Silver-Catalyzed Chlorocyclization for the Synthesis of 3-Chloro-2H-chromenes.

A silver-catalyzed chlorocyclization reaction of aryl 3-aryl-2-propyn-1-yl ethers in the presence of NCS under darkness was accomplished, which provides a straightforward and efficient access to 3-chloro-2H-chromenes.

Simultaneous removal of nitrate, lead, and tetracycline by a fixed-biofilm reactor assembled with kapok fiber and sponge iron: Comparative analysis of operating conditions and biotic community.

In recent years, under the condition of lack of carbon source, the presence of composite micro-pollutants make the removal of nitrate seriously damaged, and to find a suitable way to solve this problem is imminent. A fixed-biofilm carrier modified by mixing sponge iron (SI) and kapok fiber (KF) combined with strain Zoogloea sp. FY6 was constructed in this study to get a fixed-biofilm reactor with merit denitrification performance. By adjusting the operation parameters, it can be concluded that when the carbon to nitrogen (C/N) ratio was 1.5, the hydraulic retention time (HRT) was 6.0 h, and the pH was 6.0, the nitrate removal efficiency (NRE) of the fixed-biofilm reactor was up to 95.4% (2.95 mg L-1 h-1). In addition, the fixed-biofilm reactor constructed in this study can remove lead (Pb2+) and tetracycline (TC) excellently in the presence of SI and Zoogloea sp. FY6, and the denitrification performance can still maintain a high level under the influence of different concentrations of Pb2+ and TC. Furthermore, the addition of SI not only removes the compound pollutants, but also protects the toxicity of the pollutant inflow in the bioreactor, and the metabolic process of microorganisms in the bioreactor also removes some of the compound pollutants. The high-throughput data showed the abundance of strain Zoogloea sp. FY6 was still the highest value under the influence of various pollutants, and the metagenomic prediction showed that the fixed-biofilm reactor had perfect denitrification process and iron redox cycle benefits. This study provides a valuable reference for sustainable utilization of natural biological resources and reduction of material costs in wastewater treatment plants (WWTPs).

Identification of the Metabolites of Both Formononetin in Rat Hepatic S9 and Ononin in Rat Urine Samples and Preliminary Network Pharmacology Evaluation of Their Main Metabolites.

Astragalus membranaceus is a traditional Chinese medicine derived from the roots of Astragalus membranaceus (Fisch.) Bge., which has the same medicinal and edible uses in China. It is also widely used in daily food, and its pharmacological effects mainly include antioxidant effects, vascular softening effects, etc. Currently, it is increasingly widely used in the prevention of hypertension, cerebral ischemia, and stroke in China. Formononetin and its glucopyranoside (ononin) are both important components of Astragalus membranaceuss and may play important roles in the treatment of cardiovascular diseases (CVDs). This study conducted metabolic studies using formononectin and its glucopyranoside (ononin), including a combination of the in vitro metabolism of Formonetin using rat liver S9 and the in vivo metabolism of ononin administered orally to rats. Five metabolites (Sm2, 7, 9, 10, and 12) were obtained from the solution incubated with formononetin and rat hepatic S9 fraction using chromatographic methods. The structures of the five metabolites were elucidated as (Sm2)6,7,4'-trihydroxy-isoflavonoid; (Sm7)7,4'-dihydroxy-isoflavonoid; (Sm9)7,8,4'-trihydroxy-isoflavonoid; (Sm10)7,8,-dihydroxy-4'-methoxy-isoflavonoid; and (Sm12)6,7-dihydroxy-4'-methoxy- isoflavonoid on the basis of UV, NMR, and MS data. Totally, 14 metabolites were identified via HPLC-DAD-ESI-IT-TOF-MSn analysis, from which the formononetin was incubated with rat hepatic S9 fraction, and the main metabolic pathways were hydroxylation, demethylation, and glycosylation. Then, 21 metabolites were identified via HPLC-DAD-ESI-IT-TOF-MSn analysis from the urine samples from SD rats to which ononin was orally administered, and the main metabolic pathways were glucuronidation, hydroxylation, demethylation, and sulfonation. The main difference between the in vitro metabolism of formononetin and the in vivo metabolism of ononin is that ononin undergoes deglycemic transformation into Formonetin in the rat intestine, while Formonetin is absorbed into the bloodstream for metabolism, and the metabolic products also produce combined metabolites during in vivo metabolism. The six metabolites obtained from the aforementioned separation indicate the primary forms of formononetin metabolism, and due to their higher contents of similar isoflavone metabolites, they are considered the main active compounds that are responsible for pharmacological effects. To investigate the metabolites of the active ingredients of formononetin in the rat liver S9 system, network pharmacology was used to evaluate the cardiovascular disease (CVD) activities of the six primary metabolites that were structurally identified. Additionally, the macromolecular docking results of six main components and two core targets (HSP90AA1 and SRC) related to CVD showed that formononetin and its main metabolites, Sm10 and Sm12, may have roles in CVD treatment due to their strong binding activities with the HSP90AA1 receptor, while the Sm7 metabolite may have a role in CVD treatment due to its strong binding activity with the SRC receptor.

Bayesian Model Averaging as an Alternative to Model Selection for Multilevel Models.

We investigated the Bayesian model averaging (BMA) technique as an alternative method to the traditional model selection approaches for multilevel models (MLMs). BMA synthesizes the information derived from all possible models and comes up with a weighted estimate. A simulation study compared BMA with additional modeling techniques, including the single "best" model approach, Bayesian MLM using informative, diffuse, and inaccurate priors, and restricted maximum likelihood. A two-level random intercept and random slope model was examined with these modeling techniques. Generated data used two types of true models: a full MLM and a reduced MLM. Findings of the simulation study suggested that BMA was a trustworthy alternative to traditional model comparison and selection approaches through the Bayesian and the frequentist frameworks. We also include an empirical example highlighting the extension of MLMs into the BMA framework, as well as model interpretation.

Synthesis of Indolizines via Palladium Catalyzed Annulation of Propargyl Carbonates and 2-(Pyridin-2-yl)acetonitrile Derivatives.

A Pd-catalyzed regioselective annulation reaction of propargyl carbonates and 2-(pyridine-2-yl) acetonitrile derivatives has been accomplished, which provides a straightforward and efficient access to polysubstituted indolizines. The choice of the phosphine ligand is crucial to the high regio-selectivity of the reaction.

Synthesis of Allenes by Catalytic Coupling of Propargyl Carbonates with Aryl Iodides in the Presence of Diboron Species.

Bimetallic copper-/palladium-catalyzed multicomponent reaction of propargyl carbonates, aryl iodides, and diboron species was studied. This procedure can be used for synthesis of di-, tri-, and tetra-substituted allenes. Using diboronic acid, the reaction is supposed to proceed via allenylboronic acid intermediate.

Borylation of propargylic substrates by bimetallic catalysis. Synthesis of allenyl, propargylic, and butadienyl Bpin derivatives.

Bimetallic Pd/Cu and Pd/Ag catalytic systems were used for borylation of propargylic alcohol derivatives. The substrate scope includes even terminal alkynes. The reactions proceed stererospecifically with formal SN2' pathways to give allenyl boronates. Opening of propargyl epoxides leads to 1,2-diborylated butadienes probably via en allenylboronate intermediate.

Employing racemization strategies to simultaneously enhance the quantum yield, lifetime, and water stability of room-temperature phosphorescent materials.

Room temperature phosphorescence (RTP) materials are increasingly recognized for their superior luminescent properties, which are pivotal in applications such as anti-counterfeiting, information storage, and optoelectronics. Despite this, the sensitivity of most RTP systems to humidity presents a significant challenge in achieving durable RTP performance in aqueous environments. This study proposes a strategy to enhance organic room-temperature phosphorescence through racemization. By incorporating external racemates of various chiral phosphors-NDBD-Ph, NDBD-Ph-Ph, NDBD-CH3, and NDBD-O-CH3-into a polyacrylonitrile (PAN) matrix, we significantly enhance the RTP properties (quantum yield, lifetime, and afterglow-time) of the resultant films. This enhancement can be attributed to the increased density of racemic molecules in the matrix and the increased spin-orbit coupling (SOC), facilitating the development of a long-lasting polymer RTP system in water. Notably, the racemic rac-NDBD-Ph@PAN film exhibits a persistent bright turquoise afterglow, even after immersion in water for a month. Furthermore, for the first time, we achieved an enhanced green to cyan RTP response to pH variations under both acidic and alkaline conditions (pH = 2-12), with the maximum phosphorescence emission intensity increasing up to threefold. The remarkable water stability, reversible response characteristics, and enhanced phosphorescence properties of this system offer promising potential for dynamic information encryption in aqueous environments.

Finite element analysis of sagittal angles of unicompartmental knee arthroplasty.

BACKGROUND: Unicompartmental knee arthroplasty is an effective treatment for knee osteoarthritis, but it has the risk of failure, and the installation position of the prosthesis is one of the factors affecting the failure. There are few biomechanical studies on the installation angle of unicompartmental knee prosthesis. METHODS: Constructed a finite element model of a normal human knee joint, and the validity of the model was verified by stress and front anterior methods. The mobile-bearing unicompartmental knee arthroplasty femoral prosthesis was placed at 3° intervals from 0° sagittal plane to 15° flexion, and - 2° and 17°were established, and observing the biomechanical changes of components. FINDINGS: Maximum peak stresses occurred at a sagittal mounting angle of -2° for the insert and the contralateral meniscus, with the tibia showing a maximum at 17° sagittal and the tibial prosthesis stress maximum occurring at 6° sagittal. As the sagittal plane angle of the femoral prosthesis increases and the osteotomy distance extends posteriorly, more bone is amputated during the osteotomy. The ratio of the distance from the tip of the anterior intramedullary nail to the anterior end of the osteotomy to the total anteroposterior length of the sagittal osteotomy ranged from 43.2% to 44.6%. INTERPRETATION: In this paper, the more appropriate sagittal mounting position for the femoral prosthesis is between 9 and 12°, based on the amount of osteotomy and the peak stress of each component in a standing position.

Recycling of manganese ore desulfurization slag for preparation of low-temperature NH3-SCR catalyst with good scale-up production performance.

Considering the synergistic carbon/pollution reduction and resource utilization, this study proposes recycling of manganese desulfurization slag to prepare low-temperature NH3 -SCR catalyst based on solid-state ion-exchange. The desulfurization slag was hydrothermally treated to be support under mild conditions, with the parent manganese oxide ore serving as active component. Hydrothermal treatment with a desulfurization slag to NaOH mass ratio of 1.0, at 100 °C for 10 h were actually cost-effective conditions for DS recycling. The catalyst with 13.6 wt% of Mn and activated at 450 °C for 2 h in air (MO3/DSH-450 -2) performed the best, with a NO conversion of 86.9% at 150 °C and 10000 h-1, and up to 92.6% at 175 °C. Hydrothermal treatment of DS, SSIE and calcination activation resulting in a rich surface acidity and lattice oxygen of MO3/DSH, coupled with better chemical state distribution of active metal sites, promoting the NH3 -SCR activity. The scale-up produced MO3/DSH-G maintained 90.4% NOx conversion at 175 °C, showing good robustness, flexibility, and better sulfur/water resistance. The development of MO3/DSH catalyst may make full use of natural manganese ore, is a typical coupling strategy for carbon-pollutant synergistic emission reduction and resource fully utilize.

Tea Polyphenol Epigallocatechin Gallate Protects Against Nonalcoholic Fatty Liver Disease and Associated Endotoxemia in Rats via Modulating Gut Microbiota Dysbiosis and Alleviating Intestinal Barrier Dysfunction and Related Inflammation.

Nonalcoholic fatty liver disease (NAFLD) is characterized by fat accumulation and inflammation. Epigallocatechin gallate (EGCG) has been proven to be effective against NAFLD, but its hepatoprotective mechanisms based on the "gut microbiota-barrier-liver axis" are still not fully understood. Herein, the results demonstrated that EGCG effectively ameliorated NAFLD phenotypes and metabolic disorders in rats fed a high-fat diet (HFD), and inhibited intestinal barrier dysfunction and inflammation, which is also supported in the experiment of Caco-2 cells. Moreover, EGCG could restore gut microbiota diversity and composition, particularly promoting beneficial microbes, including short-chain fatty acids (SCFAs) producers, such as Lactobacillus, and suppressing Gram-negative bacteria, such as Desulfovibrio. The microbial modulation raised SCFA levels, decreased lipopolysaccharide levels, inhibited the TLR4/NF-κB pathway, and strengthened intestinal barrier function via Nrf2 pathway activation, thereby alleviating liver steatosis and inflammation. Spearman's correlation analysis showed that 24 key OTUs, negatively or positively associated with NAFLD and metabolic disorders, were also reshaped by EGCG. Our results suggested that a combinative improvement of EGCG on gut microbiota dysbiosis, intestinal barrier dysfunction, and inflammation might be a potential therapeutic target for NAFLD.

Nano iron tetroxide-modified rice husk biochar promoted Feammox performance of Klebsiella sp. FC61 and synergistically removed Ni2+ and ciprofloxacin.

The iron reduction coupled with ammonia oxidation process (Feammox) is a biological reaction process associated with the nitrogen cycle that has been discovered in recent years. In this study, the iron-reducing bacterium Klebsiella sp. FC61 was attached by synthesizing nano-loadings of iron tetroxide (nFe3O4) onto rice husk biochar (RBC), and the RBC-nFe3O4 was used as an electron shuttle to participate in the biological iron reduction process of soluble and insoluble Fe3+ to improve the ammonia oxidation efficiency to 81.82%. This acceleration of electron transfer increased the carbon consumption rate and further tuned up the COD removal efficiency to 98.00%. The Feammox could be coupled with iron denitrification for internal nitrogen/iron cycling to reduce the accumulation of nitrate by-products and achieve the recycling of iron. In addition, pollutants such as Ni2+, ciprofloxacin, and formed chelates could be removed by pore adsorption and π-π interactions using bio-iron precipitates produced by iron-reducing bacteria.

Treatment of micro-polluted water with low C/N ratio by immobilized bioreactor using PVA/sintered ores@sponge cube: Performance effects and potential removal pathways.

The widespread use of industrial products containing lead (Pb2+) and tetracycline (TC) medications led to the combined pollution of nitrate, Pb2+, and TC in water. A novel biomaterial containing polyvinyl alcohol (PVA) and sponge cube with sintered ores (PVA/sintered ores@sponge cube) was prepared to ensure the maximum NO3--N removal efficiency (96.21 %) of the bioreactor under the hydraulic retention time (HRT) of 7.0 h, pH of 6.0, and the carbon to nitrogen (C/N) of 1.5 that had the ability to remove TC and Pb2+ synergistically. Composite pollutants slightly decreased denitrification performance in the combined pollution system on account of the addition of sintered ores. Results of scanning electron microscopy (SEM) showed that the sintered ores in the biocarrier induced denitrification and the adsorption of bio­iron oxides were involved in the removal of TC and Pb2+. The simultaneous removal of composite pollutants during denitrification was facilitated by extracellular polymeric substances (EPS) as revealed by Fourier transform infrared spectroscopy (FTIR) and fluorescence excitation-emission matrix (EEM). In addition, high-throughput sequencing results showed that Zoogloea had the highest proportion in the bioreactor.

Disturbance observer-based adaptive position control for a cutterhead anti-torque system.

To conveniently replace worn cutterhead tools in complicated strata, a novel cutterhead attitude control mechanism was recently designed. Meanwhile, the mechanism also causes an engineering problem of how to control a matching cutterhead anti-torque system (CATS) effectively, which is used to prevent a drive box of the cutterhead from rotation during a complex excavation process. In this paper, a disturbance observer-based adaptive position controller is proposed for the CATS. The proposed method presents a nonlinear adaptive controller with adaptation laws to compensate for the unknown time-varying load torque and damping uncertainty in the system. Based on the disturbance observer method and sliding mode control, an asymptotically stable controller proven by Lyapunov theory is constructed using the back-stepping technique. In addition, a virtual test rig based on MATLAB and AMESim co-simulation is built to verify the validity of the proposed controller. The simulation results show that the proposed method has good performance for tracking tasks in the presence of uncertainties compared with PID control. Together, the data support targeting disturbance observer-based adaptive position control as a potential control strategy for cutterhead anti-torque systems.

Simultaneous removal of nitrate, tetracycline, and Pb(II) by iron oxidizing strain Zoogloea sp. FY6: Performance and mechanism.

Based on the prevalence of combined antibiotics and heavy metals contamination in the aquatic environment, this study utilized a microbial approach to achieve simultaneous removal of nitrate (NO3--N), tetracycline (TTC), and Pb(II). Zoogloea sp. FY6 could achieve an optimal NO3--N removal efficiency of 91.5% under C/N ratio of 2.0, at a pH of 6.3, and Fe(II) concentration of 20.23 mg L-1 based on response surface methodology. Additionally, strain FY6 was further found to achieve 89.9 and 81.7% removal of TTC and Pb(II) at 6 h under the optimal conditions. Finally, the results of Fluorescence excitation-emission matrix, X-ray diffraction, Fourier transform infrared spectrometer, and X-ray photoelectron spectroscopy further proved that the biologically formed nanoscale iron oxides and biological action jointly led to the removal of TTC and Pb(II). This study provided a theoretical basis for the application of microbially driven process to remove multi-pollutants in micro-polluted water bodies.

Magnetite-loaded rice husk biochar promoted the denitrification performance of Aquabacterium sp. XL4 under low carbon to nitrogen ratio: Optimization and mechanism.

The removal of nitrate (NO3--N) under the low carbon to nitrogen (C/N) ratio is a widespread issue. Here in, a modified biochar (MRHB) was prepared by combining rice husk and magnetite to promote the denitrification performance of Aquabacterium sp. XL4 under low C/N ratio. In addition, when the modified H2O2 concentration was 0.6 mM, the dosage was 5.0 g L-1, the C/N ratio was 1.5, and the pH was neutral, the nitrate removal efficiency is 97.9%. Fluorescence excitation-emission matrix spectra (3D-EEM) showed that the metabolism of strain XL4 was stable under optimal conditions. Furthermore, the results of flow cytometry (FC) showed that the amounts of intact cells with MRHB was excellent. The measurement of cytochrome c concentration, total membrane permeability (Tmp), electron transport system activity (ETSA), and cyclic voltammetry curve (CV) confirmed that the MRHB improved the electron transfer and membrane activity of strain XL4.

Denitrification performance of nitrate-dependent ferrous (Fe2+) oxidizing Aquabacterium sp. XL4: Adsorption mechanisms of bio-precipitation of phenol and estradiol.

In this study, a nitrate-dependent ferrous (Fe2+) oxidizing strain under anaerobic conditions was selected and identified as XL4, which belongs to Aquabacterium. The Box-Behnken design (BBD) was used to optimize the growth conditions of strain XL4, and the nitrate removal efficiency of strain XL4 (with 10% inoculation dosage, v/v) could reach 91.41% under the conditions of 30.34 â„ƒ, pH of 6.91, and Fe2+ concentration of 19.69 mg L-1. The results of Fluorescence excitation-emission matrix spectra (EEM) revealed that the intensity of soluble microbial products (SMP), aromatic proteins and the fulvic-like materials were obvious difference under different Fe2+ concentration, pH, and temperature. X-ray diffraction (XRD) data confirmed that the main components of bio-precipitation were Fe3O4 and FeO(OH), which were believed to be responsible for the adsorption of phenol and estradiol. Furthermore, the maximum adsorption capacity of bio-precipitation for phenol and estradiol under the optimal conditions were 192.6 and 65.4 mg g-1, respectively. On the other hand, the adsorption process of phenol and estradiol by bio-precipitation confirmed to the pseudo-second-order and Langmuir model, which shows that the adsorption process is chemical adsorption and occurs on the uniform surface.

Phenol and 17ß-estradiol removal by Zoogloea sp. MFQ7 and in-situ generated biogenic manganese oxides: Performance, kinetics and mechanism.

The pollution of multifarious pollutants such as heavy metal, organic compounds, and nitrate are a hot research topic at present. In this study, the functions of Zoogloea sp. MFQ7 and its biological precipitation formed during bacterial manganese oxidation on the removal of phenol and 17ß-estradiol (E2) were investigated. Strain MFQ7, a manganese-oxidizing bacteria, can remove 98.34% of phenol under pH of 7.1, a temperature of 30 â„ƒ and Mn2+ concentration of 24.34 mg L-1, additionally, the optimum E2 removal by strain MFQ7 was 100.00% at pH of 7.1, temperature of 28 â„ƒ and Mn2+ concentration of 28.45 mg L-1 by using response surface methodology (RSM) based on Box-Behnken design (BBD) model. The maximum adsorption capacity of bio-precipitation for phenol and E2 was 201.15 mg g-1 and 65.90 mg g-1, respectively. Furthermore, adsorption kinetics and isotherms analysis, XPS, FTIR spectra, Mn(III) trapping experiments elucidated chemical adsorption and Mn(III) oxidation contribute to the removal of phenol and E2 by biogenic manganese oxides. These findings indicated that the adsorption and oxidation of manganese are expected to be one of the effective means to remove these typical organic pollutants containing phenol and E2.

Learning Semantic-Aware Local Features for Long Term Visual Localization.

Extracting robust and discriminative local features from images plays a vital role for long term visual localization, whose challenges are mainly caused by the severe appearance differences between matching images due to the day-night illuminations, seasonal changes, and human activities. Existing solutions resort to jointly learning both keypoints and their descriptors in an end-to-end manner, leveraged on large number of annotations of point correspondence which are harvested from the structure from motion and depth estimation algorithms. While these methods show improved performance over non-deep methods or those two-stage deep methods, i.e., detection and then description, they are still struggled to conquer the problems encountered in long term visual localization. Since the intrinsic semantics are invariant to the local appearance changes, this paper proposes to learn semantic-aware local features in order to improve robustness of local feature matching for long term localization. Based on a state of the art CNN architecture for local feature learning, i.e., ASLFeat, this paper leverages on the semantic information from an off-the-shelf semantic segmentation network to learn semantic-aware feature maps. The learned correspondence-aware feature descriptors and semantic features are then merged to form the final feature descriptors, for which the improved feature matching ability has been observed in experiments. In addition, the learned semantics embedded in the features can be further used to filter out noisy keypoints, leading to additional accuracy improvement and faster matching speed. Experiments on two popular long term visual localization benchmarks (Aachen Day and Night v1.1, Robotcar Seasons) and one challenging indoor benchmark (InLoc) demonstrate encouraging improvements of the localization accuracy over its counterpart and other competitive methods.

Denitrification potential of sodium alginate gel beads immobilized iron-carbon, Zoogloea sp. L2, and riboflavin: Performance optimization and mechanism.

A kind of gel beads loaded with iron-carbon powder (Fe-C), Zoogloea sp. L2, and riboflavin (VB2) were prepared through cross-linking of sodium alginate (SA) to establish an immobilized bioreactor. The optimal ratio of SA beads was adjusted by orthogonal experiment. The change of oxidation-reduction potential (ORP) and the concentration of Fe2+ and Fe3+ showed that the addition of VB2 as a redox mediator can promote denitrification. Under the optimal conditions (carbon to nitrogen (C/N) ratio = 2.0, pH = 7.0, and hydraulic retention time (HRT) = 8 h), the nitrate removal efficiency (NRE) of bioreactor reached 98.48% (1.99 mg L-1h-1). Furthermore, Fourier transform infrared spectrometer (FTIR), Fluorescence excitation-emission matrix (EEM), X-ray diffraction (XRD), and gas chromatography (GC) analysis revealed that the immobilization and denitrification of the immobilized bioreactor were excellent. High throughput sequencing also showed that Zoogloea played a vital role in nitrate removal.