将地衣样品移植于乔木冠层下,但冠层有无与移植时长对地衣元素组成的影响研究不多。本研究将河北省偏远地区的中国树花(Ramalina sinensis)移植于污染区,基于元素含量增高倍数EC(exposed to control ratio)评估了55种元素的生物积累程度,检验了冠层(2水平:有冠层或无冠层)和移植时长(3水平:7、8或9个月)对地衣元素含量的影响。结果显示,中国树花的元素背景含量低于已有研究中地衣元素含量的背景值/基线值,有效反映了背景区较低的大气污染程度。中国树花适用于除Co和Hg(二者含量的背景噪声过高)之外的53种元素的大气沉降监测。移植后绝大多数元素含量显著高于背景区,其中交通相关元素Pb和Sb为“极重度积累”,与农业活动和植物生理活性有关的元素(As、K、P、S和Se)以及Ag和Ge为“无积累”或“轻度积累”,其他44种元素(Al、B、Ba、Be、Bi、Ca、Cd、Ce、Cr、Cs、Cu、Dy、Er、Eu、Fe、Gd、Ho、La、Li、Lu、Mg、Mn、Mo、Na、Nb、Nd、Ni、Pr、Rb、Tb、Sc、Si、Sm、Sn、Sr、Th、Ti、Tl、Tm、U、V、Y、Yb和Zn)为“中度积累”,表明移植区大气污染程度较高,交通排放贡献大。冠层和移植时长对中国树花元素含量的影响具有元素特异性:26种元素的含量或因冠层淋溶作用而在冠层下高于无冠层,Pb含量或因冠层截留作用而呈相反格局;移植时长超过7个月后,绝大多数元素(41种)含量不再增加,11种元素含量呈增高趋势,Ni含量呈下降趋势。表明利用地衣移植法进行大气元素沉降监测时,冠层有无需保持一致,且移植时间不可过长。
