[en] Genetic composition of Poa annua populations showed clinal change along an organic pollution gradient. - The population genetic composition of Poa annua L. was studied by starch electrophoresis along a transect running NE from an organic reagents factory at Shanghai, China. Five enzyme systems were stained. We have reached the following preliminary conclusions: (1) Organic pollution has dramatically changed genotypic frequencies at some loci of Poa annua populations. At polluted sites, significant deviations from Hardy-Weinberg equilibrium were observed on loci Sod-1 and Me due to the excess of heterozygote. Especially in the two nearest sites to pollution source, all the individuals were heterozygous at locus Sod-1. The data suggests that heterozygotes were more tolerant to organic pollution than homozygotes, indicating the fitness superiority of heterozygotes. (2) A tendency towards clinal changes of allele frequencies was found at some polymorphic loci. Frequencies of the common alleles at loci Sod-1, Me and Fe-1 increased as the distance to the pollution source increased. (3) The effective number of alleles per locus, and the observed and expected heterozygosity were much higher in the pollution series than in the clear control site (Botanic Park population), but genetic multiplicity (number of alleles per locus) was lower than for the control. (4) Most genetic variability was found within populations, and only 2.56% were among populations of the polluted series. However, 9.48% of the total genetic variation occurred among populations when including the Botanic Park population. The genetic identity between populations of the pollution series (0.9869-1.0000, mean 0.9941) was higher than those between the pollution series and the Botanic Park population. UPGMA divided the five populations into two groups. One contained the four polluted populations, and the other only contained the Botanic Park population

[en] Since the successful synthesis of highly monodispersed iron oxide nanoparticles at the beginning of this century, the biomedical application of these nanoparticles has undergone an explosive growth, becoming the frontier in nanobiology and nanomedicine. In particular, due to their unique properties, magnetic nanoparticles can mediate an external magnetic field and produce physical effects such as induction heat and mechanical force that can further act upon the biotargets on the micro/nano scale. Hence, by using an interdisciplinary approach, novel magnetic nanoparticle based therapeutic modalities that are controllable, safe and accurate are anticipated for disease diagnosis and therapy, so that the therapeutic efficacy and prognosis of diseases can be improved. In this review, the advances in biomedical application of iron oxide nanomaterials in the past five years will be surveyed, and the opportunities and development of these nanomaterials for magnetic resonance imaging, magnetic thermotherapy and biomechanical regulation will be discussed. (authors)

[en] Highlights: • Methodology of the fire resistance experiment of the EPA is determined. • A heat transfer model of EPA is established. • Fire resistance time, thermal stability, and thermal insulation are evaluated. This paper presents an experimental study about the fire resistance characteristics of the low-voltage electrical penetration assembly (EPA). The fire resistance experiment is designed and completed mainly according to the “Fire Resistance Experiment Methods of Building Components (GB/T9978-1999).” A heat transfer model of EPA is established and the characteristics of fire resistance such as fire resistance time, thermal stability, and thermal insulation are evaluated. The results show that the EPA has sufficient fire resistance, which is in full compliance with the design standards which maintaining a life of more than 60 years at 120 °C.

[en] Single-crystalline magnesium oxide (MgO) is a material with outstanding high-temperature resistance and huge potential for use in high-temperature devices, light emitting devices and optical display fields. The investigation of fabricating a microstructure on the MgO substrate using wet etching process is conducted. The temperature and concentration dependence of the etching rate on the materials, and the surface roughness of the microstructure, are explored and analyzed. A microcavity with good profile and low roughness, 80.7 µm in depth and 4 mm in diameter, has been generated on a MgO substrate with a 50% H₃PO₄ etchant solution at ~100 °C. Optical microscopy, atomic force microscopy, scanning electron microscopy, x-ray photoelectron spectroscope and x-ray diffraction analysis are employed to demonstrate the successful application of wet etching for improving the etching rate and surface morphology without the deterioration of the surface roughness. Our work is of fundamental importance in the fabrication of MgO-based devices (such as pressure sensors, vibration sensors and photonic resonators) and the improvement of growth condition of oxide films on MgO substrates. (paper)

[en] Contamination by heavy metals has become a serious environmental pollution issue today due to its potential threat to plant, wildlife, and human health. Photosynthesis, a process in which light energy is used to produce sugar and other organic compounds, is sensitive to heavy metals. In the present study, the response of photosynthetic process and carbon assimilation of Schima superba was investigated under cadmium (Cd) stress. Three Cd concentrations (0, 300, and 600 mg kg⁻¹) were used designated as control (CK), low Cd (L₁), and high Cd treatment (L₂) of plants. Results showed that photosystem II (PSII) acceptor and donor side electron transport were more easily blocked in treatment compared to control, and L₂ have more significant changes than L₁. A substantial decrease of 820 nm reflection curve absorption was observed both in L₁ and L₂ treatments. Special energy fluxes showed significant difference between the control group and the treated group, which indicated that low concentration Cd stress can cause decrease in quantum yield of PSII in plants studied. Non-stomatal factors resulted in a decrease in net photosynthetic rate and a decrease in photosystem activity. Our results suggested that Cd can damage structure and function of the photosynthesis of S. superba young plants.

[en] An ultra-sensitive glyphosate nanosensor, based on carbon dots (CDs), was successfully developed with excellent long-wavelength emission (530 nm), a high quantum yield (41.3%), and an impressive detection limit (0.8 ng·mL⁻¹). This is the lowest value for glyphosate detection achieved by CD-based fluorescence analysis. The sensor was derived from a separate precursor, 1,4-dihydroxyanthraquinone, and was based on the “off-on” fluorescence analysis, where Cu²⁺ acts as a dynamic quencher and glyphosate as a fluorescence restorer (excitation wavelength 460 nm). Trace detection of glyphosate is possible with a wide detection range of 50–1300 ng·mL⁻¹ and spiked recoveries between 93.3 and 110.0%. Exploration in depth confirmed that (1) the fluorescence of CDs was derived from the carbon core, (2) the large sp² conjugated domain consisting of graphitic carbon and nitrogen contributed to the long-wavelength emission, and (3) CDs had an impressive binding interaction with Cu²⁺, which endow high sensitivity to glyphosate detection. The nanosensor has also be used as a dual-mode visual sensor and a smart sensing membrane that can identify glyphosate on the surface of vegetables, thus showing good practical applicability.

[en] In this investigation, a novel Fe₃O₄-enhanced biochar derived from winter melon (Fe₃O₄@WBC) was synthesised by an innovative ethylene glycol reduction and thermal polymerisation approach for efficiently eliminating U(VI) from contaminated environments. The factors influencing uranium(VI) adsorption by Fe₃O₄@WBC, including pH, adsorbent dosage, time, temperature, and initial U(VI) concentration were explored. The material's performance was characterised, and the underlying mechanism of U(VI) removal was analysed using various techniques. The results demonstrated that Fe₃O₄@WBC effectively removed U(VI), achieving a maximum adsorption capacity of 199.84 mg g^-1 at a pH of 5.0. These findings provided a theoretical basis for the treatment of wastewater contaminated with U(VI). (author)

[en] Phytoremediation is a cost-effective and environmentally friendly technology using plants for the cleanup of both inorganic and organic contaminated sites. In this study, a pot culture experiment has been conducted for 180 days in a greenhouse to examine the capability of Koelreuteria paniculata on pyrene (Pyr) dissipation in contaminated soil. Three treatments were employed and they were: (1) polluted soil with K. paniculata fine roots addition (T1), (2) polluted soil with planted seedlings (T2), and (3) polluted soil (C). Results showed Pyr concentration in soils was reduced by 21.4, 36.2, and 86.4% by natural losses, fine roots addition, and planted K. paniculata treatments, respectively, meaning plants substantially enhanced the dissipation of Pyr from soil. Cultivated K. paniculata seedlings significantly increased soil total nitrogen (TN), total organic carbon, dissolved organic carbon (DOC), and microbial biomass carbon, but not total phosphorus, when compared to the control. The removal efficiency of Pyr was lower in the adding of fine roots treatment than in the planted K. paniculata treatment. The principal component analysis indicated the promotional dissipation of Pyr in soil by planted K. paniculata was likely attributed to increased microbial quantity and activity, DOC, and TN content in the rhizosphere. Our results suggest that K. paniculata is a suitable plant species used in phytoremediation for Pyr-contaminated soils and the efficiency on the dissipation of Pyr is considerably enhanced using living plants than adding dead organic matters. The study provided a reference for the application of K. paniculata in the remediation of Pyr-contaminated soil.

[en] Different root exudations can modify the bioavailability of persistent organic pollutants (POPs). Among these exudations, the low molecular weight organic acids play an imperative role in this process. The study was conducted to analyze the effect of phenanthrene (PHE) stress on root exudation variations and changes in its chemical composition in ten urban greening tree species, namely Loropetalum chinense, Gardenia ellis, Photinia fraseri, Ligustrum japonicum, Rhododendron simsii, Osmanthus fragrans, Gardenia jasminoides, Buxus sinica, Camellia sasanqua, and Euonymus japonicas. The experiment was carried out in three PHE concentration treatments (0 mg kg⁻¹ (CK), 200 mg kg⁻¹ (PHE_L), 2000 mg kg⁻¹ (PHE_H)). The root exudates were collected and analyzed by GC-MS method. In total, 673 compounds were identified either with high or low abundance among all species and treatments. Compounds identified in CK, PHE_L, and PHE_H were 240, 180, and 256, respectively. The results illustrated that carbohydrates, phenols, and esters were the dominant compounds, accounted for more than 92%. Principal component analysis depicted that tree species grown in PHE_H showed obvious alteration in compounds of root exudation, whereas little difference was noticed between PHE_L and CK. Phenols (80%) were the most abundant, while nitriles contributed a small portion. Moreover, among all species, R. simsii released the maximum number of compounds, and L. japonicum released the least number of compounds accounting for 89 and 46, respectively. The results achieved here to illustrate that plant type, and PHE stress can significantly change the concentrations and species of root exudates. This study provides the scientific reference for understanding the phenanthrene responsive changes in root exudates and phytoremediation of polycyclic aromatic hydrocarbons (PAHs), as well as a screening of urban greening tree species.