[en] A radioimmunoassay for human basic glutathione S-transferase (B-GST) was developed, with the minimal detectable concentration of 0.85 μg/L, the recovery of 95-110%, the coefficient of correlation (r) between serum dilutions and their measured values of 0.999, the intraassay CV of 7.9% (n = 18), the interassay CV of 8.3% (n = 5), the nonspecific binding of 2.2-4.5% and the stability of a month. The serum concentration of B-GST from 70 normal adults was 3.14-1.96 μg/L (X-bar +-S) and the normal range was 0-7.06 μg/L

[en] The ITER test platform contains a reactive power compensation and harmonic suppression system, which consists of the RLC filter branches and thyristor controlled reactor (TCR). When connected to the grid, in order to prevent the negative effects of load rejection on grid, the load rejection overvoltage at 110 kV bus bar by mathematical calculation is analyzed, which shows that there is a high overvoltage on bus bar when the system throws off the load, and its value is not within the allowable range of the national standards and maybe have impact on grid, so we need to take some protective measures. In order to decrease overvoltage, there adds a bypass branch which contains the anti-parallel diode and a resistor to release the main circuit current. The simulation on the whole system with MATLAB verifies the results above. (authors)

[en] According to the operation modes of passive filters, the impedance characteristic of single-tuned and high-pass filter was deduced under equivalent frequency deviation, and a high-precise was proposed. The effectiveness of the two methods is validated during the experimental test of ITER poloidal field power supply. The conclusion would offer useful theoretical and engineering references for ITER reactive power compensation and harmonic filtering system. (authors)

[en] Iron oxide nanoparticles (NPs) possessing peroxidase-like catalytic activity have been widely explored in recent decades, owing to their high stability against harsh conditions, low cost, flexibility in structure design and composition, adjustable activities and excellent biocompatibility in comparison with natural enzymes. Recently, a lot of great achievements have been made in this field of iron oxide nanozymes, however, this research has now reached a bottleneck in that the maximum activity enhancement is difficult to achieve via a material design. Hence, in this work, visible light was introduced to improve the peroxidase-like activity of Fe₂O₃ NPs synthesized via a combination of electrospinning technology and hydrothermal reaction. Our results showed that with the assistance of visible light, Fe₂O₃ NPs exhibited at least 2.2-fold higher peroxidase activity than those tested under darkness, confirming the superiorly visible light promoted peroxidase-like catalytic activity of Fe₂O₃ NPs. Furthermore, the affinity and maximum reaction velocity of Fe₂O₃ nanoflowers (bandgap = 1.78 eV) towards 3,3’,5,5’-tetramethylbenanozymeidine (TMB) were at least over 3.7 and 4.3 times greater than in Fe₂O₃ nanocubes (bandgap = 2.08 eV), suggesting that the reaction performance of semiconductors could be controlled by proper adjustment of the bandgap. Moreover, the Fe₂O₃ NPs were also successfully utilized to detect glucose. Herein, we believe that the present work exhibits a fascinating perspective for peroxidase-like catalytic fields. (paper)

[en] Highlights: • Silver nanoparticles were synthesized using Psidium guajava L. leaf aqueous extracts. • Silver nanoparticles were characterized with UV–Vis, XRD, FTIR, SEM-EDX and TEM. • Silver nanoparticles were spherical shape with average size of about 25 nm. • The synthesized AgNPs exhibited promising antioxidant and antimicrobial activities. - Abstract: The green synthesis of nanoparticles has become increasingly promising due to their potential applications in nanomedicine and materials science. In this study, silver nanoparticles (P-AgNPs) were synthesized from aqueous extracts of P. guajava L. leaf. The synthesized silver nanoparticles were confirmed by UV–vis spectrophotometry at 438 nm. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and zetasizer analyses showed that the average sizes of the P-AgNPs were 20–35 nm, 25 nm, and 25–35 nm, respectively. Element mapping analyses of the P-AgNPs were confirmed by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) analyses. Moreover, FTIR spectra of the synthesized P-AgNPs showed the presence of phyto constituents as capping agents. Zeta potential measurements (−20.17 mV) showed that the synthesized P-AgNPs had reasonably good stability. The in vitro antioxidant properties of the P-AgNPs were evaluated using two different methods. A highly efficient radical scavenging activity of P-AgNPs possessing IC₅₀ values of 52.53 ± 0.31 μg/mL (DPPH) and 55.10 ± 0.29 μg/mL (ABTS⁺) were confirmed. At a concentration of 100 μg/mL, antimicrobial activity assays of the P-AgNPs showed significant inhibition against selected bacteria, S. cerevisiae, A. niger and R. oryzae, especially against Alcaligenes faecalis and Escherichia coli. The present study revealed that the low-cost and environmentally friendly synthesis of P-AgNPs can be widely used in biomedicine, water treatment or purification, and nanobiotechnology.

[en] Gold nanoparticles (Au NPs) have attracted remarkable research interest in heterogeneous catalysis due to their unique physical and chemical properties. However, only small-sized Au NPs (<7 nm) exhibit promising catalytic activity. In this work, dumbbell-like Au NPs (D-Au NPs) with an average size of 37 × 11 nm were prepared by a secondary seed-mediated growth method to serve as novel photocatalysts for ammonia borane (AB) hydrolysis in a solution with a specific pH value. Our results demonstrate that (i) the strengthened localized surface plasmon resonance (LSPR) compensation effect could effectively remedy the loss of catalytic activity resulting from the size enlarging of D-Au NPs, proved by the observation that the heating power of a single Au nanoparticle (Ps) and turnover frequency of AB molecules within 10 min of D-Au NPs are 52.5 and 3.89 times higher, respectively, than those of spherical Au NPs; (ii) the extinction coefficient and Ps of D-Au NPs are almost 2.72 and 2.42 times as high, respectively, as those of rod-like Au NPs, demonstrating the promoting structure-property relationship of the dumbbell-like structure; (iii) when the pH value of the AB solution was lower than 6.0, the hydrolysis rate was highly promoted, indicating that H⁺ ions play an active role in the hydrolysis process. This work greatly extends the application of noble metals and provides a new insight into AB hydrolysis. (paper)

[en] The structure stabilities and electronic properties of Mg-X (X = Ni, Pd, Ti, Nb) interfaces are studied by first-principles calculations, including the atomic mixture effect. In particular, the Mg-X interface structures are systemically investigated by minimizing the lattice mismatch, including the lattice constants, cell area, and included angle of the lattice (cell shape). It is found that the optimal interface matches are 4:7, 3:4, 7:8, 9:4 in surface cell atom numbers (limited up to 10 in consideration of computational cost) for Mg-Ni, Mg-Pd, Mg-Ti, Mg-Nb, and the corresponding interface energies are −0.01, −0.9, 0.4, 0.9 J m⁻², respectively. We find that atomic mixing at the interface affects the strain, and even stablize the interfaces in the large-mismatch cases. Furthermore, exemplified with the Mg-Pd interface, we find the atoms at the interface can be exchanged under practical condition with assitance of vacancies at the interface. (paper)

[en] Litter decomposition is a complex process that is influenced by many different physical, chemical, and biological processes. Environmental variables and leaf litter quality (e.g., nutrient content) are important factors that play a significant role in regulating litter decomposition. In this study, the effects of adding fungi and using different mesh size litter bags on litter (Populus tomentosa Carr. and Salix matsudana Koidz.) decomposition rates and water quality were investigated, and investigate the combination of these factors influences leaf litter decomposition. Dissolved oxygen (DO), chemical oxygen demand (COD), total phosphorus (TP), and ammonia-nitrogen (NH₃-N) were measured during the 112-day experiment. The salix leaf litter (k = 0.045) displayed faster decomposition rates than those of populous leaf litter (k = 0.026). Litter decomposition was initially slow and then accelerated; and by the end of the experiment, the decomposition rate was significantly higher (p = 0.012, p < 0.05) when fungi were added to the treatment process compared to the blank, and litter bags with different mesh sizes did not influence the decomposition rate. The variations in the decomposition rates and nutrient content were influenced by litter quality and a number of environmental factors. The decomposition rate was most influenced by internal factors related to litter quality, including the N/P and C/P ratios of the litter. By quantifying the interact effect of environment and litter nutrient dynamic, to figure out the revetment plant litter decomposition process in a wetland system in biological physical and chemical aspects, which can help us in making the variables that determine decomposition rates important for assessing wetland function.

[en] To examine how two dominant species coexist within a tidal wetland in the Yellow River Delta, we studied the spatial distribution patterns and ecological relationships of Tamarix chinensis and Suaeda salsa. We also analyzed the relationship between these two plant species and soil chemical properties. Nine quadrats were established, and aerial photography was carried out in July 2018 in the study area to investigate plants and soil. Results showed that T. chinensis showed an aggregation distribution at scales of 0–10 m, 0–30 m, and 0–50 m from the sea to inland. Unlike T. chinensis, S. salsa showed an aggregation distribution at approximately 0–50 m in the study area, which meant the aggregation distributions of T. chinensis and S. salsa were found at different scales and S. salsa tended to aggregate distribution compared with T. chinensis. Meanwhile, T. chinensis and S. salsa had negative correlations far from the sea at a scale of 0–20 m and at the offshore area at a scale of 0–30 m. However, in the intermediate area, S. salsa and T. chinensis showed a positive correlation at a scale of 0–30 m. In general, the relationship between the two groups tends to be negatively correlated in a small range. Given that the tidal action decreased from the sea to inland, the driving factors of population aggregation gradually changed from tidal flooding to an interspecific relationship. The different characteristics of the different species may also have had an effect. And the aggregation of adult plant species had a beneficial impact on the establishment and growth of seedlings and plants. Furthermore, soil properties comprised complex actions including environmental conditions and ecological processes. The soil chemical properties such as soil salinity and nutrients were also influenced by the species’ canopy.

[en] In this work, the rationally-designed sharp corners on Au nanorods tremendously improved the catalytic activity, particularly in the presence of visible light irradiation, towards the hydrogenation of 4-nitrophenol to 4-aminophenol. A strikingly increased rate constant of 50.6 g⁻¹ s⁻¹ L was achieved in M-Au-3, which was 41.8 times higher than that of parent Au nanorods under dark conditions. The enhanced activities were proportional to the extent of the protruding sharp corners. Furthermore, remarkably enhanced activities were achieved in novel ternary Au/RGO/TiO₂ sheets, which were endowed with a 52.0 times higher rate constant than that of straight Au nanorods. These remarkably enhanced activities were even higher than those of previously reported 3–5 nm Au and 3 nm Pt nanoparticles. It was systematically observed that there are three aspects to the synergistic effects between Au and RGO sheets: (i) electron transfer from RGO to Au, (ii) a high concentration of p-nitrophenol close to dumbbell-like Au nanorods on RGO sheets, and (iii) increased local reaction temperature from the photothermal effect of both dumbbell-like Au nanorods and RGO sheets. (paper)