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Soybean oil is composed of fatty acids and glycerol. The content and composition of fatty acids partly determine the quality of soybean seeds. Circular RNAs (circRNAs) are endogenous non-coding RNAs that competitively bind to microRNAs (miRNAs) through miRNA recognition elements, thereby acting as sponges to regulate the expression of target genes. Although circRNAs have been identified previously in soybean, only their expression has been investigated without exploration of the competitive endogenous RNAs (ceRNAs) network of circRNAs-miRNAs-mRNAs. In this study, circRNAs in immature pods of a low linolenic acid soybean Mutant 72' (MT72) and the wild-type control 'Jinong 18' (JN18) were systematically identified and analyzed at 30 and 40 days after flowering using high-throughput sequencing technology. We identified 6377 circRNAs, of which 114 were differentially expressed. Gene ontology and KEGG pathway analyses of targeted mRNAs in the ceRNAs network indicated that the differentially expressed circRNAs may be involved in fatty acid transport, suggesting that circRNAs may play a post-transcriptional regulatory role in soybean oil synthesis. This study provides a foundation for future exploration of the function of circRNAs in soybean and presents novel insights to guide further studies of plant circRNAs.

Controllable regulation of stem cell differentiation is a critical concern in stem cell-based regenerative medicine. In particular, there are still great challenges in controlling the directional differentiation of neural stem cells (NSCs) into neurons. Herein, we developed a novel linear-branched poly(

Long non-coding RNAs (lncRNAs) are non-coding RNAs of more than 200 nucleotides. To date, the roles of lncRNAs in soybean fatty acid synthesis have not been fully studied. Here, the low-linolenic acid mutant ‘MT72′ and the wild-type control ‘JN18′ were used as materials. The lncRNAs in young pods at 30 and 40 days (d) after flowering were systematically identified and analyzed using transcriptome sequencing technology combined with bioinformatics tools. A total of 39,324 lncRNAs and 561 differentially expressed lncRNAs were identified. A lncRNAs-miRNAs-protein-coding genes (mRNAs) network was constructed, and 46 lncRNAs, 46 miRNAs and 137 mRNAs were found to be correlated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of 12 targeted mRNAs in the competing endogenous RNA network showed that these lncRNAs may be involved in the biological processes of fatty acid transport, lipid synthesis and cell division. Finally, the expression levels of differentially expressed lncRNAs, miRNAs and mRNAs were verified using qRT-PCR. The expression patterns of most genes were consistent with the sequencing results. In conclusion, new information was provided for the study of fatty acid synthesis by lncRNAs in young soybean pods.

Controllable regulation of stem cell differentiation is a critical concern in stem cell-based regenerative medicine. In particular, there are still great challenges in controlling the directional differentiation of neural stem cells (NSCs) into neurons. Herein, we developed a novel linear-branched poly(β-amino esters) (S4-TMPTA-BDA-DT, STBD) through a two-step reaction. The synthesized linear-branched polymers possess multiple positively charged amine terminus and degradable intermolecular ester bonds, thus endowing them with excellent properties such as high gene load, efficient gene delivery, and effective gene release and transcription in cells. In the mCherry transfection test, a high transfection efficiency of approximately 70% was achieved in primary NSCs after a single transfection. Moreover, STBD also showed high biocompatibility to NSCs without disturbing their viability and neural differentiation. With the high gene delivery property, STBD is capable of delivering siRNA (shSOX9) expression plasmid into NSCs to significantly interfere with the expression of SOX9, thus enhancing the neuronal differentiation and maturation of NSCs. The STBD/DNA nano-polyplex represents a powerful non-viral approach of gene delivery for manipulating the differentiation of stem cells, showing broad application prospects in NSC-based regenerative therapy for treating neurodegenerative diseases.

The effect of SiO2 addition on phase transition, microstructure and microwave dielectric properties of α-CaSiO3 ceramics was reported for the first time. The X-ray diffraction analysis confirmed that the phase transformation from cyclo-CaSiO3 to pseudo-CaSiO3 was inhibited with the increase of SiO2 content. It was observed that the average grain size decreased with the increasing addition of SiO2 by scanning electron microscope. The τ f of the SiO2-added α-CaSiO3 ceramics almost remained constant with the SiO2 content increased, while the e r and Q × f changed obviously. The optimized properties were determined for SiO2 6 wt% additive α-CaSiO3 ceramics sintered at 1,350 °C: e r = 7.37, Q × f = 33,714 GHz and τ f = −11.08 ppm/°C.

Gelled hypergolic propellants offer potential safety and performance improvements over conventional liquid and solid propellants. Understanding the combustion process of single gelled droplets is the first basic step to predict their behavior in the future combustion chambers. Experimental studies were performed to investigate the burning behavior of gelled unsymmetrical dimethylhydrazine (UDMH) droplets under oxidant convective conditions. The effects of oxidant convective conditions including velocity and temperature on the burning behavior were analyzed. The burning process was broken down into four stages: heating and swelling period, initial combustion period, violent combustion period, and stable and extinguished combustion period. Sometimes the droplet inside seemed to be porous or botryoidal. The microexplosion period lasted for a long time sometimes exceeding about 70% of the burning lifetime, and the phenomenon of gas jet combustion due to the burst steam from microexplosions was founded. The conversion of burning flame from a layered and enveloped flame structure to an escaped flame structure with increase in the convective velocity was observed. When the enveloped flame appeared, it was more helpful to the burning process, and the intensity of microexplosions and the burning rate constant were found to increase with the convective temperature. When the escaped flame appeared, it was disadvantageous to the burning process, and the intensity of microexplosions decreases with rise in convective velocity. Compared with the escaped flame, the intensity of microexplosions of the enveloped flame was lower, but the frequency was higher.

It is widely accepted that nonmetalized organic gel fuel droplets exhibit characteristic and complicated oscillations during both evaporation and combustion, in contrast to the quasi-steady combustion of conventional liquid droplets. In this paper, an unsteady combustion model for the gel droplet is developed, taking into consideration the interactions between oscillating evaporation and flame structures. This model is first validated against experimental results for droplets of an organic gel based on unsymmetrical dimethylhydrazine (UDMH) burning in various nitrogen tetroxide (NTO) oxidizing atmosphere. Using this newly derived model and a detailed UDMH/NTO gas phase chemical reaction mechanism, the combustion characteristics of spray-sized UDMH gel droplets are numerically simulated and discussed in detail. The simulation and experimental results for droplet diameter and temperature both exhibit the same trend during the combustion process. The simulation error for droplet lifetime increases with both droplet size and ambient pressure as a consequence of neglecting heat conduction of the suspending thread and nonideal gas behavior in the model. Numerical simulation results for the detailed flow field parameter variations of the spray-size gel droplet combustion show obvious oscillations in both droplet radius and UDMH vapor mass fraction at the droplet surface following the formation of a gellant film. The oscillation frequency gradually decreases as the film thickness increases and the fuel is depleted. Although the double-flame temperatures and their standoff ratios also oscillate as the gellant film swells and ruptures, their relative oscillation amplitudes are smaller than those of the droplet radius and the vapor mass fraction at the droplet surface. The temperature of the gas phase flow field is higher when fuel vapor at the droplet surface is more abundant, but there is usually a time lag between the gas phase temperature reaching its maximum and the gellant film bursting within each swell-burst period because of the finite fuel vapor diffusion velocity. The temperature of the droplets continues to rise even after reaching the boiling point of liquid UDMH, since the boiling of the relatively small amount of liquid UDMH in a spray droplet cannot absorb all the heat flux from the flame.

[Abstract] The present study is focused on measuring the atomization and combustion behavior of gelled propellant. The main aim is to examine the characteristics of the flame structure, the spray breakup length and the spray angle of gelled droplets at different initial chamber conditions and initial spray parameters. Results show that the gelled liquid ligament burns up quickly after only about 0.0099 sec at a certain condition. The gelled liquid ligament burns up more quickly than a gelled droplet. Additionally, the injected velocity and the width of gelled liquid ligament have an influence on the burning time. The spraying ligament would be shrunk and a droplet separated from the liquid ligament during the burning process.

Surface dielectric barrier discharge (SDBD) is a promising method for a flow control. Flow fields induced by a SDBD actuator driven by the ac voltage in static air at low pressures varying from 1.0 to 27.7 kPa are measured by the particle image velocimetry method. The influence of the applied ac voltage frequency and magnitude on the induced flow fields is studied. The results show that three different classes of flow fields (wall jet flow field, complex flow field, and vortex-shape flow field) can be induced by the SDBD actuator in the low-pressure air. Among them, the wall jet flow field is the same as the tangential jet at atmospheric pressure, which is, together with the vertical jet, the complex flow field. The vortex-shape flow field is composed of one vertical jet which points towards the wall and two opposite tangential jets. The complex and the vortex-shape flow fields can be transformed to the wall jet flow field when the applied ac voltage frequency and magnitude are changed. It is found that the discharge power consumption increases initially, decreases, and then increases again at the same applied ac voltage magnitude when the air pressure decreases. The tangential velocity of the wall jet flow field increases when the air pressure decreases. It is however opposite for the complex flow field. The variation of the applied ac voltage frequency influences differently three different flow fields. When the applied ac voltage magnitude increases at the same applied ac voltage frequency, the maximal jet velocity increases, while the power efficiency increases only initially and then decreases again. The discharge power shows either linear or exponential dependences on the applied ac voltage magnitude.