A series of CuO/CeO2 and inverse CeO2/CuO catalysts are prepared by the surfactant-templated method and characterized via XRD, HRTEM, H2-TPR, SEM, XPS, in situ XRD, in situ UV–Vis and N2 ...adsorption–desorption techniques. It is found that there are two kinds of surface sites in the CuO–CeO2 system, including CuO surface sites for CO chemisorption and CeO2 surface sites with oxygen vacancies for oxygen sorption. The active sites for CO oxidation are located on the contact interface of two-kind surface sites and the lattice oxygen can make a significant contribution to the CO-PROX reaction. The resistance to H2O and CO2 is related to BET surface area, the crystallite sizes of CuO and the reduction behavior of catalysts. The Ce4Cu4 and Ce4Cu1 catalysts exhibit the best resistance against H2O and CO2.
The Ce4Cu4 and Ce4Cu1 catalysts possess high BET surface area, suggesting that the resistance ability to H2O and CO2 may be closely related the BET surface area. In addition, it is found that the resistance to H2O and CO2 is also associated with the crystallite sizes of CuO and the reduction behavior of catalysts. Display omitted
•CuO/CeO2 and inverse CeO2/CuO were prepared by surfactant-templated method.•CuO/CeO2 is ink-bottle-like pores and CeO2/CuO has narrow slit-like pores.•Lattice oxygen can make a significant contribution to the CO-PROX reaction.•Ce4Cu4 and Ce4Cu1 catalysts exhibit best resistance against H2O and CO2.•Resistance is related to BET surface area, crystallite sizes and reduction behavior.
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The precise control of active pharmaceutical ingredient (API) crystal nucleation and polymorphism is a key consideration in pharmaceutical manufacturing. In this study, tunable ...nanoparticles were developed to regulate the nucleation process of coumarin. Magnetic silica nanoparticles with four different functional groups (NH2, COOH, SH, NCO) were prepared and coated on the substrate for inducing the crystallization of coumarin. Confined melt crystallization and microspacing sublimation crystallization methods were used to investigate the regulation mechanism. The results indicated that three metastable forms of coumarin can be obtained as pure components based on the combined influence of crystallization methods and functionalized nanoparticles. Form II could be selectively obtained by microspacing sublimation crystallization on Fe3O4@SiO2SH substrates, and Form IV could be obtained by confined melt crystallization on Fe3O4@SiO2NCO substrates. Form III could be obtained by further heating Form IV crystals to 52 °C on Fe3O4@SiO2NCO substrates. Moreover, the polarized light microscopy results also indicated that the introduction of nanoparticles could also increase the stability of the metastable crystalline forms of coumarin. Finally, the diffusion and surface dynamics during nanoparticle induced crystallization were comparatively investigated and the corresponding polymorphic selectivity mechanism was proposed.
Current technologies that are used for genome-wide microRNA (miRNA) prediction are mainly based on BLAST tool. They often produce a large number of false positives. Here, we describe an effective ...approach for identifying orthologous pre-miRNAs in several primates based on syntenic information. Some of them have been validated by small RNA high throughput sequencing data. This approach uses the synteny information and experimentally validated miRNAs of human, and incorporates currently available algorithms and tools to identify the pre-miRNAs in five other primates. First, we identified 929 potential pre-miRNAs in the marmoset in which miRNAs have not yet been reported. Then, we predicted the miRNAs in other primates, and we successfully re-identified most of the published miRNAs and found 721, 979, 650 and 639 new potential pre-miRNAs in chimpanzee, gorilla, orangutan and rhesus macaque, respectively. Furthermore, the miRNA transcriptome in the four primates have been re-analyzed and some novel predicted miRNAs have been supported by the small RNA sequencing data. Finally, we analyzed the potential functions of those validated miRNAs and explored the regulatory elements and transcription factors of some validated miRNA genes of interest. The results show that our approach can effectively identify novel miRNAs and some miRNAs that supported by small RNA sequencing data maybe play roles in the nervous system.
•Impurity concentration polarization occurred at solid–liquid interface.•Mass transfer coefficient of impurity in melt boundary layer was derived.•Growth rate model correlating growth rate with ...temperature gradient of crystal layer was proposed.•Latent heat of crystallization decreases during crystallization due to impurity concentration polarization.
In this work, the effects of impurities on the growth behaviors of crystal layer during static layer melt crystallization (LMC) was studied. The crystal layer structure, growth rates, melt temperature curves and separation efficiency were experimentally investigated at different impurity concentrations and temperatures. With the experimental results, the mass transfer at the solid–liquid interface was discussed through: a) calculating the supercooling of the melt over the crystallization and b) deducing the mass transfer coefficient of impurity in the melt boundary layer. It was verified that the melt kept supercooled during the crystallization and concentration polarization occurred at the solid–liquid interface. A power law model was proposed to correlate the growth rate with the temperature gradient of crystal layer, which indicates that the concentration polarization results in the decrease of the latent heat of crystallization, and the mixture with lower impurity concentration and crystallization temperature would exhibit more serious concentration polarization.
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•Heat transfer of static layer melt crystallization in tubular crystallizer.•Structure of crystal layer with large amounts of bubbles.•Model correlating growth rate with physical and ...experimental parameters.•Effective thermal conductivity of crystal layer.•Four distinct stages in the process of static layer melt crystallization.
The growth behaviors of crystal layers during static layer melt crystallization was studied from the perspectives of morphology structure, growth rates and temperature evolution. The temperature distributions of the melt and crystal layer were deduced. With these results, the heat transfer during crystallization was analyzed by considering the relative influences of natural convection, heat conduction in the melt and latent heat of crystallization. A model correlating growth rate with physical and experimental parameters was derived based on energy conservation. Effective thermal conductivity of crystal layers was evaluated. It was confirmed that the structure and density of the crystal layer can significantly affect the thermal conductivity. According to the temperature curves of melt, the static layer melt crystallization process in a tubular crystallizer can be divided into four stages as nucleation stage, fast growth stage, slow growth stage and steady state stage.
•The proportion of activated mast cells and follicular helper T (Tfh) cells were found both significantly higher in dPAT than ndPAT, OVT and SAF samples.•The infiltrating Tfh cells have not ...previously been reported in PAT surrounding AAAs.•AP-1 family members (FOS, FOSB, ATF3, JUN and JUNB) were found among the hub genes of purple module and FOS was found as a good marker to discriminate dPAT from ndPAT, OVT and SAF in AAA.•FOS, FOSB, ATF3, JUN and JUNB are all significantly positive correlation with activated mast cell, plasma cell and Tfh cell infiltration in dPAT of AAA.
Abdominal aortic aneurysms (AAA) are pathological dilations in local aortic wall. The inflammatory infiltrates of the perivascular adipose tissue (PAT) surrounding AAAs were associated with AAAs and have been shown to contribute vascular pathology. However, the mechanism by which PAT inflammation contributes to vascular pathology in AAA remains to be clarified. This study aimed to explore the association between immune cell infiltration and key gene expression profile in PAT of AAA. For that, a gene expression dataset of human dilated perivascular adipose tissue (dPAT), non-dilated perivascular adipose tissue (ndPAT), subcutaneous abdominal fat (SAF) and omental-visceral fat (OVF) samples, as well as another microarray dataset of the abdominal perivascular adipose tissue in peripheral artery disease patients were downloaded from GEO database for analysis in this study. The CIBERSORT algorithm, weighted gene co-expression network analysis (WGCNA) and LASSO algorithm were used for the identification of immune infiltration, immune-related genes and the development of diagnostic signature. Our data discovered a significant higher proportion of activated mast cells and follicular helper T (Tfh) cells in dPAT than ndPAT, OVT and SAF samples. Moreover, AP-1 family members (FOS, FOSB, ATF3, JUN and JUNB) were found to compose the hub genes of purple module in WGCNA. Among them, FOS gene acts as a higher efficient marker to discriminate dPAT from ndPAT, OVT and SAF in AAA. Meanwhile, the expression profiles of the AP-1 family members are all significantly positive correlated with activated mast cell, plasma cell and Tfh cell infiltration in dPAT of AAA. Therefore, in the PAT surrounding AAA, the signature of inflammatory infiltration might be represented by a FOS-dominated cell network consist of activated mast cell, plasma cell and Tfh cell. Given the complicated etiology of AAA, our results are likely to shed new light on the pathophysiologic mechanism of AAA influenced by the local dPAT.
In this study, ring-banded spherulite films of ceftezole sodium monohydrate were obtained by evaporating droplets on a glass sheet. The formation of ring bands was analyzed in detail by using a ...scanning electron microscope and atomic force microscope. The evolution process of spherulites was monitored by intermittent sampling, and the results showed that the formation of ring bands was controlled by material transport. Furthermore, the additive gelatin was selected to construct a diffusion-limited system, in which the spherulites can be changed from radial growth to concentric ring-banded growth by slowing down the evaporation rate. The intermittently changing lamellae stacking mode of ring bands indicates that the lamellae are twisted due to the influences of various types of stress. Finally, a reasonable growth mechanism of ring-banded spherulites was proposed to reveal the assembly process of the hierarchical structure.
Three intrinsic properties of solvent were used to evaluate the effects of solvent on polymorph formation of prasugrel hydrochloride. In situ Raman spectroscopy, FTIR, and powder X-ray diffraction ...were used to characterize two solvent-free polymorphs and five solvates of prasugrel hydrochloride, the two of which were reported for the first time. Reactive crystallization in 24 different pure solvents was studied at 313.15 K. It was found that polymorph formation of prasugrel hydrochloride directly depends on the solvents used in the experiments. Form I was obtained in solvents with low values of hydrogen bond donor ability (HBD), while form II was obtained in solvents with high values of HBD. The thermodynamic and kinetic reasons for the solvent effects were explained by using the solubility data and the nucleation experiments. The solubilities of forms I and II were experimentally determined by a gravimetric method, and an equation based on the linear free energy approach for predicting solubility was applied to correlate the solubility of form II. It was found that the values of HBD of the solvents also affect the solubility of prasugrel hydrochloride. From desolvation experiments of the five solvates in seven pure solvents at 293.15 and 313.15 K, it was found that the polymorphs of prasugrel hydrochloride obtained after desolvation are closely related to the solvents. The heterogeneous nucleation of form I during the solvent-mediated polymorphic transformation was also studied at 313.15 K, and it was found that the solute–solvent interactions will also affect the nucleation rate of form I. A hypothesis was then proposed that prasugrel hydrochloride form I is prone to crystallize when van der Waals force dominates the interaction between the solute and the solvent molecules, while prasugrel hydrochloride form II is prone to nucleate and grow when hydrogen bonding dominates the interaction between the solute and the solvent molecules.
Protein drugs have attracted extensive attention from the academic community. However, crystallization of proteins is difficult and the yield of current main technologies is too low, which limits ...their large-scale industrial production. In this work, enhancement of continuous crystallization of lysozyme under an ultrasonic field was explored. A plug-flow tubular crystallizer, which was separated into a nucleation zone and a growth zone, was applied. The effect of ultrasound on steady-state time, crystal habit, particle size, particle size distribution, and the process yield was evaluated based on univariate analysis experiments. It was found that ultrasound can shorten the time for continuous crystallization to reach a steady state, reduce the degree of aggregation, and promote nucleation. Furthermore, the separation of the growth zone from the nucleation zone in the ultrasonic-assisted continuous crystallization can further increase the size of the lysozyme crystals, which would help in increasing the yield.
•Only PHE-rich solid solution can be formed in PHE-CAR-solvent ternary phase diagram.•Pure CAR can be separated from PHE-CAR mixture through solvent crystallization.•The difference coefficient of ...solubility (Ds) was put forward to assist screening solvents for separating PHE-CAR mixture.•Among DMF, acetone, MeCN and toluene, toluene is the most suitable solvent for separating PHE-CAR mixture.
The separation of phenanthrene (PHE) and carbazole (CAR) has been a tough job since the formation of solid solutions. Development of new separation strategy for PHE-CAR mixture highly depends on their phase equilibrium behaviour. In this work, ternary phase diagrams of phenanthrene (PHE) and carbazole (CAR) in dimethylformamide (DMF), acetone, acetonitrile (MeCN) and toluene at T = 308.15 K under normal atmosphere were determined through wet residue method. It was found that PHE-rich solid solution α was formed in the particular composition range of PHE-end. On the contrary, no CAR-rich solid solution was formed in CAR-end. These results were further verified through powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC). Based on the ternary phase diagrams, a difference coefficient of solubility (Ds) was put forward to assist screening and evaluation of solvents for solution crystallization. Among the four tested solvents, toluene is the most suitable one for separating PHE-CAR mixture.
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