目的探讨不同追踪触发监测频率对冠状动脉CTA图像质量及辐射剂量的影响。方法选择2016年1月至2018年12月佛山市禅城区中心医院诊治的144例冠心病患者为研究对象,按随机数表法将其分为A (54例)、B (46例)、C (44例)三组,均接受冠状动脉CT...目的探讨不同追踪触发监测频率对冠状动脉CTA图像质量及辐射剂量的影响。方法选择2016年1月至2018年12月佛山市禅城区中心医院诊治的144例冠心病患者为研究对象,按随机数表法将其分为A (54例)、B (46例)、C (44例)三组,均接受冠状动脉CTA检查,A、B、C三组追踪触发监测频率分别为1.14 s、1.17 s、2.00 s,观察并比较三组冠状动脉CTA图像质量及辐射剂量的差异。结果 A组、B组和C组患者的反折现象比率分别为22.22%、17.39%和6.82%,差异有统计学意义(P<0.05);A组、B组和C组患者主动脉根部(AO)的CT值[(486.23±5.02) Hu vs (464.22±6.57) Hu vs (494.17±5.91) Hu]、噪声[(34.25±5.26) vs (32.11±4.25) vs (33.47±4.23)]、信噪比(SNR)[(14.455±3.20) vs (15.23±2.15) vs (14.28±1.32)]和对比信噪比(CNR)[(23.45±10.23) vs (20.23±8.78) vs (25.47±5.56)]比较差异均无统计学意义(P>0.05);A组、B组和C组患者右冠状动脉近段(RCA)和左主干(LM)中的CT值[(472.44±64.11) Hu vs (455.27±95.21) Hu vs (455.78±62.44) Hu]和CNR [(25.44±7.23) vs (28.47±23.01) vs (28.47±5.26)]以及主观评分[(1.89±0.06)分vs (1.86±0.04)分vs (1.88±0.05)分]等指标比较差异均无统计学意义(P>0.05);A组监测次数为(4.77±2.23)次,高于B组的(3.72±1.44)次和C组的(2.71±0.95)次,而B组又高于C组,差异均有统计学意义(P<0.05);A组、B组和C组患者辐射剂量中的剂量长度乘积(DLP)[(4.10±2.23) mSv vs (2.15±0.82) mSv vs (1.51±0.53) m Sv]和有效剂量(ED)[(0.057±0.031) mSv vs (0.034±0.015) mSv vs (0.023±0.008) mSv]比较,A组均高于B、C两组,B组又高于C组,差异均有统计学意义(P<0.05)。结论不同追踪触发监测频率获得图像质量均较高,但监测频率为2.00 s时能显著降低监测次数及辐射剂量。展开更多
Reducing the threats of sulfate ion(SO42-)deposition to terrestrial ecosystems is a great challenge.The canopy interception effect on SO42-deposition has been well documented,but the interception efficiency of the gap...Reducing the threats of sulfate ion(SO42-)deposition to terrestrial ecosystems is a great challenge.The canopy interception effect on SO42-deposition has been well documented,but the interception efficiency of the gap edge remains unknown.Therefore,a subalpine dragon spruce(Picea asperata)plantation was evaluated in the upper reaches of the Yangtze River.The dynamics of the SO42-concentration in the throughfall were investigated from the gap edge to the closed canopy during the rainfall and snowfall periods from August 2015 to July 2016.The annual input of SO42-totaled 2.56 kg/ha through rainfall and 0.69 kg/ha through snowfall.The total annual net interception fluxes(NIFs)of SO42-at the gap edge and in the closed canopy were 1.48 kg/ha and 0.66 kg/ha,respectively,and the net interception ratios(NIRs)accounted for 45.40%and 20.25%,respectively.The NIF and the NIR of SO42-at the gap edge were higher than those in the closed canopy.Therefore,the results suggested that a significant amount of SO42-deposition was intercepted by the tree canopy in the subalpine plantation,with more SO42-deposition at the gap edge than in the closed canopy,which is beneficial for improving the water quality in the upper reaches of the Yangtze River via forest management.展开更多
As an arthropod biocide,naphthalene has been used in studies of the ecological functions of soil fauna for decades.However,its potential non-target effects on soil microorganisms may affect soil mineralization and lit...As an arthropod biocide,naphthalene has been used in studies of the ecological functions of soil fauna for decades.However,its potential non-target effects on soil microorganisms may affect soil mineralization and litter decomposition processes.Therefore,we conducted an experiment with naphthalene adding to soil surface at a rate of 100 g·m-2 per month to examine the potential non-target effects of this treatment on soil fungal phospholipid fatty acids(PLFAs),18 S rDNA gene copy numbers and community diversity in a subalpine forest of western Sichuan,China.The results showed that naphthalene addition significantly increased fungal PLFAs but did not significantly alter fungal gene copy numbers.A total of 16 phyla,62 genera and 147 Operational taxonomic units(OTUs)were identified through Illumina Mi Seq sequencing analysis.Basidiomycota and Ascomycota were the most abundant phyla in both the control and naphthalene addition plots.Naphthalene addition did not affect the diversity or structure of the soil fungal community,but the increase in some genera of Basidiomycota might contribute to the increase in fungal PLFAs in the naphthalene addition plots.These results suggest that naphthalene exerts non-target effects on the active fungal abundance by stimulating the abundance of specific taxa in subalpine forest soils.The non-target effects of naphthalene on the fungal community should be taken into consideration when it is used to exclude soil fauna.展开更多
A layer of TiO_(x) was deposited on powdery γ-Al_(2)O_(3) by using Sat-target magnetron sputtering in microwave electron cyclotron resonance plasma.A vibrator was developed to coat the γ-Al_(2)O_(3) particles evenly...A layer of TiO_(x) was deposited on powdery γ-Al_(2)O_(3) by using Sat-target magnetron sputtering in microwave electron cyclotron resonance plasma.A vibrator was developed to coat the γ-Al_(2)O_(3) particles evenly by TiO_(x).The conversion efficiency of methane and both the yield and the selectivity of C_(2) hydrocarbons and C_(2)H_(2) were revealed to be superior to that by conventional chemical method.The use of vibrator is effective.展开更多
文摘目的探讨不同追踪触发监测频率对冠状动脉CTA图像质量及辐射剂量的影响。方法选择2016年1月至2018年12月佛山市禅城区中心医院诊治的144例冠心病患者为研究对象,按随机数表法将其分为A (54例)、B (46例)、C (44例)三组,均接受冠状动脉CTA检查,A、B、C三组追踪触发监测频率分别为1.14 s、1.17 s、2.00 s,观察并比较三组冠状动脉CTA图像质量及辐射剂量的差异。结果 A组、B组和C组患者的反折现象比率分别为22.22%、17.39%和6.82%,差异有统计学意义(P<0.05);A组、B组和C组患者主动脉根部(AO)的CT值[(486.23±5.02) Hu vs (464.22±6.57) Hu vs (494.17±5.91) Hu]、噪声[(34.25±5.26) vs (32.11±4.25) vs (33.47±4.23)]、信噪比(SNR)[(14.455±3.20) vs (15.23±2.15) vs (14.28±1.32)]和对比信噪比(CNR)[(23.45±10.23) vs (20.23±8.78) vs (25.47±5.56)]比较差异均无统计学意义(P>0.05);A组、B组和C组患者右冠状动脉近段(RCA)和左主干(LM)中的CT值[(472.44±64.11) Hu vs (455.27±95.21) Hu vs (455.78±62.44) Hu]和CNR [(25.44±7.23) vs (28.47±23.01) vs (28.47±5.26)]以及主观评分[(1.89±0.06)分vs (1.86±0.04)分vs (1.88±0.05)分]等指标比较差异均无统计学意义(P>0.05);A组监测次数为(4.77±2.23)次,高于B组的(3.72±1.44)次和C组的(2.71±0.95)次,而B组又高于C组,差异均有统计学意义(P<0.05);A组、B组和C组患者辐射剂量中的剂量长度乘积(DLP)[(4.10±2.23) mSv vs (2.15±0.82) mSv vs (1.51±0.53) m Sv]和有效剂量(ED)[(0.057±0.031) mSv vs (0.034±0.015) mSv vs (0.023±0.008) mSv]比较,A组均高于B、C两组,B组又高于C组,差异均有统计学意义(P<0.05)。结论不同追踪触发监测频率获得图像质量均较高,但监测频率为2.00 s时能显著降低监测次数及辐射剂量。
基金funded by the National Key R&D Program of China (Grant No. 2017YFC0503906)the Nation Nature Science Foundation of China (Grant Nos. 31570445, 31622018, 31670526 and 31901295)the Sichuan Province and Technology Project for Youth Innovation Team (Grant No. 2017TD0022)
文摘Reducing the threats of sulfate ion(SO42-)deposition to terrestrial ecosystems is a great challenge.The canopy interception effect on SO42-deposition has been well documented,but the interception efficiency of the gap edge remains unknown.Therefore,a subalpine dragon spruce(Picea asperata)plantation was evaluated in the upper reaches of the Yangtze River.The dynamics of the SO42-concentration in the throughfall were investigated from the gap edge to the closed canopy during the rainfall and snowfall periods from August 2015 to July 2016.The annual input of SO42-totaled 2.56 kg/ha through rainfall and 0.69 kg/ha through snowfall.The total annual net interception fluxes(NIFs)of SO42-at the gap edge and in the closed canopy were 1.48 kg/ha and 0.66 kg/ha,respectively,and the net interception ratios(NIRs)accounted for 45.40%and 20.25%,respectively.The NIF and the NIR of SO42-at the gap edge were higher than those in the closed canopy.Therefore,the results suggested that a significant amount of SO42-deposition was intercepted by the tree canopy in the subalpine plantation,with more SO42-deposition at the gap edge than in the closed canopy,which is beneficial for improving the water quality in the upper reaches of the Yangtze River via forest management.
基金funded by the National Natural Science Foundation of China(31870602,31700542 and 31500509)the National Key R&D Program of China(2017YFC0503906)the Special Fund for Key Program of Science and Technology of Sichuan Province(2018SZDZX0030)。
文摘As an arthropod biocide,naphthalene has been used in studies of the ecological functions of soil fauna for decades.However,its potential non-target effects on soil microorganisms may affect soil mineralization and litter decomposition processes.Therefore,we conducted an experiment with naphthalene adding to soil surface at a rate of 100 g·m-2 per month to examine the potential non-target effects of this treatment on soil fungal phospholipid fatty acids(PLFAs),18 S rDNA gene copy numbers and community diversity in a subalpine forest of western Sichuan,China.The results showed that naphthalene addition significantly increased fungal PLFAs but did not significantly alter fungal gene copy numbers.A total of 16 phyla,62 genera and 147 Operational taxonomic units(OTUs)were identified through Illumina Mi Seq sequencing analysis.Basidiomycota and Ascomycota were the most abundant phyla in both the control and naphthalene addition plots.Naphthalene addition did not affect the diversity or structure of the soil fungal community,but the increase in some genera of Basidiomycota might contribute to the increase in fungal PLFAs in the naphthalene addition plots.These results suggest that naphthalene exerts non-target effects on the active fungal abundance by stimulating the abundance of specific taxa in subalpine forest soils.The non-target effects of naphthalene on the fungal community should be taken into consideration when it is used to exclude soil fauna.
基金Supported by National Natural Science Foundation of China under Grant No.69493502。
文摘A layer of TiO_(x) was deposited on powdery γ-Al_(2)O_(3) by using Sat-target magnetron sputtering in microwave electron cyclotron resonance plasma.A vibrator was developed to coat the γ-Al_(2)O_(3) particles evenly by TiO_(x).The conversion efficiency of methane and both the yield and the selectivity of C_(2) hydrocarbons and C_(2)H_(2) were revealed to be superior to that by conventional chemical method.The use of vibrator is effective.
