Highly secretory expression of recombinant cowpea chlorotic mottle virus capsid proteins in Pichia pastoris and in-vitro encapsulation of ruthenium nanoparticles for catalysis

The applications of viral protein cages have expanded rapidly into the fields of bionanotechnology and materials science. However, the low-cost production of viral capsid proteins (CPs) on a large scale is always a challenge. Herein, we develop a highly efficient expression system by constructing recombinant Pichia pastoris cells as a “factory” for the secretion of soluble cowpea chlorotic mottle virus (CCMV) CPs. Under optimal induction conditions (0.9 mg/mL of methanol concentration at 30 °C for 96 h), a high yield of approximately 95 mg/L of CCMV CPs was harvested from the fermentation supernatant with CPs purity >90%, which has significantly simplified the rest of the purification process. The resultant CPs are employed to encapsulate Ruthenium (Ru) nanoparticles (NPs) via in-vitro self-assembly to prepare hybrid nanocatalyst, i.e. Ru@virus-like particles (VLPs). The catalytic activity over Ru@VLPs was evaluated by reducing 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The results indicate that, with the protection of protein cages, Ru NPs were highly stabilized during the catalytic reaction. This results in enhanced catalytic activity (reaction rate constant k = 0.14 min−1) in comparison with unsupported citrate-stabilized Ru NPs (Ru-CA) (k = 0.08 min−1). Additionally, comparatively lower activation energy over Ru@VLPs (approximately 32 kJ/mol) than that over Ru-CA (approximately 39 kJ/mol) could be attributed to the synergistic effect between Ru NPs and some functional groups such as amino groups (–NH2) on CPs that weakened the activation barrier of 4-NP reduction. Therefore, enhanced activity and decreased activation energy over Ru@VLPs demonstrated the superiority of Ru@VLPs to unsupported Ru-CA

Investigation on Aerodynamic Noise Characteristics of Coaxial Rotor in Hover

A numerical method based on Reynolds Averaged Navier–Stokes (RANS) equations and a high-efficiency trim model is developed to simulate the aerodynamics of a coaxial rotor. Farassat 1A equations are used for the prediction of thickness and loading noise. Hover cases of different thrust coefficients with torque balance are conducted. The sound pressure history of different observation points positioned below the rotor disk plane is analyzed. Results indicate that the special noise characteristics of the coaxial rotor are mainly caused by the noise superposition of the twin rotors and the unsteady loads of aerodynamic interaction. A new kind of impulsive loading noise is induced by the blade-meeting interaction. In contract to the single rotor, the loading noise of a coaxial rotor has a much larger sound pressure level in the high-frequency band. The loading noise is obviously enhanced around the blade-meeting azimuths. The maximum noise of the coaxial rotor is located immediately below the rotor disk center, while for the single rotor, it is the minimum location

Study on Joint Connection Performance of an Innovative Tooth Groove Connection and Vertical Reinforcement Lapping in Reserved Hole

In order to explore the horizontal joint connection performance of the innovative tooth groove connection and vertical reinforcement lapping in the reserved hole, five horizontal joint specimens were designed and constructed in this paper. Through the combination of monotonic horizontal load tests and finite element simulation analysis, the effects of axial compression ratio, vertical reinforcement connection degree, reserved hole type, mortar strength, and tooth groove depth on the horizontal joint connection performance of innovative tooth groove connections and vertical reinforcement lapping in reserved holes were comprehensively analyzed and discussed. The results indicated that the specimens were subjected to penetration failure at the tooth groove joint, but the vertical reinforcements and UHPC in reserved holes can effectively transfer the stress, ensuring satisfactory connection performance. With the increase in axial compression ratio and vertical reinforcement connection degree, the joint connection performance enhanced gradually, while the reserved hole type had little effect on the joint connection performance. In addition, it was found that increasing the mortar strength and the tooth groove depth can significantly improve the peak bearing capacity through finite element analysis. Finally, the optimization design suggestions for this innovative tooth groove connection and vertical reinforcement lapping in the reserved hole were given considering factors such as joint connection performance and construction assembly

Investigation on Aerodynamic Noise Characteristics of Coaxial Rotor in Hover

A numerical method based on Reynolds Averaged Navier–Stokes (RANS) equations and a high-efficiency trim model is developed to simulate the aerodynamics of a coaxial rotor. Farassat 1A equations are used for the prediction of thickness and loading noise. Hover cases of different thrust coefficients with torque balance are conducted. The sound pressure history of different observation points positioned below the rotor disk plane is analyzed. Results indicate that the special noise characteristics of the coaxial rotor are mainly caused by the noise superposition of the twin rotors and the unsteady loads of aerodynamic interaction. A new kind of impulsive loading noise is induced by the blade-meeting interaction. In contract to the single rotor, the loading noise of a coaxial rotor has a much larger sound pressure level in the high-frequency band. The loading noise is obviously enhanced around the blade-meeting azimuths. The maximum noise of the coaxial rotor is located immediately below the rotor disk center, while for the single rotor, it is the minimum location

17β-estradiol modulates the viability, phenotype, endocytosis, and inflammatory cytokine expression of RAW264.7 macrophages

17β-estradiol (E2) is a female sex steroid hormone and exerts a pivotal role not only in female pregnancy but also in organ immune responses. Macrophages, as a kind of antigen-presenting cells, play an important influence on the cellular and humoral immune responses and also express the E2 receptor. In the present study, we explored the effects of E2 on the viability, endocytosis, surface molecule, and inflammatory cytokine expression of RAW264.7 macrophages. Results showed that E2 slightly increased the cell proliferation and endocytosis of RAW264.7 cells, while notably decreasing the mRNA and protein levels of inflammatory cytokines such as tumor necrosis factor (TNF)-α and monocyte chemoattractant protein-1 (MCP-1). As for the expression of surface molecules closely associated with the functions of macrophages, E2 significantly reduced the levels of CD40, CD80, and MHC-II. Interestingly, E2 reduced the levels of CD86 at low dose (10 nM and 1 nM), while enhancing its expression at high doses (1 μM and 0.1 μM). These results suggest that E2 may play an immuno-suppressive role in the inflammatory reactions and some autoimmune diseases partly by influencing the expressions of some important surface molecules and inflammatory cytokines of macrophages

Efficient Synthesis of Furfural from Corncob by a Novel Biochar-Based Heterogeneous Chemocatalyst in Choline Chloride: Maleic Acid–Water

The use of plentiful and renewable feedstock for producing chemicals is fundamental for the development of sustainable chemical processes. Using fish scale as a biobased carrier, a novel biochar SO42−/SnO2-FFS heterogeneous chemocatalyst was prepared to catalyze furfural production from xylose-rich corncob-hydrolysates obtained from acid hydrolysis of corncob in a deep eutectic solvent (DES)–water system. By characterizing the physical as well as chemical properties of SO42−/SnO2-FFS by NH3-TPD, FT-IR, XPS, XRD, and SEM, it was shown that the chemocatalyst had Lewis/Brönsted acid centers, and its surface roughness could be well expanded to contact substrates. The corncob was initially hydrolyzed at 140 °C to obtain xylose-rich hydrolysate. Subsequently, SO42−/SnO2-FFS (3.6 wt.%) was used to catalyze the corn cob hydrolysate containing D-xylose (20.0 g/L) at a reaction temperature of 170 °C for 15 min. Additionally, ZnCl2 (20.0 g/L) was added. Ultimately, furfural (93.8 mM, 70.5% yield) was produced in the deep eutectic solvent ChCl:maleic acid–water (DESMLA–water = 10:90, v/v). A synergistic catalytic mechanism for transforming xylose-rich corncob-hydrolysate into furfural and byproducts were proposed using SO42−/SnO2-FFS as a chemocatalyst in DESMLA–water containing ZnCl2. Consequently, the efficient use of biochar SO42−/SnO2-FFS chemocatalysts for the sustainable synthesis of biobased furan compounds from biomass holds great promise in the future

Study of Single Phase Mass Transfer between Matrix and Fracture in Tight Oil Reservoirs

In tight fractured reservoirs, oil in matrices is mainly explored due to mass transfer mechanisms during the pressure depletion process. In the modeling of mass transfer in fractured reservoirs using the dual porosity concept, the shape factor is the most important parameter and should be described accurately. However, the current shape factors are not suited for tight oil reservoir simulation because the characteristics of tight oil reservoirs are not taken into account. In order to solve this problem, a new mass transfer function for tight fractured oil reservoirs is proposed by introducing a new time-related correction factor which could consider not only the existence of the boundary layer in nano-microscale throats in tight porous media but also the heterogeneous pressure distribution in matrix blocks. In addition, special contact relations between matrix and fracture are included. The correction factor presented in this study is verified using the experimental data and numerical simulation results. Data analysis results demonstrate that the lower and slower the pressure propagation velocity, the longer the duration time of unsteady flow compared to conventional reservoirs. Therefore, in the calculation of mass transfer flow in tight oil reservoirs, the unsteady flow between fracture and matrix cannot be ignored

Dispersibility of Kaolinite-Rich Coal Gangue in Rubber Matrix and the Mechanical Properties and Thermal Stability of the Composites

The aim of this work was to investigate the dispersibility of kaolinite-rich coal gangue in rubber matrix, the mechanical properties and thermal stability of coal gangue/styrene butadiene rubber (SBR) composites, and to compare these properties to those of the same coal gangue but had undergone thermal activation and modification. Several experimental techniques, such as X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric-differential scanning calorimetry (TG-DSC), laser-scattering particle analyzer were adopted to characterize the coal gangue particles and then the obtained composites. The results demonstrated the raw coal gangue (RCG) was mainly composed of kaolinite. Calcination led to amorphization of thermal activated coal gangue (ACG), increased hydrophilicity and void volume, and decreased pH. The grain size of ACG became coarser than RCG, but ACG turned loose confirmed by higher degree of refinement after grinding. Modification enhanced the hydrophobicity of the coal gangue and improved its dispersibility than fillers without modification. Calcined samples had better dispersibility than uncalcined fillers. Additionally, the coal gangue treated by calcinating, grinding and modifying (MGA) had the best dispersion in rubber matrix. Either calcination or modification could improve the mechanical properties and thermal stability of coal gangue filled rubber, while the performance of MGA reinforced SBR (MGA-SBR) was the best. The enhanced performance of the MGA-SBR was owed to better dispersion of particles as well as stronger interactions between particles and rubber macromolecules

Dispersibility of Kaolinite-Rich Coal Gangue in Rubber Matrix and the Mechanical Properties and Thermal Stability of the Composites

The aim of this work was to investigate the dispersibility of kaolinite-rich coal gangue in rubber matrix, the mechanical properties and thermal stability of coal gangue/styrene butadiene rubber (SBR) composites, and to compare these properties to those of the same coal gangue but had undergone thermal activation and modification. Several experimental techniques, such as X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric-differential scanning calorimetry (TG-DSC), laser-scattering particle analyzer were adopted to characterize the coal gangue particles and then the obtained composites. The results demonstrated the raw coal gangue (RCG) was mainly composed of kaolinite. Calcination led to amorphization of thermal activated coal gangue (ACG), increased hydrophilicity and void volume, and decreased pH. The grain size of ACG became coarser than RCG, but ACG turned loose confirmed by higher degree of refinement after grinding. Modification enhanced the hydrophobicity of the coal gangue and improved its dispersibility than fillers without modification. Calcined samples had better dispersibility than uncalcined fillers. Additionally, the coal gangue treated by calcinating, grinding and modifying (MGA) had the best dispersion in rubber matrix. Either calcination or modification could improve the mechanical properties and thermal stability of coal gangue filled rubber, while the performance of MGA reinforced SBR (MGA-SBR) was the best. The enhanced performance of the MGA-SBR was owed to better dispersion of particles as well as stronger interactions between particles and rubber macromolecules

Método de calibración del horizonte subterráneo de petróleo basado en la gravedad de alta precisión y la exploración magnética

Because the high-precision calibration results of the petroleum underground layer are of great significance for oil production efficiency, research on the calibration method of the petroleum underground layer based on high precision gravity and magnetic exploration is researched. The gravity magnetic model is used to retrieve the bedrock depth, and the results of the basement structure and sedimentary rock distribution of the gravity and magnetic geology in the petroleum underground horizon of the Tongbai basin are obtained. On this basis, the geological data, logging data, seismic data, and VSP data are comprehensively used, and the layered calibration method is used to calibrate the petroleum underground layer of the Tongbai basin. Considering the seismic datum and the core elevation in the area, the rock formation is divided by various logging curves. The average time difference and density of the divided rock layers are interpolated at equal depth intervals to obtain velocity sequences and density sequences at equal time intervals and finally realize time-depth conversion. When the drilling geological horizon is unified, the synthetic record of the seismic reflection layer is compared with the geological horizon to realize the horizon calibration of the seismic reflection layer. When the local stratification is not uniform, the seismic reflection layer is calibrated by tracking the seismic reflection layer, high-precision velocity analysis, and various synthetic records to verify the reliability of the geological horizon. The results show that the proposed method can accurately survey the geological conditions of the Tongbai basin. It detected 14 basement faults, and the NW-trending and NE-trending faults controlled the basin, while the north-south faults controlled the later evolution of the basin. The method can be used for the horizon calibration of inclined wells, which is suitable not only for anisotropic media but also for formations with a less lateral variation of local formation lithology. Moreover, its usage is flexible, and it can be corrected by multiple speed data.Debido a que los resultados de calibración de alta precisión de la capa subterránea de petróleo son de gran importancia para la eficiencia de la producción de petróleo, se investiga la investigación sobre el método de calibración de la capa subterránea de petróleo basada en la gravedad de alta precisión y la exploración magnética. El modelo magnético de gravedad se utiliza para recuperar la profundidad de la roca madre, y se obtienen los resultados de la estructura del sótano y la distribución de rocas sedimentarias de la gravedad y la geología magnética en el horizonte subterráneo de petróleo de la cuenca tongbai. Sobre esta base, los datos geológicos, los datos de registro, los datos sísmicos y los datos VSP se usan de manera integral, y el método de calibración en capas se usa para calibrar la capa subterránea de petróleo de la cuenca tongbai. Teniendo en cuenta el dato sísmico y la elevación del núcleo en el área, la formación rocosa se divide por varias curvas de registro. La diferencia de tiempo promedio y la densidad de las capas de roca divididas se interpolan a intervalos de profundidad iguales para obtener secuencias de velocidad y secuencias de densidad a intervalos de tiempo iguales, y finalmente realizar la conversión de profundidad de tiempo. Cuando el horizonte geológico de perforación se unifica, el registro sintético de la capa de reflexión sísmica se compara con el horizonte geológico para realizar la calibración del horizonte de la capa de reflexión sísmica. Cuando la estratificación local no es uniforme, la capa de reflexión sísmica se calibra siguiendo la capa de reflexión sísmica, el análisis de velocidad de alta precisión y varios registros sintéticos para verificar la fiabilidad del horizonte geológico. Los resultados muestran que el método propuesto puede estudiar con precisión las condiciones geológicas de la cuenca tongbai. Detectó 14 fallas en el sótano, y las fallas de tendencia NW y NE controlaron la cuenca, mientras que las fallas norte-sur controlaron la evolución posterior de la cuenca. El método puede usarse para la calibración del horizonte de pozos inclinados, que es adecuado no solo para medios anisotrópicos, sino también para formaciones con menor variación lateral de la litología de formación local. Además, su uso es flexible y puede corregirse con múltiples datos de velocidad