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Particle-fluid system is one of the most popular systems in chemical processes. Owing to complex interface structure and high-velocity turbulence, the momentum and mass transfer exhibit nonlinear characteristics, which pose a great challenge for further study and application. To solve this problem, computational mass transfer (CMT) emerged and has been proved to be effective in deeply exploring the mass transfer behavior of particle-fluid systems. First, this paper reviews recent gas-solid numerical studies of turbulence issues from empirical to theoretical, then discusses interphase mass transfer rate models and the interfacial interaction force. Second, the present study particularly reviews researches on mass transfer process of fixed and fluidized regime by CMT, providing reliable analysis of turbulent anisotropy diffusivity as well as multiscale structure and presenting theoretical instruction for the industrial optimization of mass transfer processes in chemical engineering.

Flue gas and coal bed methane are two important sources of greenhouse gases. Pressure swing adsorption process has a wide range of application in the field of gas separation, and the selection of adsorbent is crucial. In this regard, in order to assess the better adsorbent for separating CO2from flue gas and CH4from coal bed methane, adsorption isotherms of CO2, CH4and N2on activated carbon and carbon molecular sieve are measured at 303.15, 318.15 and 333.15 K, and up to 250 kPa. The experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir–Freundlich models, and Clausius–Clapeyron equation was used to calculate the isosteric heat. Both the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO2 > CH4 > N2. The adsorption kinetics are calculated by the pseudo-first kinetic model, and the order of adsorption rates on activated carbon is N2 ≥ CH4 > CO2, while on carbon molecular sieve, it is CO2 ≥ N2 > CH4. It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon, while kinetic diameter is the main resistance factor for carbon molecular sieve. Moreover, the adsorption selectivity of CH4/N2and CO2/N2were estimated with the ideal adsorption solution theory, and carbon molecular sieve performed best at 318.15 K for both CO2and CH4separation. The study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.

The lateral flow immunoassay (LFIA) is a sought-after point-of-care testing platform, yet the insufficient sensitivity of the LFIA limits its application in the detection of tumor biomarkers. Here, a colorimetric signal amplification method, bimetallic nanozyme-mediated in situ-catalyzed reporter deposition (BN-ISCRD), was designed for ultrasensitive cancer diagnosis. The bimetallic nanozyme used, palladium@iridium core–shell nanoparticles (Pd@Ir NPs), had ultrahigh enzyme-like activity, which was further explained by the electron transfer of Pd@Ir NPs and the change in the Gibbs free energy during catalysis through density functional theory calculations. With gastric cancer biomarkers pepsinogen I and pepsinogen II as model targets, this assay could achieve a cutoff value of 10 pg/mL, which was 200-fold lower than that without signal enhancement. The assay was applied to correctly identify 8 positive and 28 negative clinical samples. Overall, this BN-ISCRD-based LFIA showed great merits and potential in the application of ultrasensitive disease diagnosis.

Reading and perceiving complex SQL queries has been a time consuming task in traditional database applications for decades. When it comes to decision support systems with automatically generated and sometimes highly nested SQL queries, human understanding or tuning of these workloads becomes even more challenging. This demonstration explores visualization methods to represent queries as graphs. We developed the QueryScopetool to help visualize and understand critical elements of a query, thereby cutting down the learning curve. We show how the tool allows the user to drill down on particular queries or to find similarly structured queries that may exhibit similar tuning opportunities. The queries shown in the demonstration are taken from real tuning engagements.

Polypeptoids are widely used in biological applications owing to their diverse functions and proteolytic stability. One type of polypeptoids, poly-N-methoxyethylglycine (P-Nmeg), has been found to possess remarkable hydrophilicity and notable properties in terms of protein, cell, and bacterial antifouling. However, the currently known synthesis methods of P-Nmeg include solid-phase synthesis, which is time-consuming and difficult to scale up, and N-substituted N-carboxyanhydride (NNCA) ring-opening polymerization, whose monomers were difficult to store. In this study, we used the chemical stable Nmeg N-phenoxycarbonyl (NPC) as the monomer, which was obtained without the use of highly toxic reactants, such as phosgene or phosphorus halide, to synthesize P-Nmeg under open-vessel conditions. By adding BnNH2as an initiator at 80 °C, we can obtain controllable short chain length P-Nmeg with narrow dispersity.

Efferocytosis and metabolic reprogramming of macrophages play crucial roles in myocardial infarction (MI) repair. TREM2 has been proven to participate in phagocytosis and metabolism, but how it modulates myocardial infarction remains unclear. In this study, we showed that macrophage-specific TREM2 deficiency worsened cardiac function and impaired post-MI repair. Using RNA-seq, protein and molecular docking, and Targeted Metabolomics (LC–MS), our data demonstrated that macrophages expressing TREM2 exhibited decreased SLC25A53 transcription through the SYK-SMAD4 signaling pathway after efferocytosis, which impaired NAD+transport into mitochondria, downregulated SLC25A53 thereby causing the breakpoint in the TCA cycle and subsequently increased itaconate production. In vitro experiments confirmed that itaconate secreted by TREM2+macrophages inhibited cardiomyocyte apoptosis and promoted fibroblast proliferation. Conversely, overexpression of TREM2 in macrophages could improve cardiac function. In summary, our study reveals a novel role for macrophage-specific TREM2 in MI, connecting efferocytosis to immune metabolism during cardiac repair.

The ability of wide-area and fast-revisit observation with beam scanning in both azimuth and elevation dimensions has allowed the airborne real aperture radar to be a hotspot in applications of aircraft formation identification and airborne warning and control system. However, the azimuth-elevation 2-D angular resolution is limited by antenna aperture size. When dealing with azimuth-elevation 2-D angular super-resolution of airborne real aperture radar for aerial targets, the existing super-resolution methods suffer from three problems: model mismatch, range and azimuth-elevation coupling, and high computational complexity, which lead to poor resolution and efficiency for the aerial target resolving. To circumvent this problem, this article proposes an azimuth-elevation 2-D joint super-resolution strategy for airborne real aperture radar. First, we establish an airborne azimuth-elevation 2-D scanning signal model, which accurately represents the migration of velocity in different directions. Then, an azimuth-elevation 2-D range migration correction method is proposed, which eliminates the range and azimuth-elevation coupling. To improve the efficiency of target resolution, a fast conjugate gradient iterative adaptive method is finally derived to rapidly reconstruct the azimuth-elevation 2-D target scatterings. Simulated and real datasets demonstrate that the proposed method is not only suitable for airborne 2-D angular super-resolution, but also achieves a competitive resolution capability with quite lower computational complexity.

Chemical looping combustion (CLC) involving multicomponent particles is favorable for the purpose of capturing CO2with a low energy penalty. While the complex flowing behavior in terms of mixing and segregation of particles makes it a challenge to have a deep understanding of hydrodynamics as well as its application. In this paper, a multifluid model based on the Eulerian–Eulerian approach is introduced for a three-dimensional (3D) simulation of the fluidization process in a chemical looping combustion system with binary particles consisting of heavy glass beads (GBs) and light polyethylene (PE) as two model metal oxides (i.e., oxygen carriers). The multifluid model integrates the kg– εg– ks– εs– Θ formulations for the description of turbulence flow and the EMMS drag for the interaction between particles and gas. With this model, the distributions of pressure and phase velocity as well as the solid circulation rate can be obtained. Also, satisfactory agreements are found between the predictions and experimental data, which validates the proposed model. It is observed that a higher fluidizing velocity in the air reactor (AR) and fuel reactor (FR) results in a higher solid circulation rate with less significant segregation. Increasing the diameter of heavy GB from 98 to 138 μm with a fixed PE diameter of 231 μm leads to a continuous intensification of the segregation behavior in AR and riser as well as FR, while the difference in values of averaged binary-mixture compositions (i.e., averaged light PE weight fraction) between AR and FR shows an inflection point where a relatively equal composition within the two reactors is reached when the GB diameter is 116 μm. Higher fluidizing velocity in loop seals just leads to a higher solid circulation rate, and it almost has no influence on the composition of binary particles in AR and FR, indicating a valve-like function of the loop seals.

While solution micellization of ionic block copolymers (BCP) with randomly distributed ionization sites along the hydrophilic segments has been extensively studied, the roles of positionally controlled ionization sites along the BCP chains in their micellization and resulting micellar structure remain comparatively less understood. Herein, three amphoteric polypeptoid block copolymers carrying two oppositely charged ionizable sites, with one fixed at the hydrophobic terminus and the other varyingly positioned along the hydrophilic segment, have been synthesized by sequential ring-opening polymerization method. The presence of the ionizable site at the hydrophobic segment terminus is expected to promote polymer association toward equilibrium micellar structures in an aqueous solution. The concurrent presence of oppositely charged ionizable sites on the polymer chains allows the polymer association to be electrostatically modulated in a broad pH range (ca. 2–12). Micellization of the amphoteric polypeptoid BCP in dilute aqueous solution and the resulting micellar structure at different solution pHs was investigated by a combination of scattering and microscopic methods. Negative-stain transmission-electron microscopy (TEM), small-angle neutron scattering (SANS), and small-angle X-ray scattering (SAXS) analyses revealed the dominant presence of core–shell-type spherical micelles and occasional rod-like micelles with liquid crystalline (LC) domains in the micellar core. The micellar structures (e.g., aggregation number, radius of gyration, chain packing in the micelle) were found to be dependent on the solution pH and the position of the ionizable site along the chain. This study has highlighted the potential of controlling the position of ionizable sites along the BCP polymer to modulate the electrostatic and LC interactions, thus tailoring the micellar structure at different solution pH values in water.

L-valve is often used as a non-mechanical valve for the circulation of solids in gas–solids fluidized bed (GSFB) due to its advantages in simple construction and easy control. The information on solids circulation rate as well as the hydrodynamics performance of the CFB with L-valve is of great importance for its better control and design. This paper proposes a Eulerian-Eulerian approach based numerical model integrating the computational fluid dynamics (CFD) with turbulent model, the kinetic theory of granular flow (KTGF) and the drag model, thus the solids circulation rate and the local phase velocity as well as solids volume fraction can be predicted simultaneously. With this model, the hydrodynamics performance of the full loop GSCFB with a L-valve is analyzed in detail. It is found that the drag model affects the simulation significantly and the (energy minimization multiscale) EMMS method shows good performance in the full-loop simulation of GSCFB.

In this work, a non-ionic, water-soluble rigid rod polymer was investigated for viability in replacing organic-soluble rigid rod polymers as these legacy rigid polymers require difficult solvents. Producing a rigid, water-soluble polymer that does not suffer from aggregation or ionic effects is a difficult proposition. Herein, the synthesis of a poly(lysine) with a short ethylene glycol side chain, PEGL, was duplicated, based on previous work by Deming et al.and characterized by various techniques. It was discovered that PEGL suffers from aggregation, evidenced by dynamic and static light scattering experiments that showed non-ideal rigid rod behavior and multiple decay rates. PEGL also showed a changing lower critical solution temperature when varying salt concentration. Although PEGL can exhibit a double helix conformation and has non-ionic side chains, the propensity for aggregation precludes PEGL from being used for fundamental polymer investigation.

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The Paternò–Büchi (PB) reaction is a carbon–carbon double bond (C═C)-specific derivatization reaction that can be used to pinpoint the location(s) of C═C(s) in unsaturated lipids and quantitate the location of isomers when coupled with tandem mass spectrometry (MS/MS). As the data of PB-MS/MS are increasingly generated, the establishment of a corresponding data analysis tool is highly needed. Herein, LipidOA, a machine-learning and prior-knowledge-based data analysis tool, is developed to analyze PB-MS/MS data generated by liquid chromatography–mass spectrometry workflows. LipidOA consists of four key functional modules to realize an annotation of glycerophospholipid (GPL) structures at the fatty acyl-specific C═C location level. These include (1) data preprocessing, (2) picking C═C diagnostic ions, (3) de novoannotation, and (4) result ranking. Importantly, in the result-ranking module, the reliability of structural annotation is sorted via the use of a machine learning classifier and comparison to the total fatty acid database generated from the same sample. LipidOA is trained and validated by four PB-MS/MS data sets acquired using different PB reagents on mass spectrometers of different resolutions and of different biological samples. Overall, LipidOA provides high precision (higher than 0.9) and a wide coverage for structural annotations of GPLs. These results demonstrate that LipidOA can be used as a robust and flexible tool for annotating PB-MS/MS data collected under different experimental conditions using different lipidomic workflows.

Zwitterionic ring-opening polymerization (ZROP) of sarcosine-derived N-thiocarboxyanhydrides (Me-NNTAs) can be induced by using 1,1,3,3-tetramethylguanidine (TMG) initiators in CH2Cl2at 25 °C, rapidly producing well-defined polysarcosine polymers with controlled molecular weights (Mn= 1.9–37 kg/mol) and narrow molecular weight distributions (Đ= 1.01–1.12). The reaction exhibits characteristics of a living polymerization, evidenced by pseudo-first-order polymerization kinetics, the linear increase of polymer molecular weight (Mn) with conversion, and the successful chain extension experiments. The polymerization is proposed to proceed via propagating macro-zwitterions bearing a cationic 1,1,3,3-tetramethylguanidinium and an anionic thiocarbamate chain end. The TMG not only initiates the polymerization but also serves to stabilize the thiocarbamate chain end where the monomer addition occurs. Because of the enhanced hydrolytic stability of Me-NNTA, the polymerization can be conducted without the rigorous exclusion of moisture, further enhancing the appeal of the method to access well-defined polysarcosine.

Based on the lens of spatial filter parallel auxiliary assembly and collimation method, aiming at the unloading and locking problem of the filter lens after collimating, a lens parallel adjustable axial locking structure was proposed. A special elastic chuck structure was designed to realize clamping axial friction locking; each branch realized interference fit, and the adjustable structure of “line-line-line” contact realized equivalent fixation through spring pre-tightening. Compared with radial locking, the abrupt error of the axial locking lens in the unloading process of a collimating auxiliary machine was small, and the posture state maintenance and structural response stability were strong. The established homogeneous transformation matrix (HTM) and lens global error showed that the pose torsion roll error of the radial locking structure was significantly suppressed. The relative stability experiment showed that the angular drift error of the lens axial locking structure was ± 0.2 µrad. The design effectively improved the unloading anti-mutation characteristics and stability of the filter lens, which provided an experimental basis for the application of intelligent collimation assisted assembly and adjustment scheme in the upgrading of a high-power laser device.

Interleukin‐37 (IL‐37) is a potent anti‐inflammatory cytokine belonging to the IL‐1 family. This study investigates the regulatory mechanism and reparative effects of IL‐37 on HF‐related human induced pluripotent stem cells derived cardiomyocytes (hiPSC‐CMs) and engineered human heart tissue subjected to hypoxia and H2O2treatment. The contractile force and Ca2+conduction capacity of the tissue are assessed using a stretching platform and high‐resolution fluorescence imaging system. This investigation reveals that IL‐37 treatment significantly enhances cell viability, calcium transient levels, contractile force, and Ca2+conduction capacity in HF‐related hiPSC‐CMs and engineered human heart tissue. Notably, IL‐37 facilitates the upregulation of sarcoplasmic reticulum calcium ATPase 2a (SERCA2a) through enhancing nuclear p‐STAT3 levels. This effect is mediated by the binding of p‐STAT3 to the SERCA2a promoter, providing a novel insight on the reparative potential of IL‐37 in HF. IL‐37 demonstrates its ability to enhance systolic function by modulating myocardial calcium handling via the p‐STAT3/SERCA2a axis in HF‐related engineered human heart tissue (as shown in schematic diagram). The specific regulatory mechanism and repair effect of IL‐37 on HF‐related hiPSC‐CM and human heart tissue are revealed. IL‐37 enhances systolic function by modulating myocardial calcium handling via the p‐STAT3/SERCA2a axis in HF‐related engineered human heart tissue. It will explore more effective solution for the treatment of HF, which has strong clinical significance.

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Phosphatidylethanolamines (PEs), ether-PEs, and phosphatidylserines (PSs) are glycerophospholipids harboring a primary amino group in their headgroups. They are key components of mammalian cell membranes and play pivotal roles in cell signaling and apoptosis. In this study, a liquid chromatography–mass spectrometry (LC–MS) workflow for deep profiling of PEs, ether-PEs, and PSs has been developed by integrating two orthogonal derivatizations: (1) derivatization of the primary amino group by 4-trimethylammoniumbutyryl-N-hydroxysuccinimide (TMAB-NHS) for enhanced LC separation and MS detection and (2) the Paternò–Büchi (PB) reaction for carbon–carbon double bond (C═C) derivatization and localization. Significant improvement of the limit of identification down to the C═C location has been achieved for the standards of PSs (3 nM) and ether-PEs (20 nM). This workflow facilitates an identification of more than 200 molecular species of aminophospholipids in the porcine brain, two times more than those identified without TMAB-NHS derivatization. Importantly, we discovered that the n-10 isomers in C16:1 and C18:1 of aminophospholipids showed elevated contribution among other isomers, which correlated well with an increased transcription of the corresponding desaturase (FADS2) in the human breast cancer cell line (MDA-MB-231) relative to that in the normal cell line (HMEC). The abovementioned data suggest that lipid reprograming via forming different C═C location isomers might be an alternative mechanism in cancer cells.

Delay generated by digital control will inevitably lead to negative damping of Modular Multilevel Converter (MMC), which also has significant impacts on the high-frequency stability of the integrated system. Controller parameter optimization is an effectively method for MMC impedance optimization and high-frequency resonance suppression. This paper firstly extends the sequence impedance model of MMC by considering delay effects, and analyzes the high-frequency impedance characteristics as well as the stability of the MMC integrated system. Then, the effect of delay on the frequency range of MMC shows negative damping can be analyzed quantitatively by a vector diagram. Based on the quantified frequency range, the boundary of controller parameters can be derived. Finally, an MMC impedance optimization method that traversal all the values within the derived parameter boundaries to obtain the optimal controller parameters that maximize the phase margin of the system.

To reduce the frequency deviation and the rate of change of frequency (RoCoF) in a low-inertia power system, some converters are required to provide the frequency response (FR) power normally associated with the frequency deviation and/or the RoCoF, by droop/inertia/PD control. In this article, a rapid power compensation (RPC)-based FR strategy is developed to optimize the ability to compensate grid imbalance power, by fully exploiting the converter idle capacity. To this end, first, mathematical proof demonstrated the improved performance of the RPC strategy in terms of frequency deviation suppression versus droop control, and in terms of RoCoF suppression versus inertia control, with identical converter capacity limit. Moreover, it is proven that the RPC strategy can achieve consistent FR performance with respect to the optimal PD control, i.e., it can maximize the suppression of frequency deviation and RoCoF simultaneously, yet avoiding the limitations due to unknown grid parameters. Finally, by analyzing the operation modes and identifying the pertinent switching logic, the detailed implementation of the proposed RPC strategy is developed. Its superb FR performance is verified by the experiment results in a two-converter low-inertia system, and simulation results in an IEEE four-machine two-area system.

Large number of energy points add great difficulty to construct reactive potential energy surfaces (PES). To alleviate this, exemplar-based clustering is applied to partition the configuration space into several smaller parts. The PES of each part can be constructed easily and the global PES is obtained by connecting all the PESs of small parts. This Divide and Conquer strategy is first demonstrated in the fitting of PES for OH3 with gaussian process regression (GPR) and further applied to construct PESs for CH5 and O+\CH4 with artificial neural networks (NN). The accuracy of PESs is tested by fitting errors and direct comparisons with previous PESs in dynamically important regions. As for OH3 and CH5, quantum scattering calculations further validate the global accuracy of newly fitted PESs. The results suggest that partitioning the configuration space by clustering provides a simple and useful method for the construction of PESs for systems that requires large number of energy points.

High-voltage resistant quasi-solid-state polymer electrolytes (QSPEs) are promising for enhancing the energy density of lithium–metal batteries in practice. However, side reactions occurring at the interfaces between the anodes or cathodes and QSPEs considerably reduce the lifespan of high-voltage LMBs. In this study, a copolymer of vinyl ethylene carbonate (VEC) and poly(ethylene glycol) diacrylate (PEGDA) was used as the framework, with a cellulose membrane (CE) as the supporting layer. Based on density functional theory calculations, 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI), an ionic liquid, was screened because of its lowest unoccupied molecular orbital energy level as a modifying agent for the in situ P(VECx-EGy)/Pyrz/LiTFSI@CE QSPEs synthesis. Pyr14+, with a lithiophobic alkyl chain, forms a dense positive ion shielding layer on the protruding tips of deposited lithium, facilitating uniform and smooth lithium deposition. Pyr14TFSI assists in constructing a stable solid electrolyte interphase (SEI) layer on the Li surface enriched with LiF, Li3N, and RCOOLi. The modulation of lithium deposition behavior on the anode by Pyr14TFSI ensures stable Li plating/stripping for >1500 h. A Li–Cu cell exhibits stable cycling for >200 cycles at a current density of 0.05 mA cm–2, with an average Coulombic efficiency of 92.7%. In situ polymerization ensures that P(VECx-EGy)/Pyrz/LiTFSI@CE QSPEs exhibit excellent interface compatibility with the anode and the cathode. The CR2032 button cell Li|P(VEC1-EG0.06)/Pyr0.4/LiTFSI@CE|LiCoO2demonstrates stable cycling with a negligible capacity decay of 0.083% per cycle for >390 cycles at 25 °C and 0.2 C when using a high-voltage LiCoO2(4.45 V) cathode. Furthermore, a 7.1 mAh pouch cell achieves stable charge–discharge cycles, confirming the pronounced stability of the as-fabricated QSPE at the interfaces of the high-voltage LiCoO2cathode and Li anode.

We investigated the temperature-dependent structural evolution of thermoreversible triblock terpolypeptoid hydrogels, namely poly(N-allyl glycine)-b-poly(N-methyl glycine)-b-poly(N-decyl glycine) (AMD), using small-angle neutron scattering (SANS) with contrast matching in conjunction with X-ray scattering and cryogenic transmission electron microscopy (cryo-TEM) techniques. At room temperature, A100M101D10triblock terpolypeptoids self-assemble into core–corona-type spherical micelles in aqueous solution. Upon heating above the critical gelation temperature (Tgel), SANS analysis revealed the formation of a two-compartment hydrogel network comprising distinct micellar cores composed of dehydrated A blocks and hydrophobic D blocks. At T≳ Tgel, the temperature-dependent dehydration of A block further leads to the gradual rearrangement of both A and D domains, forming well-ordered micellar network at higher temperatures. For AMD polymers with either longer D block or shorter A block, such as A101M111D21and A43M92D9, elongated nonspherical micelles with a crystalline D core were observed at T< Tgel. Although these enlarged crystalline micelles still undergo a sharp sol-to-gel transition upon heating, the higher aggregation number of chains results in the immediate association of the micelles into ordered aggregates at the initial stage, followed by a disruption of the spatial ordering as the temperature further increases. On the other hand, fiber-like structures were also observed for AMD with longer A block, such as A153M127D10, due to the crystallization of A domains. This also influences the assembly pathway of the two-compartment network. Our findings emphasize the critical impact of initial micellar morphology on the structural evolution of AMD hydrogels during the sol-to-gel transition, providing valuable insights for the rational design of thermoresponsive hydrogels with tunable network structures at the nanometer scale.

The design and operation of radial flow adsorber are crucial in large-scale industrial oxygen production, which necessitates accurate prediction of gas-solid transfer behavior. In this work, a developed Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) model combined with the adsorption model is proposed. The developed CFD-DEM model is validated by comparing simulated results with experimental data and empirical correlation. Subsequently, the effect of particle packing structure and particle shapes on the dynamic adsorption process are analyzed in detail. The results reveal the mechanism of particle packing structure affecting axial velocity distribution, showing that uneven distribution of resistance on the outer flow channel side leads to uneven axial velocity distribution in the bed. Compared to cylindrical adsorbents, the use of spherical adsorbents results in a more uniform axial velocity distribution, consequently reducing bed pressure drop. The study holds significant potential for optimizing gas distribution and improving separation efficiency in future industrial applications.

The P(VECx-CEAy)/LiTFSI@CE SPEs possess multi-capabilities, all in one, of dissociating LiTFSI, immobilizing TFSI−and thus setting free more Li+, and smoothly transferring Li+.

Trifluoromethane (CHF3) is a ubiquitous by-product of chlorodifluoromethane synthesis (CHClF2) and is regarded as one of the most potent greenhouse emissions. Despite the adverse effects on the environment, CHF3is the general method of exhaust gas incineration and is used for other purposes, for example, as a coolant and in plasma etching. This project establishes a flexible and efficient two-stage vacuum pressure swing adsorption (VPSA) process to generate pure CHF3and CHClF2simultaneously, improving the product’s recovery rate. The first-stage VPSA unit loading activated carbon is developed to obtain CHF3with the purity of 99%. CHClF2of 99.5% purity is obtained from the second-stage VPSA unit with NaX zeolite. The process simulation predicts that the two-stage coupled VPSA separation system can obtain CHF3and CHClF2simultaneously. Under the best process parameters, the purity of CHF3, the recovery rate of CHF3, the purity of CHClF2, and the recovery rate of CHClF2are 99, 77.71, 99.5, and 72.13%, respectively. In all, our research demonstrates that the two-stage VPSA system is a practicable and worthy prospect for research and development. In addition, it can recover and purify CHF3and CHClF2through an efficient and cost-effective method.

Abstract

We investigated the effect of cyclic chain topology on the molecular ordering and thermal stability of comb-shaped polypeptoid thin films on silicon (Si) substrates. Cyclic and linear poly(N-decylglycine) (PNDG) bearing long n-decyl side chains were synthesized by ring-opening polymerization of N-decylglycine-derived N-carboxyanhydrides. When the spin-coated thin films were subjected to thermal annealing at temperatures above the melting temperature (T> Tm), the cyclic PNDG films exhibited significantly enhanced stability against melt-induced dewetting than the linear counterparts (l-PNDG). When recrystallized at temperatures below the crystallization temperature (T< Tc), the homogeneous c-PNDG films exhibit enhanced crystalline ordering relative to the macroscopically dewetted l-PNDG films. Both cyclic and linear PNDG molecules adopt cis-amide conformations in the crystalline film, which transition into trans-amide conformations upon melting. A top-down solvent leaching treatment of both l/c-PNDG films revealed the formation of an irreversibly physisorbed monolayer with similar thickness (ca. 3 nm) on the Si substrate. The physisorbed monolayers are more disordered relative to the respective thicker crystalline films for both cyclic and linear PNDGs. Upon heating above Tm, the adsorbed c-PNDG chains adopt trans-amide backbone conformation identical with the free c-PNDG molecules in the molten film. By contrast, the backbone conformations of l-PNDG chains in the adsorbed layers are notably different from those of the free chains in the molten film. We postulate that the conformational disparity between the chains in the physically adsorbed layers versus the free chains in the molten film is an important factor to account for the difference in the thermal stability of PNDG thin films. These findings highlight the use of cyclic chain topology to suppress the melt-induced dewetting in polymer thin films.

The SF6adsorption isotherms on zeolite 13X, zeolite NaY, activated carbon, and silica gel were investigated over a temperature range of 298–358 K and at pressure from 0 to 1000 kPa. Experimental results demonstrated that the adsorption capacity of SF6was in the order AC > NaY > 13X > silica gel under the same adsorption pressure and temperature conditions. Moreover, the equilibrium isotherm data of SF6on different adsorbents were fitted with Langmuir, Langmuir–Freundlich, and Toth models. The agreement between the fitting isotherms and the experimental data increased with the increase of available fitting parameters in the equation of the isotherm model, and the Toth model was verified to be the best alternative for describing adsorption behaviors of SF6. Furthermore, the isosteric heats of adsorption of SF6on adsorbents were calculated by the Clausius–Clapeyron equation. Heats of adsorption of SF6on the four adsorbents first decreased and then increased with increasing SF6loading.

The use of chemical dispersants is a well-established approach to oil spill remediation where surfactants in an appropriate solvent are contacted with the oil to reduce the oil–water interfacial tension and create small oil droplets capable of being sustained in the water column. Dispersant formulations typically include organic solvents, and to minimize environmental impacts of dispersant use and avoid surfactant wastage it is beneficial to use water-based systems and target the oil–water interface. The approach here involves the tubular clay minerals known as halloysite nanotubes (HNTs) that serve as nanosized reservoir for surfactants. Such particles generate Pickering emulsions with oil, and the release of surfactant reduces the interfacial tension to extremely low values allowing small droplets to be formed that are colloidally stable in the water column. We report new findings on engineering the surfactant-loaded halloysite nanotubes to be stimuli responsive such that the release of surfactant is triggered by contact with oil. This is achieved by forming a thin coating of wax to stopper the nanotubes to prevent the premature release of surfactant. Surfactant release only occurs when the wax dissolves upon contact with oil. The system thus represents an environmentally benign approach where the wax coated HNTs are dispersed in an aqueous solvent and delivered to an oil spill whereupon they release surfactant to the oil–water interface upon contact with oil.

In this paper, a model of activated carbon was established by molecular simulation and the separation performance of N2and CH4on activated carbon was studied. In order to evaluate the adsorption selectivity and diffusion selectivity of N2and CH4, Grand Canonical Monte Carlo and molecular dynamic methods were used to obtain equilibrium adsorption isotherms and mean square displacements of N2and CH4on activated carbon with different pore sizes. Research results showed that the difference in adsorption isosteric heat of N2and CH4at the pore size of  0.46 nm is the largest, which is 5.759 and 7.03 kcal·mol−1(1 cal=4.184 J), respectively. Activated carbon with pore size of  0.46 nm has the best N2and CH4adsorption selectivity, while its diffusion selectivity is not obvious.

•A systematic evaluation and comparison of VPSA, TSVA, and TSA for CO2Capture was studied.•Effects of key operating parameters on process performances have been investigated.•VPSA process performed best in productivity and energy consumption.•TVSA Process would be an efficient CO2capture process if a suitable low-grade waste heat source was available.

Crystallization-driven self-assembly (CDSA) of amphiphilic polymers into well-defined nanoscopic structures with different morphologies and functionalities has attracted increasing attention. Here, we investigate the CDSA of coil–comb-shaped diblock copolypeptoids, namely, poly(N-methyl glycine)-b-poly(N-decyl glycine) (PNMG-b-PNDG), in dilute methanol solution using X-ray/neutron solution scattering in conjunction with cryogenic transmission electron microscopy techniques. A series of PNMG-b-PNDGs were synthesized by sequential benzyl amine-initiated ring-opening polymerizations of the corresponding N-substituted N-carboxyanhydrides, in which the degree of polymerization and the length of the blocks were varied. The PNMG-b-PNDG polymers with a lower volume fraction of the crystalline PNDG blocks (fPNDG= 0.44) were found to slowly self-assemble into one-dimensional long wormlike nanofibrils in methanol. The nanofibrils bear an anisotropic crystalline core where the comb-shaped PNDG blocks were stacked in a face-to-face fashion along the long axis of the nanofibrils. Upon increasing fPNDGto 0.61 and 0.68, the final morphology of PNMG-b-PNDG micelles changed from wormlike nanofibrils to rigid short nanorods and then two-dimensional nanosheets. The nanofibrils were formed by a self-seeding growth pathway that involves the initial formation of a few seeded crystals followed by the addition of soluble unimers to the preferred crystal facets resulting in the gradual elongation of the micelles. By contrast, the nanorods were formed by a two-stage process involving the formation of spherical micelles with an amorphous core in the first stage and rapid confined crystallization of the micellar core and their fusion into rodlike nanostructures at the second stage. Understanding the relationship between chemical composition, micellar morphology, and CDSA pathway of coil–comb-shaped diblock copolypeptoids is an important step toward the rational design of anisotropic polymeric nanostructures with tailorable morphology.

Peptoids are highly biocompatible pseudopeptidic polyglycines with designable substituents on the nitrogen atoms. The therapeutic and drug-carrying potential of these materials requires a fundamental understanding of their interactions with lipid bilayers. In this work, we use amphiphilic polypeptoids with up to 100 monomeric units where a significant fraction (26%) of the nitrogen atoms are functionalized with decyl groups (hydrophobes) that insert into the lipid bilayer through the hydrophobic effect. These hydrophobically modified polypeptoids (HMPs) insert their hydrophobes into lipid bilayers creating instabilities that lead to the rupture of vesicles. At low HMP concentrations, such rupture leads to the creation of large fragments which remarkably anchor to intact vesicles through the hydrophobic effect. At high HMP concentrations, all vesicles rupture to smaller HMP–lipid fragments of the order of 10 nm. We show that the technique for such nanoscale polymer–lipid fragments can be exploited to sustain highly hydrophobic drug species in solution. Using the kinase inhibitor, Sorafenib as a model drug, it is shown that HMP–lipid fragments containing the drug can efficiently enter a hepatocellular carcinoma cell line (Huh 7.5), indicating the use of such fragments as drug delivery nanocarriers.

The extraordinary progress of pluripotent stem cell research provides a revolutionary avenue to understand mammalian early embryonic development. Besides well‐established conventional mouse and human embryonic stem cells, the discoveries of naive state human stem cell, two‐cell‐like cell, and the newly defined “extended pluripotent” stem cell and “expanded potential” stem cell with bidirectional chimeric ability have greatly broadened the horizons of more pluripotent states recaptured and maintained in dish, infinitely approaching the totipotent blastomere state. Although all these pluripotent cell types can self‐renew and have the ability to differentiate into all the three germ layers, accumulating evidence suggests that these pluripotent states display distinct epigenetic characters. More strikingly, epigenetic reprogramming, including DNA methylation, histone modification, and chromatin remodeling, is required to reset the cell fate commitment, suggesting that epigenetic mechanisms may play an active and important role in the maintenance and transition among these pluripotent states. Here, we have reviewed studies on various pluripotent states, with a highlight on the epigenetic regulation during the interconversion. Stem Cells2019;37:1372–1380 Different pluripotent states exist and have been established in vitro, including two‐cell‐like cells, expanded potential stem cells and extended pluripotent stem cells, naive embryonic stem cells, and primed epiblast stem cells. Compared with postimplantation state, preimplantation state exhibits a more open chromatin structure, marked by DNA hypomethylation and enriched active histone modifications.

Cell adhesive and other functional peptides (such as RGD, KRSR, YIGSR, VAPG, and BMP-2 peptides) are extensively studied and utilized in tissue engineering scaffolds and biomedical devices to modulate cell functions. Though PEG is frequently used as the antifouling layer, it is unclear how it affects the performance of functional peptides. By analyzing the impact of PEG at short (OEG4), medium (OEG8), and long chain length (PEG2K), we reveal that PEG chain length is critical and a medium-length PEG enables functional peptides to display their optimal and genuine functions in cell adhesion, migration, and differentiation by providing excellent antifouling to minimize background noise of unwanted cell adhesion and high enough surface density of functional peptides. Our result provides new avenues for maximizing the genuine functions of peptides. This study also provides a solution to prevent the heterogeneous and even divergent results caused by inappropriate choice of antifouling PEG and provides a general guidance in identifying new functional peptides.

Ultrasonic testing (UT) is increasingly combined with machine learning (ML) techniques for intelligently identifying damage. Extracting significant features from UT data is essential for efficient defect characterization. Moreover, the hidden physics behind ML is unexplained, reducing the generalization capability and versatility of ML methods in UT. In this paper, a generally applicable ML framework based on the model interpretation strategy is proposed to improve the detection accuracy and computational efficiency of UT. Firstly, multi-domain features are extracted from the UT signals with signal processing techniques to construct an initial feature space. Subsequently, a feature selection method based on model interpretable strategy (FS-MIS) is innovatively developed by integrating Shapley additive explanation (SHAP), filter method, embedded method and wrapper method. The most effective ML model and the optimal feature subset with better correlation to the target defects are determined self-adaptively. The proposed framework is validated by identifying and locating side-drilled holes (SDHs) with 0.5λcentral distance and different depths. An ultrasonic array probe is adopted to acquire FMC datasets from several aluminum alloy specimens containing two SDHs by experiments. The optimal feature subset selected by FS-MIS is set as the input of the chosen ML model to train and predict the times of arrival (ToAs) of the scattered waves emitted by adjacent SDHs. The experimental results demonstrate that the relative errors of the predicted ToAs are all below 3.67% with an average error of 0.25%, significantly improving the time resolution of UT signals. On this basis, the predicted ToAs are assigned to the corresponding original signals for decoupling overlapped pulse-echoes and reconstructing high-resolution FMC datasets. The imaging resolution is enhanced to 0.5λby implementing the total focusing method (TFM). The relative errors of hole depths and central distance are no more than 0.51% and 3.57%, respectively. Finally, the superior performance of the proposed FS-MIS is validated by comparing it with initial feature space and conventional dimensionality reduction techniques.

Capture, utilization, and storage of CO2(CCUS) is an effective way to achieve a low carbon and sustainable future, and PSA is one of the CO2separation technologies that has been widely studied due to its advantages of simple equipment and low energy consumption. The uncertain flow state of the fluid can indeed have an impact on accurate modeling during the research process of capturing CO2with PSA. In this study, we compare the two-equation turbulent (TET) model based on the computational mass transfer method (Yu and Yuan, 2017 [1]) with the laminar model commonly assumed in previous studies, to investigate the dynamic PSA process involving multi-steps of carbon dioxide separation in a single-column, with the purpose of exploring the differences caused by selecting different flow state models during the modeling process. The study utilizes the two models to simulate a single column PSA process, which consists of adsorption, vacuuming, purging, and pressurization to capture CO2. The simulation results are compared with experimental data, and compared to the laminar model, the TET model is found to be more in line with the actual process. The effect of turbulent diffusion on the concentration and velocity distributions is also investigated by comparing the two models, and the radial distribution becomes more uniform as the turbulent diffusion is taken into account in the TET model. The intensity of turbulent diffusion is analyzed for each step, and the pressurization stage shows intense turbulent characteristics that will impact the whole process.

Halloysite nanotubes (HNTs), naturally occurring and environmental benign clay nanoparticles, have been successfully functionalized with amphiphilic polypeptoid polymers by surface-initiated polymerization methods and investigated as emulsion stabilizers toward oil spill remediation. The hydrophilicity and lipophilicity balance (HLB) of the grafted polypeptoids was shown to affect the wettability of functionalized HNTs and their performance as stabilizers for oil-in-water emulsions. The functionalized HNTs having relatively high hydrophobic content (HLB = 12.0–15.0) afforded the most stable oil-in-water emulsions containing the smallest oil droplet sizes. This has been attributed to the augmented interfacial activities of polypeptoid-functionalized HNTs, resulting in more effective reduction of interfacial tension, enhancement of thermodynamic propensity of the HNT particles to partition at the oil–water interface, and increased emulsion viscosity relative to the pristine HNTs. Cell culture studies have revealed that polypeptoid-functionalized HNTs are noncytotoxic toward Alcanivorax borkumensis, a dominant alkane degrading bacterium found in the ocean after oil spill. Notably, the functionalized HNTs with higher hydrophobic polypeptoid content (HLB = 12.0–14.3) were shown to induce more cell proliferation than either pristine HNTs or those functionalized with less hydrophobic polypeptoids. It was postulated that the functionalized HNTs with higher hydrophobic polypeptoid content may promote the bacterial proliferation by providing larger oil–water interfacial area and better anchoring of bacteria at the interface.

The adsorption isotherms of nitrous oxide (N2O) on zeolite 5A, 13X, activated carbon, ZSM-5, and silica gel were investigated by a static volumetric method. The pressure and temperature by measurement of adsorption isotherms ranged from 0 to 1 MPa and 298 to 358 K, respectively. In terms of the adsorption amount, zeolite 13X has the highest adsorption capacity at high pressure (>0.7 MPa), while activated carbon has the best performance at low pressure (<0.1 MPa). The Langmuir, Langmuir–Freundlich, and Toth models were employed to describe the isotherm data, and the Langmuir–Freundlich model showed the best correlation with experimental isotherm data on all adsorbents. In addition, the temperature-dependent Langmuir–Freundlich model was used to fit the N2O adsorption data on all adsorbents. The isosteric heats of N2O on all five adsorbents were calculated. The heat of N2O adsorption on 5A was up to 51.1 kJ/mol, which was the highest compared to 13X, activated carbon, ZSM-5, and silica gel.

Supplemental Digital Content is available in the text.

Supplemental Digital Content is available in the text.

Plasmacytoma variability translocation 1 (PVT1), an oncogene, has been reported to be highly expressed in many tumors, including human glioma, gastric cancer, and non-small cell lung cancer. Functionally, it could also regulate the development of tumor cells. However, its specific roles and pathogenesis in human gliomas are still not clear. This study investigated the function and mechanism of PVT1 knockdown in the proliferation and malignant transformation of human gliomas. We first examined the expression levels of PVT1 and miR-424 in human glioma tissues and cell lines. We also used gene manipulation techniques to explore the effects of PVT1 knockdown on cell viability, migration, invasion, and miR-424. We found that PVT1 knockdown effectively inhibited cell viability, migration, and invasion of human glioma cells and increased miR-424 expression. Based on the negative correlation between PVT1 and miR-424, we then confirmed the direct interaction between PVT1 and miR-424 using RNA immunoprecipitation (RIP) and luciferase reporter assays. Further, we established a xenograft nude mouse model to determine the role and mechanism of PVT1 on tumor growth in vivo. In addition, PVT1 knockdown was shown to promote miR-424 in vivo. In summary, the present study demonstrated that PVT1 knockdown could negatively regulate miR-424 to inhibit human glioma cell activity, migration, and invasiveness. PVT1 knockdown could negatively regulate miR-424 to inhibit cellular activity, migration, and invasiveness in human gliomas, which explained the oncogenic mechanism of PVT1 in human gliomas. It also suggested that PVT1 might be a novel therapeutic target for human gliomas.

The thermal rate coefficients of H + H2O2→ OH + H2O were obtained theoretically based on a recent fundamental invariant-neural network potential energy surface. The ring polymer molecular dynamics (RPMD) calculations were performed to get the rate coefficients with quantum effects, which are in good accord with some experimental values. The rate coefficients derived from extensive quasi-classical trajectory and canonical variational transition-state calculations also predict well the experimental results at high temperatures. The RPMD rate coefficients for H + H2O2→ OH + H2O are larger than H + H2O2→ H2+ HO2, but at very low temperatures below the room temperature, the H2+ HO2channel becomes dominant due to significant quantum tunneling effects in the H atom transfer process. Considering that the old experimental values vary widely from different groups, we expect that our theoretical investigations can motivate new experimental work, which facilitates a more reliable comparison between theory and experiment.

A six-step, two-bed dual-reflux pressure swing adsorption process for air separation using LiLSX zeolite was first developed and studied systematically. Then two original integrated vacuum pressure swing adsorption processes were well designed ground on the analysis of the mass transfer behavior in the adsorption column, in order to overcome some difficult obstacles that exists in a dual-reflux process, such as low processing capacity and high energy consumption. The performance comparison results show that the adsorbent productivity of dual-reflux process, integrated process I and process II were 17.436, 34.007, and 36.741 NLO2/(kg h) and the energy consumption of those were 1.897, 0.681, and 0.762 kW h/Nm3O2, respectively. Accordingly, for integrated process I and process II, performance parameters of processing capacity and adsorbent productivity are almost twice than that of a dual-reflux process, yet energy consumption is only one-third that of a dual-reflux process. Then in-depth discussions for these results were analyzed in detail and comparison between two integrated vacuum pressure swing adsorption processes and dual-reflux process and comparison of two different integrated vacuum pressure swing adsorption processes themselves were also investigated systematically.