目的对比研究^(18)F-NaF PET全身骨显像与^(99)Tc^(m)-MDP SPECT全身骨显像图像质量和辐射剂量率。方法收集2021年10月至2022年1月在桂林医学院附属核医学科行全身骨显像的患者97例,分别行^(99)Tc^(m)-MDP和^(18)F-NaF显像。收集患者相...目的对比研究^(18)F-NaF PET全身骨显像与^(99)Tc^(m)-MDP SPECT全身骨显像图像质量和辐射剂量率。方法收集2021年10月至2022年1月在桂林医学院附属核医学科行全身骨显像的患者97例,分别行^(99)Tc^(m)-MDP和^(18)F-NaF显像。收集患者相关临床资料、注射后检查等待时间、检查结束后及24h的1m距离的平均辐射剂量率及诊断医师对两种显像的图像质量,并对两种显像剂患者组间差异进行比较。结果^(18)F-NaF全身骨显像注射后检查等待时间明显少于^(99)Tc^(m)-MDP全身骨显像,且差异具有统计学意义(P<0.001);18 F-NaF全身骨显像图像质量高于^(99)Tc^(m)-MDP全身骨显像,图像质量评分(2.8±0.4 vs 2.1±0.7,t=-6.767,P<0.001),且差异有统计学意义。检查后^(18)F-NaF全身骨显像对周围环境的辐射剂量率高于^(99)Tc^(m)-MDP全身骨显像,且差异具有统计学意义(17.2±6.3μSv/h vs 5.7±4.9μSv/h,t=-9.278,P<0.001)。而24h后两显像方式的辐射剂量率相似,且差异不具有统计学意义(0.5±0.3μSv/h vs 0.6±0.3μSv/h,t=1.653,P=0.102)。结论18 F-NaF全身骨显像较^(99)Tc^(m)-MDP全身骨显像缩短了检查等待时间,并具有更高的图像质量和评分一致性。另外,两种显像剂检查后24h辐射剂量率相似。展开更多
Relationships between fluorescence parameters and membrane lipid peroxidation in leaves of indica and japonica rice (Oryza sativa L.) during later growth stage were studied under chilling temperature and strong light ...Relationships between fluorescence parameters and membrane lipid peroxidation in leaves of indica and japonica rice (Oryza sativa L.) during later growth stage were studied under chilling temperature and strong light stress conditions. Results showed that D1 protein contents of PSⅡ in photosynthetic apparatus dropped, the generation of antheraxanthin (A) and zeaxanthin (Z) of xanthophyll cycle were inhibited partly, PSⅡ photochemical efficiency (F v/F m)and non-photochemical quenching (q N) were also decreased obviously. In addition, endogenous active oxygen scavenger—superoxide dismutase (SOD) reduced, superoxide anion radical (O -· 2) and malondialdehyde (MDA) accumulated, as a result, photooxidation of leaves occurred under chilling temperature and strong light stress conditions. Obvious differences in the changes of the above mentioned physiological parameters between indica and japonica rice were observed. Experiments in leaves treated with inhibitors under chilling temperature and strong light conditions showed that indica rice was more sensitive to chilling temperature with strong light and subjected to photooxidation more than japonica rice. Notable positive correlation between D1 protein contents and F v/F m or (A+Z)/(A+Z+V), and a marked negative correlation between F v/F m and MDA contents were obtained by regression analysis in indica and japonica rice during chilling temperature and strong light conditions. According to the facts mentioned above, it was inferred that PSⅡ photochemical efficiency(F v/F m) was the key index to forecast for the prediction of photooxidation under stress circumstances and the physiological basis were the synthetic capacity of D1 protein and the protection of xanthophyll cycle.展开更多
采用Gleeble-3500对铁素体/马氏体(F/M)钢的热成形规律进行了研究。基于F/M钢热压缩应力-应变曲线,建立了F/M钢动态材料模型(dynamic material model,DMM)热加工图,并通过金相分析对热加工图进行了验证。结合热加工图和金相分析,研究了...采用Gleeble-3500对铁素体/马氏体(F/M)钢的热成形规律进行了研究。基于F/M钢热压缩应力-应变曲线,建立了F/M钢动态材料模型(dynamic material model,DMM)热加工图,并通过金相分析对热加工图进行了验证。结合热加工图和金相分析,研究了F/M钢热成形过程中的组织变化,给出了不同情况下的热加工参数:如后续需要继续大变形加工,可采用850℃、应变速率0.01 s^-1作为加工参数,该参数可生成细小、均匀且易加工的铁素体组织;如后续对F/M钢有较高的强度要求,可选取1150℃、应变速率10 s^-1作为加工参数,该参数可生成细小、均匀且高强度的马氏体。展开更多
文摘目的对比研究^(18)F-NaF PET全身骨显像与^(99)Tc^(m)-MDP SPECT全身骨显像图像质量和辐射剂量率。方法收集2021年10月至2022年1月在桂林医学院附属核医学科行全身骨显像的患者97例,分别行^(99)Tc^(m)-MDP和^(18)F-NaF显像。收集患者相关临床资料、注射后检查等待时间、检查结束后及24h的1m距离的平均辐射剂量率及诊断医师对两种显像的图像质量,并对两种显像剂患者组间差异进行比较。结果^(18)F-NaF全身骨显像注射后检查等待时间明显少于^(99)Tc^(m)-MDP全身骨显像,且差异具有统计学意义(P<0.001);18 F-NaF全身骨显像图像质量高于^(99)Tc^(m)-MDP全身骨显像,图像质量评分(2.8±0.4 vs 2.1±0.7,t=-6.767,P<0.001),且差异有统计学意义。检查后^(18)F-NaF全身骨显像对周围环境的辐射剂量率高于^(99)Tc^(m)-MDP全身骨显像,且差异具有统计学意义(17.2±6.3μSv/h vs 5.7±4.9μSv/h,t=-9.278,P<0.001)。而24h后两显像方式的辐射剂量率相似,且差异不具有统计学意义(0.5±0.3μSv/h vs 0.6±0.3μSv/h,t=1.653,P=0.102)。结论18 F-NaF全身骨显像较^(99)Tc^(m)-MDP全身骨显像缩短了检查等待时间,并具有更高的图像质量和评分一致性。另外,两种显像剂检查后24h辐射剂量率相似。
文摘Relationships between fluorescence parameters and membrane lipid peroxidation in leaves of indica and japonica rice (Oryza sativa L.) during later growth stage were studied under chilling temperature and strong light stress conditions. Results showed that D1 protein contents of PSⅡ in photosynthetic apparatus dropped, the generation of antheraxanthin (A) and zeaxanthin (Z) of xanthophyll cycle were inhibited partly, PSⅡ photochemical efficiency (F v/F m)and non-photochemical quenching (q N) were also decreased obviously. In addition, endogenous active oxygen scavenger—superoxide dismutase (SOD) reduced, superoxide anion radical (O -· 2) and malondialdehyde (MDA) accumulated, as a result, photooxidation of leaves occurred under chilling temperature and strong light stress conditions. Obvious differences in the changes of the above mentioned physiological parameters between indica and japonica rice were observed. Experiments in leaves treated with inhibitors under chilling temperature and strong light conditions showed that indica rice was more sensitive to chilling temperature with strong light and subjected to photooxidation more than japonica rice. Notable positive correlation between D1 protein contents and F v/F m or (A+Z)/(A+Z+V), and a marked negative correlation between F v/F m and MDA contents were obtained by regression analysis in indica and japonica rice during chilling temperature and strong light conditions. According to the facts mentioned above, it was inferred that PSⅡ photochemical efficiency(F v/F m) was the key index to forecast for the prediction of photooxidation under stress circumstances and the physiological basis were the synthetic capacity of D1 protein and the protection of xanthophyll cycle.
文摘采用Gleeble-3500对铁素体/马氏体(F/M)钢的热成形规律进行了研究。基于F/M钢热压缩应力-应变曲线,建立了F/M钢动态材料模型(dynamic material model,DMM)热加工图,并通过金相分析对热加工图进行了验证。结合热加工图和金相分析,研究了F/M钢热成形过程中的组织变化,给出了不同情况下的热加工参数:如后续需要继续大变形加工,可采用850℃、应变速率0.01 s^-1作为加工参数,该参数可生成细小、均匀且易加工的铁素体组织;如后续对F/M钢有较高的强度要求,可选取1150℃、应变速率10 s^-1作为加工参数,该参数可生成细小、均匀且高强度的马氏体。
