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Subarachnoid hemorrhage (SAH), as one of the most severe hemorrhagic strokes, is closely related to neuronal damage. Neurogenesis is a promising therapy, however, reliable targets are currently lacking. Increasing evidence has indicated that CD24 is associated with the growth of hippocampal neurons and the regulation of neural stem/precursor cell proliferation. To investigate the potential effect of CD24 in astrocytes on neuron growth in the hippocampus, we used a Transwell co-culture system of hippocampal astrocytes and neurons, and oxyhemoglobin (OxyHb) was added to the culture medium to mimic SAH in vitro. A specific lentivirus was used to knock down CD24 expression in astrocytes, which was verified by western blot, quantitative real-time polymerase chain reaction, and immunofluorescent staining. Astrocyte activation, neurite elongation, neuronal apoptosis, and cell viability were also assessed. We first determined the augmented expression level of CD24 in hippocampal astrocytes after SAH. A similar result was observed in cultured astrocytes exposed to OxyHb, and a corresponding change in SHP2/ERK was also noticed. CD24 in astrocytes was then downregulated by the lentivirus, which led to the impairment of axons and dendrites on the co-cultured neurons. Aggravated neuronal apoptosis was induced by the CD24 downregulation in astrocytes, which might be a result of a lower level of brain derived neurotrophic factor (BDNF). In conclusion, the knock-down of CD24 in astrocytes suppressed hippocampal neuron growth, in which the SHP2-ERK signaling pathway and BNDF were possibly involved.

The Multidrug and Toxic Compound Extrusion (MATE) protein belongs to a secondary transporter gene family, which plays a primary role in transporting many kinds of substrates such as organic compounds, secondary metabolites, and phytohormones. MATE protein members exist in both prokaryotes and eukaryotes. However, evolution and comprehensive analysis of the MATE genes has not been performed in Rosaceae species. In the present study, a total of 404 MATEs genes were identified from six Rosaceae genomes (Prunus avium, Pyrus bretschneideri, Prunus persica, Fragaria vesca, Prunus mume, and Malus domestica) and classified into eight main subfamilies (I-VII) based on structural and phylogenetic analysis. Microcollinearity analysis showed that whole-genome duplication events might play a vital role in the expansion of the MATE genes family. The Ka/Ks analysis, chromosomal localization, subcellular localization, and molecular characteristics (length, weight, and pI) were performed using various bioinformatics tools. Furthermore, different subfamilies have different introns-exons structures, cis-acting elements, and conserved motifs analysis, indicating functional divergence in the MATE family. Subsequently, RNA-seq analysis and real-time qRT-PCR were conducted during Chinese pear fruit development. Moreover, PbMATE genes were significantly expressed under hormonal treatments of MeJA (methyl jasmonate), SA (salicylic acid), and ABA (abscisic acid). Overall, our results provide helpful insights into the functions, expansion complexity, and evolutions of the MATE genes in Chinese pear and five Rosaceae species.

Hydrothermal liquefaction of the third-generation biomass represented by microalgae can produce biocrude. However, the directly obtained biocrude has a high heteroatom content and a low higher heating value (HHV), which cannot meet the standards of biofuel. In this work, water-insoluble biocrude which was directly gained from microalgae hydrothermal liquefaction (HTL) was upgraded under four kinds of solvents (i.e., methanol, ethanol, acetone, and H₂O) and one type of catalyst (H₂O + Ru/C) at 240–400 °C for 1 h. The results show that the HHV and C and H contents of upgraded bio-oil increased and the O/C ratio decreased significantly after solvent upgrading. The highest upgraded bio-oil yield appeared in the case of ethanol upgrading and reached the maximum value of 82.8 wt % at 360 °C. The upgraded bio-oil yield of acetone upgrading increased from 45.8 to 68.2 wt % as the temperature increased within 240–400 °C. Also, esterification reactions between alcohol and acid in the supercritical system remarkably reduced the content of carboxyl-containing organic matter.

Extracellular polymeric substances (EPS) occur naturally and widely on the surface of microbial cells; their reducibility may play a crucial role in graphene oxide reduction. In this work, the conversion of graphene oxide (GO) into reduction graphene oxide (rGO) with EPS (extracted from Bacillus sp.NT 10) as green reductant had been conducted to explore their potential application for graphene preparation. The results showed the GO could be reduced by EPS, especially in the presence of NH4+, and a synergetic effect was found between EPS and NH4+. Further studies hinted the rGO could be also obtained from GO by EPS reduction even under a mild alkaline condition (pH = 8), lightly higher room temperature (40 °C) and a certain amount of time (24 h). The good reduction performance was found to be ascribed to the real deoxygenation of oxygenous functional groups and restoration of electronic conjugation within GO, according to the analysis of XRD, XPS and FT-IR as well as Raman spectra, while the electron-rich tryptophan-like protein and aromatic protein on the surface of EPS as well as the assistance of NH4+ should account for the deoxygenation and restoration in terms of the detection on Zeta potential, AFM and 3D-EEM. These findings revealed the reduction of GO with EPS would be a green, environment-friendly and promising path to obtain rGO, which may open a novel route for the preparing graphene alternatively.

In order to imitate wood truly in structure and content, a viscose solution was used to prepare a cellulose membrane with the hierarchically porous structure of wood by two-step process of ice-templating and low-temperature phase inversion for a solar steam device. The prepared cellulose membrane with microchannels observed by microscopy, which resembled those of wood, showed excellent wicking and water flux characteristics. The physical properties of cellulose membranes, including mechanical and thermal stability, allow their application in many fields. In evaluating of solar steam performance, the water evaporation rate of 1.56 kg m−2 h−1 from a graphene-coated cellulose membrane at the light density of 1 kW m−2 exceeded that of a cellulose membrane with pure water. The water evaporation rate of the cellulose membrane was higher than that of a wood-derived solar steam device. The conversion efficiency was increased from 40.72 to 95.57% with modification of the prepared cellulose membrane using graphene. The collected data showed that the cellulose membrane with a hierarchically porous structure was a promising alternative to wood-based solar steam devices, which have the limitations in the reproducibility of structure and composition.

In this study, a novel bisphenol-containing cyclohexane group [4,4′-(cyclohexane-1,1-diyl)bis(2-methoxyphenol) (CDBMP)] was synthesized. It was reacted with 4,4′-dichlorodiphenylsulfone to synthesi...

Functional membranes generally wear out when applying in harsh conditions such as a strong acidic environment. In this work, high acid‐resistance, long‐lasting, and low‐cost functional membranes are prepared from engineered hydrogen‐bonding and pH‐responsive supramolecular nanoparticle materials. As a proof of concept, the prepared membranes for dehydration of alcohols are utilized. The synthesized membranes have achieved a separation factor of 3000 when changing the feed solution pH from 7 to 1. No previous reports have demonstrated such unprecedentedly high‐record separation performance (pervaporation separation index is around 1.1 × 107 g m−2 h−1). More importantly, the engineered smart membrane possesses fast self‐repairing ability (48 h) that is inherited from the dynamic hydrogen bonds between the hydroxyl groups of polyacrylic acid and carbonyl groups of polyvinylpyrrolidone. To this end, the designed supramolecular materials offer the membrane community a new material type for preparing high acid resistance and long‐lasting membranes for harsh environmental cleaning applications., Size‐tunable hydrogen‐bond supramolecular nanoparticles are synthesized for separation membrane fabrication, which can work stably at pH = 1 condition and exhibit self‐repairing ability.

The application and functionalization of cellulose has been attracting increased attention in academic and industrial studies because of its wide range of sources, short renewable cycle, and low environmental impact. In order to enhance the application field of cellulose and decrease the environmental pollution for organic solvent associated with its preparation, cellulose foam with a vertically hierarchically porous structure similar to wood was designed and fabricated successfully from a cellulose aqueous solution using an ice templated in this study. The cellulose foam prepared using a 3 wt % concentration possessed a uniform vertical hierarchically porous structure, which could provide a pathway for the flow of water or air based on the capillary effect. The highest water wicking rate and flux were 7.8184 mm·s-1 and 29.49 mL·min-1·g-1, respectively, for the porous foam prepared using a 3 wt % concentration. The mechanical testing experiment showed that the porous structure did not reduce the amount of stress that the sample could endure before being damaged. The compression strength increased with increasing cellulose concentration in solution. Therefore, the hierarchical structure formed in the prepared cellulose foam effectively improved the water flux behavior and provided a structural basis for future applications of cellulose scaffolds.

Pure egg albumen fiber has potential applications in the food industry, biomedicine, drug-controlled release systems, and as a tissue engineering scaffold. However, this type of fiber has not been successfully prepared so far. In this study, pure egg albumen fiber was successfully prepared using the simple method of coaxial wet-spinning with a polysulfone (PSU) hollow fiber as a template. PSU solution and egg albumen solution were extruded into a coagulation bath of distilled water to fabricate egg albumen/PSU fiber, in which the egg albumen solution was wrapped up by the outside PSU layer. Continuous pure egg albumen fiber was obtained after heat treatment in hot water and removal of the PSU layer by dissolution in N, N -dimethylformamide. The prepared continuous egg albumen fiber with good gloss could be lifted along the axial direction. Scanning electron micrographs revealed a dense structure. This successful preparation of pure egg albumen fiber will enable the manufacture of egg albumen fiber composites with excellent application potential for tissue engineering scaffolds.

BackgroundWith a variety of physiological and pharmacological functions, menaquinone is an essential prenylated product that can be endogenously converted from phylloquinone (VK1) or menadione (VK3) via the expression ofHomo sapiensUBIAD1 (HsUBIAD1). The methylotrophic yeast,Pichia pastoris, is an attractive expression system that has been successfully applied to the efficient expression of heterologous proteins. However, the menaquinone biosynthetic pathway has not been discovered inP. pastoris.ResultsFirstly, we constructed a novel synthetic pathway inP. pastorisfor the production of menaquinone-4 (MK-4) via heterologous expression ofHsUBIAD1. Then, the glyceraldehyde-3-phosphate dehydrogenase constitutive promoter (PGAP) appeared to be mostsuitable for the expression ofHsUBIAD1 for various reasons. By optimizing the expression conditions ofHsUBIAD1, its yield increased by 4.37 times after incubation at pH 7.0 and 24 °C for 36 h, when compared with that under the initial conditions. We foundHsUBIAD1 expressed in recombinant GGU-23 has the ability to catalyze the biosynthesis of MK-4 when using VK1and VK3as the isopentenyl acceptor. In addition, we constructed a ribosomal DNA (rDNA)-mediated multi-copy expression vector for the fusion expression ofSaGGPPS andPpIDI, and the recombinant GGU-GrIG afforded higher MK-4 production, so that it was selected as the high-yield strain. Finally, the yield of MK-4 was maximized at 0.24 mg/g DCW by improving the GGPP supply when VK3was the isopentenyl acceptor.ConclusionsIn this study, we constructed a novel synthetic pathway inP. pastorisfor the biosynthesis of the high value-added prenylated product MK-4 through heterologous expression ofHsUBIAD1 and strengthened accumulation of GGPP. This approach could be further developed and accomplished for the biosynthesis of other prenylated products, which has great significance for theoretical research and industrial application.

Increasing evidence shows that static magnetic fields (SMFs) can affect microbial growth metabolism, but the specific mechanism is still unclear. In this study, we have investigated the effect of moderate-strength SMFs on growth and vitamin K2 biosynthesis of Flavobacterium sp. m1-14. First, we designed a series of different moderate-strength magnetic field intensities (0, 50, 100, 150, 190 mT) and exposure times (0, 24, 48, 72, 120 h). With the optimization of static magnetic field intensity and exposure time, biomass and vitamin K2 production significantly increased compared to control. The maximum vitamin K2 concentration and biomass were achieved when exposed to 100 mT SMF for 48 h; compared with the control group, they increased by 71.3% and 86.8%, respectively. Interestingly, it was found that both the cell viability and morphology changed significantly after SMF treatment. Second, the adenosine triphosphate (ATP) and glucose-6-phosphate dehydrogenase (G6PDH) metabolism is more vigorous after exposed to 100 mT SMF. This change affects the cell energy metabolism and fermentation behavior, and may partially explain the changes in bacterial biomass and vitamin K2 production. The results show that moderate-strength SMFs may be a promising method to promote bacterial growth and secondary metabolite synthesis.

This study investigates the effect of the constituents and temperature of a coagulation bath on the morphology and water absorption behavior of a skin–core filament, which has potential application in the field of controlled drug release, based on biomedical polyurethane (BPU) and native silk fibroin microparticles (NSFPs). BPU solution and BPU/NSFP blend solution were extruded from the cortex and core channel of a coaxial double injector into a coagulation bath with different constituents and at different temperatures to form filaments. Scanning electron microscopy analysis of the skin–core filament prepared by wet-spinning revealed that the addition of ethanol decreased the exchange speed between the solvent and non-solvent and led to the formation of micropores on the surface. Meanwhile, the interface between the cortex and core became pronounced and the water absorption capability of the filament decreased with increasing ethanol concentration in the coagulation bath. The high temperature of the coagulation bath also improved the exchange speed between the solvent and non-solvent; however, its effect on the morphology of the filament was weak. Thus, a skin–core filament with different morphologies and water absorption behaviors was fabricated by controlling the constituents and temperature of the coagulation bath during the wet-spinning process. This skin–core filament has potential applications in controlled drug release.

Meanquinone-7 (MK-7) can be produced by the fermentation of Bacillus subtilis (natto), which is known for its nutraceutical and pharmacological properties. This study focused on the separation and purification of meanquinone-7 from wet cells produced by Bacillus subtilis (natto) fermentation. Using ethanol to extract menaquinone-7 twice directly from the crude cells after fermentation produced a menaquinone-7 yield of 1.47mg/g. The crude extract was purified using macroporous resin and subsequent crystallization. After treatment with HPD722 resin, the purification of menaquinone-7 were 7.17-fold increased with recovery yields of 97.2%. Menaquinone-7 with purities of more than 96% were produced with recovery yield of 99.3% by recrystallized with 95% ethanol. The developed procedure can produce high-purity of menaquinone-7 as well as high recoveries. This is an economical, efficient and simple process to large-scale preparation of high-purity menaquinone-7.

High-field asymmetric waveform ion mobility spectrometry (FAIMS) is a powerful technique for the separation and characterization of gas-phase ions. However, the quantitative model for this technique is incomplete because previous studies on ion loss have mostly focused on ion neutralization and diffusion in the separation process and neglected ion annihilation owing to ion recombination in the transmission process. In this work, an ion recombination model of UV-FAIMS was described and validated using a broad range of experimental gas flow rates (0–800 L/h) and concentrations (10 ppb–100 ppm). The theoretical analysis provided a new solution method for important parameters and indicated the existence of a linear growth interval and a point of saturated signal intensity, both of which were explained by the introduced recombination loss factor and validated experimentally. In particular, the existence of saturation was verified for the first time. Based on this theory, ionization efficiencies of 4.56 × 10−5, 5.41 × 10−5, and 4.47 × 10−6 were calculated for 1,3-butadiene, acetone, and ammonia, respectively, at atmospheric pressure, with corresponding the recombination coefficients of 2.56 × 10−7, 3.74 × 10−7, and 1.89 × 10−8 cm3s−1. Further, an optimized quantitative model of UV-FAIMS was proposed by incorporating ion recombination theory, providing the optimum quantitative interval and a parameter optimization method for UV-FAIMS, which were also validated using a wide range of experimental conditions. This work provides a basis for parameter optimization for UV-FAIMS and a new method of determining the ionization efficiency and recombination coefficient of a gas-phase analyte. Furthermore, the incorporation of ion recombination theory is instructive for the construction of quantitative models of atmospheric-pressure photoionization mass spectrometry and UV-ion mobility spectrometry.

Background: In recent years, pyrazole carboxamide derivatives possessed excellent fungicidal activity. In the process of designing new fungicides, the carboxamide group was modified in order to find novel structure pyrazole carboxamide derivatives. Methods: Ten novel trifluoromethyl pyrazole acyl thiourea derivatives were designed and synthesized. In vivo fungicidal activities of these compounds were tested against Fusarium oxysporum, Corynespora mazei and Botrytis cinerea, respectively Results: Particularly compounds exhibited significant control effective at 100 mg/L. More importantly, some compounds showed the good control effective at 10 mg/L. Furthermore, docking was established to study the structure-activity relationship of the title compounds. Conclusion: It is possible that trifluoromethylpyrazole acyl thiurea derivatives, which possess good control effective against Botrytis cinerea, may become novel lead compounds for the development of fungicides with further structure modification.

In this study, we report the remarkable recognition and assembly characteristics of D3h symmetric basket 16– containing two adjoining and nonpolar cavities with six biocompatible GABA residues at their northern and southern termini., In this study, we report the remarkable recognition and assembly characteristics of D3h symmetric basket 16– containing two adjoining and nonpolar cavities with six biocompatible GABA residues at their northern and southern termini. From the results of experimental (1H NMR, fluorescence and UV-Vis spectroscopies) and computational (MM-MC/OPLS3e) investigations, we deduced that hexaanionic 16– captured two molecules of anticancer drug doxorubicin 2+ in water and accommodated them in its two deep cavities. The formation of stable 16–⊂222+ (Ka = 3 × 1012 M–2) was accompanied by the exceptional homotopic cooperativity (α = 4K2/K1 = 112) in which K1 = 3.2 ± 0.8 × 105 M–1 and K2 = 9 ± 1 × 106 M–1. Furthermore, bolaamphiphilic 16–⊂222+ assembled into spherical nanoparticles (DLS, cryo-TEM and TEM) possessing 41% drug loading. The preorganization of abiotic receptor 16– and its complementarity to 2+ have been proposed to play a part in the positive cooperativity in which ten favorable noncovalent contacts (i.e. hydrogen bonds, salt bridges, C–H···π and π–π contacts) are formed between doxorubicin and the dual-cavity host. In the case of topotecan 3+, however, the absence of multiple and favorable basket⊂drug interactions resulted in the predominant formation of a binary 16– ⊂ 3+ complex (K1 = 2.12 ± 0.01 × 104 M–1) and the negative homotopic allostery (α ≪ 1). To summarize, our study lays out a roadmap for creating a family of novel, accessible and multivalent hosts capable of complexing anticancer agents in a cooperative manner. As basket⊂drug complexes organize into highly loaded nanoparticles, the reported soft material is amenable to the bottom-up construction of stimuli-responsive nanomedicine capable of effective scavenging and/or delivery of drugs.

Salt accumulation on photothermal layers significantly complicates the operation of solar evaporation systems by decreasing evaporation efficiency and resulting in unstable desalination performance. Despite numerous efforts directed at the development of salt-resistant solar steam generation devices, the challenge of preventing salt accumulation on the photothermal layer while simultaneously maintaining durability, portability, and high photothermal performance isn't yet solved. Herein, we propose a new self-desalting solar evaporation system comprising reduced graphene oxide (RGO)/cotton fabric on a vertically oriented porous polyacrylonitrile foam (VOPPF), demonstrating that no accumulation of salt occurred on the surface of the RGO/cotton fabric in simulated seawater (3.5 wt% NaCl) during 12 h desalination. Moreover, under simulated solar illumination, an extreme amount of salt (2 g NaCl) placed on the RGO/cotton fabric was fully rejected in simulated seawater (after 90 min). The hydrophilicity of the cotton fabric, floatability of VOPPF in water, and continuous water pumping promoted the re-dissolution of salt hindering its accumulation on the photothermal layer during desalination. Simultaneously, the intrinsic features of the RGO/cotton fabric (high durability, portability, and high light absorption efficiency) and VOPPF (low thermal conductivity along the channel direction) allowed for a remarkably high photothermal performance (a clean water production rate of ∼4.0 L m−2 d−1) under one sun illumination. Therefore, the developed evaporation system was sufficiently efficient, stable, and portable for direct solar desalination.

Phase inversion induced by water droplets has garnered attention in the field of polymer science as a novel method for preparing porous membranes. This study investigates the effect of the porous structure of poly (lactic acid) (PLA) membranes prepared through phase inversion induced by water droplets at four different temperatures (25, 50, 75, and 100 °C) on the morphology and proliferation of 3T3 cells. The surface properties of the PLA porous membrane, including pore size, pore size distribution, surface roughness, surface hydrophilicity, and cytocompatibility with 3T3 cells, were evaluated. The results indicated that the synthesized PLA membrane had two surfaces with different structures. The upper surface in contact with the water droplets during preparation contained uniformly distributed micropores, whereas the bottom surface was smooth and composed of small particles in contacted with the mold. The upper surface showed high cytocompatibility with 3T3 cells, and the 3T3 cells migrated and grew within the pores at 25 °C. In contrast, the bottom surface exhibited low biocompatibility with the 3T3 cells. Our study has wide-ranging implications and will improve the fabrication and implementation of 3D cultured scaffolds with excellent cytocompatibility.

Fuel-rich combustion is a promising technique to produce hydrogen by reforming hydrocarbons. Predictive modeling of the fuel reforming process needs a reliable chemical mechanism which is usually validated using laminar flame speed (LFS) data. While LFSs have been extensively employed to optimize mechanisms under fuel-lean, stoichiometric, and slightly fuel-rich conditions, it remains a formidable challenge to measure the LFSs of very rich mixtures (e.g., equivalence ratio ϕ ≥ 2 ) due to significant soot formation in such conditions, which leads to the LFS data under fuel-rich conditions being rather scarce. To overcome the challenge, a clear understanding of soot formation and its impact on LFS measurements is required. In this work, a series of one-dimensional outwardly propagating spherical flames (OPFs) with and without considering soot formation are simulated for rich ethylene/air mixtures ( 2.0 ≤ ϕ ≤ 3.5 ), in order to understand soot dynamics and morphology in the OPFs and to quantify the effects of soot formation on the determination of LFS using the OPF method under fuel-rich conditions. To this end, a detailed chemistry accounting for major pathways of PAH formation up to A7 (coronene, C 24 H 12 ) is employed and coupled with a state-of-the-art soot model considering nucleation, condensation, coagulation, surface growth, oxidation, and fragmentation. It is found that soot dynamics and morphology are very sensitive to the change in equivalence ratio and flame radius. Specifically, surface growth and oxidation play a dominant role in soot formation/evolution and can balance each other at ϕ = 2.0 , resulting in limited soot formation. However, the PAH-based condensation can dominate over other processes at ϕ ≥ 2.5 and hence a large amount of soot is observed. Moreover, the maximum value of primary particle diameters would tend to a constant as the flame radius increases. The results also show that the ratio between total soot mass and the mass of burned gas, m soot / m burned , follows an exponential law given by m soot / m burned = 10 0.47 ϕ − 3.76 , implying that soot formation can be exponentially enhanced by increasing equivalence ratio. Furthermore, it is found that under very rich conditions, the presence of soot has a significant impact on the determination of LFS, which leads to the measured LFS at ϕ = 3.5 being 22% lower than 1D planar adiabatic flame speed. This is mainly attributed to the thermal and flow effects of soot radiation, i.e., the reduction of flame temperature and negative flow speed of the burned gas. The above findings suggest that the impact of soot radiation should be carefully treated when determining the LFSs of rich premixed mixtures at ϕ ≥ 2.0 .

The dynamic characteristics of N2O emissions and nitrogen transformation in a sequencing batch biofilm reactor (SBBR) using the completely autotrophic nitrogen removal over nitrite (CANON) process coupled with denitrification were investigated via 15N isotope tracing and thermodynamic analysis. The results indicate that the Gibbs free energy (ΔG) values of N2O production by the nitrifier denitrification and heterotrophic denitrification reactions were greater than that of NH2OH oxidation, indicating that N2O was easier to produce via either nitrifier and heterotrophic denitrification than via NH2OH oxidation. Ammonia-oxidizing bacteria (AOB) denitrification exhibited a higher fs0 (the fraction of electron-donor electrons utilized for cell synthesis) than NH2OH oxidation. Therefore, AOB preferred the denitrification pathway because of its growth advantage when N2O was produced by the AOB. The N2O emissions by hydroxylamine oxidation, AOB denitrification and heterotrophic denitrification in the SBBRs using different C/N ratios account for 5.4–7.6%, 45.2–60.8% and 33.8–47.2% of the N2O produced, respectively. The total N2O emission with C/N ratios of 0, 0.67 and 1 was 228.04, 205.57 and 190.4 μg N2O-N·g−1VSS, respectively. The certain carbon sources aid in the reduction of N2O emissions in the process.

Prenyltransferase NovQ is a vital class involved in the biosynthesis of secondary metabolites such as clorobiocin and novobiocin. To investigate the relationship between structure and catalytic properties of NovQ, here, we have analyzed the substrate-binding site, namely PT barrel, and revealed that menadione hydroquinol formed intermolecular interactions with the residue Glu281 near the center of the active pocket. In this study, Glu281 was substituted with 9 diverse amino acids and catalytic properties of mutants were observed in vitro. Among them, E281Q showed 2.05-fold activities towards the aromatic substrate and prenyl donor, while others obtained catalytic efficiency between 8.4 and 88.6% of that of wild-type NovQ. Furthermore, the effects of catalytic conditions and substrate status on the activity of NovQ and its mutants were considered to obtain the optimized prenylated reaction. When the evolutionary NovQ variant E281Q was overexpressed in the host constructed to synthesize dimethylallyl diphosphate through the engineered mevalonate (MVA) pathway, we harvested up to 4.7 mg/L prenylated menadione at C-3 position by exogenously supplying the aromatic substrate. The construction of the microbial platform based on NovQ opens a new orientation to further biosynthesize various vitamin K2 with other ABBA prenyltransferases in E. coli.

Thirteen novel trifluoromethylpyrazole acyl urea derivatives were designed and synthesized. In vivo fungicidal activities of these compounds were tested against Fusarium oxysporum, Corynespora mazei, Botrytis cinerea and Pseudomonas syringae respectively, particularly compounds exhibited significant control effective at 100 mg/L. More importantly, some compounds showed the good control effective at 10 mg/L. Furthermore, docking was established to study the structure-activity relationship of the title compounds. It is possible that trifluoromethylpyrazole acyl urea derivatives, which possess good control effective against Fusarium oxysporum, Corynespora mazei and Botrytis cinerea, may become novel lead compounds for the development of fungicides with further structure modification.

Numerous physiological functions of menaquinone-7 (MK-7) act to reduce vascular calcification, suggesting that MK-7 may be a potential therapy for Alzheimer’s and Parkinson’s disease, and in this study, we attempted to increase the concentration of MK-7 synthesized by Bacillus subtilis natto, a standard nattokinase (NK) producing strain. Different Bacillus subtilis isolates demonstrated positive correlations between MK-7 and NK concentrations. Response surface methodology (RSM) was employed to optimize a culture medium for the simultaneous production of these molecules; the optimized medium contained the following components (%, w/v): soybean curd residue, 12.2; soya peptone, 5.7; lactose, 2.6; and K2HPO4, 0.6. The fermentation process was subsequently optimized based on online feedback control of fermentation process parameters. The dissolved oxygen (DO) concentration played an important role in the production of MK-7 and NK. With increased DO concentrations, the cell growth rate and NK activity increased. In contrast, at low DO concentrations, the concentration of MK-7 rapidly increased during the late fermentation stage. Thus, in this study, the production of MK-7 and NK by Bacillus subtilis was accomplished using soybean curd residue through medium optimization and DO control. This novel coproduction strategy was developed by controlling the aeration rate during the fermentation process. The concentrations of MK-7 and NK achieved in this study reached 91.25 mg/L and 2675.73 U/mL, respectively.

Sn is a kind of low melting point metal and can be used as a liquid coolant due to its higher thermal conductivity. Compared with the currently used sodium liquid coolant, Sn is more chemically stable and unfeasible to fire or explore when contacting with air or water. The chemical reactions between Sn and 304 stainless steel that is widely used as primary circuit pipeline materials in fast reactor were researched, and the effect of temperature on the corrosion behavior between 304 stainless steel and liquid Sn was discussed. The results show that pitting happens when the temperature is lower than 823 K, and dissolution happens when the temperature is higher than 823 K.

Recent studies have shown that Soret diffusion has strong impact on the laminar flame speed of hydrogen/air mixture while it has little influence for hydrocarbon fuels at normal temperature and pressure. However, it is not clear whether the same conclusions hold under engine-relevant conditions. This is investigated in the present study. A series of premixed spherical flames propagating at high temperatures and pressures are simulated for different fuels, and the corresponding laminar flame speeds with and without considering Soret diffusion are obtained. It is found that for hydrogen/air mixture, Soret diffusion has much stronger influence on burning rate at engine-relevant conditions than at normal temperature and pressure. However, for hydrocarbon fuels like methane and iso-octane, Soret diffusion still has negligible effects on the burning rate even under engine-relevant conditions.

In this study, filaments comprising natural silk fibroin microparticles (NSFP) and biomedical polyurethane (BPU) were prepared via wet-spinning as a reusable-controlled drug-delivery system. The rheological properties of the spinning solution were studied to examine the effect of NSFP on the BPU/NSFP filament formation. The influences of NSFP content and spinning conditions on the morphology, molecular interactions, mechanical properties, and swelling performance of BPU/NSFP filaments were also investigated. The morphology and mechanical property studies showed that NSPF and BPU exhibit good compatibility. The capacity of the BPU/NSFP filaments as drug loading carriers and drug release behavior were studied by spectroscopy. The presence of NSFP in the drug controlled system increase the drug loading amount and enhance the drug release time. This paper presents a well-designed manufacturing method for preparing BPU/NSFP filaments with good controlled drug delivery.

In this study, water droplets generated using an ultrasonic atomizer at room temperature were replaced with water droplets heated to a high temperature (further denoted as hot water droplets) by an electrical heating steam generator during the preparation of porous membranes via phase inversion to reduce the amount of consumed water and fabrication time. As a result, porous polylactic acid (PLA) membranes were successfully prepared, and their microstructure and physical properties were studied by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Further, the effect of the PLA concentration on the morphology and thermal properties of the produced membranes was investigated. The application of hot water droplets significantly improved the exchange rate between the solvent and non-solvent phases, which increased the average pore diameter. Increasing the PLA concentration decreased the pore diameter, and the produced pores became irregular due to the decrease in the mobility of PLA molecules. At the same time, the higher PLA concentrations also increased the thermal stability and crystallinity of the porous membranes which were fabricated without using any toxic coagulants has and thus could be potentially used in tissue engineering and artificial organ development.

In this study, a bisphenol containing spiral ring (BP-310) was synthesized with a facile one-step reaction routine. It was copolymerized with terephthaloyl acid chloride (TPC)/isophthalic acid chloride (TPC) and bisphenol A (BPA) to yield intrinsic porous co-polyarylates. The resultant co-polyarylates were found to have good thermal properties with glass transition temperature of 199.6–223.3 °C and initial degradation temperature of 463–482 °C. They could be dissolved in dichloromethane, DMSO, NMP and supplied transparent films with transparency of 86.2–89.4% at 450 nm. Also they were found to have good melt-flowability with melt viscosity of 414–6756 Pas (282–310 °C) and can be injected into different samples with good tensile strength and modulus of 71–73.9 MPa and 1.8–2.4 GPa. With the introduction of intrinsic porous spiral ring, the dielectric constant of the co-polyarylates decreased gradually from 3.0 down to 2.16 (at 107 Hz), tan loss factor reduced from 4.3*10−2 to 2.3*10−2 (at 107 Hz), 9.7*10−3 to 8.3*10−3 (at 104 Hz) respectively. As we expected, with the introduction of spiral ring into the polyarylate molecular chain provides a facile and low cost routine to fabricate intrinsic porous high performance materials, it can be potentially applied in these fields such as high frequency communication system such as 5G/6G.

In this study, wood-based activated carbon fibers (WACF) were modified by Ag nanoparticles (AgNPs) and TiO2 films. The coating of TiO2 films decreased the AgNPs agglomeration and exfoliation on WACF. As the soaking concentration of AgNO3 solution (Sconc) increased, AgNPs size and content increased, while the pore volume (especially micropore volume) of fibers reduced. However, at higher Sconc in the range of 0.2 to0.4 mol/L, only slight variations in AgNPs content and pore structure were observable for WACF/TiO2/Ag (Ag-containing WACF coated by TiO2 film). WACF/TiO2/Ag-0.1 (0.1 was the soaking concentration of AgNO3 solution, mol/L) represented the best self-regeneration performance under the visible light irradiation. The self-regeneration performance of WACF/TiO2/Ag was determined by the synergistic effects of two factors: adsorption and photodegradation. The abundant pores of WACF/TiO2/Ag-0.1 increased the methylene blue (MB) concentration of TiO2 surrounding and facilitated the MB photodegradation. Meanwhile, their suitable Ag content enhanced MB photodegradation. Furthermore, the principal pathway of a chemical reaction between Ag+ and WACF was interpreted based on the data of surface elemental constituents and surface functional groups.

Bacillus subtilis natto is a GRAS bacterium. Nattokinase, with fibrinolytic and antithrombotic activities, is one of the major products of this organism. It is being gradually recognized that B. subtilis natto can also be used as a biosynthetic strain for vitamin K2, which has phenomenal benefits, such as effects in the prevention of cardiovascular diseases and osteoporosis along with antitumor effects. Knocking out of the aprN gene by homologous recombination could improve the redox potential and slightly increase the concentration of MK-7. By detecting the change in redox potential during the growth of B. subtilis natto, a good oxygen supply and state of the cell membrane were found to be beneficial to vitamin K2 synthesis. A two-step RSM was used to optimize the operation parameters and substrate concentration in the new residue-free fermentation culture. The optimal conditions for the residue-free medium and control were determined. The optimum concentrations of soybean flour, corn flour, and peptone were 78.9, 72.4, and 24.8 g/L, respectively. The optimum rotational speed and volume of the culture medium using a shaking flask were 117 rpm and 10%, respectively. The state and composition of the cell membranes were more stable when engineered bacteria were cultured in this residue-free fermentation medium. Finally, the concentration of MK-7 increased by 37% to 18.9 mg/L, and the fermentation time was shortened by 24 h.

Temperature is a critical parameter that can control the morphology of poly (lactic acid) (PLA) porous membranes prepared through phase inversion induced by water droplets. It determines the volatilization rate of the solvent and the exchange rate between the solvent and nonsolvent. In this work, in order to investigate the effect of temperature on the morphology, PLA porous membranes were prepared via phase inversion induced by water droplets at different temperatures. The morphologies of the prepared membranes were observed using scanning electron microscopy, and the volatilization rate of the solvent and the exchange rate between the solvent and nonsolvent were tested separately. The experimental data indicated that the volatilization rate of the solvent was faster than the exchange rate between the solvent and nonsolvent. A uniform porous structure was obtained for the PLA membrane, and the pore size decreased with the increase in temperature from 25 °C to 75 °C. This result indicated that a PLA porous membrane with desired pore size could be achieved by adjusting the ambient temperature.

Development of high temperature shape memory polymers with fast response time and recyclable performance is highly desired. In this study, a new semi-aromatic tri-amine (TRIA) containing thioether unit is prepared through the reaction of trifluoro-monomer and p-mercaptoaniline (p-MA). It is conducted to polymerize with 4,4′-thiodibenzoyl chloride (TDC) and different ratios of diamine (both of them contained flexible thioether group) to supply a series of slightly crosslinking semi-aromatic polyamide. It is found that the resultant polymers had excellent thermal properties (Tg, 237.9–245.8 °C, Td, 430.9–436.5 °C) and mechanical properties (tensile strength, 74–100 MPa). Because of the introduction of the large amount of flexible thioether group, the resultant polyamides can be dissolved in some aprotic solvents, and can be processed with solution method to fabricate a series of fast-responsive shape memory film (SMF) with a responsive time of 6–8 s, recovery rate of 98–99.5% after 20 cycles. What's more, the oxidized film can even lift a weight equal to about 2–3 times (vertical direction) and 5–8 times (horizontal direction) of its own weight. Interestingly, unlike other shape memory polymers, these SMF after multiple processes (after bending-recovery cycle at high temperature) can still be processed repeatedly with a solution route, which supplies a novel and recyclable candidate for excellent performance SMP. It is expected to be used in solar cell wingspan actuator to light the satellite weight.

Although the influence of salinity on the aggregation of anaerobic ammonia oxidation (anammox) granules has been investigated, the mechanism behind its effect remains poorly understood. Herein, the changes in the surface characteristics, extracellular polymeric substance (EPS) components, and EPS surface groups of anammox granules were studied at 0, 15, and 30 g/L NaCl salinity to elucidate this mechanism. The results showed that as the salt concentration in wastewater increased (0, 15, and 30 g/L NaCl), the size of anammox granules decreased (2.85 ± 0.20 mm, 2.17 ± 0.13 mm and 1.75 ± 0.17 mm, respectively), the aggregation index (AI) of sludge decreased (21.3 % ± 1.5 %, 14.6 % ± 0.8 % and 7.1 % ± 0.9 %, respectively), and the ratio of extracellular protein (PN) to extracellular polysaccharide (PS) decreased (8.8, 6.2 and 4.2, respectively). Analysis of the surface free energy of the anammox granules based on extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) curves showed that increasing salinity decreased the zeta potential and hydrophobicity of the sludge but increased the repulsive barrier in the sludge. Fourier transform infrared (FTIR) spectroscopy and three-dimensional excitation emission matrix (3D-EEM) fluorescence spectroscopy showed that increasing salinity decreased the anammox granule hydrophobicity by changing the EPS surface groups, and the reduction in hydrophobicity was not conducing to the aggregation of anammox granules. These results provide further useful guidance for practical applications of the anammox process to saline wastewater treatment.

The decomposition products of GIS basin insulators have characteristic components under four conditions: different defects of GIS basin insulators, cracks and surface discharge of insulation parts inside GIS, abnormal heating of silicon packing basin insulators under steady state current, and particulate discharge of insulation parts. The characteristic components of decomposition products of SULFUR hexafluoride are introduced. Different mechanisms of decomposition products in partial discharge defects and abnormal heating defects were analyzed. The effects of partial discharge defects, abnormal heating defects and adsorbents on the decomposition products were studied.

With laser-induced breakdown spectroscopy (LIBS), the elemental compositions of the room temperature-vulcanized silicone rubber and the high-temperature-vulcanized silicone rubber newly prepared samples were analyzed in this paper. The LIBS spectra showed that carbon (C), oxygen (O), aluminum (Al), silicon (Si), iron (Fe), and zinc (Zn) were contained in the samples, consistent with the energy dispersive X-ray spectroscopy (EDS) results. With scanning electron microscopy (SEM), the micromorphology and the depth of the ablation craters were observed. The craters’ sizes were only about $200\sim 400~\mu \text{m}$ , and there was nearly no difference between the hydrophobicity of the nonablated area and the ablated area, and the static contact angle of the craters was even larger than that of the nonablated area, meaning that the LIBS analysis was almost nondestructive. The depth of the ablation craters showed linearity relationship with the laser pulse number that would help a lot in the in situ analysis. Increasing the laser energy of the shot, the intensity of spectra lines of definite element and the electron number density would increase at the same time. The study result showed that the LIBS would be a promising element analysis technique of silicone rubber especially on line, and the composition of the composites could be clearly observed.

The stabilization of lifted flames involves a complex competition between small-scale mixing and propagation of flame kernels at the base of the flame. Here, the effect of species diffusivity on this stabilization process is explored. For this purpose, a large-eddy simulation (LES)/probability density function (PDF) methodology accounting for differential diffusion is developed. A dynamic model for scalar mixing time-scale is formulated to accurately describe the turbulence-driven mixing of scalars at the small-scales. Autoignition-stabilized H2/N2 lifted turbulent flames in a vitiated coflow burner are chosen as test cases. Detailed chemical kinetics is used along with in situ adaptive tabulation (ISAT) to accelerate the computations. Four configuration test cases are considered: neglecting differential diffusion (Cases 1 and 2), considering differential diffusion (Case 3) and considering differential diffusion but neglecting molecular transport of H and H2 (Case 4). A dynamic model for scalar mixing time-scale appearing in the mixing model is used in Cases 2, 3 and 4, which removes the need to specify the value of model constant. It is found that the lifted flames are very sensitive to differential diffusion. The predictions of major species mass fractions, temperatures and lift-off heights are in good agreement with the experimental data. Further, such agreement could be achieved without changing any boundary conditions. In particular, increased diffusion of species upstream allows ignition kernels to survive turbulent dissipation, causing stabilization to occur upstream. H2 and H are identified as two critical species that play a dominant role in the differential diffusion effect. The model is also able to capture the change in lift-off height with change in coflow temperature. The results show that even in turbulent flames, stabilization of the flame zone can be sensitive to molecular diffusion. In LES computations where a significant part of this diffusion effect is resolved, the use of the enhanced LES/PDF/ISAT approach is seen as a promising approach for capturing the lift-off physics accurately.

Silicon nanowires (SiNWs) with diameter distributions ranging from 80 to 350 nm were prepared by electrochemical reduction of Ni/SiO2 in molten CaCl2. The effect of the content of nickel additives on the morphology of produced silicon was investigated. Large quantities of SiNWs are obtained by the electrochemical reduction of Ni/SiO2 blocks with SiO2 to Ni molar ratio of 20 and 10. Nickel additives repress the growth of irregular branches and promote longitudinal growth of SiNWs. Wire morphologies and surfaces are influenced by the electrolysis temperature. SiNWs become thicker with the increase of the electrolysis temperature. The optimum temperature to prepare single crystal SiNWs with high aspect ratio and extraordinary surface quality seems to be 1173 K. The amorphous layer of the silicon nanowire is thinner compared to the SiNWs obtained from the pure SiO2 pellets. The produced SiNWs show a photoluminescence emission peak at about 758 nm at room temperature. This work demonstrates the potentiality for the electrochemical reduction process to obtain large quantities of SiNWs with high quality. Silicon nanowires (SiNWs) were prepared by the electrochemical reduction of Ni/SiO2 blocks in molten CaCl2. The effects of the content of nickel additives and the electrolysis temperature on the morphology of produced silicon were investigated. Nickel additives promote the oriented growth of SiNWs and the SiNWs become thicker with the increase of electrolysis temperature.

Silicon nanowires (SiNWs) were produced by the electrochemical reduction of porous NiO/SiO 2 blocks ([SiO 2 ]/[NiO]=10 M ratio) in molten CaCl 2 at 1173 K for the first time. NiO additives seed the growth of straight SiNWs. The produced SiNWs have diameter distributions ranging from 60 to 330 nm and outer amorphous layers with thickness about 2.5–3.1 nm. The length of the nanowire can be as long as 30 µm. The high length-to-diameter suggests that silicon is incorporated through the tip of the nanowire. Nano-sized nickel silicide particles are observed in the body of a zigzag SiNW. The results indicate that the electrochemical reduction process has the potential to produce nano-sized Si-based composite and metal silicide.

2,6-bis(N-pyrazolyl) pyridine (BPP) with tridentate N3 group is successfully incorporated into copolymer via solution polycondensation in this work. With assembly of different metal ions, the supramolecules could be shape-memorized or fluorescence-responsive. The tridentate N3 group in BPP fragment is found to enhance the fluorescence intensity of BPP-Eu3+ films and affinity to the metal ions, supported by inter-fragmented charge transfer theory (IFCT) and wavefunction analysis. The heat-resistance of supramolecules is improved by incorporation of zinc ions and the Tg could be changed from 150.5 °C up to 201.7 °C. The average binding strength (BDE) of N–Zn2+ in NMP solvation model is −5.03 kcal/mol, which is flexible enough to maintain the dynamic properties discussed in this study.

With the increasing researches on the role of gut microbiota in human health and disease, appropriate storage method of fecal samples at ambient temperature would conveniently guarantee the precise and reliable microbiota results. Nevertheless, less choice of stabilizer that is cost-efficient and feasible to be used in longer preservation period obstructed the large-scale metagenomics studies. Here, we evaluated the efficacy of a guanidine isothiocyanate-based reagent method EffcGut and compared it with the other already used storage method by means of 16S rRNA gene sequencing technology. We found that guanidine isothiocyanate-based reagent method at ambient temperature was not inferior to OMNIgene·GUT OM-200 and it could retain the similar bacterial community as that of −80 °C within 24 weeks. Furthermore, bacterial diversity and community structure difference were compared among different sample fraction (supernatant, suspension and precipitate) preserved in EffcGut and −80 °C. We found that supernatant under the preservation of EffcGut retained the similar community structure and composition as that of the low temperature preservation method.

Layered nanocomposite hydrotalcite/montmorillonite (LDH/MMT) was obtained though in-situ synthesis of nickel-magnesium-aluminum hydrotalcite (Ni-Mg-Al LDH) on the surface of montmorillonite nanosheets (MMTNS) by one-step hydrothermal method. X-ray diffractometer (XRD), Fourier Transform Infrared Spectrometer (FTIR), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) were used to characterize the composite material. The flame retardancy property of the composite was investigated by thermogravimetry (TG) and cone calorimeter (Cone). The results show that both the hydrotalcite and montmorillonite nanosheets have a lamellar structure; LDH/MMT composite has better thermal stability than that of hydrotalcite or montmorillonite alone, and the flame retardant effect of LDH/MMT on polystyrene (PS) is more obvious. The composite material can reduce the maximum heat release rate of polystyrene during combustion by 14.8%.

Prenyltransferase NovQ immobilized carboxymethyl cellulose magnetic nanoparticles (NCMNs) were successfully synthesized via a valuable approach integrated from nanocomposite preparation, and applied for the production of vitamin K2 using menadione hydroquinol and dimethylallyl diphosphate (DMAPP) as substrates. To investigate the interaction between nanoparticles and NovQ, we characterized the nanocomposite, and revealed that carboxymethyl cellulose (CMC) and Fe3O4 formed a core-shell structure to absorb NovQ in the reaction systems, resulting from the high affinity of immobilized materials. Meanwhile, NCMNs with excellent pH and temperature tolerance, enhanced prenylated activity, and improved stability were found. Molecular docking analysis was also conducted to justify the contribution of multiple amino acids and effect of nanoparticles on catalytic properties of NovQ. Taken together, our study introduces a promising strategy to prepare magnetic nanoparticles and improve the performance of catalyst, which aims for opening new orientations for synthesis of magnetic nanoparticles used for prenyltransferase immobilization.