The long-term trend of diurnal temperature range(DTR)over Nigeria was examined using daily station-based datasets for the period 1971–2013.The results show that the regionally averaged DTR has decreased significantly...The long-term trend of diurnal temperature range(DTR)over Nigeria was examined using daily station-based datasets for the period 1971–2013.The results show that the regionally averaged DTR has decreased significantly(-0.34°C per decade)over the Nigerian Sahel(north of 10°N),but there has been a slight increasing trend(0.01°C per decade)over the Nigerian Guinea Coast.The annual decreasing trend of DTR in the Nigerian Sahel is mainly attributable to the significant increasing trend in daily minimum temperature(Tmin,0.51°C per decade),which far outstrips the rate of increase in the daily maximum(Tmax,0.17°C per decade).In contrast,the comparable trends in Tmin(0.19°C per decade)and Tmax(0.20°C per decade)may explain the non-significant trend of the DTR averaged over the Guinea Coast region.It is observed that the DTR has decreased more in boreal summer(June–July–August)than in boreal winter(December–January–February)for the regions.Furthermore,it is found that the significant DTR declining trend over the Nigerian Sahel is closely associated with an increasing trend of annual and summer precipitation in the region,but the increasing DTR trend in the Nigerian Guinea Coast region can be attributed to the decreasing trend of cloud cover over the region.展开更多
This study investigates the major patterns of large-scale tilted ridges(LSTRS)over the Eurasian continent and their connections with large-scale surface air temperature during boreal winter.A total number of 134 LSTR ...This study investigates the major patterns of large-scale tilted ridges(LSTRS)over the Eurasian continent and their connections with large-scale surface air temperature during boreal winter.A total number of 134 LSTR events with zonal extent exceeding 90°of longitude on the peak day are identified.Using self-organizing map(SOM),the LSTRs are classified into five clusters that are characterized by different spatial distributions and orientations.The leading two clusters are closely associated with extensive and persistent cold events over different places.Considering the first cluster,LSTRs extend from the Ural Mountains to Northeast Asia and are favorable for the amplification and southeastward extension of the Siberian high.Therefore,this cluster is closely associated with the occurrence of extensive and persistent cold events in china.In comparison with the first cluster,the LSTRs of second group are situated to the west,with starting points from the Kola Peninsula,and cause extensive and persistent cold events over Eastern Europe,central Asia,and central Siberia.The results suggest that the vertical coupling between LSTRs and the corresponding anomalous sea level pressure is crucial for the persistent cold temperature events associated with the leading two SOM clusters.展开更多
Trumpet shell, Charonia sauliae, is an endangered and valuable species, but its artificial propagation protocol has not been successfully established. To estimate the possibility of cryopreservation for larvae of C. s...Trumpet shell, Charonia sauliae, is an endangered and valuable species, but its artificial propagation protocol has not been successfully established. To estimate the possibility of cryopreservation for larvae of C. sauliae, which is a potential preparation for its artificial reproduction and further research, in this study a protocoi for the cryopreservation of veliger larvae of trumpet shell was optimized. Through a two-step cryopreservation procedure, four kinds of cryoprotectants （ethylene glycol, 1, 2-propanediol, dimethyl sulfoxide and glycerol） were employed at three concentrations （1.0, 1.5 and 2.0molL^-1） respectively and survival rates of larvae were determined after a storage of lh. The larvae frozen with these four cryoprotectants after 1 h storage were cultured, and then survival rates were determined at 24, 72 and 120 h after thawing. Dimethyl sulfoxide at a concentration of 1.5 molL^-1 showed the best protective effect in all experiments （p〈0.05）. And survival rates of larvae frozen with dimethyl sulfoxide were determined after 1, 7 and 15 d of storage. The survival rates of larvae frozen with 1.5 molL^-1 dimethyl sulfoxide after 1 h, 1 d, 7 d and 15 d of storage were 80.77% ±7.51%, 80.34%±11.28%, 83.10%±9.14% and 77.23%±6.22% respectively. No significant differences in survival rates of larvae frozen with dimethyl sulfoxide were observed after various storage periods （p〉0.05）.展开更多
Objective To investigate alterations in the microtubule-associated protein 2 (MAP-2) of neurons in Wistar rats and the effect of nimodipine (Nim), D-2-amino-5-phosphonovaleric acid (D-AP-5) and mild hypothermia on ne...Objective To investigate alterations in the microtubule-associated protein 2 (MAP-2) of neurons in Wistar rats and the effect of nimodipine (Nim), D-2-amino-5-phosphonovaleric acid (D-AP-5) and mild hypothermia on neuronal MAP-2 following fluid percussion injury (FPI).Methods Alterations of MAP-2 in Wistar rat neurons following FPI were measured by a confocal laserscanning microscope using MAP-2 immunofluorescence staining as a MAP-2 indicator.Results MAP-2 immunofluorescence staining was limited to the cell bodies and dendritic compartments of neurons and more intense in dendrites than in cell bodies. The loss of MAP-2 was marked at 3 h posttrauma ( P ＜ 0.01 ), and reached a maximum at 48 h post-trauma. Afterwards, fluorescence recovered partly at 72 h post-trauma. The application of Nim markedly reduced the loss of MAP-2 immunoreectivity within 1 h post-trauma ( P ＜ 0.01 ), and the application of D-AP-5 markedly reduced the loss of MAP-2immunoreactivity within 10 h post-injury ( P ＜ 0.01 ). The application of mild hypothermia decreased the loss of MAP-2 immunoreactivity within 1 h post-injury (P＜ 0.05).Conclusions The partial recovery of fluorescence at 72 h post-trauma indicate that the partial structure of the neuronal microtubules can be repaired by itself. Nim, D-AP-5 and mild hypothermia reduce the degradation of MAP-2 by different mechanisms. The treatment of neuronal cytoskeleton degradation following FPI must employ multiple therapeutic approaches.展开更多
Objective： To observe the protective effect of acupuncture plus mild hypothermia on brain tissues in rats with cerebral ischemia-reperfusion injury （CIRI）, and the influence on protein expression levels of phosphor...Objective： To observe the protective effect of acupuncture plus mild hypothermia on brain tissues in rats with cerebral ischemia-reperfusion injury （CIRI）, and the influence on protein expression levels of phosphorylated Raf-1, MEK-2 and ERK3/2 in the mitogen-activated protein kinase （MAPK）/extracellular regulated protein kinases （ERK） pathway, and to explore the mechanism of acupuncture plus mild hypothermia therapy for the ischemic stroke. Methods： Ninety Sprague-Dawley （SD） rats were randomly divided into a blank control group, a sham operation group, a model group, an acupuncture group, a mild hypothermia group and an acupuncture plus mild hypothermia group, 15 rats in each group. Except the rats in the blank control group, the remaining rats were used to prepare the middle cerebral artery occlusion （MCAO） models according to the modified occlusion method using lines, while only the occlusion lines were inserted without blocking the brain arteries of rats in the sham operation group. When the vital signs of rats were stable, rats in the blank control group did not receive any intervention; rats in the sham operation group and the model group received fastening without treatment; rats in the acupuncture group, the mild hypothermia group, and the acupuncture plus mild hypothermia group were treated with the corresponding therapeutic methods. 72 h later, observed neurologic injury score, evaluated infarction area ratio by 2,3,5-tripheyl tetrazolium chloride （TTC） staining, determined apoptosis by TUNEL assay, and measured the phosphorylated Raf-1, MEK-2 and ERK3/2 protein expression levels in rat ischemic hippocampal tissues by Western blot assay. Results： Compared with the blank control group and the sham operation group, after modeling, the neurologic injury score, infarction area ratio and apoptotic cells were increased, and phosphorylated Raf-1, MEK-2 and ERK：1/2 protein expression levels were significantly increased in the model group; the differences were statistically significant （P〈0.05 or P〈0.01）. Compared with the model group, after acupuncture or mild hypothermia therapy, neurologic injury score and infarction area ratio were decreased; apoptotic cells and phosphowlated Raf-1, MEK-2 and ERK1/2 protein expression levels were significantly decreased; the differences were statistically significant （P〈0.05 or P〈0.01）. Compared with the acupuncture group, neurologic injury score and phosphorylated Raf-1, MEK-2 and ERK3/2 protein expression levels were decreased in the acupuncture plus mild hypothermia group; differences between the groups were statistically significant （P〈0.05 or P〈0.01）. Compared with the mild hypothermia group, phosphorylated Raf-1, MEK-2 and ERK1/2 protein expression levels decreased in the acupuncture plus mild hypothermia group, and differences were statistically significant （P〈0.01）. Conclusion： Acupuncture or mild hypothermia therapy can improve neurologic injury, reduce infarction area and apoptosis, which brought about protective effect on the brain tissues, in the MCAO model. The protective effect of acupuncture plus mild hypothermia group is the strongest. The mechanism may involve the MAPK/ERK pathway, by reducing the phosphorylated Raf-l, MEK-2 and ERK：1/2 protein expression levels.展开更多
In the present study,numerical calculations of the flow-field around the airfoil model are performed by using the OpenFOAM in high subsonic flows.The airfoil model is NACA 64A010.The maximum thickness is 10 % of the c...In the present study,numerical calculations of the flow-field around the airfoil model are performed by using the OpenFOAM in high subsonic flows.The airfoil model is NACA 64A010.The maximum thickness is 10 % of the chord length.The SonicFOAM and the RhoCentralFOAM are selected as the solver in high subsonic flows.The grid point is 158,000 and the Mach numbers are 0.277 and 0.569 respectively.The CFD data are compared with the experimental data performed by the cryogenic wind tunnel in the past.The results are as follows.The numerical results of the pressure coefficient distribution on the model surface calculated by the SonicFOAM solver showed good agreement with the experimental data measured by the cryogenic wind tunnel.And the data calculated by the SonicFOAM have the capability for the quantitative comparison of the experimental data at low angle of attack.展开更多
基金jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)[grant number XDA19030403]the National Natural Science Foundation of China [grant number 41575095]+2 种基金the CAS ‘Belt and Road Initiatives’ Program on International Cooperation [grant number 134111KYSB20160010]Victor Nnamdi DIKE acknowledges support from the CAS–TWAS(The World Academy of Sciences)President FellowshipHyacinth NNAMCHI is supported by the International Federation for Science(W/4849)
文摘The long-term trend of diurnal temperature range(DTR)over Nigeria was examined using daily station-based datasets for the period 1971–2013.The results show that the regionally averaged DTR has decreased significantly(-0.34°C per decade)over the Nigerian Sahel(north of 10°N),but there has been a slight increasing trend(0.01°C per decade)over the Nigerian Guinea Coast.The annual decreasing trend of DTR in the Nigerian Sahel is mainly attributable to the significant increasing trend in daily minimum temperature(Tmin,0.51°C per decade),which far outstrips the rate of increase in the daily maximum(Tmax,0.17°C per decade).In contrast,the comparable trends in Tmin(0.19°C per decade)and Tmax(0.20°C per decade)may explain the non-significant trend of the DTR averaged over the Guinea Coast region.It is observed that the DTR has decreased more in boreal summer(June–July–August)than in boreal winter(December–January–February)for the regions.Furthermore,it is found that the significant DTR declining trend over the Nigerian Sahel is closely associated with an increasing trend of annual and summer precipitation in the region,but the increasing DTR trend in the Nigerian Guinea Coast region can be attributed to the decreasing trend of cloud cover over the region.
基金jointly supported by the National Natural Science Foundation of China [grant number 41375064 and41675086]the National Key Technology Research and Development Program of the Ministry of Science and Technology of China [grant number 2015BAC03B03]
文摘This study investigates the major patterns of large-scale tilted ridges(LSTRS)over the Eurasian continent and their connections with large-scale surface air temperature during boreal winter.A total number of 134 LSTR events with zonal extent exceeding 90°of longitude on the peak day are identified.Using self-organizing map(SOM),the LSTRs are classified into five clusters that are characterized by different spatial distributions and orientations.The leading two clusters are closely associated with extensive and persistent cold events over different places.Considering the first cluster,LSTRs extend from the Ural Mountains to Northeast Asia and are favorable for the amplification and southeastward extension of the Siberian high.Therefore,this cluster is closely associated with the occurrence of extensive and persistent cold events in china.In comparison with the first cluster,the LSTRs of second group are situated to the west,with starting points from the Kola Peninsula,and cause extensive and persistent cold events over Eastern Europe,central Asia,and central Siberia.The results suggest that the vertical coupling between LSTRs and the corresponding anomalous sea level pressure is crucial for the persistent cold temperature events associated with the leading two SOM clusters.
文摘Trumpet shell, Charonia sauliae, is an endangered and valuable species, but its artificial propagation protocol has not been successfully established. To estimate the possibility of cryopreservation for larvae of C. sauliae, which is a potential preparation for its artificial reproduction and further research, in this study a protocoi for the cryopreservation of veliger larvae of trumpet shell was optimized. Through a two-step cryopreservation procedure, four kinds of cryoprotectants （ethylene glycol, 1, 2-propanediol, dimethyl sulfoxide and glycerol） were employed at three concentrations （1.0, 1.5 and 2.0molL^-1） respectively and survival rates of larvae were determined after a storage of lh. The larvae frozen with these four cryoprotectants after 1 h storage were cultured, and then survival rates were determined at 24, 72 and 120 h after thawing. Dimethyl sulfoxide at a concentration of 1.5 molL^-1 showed the best protective effect in all experiments （p〈0.05）. And survival rates of larvae frozen with dimethyl sulfoxide were determined after 1, 7 and 15 d of storage. The survival rates of larvae frozen with 1.5 molL^-1 dimethyl sulfoxide after 1 h, 1 d, 7 d and 15 d of storage were 80.77% ±7.51%, 80.34%±11.28%, 83.10%±9.14% and 77.23%±6.22% respectively. No significant differences in survival rates of larvae frozen with dimethyl sulfoxide were observed after various storage periods （p〉0.05）.
基金ThisstudywassupportedbyagrantfromtheFoundationofHeilongjiangDevelopmentinMedicalSciences (No G98C19 13)
文摘Objective To investigate alterations in the microtubule-associated protein 2 (MAP-2) of neurons in Wistar rats and the effect of nimodipine (Nim), D-2-amino-5-phosphonovaleric acid (D-AP-5) and mild hypothermia on neuronal MAP-2 following fluid percussion injury (FPI).Methods Alterations of MAP-2 in Wistar rat neurons following FPI were measured by a confocal laserscanning microscope using MAP-2 immunofluorescence staining as a MAP-2 indicator.Results MAP-2 immunofluorescence staining was limited to the cell bodies and dendritic compartments of neurons and more intense in dendrites than in cell bodies. The loss of MAP-2 was marked at 3 h posttrauma ( P ＜ 0.01 ), and reached a maximum at 48 h post-trauma. Afterwards, fluorescence recovered partly at 72 h post-trauma. The application of Nim markedly reduced the loss of MAP-2 immunoreectivity within 1 h post-trauma ( P ＜ 0.01 ), and the application of D-AP-5 markedly reduced the loss of MAP-2immunoreactivity within 10 h post-injury ( P ＜ 0.01 ). The application of mild hypothermia decreased the loss of MAP-2 immunoreactivity within 1 h post-injury (P＜ 0.05).Conclusions The partial recovery of fluorescence at 72 h post-trauma indicate that the partial structure of the neuronal microtubules can be repaired by itself. Nim, D-AP-5 and mild hypothermia reduce the degradation of MAP-2 by different mechanisms. The treatment of neuronal cytoskeleton degradation following FPI must employ multiple therapeutic approaches.
基金supported by National Natural Science Foundation of China(No.81303051)Traditional Chinese Medicine Science Research Planning Project of Hunan Province(No.201471)Province and Ministry Co-construction Key Laboratory for Internal Medicine of Traditional Chinese Medicine of the Education Ministry of China(No.ZYNK201501)~~
文摘Objective： To observe the protective effect of acupuncture plus mild hypothermia on brain tissues in rats with cerebral ischemia-reperfusion injury （CIRI）, and the influence on protein expression levels of phosphorylated Raf-1, MEK-2 and ERK3/2 in the mitogen-activated protein kinase （MAPK）/extracellular regulated protein kinases （ERK） pathway, and to explore the mechanism of acupuncture plus mild hypothermia therapy for the ischemic stroke. Methods： Ninety Sprague-Dawley （SD） rats were randomly divided into a blank control group, a sham operation group, a model group, an acupuncture group, a mild hypothermia group and an acupuncture plus mild hypothermia group, 15 rats in each group. Except the rats in the blank control group, the remaining rats were used to prepare the middle cerebral artery occlusion （MCAO） models according to the modified occlusion method using lines, while only the occlusion lines were inserted without blocking the brain arteries of rats in the sham operation group. When the vital signs of rats were stable, rats in the blank control group did not receive any intervention; rats in the sham operation group and the model group received fastening without treatment; rats in the acupuncture group, the mild hypothermia group, and the acupuncture plus mild hypothermia group were treated with the corresponding therapeutic methods. 72 h later, observed neurologic injury score, evaluated infarction area ratio by 2,3,5-tripheyl tetrazolium chloride （TTC） staining, determined apoptosis by TUNEL assay, and measured the phosphorylated Raf-1, MEK-2 and ERK3/2 protein expression levels in rat ischemic hippocampal tissues by Western blot assay. Results： Compared with the blank control group and the sham operation group, after modeling, the neurologic injury score, infarction area ratio and apoptotic cells were increased, and phosphorylated Raf-1, MEK-2 and ERK：1/2 protein expression levels were significantly increased in the model group; the differences were statistically significant （P〈0.05 or P〈0.01）. Compared with the model group, after acupuncture or mild hypothermia therapy, neurologic injury score and infarction area ratio were decreased; apoptotic cells and phosphowlated Raf-1, MEK-2 and ERK1/2 protein expression levels were significantly decreased; the differences were statistically significant （P〈0.05 or P〈0.01）. Compared with the acupuncture group, neurologic injury score and phosphorylated Raf-1, MEK-2 and ERK3/2 protein expression levels were decreased in the acupuncture plus mild hypothermia group; differences between the groups were statistically significant （P〈0.05 or P〈0.01）. Compared with the mild hypothermia group, phosphorylated Raf-1, MEK-2 and ERK1/2 protein expression levels decreased in the acupuncture plus mild hypothermia group, and differences were statistically significant （P〈0.01）. Conclusion： Acupuncture or mild hypothermia therapy can improve neurologic injury, reduce infarction area and apoptosis, which brought about protective effect on the brain tissues, in the MCAO model. The protective effect of acupuncture plus mild hypothermia group is the strongest. The mechanism may involve the MAPK/ERK pathway, by reducing the phosphorylated Raf-l, MEK-2 and ERK：1/2 protein expression levels.
文摘In the present study,numerical calculations of the flow-field around the airfoil model are performed by using the OpenFOAM in high subsonic flows.The airfoil model is NACA 64A010.The maximum thickness is 10 % of the chord length.The SonicFOAM and the RhoCentralFOAM are selected as the solver in high subsonic flows.The grid point is 158,000 and the Mach numbers are 0.277 and 0.569 respectively.The CFD data are compared with the experimental data performed by the cryogenic wind tunnel in the past.The results are as follows.The numerical results of the pressure coefficient distribution on the model surface calculated by the SonicFOAM solver showed good agreement with the experimental data measured by the cryogenic wind tunnel.And the data calculated by the SonicFOAM have the capability for the quantitative comparison of the experimental data at low angle of attack.
