•Different rock-forming minerals present very different microwave absorption capacity to microwave energy.•The test results can be used to estimate the heating behaviors of rocks to microwave ...irradiation.•SEM-EDX technique was used to determine the elemental distribution and mineralogical composition.•Ferrum may influence the interacting mechanisms between rock-forming minerals and microwaves.
The sample will burst into fragment when the thermal stress induced by thermal expansion greater than the ultimate strength of the rock after microwave irradiation. Microwave-assisted rock fragmentation has been illustrated to be potentially beneficial for mineral processing, mining and geotechnical engineering. In order to have a comprehensive understanding on the influence of microwave on thermo-mechanical properties of rocks, it is necessary to investigate the interaction effect between microwaves and the main rock-forming minerals. In this work, eleven rock-forming minerals were tested in a multimode cavity at 2.45GHz with a power of 2kW, subsequently, the Scanning Electron Microscopy–Energy Dispersive X-ray (SEM-EDX) was used to determine the elemental distribution and mineralogical composition of the tested samples. It was observed that different rock-forming minerals present very different susceptibility induced by microwave treatment. Enstatite presents the strongest microwave absorption capacity by a large margin and most of the rock-forming minerals are weak microwave absorbers. It is significant that the results can be used to predict the heating behaviors of rocks subjected to microwave energy. Furthermore, the SEM-EDX elemental analysis demonstrates that the microwave absorption capacity of rock-forming minerals could link to the contribution of the ferrum, which may influence the interacting mechanisms between microwaves and the rock-forming minerals.
Summary Background Human infections with different avian influenza viruses—eg, H5N1, H9N2, and H7N9—have raised concerns about pandemic potential worldwide. We report the first human infection with a ...novel reassortant avian influenza A H10N8 virus. Methods We obtained and analysed clinical, epidemiological, and virological data from a patient from Nanchang City, China. Tracheal aspirate specimens were tested for influenza virus and other possible pathogens by RT-PCR, viral culture, and sequence analyses. A maximum likelihood phylogenetic tree was constructed. Findings A woman aged 73 years presented with fever and was admitted to hospital on Nov 30, 2013. She developed multiple organ failure and died 9 days after illness onset. A novel reassortant avian influenza A H10N8 virus was isolated from the tracheal aspirate specimen obtained from the patient 7 days after onset of illness. Sequence analyses revealed that all the genes of the virus were of avian origin, with six internal genes from avian influenza A H9N2 viruses. The aminoacid motif GlnSerGly at residues 226–228 of the haemagglutinin protein indicated avian-like receptor binding preference. A mixture of glutamic acid and lysine at residue 627 in PB2 protein—which is associated with mammalian adaptation—was detected in the original tracheal aspirate samples. The virus was sensitive to neuraminidase inhibitors. Sputum and blood cultures and deep sequencing analysis indicated no co-infection with bacteria or fungi. Epidemiological investigation established that the patient had visited a live poultry market 4 days before illness onset. Interpretation The novel reassortant H10N8 virus obtained is distinct from previously reported H10N8 viruses. The virus caused human infection and could have been associated with the death of a patient. Funding Emergency Research Project on human infection with avian influenza H7N9 virus, the National Basic Research Program of China, and the National Mega-projects for Infectious Diseases.
A new, high-efficiency technology for fracturing and breaking rocks is required. Due to various advantages including high efficiency, energy-saving, and having no secondary pollution, the technology ...of microwave-induced fracturing of hard rock has been considered as a potential method for rock fracturing and breaking. Aiming at the realisation of two engineering applications: microwave-assisted mechanical rock breaking and stress release from rock masses in deep underground engineering works to prevent geological disasters caused by high-stress concentrations such as rockbursts, a novel (open-type) microwave-induced fracturing apparatus (OMWFA) for fracturing hard rocks was developed. On this basis, the two modes of microwave-induced subsurface fracturing and microwave-induced borehole fracturing of hard rocks were proposed. Due to removal of the restraint of the microwave cavity, OMWFA can be used to fracture large-size rock samples and engineering-scale rock masses. Using the apparatus, the fracturing effects of the two fracturing modes on different dimensions of cuboidal basalt samples were investigated. By combining the microwave-induced fracturing apparatus with a press machine to explore the influence of unidirectional stress on the fracturing effect of microwave treatment on basalt. Moreover, field tests were carried out on rock masses encountered in underground engineering works at Baihetan Hydropower Station in Sichuan Province, China, and the fracturing effects were evaluated by applying a digital borehole televiewer and conducting acoustic wave testing. The results show that the apparatus had favourable fracturing effects on the subsurface and borehole samples of basalt. When no stress was applied, the cracks radially expanded from the approximate centre of the radiant surface and unidirectional stress promoted fracturing. The number and depth of cracks increased with prolonged microwave exposure. After microwave treatment, the P-wave velocity of the samples declined, and the longer the microwave exposure, the more significant the reduction in P-wave velocity was. The results of field test reveal that borehole fracturing can exhibit a favourable effect around boreholes. The sound velocity around the borehole and between the boreholes both declined to some extent. Microwave-induced hard rock fracturing offers guiding significance to those exploring and developing new rock breaking and tunnelling methods, and generally enhances construction safety in deep underground engineering works.
Grain boundary mediated plasticity (e.g., grain rotation and grain boundary sliding) plays a critical role in determining the deformation behavior of polycrystals, which is especially important for ...nanocrystalline metals or plastic deformation at elevated temperatures. However, due to the lack of a theoretical framework, the mechanism of deformation-induced grain rotation has not been well understood. By introducing a disclination-based description, we show that crystal rotation can be captured conveniently through the characteristic rotational vector of a disclination (i.e., the Frank vector). Under the framework of topological defect theory, grain boundary mediated plasticity can be treated as topological reactions between dislocations and disclinations, leading to rigorous predictions of grain/subgrain rotation through a pseudo-inverse solution for the reformulated Frank-Bilby equation. Systematic classifications of grain/subgrain rotation and grain boundary formation are raised for hexagonal close-packed (HCP) metals, which has been validated by Electron-Backscattered Diffraction characterizations in Mg alloys. Our work not only suggests a theoretical approach to investigate grain/subgrain rotation based on the topological correlation between dislocations and disclinations, but also provides a new insight into the plastic behaviors of polycrystalline HCP metals.
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In utero exposure to phthalates may have adverse effects on pregnant women and their offsprings. Therefore, the exposure level of these substances among individuals, particularly among sensitive ...population, is of concern. The objective of the present study is to characterize urinary concentrations of phthalate metabolites at multiple time points during pregnancy in Chinese women. A total of 3455 pregnant women were included from Ma'anshan Birth Cohort in China. Spot urine samples in the morning (8:00–10:00) and questionnaires were obtained at three separate visits (approximately in 10, 26, and 34 gestational weeks). Seven phthalate metabolites from urine samples were analyzed, including monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobutyl phthalate (MBP), mono benzyl phthalate (MBzP), mono-2-ethylhexyl phthalate (MEHP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP). Geometric means of concentrations were ranged from 0.05 to 41.0ng/mL for all the metabolites mentioned above. No individual exposure level was above the 95th percentiles for all the seven phthalates. On the three separate visits, 0.5%, 0.9% and 1.2% of the participants had coexposure to above the 75th percentiles for all metabolites. Taken these visits together, a total of 29 urine samples had concentrations above the 95th percentiles, while 3.0%–5.6% of urine levels were above 75th percentiles for at least one specific phthalate metabolite. We observed moderate intraclass correlation coefficients (ICCs) ranging from 0.44 to 0.56 for MBzP, MEHP and MEP, and lower ICCs, from 0.28 to 0.32, for MMP, MBP, MEOHP and MEHHP. Sampling season was associated with concentrations of all phthalate metabolites, showing heavier exposure was more likely to occur during summer. In summary, phthalate exposure is prevalent in Chinese pregnant women. However, throughout pregnancy coexposure to multiple phthalates at the upper percentile of exposure is infrequent. Mild to moderate temporal stability indicates that a single measurement in spot urine collected in the morning (8:00–10:00) seems not enough to describe throughout pregnancy phthalate exposure. Urinary levels vary by sampling seasons, which should be taken into consideration in future analyses.
The unadjusted and creatinine-adjusted concentrations of urinary phthalate metabolites. Display omitted
•Phthalate exposure is prevalent in Chinese pregnant women.•Coexposure to multiple phthalates at high-doses is infrequent among Chinese pregnant women.•Throughout pregnancy exposure to one specific phthalate at high-dose is infrequent.•Exposure to phthalates during pregnancy is mild to moderate temporal stability.•Urinary levels of all the phthalate metabolites vary by sampling seasons.
Marine toxins can lead to varying degrees of human poisoning, often resulting in fatal symptoms and causing significant economic losses in seafood-producing regions. To gain a deeper comprehension of ...the role of marine toxins in seafood and their impact on the environment, it is imperative to develop rapid, cost-effective, environmentally friendly, and efficient methods for sample pretreatment and determination to mitigate adverse impacts of marine toxins. This review presents a comprehensive overview of advancements made in sample pretreatment and determination techniques for marine toxins since 2017. The advantages and disadvantages of various technologies were critically examined. Additionally, the current challenges and future development strategies for the analysis of marine toxins are provided.
A novel imine-linked magnetic covalent organic polymer, Fe
3
O
4
@TAB-TFPT, was synthesized using environmentally friendly deep eutectic solvents as the reaction medium instead of conventional ...organic solvents. The materials were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), FT-IR, N
2
adsorption-desorption isotherms, energy dispersive spectrometer (EDS), X-ray photoelectron spectra (XPS), and thermo gravimetric analysis (TGA). Subsequently, the materials were employed as an adsorbent for magnetic solid-phase extraction (MSPE) of flavonoids, including Kurarinone, Norkurarinone, Xanthohumol, and Isoxanthohumol, prior to their determination by HPLC–MS/MS. The validation results demonstrate good linearity within the concentration range 0.1–1000 ng∙mL
−1
(
R
2
≥ 0.9963), high enrichment factors ranging from 18.9 to 30.7, and low LODs (0.01–0.05 ng∙mL
−1
) and LOQs (0.05–0.1 ng∙mL
−1
). Furthermore, recoveries between 80.60% and 108.40% with relative standard deviations ≤ 8.49% were achieved. The proposed MSPE-HPLC–MS/MS method was successfully applied to the determination of flavonoids in
Sophora flavescens
Aition sample.
Graphical Abstract
SUMMARY
The mitochondrial alternative pathway (AP) represents an important photoprotective mechanism for the chloroplast, but the temperature sensitivity of its photoprotective role is unknown. In ...this study, using the aox1a Arabidopsis mutant, the photoprotective role of the AP was verified under various temperatures, and the mechanism underlying the temperature sensitivity of the AP’s photoprotective role was clarified. It was observed that the photoprotective role of the AP increased with rising temperature but was absent at low temperature. The photoprotective role of the AP was severely reduced under non‐photorespiratory conditions. Disturbance of the AP inhibited the conversion of glycine to serine in mitochondria, which may restrain upstream photorespiratory metabolism and aggravate photoinhibition. With rising temperatures, photorespiration accelerated and the restraint of photorespiration caused by disturbance of the AP also increased, determining the temperature sensitivity of the AP’s photoprotective role. We also verified that not only the AP but also the cytochrome pathway in mitochondria contributes to photoprotection by maintaining photorespiration.
Significance Statement
Photoprotection by the mitochondrial alternative pathway (AP) is enhanced at heat but disabled at chilling, which is due to (i) the AP’s contribution to photoprotection through maintaining photorespiration and (ii) acceleration of photorespiration with rising temperatures.
Guided by an MS/MS‐based molecular networking, six undescribed cassane diterpenoids and three known ones were isolated and identified from the seeds of Caesalpinia sappan. Their structures were ...unequivocally elucidated by extensive spectroscopic analyses and electronic circular dichroism (ECD) calculations. Cytotoxic evaluation showed that phanginin JA exhibited significant antiproliferative activities against human non‐small cell lung cancer (A549) cells with IC50 values of 16.79±0.83 μM. Further flow cytometry analysis revealed that phanginin JA could exert apoptotic effect of A549 cells by arresting cell cycle in G0/G1 phase.
Two new triterpenoids (1–2), along with six known analogues (3–8) were obtained from the dried whole plant of Leptopus clarkei. Compound 1 is a 3,4‐seco‐lupane‐type triterpenoid, and compound 2 is a ...phenylpropanoid‐conjugated pentacyclic triterpenoid possessing trans‐p‐coumaroyl unit attached to oleanane‐type skeleton. This is the first report on chemical investigation of the L. clarkei, and the triterpenoid derivatives were found in this plant for the first time. The structures of the new compounds were unequivocally elucidated by HRESIMS and 1D/2D NMR data. Additionally, the isolated compounds were evaluated for theircytotoxicities against four cancer cell lines including HepG2, MCF‐7, A549 and HeLa. Notably, compound 2 exhibited the most significant antiproliferative activity with IC50 less than 20 μM for four cancer lines.
