Chromium is a potentially toxic and carcinogenic metal originating from natural processes and anthropogenic activities such as the iron steel, electroplating and leather industries. Therefore, ...chromium should be removed from wastewater to avoid environmental pollution and to recycle chromium in the context of the future circular economy. Here we briefly review aqueous Cr species, their toxicity and methods to remove Cr such as membrane filtration, chemical precipitation, ion exchange, adsorption electrocoagulation, electrochemical reduction, electrodialysis, electrodeionization, photocatalysis and nanotechnology.
Cyclobutenones, four‐membered ketones bearing an unsaturated carbon–carbon double bond, and their structural sibling benzocyclobutenones, possess unique reactivity. Owing to their inherent high ring ...strain, such structures readily undergo ring opening under a variety of conditions, including thermolysis, photolysis, and transition metal catalysis, to afford reactive intermediates that can be trapped with nucleophiles, dienophiles, and unsaturated bonds. Their electron‐deficient enone moieties are good electrophiles for facile nucleophilic addition. Such properties render cyclobutenones versatile synthons, serving as excellent coupling partners in a vast array of synthetically valuable transformations.
Square routes: Cyclobutenones and their structural sibling benzocyclobutenones possess unique reactivity due to the ring strain and electron‐deficient enone moieties. Such properties render them serving as excellent coupling partners in a variety of synthetically valuable transformations.
A quantitative method was established to determine the well-known endocrine disruptor bisphenol A (BPA) in barreled drinking water. Samples were pretreated by solid phase extraction (SPE), and then ...analyzed by liquid chromatography-mass spectrometry (LC-MS). Working standard solutions were obtained by pretreatment of a series of aqueous standard solutions over the concentration range of 122.9-1190.7 ng L
−1
. The linear calibration curve was Y = 69.4X + 2206.2 with the correlation coefficient (R
2
) of 0.9929. The average recoveries from spiked samples were more than 91.6%. The relative standard deviations (n = 6) were less than 9.6%. The method allowed the detection of 7.0 ng L
−1
BPA in barreled drinking water. Typical barreled drinking water products in the market were detected. As results, thirty-five of fifty-two commercial samples were found to contain BPA with a maximum concentration of 898.7 ng L
−1
. The occurrence of BPA in barreled drinking water may be due to the pollution of raw water, the inefficiency of purification processes and the migration of BPA from barrels. The daily exposure of adults to BPA through drinking barreled drinking water is far below the current human tolerable daily intake (TDI) set by European Food Safety Authority (EFSA).
The transition-metal-catalyzed “cut and sew” transformation has recently emerged as a useful strategy for preparing complex molecular structures. After oxidative addition of a transition metal into a ...carbon–carbon bond, the resulting two carbon termini can be both functionalized in one step via a following migratory insertion and reductive elimination with unsaturated units, such as alkenes, alkynes, allenes, CO, and polar multiple bonds. Three- or four-membered rings are often employed as reaction partners due to their high ring strains. The participation of nonstrained structures generally relies on cleavage of a polar carbon–CN bond or assistance of a directing group.
Reliability-based design optimization (RBDO) has been widely implemented for engineering design optimization when considering the uncertainty. The single loop approaches (SLA) are highly efficient ...but is prone to converge with inappropriate results for highly nonlinear probabilistic constraints. In this paper, a novel RBDO algorithm is proposed based on single loop approach and the enhanced chaos control method, named as enhanced single-loop method (ESM). The performance of SLA is enhanced using an adaptive inverse reliability method with limited number of iterations. The adaptive step size is computed based on a merit function which is computed using the results of the new and previous iterations. The iterations of the probabilistic constraints of RBDO models are manually controlled in the range from 1 to 10 in ESM. The efficiency and accuracy of the ESM are compared through four nonlinear RBDO problems with complex constraints, including a nonlinear mathematical problem, two engineering problems and a practical complex stiffened panel example with complex buckling constraint for aircraft design. Results illustrate that the proposed ESM is more efficient and robust than the performance measure approach and reliability index approach for RBDO problems.
Liquid metals (LMs) are receiving growing interest in modern technologies for their various advantages. This work reports using elemental sulfur to achieve nanodispersed liquid metals in bulk ...polymers for multifunctional LM‐based materials. Ring‐opening polymerization and inverse vulcanization of elemental sulfur provide many polysulfide loops and thiol groups as effective binding ligands that enable extraordinarily uniform dispersion of liquid metals (≈1 µm) in bulk matrix and improve the mechanical performance of the materials. Interestingly, the liquid‐metal‐embedded sulfur polymer (LMESP) materials exhibit excellent thermal‐/solvent‐processability and recyclability. The uniform dispersion leads to phenomenal electrical conductivity of the LMESP at a low volume percentage of LM (30 vol%), overcoming the issue of nonconductivity typically seen in insulated LM–polymer blends. Additionally, the LMESP shows resistive sensitivity toward external pressure. Furthermore, the LMESP materials exhibit an excellent self‐healing ability under mild conditions via the dynamic bonds between polysulfide loops/thiol groups and liquid metals. This work clearly offers a new platform to design liquid metals and can push them for broad applications.
Elemental sulfur is used to achieve nanodispersed liquid metals (LMs) in bulk polymers for multifunctional LM‐based materials. The resulting liquid‐metal‐embedded sulfur polymer shows unique features in different aspects, including superior dispersion of liquid metals, excellent thermal‐/solvent‐processability and recyclability, improved mechanical performance, phenomenal electrical conductivity, resistive pressure‐sensitivity, and remarkable self‐healing under mild conditions.
A tunable rhodium‐catalyzed intramolecular alkyne insertion reaction proceeding through the CC cleavage of benzocyclobutenones is described. Selective formation of either the direct or ...decarbonylative insertion product can be controlled by using different catalytic systems. A variety of fused β‐naphthol and indene scaffolds were obtained in good yields with high functional group tolerance. This work illustrates a divergent approach to synthesize fused‐ring systems by CC activation/functionalization.
Cat. in control: A tunable rhodium‐catalyzed intramolecular alkyne insertion reaction proceeding through CC cleavage of benzocyclobutenones is described. Selective formation of either the direct or decarbonylative insertion product can be controlled by using different catalytic systems. A variety of fused β‐naphthol and indene scaffolds were obtained in good yields with high functional‐group tolerance.
Treatment selections are very limited for patients with advanced nasopharyngeal carcinoma (NPC) experiencing disease progression. Uncovering mechanisms underlying NPC progression is crucial for the ...development of novel treatments. Here we show that N7-methylguanosine (m7G) tRNA modification enzyme METTL1 and its partner WDR4 are significantly elevated in NPC and are associated with poor prognosis. Loss-of-function and gain-of-function assays demonstrated that METTL1/WDR4 promotes NPC growth and metastasis in vitro and in vivo. Mechanistically, ARNT was identified as an upstream transcription factor regulating METTL1 expression in NPC. METTL1 depletion resulted in decreased m7G tRNA modification and expression, which led to impaired codon recognition during mRNA translation, therefore reducing the translation efficiencies of mRNAs with higher m7G codons. METTL1 upregulated the WNT/β-catenin signaling pathway and promoted NPC cell epithelial-mesenchymal transition (EMT) and chemoresistance to cisplatin and docetaxel in vitro and in vivo. Overexpression of WNT3A bypassed the requirement of METTL1 for EMT and chemoresistance. This work uncovers novel insights into tRNA modification-mediated mRNA translation regulation and highlights the critical function of tRNA modification in cancer progression.
Based on the Wigner function in local equilibrium, we derive hydrodynamical quantities for a system of polarized spin-1/2 particles: the particle number current density, the energy-momentum tensor, ...the spin tensor, and the dipole moment tensor. Compared with ideal hydrodynamics without spin, additional terms at the first and second orders in the Knudsen number
Kn
and the average spin polarization
χ
s
have been derived. The Wigner function can be expressed in terms of matrix-valued distributions, whose equilibrium forms are characterized by thermodynamical parameters in quantum statistics. The equations of motion for these parameters are derived by conservation laws at the leading and next-to-leading order
Kn
and
χ
s
.
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