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An experiment was conducted to investigate flow-induced vibration (FIV) in the control rods of a pressurized-water reactor (PWR). Control rods and a guide cylinder (full scale compared with the real structure) were installed on an FIV experiment platform, with which flow distributions were simulated according to actual situations. The vibration displacements of the control rods were observed in different flow rate ranges of transverse and vertical flows. Several FIV characteristics of the control rods under different transverse and vertical flows were determined by analyzing the experimental results. A formula was also proposed to predict vibration.Key words: flow-induced vibration, control rod, PWR, prediction, vertical flow, transverse flow.Nous procedons a une experience pour examiner la vibration induite par le flot (VIF) dans les tiges de controle d'un reacteur a eau pressurisee. Des tiges de controle et un cylindre guide (pleine echelle par rapport a la vraie structure) sont installes sur une plateforme experimentale, dans laquelle les distributions de flot sont simulees selon des situations reelles. Nous observons les deplacements vibrationnels des tiges de controle pour differents domaines de taux de flots transverses et verticaux. En analysant les resultats, nous determinons les caracteristiques des VIF des tiges de controle et nous proposons une formule pour predire ces vibrations. [Traduit par la Redaction]Mots-cles : dynamique des fluides, vibration induite par un flot, flot vertical, flot transverse, tige de controle., 1. IntroductionVarious flow-induced vibration (FIV) accidents have occurred since the operation of the first pressurized-water reactor (PWR) in the 1960s. Serious accidents caused by the FIV problem have elicited much [...]

A mononuclear compound, [Co(L1)2(H2O)]·2H2O (1), where L1 = N,N-bis(3,5-dichlorosalicylidene)hydrazine, was synthesized under hydrothermal conditions. Note that L1 is derived from the hydrothermal in situ reaction of L2 (L2 = 3,5-dichlorosalicylaldehyde thiosemicarbazone). L2 is prepared by reflux using 3,5-dichlorosalicylic aldehyde and thiosemicarbazide. Although 1 is only a mononuclear structure coordinated with L1, intermolecular hydrogen-bonded interactions between two adjacent mononuclear units creates a 1D supramolecular chain. Furthermore, it self-assembles into a fascinating 2D supramolecular layer via π⋅⋅⋅π stacking between benzene rings of adjacent chains. Hirshfeld surfaces and fingerprint maps of 1 were applied to obtain data on non-covalent interactions. Antibacterial analysis shows that 1 is a potential antibacterial material and the bacteriostasis rate is higher than that of L1 (E. coli: 89.41% for 1, 29.09% for L1; MRSA: 93.17% for 1, 38.54% for L1). The solid and liquid photoluminescence properties of 1 and L1 were also investigated. [ABSTRACT FROM AUTHOR]

Graphdiyne (g−CnH2n‐2), a novel two‐dimension carbon allotrope material composed of a sp‐ and sp2‐hybrid carbon network, has been widely explored since it was synthesized for the first time by Li's group in 2010. A series distinct and excellent properties bestow graphdiyne excellent performance in many fields. Here, an innovative progress for preparing graphdiyne by using Cu+ contained material as catalyst is reported and the composite CuI‐GD is coupled with flower‐like NiAl‐LDH to produce H2 from photocatalytic water splitting. The results of FTIR and Raman spectroscopy together reveal that graphdiyne nanosheets are synthesized successfully by employing a cross‐coupling method. Photocatalytic hydrogen evolution performance shows that the hydrogen production activity of CuI‐GD/NiAl‐LDH has a 15‐ and 216‐fold enhancement compared with CuI‐GD and NiAl‐LDH, respectively. A series of characterizations are carried out to expound the underlying reasons in the enhancement of the photocatalytic hydrogen production performance of CuI‐GD/NiAl‐LDH. Meanwhile, a possible mechanism for the photocatalytic hydrogen evolution process was proposed to understand the interaction among these materials. [ABSTRACT FROM AUTHOR]

A new strategy of redox mediator immobilization was developed by coating polydopamine (PDA) on individual live cells to enhance extracellular electron transfer. As a result of the synergistic effect of the redox properties of PDA and the ability to adsorb self-secreted flavin molecules, a double-mediator electron transport channel was achieved. [ABSTRACT FROM AUTHOR]

We studied the effects of copper (Cu) phytoremediation on microbial community composition under laboratory conditions. A Cu accumulator, Commelina communis, was grown on a soil containing different gradients of Cu. Results showed that the biomass of C. communis grown with Cu differed from that of the control. Concentrations of Cu in the shoots of C. communis were 73.6, 160.9, and 319.1 mg kg-1 under 200, 500, and 1000 mg kg-1 Cu treatments, respectively. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprint analysis revealed that additions of Cu decreased the number of bands in the soil with C. communis or without plants. The principal component analysis explained 52.7% of the variance for the different rhizospheres of soil and Cu treatments in the soil samples. These results indicated significant effects on soil bacteria activity and community composition in the rhizosphere of C. communis and provided a basis for further studies of metal-accumulator plant effects on soil microorganisms. [ABSTRACT FROM AUTHOR]

Abstract: All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciation and availability. We studied the effects of heavy metal speciation and availability on soil microorganism activities along a Cu/Zn contamination gradient. Microbial biomass and enzyme activity of soil contaminated with both Cu and Zn were investigated. The results showed that microbial biomass was negatively affected by the elevated metal levels. The microbial biomass-C (Cmic)/organic C (Corg) ratio was closely correlated to heavy metal stress. There were negative correlations between soil microbial biomass, phosphatase activity and NH4NO3 extractable heavy metals. The soil microorganism activity could be predicted using empirical models with the availability of Cu and Zn. We observed that 72% of the variation in phosphatase activity could be explained by the NH4NO3-extractable and total heavy metal concentration. By considering different monitoring approaches and different viewpoints, this set of methods applied in this study seemed sensitive to site differences and contributed to a better understanding of the effects of heavy metals on the size and activity of microorganisms in soils. The data presented demonstrate the relationship between heavy metals availability and heavy metal toxicity to soil microorganism along a contamination gradient. [Copyright &y& Elsevier]

Abstract: The role of rhizosphere bacteria in facilitating the solubility of copper (Cu) in contaminated soil and Cu accumulation in plant were studied. The bacteria strains were isolated from the rhizosphere of Elsholtzia splendens, a Cu accumulator growing on Tonglu Mountain copper mines. After the sandy soils containing 237 mg kg−1 were incubated with the bacteria strains, it was indicated that rhizosphere microbes played an important role in influencing the availability of water-soluble Cu in soils. Soils had greater concentrations of water-extractable Cu compared with axenic soils inoculated with different bacterial strains. Further evidence for bacterial facilitation of increased solubility of Cu in the soil was obtained using the antibiotic ampicillin (0.1 mg g− 1). There were 36% decreases in Cu concentration in the presence of bacterial strain MS12 and ampicillin together compared with bacterial inoculation alone. Different bacterial strains had different abilities on soil water-soluble Cu. To achieve the highest rates of plant Cu accumulation, it was necessary for bacteria to be present in the rhizosphere of E. splendens. Inoculated plants supplied with 20 μmol L− 1 CuSO4 had significantly greater concentrations of Cu in shoots and roots than uninoculated plants and bacterial strain MS2 was the most effective strain in promoting plant Cu uptake. There were 2.2-fold and 2.5-fold increases in Cu accumulation in the shoots and roots of plants inoculated with strain MS2 compared to axenic controls. Furthermore, when ampicillin and the bacterial strains were added together to the nutrient solution, the Cu concentrations in roots and shoots of ampicillin-treated plants were lower than those in inoculated plants. When ampicillin was added to the nutrient solution, Cu accumulation was inhibited by about 24–44% in shoots and 20–44% in roots. The above results provided a new insight into the phytoremediation of Cu-contaminated soil. [Copyright &y& Elsevier]

Graphdiyne (g-C n H 2n-2 ), a novel two-dimension carbon allotrope material composed of a sp- and sp 2 -hybrid carbon network, has been widely explored since it was synthesized for the first time by Li's group in 2010. A series distinct and excellent properties bestow graphdiyne excellent performance in many fields. Here, an innovative progress for preparing graphdiyne by using Cu + contained material as catalyst is reported and the composite CuI-GD is coupled with flower-like NiAl-LDH to produce H 2 from photocatalytic water splitting. The results of FTIR and Raman spectroscopy together reveal that graphdiyne nanosheets are synthesized successfully by employing a cross-coupling method. Photocatalytic hydrogen evolution performance shows that the hydrogen production activity of CuI-GD/NiAl-LDH has a 15- and 216-fold enhancement compared with CuI-GD and NiAl-LDH, respectively. A series of characterizations are carried out to expound the underlying reasons in the enhancement of the photocatalytic hydrogen production performance of CuI-GD/NiAl-LDH. Meanwhile, a possible mechanism for the photocatalytic hydrogen evolution process was proposed to understand the interaction among these materials., (© 2021 Wiley-VCH GmbH.)

Objective: To investigate the effect of luteolin on cell growth and apoptosis of HepG2 cells in vitro., Methods: Cultured HepG2,HL60,A549 and LO2 cells were treated with luteolin for different doses (0 μg/ml,2.5 μg/ml,10 μg/ml and 20 μg/ml) and varied times (0 h,24 h,48 h and 72 h). Cell viability was measured with MTT assay and IC50 was calculated. The reactive oxygen species (ROS) levels in HepG2 cells treated with luteolin for 6 h and 12 h were measured with flow cytometry. Cell apoptosis of HepG2 cells treated with luteolin for 24h was examined with flow cytometry and Annexin V-FITC/PI. Expression levels of apoptosis pathway proteins (p53,ASPP2 and iASPP) in HepG2 cells were detected with western blot and the dose and time-effect was analyzed., Results: Luteolin effectively inhibited tumor cell proliferation in a dose-and time-dependent manner,and the inhibition rates of 20 μg/ml Luteolin for 72 h were 39.34%,62.90%,57.57% and 62.90% to LO2,HepG2, HL60 and A549 cells,respectively. The intracellular ROS level was decreased in HepG2 cells by 13.88% and 41.11% after being treated with luteolin for 6 h and 12 h,respectively. The apoptosis rate of HepG2 cells treated with luteolin for 24 h was 14.43%,and western blot showed that luteolin reduced the expression level of iASPP by 77.07% and up-regulated the expression of p53 by 179.37% and ASPP2 by 725.02% in HepG2 cells treated with luteolin for 12 h., Conclusion: Luteolin has ant-proliferative and pro-apoptotic activity on hepatoma HepG2 cells, which is associated with the altered expression of pro-apoptotic factors and decreased ROS level in HepG2 cells.

As a new DNA fingerprinting technique, denaturing gradient gel electrophoresis (DGGE) can be used to analyze the microbial diversity in different environmental samples. Three biofilters treating air loaded with ammonia will be studied with respect to microbial diversity by applying cultivation-independent molecular methods DGGE. The principal objectives of this paper include the development and application of a suitable set of molecular tools to deliver information about the possible microbial community changes within carriers during treatment of ammonia-contaminated gas. Carriers were sampled at different time during operation of biofilters. After extraction and purification of the genomic DNA, the 16S rRNA genes (V3 region) were amplified by using the specific primers. These amplified DNA fragments were then separated by paralleled DGGE. The profile of DGGE showed that the same carrier at different time had the different bands' patterns. The structural diversity of the microbial community was examined by the Shannon index of general diversity H. Shannon indexes of three kinds of carriers all showed a decrease with time, which had a similar trend to NH3 removal efficiency.