Lanthanide Complex-Based Luminescent Probes for Highly Sensitive Time-Gated Luminescence Detection of Hypochlorous Acid

Two novel lanthanide complex-based luminescent probes, ANMTTA-Eu and ANMTTA-Tb {ANMTTA, [4′-(4-amino-3- nitrophenoxy)methylene-2,2′:6′,2â-terpyridine-6,6â-diyl] bis(methylenenitrilo) tetrakis(acetic acid)}, have been designed and synthesized for the highly sensitive and selective time-gated luminescence detection of hypochlorous acid (HOCl) in aqueous media. The probes are almost nonluminescent due to the photoinduced electron transfer (PET) process from the 4-amino-3-nitrophenyl moiety to the terpyridine-Ln moiety, which quenches the lanthanide luminescence effectively. Upon reaction with HOCl, the 4-amino-3-nitrophenyl moiety is rapidly cleaved from the probe complexes, which affords strongly luminescent lanthanide complexes HTTA-Eu and HTTA-Tb {HTTA, (4′-hydroxymethyl-2,2′:6′, 2â-terpyridine-6,6â-diyl) bis(methylenenitrilo) tetrakis(acetic acid)}, accompanied by the remarkable luminescence enhancements. The dose-dependent luminescence enhancements show good linearity with detection limits of 1.3 nM and 0.64 nM for HOCl with ANMTTA-Eu and ANMTTA-Tb, respectively. In addition, the luminescence responses of ANMTTA-Eu and ANMTTA-Tb to HOCl are pH-independent with excellent selectivity to distinguish HOCl from other reactive oxygen/nitrogen species (ROS/RNS). The ANMTTA-Ln-loaded HeLa and RAW 264.7 macrophage cells were prepared, and then the exogenous HOCl in HeLa cells and endogenous HOCl in macrophage cells were successfully imaged with time-gated luminescence mode. The results demonstrated the practical applicability of the probes for the cell imaging application

Analysis of containment pressure control strategy in HPR1000 NPP under severe accidents

Containment is the last barrier of preventing the release of radioactive fission products in a nuclear power plant (NPP). It has the top priority of its strategy in a severe accident (SA) to ensure the integrity of containment. Generally, there are two ways for the containment heat removal. One is to set exchangers or sprays to cool the atmosphere in the containment like CPR1000. The other is to set sprays out of the steel containment to remove heat like AP1000. After Fukushima Daiichi nuclear accident, mitigation strategies after severe accidents are focused and specific systems of dealing with containment failure threat are required to design in new built NPPs. HPR1000 is a generation-Ⅲ PWR in China, which deployed the dedicated severe accident (SA) system of containment spray to address the above conditions. Containment spray in HPR1000 has two identical trains isolated physically, and each train is capable to reduce containment pressure after severe accidents. The containment spray system cannot start automatically, but only be started by operator during severe accidents. According to the lessons from Fukushima accident, it is hard for the operator to make the right choice in such a high-pressure environment during severe accidents, so the proper start-up time is better given in advance as possible. This paper assesses the effectiveness of the containment spray, conducts sensitive calculations of different start-up time, and discuss the negative effects of containment spray. Based on the calculation results, insights of containment spray strategy are gained for HPR1000 NPP and the proper start-up time for the strategy of containment spray in SAMG are put forward

Lanthanide Complex-Based Luminescent Probes for Highly Sensitive Time-Gated Luminescence Detection of Hypochlorous Acid

Two novel lanthanide complex-based luminescent probes, ANMTTA-Eu³⁺ and ANMTTA-Tb³⁺ {ANMTTA, [4′-(4-amino-3-nitrophenoxy)­methylene-2,2′:6′,2″-terpyridine-6,6″-diyl] bis­(methylenenitrilo) tetrakis­(acetic acid)}, have been designed and synthesized for the highly sensitive and selective time-gated luminescence detection of hypochlorous acid (HOCl) in aqueous media. The probes are almost nonluminescent due to the photoinduced electron transfer (PET) process from the 4-amino-3-nitrophenyl moiety to the terpyridine-Ln³⁺ moiety, which quenches the lanthanide luminescence effectively. Upon reaction with HOCl, the 4-amino-3-nitrophenyl moiety is rapidly cleaved from the probe complexes, which affords strongly luminescent lanthanide complexes HTTA-Eu³⁺ and HTTA-Tb³⁺ {HTTA, (4′-hydroxymethyl-2,2′:6′,2″-terpyridine-6,6″-diyl) bis­(methylenenitrilo) tetrakis­(acetic acid)}, accompanied by the remarkable luminescence enhancements. The dose-dependent luminescence enhancements show good linearity with detection limits of 1.3 nM and 0.64 nM for HOCl with ANMTTA-Eu³⁺ and ANMTTA-Tb³⁺, respectively. In addition, the luminescence responses of ANMTTA-Eu³⁺ and ANMTTA-Tb³⁺ to HOCl are pH-independent with excellent selectivity to distinguish HOCl from other reactive oxygen/nitrogen species (ROS/RNS). The ANMTTA-Ln³⁺-loaded HeLa and RAW 264.7 macrophage cells were prepared, and then the exogenous HOCl in HeLa cells and endogenous HOCl in macrophage cells were successfully imaged with time-gated luminescence mode. The results demonstrated the practical applicability of the probes for the cell imaging application