•Field trials on the use of MICP for wind erosion control of desert soil are conducted.•Soil crusts on loose cohesionless desert soil exist after MICP treatment.•MICP shows pleasurable ecological ...compatibility and long-term sustainability.•MICP is a promising candidate to mitigate wind erosion of desert soils in drylands.
This study examined the potential of microbially induced carbonate precipitation (MICP) in reducing wind erosion of desert soil. Field tests were conducted on artificial mounds and bare sandy land located in Ulan Buh Desert, Ningxia Hui Autonomous Region, China. Results showed that the MICP method could significantly enhance the bearing capacity and wind erosion resistance of the surficial soil through the formation of soil crusts. The optimal cementation solution (containing equimolar urea and calcium chloride) concentration and spraying volume, were 0.2 M and 4 L/m2, respectively. Under this condition, the soil crusts, with a thickness of 12.5 mm and a calcium carbonate (CaCO3) content of 0.57%, remained intact on the surface of man-made mounds after being exposed to a 30 m/s wind for 2 min. For the sandy land, the soil bearing capacity could reach its maximum of 459.9 kPa (as measured with a 6 mm-diameter handheld penetrometer) within three days, and the depth of wind erosion was approximately zero after 30 days of exposure to the local weather conditions. Furthermore, the biocementation method showed its ecological compatibility at the optimal dosage. Scanning electron microscopy (SEM) tests with energy dispersive X-ray (EDX) confirmed the bridge effect of CaCO3 crystals. Longer-term durability of MICP treatment was evaluated, and the results showed that soil bearing capacity and wind erosion resistance of the sandy land was significantly improved over 180 days. These findings suggest that MICP is a promising candidate to protect desert soils from wind erosion.
Enzyme-induced carbonate precipitation (EICP) is a potential method to improve the mechanical properties of granular soil. The one-phase premixed percolation method using purified urease enzyme is ...widely adopted for in-situ EICP treatment currently, but it is expensive and uses a relatively large amount of urease. This paper proposes a multiple-phase method consisting of a percolation of premixed soybean crude urease and cementation solution followed by several percolations of cementation solution in one cycle of biocementation. The utilizing rate of urease was increased by at least four times for the production of precipitated carbonate compared with the one-phase method. The proposed method also weakened the clogging of carbonate precipitation, thus bringing out a relatively uniform EICP treatment. After four cycles of biocementation (each cycle included five applications of cementation solution), the unconfined compressive strength of EICP-treated ASTM C778-graded sand exceeded 10 MPa with a CaCO3 content of ~20%.
•Soybean crude urease was employed to catalyze CaCO3 precipitation via EICP.•A multiple-phase EICP method was proposed for soil improvement.•The proposed method could significantly improve utilization efficiency of urease.•A relatively uniform CaCO3 precipitation was obtained in EICP-treated sand.•The UCS of EICP-treated sand exceeded 10 MPa with a CaCO3 content of ~20%.
Abstract
Synthetic macrocycles have proved to be of great application value in functional charge-transfer systems in the solid state in recent years. Here we show a switchable on-off type vapochromic ...system toward 1-/2-bromoalkane isomers by constructing solid-state charge-transfer complexes between electron-rich perethylated pillar5arene and electron-deficient aromatic acceptors including 4-nitrobenzonitrile and 1,4-dinitrobenzene. These charge-transfer complexes with different colors show opposite color changes upon exposure to the vapors of 1-bromoalkanes (fading) and 2-bromoalkanes (deepening). Single-crystal structures incorporating X-ray powder diffraction and spectral analyses demonstrate that this on-off type vapochromic behavior is mainly attributed to the destruction (off) and reconstruction (on) of the charge-transfer interactions between perethylated pillar5arene and the acceptors, for which the competitive host-guest binding of 1-bromoalkanes and the solid-state structural transformation triggered by 2-bromoalkanes are respectively responsible. This work provides a simple colorimetric method for distinguishing positional isomers with similar physical and chemical properties.
Covalent organic frameworks (COFs) are an emerging class of crystalline porous materials with tailor-made functionalities for improved photocatalytic activity. However, limited choice of building ...blocks greatly restricts the photochemical performance and application scope of COFs in photocatalysis. Herein, a covalent hybridization approach is reported to address these issues by knitting rigid macrocyclic struts, namely, pillararenes, into the extended network of COFs. Varying different ratios of pillararenes with unique conformations and electron-rich cavities can not only generate a confined molecular space for exciton migration and carrier transport but also create new interfaces to interplay with photogenerated charge carriers, leading to high performance in promoting efficient oxidation of amines to imines. This work paves the way for constructing macrocycle-derived COFs and provides a promising molecular platform for photocatalysis through predesign and functionalization of the pore surface.
Overproduction of pro-inflammatory cytokines in the aged, which is called inflammaging, leads to the deterioration of periodontitis. Toll-like receptor 4 (TLR4) plays a role in the regulation of ...cellular senescence, and its expression increases with age. However, there has been limited research into the molecular mechanisms underlying the onset of periodontal inflammaging, and the interplay between TLR4 and inflammaging. In the present study, wild-type and TLR4 gene knockout mice were used to investigate the activation of the TLR4 pathway in mouse periodontitis and the expression of the nucleotide-binding and oligomerization domain-like receptor 3 (NLRP3) inflammasome, an upstream immune checkpoint during the development of inflammaging. Activation of TLR4 in a mouse model of periodontitis enhanced the expression of a senescence-associated secretory phenotype (SASP), which boosted the inflammaging process. conversely, TLR4 activation downregulated the expression of B cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1) and promoted the priming of NLRP3 inflammasome, both of which are regulators of SASP. Treating gingival fibroblasts with Bmi-1 inhibitor PTC209, it was demonstrated that TLR4 activated the NLRP3 pathway and the inflammaging process by suppressing Bmi-1. In addition, there was a significant reduction in the expression of Bmi-1 expression in the gingiva of patients with periodontitis compared with healthy controls. In conclusion, the present study demonstrated that TLR4 acted by inhibiting Bmi-1 to enhance the NLRP3 pathway and SASP factors. This cascade of reactions may contribute to the senescence of the periodontium. Key words: periodontitis, inflammaging, senescence-associated secretory phenotype, Toll-like receptor 4, B cell-specific Moloney murine leukemia virus integration site 1, nucleotide-binding and oligomerization domain-like receptor 3
Modulating intermolecular charge‐transfer (ICT) interactions between specific donor and acceptor species in host–guest systems is a big challenge and full of research value in supramolecular ...chemistry and materials science. In this work, a strategy to modulate the supramolecular ICT interactions in the solid state is developed by compressing the binding cavity of a macrocyclic host named perethylated leaning pillar6arene (p‐EtLP6). The solid‐state ICT affinities of p‐EtLP6 toward multi‐types of electron‐deficient planar guests could be significantly enhanced by transforming the macrocyclic backbone from the original para‐bridged mode into a hybrid para‐ and meta‐bridged isomeric form (m‐EtLP6). X‐ray single‐crystal structural analyses incorporating theoretical calculation demonstrate that the improved ICT affinities are mainly attributed to the superior host–guest size fit arising from the compressed binding cavity in m‐EtLP6 as compared with p‐EtLP6.
A cavity compressing strategy is proposed to modulate the macrocyclic host–guest charge‐transfer (CT) interactions. The solid‐state CT affinities of perethylated leaning pillar6arene toward various electron‐deficient planar guests could be significantly enhanced by transforming the macrocyclic backbone from the original para‐bridged mode into a hybrid para‐ and meta‐bridged isomeric form.
We report new Gaussian boson sampling experiments with pseudo-photon-number-resolving detection, which register up to 255 photon-click events. We consider partial photon distinguishability and ...develop a more complete model for the characterization of the noisy Gaussian boson sampling. In the quantum computational advantage regime, we use Bayesian tests and correlation function analysis to validate the samples against all current classical spoofing mockups. Estimating with the best classical algorithms to date, generating a single ideal sample from the same distribution on the supercomputer Frontier would take ∼600 yr using exact methods, whereas our quantum computer, Jiǔzhāng 3.0, takes only 1.27 μs to produce a sample. Generating the hardest sample from the experiment using an exact algorithm would take Frontier∼3.1×10^{10} yr.
The TianQin-1 satellite (TQ-1), which is the first technology demonstration satellite for the TianQin project, was launched on 20 December 2019. The first round of experiment had been carried out ...from 21 December 2019 until 1 April 2020. The residual acceleration of the satellite is found to be about 1 × 10−10 m/s2/Hz1/2 at 0.1 Hz and about 5 × 10−11 m/s2/Hz1/2 at 0.05 Hz, measured by an inertial sensor with a sensitivity of 5 × 10−12 m/s2/Hz1/2 at 0.1 Hz. The micro-Newton thrusters has demonstrated a thrust resolution of 0.1 μN and a thrust noise of 0.3 μN/Hz1/2 at 0.1 Hz. The residual noise of the satellite with drag-free control is 3 × 10−9 m/s2/Hz1/2 at 0.1 Hz. The noise level of the optical readout system is about 30 pm/Hz1/2 at 0.1 Hz. The temperature stability at temperature monitoring position is controlled to be about ±3 mK per orbit, and the mismatch between the center-of-mass of the satellite and that of the test mass is measured with a precision of better than 0.1 mm.
The study of aqueous-phase molecular recognition of artificial receptors is one of the frontiers in supramolecular chemistry since most biochemical processes and reactions take place in an aqueous ...medium and heavily rely on it. In this work, a water-soluble version of leggero pillar5arene bearing eight positively charged pyridinium moieties (CWP5L) was designed and synthesized, which exhibited good binding affinities with certain aliphatic sulfonate species in aqueous solutions. Significantly, control experiments demonstrate that the guest binding performance of CWP5L is superior to its counterpart water-soluble macrocyclic receptor in traditional pillararenes.
Obesity causes many reproductive dysfunctions such as reduced conception, infertility, and early pregnancy loss, and this is largely due to the negative effects of obesity on oocyte and embryo ...quality. In the present study, we employed single‐cell RNA transcriptome sequencing to investigate the potential causes for the maternal obesity effects on mouse embryos. Our results showed that the 4‐cell and morula/blastocyst rates were all significantly decreased during embryo development in obese mice. Genome‐wide analysis indicated that obesity altered the expression of more than 1100 genes in 2‐cell embryos, including the genes which were related to the p53 signaling pathway and apoptosis. Further analysis showed that the expression of 47 genes related to DNA damage was changed, and a positive γH2A signal and the altered expression of Rad51 and Tex15 were observed in the obese embryos. Obesity also affected histone methylation, shown by the decrease of the H3K4‐me2 level. Besides this, we observed the occurrence of autophagy and apoptosis in the embryos of obese mice. There were 42 genes that were related to autophagy/apoptosis that showed aberrant expression, and the positive LC3 signal and the decrease of Clec16a, Rraga, and Atg10 level were also observed. In summary, our study suggested that obesity affected early embryonic development by inducing DNA damage, aberrant histone methylation, and autophagy levels in mice.
Our results indicate that obesity could affect early embryonic development by the induction of DNA damage, alteration of histone methylation, and autophagy level in mice.
PDF
