Soil conditioning of clay based on interface adhesion mechanism:Microscopic simulation and laboratory experiment

Clogging frequently occurs in the cutter head,excavation chamber or screw conveyor when an earth pressure balance(EPB)shield machine is tunneling in soft or silty clay ground with high clay mineral content.In this paper,montmorillonite,kaolinite,and illite were selected as research objects,and molecular dynamics simulation and laboratory experiment were adopted.At the microscopic scale,dynamic contact behavior and interfacial mechanical behavior of the interface between clay minerals and water/surfactant solution was simulated and the interfacial adhesion and conditioning mechanism between clay minerals and water/surfactant solution was revealed.Thus,sodium dodecyl benzene sulfonate surfactant was selected as the main composition of the soil conditioner.Then,the adhesion stress before and after soil conditioning and the contact angles between clay minerals and water/surfactant solution were tested and analyzed at the macroscopic scale.The result shows that the contact angle between droplet and clay mineral surface is an important parameter to characterize soil adhesion.The simulation rules of the microscopic contact angle are consistent with the experiment results.Furthermore,the adsorption energy between microscopic substances is dominated by electrostatic force,which can reflect the adhesion stress between macroscopic substances.Soil adhesion stress can be effectively decreased by adding the surfactant to the soil conditioner.

Biocatalytic stereoselective synthesis of methyl mandelates by engineering a cytochrome P450 hydroxylase

Chiral methyl mandelates are useful synthons in organic transformation and pharmaceutical synthesis.Green synthesis of these valuable compounds by direct C–H activating oxidative hydroxylation has attracted keen interest.Described herein is achieving the stereoselective and efficient bio-hydroxylation of methyl 2-phenylacetates to the chiral methyl mandelates by directed evolution of the cytochrome P450DA hydroxylase.In the present study,a new colorimetric high-throughput screening assay was successfully developed based on a dualenzyme cascade for the engineering of the P450DA's hydroxylation activity.Several beneficial variants with enhanced bio-hydroxylation activity were created by combining random mutagenesis and site-saturated/directed mutagenesis strategies.Whole-cell bio-hydroxylation of various methyl 2-phenylacetates using the best septupletmutant P450DA-11 yielded the corresponding chiral methyl mandelates in up to 92%isolated yields and>99%ee.

New speckle pattern interferometry for precise in situ deformation measurements

A new electronic speckle pattern interferometry method is proposed to realize in situ deformation measurements.The feature of the method is the combination of a high-speed camera and multiple laser Doppler vibrometers(LDVs)for synchronous measurements.The high-speed camera is used to record and select effective interferograms,while the LDVs are used to measure the rigid body displacement caused by vibrations.A series of effective interferograms with known shifted phase values are obtained to calculate the deformation phase.The experimental results show that the method performs well in measuring static and dynamic deformations with high accuracy in vibrating environments.

Mediating Role of Glucose-Lipid Metabolism in the Association between the Increased Risk of Coronary Heart Disease and Exposure to Organophosphate Esters,Phthalates,and Polycyclic Aromatic Hydrocarbons

There is a lack of human evidence concerning the cardiovascular effects of combined exposure to endocrine disruptors.This case-control study sought to investigate coronary heart disease(CHD)associations with exposure to organophosphate flame retardants(OFRs),phthalates(PAEs),and polycyclic aromatic hydrocarbons(PAHs)among 148 adults with coronary-angiography-diagnosed CHD and 320 healthy adults from southern China.The mediating role of glucose-lipid metabolism was also explored.Bayesian kernel machine regression suggested that when exposure status was fixed to the 75th percentile with the median value as the reference,exposure to OFRs,PAEs,and PAHs was associated with an 84%(95%CI:36%−134%),132%(12%−252%),and 214%(89%−331%)increased risk of developing CHD,respectively.Weighted quantile sum regression indicated urinary bis(2-butoxyethyl)phosphate(BBOEP),dibutyl phosphate(DBP),monoisononyl phthalate(miNP),and metabolites of phenanthrene may be major contributors to the overall effect of mixtures.In further analyses on identified chemical risk factors,mediation analyses suggested exposure to phenanthrene may increase the risk of CHD via elevating total cholesterol and blood glucose,while exposure to DiNP mainly associates with serum lipids.Besides,we observed a slight mediation effect of oxidative DNA damage between urinary BBOEP and risk of CHD.These results provide potential direction for further experimental studies.Longitudinal evidence is needed to clarify the causation of the results.

Inositol Pyrophosphate lnsP8 Acts as an Intracellular Phosphate Signal in Arabidopsis

The maintenance of cellular phosphate(Pi)homeostasis is of great importance in living organisms.The SPX domain-containing protein 1(SPX1)proteins from both Arabidopsis and rice have been proposed to act as sensors of Pi status.The molecular signal indicating the cellular Pi status and regulating Pi homeostasis in plants,however,remains to be identified,as Pi itself does not bind to the SPX domain.Here,we report the identification of the inositol pyrophosphate lnsP8 as a signaling molecule that regulates Pi homeostasis in Arabidopsis.Polyacrylamide gel electrophoresis profiling of InsPs revealed that lnsP8 level positively cor­relates with cellular Pi concentration.We demonstrated that the homologs of diphosphoinositol pentaki-sphosphate kinase(PPIP5K),VIH1 and VIH2,function redundantly to synthesize lnsP8,and that the vih1 vih2 double mutant overaccumulates Pi.SPX1 directly interacts with PHR1,the central regulator of Pi star­vation responses,to inhibit its function under Pi-replete conditions.However,this interaction is compro­mised in the vih1 vih2 double mutant,resulting in the constitutive induction of Pi starvation-induced genes,indicating that plant cells cannot sense cellular Pi status without lnsP8.Furthermore,we showed that lnsP8 could directly bind to the SPX domain of SPX1 and is essential for the interaction between SPX1 and PHR1.Collectively,our study suggests that lnsP8 is the intracellular Pi signaling molecule serving as the ligand of SPX1 for controlling Pi homeostasis in plants.

Emerging Evidence Linking the Liver to the Cardiovascular System: Liver-derived Secretory Factors

Cardiovascular diseases(CVDs)remain the leading cause of morbidity and mortality worldwide.Recently,accumulating evidence has revealed hepatic mediators,termed as liverderived secretory factors(LDSFs),play an important role in regulating CVDs such as atherosclerosis,coronary artery disease,thrombosis,myocardial infarction,heart failure,metabolic cardiomyopathy,arterial hypertension,and pulmonary hypertension.LDSFs presented here consisted of microbial metabolite,extracellular vesicles,proteins,and microRNA,they are primarily or exclusively synthesized and released by the liver,and have been shown to exert pleiotropic actions on cardiovascular system.LDSFs mainly target vascular endothelial cell,vascular smooth muscle cells,cardiomyocytes,fibroblasts,macrophages and platelets,and further modulate endothelial nitric oxide synthase/nitric oxide,endothelial function,energy metabolism,inflammation,oxidative stress,and dystrophic calcification.Although some LDSFs are known to be detrimental/beneficial,controversial findings were also reported for many.Therefore,more studies are required to further explore the causal relationships between LDSFs and CVDs and uncover the exact mechanisms,which is expected to extend our understanding of the crosstalk between the liver and cardiovascular system and identify potential therapeutic targets.Furthermore,in the case of patients with liver disease,awareness should be given to the implications of these abnormalities in the cardiovascular system.These studies also underline the importance of early recognition and intervention of liver abnormalities in the practice of cardiovascular care,and a multidisciplinary approach combining hepatologists and cardiologists would be more preferable for such patients.

The chromatin remodeler BRAHMA recruits HISTONE DEACETYLASE6 to regulate root growth inhibition in response to phosphate starvation in Arabidopsis

Plasticity in root system architecture(RSA)allows plants to adapt to changing nutritional status in the soil.Phosphorus availability is a major determinant of crop yield,and RSA remodeling is critical to increasing the efficiency of phosphorus acquisition.Although substantial progress has been made in understanding the signaling mechanism driving phosphate starvation responses in plants,whether and how epigenetic regulatory mechanisms contribute is poorly understood.Here,we report that the Switch defective/sucrose non-fermentable(SWI/SNF)ATPase BRAHMA(BRM)is involved in the local response to phosphate(Pi)starvation.The loss of BRM function induces iron(Fe)accumulation through increased LOW PHOSPHATE ROOT1(LPR1)and LPR2 expression,reducing primary root length under Pi deficiency.We also demonstrate that BRM recruits the histone deacetylase(HDA)complex HDA6-HDC1 to facilitate histone H3 deacetylation at LPR loci,thereby negatively regulating local Pi deficiency responses.BRM is degraded under Pi deficiency conditions through the 26 S proteasome pathway,leading to increased histone H3 acetylation at the LPR loci.Collectively,our data suggest that the chromatin remodeler BRM,in concert with HDA6,negatively regulates Fe-dependent local Pi starvation responses by transcriptionally repressing the RSA-related genes LPR1 and LPR2 in Arabidopsis thaliana.

Fluorescent and colorimetric immunoassay of nuclear matrix protein 22 enhanced by porous Pd nanoparticles

A modified ELISA realizing fluorescent and colorimetric immunoassay of nuclear matrix protein 22 (NMP 22) was developed based on porous Pd nanoparticles. The unique structure and excellent enzyme mimetic activity of porous Pd nanoparticles favor to oxidize o-phenylenediamine (OPD) into 2,3-phenazinediamine (oxOPD) by H2O2, producing colorimetric and fluorescence dual-readout signal for the detection of NMP 22. The developed immunoassay method will offer great potential in clinical research and diagnostic applications.