Within the last several decades,the scientific community has made substantial progress in elucidating the complex pathophysiology underlying spinal cord injury.However,despite the many advances using conventional mamm...Within the last several decades,the scientific community has made substantial progress in elucidating the complex pathophysiology underlying spinal cord injury.However,despite the many advances using conventional mammalian models,both cellular and axonal regeneration following spinal cord injury have remained out of reach.In this sense,turning to non-mammalian,regenerative species presents a unique opportunity to identify pro-regenerative cues and characterize a spinal cord microenvironment permissive to re-growth.Among the signaling pathways hypothesized to be dysregulated during spinal cord injury is the purinergic signaling system.In addition to its well-known role as energy currency in cells,ATP and its metabolites are small molecule neurotransmitters that mediate many diverse cellular processes within the central nervous system.While our understanding of the roles of the purinergic system following spinal cord injury is limited,this signaling pathway has been implicated in all injury-induced secondary processes,including cellular death,inflammation,reactive gliosis,and neural regeneration.Given that the purinergic system is also evolutionarily conserved between mammalian and non-mammalian species,comparisons of these roles may provide important insights into conditions responsible for recovery success.Here,we compare the secondary processes between key model species and the influence of purinergic signaling in each context.As our understanding of this signaling system and pro-regenerative conditions continues to evolve,so does the potential for the development of novel therapeutic interventions for spinal cord injury.展开更多
Aims We explore the possible role of leaf size/number trade-offs for the interpretation of leaf size dimorphism in dioecious plant species.Methods Total above-ground biomass(both male and female)for three herbaceous d...Aims We explore the possible role of leaf size/number trade-offs for the interpretation of leaf size dimorphism in dioecious plant species.Methods Total above-ground biomass(both male and female)for three herbaceous dioecious species and individual shoots(from both male and female plants)for three woody dioecious species were sampled to record individual leaf dry mass,number of leaves,dry mass of residual above-ground tissue(all remaining non-leaf biomass),number of flowers/inflorescences(for herbaceous species)and number of branches.Important Findings For two out of three woody species and two out of three herbaceous species examined,male plants produced smaller leaves but with higher leafing intensity—i.e.more leaves per unit of supporting(residual)shoot tissue or plant body mass—compared with females.Male and female plants,however,did not differ in shoot or plant body mass or branching intensity.We interpret these results as possible evidence for a dimorphic leaf deployment strategy that promotes both male and female function,respectively.In male plants,capacity as a pollen donor may be favored by selection for a broadly spaced floral display,hence favoring relatively high leafing intensity because this provides more numerous axillary meristems that can be deployed for flowering,thus requiring a relatively small leaf as a trade-off.In one herbaceous species,higher leafing intensity in males was associated with greater flower production than in females.In contrast,in female plants,selection favors a relatively large leaf,we propose,because this promotes greater capacity for localized photosynthate production,thus supporting the locally high energetic cost of axillary fruit and seed development,which in turn requires a relatively low leafing intensity as a trade-off.展开更多
Within the last several decades,the scientific community has made substantial progress in elucidating the complex pathophysiology underlying spinal cord injury.However,despite the many advances using conventional mamm...Within the last several decades,the scientific community has made substantial progress in elucidating the complex pathophysiology underlying spinal cord injury.However,despite the many advances using conventional mammalian models,both cellular and axonal regeneration following spinal cord injury have remained out of reach.In this sense,turning to non-mammalian,regenerative species presents a unique opportunity to identify pro-regenerative cues and chara cterize a spinal cord microenvironment permissive to re-growth.Among the signaling pathways hypothesized to be dysregulated during spinal cord injury is the purinergic signaling system.In addition to its well-known role as energy currency in cells,ATP and its metabolites are small molecule neurotransmitte rs that mediate many diverse cellular processes within the central nervous system.While our unde rstanding of the roles of the purinergic system following spinal cord injury is limited,this signaling pathway has been implicated in all injury-induced secondary processes,including cellular death,inflammation,reactive gliosis,and neural regeneration.Given that the purinergic system is also evolutionarily conserved between mammalian and non-mammalian species,comparisons of these roles may provide important insights into conditions responsible for recovery success.Here,we compare the secondary processes between key model species and the influence of purinergic signaling in each context.As our understanding of this signaling system and pro-regenerative conditions continues to evolve,so does the potential for the development of novel therapeutic interventions for spinal cord injury.展开更多
This paper aims at developing a "local-global" approach for various types of finite dimensional algebras, especially those related to Hecke algebras. The eventual intention is to apply the methods and applic...This paper aims at developing a "local-global" approach for various types of finite dimensional algebras, especially those related to Hecke algebras. The eventual intention is to apply the methods and applications developed here to the cross-characteristic representation theory of finite groups of Lie type. We first review the notions of quasi-hereditary and stratified algebras over a Noetherian commutative ring. We prove that many global properties of these algebras hold if and only if they hold locally at every prime ideal. When the commutative ring is sufficiently good, it is often sufficient to check just the prime ideals of height at most one. These methods are applied to construct certain generalized q-Schur algebras, proving they are often quasi-hereditary(the "good" prime case) but always stratified. Finally, these results are used to prove a triangular decomposition matrix theorem for the modular representations of Hecke algebras at good primes. In the bad prime case, the generalized q-Schur algebras are at least stratified, and a block triangular analogue of the good prime case is proved, where the blocks correspond to Kazhdan-Lusztig cells.展开更多
2009年7月24日，美国启动“竞争卓越”（Race to the Top，简称RTTT）计划，提供40多亿美元资助各州改革基础教育，尤其是加强数学和科学的学科教育改革。2011年3月，田纳西州获得美国“竞争卓越”计划的最高奖，并获得了为期四年的5．0...2009年7月24日，美国启动“竞争卓越”（Race to the Top，简称RTTT）计划，提供40多亿美元资助各州改革基础教育，尤其是加强数学和科学的学科教育改革。2011年3月，田纳西州获得美国“竞争卓越”计划的最高奖，并获得了为期四年的5．01亿美元资助经费（从2010—2011学年到2013—2014学年）。之后，在一系列法案（《2010年田纳西州捷足先登法案）（2010年田纳西州完成大学教育法案》等）的保障下，田纳西州开始实施一项全面综合的学校改革计划——《田纳西州捷足先登计划》（Tennessee First to the Top）。展开更多
Lower extremity amputation is increasingly prevalent in the United States,with growing numbers of patients suffering from diabetes and peripheral vascular disease.Amputation has significant functional sequelae as more...Lower extremity amputation is increasingly prevalent in the United States,with growing numbers of patients suffering from diabetes and peripheral vascular disease.Amputation has significant functional sequelae as more than half of patients are unable to ambulate at one year postoperatively.Improving mobility and decreasing chronic post-amputation pain can significantly improve the quality of life for these patients and reduce the cost burden on the healthcare system.Plastic and reconstructive surgery has been at the forefront of“reconstructive amputation”,in which nerve pedicles can be surgically guided to decrease painful neuroma formation as well as provide targets for myoelectric prosthesis use.We herein review post-amputation outcomes,epidemiology of chronic,post-amputation pain,and current treatments,including total muscle reinnervation and regenerative peripheral nerve interface,which are at the forefront of multidisciplinary treatment of lower extremity amputees.展开更多
Background:Black locust(BL,Robinia pseudoacacia)is considered a promising tree species for reforestation due to its great ability to fix nitrogen.However,after two or three coppice-harvesting rotations,the productivit...Background:Black locust(BL,Robinia pseudoacacia)is considered a promising tree species for reforestation due to its great ability to fix nitrogen.However,after two or three coppice-harvesting rotations,the productivity of BL declines.Whether soil microbial communities are affected and how these groups correlate with the nitrogen mineralization process across multi-generation stands remains unclear.Methods:We investigated the composition and structure of free-living nitrogen-fixing microorganisms(diazotrophs)by sequencing the marker gene nifH and compared these results to levels of soil nitrogen mineralization in the bulk soil and rhizosphere in black locust plantations on Mount Tai,China.Results:The results showed multi-generation BL coppice plantations decreased the total soil nitrogen(N),soil phosphorus(P),soil microbial biomass N(MBN),soil microbial biomass C(MBC),soil nitrification rate(Rn),soil ammonification rate(Ra),and net soil N mineralization rate(Rm),but significantly increased the concentration of soil NH_(4þ)-N to maintain sufficient NO_(3)^(-)N.The dominant species in bulk soil and rhizosphere changed from Rhodopseudomonas(22.62%and 15.76%),unclassified_c_Alphaproteobacteria(22.37%and 29.28%),unclassified_o_Rhizobiales(15.40%and 13.31%),Bradyrhizobium(12.00%and 11.74%)in seedling plantations to Bradyrhizobium(45.95%and 47.86%)and Rhodopseudomonas(43.56%and 41.84%)in coppice plantations,respectively.Mantel test and Redundancy analysis(RDA)revealed that Rn,Ra,and Rm were the most important factors shaping the diazotrophic communities.Conclusions:Our results suggest that the multi-generation BL coppice plantation can homogenize soil diazotrophic communities,which is mainly regulated by the available N loss caused by nitrogen mineralization.Strengthening the management technology of coppice plantations will provide more beneficial external consumption.展开更多
The Archean rocks in this area were divided into two groups: the lower Qianxi Group including Shangchuan Formation and Santunying Formation, and the upper Badaohe Group including Wangchang Formation, Wanzhangzi Format...The Archean rocks in this area were divided into two groups: the lower Qianxi Group including Shangchuan Formation and Santunying Formation, and the upper Badaohe Group including Wangchang Formation, Wanzhangzi Formation and Sanmendian Formation. The rocks of the Shangchuan Fro. are pyroxene展开更多
Background： Prematurely menopausal women have a doubled lifetime risk of dementia and a 5-fold increased risk of mortality from neuro- logical disorders, but the molecular mechanisms underlying these risks remain unc...Background： Prematurely menopausal women have a doubled lifetime risk of dementia and a 5-fold increased risk of mortality from neuro- logical disorders, but the molecular mechanisms underlying these risks remain unclear. We hypothesized that ischemia-induced amyloidogenesis may be enhanced in the hippocampus following prolonged loss of ovarian 17β-estradiol （E2）, which could contribute to these phenomena. Methods： The current study used a rat model of premature surgical menopause （10-week bilateral ovariectomy） with E2 therapy either initiated immediately （short-term E2 deprivation （STED）） or delayed to the end of the ovariectomy period （long-term E2 deprivation （LTED））. One week after continuous, subcutaneous E2 therapy, we subjected animals to 10-min global cerebral ischemia （GCI） to assess the effect of LTED on ischemia-induced amyloidogenesis in the hippocampal CA1. Results： The present study revealed that while hippocampal β-amyloid （Aβ） is not typically enhanced following GCI, there is a rapid, robust elevation of endogenous Aβ in LTED females after GCI. In STED females, we observed that GCI attenuates and E2 maintains A Disintegrin and Metalloprotease 10 （ADAM 10） expression in the hippocampal CA1, and concurrently, GCI increases and E2 decreases BACE1 levels in the same region. Intriguingly, however, we observed a loss of E2 regulation of ADAM 10, ADAM 17, and BACE 1 levels in the hippocampal CA I of LTED females, which provides mechanistic evidence for the enhanced post-ischemic Aβ load following LTED. We also observed loss of E2 regulation of tau hyperphosphorylation in LTED females subjected to GCI. Conclusion： Collectively, these studies partially explain the enhanced risk of dementia and mortality from neurological disorders seen in prematurely menopausal women and support timely initiation of E2 therapy to yield maximum neurological benefit.展开更多
基金supported by a Natural Sciences and Engineering Research Council operating grant(RGPIN-2019-07062).
文摘Within the last several decades,the scientific community has made substantial progress in elucidating the complex pathophysiology underlying spinal cord injury.However,despite the many advances using conventional mammalian models,both cellular and axonal regeneration following spinal cord injury have remained out of reach.In this sense,turning to non-mammalian,regenerative species presents a unique opportunity to identify pro-regenerative cues and characterize a spinal cord microenvironment permissive to re-growth.Among the signaling pathways hypothesized to be dysregulated during spinal cord injury is the purinergic signaling system.In addition to its well-known role as energy currency in cells,ATP and its metabolites are small molecule neurotransmitters that mediate many diverse cellular processes within the central nervous system.While our understanding of the roles of the purinergic system following spinal cord injury is limited,this signaling pathway has been implicated in all injury-induced secondary processes,including cellular death,inflammation,reactive gliosis,and neural regeneration.Given that the purinergic system is also evolutionarily conserved between mammalian and non-mammalian species,comparisons of these roles may provide important insights into conditions responsible for recovery success.Here,we compare the secondary processes between key model species and the influence of purinergic signaling in each context.As our understanding of this signaling system and pro-regenerative conditions continues to evolve,so does the potential for the development of novel therapeutic interventions for spinal cord injury.
基金Natural Sciences and Engineering Research Council of Canada Research Grant(14552 to L.W.A.).
文摘Aims We explore the possible role of leaf size/number trade-offs for the interpretation of leaf size dimorphism in dioecious plant species.Methods Total above-ground biomass(both male and female)for three herbaceous dioecious species and individual shoots(from both male and female plants)for three woody dioecious species were sampled to record individual leaf dry mass,number of leaves,dry mass of residual above-ground tissue(all remaining non-leaf biomass),number of flowers/inflorescences(for herbaceous species)and number of branches.Important Findings For two out of three woody species and two out of three herbaceous species examined,male plants produced smaller leaves but with higher leafing intensity—i.e.more leaves per unit of supporting(residual)shoot tissue or plant body mass—compared with females.Male and female plants,however,did not differ in shoot or plant body mass or branching intensity.We interpret these results as possible evidence for a dimorphic leaf deployment strategy that promotes both male and female function,respectively.In male plants,capacity as a pollen donor may be favored by selection for a broadly spaced floral display,hence favoring relatively high leafing intensity because this provides more numerous axillary meristems that can be deployed for flowering,thus requiring a relatively small leaf as a trade-off.In one herbaceous species,higher leafing intensity in males was associated with greater flower production than in females.In contrast,in female plants,selection favors a relatively large leaf,we propose,because this promotes greater capacity for localized photosynthate production,thus supporting the locally high energetic cost of axillary fruit and seed development,which in turn requires a relatively low leafing intensity as a trade-off.
基金a Natural Sciences and Engineering Research Council operating grant(RGPIN-2019-07062)。
文摘Within the last several decades,the scientific community has made substantial progress in elucidating the complex pathophysiology underlying spinal cord injury.However,despite the many advances using conventional mammalian models,both cellular and axonal regeneration following spinal cord injury have remained out of reach.In this sense,turning to non-mammalian,regenerative species presents a unique opportunity to identify pro-regenerative cues and chara cterize a spinal cord microenvironment permissive to re-growth.Among the signaling pathways hypothesized to be dysregulated during spinal cord injury is the purinergic signaling system.In addition to its well-known role as energy currency in cells,ATP and its metabolites are small molecule neurotransmitte rs that mediate many diverse cellular processes within the central nervous system.While our unde rstanding of the roles of the purinergic system following spinal cord injury is limited,this signaling pathway has been implicated in all injury-induced secondary processes,including cellular death,inflammation,reactive gliosis,and neural regeneration.Given that the purinergic system is also evolutionarily conserved between mammalian and non-mammalian species,comparisons of these roles may provide important insights into conditions responsible for recovery success.Here,we compare the secondary processes between key model species and the influence of purinergic signaling in each context.As our understanding of this signaling system and pro-regenerative conditions continues to evolve,so does the potential for the development of novel therapeutic interventions for spinal cord injury.
基金supported by a 2017 University of New South Wales Science Goldstar Grant(Jie Du)the Simons Foundation(Grant Nos. #359360(Brian Parshall) and #359363 (Leonard Scott))
文摘This paper aims at developing a "local-global" approach for various types of finite dimensional algebras, especially those related to Hecke algebras. The eventual intention is to apply the methods and applications developed here to the cross-characteristic representation theory of finite groups of Lie type. We first review the notions of quasi-hereditary and stratified algebras over a Noetherian commutative ring. We prove that many global properties of these algebras hold if and only if they hold locally at every prime ideal. When the commutative ring is sufficiently good, it is often sufficient to check just the prime ideals of height at most one. These methods are applied to construct certain generalized q-Schur algebras, proving they are often quasi-hereditary(the "good" prime case) but always stratified. Finally, these results are used to prove a triangular decomposition matrix theorem for the modular representations of Hecke algebras at good primes. In the bad prime case, the generalized q-Schur algebras are at least stratified, and a block triangular analogue of the good prime case is proved, where the blocks correspond to Kazhdan-Lusztig cells.
文摘2009年7月24日，美国启动“竞争卓越”（Race to the Top，简称RTTT）计划，提供40多亿美元资助各州改革基础教育，尤其是加强数学和科学的学科教育改革。2011年3月，田纳西州获得美国“竞争卓越”计划的最高奖，并获得了为期四年的5．01亿美元资助经费（从2010—2011学年到2013—2014学年）。之后，在一系列法案（《2010年田纳西州捷足先登法案）（2010年田纳西州完成大学教育法案》等）的保障下，田纳西州开始实施一项全面综合的学校改革计划——《田纳西州捷足先登计划》（Tennessee First to the Top）。
文摘Lower extremity amputation is increasingly prevalent in the United States,with growing numbers of patients suffering from diabetes and peripheral vascular disease.Amputation has significant functional sequelae as more than half of patients are unable to ambulate at one year postoperatively.Improving mobility and decreasing chronic post-amputation pain can significantly improve the quality of life for these patients and reduce the cost burden on the healthcare system.Plastic and reconstructive surgery has been at the forefront of“reconstructive amputation”,in which nerve pedicles can be surgically guided to decrease painful neuroma formation as well as provide targets for myoelectric prosthesis use.We herein review post-amputation outcomes,epidemiology of chronic,post-amputation pain,and current treatments,including total muscle reinnervation and regenerative peripheral nerve interface,which are at the forefront of multidisciplinary treatment of lower extremity amputees.
基金supported by the Agricultural Science and Technology Fund for Forestry Sci-tech Innovation Project of Shandong Province (No.2019LY005)the National Natural Science Foundation of China (No.31570705)+1 种基金Shandong Province Higher School Science and Technology Plan Project (No. J16LF09)and Shandong Province Natural Science Foundation (No. ZR2018PC006)
文摘Background:Black locust(BL,Robinia pseudoacacia)is considered a promising tree species for reforestation due to its great ability to fix nitrogen.However,after two or three coppice-harvesting rotations,the productivity of BL declines.Whether soil microbial communities are affected and how these groups correlate with the nitrogen mineralization process across multi-generation stands remains unclear.Methods:We investigated the composition and structure of free-living nitrogen-fixing microorganisms(diazotrophs)by sequencing the marker gene nifH and compared these results to levels of soil nitrogen mineralization in the bulk soil and rhizosphere in black locust plantations on Mount Tai,China.Results:The results showed multi-generation BL coppice plantations decreased the total soil nitrogen(N),soil phosphorus(P),soil microbial biomass N(MBN),soil microbial biomass C(MBC),soil nitrification rate(Rn),soil ammonification rate(Ra),and net soil N mineralization rate(Rm),but significantly increased the concentration of soil NH_(4þ)-N to maintain sufficient NO_(3)^(-)N.The dominant species in bulk soil and rhizosphere changed from Rhodopseudomonas(22.62%and 15.76%),unclassified_c_Alphaproteobacteria(22.37%and 29.28%),unclassified_o_Rhizobiales(15.40%and 13.31%),Bradyrhizobium(12.00%and 11.74%)in seedling plantations to Bradyrhizobium(45.95%and 47.86%)and Rhodopseudomonas(43.56%and 41.84%)in coppice plantations,respectively.Mantel test and Redundancy analysis(RDA)revealed that Rn,Ra,and Rm were the most important factors shaping the diazotrophic communities.Conclusions:Our results suggest that the multi-generation BL coppice plantation can homogenize soil diazotrophic communities,which is mainly regulated by the available N loss caused by nitrogen mineralization.Strengthening the management technology of coppice plantations will provide more beneficial external consumption.
文摘The Archean rocks in this area were divided into two groups: the lower Qianxi Group including Shangchuan Formation and Santunying Formation, and the upper Badaohe Group including Wangchang Formation, Wanzhangzi Formation and Sanmendian Formation. The rocks of the Shangchuan Fro. are pyroxene
基金supported by a Pre-doctoral Fellowship from the American Heart Association to ELS.(12PRE11530009)a Research Grant from the National Institute of Neurological Disorders and StrokeNational Institutes of Health,USA to DWB(NS050730)
文摘Background： Prematurely menopausal women have a doubled lifetime risk of dementia and a 5-fold increased risk of mortality from neuro- logical disorders, but the molecular mechanisms underlying these risks remain unclear. We hypothesized that ischemia-induced amyloidogenesis may be enhanced in the hippocampus following prolonged loss of ovarian 17β-estradiol （E2）, which could contribute to these phenomena. Methods： The current study used a rat model of premature surgical menopause （10-week bilateral ovariectomy） with E2 therapy either initiated immediately （short-term E2 deprivation （STED）） or delayed to the end of the ovariectomy period （long-term E2 deprivation （LTED））. One week after continuous, subcutaneous E2 therapy, we subjected animals to 10-min global cerebral ischemia （GCI） to assess the effect of LTED on ischemia-induced amyloidogenesis in the hippocampal CA1. Results： The present study revealed that while hippocampal β-amyloid （Aβ） is not typically enhanced following GCI, there is a rapid, robust elevation of endogenous Aβ in LTED females after GCI. In STED females, we observed that GCI attenuates and E2 maintains A Disintegrin and Metalloprotease 10 （ADAM 10） expression in the hippocampal CA1, and concurrently, GCI increases and E2 decreases BACE1 levels in the same region. Intriguingly, however, we observed a loss of E2 regulation of ADAM 10, ADAM 17, and BACE 1 levels in the hippocampal CA I of LTED females, which provides mechanistic evidence for the enhanced post-ischemic Aβ load following LTED. We also observed loss of E2 regulation of tau hyperphosphorylation in LTED females subjected to GCI. Conclusion： Collectively, these studies partially explain the enhanced risk of dementia and mortality from neurological disorders seen in prematurely menopausal women and support timely initiation of E2 therapy to yield maximum neurological benefit.
