Metagenomic analysis reveals the mechanisms of biochar supported nano zero-valent iron in two-phase anaerobic digestion of food waste: microbial community, CAZmey, functional genes and antibiotic resistance genes.

The mechanisms of biochar supported nano zero-valent iron (BC/nZVI) on two-phase anaerobic digestion of food waste were investigated. Results indicated that the performance of both acidogenic phase and methanogenic phase was effectively facilitated. BC/nZVI with the amount of 120 mg/L increased methane production by 32.21%. In addition, BC/nZVI facilitated direct interspecies electron transfer (DIET) between Geobacter and methanogens. Further analysis showed that BC/nZVI increased the abundance of most CAZymes in acidogenic phase. The study also found that BC/nZVI had positive effects on metabolic pathways and related functional genes. The abundances of acdA and ackA in acidogenic phase were increased by 151.75% and 36.26%, respectively, and the abundances of pilA and TorZ associated with DIET were also increased. Furthermore, BC/nZVI mainly removed IMP-12, CAU-1, cmeB, ErmR, MexW, ErmG, Bla2, vgaD, MuxA, and cpxA from this system, and reduced the antibiotic resistance genes for antibiotic inactivation resistance mechanisms.

Aqueous-Aqueous Triboelectric Nanogenerators Empowered Multifunctional Wound Healing System with Intensified Current Output for Accelerating Infected Wound Repair.

Triboelectric nanogenerators (TENGs) have emerged as promising devices for generating self-powered therapeutic electrical stimulation over multiple aspects of wound healing. However, the challenge of achieving full 100% contact in conventional TENGs presents a substantial hurdle in the quest for higher current output, which is crucial for further improving healing efficacy. Here, a novel multifunctional wound healing system is presented by integrating the aqueous-aqueous triboelectric nanogenerators (A-A TENGs) with a functionalized conductive hydrogel, aimed at advancing infected wound therapy. The A-A TENGs are founded on a principle of 100% contact interface and efficient post-contact separation of the immiscible interface within the aqueous two-phase system (ATPS), enhancing charge transfer and subsequently increasing current performance. Leveraging this intensified current output, this system demonstrates efficient therapeutic efficacies over infected wounds both in vitro and in vivo, including stimulating fibroblast migration and proliferation, boosting angiogenesis, enhancing collagen deposition, eradicating bacteria, and reducing inflammatory cells. Moreover, the conductive hydrogel ensures the uniformity and integrity of the electric field covering the wound site, and exhibits multiple synergistic therapeutic effects. With the capability to realize accelerated wound healing, the developed "A-A TENGs empowered multifunctional wound healing system" presenting an excellent prospect in clinical wound therapy.

Continuous Sampling of Aerosolized Particles Using Stratified Two-Phase Microfluidics.

Health and security concerns have made it essential to develop integrated, continuous collection and sensing platforms that are compact and capable of real-time detection. In this study, we numerically investigate the flow physics associated with the single-step collection and enrichment of aerosolized polystyrene microparticles into a flowing liquid using a stratified air-water flow in a U-shaped microchannel. We validate our simulation results by comparing them to experimental data from the literature. Additionally, we fabricate an identical microfluidic device using PDMS-based soft lithography and test it to corroborate the previously published experimental data. Diversion and entrapment efficiencies are used as evaluation metrics, both of which increase with increasing particle diameter and superficial air inlet velocity. Overall, our ANSYS Fluent two-dimensional (2D) and three-dimensional (3D) multiphase flow simulations exhibit a good agreement with our experimental data and data in the literature (average deviation of ∼11%) in terms of diversion efficiency. Simulations also found the entrapment efficiency to be lower than the diversion efficiency, indicating discrepancies in the literature in terms of captured particles. The effect of the Dean force on the flow physics was also investigated using 3D simulations. We found that the effect of the Dean flow was more dominant relative to the centrifugal force on the smaller particles (e.g., 0.65 µm) compared to the larger particles (e.g., 2.1 µm). Increasing the superficial air inlet velocity also increases the effect of the centrifugal forces relative to the Dean forces. Overall, this experimentally validated multiphase model decouples and investigates the multiple and simultaneous forces on aerosolized particles flowing through a curved microchannel, which is crucial for designing more efficient capture devices. Once integrated with a microfluidic-based biosensor, this stratified flow-based microfluidic biothreat capture platform should deliver continuous sensor-ready enriched biosamples for real-time sensing.

Two-Phase Particle Image Velocimetry Visualization of Rewetting Flow on the Micropillar Interfacial Surface.

Boiling heat transfer has a high thermal efficiency by latent heat absorption, which makes it an attractive process for cooling electronic device chips. Critical heat flux (CHF), the maximum heat flux, is a crucial factor determining the operating range of the boiling applications. The CHF can be enhanced by improving the fluid supply to the boiling surface. Herein, micropillar interfacial surfaces have been proposed to increase the CHF by increasing the rewetting flow, which determines the fluid-supply capacity near the bubble contact line. A state-of-art two-phase particle image velocimetry (two-phase PIV) technique is introduced for rewetting flow measurement on micropillar structures (MPSs) to analyze the CHF-enhancement mechanism. The two-phase PIV visualization setup offers high spatial (∼120 µm) and temporal (∼2000 Hz) resolutions for measuring rewetting flow during bubble growth. The MPS samples exhibit enhanced CHF and rewetting flows compared to those on a plain surface. The roughest case, D04G10 sample, had a CHF of 164 W/cm2, 1.84 times higher than that of the plain surface. The D04G10 sample also recorded the highest rewetting velocity of 0.311 m/s, 4.7 times higher than that of the plain surface. The comparison between the rewetting flow and wicking performance shows that wicking-induced flow accounted for a substantial part (∼17%) of the rewetting flow and contributed significantly to the CHF enhancement owing to large rewetting flow by delaying vapor-film formation. Based on these findings, a new CHF model suggested by introducing the rewetting parameter shows a high CHF prediction accuracy of 94%.

What Can Be Learned from the Partitioning Behavior of Proteins in Aqueous Two-Phase Systems?

This review covers the analytical applications of protein partitioning in aqueous two-phase systems (ATPSs). We review the advancements in the analytical application of protein partitioning in ATPSs that have been achieved over the last two decades. Multiple examples of different applications, such as the quality control of recombinant proteins, analysis of protein misfolding, characterization of structural changes as small as a single-point mutation, conformational changes upon binding of different ligands, detection of protein-protein interactions, and analysis of structurally different isoforms of a protein are presented. The new approach to discovering new drugs for a known target (e.g., a receptor) is described when one or more previous drugs are already available with well-characterized biological efficacy profiles.

Precipitation and evaporation affecting landfill gas migration into passive methane oxidation biosystems: Models development and verification.

Passive methane oxidation biosystems (PMOBs) are developed as an innovative and cost-effective solution to reduce methane (CH4) emissions from municipal solid waste landfills. A PMOB consists of a methane oxidation layer (MOL) and an underlying gas distribution layer (GDL). The length of unrestricted gas migration (LUGM) has been recently proposed as the design criterion for PMOBs where the LUGM is calculated as the horizontal length along the MOL-GDL interface with the volumetric gas content (θa) exceeding the threshold volumetric gas content (θa,occ). This paper examined water and gas migration within three PMOBs with different MOL-GDL interfaces subject to precipitation and evaporation using verified numerical models. The results show that the use of a single-phase flow model underestimates the LUGM values of the PMOB for heavy precipitation events, and a two-phase flow model should be used to calculate both the LUGM and the total gas mass flow rate into the MOL when designing PMOBs. Both zig-zag and trapezoidal MOL-GDL interfaces can redistribute the gas mass flow rate at the MOL-GDL interface, while the trapezoidal MOL-GDL interface slightly outperforms the zig-zag MOL-GDL interface for enhancing the total gas mass flow rate into the MOL when comparing with the planar MOL-GDL interface. The zig-zag and trapezoidal MOL-GDL interfaces allow gas migration in the upper part of each PMOB segment even when the lower part of each PMOB segment was filled with water, and thus have a potential to minimize hotspot formation.

An Automated Gradient Titration Fluorescence Methodology for High-Resolution Identification of Aqueous Two-Polymer Phase Extraction Conditions for Single-Wall Carbon Nanotubes.

A significant advance in rate and precision of identifying the co-surfactant concentrations leading to differential extraction of specific single-wall carbon nanotube (SWCNT) species in aqueous two-polymer phase extraction experiments is reported. These gains are achieved through continuous titration of co-surfactant and other solution components during automated fluorescence measurements on SWCNT dispersions. The resulting fluorescence versus concentration curves display intensity and wavelength shift transitions traceable to the nature of the adsorbed surfactant layer on specific SWCNT structures at the (n,m) species and enantiomer level at high resolution. The increased precision and speed of the titration method resolve previously invisible complexity in the SWCNT fluorescence during the transition from one surfactant dominating the SWCNT interface to the other, offering insight into the fine details of the competitive exchange process. For the first time, we additionally demonstrate that the competitive process of the surfactant switch is direction independent (reversible) and hysteresis-free; the latter data effectively specifies an upper bound for the time scale of the exchange process. Titration curves are compared to literature results and initial advanced parameter variation is conducted for previously unreasonable to investigate solution conditions.

Optimization of sulfate reduction and methanogenesis via phase separation in a two-phase internal circulation reactor for the treatment of high-sulfate organic wastewater.

To enhance the performance of the internal circulation (IC) reactor when treating high-sulfate organic wastewater, a laboratory-scale two-phase IC reactor with distinct phase separation capabilities was designed, and the sulfate reduction and methanogenesis processes were optimized by segregating the reactor into two specialized reaction zones. The results demonstrated that the first and second reaction areas of the two-phase IC reactor could be maintained at 4.5-6.0 and 7.5-8.5, respectively, turning them into the specialized phase for sulfate reduction and methanogenesis. Through phase separation, the two-phase IC reactor achieved a COD degradation and sulfate reduction efficiency of more than 80% when the influent sulfate concentration exceeded 5,000 mg/L, which were 32.32% and 16.04% higher than that before phase separation. Functional analyses indicated a greater activity of both the dissimilatory and assimilatory sulfate reduction pathways in the acidogenic phase, largely due to a rise in the relative abundance of the genera Desulfovibrio, Bacteroides, and Lacticaseibacillus, the primary carriers of sulfate reduction functional genes. In contrast, all the acetoclastic, hydrogenotrophic, and methylotrophic methanogenesis pathways were inhibited in the acidogenic phase but thrived in the methanogenic phase, coinciding with shifts in the genus Methanothrix, which harbors the mcrA, mcrB, and mcrG genes essential for the final transformation step of all three methanogenesis pathways.

Exploring UAS-lidar as a sampling tool for satellite-based AGB estimations in the Miombo woodland of Zambia.

To date, only a limited number of studies have utilized remote sensing imagery to estimate aboveground biomass (AGB) in the Miombo ecoregion using wall-to-wall medium resolution optical satellite imagery (Sentinel-2 and Landsat), localized airborne light detection and ranging (lidar), or localized unmanned aerial systems (UAS) images. On the one hand, the optical satellite imagery is suitable for wall-to-wall coverage, but the AGB estimates based on such imagery lack precision for local or stand-level sustainable forest management and international reporting mechanisms. On the other hand, the AGB estimates based on airborne lidar and UAS imagery have the precision required for sustainable forest management at a local level and international reporting requirements but lack capacity for wall-to-wall coverage. Therefore, the main aim of this study was to investigate the use of UAS-lidar as a sampling tool for satellite-based AGB estimation in the Miombo woodlands of Zambia. In order to bridge the spatial data gap, this study employed a two-phase sampling approach, utilizing Sentinel-2 imagery, partial-coverage UAS-lidar data, and field plot data to estimate AGB in the 8094-hectare Miengwe Forest, Miombo Woodlands, Zambia, where UAS-lidar estimated AGB was used as reference data for estimating AGB using Sentinel-2 image metrics. The findings showed that utilizing UAS-lidar as reference data for predicting AGB using Sentinel-2 image metrics yielded superior results (Adj-R2 = 0.70, RMSE = 27.97) than using direct field estimated AGB and Sentinel-2 image metrics (R2 = 0.55, RMSE = 38.10). The quality of AGB estimates obtained from this approach, coupled with the ongoing advancement and cost-cutting of UAS-lidar technology as well as the continuous availability of wall-to-wall optical imagery such as Sentinel-2, provides much-needed direction for future forest structural attribute estimation for efficient management of the Miombo woodlands.

A two-phase flow model simulating water penetration into pharmaceutical tablets.

The purpose of the study is introduce a two-phase flow model to simulate water penetration into pharmaceutical tablets. This model was built by integrating Darcy's law with the continuity principle, on the premise that water penetration was driven by capillary actions. Notably, this model concerned both the ingress of water (wetting phase) and simultaneous displacement of air (non-wetting phase). Due to the interference of the two fluids, the relative permeability and capillary pressure vary during water penetration. Evolution of these parameters was incorporated in the model. Calibration of the model by water penetration experiments of the microcrystalline cellulose (MCC) tablet yielded an average pore radius of 42 nm. This derived result was corroborated by FIB-SEM analysis revealing the presence of extensive microporosity within MCC particles with an average radius of ∼30 nm. Further validation was achieved through close resemblance between the simulated and experimental water penetration profiles of MCC tablets possessing different porosities. Overall, this study underscored the advantage of the two-phase flow model over single-phase flow models, by capturing the dependence of permeability and capillary pressure on water saturation. Therefore it holds promise for an enhanced description of water penetration into tablets.

Optimal two-phase sampling for comparing correlated areas under the ROC curves of two screening tests in the presence of verification bias.

The accuracy of a screening test is often measured by the area under the receiver characteristic (ROC) curve (AUC) of a screening test. Two-phase designs have been widely used in diagnostic studies for estimating one single AUC and comparing two AUCs where the screening test results are measured for a large sample (Phase one sample) while the disease status is only verified for a subset of Phase one sample (Phase two sample) by a gold standard. In this paper, we consider the optimal two-phase sampling design for comparing the performance of two ordinal screening tests in classifying disease status. Specifically, we derive an analytical variance formula for the AUC difference estimator and use it to find the optimal sampling probabilities that minimize the variance formula for the AUC difference estimator. According to the proposed optimal two-phase design, the strata with the levels of two tests far apart from each other should be over-sampled while the strata with the levels of two tests close to each other should be under-sampled. Simulation results indicate that two-phase sampling under optimal allocation (OA) achieves a substantial amount of variance reduction, compared with two-phase sampling under proportional allocation (PA). Furthermore, in comparison with a one-phase random sampling, two-phase sampling under OA or PA has a clear advantage in reducing the variance of AUC difference estimator when the variances of the two screening test results in the disease population differ greatly from their counterparts in non-disease population.

MHD Maxwell dusty fluid in thermally stratified radiative flow with temperature-dependent thermal conductivity and Cattaneo-Christov model.

It might be very important for the polymer processing industries to comprehend how Maxwell fluids behave on a stretched cylinder. Optimizing the extrusion and drawing processes can ensure the desired product qualities while avoiding faults. The objective of this study is heat transfer analysis on a Maxwell dusty fluid flow cylindrical surface with the Cattaneo-Christov concept. We immerse the cylinder in porous media, with a two-dimensional fluid regulating the flow. Our mathematical model further considers the effects of variable thermal conductivity, radiation, viscous and joule heating, magnetic field, thermal stratification, and slip velocity. Based on the presumptions, partial differential equations (PDE's) have been used to evolve the mathematical model. Using similarity transformations, the PDE's for heat and momentum for both phases are transformed into highly nonlinear ODE's.The numerical results have been obtained on these ordinary differential equations by using the RKF-45 method. This issue's main characteristic is that it examines the scenario's liquid and dust phases throughout. Results are given both visually and tabularly for the major parameters over a velocity, temperature, skin friction coefficient, and Nusselt number. When we compared our method to a previously published paper, we discovered a decent match. The findings, which were obtained for our system, show that the velocity and thermal gradient of both the phases of fluid and dust behave in an opposite trend in favor of rising Maxwell parameter, where the curvature parameter makes the rise in the same manner. Furthermore, the thermal transport profiles for both phases decline for the rising thermal time relaxation parameter.

2D and 3D Self-Assembly of Fluorine-Free Pillar-[5]-Arenes and Perfluorinated Diacids at All-Aqueous Interfaces.

The interaction of perfluorinated molecules, also known as "forever chemicals" due to their pervasiveness, with their environment remains an important yet poorly understood topic. In this work, the self-assembly of perfluorinated molecules with multivalent hosts, pillar-[5]-arenes, is investigated. It is found that perfluoroalkyl diacids and pillar-[5]-arenes rapidly and strongly complex with each other at aqueous interfaces, forming solid interfacially templated films. Their complexation is shown to be driven primarily by fluorophilic aggregation and assisted by electrostatic interactions, as supported by the crystal structure of the complexes, and leads to the formation of quasi-2D phase-separated films. This self-assembly process can be further manipulated using aqueous two-phase system microdroplets, enabling the controlled formation of 3D micro-scaffolds.

Magnetic levitation system control based on a novel tracking differentiator.

This study proposes a novel tracking differentiator and applies it to the sliding-mode control (SMC) algorithm to address the unsatisfactory disturbance suppression and low tracking accuracy of magnetic levitation (maglev) systems. First, to assess performance in terms of filtering, tracking, and differentiation, an inverse hyperbolic sine function and a two-phase power function are introduced to improve the tracking differentiator. This can accelerate the global convergence speed, ensure smooth convergence at the equilibrium point, reduce system jitter, and enhance the noise-suppression ability of the system. The differentiator parameter-adjustment rules are derived from a system sweep. A comparison of the simulation results show that the proposed differentiator effectively suppresses noise and performs signal tracking and differentiation. Finally, the new differentiator is applied to the SMC of a maglev system. Simulation and experimental results show that the response speed of the maglev system under the SMC based on the new tracking differentiator is high, the jitter is effectively reduced, and the noise-suppression ability is improved.

Establishing aqueous two-phase flotation coupled with preparative high performance liquid chromatography and its application for the purification of astragalin from Flaveria bidentis.

The strategy of aqueous two-phase flotation (ATPF) followed by preparative high performance liquid chromatography (prep-HPLC) was established and used for the separation of astragalin from Flaveria bidentis. In the ATPF, the effects of sublation solvent, solution pH, (NH4)2SO4 concentration in aqueous solution, cosolvent, N2 flow rate, flotation time and volumes of the PEG phase on the recovery of astragalin were investigated in detail, and the optimal conditions of ATPF were selected: 50 wt% PEG1000 ethanol solvent as the flotation solvent, pH 4, 350 g/L of (NH4)2SO4 concentration in 5 % ethanol aqueous phase, 40 mL/min of N2 flow rate, 30 min of flotation time, 10.0 mL of flotation solvent volume and twice. After ATPF enrichment, the flotation product was further purified by prep-HPLC. As determined by HPLC, the purity of astragalin was 98.8 %.

Dose Evaluation in 2-Phase Method for Advanced Esophageal Cancer by Hybrid Irradiation Techniques.

Purpose: In concurrent chemoradiotherapy for advanced esophageal cancer, a 2-phase method consisting of initial irradiation of a wide elective nodal region and boost irradiation of the primary lesion is commonly employed. Although dose escalation to the primary lesion may be required to achieve higher local control rates, the radiation dose to critical organs must not exceed dose constraints. To achieve an optimum balance of dose prescription and dose reduction to surrounding organs, such as the lungs and heart, we compared hybrid dose distributions and investigated the best combination of the following recent irradiation techniques: volumetric modulation arc therapy (VMAT), proton broad-beam irradiation, and intensity-modulated proton beam therapy (IMPT). Materials and Methods: Forty-five patients with advanced esophageal cancer whose primary lesions were located in the middle- or lower-thoracic region were studied. Radiotherapy plans for the initial and boost irradiation in the 2-phase method were calculated using VMAT, proton broad-beam irradiation, and IMPT calculation codes, and the dose-volume histogram indices of the lungs and heart for the accumulated plans were compared. Results: In plans using boost proton irradiation with a prescribed dose of 60 Gy(RBE), all dose-volume histogram indices were significantly below the tolerance limits. Initial and boost irradiation with VMAT resulted in the median dose of V30 Gy(RBE)(heart) of 27.4% and an achievement rate below the tolerance limit of 57.8% (26 cases). In simulations of dose escalation up to 70 Gy(RBE), initial and boost IMPT resulted in the highest achievement rate, satisfying all dose constraints in 95.6% (43 cases). Conclusion: Applying VMAT to both initial and boost irradiation is not recommended because of the increased risk of the cardiac dose exceeding the tolerance limit. IMPT may allow dose escalation of up to 70 Gy(RBE) without radiation risks to the lungs and heart in the treatment of advanced esophageal cancer.

Ultrasonication followed by aqueous two-phase system for extraction, on-site modification and isolation of microalgal starch with reduced digestibility.

Microalgae are new and sustainable sources of starch with higher productivity and flexible production modes than conventional terrestrial crops, but the downstream processes need further development. Here, ultrasonication (with power of 200 W or 300 W and duration of 10, 15, 20, or 25 min) was applied to simultaneously extract and modify starch from a marine microalga Tetraselmis subcordiformis for reducing the digestibility, and an aqueous two-phase system (ATPS) of ethanol/NaH2PO4 was then used to isolate the starches with varied properties. Increasing ultrasonic duration facilitated the partition of starch into the bottom pellet, while enhancing the ultrasonic power was conducive to the allocation in the interphase of the ATPS. The overall starch recovery yield reached 73 âˆ¼ 87 % and showed no significant difference among the ultrasonic conditions tested. The sequential ultrasonication-ATPS process successfully enriched the starch with purities up to 65 % âˆ¼ 88 %, which was among the top levels reported in microalgal starch isolated. Ultrasonication produced more amylose which was mainly fractionated into the interface of the ATPS. The digestibility of the starch was altered under different ultrasonic conditions and varied from different ATPS phases as well, with the one under the ultrasonic power of 200 W for 15 min at the bottom pellet having the highest resistant starch content (RS, 39.7 %). The structural and compositional analysis evidenced that the ultrasonication-ATPS process could exert impacts on the digestibility through altering the surface roughness and fissures of the starch granules, modulating the impurity compositions (protein and lipid) that could interact with starch, and modifying the long- and short-range ordered structures. The developed ultrasonication-ATPS process provided novel insights into the mechanism and strategy for efficient production of functional starch from microalgae with a potential in industrial application.

One-step high efficiency separation of prolyl endopeptidase from Aspergillus niger and its application.

Prolyl endopeptidase from Aspergillus niger (An-PEP) is an enzyme that recognizes C-terminal peptide bonds of amino acid chains and cleaves them by hydrolysis. An aqueous two-phase system (ATPS) was used to separate An-PEP from fermentation broth. Through single factor experiments, the ATPS containing 16 % (w/w) PEG2000 and 15 % (w/w) (NH4)2SO4 at pH 6.0 obtained the recovery of 79.74 ± 0.16 % and the purification coefficient of 7.64 ± 0.08. It was then used to produce soy protein isolate peptide (SPIP) by hydrolysis of soy protein isolate (SPI), and SPIP-Ferrous chelate (SPIP-Fe) was prepared with SPIP and Fe2+. The chelation conditions were optimized by RSM, as the chelation time was 30 min, chelation temperature was 25 °C, SPIP mass to VC mass was two to one and pH was 6.0. The obtained chelation rate was 82.56 ± 2.30 %. The change in the structures and functional features of SPIP before and after chelation were investigated. The FTIR and UV-Vis results indicated that the chelation of Fe2+ and SPIP depended mainly on the formation of amide bonds. The fluorescence, SEM and amino acid composition analysis results indicated that Fe2+ could induce and stabilize the surface conformation and change the amino acid distribution on the surfaces of SPIP. The chelation of SPIP and Fe2+ resulted in the enhancement of radical scavenging activities and ACE inhibitory activities. This work provided a new perspective for the further development of peptide-Fe chelates for iron supplement.

Morphological Integrated Preparation Method and Implementation of Inorganic/Organic Dual-Phase Composite Gradient Bionic Bone Scaffold.

Large bone defects caused by congenital deformities and acquired accidents are increasing day by day. A large number of patients mainly rely on artificial bone for repair. However, artificial bone cannot fully imitate the structure and composition of human bone, resulting in a large gap with autologous bone function. Therefore, this article proposes a continuous preparation method for inorganic/organic biphasic composite gradient biomimetic bulk bone scaffolds. First, a controllable gradient hybrid forming platform for inorganic/organic dual-phase biomaterials was constructed, and the feeding control strategy was studied to achieve precise control of the feeding of sodium alginate/gelatin composite organic materials and hydroxyapatite inorganic materials. The speed is, respectively, sent from the corresponding feeding nozzle to the mixing chamber to realize the uniform mixing of the biphasic material and the extrusion of the composite material, and the inorganic/organic biphasic composite gradient biomimetic bone scaffold with gradual structure and composition is prepared. Second, to prove the superiority of the preparation method, the physicochemical and biological properties of the prepared scaffolds were evaluated. The test results showed that the morphological characteristics of the biphasic composite gradient bone scaffold showed good microscopic porosity and the structure and composition showed gradients. The mechanical properties are close to that of human bone tissue and in vitro cell experiments show that the scaffold has good biocompatibility and bioactivity. In conclusion, this article provides a new type of bone scaffold preparation technology and equipment for the field of tissue engineering, which has research value and application prospects.

Two-Phase Electrosynthesis of Dihydroxycoumestans: Discovery of a New Scaffold for Topoisomerase I Poison.

Coumestan represents a biologically relevant structural motif distributed in a number of natural products, and the rapid construction of related derivatives as well as the characterization of targets would accelerate lead compound discovery in medicinal chemistry. In this work, a general and scalable approach to 8,9-dihydroxycoumestans via two-electrode constant current electrolysis was developed. The application of a two-phase (aqueous/organic) system plays a crucial role for success, protecting the sensitive o-benzoquinone intermediates from over-oxidation. Based on the structurally diverse products, a primary SAR study on coumestan scaffold was completed, and compound 3 r exhibited potent antiproliferative activities and a robust topoisomerase I (Top1) inhibitory activity. Further mechanism studies demonstrates that compound 3 r was a novel Top1 poison, which might open an avenue for the development of Top1-targeted antitumor agent.