Objective:To explore the protective mechanisms of nerve growth factor (NGF) on spinal cord injury (SCI) and provide theoretical basis for its clinical application. Methods: The SCI of Wistar rats was done by Allens w...Objective:To explore the protective mechanisms of nerve growth factor (NGF) on spinal cord injury (SCI) and provide theoretical basis for its clinical application. Methods: The SCI of Wistar rats was done by Allens weight dropping way by a 10 g×2.5 cm impact on the posterior of spinal cord T 8. NGF (3 g/L, 20 μl) or normal saline was injected through catheter into subarachnoid space 2, 4, 8, 12 and 24 h after SCI. The expression of N-methyl-D-asparate receptor 1 (NMDAR 1) and neuronal constitutive nitric oxide synthase (ncNOS) mRNA in rat spinal cord was detected by in situ hybridization. Results: Abnormal expression of NMDAR 1 and ncNOS mRNA appeared in spinal ventral horn motorneuron in injured rats, as compared with that in control group. The expression of NMDAR 1 and ncNOS mRNA in NGF group was significantly lower than that in saline group (P<0.01). Conclusion: NGF can protect spinal cord against injury in vivo. One of the mechanisms is that NGF can prohibit NMDAR 1 and nitric oxide (NO) production after spinal cord injury.展开更多
Polychaetes provide an excellent food resource for fi sh and represent the dominant zoobenthos in marine ecosystems. Diel variation in the rates of metabolism and ammonia-N excretion of Marphysa sanguinea were studied...Polychaetes provide an excellent food resource for fi sh and represent the dominant zoobenthos in marine ecosystems. Diel variation in the rates of metabolism and ammonia-N excretion of Marphysa sanguinea were studied. The worms were grouped according to their wet body weight into small（S; 1.24±0.06 g）, medium（M; 4.00±0.30 g）, and large（L; 8.54±1.08 g） categories. Their weight-specifi c metabolic rates, based on aerobic respiration（ R）, were measured at 16℃（±0.2℃） and classed as either routine（ RR） or standard（ RS） rates. Both respiration types decreased with increasing body weight. Respiration was described by R = a W^b, where b was-0.400 9 and-0.532 0 for RR and RS, respectively. Diurnal changes in RS for each group was relatively flat, with a slightly increasing trend with time, but was relatively stable as a whole. RR of the diurnal variation of worms was higher than RS, but both had similar overall trends. The peak values of specifi c dynamic action（SDA）（ RSDA） in the S, M, and L groups were 2.704, 1.149, and 0.682 mg/（g·h）, respectively. The durations of SDA were 13, 6, and 6 h, respectively and the energy expenditures of SDA were 377.98, 117.34, and 74.94 J/g, respectively. These data indicate that the metabolic rates were higher in smaller individuals, which is advantageous for their rapid growth.展开更多
The integrated extraction of coal and gas combines coal mining with gas capture. Taking into account the gas deposition and flow conditions in the Chinese coal basins, this paper describes the status of the theory and...The integrated extraction of coal and gas combines coal mining with gas capture. Taking into account the gas deposition and flow conditions in the Chinese coal basins, this paper describes the status of the theory and key technologies of this integrated extraction system, and presents its application and practice in the Shaqu, Zhongxing, Fenghuangshan and Pingmei mines. Areas for further improvements in future studies are discussed, focusing in particular on the fundamentals of the extraction system to make it greener, more scientific, and more advanced in both the exploitation and utilization of coal and the gas in coal.展开更多
Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation re...Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation restoration in the Beijing-Tianjin Sand Source Region(BTSSR) from 2000 to 2010 based on the rain use efficiency(RUE) trend in relation to the land cover. More than half of the BTSSR experienced a vegetation productivity increase from 2000 to 2010, with the increasing intensity being sensitive to the indicators chosen. A clear tendency towards smaller increasing areas was shown when using the net primary productivity(NPP, 51.30%) instead of the accumulated normalized difference vegetation index(59.30%). The short-term variation in the precipitation and intra-seasonal precipitation distribution had a great impact on the remote sensing-based vegetation productivity. However, the residual trends method(RESTREND) effectively eliminated this correlation, while incorporating the variance and skewness of the precipitation distribution increased the models′ ability to explain the vegetation productivity variation. The RUE combined with land cover dynamics was valid for the effectiveness assessment of the ecological engineering projects on vegetation restoration. Particularly, the result based on growing season accumulated normalized difference vegetation index(ΣNDVI) residuals was the most effective, showing that 47.39% of the BTSSR experienced vegetation restoration from 2000 to 2010. The effectiveness of the ecological engineering projects differed for each subarea and was proportional to the strength of ecological engineering. The water erosion region dominated by woodland showed the best restoration, followed by the wind-water erosion crisscross regions, while the wind erosion regions dominated by grassland showed the worst effect. Seriously degraded regions still cover more area in the BTSSR than restored regions. Therefore, more future effort should be put in restoring degraded land.展开更多
A comprehensive first principles study of III-Antimonide binary compounds is hardly found in literature. We report a broad study of structural and electronic properties of boron antimonide （BSb）, aluminium antimoni...A comprehensive first principles study of III-Antimonide binary compounds is hardly found in literature. We report a broad study of structural and electronic properties of boron antimonide （BSb）, aluminium antimonide （AlSb）, gallium antimonide （GaSb） and indium antimonide （InSb） in zineblende phase based on density functional theory （DFT）. Our calculations are based on Full-PotentiM Lineaxized Augmented Plane wave plus local orbitals （FP- L（APWq-lo）） method. Different forms of exchange-correlation energy functional and corresponding potential are employed for structural and electronic properties. Our computed results for lattice parameters, bulk moduli, their pressure derivatives, and cohesive energy are consistent with the available experimental data. Boron antimonide is found to be the hardest compound of this group. For band structure calculations, in addition to LDA and GGA, we used GGA-EV, an approximation employed by Engel and Vosko. The band gap results with GGA-EV are of significant improvement over the earlier work.展开更多
As the development of productive forces, the most critical and most active factors in people is the fimdamental driving force of regional economic sustainable development and cooperation has a vital role in regional e...As the development of productive forces, the most critical and most active factors in people is the fimdamental driving force of regional economic sustainable development and cooperation has a vital role in regional economic development Only speed up regional economic cooperation and enforce the integration of regional talent development, can the Beijing-Tianjin-Hebei region achieves rapid development, and become China＇ s third largest economic growth pole, following the Pearl River Delta and Yangtze River Delta. Based on reviewing the integration process of the integration of regional talent development in the Beijing-Tianjin-Hebci region, this paper further analyze differences in the economic development status, the level of human capital, wage levels, employment status, and the development of educational science and technology among Hebei Province, Beijing and Tianjin, and concludes talent development strategy for Hebei Province replying the personnel integration of Beijing, Tianjin and Hebei Province.展开更多
文摘Objective:To explore the protective mechanisms of nerve growth factor (NGF) on spinal cord injury (SCI) and provide theoretical basis for its clinical application. Methods: The SCI of Wistar rats was done by Allens weight dropping way by a 10 g×2.5 cm impact on the posterior of spinal cord T 8. NGF (3 g/L, 20 μl) or normal saline was injected through catheter into subarachnoid space 2, 4, 8, 12 and 24 h after SCI. The expression of N-methyl-D-asparate receptor 1 (NMDAR 1) and neuronal constitutive nitric oxide synthase (ncNOS) mRNA in rat spinal cord was detected by in situ hybridization. Results: Abnormal expression of NMDAR 1 and ncNOS mRNA appeared in spinal ventral horn motorneuron in injured rats, as compared with that in control group. The expression of NMDAR 1 and ncNOS mRNA in NGF group was significantly lower than that in saline group (P<0.01). Conclusion: NGF can protect spinal cord against injury in vivo. One of the mechanisms is that NGF can prohibit NMDAR 1 and nitric oxide (NO) production after spinal cord injury.
基金Supported by the National Natural Science Foundation of China(No.30901107)the National Marine Public Welfare Research Project(Nos.201305002,201305043)the Project of Marine Ecological Restoration Technology Research to the Penglai 19-3 Oil Spill Accident(No.19-3YJ09)
文摘Polychaetes provide an excellent food resource for fi sh and represent the dominant zoobenthos in marine ecosystems. Diel variation in the rates of metabolism and ammonia-N excretion of Marphysa sanguinea were studied. The worms were grouped according to their wet body weight into small（S; 1.24±0.06 g）, medium（M; 4.00±0.30 g）, and large（L; 8.54±1.08 g） categories. Their weight-specifi c metabolic rates, based on aerobic respiration（ R）, were measured at 16℃（±0.2℃） and classed as either routine（ RR） or standard（ RS） rates. Both respiration types decreased with increasing body weight. Respiration was described by R = a W^b, where b was-0.400 9 and-0.532 0 for RR and RS, respectively. Diurnal changes in RS for each group was relatively flat, with a slightly increasing trend with time, but was relatively stable as a whole. RR of the diurnal variation of worms was higher than RS, but both had similar overall trends. The peak values of specifi c dynamic action（SDA）（ RSDA） in the S, M, and L groups were 2.704, 1.149, and 0.682 mg/（g·h）, respectively. The durations of SDA were 13, 6, and 6 h, respectively and the energy expenditures of SDA were 377.98, 117.34, and 74.94 J/g, respectively. These data indicate that the metabolic rates were higher in smaller individuals, which is advantageous for their rapid growth.
文摘The integrated extraction of coal and gas combines coal mining with gas capture. Taking into account the gas deposition and flow conditions in the Chinese coal basins, this paper describes the status of the theory and key technologies of this integrated extraction system, and presents its application and practice in the Shaqu, Zhongxing, Fenghuangshan and Pingmei mines. Areas for further improvements in future studies are discussed, focusing in particular on the fundamentals of the extraction system to make it greener, more scientific, and more advanced in both the exploitation and utilization of coal and the gas in coal.
基金Under the auspices of National Natural Science Foundation of China(No.41571421)National Science and Technology Major Project of China(No.21-Y30B05-9001-13/15)
文摘Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation restoration in the Beijing-Tianjin Sand Source Region(BTSSR) from 2000 to 2010 based on the rain use efficiency(RUE) trend in relation to the land cover. More than half of the BTSSR experienced a vegetation productivity increase from 2000 to 2010, with the increasing intensity being sensitive to the indicators chosen. A clear tendency towards smaller increasing areas was shown when using the net primary productivity(NPP, 51.30%) instead of the accumulated normalized difference vegetation index(59.30%). The short-term variation in the precipitation and intra-seasonal precipitation distribution had a great impact on the remote sensing-based vegetation productivity. However, the residual trends method(RESTREND) effectively eliminated this correlation, while incorporating the variance and skewness of the precipitation distribution increased the models′ ability to explain the vegetation productivity variation. The RUE combined with land cover dynamics was valid for the effectiveness assessment of the ecological engineering projects on vegetation restoration. Particularly, the result based on growing season accumulated normalized difference vegetation index(ΣNDVI) residuals was the most effective, showing that 47.39% of the BTSSR experienced vegetation restoration from 2000 to 2010. The effectiveness of the ecological engineering projects differed for each subarea and was proportional to the strength of ecological engineering. The water erosion region dominated by woodland showed the best restoration, followed by the wind-water erosion crisscross regions, while the wind erosion regions dominated by grassland showed the worst effect. Seriously degraded regions still cover more area in the BTSSR than restored regions. Therefore, more future effort should be put in restoring degraded land.
文摘A comprehensive first principles study of III-Antimonide binary compounds is hardly found in literature. We report a broad study of structural and electronic properties of boron antimonide （BSb）, aluminium antimonide （AlSb）, gallium antimonide （GaSb） and indium antimonide （InSb） in zineblende phase based on density functional theory （DFT）. Our calculations are based on Full-PotentiM Lineaxized Augmented Plane wave plus local orbitals （FP- L（APWq-lo）） method. Different forms of exchange-correlation energy functional and corresponding potential are employed for structural and electronic properties. Our computed results for lattice parameters, bulk moduli, their pressure derivatives, and cohesive energy are consistent with the available experimental data. Boron antimonide is found to be the hardest compound of this group. For band structure calculations, in addition to LDA and GGA, we used GGA-EV, an approximation employed by Engel and Vosko. The band gap results with GGA-EV are of significant improvement over the earlier work.
文摘As the development of productive forces, the most critical and most active factors in people is the fimdamental driving force of regional economic sustainable development and cooperation has a vital role in regional economic development Only speed up regional economic cooperation and enforce the integration of regional talent development, can the Beijing-Tianjin-Hebei region achieves rapid development, and become China＇ s third largest economic growth pole, following the Pearl River Delta and Yangtze River Delta. Based on reviewing the integration process of the integration of regional talent development in the Beijing-Tianjin-Hebci region, this paper further analyze differences in the economic development status, the level of human capital, wage levels, employment status, and the development of educational science and technology among Hebei Province, Beijing and Tianjin, and concludes talent development strategy for Hebei Province replying the personnel integration of Beijing, Tianjin and Hebei Province.
