Search

The cracked pipes usually need to be replaced or conservatively evaluated in the Nuclear Power Plants (NPPs). There is still a lack of effective methods for a real-time crack propagation and safety evaluation based on massive monitoring transient data. From a technical standpoint, there is a need to establish inspection and monitoring technologies. This research has carried out a re-development in the general finite element analysis (FEA) software platform which is based on our research results and the requirements of the RSE-M Code. In this paper, the re-development is introduced firstly. Then, the information of the large pipe test information from France, Japan and China is summarized. Finally, the technology accuracy of the on-line fracture assessment of a cracked pipe in the NPPs is studied. The comparative research results show that the FEA analysis and modeling method of the pipe adopted by the authors in the re-development software is reliable and can meet the requirements for the on-line fracture assessment.

Activated, oxidized, and solvent-extracted black carbon samples (BCs) were produced from a shale kerogen at temperatures ranging from 250 to 500 °C by chemical activation regents (KOH, ZnCl2), oxidative regents (H2O2, NaClO), and organic solvents, respectively. Extracted organic matter (EOM) and polycyclic aromatic hydrocarbons (PAHs) were quantified in BCs, and they increased and then decreased with increasing temperature. Sorption and desorption isotherms of nonylphenol (NP) on BCs were compared with those previously reported for phenanthrene (Phen). The desorption hysteresis coefficients of NP were greater than those of Phen, while the adsorption capacities of NP were different from those of Phen. The micropore volume and micropore size were critical factors for the micropore filling mechanism of NP in BCs. The ZnCl2 activation and oxidation treatments were observed to effectively enhance the adsorption of NP and to remove native PAHs from the investigated BCs. But the KOH activation and oxidation treatments were not as efficient as expected. Moreover, the NP desorption hysteresis suggested that a hydrogen bonding and micropore deformation mechanism occurred on the extracted activated BCs. This finding improves our understanding of the sorption and desorption mechanisms of NP from the perspective of the modified BCs and their applications.

Although spores/pollens are so abundant and ubiquitous in the environment, the role of these natural organic matter concerning fate and transport of organic pollutants in the environment is neglected. Lipid-free fractions and sporopollenins were isolated from seven spores/pollens collected from lower and higher biota species and were characterized by elemental analysis, CO

The demineralized fraction (DM), lipid-free fraction (LF), nonhydrolyzable organic carbon fraction (NHC), and black carbon (BC) were isolated from five marine surface sediments, and they were characterized by elemental analysis as well as CO2 and N2 adsorption techniques, respectively. The NHC fractions were characterized using advanced solid-state 13C nuclear magnetic resonance (NMR) and x-ray photoelectron spectroscopy (XPS). Then, the sorption isotherms of phenanthrene (Phen) and nonylphenol (NP) on all of the samples were investigated by a batch technique. The CO2 micropore volumes were corrected for the outer specific surface areas (SSAs) by using the N2-SSA. Significant correlations between the micropore-filling volumes of Phen and NP and the micropore volumes suggested that the micropore-filling mechanism dominated the Phen and NP sorption. Meanwhile, the (O + N)/C atomic ratios were negatively and significantly correlated with the sorption capacities of Phen and NP, indicating that the sedimentary organic matter (SOM) polarity also played a significant role in the sorption process. In addition, a strong linear correlation was demonstrated between the aromatic C and the sorption capacity of Phen for the NHC fractions. This study demonstrates the importance of the micropores, polarity, and aromaticity on the sorption processes of Phen and NP in the sediments.

A high mobility group box 1 (HMGB1) protein has been reported to recognize both 1,2-intrastrand crosslinked DNA by cisplatin (1,2-cis-Pt-DNA) and monofunctional platinated DNA using trans-[PtCl2(NH3)(thiazole)] (1-trans-PtTz-DNA). However, the molecular basis of recognition between the trans-PtTz-DNA and HMGB1 remains unclear. In the present work, we described a hydrogen/deuterium exchange mass spectrometry (HDX-MS) method in combination with docking simulation to decipher the interactions of platinated DNA with domain A of HMGB1. The global deuterium uptake results indicated that 1-trans-PtTz-DNA bound to HMGB1a slightly tighter than the 1,2-cis-Pt-DNA. The local deuterium uptake at the peptide level revealed that the helices I and II, and loop 1 of HMGB1a were involved in the interactions with both platinated DNA adducts. However, docking simulation disclosed different H-bonding networks and distinct DNA-backbone orientations in the two Pt-DNA-HMGB1a complexes. Moreover, the Phe37 residue of HMGB1a was shown to play a key role in the recognition between HMGB1a and the platinated DNAs. In the cis-Pt-DNA-HMGB1a complex, the phenyl ring of Phe37 intercalates into a hydrophobic notch created by the two platinated guanines, while in the trans-PtTz-DNA-HMGB1a complex the phenyl ring appears to intercalate into a hydrophobic crevice formed by the platinated guanine and the opposite adenine in the complementary strand, forming a penta-layer π-π stacking associated with the adjacent thymine and the thiazole ligand. This work demonstrates that HDX-MS associated with docking simulation is a powerful tool to elucidate the interactions between platinated DNAs and proteins.

I-compounds are age-related bulky DNA modifications that are detected in untreated animals by 32P-postlabeling. To characterize their properties, I-compounds were compared with carcinogen-DNA adducts in liver, kidney and skin of three rodent species. Weanling female Sprague-Dawley rats, ICR mice and Syrian hamsters were fed Teklad LM485 chow diet for 3 months and raised concurrently and strictly under the same environmental conditions. Animals of each species were treated topically with 24 mumol/kg dibenz[a,j]acridine per day for 3 days, then by gavage once with a mixture of safrole and 7,12-dimethylbenz[a]anthracene (60 and 80 mumol/kg respectively), or with one of the individual carcinogens. Liver, kidney and skin DNA from carcinogen-exposed (24 h after treatment) and unexposed animals was analyzed by the monophosphate version of the 32P-postlabeling assay. While each of the three carcinogens produced qualitatively identical major adduct patterns in all samples examined, I-compounds in untreated animals showed distinct species- and tissue-dependent profiles. Rats displayed the highest I-compound levels but the lowest adduct levels in both liver and kidney among the three species. These findings demonstrate fundamental differences between I-compounds and carcinogen-DNA adducts, and support the hypothesis that I-compound formation is primarily related to species-specific, i.e. genetically determined, normal metabolic activities rather than exposure to environmental genotoxic carcinogens.