Guided bone regeneration (GBR) often utilizes a combination of autologous bone grafts, deproteinized bovine bone mineral(DBBM), and collagen membranes. DBBM and collagen membranes pre-coated with bone-conditioned medi...Guided bone regeneration (GBR) often utilizes a combination of autologous bone grafts, deproteinized bovine bone mineral(DBBM), and collagen membranes. DBBM and collagen membranes pre-coated with bone-conditioned medium (BCM) extracted from locally harvested autologous bone chips have shown great regenerative potential in GBR. However, the underlying molecular mechanism remains largely unknown. Here, we investigated the composition of BCM and its activity on the osteogenic potential of mesenchymal stromal cells. We detected a fast and significant (P <0.001) release of transforming growth factor-β1 (TGF-β1) from autologous bone within 10 min versus a delayed bone morphogenetic protein-2 (BMP-2) release from 40 min onwards. BCMs harvested within short time periods (10, 20, or 40 min), corresponding to the time of a typical surgical procedure, significantly increased the proliferative activity and collagen matrix production of BCM-treated cells. Long-term (1, 3, or 6 days)-extracted BCMs promoted the later stages of osteoblast differentiation and maturation. Short-term-extracted BCMs, in which TGF-β1 but no BMP-2was detected, reduced the expression of the late differentiation marker osteocalcin. However, when both growth factors were present simultaneously in the BCM, no inhibitory effects on osteoblast differentiation were observed, suggesting a synergistic TGF-β1/BMP-2 activity. Consequently, in cells that were co-stimulated with recombinant TGF-β1 and BMP-2, we showed a significant stimulatory and dose-dependent effect of TGF-β1 on BMP-2-induced osteoblast differentiation due to prolonged BMP signaling and reduced expression of the BMP-2 antagonist noggin. Altogether, our data provide new insights into the molecular mechanisms underlying the favorable outcome from GBR procedures using BCM, derived from autologous bone grafts.展开更多
Animals must strike a balance between anti-predation behavior and other essential behaviors,such as foraging.Within the same species,strategies may vary on individuals’risk-taking preferences,and in this process the ...Animals must strike a balance between anti-predation behavior and other essential behaviors,such as foraging.Within the same species,strategies may vary on individuals’risk-taking preferences,and in this process the environment is a determinant,in addition to predator regime.The Crested Ibis(Nipponia nippon)exhibits such tendency.This is an endangered species,once inhabiting exclusively in China’s Qinling Mountain.This used to be the sole remaining wild population.However,over recent decades,this population has expanded.A portion has relocated to breed in the lower plain area,which is characterized by elevated level of human activities and landscape complexity.We used flight initiation distance(FID)as an indicator of the ibises’risk-taking preference,particularly their response to human proximity.Additionally,we examined the environmental factors influencing their foraging site selection,including altitude,terrain openness,human activity intensity and human construction.Our findings revealed a significantly shorter FID among individuals relocating to plain habitats,indicating a higher tolerance of human proximity.The results showed that FID decreased with distance to the nearest human settlement.Another finding is that FID was independent of instant human activity intensity and environmental factors(altitude and terrain openness).These different may arise from various combinations of human activity,predation risk,and food abundance within the two habitats.These results provide insights into the in situ conservation of the threatened species within the context of global urbanization.展开更多
A key control point in gene expression is the initiation of protein translation, with a universal stress response being constituted by in- hibitory phosphoryiation of the eukaryotic initiation factor 2α （el F2oL）. ...A key control point in gene expression is the initiation of protein translation, with a universal stress response being constituted by in- hibitory phosphoryiation of the eukaryotic initiation factor 2α （el F2oL）. In humans, four kinases sense diverse physiological stresses to regulate elF2α to control cell differentiation, adaptation, and survival. Here we develop a computational molecular model of elF2α and one of its kinases, the protein kinase R, to simulate the dynamics of their interaction. Predictions generated by coarse-grained dynamics simulations suggest a novel mode of action. Experimentation substantiates these predictions, identifying a previously unrecognized interface in the protein complex, which is constituted by dynamic residues in both elF2α and its kinases that are crucial to regulate protein translation. These findings call for a reinterpretation of the current mechanism of action of the el F2α kinases and demonstrate the value of conducting computational analysis to evaluate protein function.展开更多
In this review article,we pay primary attention to innovative works in the Madden–Julian Oscillation(MJO)field done by Chinese scientists.The historical aspect of discovery of the MJO and earlier studies of its dynam...In this review article,we pay primary attention to innovative works in the Madden–Julian Oscillation(MJO)field done by Chinese scientists.The historical aspect of discovery of the MJO and earlier studies of its dynamics by Chinese scientists are first described.It is followed by the description of recent advances in MJO propagation and initiation dynamics.For MJO eastward propagation,two types of the moisture mode theory are introduced.The first one emphasizes the effect of zonal asymmetry of perturbation moisture in the atmospheric boundary layer and the second one emphasizes the zonal asymmetry of column integrated moisture static energy(MSE)tendency.The mechanisms for MJO initiation over the western Indian Ocean include three distinctive processes:lower tropospheric moistening due to horizontal advection caused by preceding suppressed-phase MJO,midlatitude Rossby wave activity flux convergence in the upper troposphere originated from the Southern Hemisphere,and a delayed sea surface temperature feedback in association with a preceding opposite-phase MJO.The impacts of MJO on low-frequency variability of precipitation and temperature and associated extreme events in East Asia are also discussed.展开更多
A common strategy for improving health behaviors is to emphasize the benefits and reduce the barriers to behavior change. This study investigated potential differences in perceived benefits and barriers related to par...A common strategy for improving health behaviors is to emphasize the benefits and reduce the barriers to behavior change. This study investigated potential differences in perceived benefits and barriers related to participation in physical activity (PA) between women in pre-maintenance versus the maintenance phase of PA behavior to determine if perceived benefits were greater and perceived barriers lower in women with more extensive and successful PA participation experience. Data were collected from a community-based sample (N = 113) of middle-aged African-American women. The sample was stratified into two groups according to how long they had been regularly engaging in PA (6 months or longer versus less than 6 months). Chi-square analyses were conducted to investigate possible differences between the two groups of women in regard to perceived benefits and barriers associated with PA. Descriptive data showed that nearly all of the benefits and barriers to PA were perceived as being important for a majority of the participants and chi-square and t-test results indicated few significant between-group differences (p < .05) in regard to these perceptions. Additional analyses indicated there was no significant between-group difference (p < .05) for Body Mass Index. The results suggest the benefits and barriers related to PA behavior are already valued and understood by many African-American women. Further, the results do not support the commonly held belief that effective health behavior improvement programming should emphasize the benefits and reduce the barriers related to the behavior. Practitioners should consider focusing on other evidenced based factors proven to promote PA behavior such as counseling regarding social support (e.g., buddy system) and increasing self-efficacy (e.g., goal setting) to initiate and sustain a physically active lifestyle.展开更多
基金supported by a grant from the ITI International Team for Implantology Foundation 1235_2017 to M.B.A
文摘Guided bone regeneration (GBR) often utilizes a combination of autologous bone grafts, deproteinized bovine bone mineral(DBBM), and collagen membranes. DBBM and collagen membranes pre-coated with bone-conditioned medium (BCM) extracted from locally harvested autologous bone chips have shown great regenerative potential in GBR. However, the underlying molecular mechanism remains largely unknown. Here, we investigated the composition of BCM and its activity on the osteogenic potential of mesenchymal stromal cells. We detected a fast and significant (P <0.001) release of transforming growth factor-β1 (TGF-β1) from autologous bone within 10 min versus a delayed bone morphogenetic protein-2 (BMP-2) release from 40 min onwards. BCMs harvested within short time periods (10, 20, or 40 min), corresponding to the time of a typical surgical procedure, significantly increased the proliferative activity and collagen matrix production of BCM-treated cells. Long-term (1, 3, or 6 days)-extracted BCMs promoted the later stages of osteoblast differentiation and maturation. Short-term-extracted BCMs, in which TGF-β1 but no BMP-2was detected, reduced the expression of the late differentiation marker osteocalcin. However, when both growth factors were present simultaneously in the BCM, no inhibitory effects on osteoblast differentiation were observed, suggesting a synergistic TGF-β1/BMP-2 activity. Consequently, in cells that were co-stimulated with recombinant TGF-β1 and BMP-2, we showed a significant stimulatory and dose-dependent effect of TGF-β1 on BMP-2-induced osteoblast differentiation due to prolonged BMP signaling and reduced expression of the BMP-2 antagonist noggin. Altogether, our data provide new insights into the molecular mechanisms underlying the favorable outcome from GBR procedures using BCM, derived from autologous bone grafts.
基金supported by National Natural Science Foundation of China(No.32270554 to CD)。
文摘Animals must strike a balance between anti-predation behavior and other essential behaviors,such as foraging.Within the same species,strategies may vary on individuals’risk-taking preferences,and in this process the environment is a determinant,in addition to predator regime.The Crested Ibis(Nipponia nippon)exhibits such tendency.This is an endangered species,once inhabiting exclusively in China’s Qinling Mountain.This used to be the sole remaining wild population.However,over recent decades,this population has expanded.A portion has relocated to breed in the lower plain area,which is characterized by elevated level of human activities and landscape complexity.We used flight initiation distance(FID)as an indicator of the ibises’risk-taking preference,particularly their response to human proximity.Additionally,we examined the environmental factors influencing their foraging site selection,including altitude,terrain openness,human activity intensity and human construction.Our findings revealed a significantly shorter FID among individuals relocating to plain habitats,indicating a higher tolerance of human proximity.The results showed that FID decreased with distance to the nearest human settlement.Another finding is that FID was independent of instant human activity intensity and environmental factors(altitude and terrain openness).These different may arise from various combinations of human activity,predation risk,and food abundance within the two habitats.These results provide insights into the in situ conservation of the threatened species within the context of global urbanization.
文摘A key control point in gene expression is the initiation of protein translation, with a universal stress response being constituted by in- hibitory phosphoryiation of the eukaryotic initiation factor 2α （el F2oL）. In humans, four kinases sense diverse physiological stresses to regulate elF2α to control cell differentiation, adaptation, and survival. Here we develop a computational molecular model of elF2α and one of its kinases, the protein kinase R, to simulate the dynamics of their interaction. Predictions generated by coarse-grained dynamics simulations suggest a novel mode of action. Experimentation substantiates these predictions, identifying a previously unrecognized interface in the protein complex, which is constituted by dynamic residues in both elF2α and its kinases that are crucial to regulate protein translation. These findings call for a reinterpretation of the current mechanism of action of the el F2α kinases and demonstrate the value of conducting computational analysis to evaluate protein function.
基金Supported by the National Key Research and Development Program of China(2018YFC1505804)National Natural Science Foundation of China(41875069,41575043,41575052,41922035,41520104,and 41575062)+1 种基金US NSF AGS-1643297NOAA NA18OAR4310298.
文摘In this review article,we pay primary attention to innovative works in the Madden–Julian Oscillation(MJO)field done by Chinese scientists.The historical aspect of discovery of the MJO and earlier studies of its dynamics by Chinese scientists are first described.It is followed by the description of recent advances in MJO propagation and initiation dynamics.For MJO eastward propagation,two types of the moisture mode theory are introduced.The first one emphasizes the effect of zonal asymmetry of perturbation moisture in the atmospheric boundary layer and the second one emphasizes the zonal asymmetry of column integrated moisture static energy(MSE)tendency.The mechanisms for MJO initiation over the western Indian Ocean include three distinctive processes:lower tropospheric moistening due to horizontal advection caused by preceding suppressed-phase MJO,midlatitude Rossby wave activity flux convergence in the upper troposphere originated from the Southern Hemisphere,and a delayed sea surface temperature feedback in association with a preceding opposite-phase MJO.The impacts of MJO on low-frequency variability of precipitation and temperature and associated extreme events in East Asia are also discussed.
文摘A common strategy for improving health behaviors is to emphasize the benefits and reduce the barriers to behavior change. This study investigated potential differences in perceived benefits and barriers related to participation in physical activity (PA) between women in pre-maintenance versus the maintenance phase of PA behavior to determine if perceived benefits were greater and perceived barriers lower in women with more extensive and successful PA participation experience. Data were collected from a community-based sample (N = 113) of middle-aged African-American women. The sample was stratified into two groups according to how long they had been regularly engaging in PA (6 months or longer versus less than 6 months). Chi-square analyses were conducted to investigate possible differences between the two groups of women in regard to perceived benefits and barriers associated with PA. Descriptive data showed that nearly all of the benefits and barriers to PA were perceived as being important for a majority of the participants and chi-square and t-test results indicated few significant between-group differences (p < .05) in regard to these perceptions. Additional analyses indicated there was no significant between-group difference (p < .05) for Body Mass Index. The results suggest the benefits and barriers related to PA behavior are already valued and understood by many African-American women. Further, the results do not support the commonly held belief that effective health behavior improvement programming should emphasize the benefits and reduce the barriers related to the behavior. Practitioners should consider focusing on other evidenced based factors proven to promote PA behavior such as counseling regarding social support (e.g., buddy system) and increasing self-efficacy (e.g., goal setting) to initiate and sustain a physically active lifestyle.
