Grain growth of nanostructured Al6061produced by cryorolling and aging process was investigated during isothermalheat treatment in100?500°C temperature range.Transmission electron microscopy(TEM)observations demo...Grain growth of nanostructured Al6061produced by cryorolling and aging process was investigated during isothermalheat treatment in100?500°C temperature range.Transmission electron microscopy(TEM)observations demonstrate that aftercryorolling and aging at130°C for30h,the microstructure contains61nm grains with dispersed50?150nm precipitates and0.248%lattice strain.In addition,an increase in tensile strength up to362MPa because of formation of fine strengtheningprecipitation and nano-sized grains was observed.Thermal stability investigation within100?500°C temperature range showedrelease of lattice strain,dissolution of precipitates and grain growth.According to the X-ray diffraction(XRD)analysis,Mg2Siprecipitates disappeared after annealing at temperatures higher than300°C.According to the results,due to the limited grain growthup to200°C,there would be little decrease in mechanical properties,but within300?500°C range,the grain growth,dissolution ofstrengthening precipitates and decrease in mechanical properties are remarkable.The activation energies for grain growth werecalculated to be203.3kJ/mol for annealing at100?200°C and166.34kJ/mol for annealing at300?500°C.The effect ofprecipitation dissolution on Al lattice parameter,displacement of Al6061(111)XRD peak and Portevin?LeChatelier(PLC)effect onstress?strain curves is also discussed.展开更多
Polycomb group genes play crucial roles in the maintenance of the transcriptionally silenced state of genes for proper cell differentiation in animals and plants. While components of the polycomb repressive complex2 ...Polycomb group genes play crucial roles in the maintenance of the transcriptionally silenced state of genes for proper cell differentiation in animals and plants. While components of the polycomb repressive complex2 （PRC2） are evolutionarily conserved and their functions are extensively studied in plants, PRCI differs considerably between animals and plants, and its functions in plants are as yet not well described. Previous studies have identified the Arabidopsis AtRINGla and AtRINGlb as homologues of the animal PRC1 subunit RING1. Here, we show that the Atringla Atringlb double mutant exhibits derepression of embryonic traits during vegetative growth. Accordingly, several key regulatory genes involved in embryogenesis and stem cell activity are ectopically expressed in the mutant. Furthermore, we show that the mutant phenotypes and increased expression of regulatory genes are enhanced by the PRC2 mutant c/f. Finally, we show that three homologues of the animal PRCl-subunit ring-finger protein BMI1, AtBMIIa, AtBMIlb and AtBMIlc, can bind with AtRINGla or AtRINGIb, and in addition, AtBMIlc can bind with LHP1. The Atbmila Atbmilb double mutant shows derepression of embryonic traits similar to that of the Atringla Atringlb double mutant. Interestingly, expression levels of AtBMIla, AtBMIlb and AtBMIlc are elevated in the Atringla Atringlb mutant and those of AtBMIlc, AtRINGla and AtRINGlb are elevated in the Atbmila Atbmilb mu- tant, suggesting a self-regulatory feedback mechanism. Taken together, our results illuminate crucial functions of the PRCl-like ring-finger components in stable repression of embryonic traits and regulatory genes for proper somatic growth.展开更多
Objective： Flupirtine is a non-opioid analgesic without antipyretic or antiphlogistic properties but with favorable tolerability in humans. ＂Ibis analgesic also exhibits neuroprotective activities. Furthermore, flup...Objective： Flupirtine is a non-opioid analgesic without antipyretic or antiphlogistic properties but with favorable tolerability in humans. ＂Ibis analgesic also exhibits neuroprotective activities. Furthermore, flupirtine antagonizes glutamate- and . , 2＋ NMDA-mduced mtracellular levels of Ca and counteracts the effects of focal cerebral Lscherma. Although fluplrtme has been used to relieve pain caused by different diseases and clinical procedures, information on the safety and efficacy of flupirtine is limited. ＂fhe present study was conducted to investigate the neuroprotective effects of flupirtine on U373 malignant glioma （MG） cell lines. Methods： Cellviability and cell cycle analysis was performed by MTF assay and flow cytomet-,＇y, respectively. Results： Variations in the growth of U373 MG cells in $ mM N-methyl-D-aspartate （NMDA）, 1 mM flupirtine, and combined treatment indicated the antagonistic effects of NMDA and flupirtine on MG cell lines. The variation in the percentage of gated cellpopulation in different cell cycle phases showed significant variations after 48 h of treatment. Conclusion： Flupirtine has neuroprotective effect of on U373 MG cells, which limits its use in the pain management of brain tumors. This property warrants further studies using animal models and large-scale clinical trials.展开更多
Spatial distributions and seasonal variations of picoplankton (i.e. Synechococcus spp., Prochlorococcus spp., picoeukaryotes and heterotrophic bacteria) and viruses in the Changjiang estuary have been reported in the ...Spatial distributions and seasonal variations of picoplankton (i.e. Synechococcus spp., Prochlorococcus spp., picoeukaryotes and heterotrophic bacteria) and viruses in the Changjiang estuary have been reported in the past. However, short-term variations (e.g. at a tidal timescale) of these organisms and their regulating factors remain unclear. We determined the time-series of fluctuations of picoplankton and viruses with tide simultaneously in flow cytometry in the Changjiang estuary during a cruise in June 2006, in which a tidal model based rectangle equation was applied. The results indicate that high cell abundances of picoplankton and viruses occurred during flood tide and low cell abundances during ebb tide. The period of the surface cell abundance variations was about 13 h, suggesting the surface cell abundances in the Changjiang estuary were largely regulated by tide. However, cell abundances in middle and bottom waters varied in different periods due to influences of tidal induced physical forces such as resuspension and stratification. Therefore, tidal action is an important factor for the diel variations of picoplankton and viruses in the Changjiang estuary.展开更多
PROTEUS syndrome is characterized by patchy and progressive overgrowth affecting multiple tissues, including bone, soft tissue, and skin, along with susceptibility to the development oftumors. It was originally descri...PROTEUS syndrome is characterized by patchy and progressive overgrowth affecting multiple tissues, including bone, soft tissue, and skin, along with susceptibility to the development oftumors. It was originally described by Cohen and Hayden in 19791 and named by Wiedmann in 1983.2 The cause of Proteus syndrome is proposed to be a somatic mutation that is lethal in non-mosaic state; cells derived from the mutated cell line carrying this mutation result in anomalies in multiple tissues.3 The clinical manifestations are variable,展开更多
Asthma is a chronic disease of airway inflammation due to excessive T helper cell type 2 （Th2） response. Present treatment based on inhalation of synthetic glucocorticoids can only control Th2-driven chronic eosinop...Asthma is a chronic disease of airway inflammation due to excessive T helper cell type 2 （Th2） response. Present treatment based on inhalation of synthetic glucocorticoids can only control Th2-driven chronic eosinophilic inflammation, but cannot change the immune tolerance of the body to external allergens. Regulatory T cells （Tregs） are the main negative regulatory cells of the immune response. Tregs play a great role in regulating allergic, auto- immune, graft-versus-host responses, and other immune responses. In this review, we will discuss the classification and biological characteristics, the established immunomodulatory mechanisms, and the characteristics of induced differentiation of Tregs. We will also discuss the progress of TregS in the field of asthma. We believe that further studies on the regulatory mechanisms of Tregs will provide better treatments and control strategies for asthma.展开更多
In this paper,we study a long-range percolation model on the lattice Z d with multi-type vertices and directed edges.Each vertex x ∈ Z d is independently assigned a non-negative weight Wx and a type ψx,where(Wx) x∈...In this paper,we study a long-range percolation model on the lattice Z d with multi-type vertices and directed edges.Each vertex x ∈ Z d is independently assigned a non-negative weight Wx and a type ψx,where(Wx) x∈Z d are i.i.d.random variables,and(ψx) x∈Z d are also i.i.d.Conditionally on weights and types,and given λ,α > 0,the edges are independent and the probability that there is a directed edge from x to y is given by pxy = 1 exp(λφψ x ψ y WxWy /| x-y | α),where φij 's are entries from a type matrix Φ.We show that,when the tail of the distribution of Wx is regularly varying with exponent τ-1,the tails of the out/in-degree distributions are both regularly varying with exponent γ = α(τ-1) /d.We formulate conditions under which there exist critical values λ WCC c ∈(0,∞) and λ SCC c ∈(0,∞) such that an infinite weak component and an infinite strong component emerge,respectively,when λ exceeds them.A phase transition is established for the shortest path lengths of directed and undirected edges in the infinite component at the point γ = 2,where the out/in-degrees switch from having finite to infinite variances.The random graph model studied here features some structures of multi-type vertices and directed edges which appear naturally in many real-world networks,such as the SNS networks and computer communication networks.展开更多
文摘Grain growth of nanostructured Al6061produced by cryorolling and aging process was investigated during isothermalheat treatment in100?500°C temperature range.Transmission electron microscopy(TEM)observations demonstrate that aftercryorolling and aging at130°C for30h,the microstructure contains61nm grains with dispersed50?150nm precipitates and0.248%lattice strain.In addition,an increase in tensile strength up to362MPa because of formation of fine strengtheningprecipitation and nano-sized grains was observed.Thermal stability investigation within100?500°C temperature range showedrelease of lattice strain,dissolution of precipitates and grain growth.According to the X-ray diffraction(XRD)analysis,Mg2Siprecipitates disappeared after annealing at temperatures higher than300°C.According to the results,due to the limited grain growthup to200°C,there would be little decrease in mechanical properties,but within300?500°C range,the grain growth,dissolution ofstrengthening precipitates and decrease in mechanical properties are remarkable.The activation energies for grain growth werecalculated to be203.3kJ/mol for annealing at100?200°C and166.34kJ/mol for annealing at300?500°C.The effect ofprecipitation dissolution on Al lattice parameter,displacement of Al6061(111)XRD peak and Portevin?LeChatelier(PLC)effect onstress?strain curves is also discussed.
文摘Polycomb group genes play crucial roles in the maintenance of the transcriptionally silenced state of genes for proper cell differentiation in animals and plants. While components of the polycomb repressive complex2 （PRC2） are evolutionarily conserved and their functions are extensively studied in plants, PRCI differs considerably between animals and plants, and its functions in plants are as yet not well described. Previous studies have identified the Arabidopsis AtRINGla and AtRINGlb as homologues of the animal PRC1 subunit RING1. Here, we show that the Atringla Atringlb double mutant exhibits derepression of embryonic traits during vegetative growth. Accordingly, several key regulatory genes involved in embryogenesis and stem cell activity are ectopically expressed in the mutant. Furthermore, we show that the mutant phenotypes and increased expression of regulatory genes are enhanced by the PRC2 mutant c/f. Finally, we show that three homologues of the animal PRCl-subunit ring-finger protein BMI1, AtBMIIa, AtBMIlb and AtBMIlc, can bind with AtRINGla or AtRINGIb, and in addition, AtBMIlc can bind with LHP1. The Atbmila Atbmilb double mutant shows derepression of embryonic traits similar to that of the Atringla Atringlb double mutant. Interestingly, expression levels of AtBMIla, AtBMIlb and AtBMIlc are elevated in the Atringla Atringlb mutant and those of AtBMIlc, AtRINGla and AtRINGlb are elevated in the Atbmila Atbmilb mu- tant, suggesting a self-regulatory feedback mechanism. Taken together, our results illuminate crucial functions of the PRCl-like ring-finger components in stable repression of embryonic traits and regulatory genes for proper somatic growth.
基金supported by an intramural grant from Sri Ramachandra University,Chennai
文摘Objective： Flupirtine is a non-opioid analgesic without antipyretic or antiphlogistic properties but with favorable tolerability in humans. ＂Ibis analgesic also exhibits neuroprotective activities. Furthermore, flupirtine antagonizes glutamate- and . , 2＋ NMDA-mduced mtracellular levels of Ca and counteracts the effects of focal cerebral Lscherma. Although fluplrtme has been used to relieve pain caused by different diseases and clinical procedures, information on the safety and efficacy of flupirtine is limited. ＂fhe present study was conducted to investigate the neuroprotective effects of flupirtine on U373 malignant glioma （MG） cell lines. Methods： Cellviability and cell cycle analysis was performed by MTF assay and flow cytomet-,＇y, respectively. Results： Variations in the growth of U373 MG cells in $ mM N-methyl-D-aspartate （NMDA）, 1 mM flupirtine, and combined treatment indicated the antagonistic effects of NMDA and flupirtine on MG cell lines. The variation in the percentage of gated cellpopulation in different cell cycle phases showed significant variations after 48 h of treatment. Conclusion： Flupirtine has neuroprotective effect of on U373 MG cells, which limits its use in the pain management of brain tumors. This property warrants further studies using animal models and large-scale clinical trials.
基金Supported by the National Basic Research Program of China (973 Program) (Nos. 2002CB412405, 2004CB720505)a fund to the Innovative Research Team, the Ministry of Education of China (No.IRT0427)+1 种基金the PhD Program Scholarship Fund of ECNU 2007the Special Research Fund for the National Non-profit Institutes (East China Sea Fisheries Research Institutes) (No. 2008M13)
文摘Spatial distributions and seasonal variations of picoplankton (i.e. Synechococcus spp., Prochlorococcus spp., picoeukaryotes and heterotrophic bacteria) and viruses in the Changjiang estuary have been reported in the past. However, short-term variations (e.g. at a tidal timescale) of these organisms and their regulating factors remain unclear. We determined the time-series of fluctuations of picoplankton and viruses with tide simultaneously in flow cytometry in the Changjiang estuary during a cruise in June 2006, in which a tidal model based rectangle equation was applied. The results indicate that high cell abundances of picoplankton and viruses occurred during flood tide and low cell abundances during ebb tide. The period of the surface cell abundance variations was about 13 h, suggesting the surface cell abundances in the Changjiang estuary were largely regulated by tide. However, cell abundances in middle and bottom waters varied in different periods due to influences of tidal induced physical forces such as resuspension and stratification. Therefore, tidal action is an important factor for the diel variations of picoplankton and viruses in the Changjiang estuary.
文摘PROTEUS syndrome is characterized by patchy and progressive overgrowth affecting multiple tissues, including bone, soft tissue, and skin, along with susceptibility to the development oftumors. It was originally described by Cohen and Hayden in 19791 and named by Wiedmann in 1983.2 The cause of Proteus syndrome is proposed to be a somatic mutation that is lethal in non-mosaic state; cells derived from the mutated cell line carrying this mutation result in anomalies in multiple tissues.3 The clinical manifestations are variable,
基金Zhejiang University and Springer-Vedag GmbH Germany, part of Springer Nature 2018
文摘Asthma is a chronic disease of airway inflammation due to excessive T helper cell type 2 （Th2） response. Present treatment based on inhalation of synthetic glucocorticoids can only control Th2-driven chronic eosinophilic inflammation, but cannot change the immune tolerance of the body to external allergens. Regulatory T cells （Tregs） are the main negative regulatory cells of the immune response. Tregs play a great role in regulating allergic, auto- immune, graft-versus-host responses, and other immune responses. In this review, we will discuss the classification and biological characteristics, the established immunomodulatory mechanisms, and the characteristics of induced differentiation of Tregs. We will also discuss the progress of TregS in the field of asthma. We believe that further studies on the regulatory mechanisms of Tregs will provide better treatments and control strategies for asthma.
文摘In this paper,we study a long-range percolation model on the lattice Z d with multi-type vertices and directed edges.Each vertex x ∈ Z d is independently assigned a non-negative weight Wx and a type ψx,where(Wx) x∈Z d are i.i.d.random variables,and(ψx) x∈Z d are also i.i.d.Conditionally on weights and types,and given λ,α > 0,the edges are independent and the probability that there is a directed edge from x to y is given by pxy = 1 exp(λφψ x ψ y WxWy /| x-y | α),where φij 's are entries from a type matrix Φ.We show that,when the tail of the distribution of Wx is regularly varying with exponent τ-1,the tails of the out/in-degree distributions are both regularly varying with exponent γ = α(τ-1) /d.We formulate conditions under which there exist critical values λ WCC c ∈(0,∞) and λ SCC c ∈(0,∞) such that an infinite weak component and an infinite strong component emerge,respectively,when λ exceeds them.A phase transition is established for the shortest path lengths of directed and undirected edges in the infinite component at the point γ = 2,where the out/in-degrees switch from having finite to infinite variances.The random graph model studied here features some structures of multi-type vertices and directed edges which appear naturally in many real-world networks,such as the SNS networks and computer communication networks.
