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With the aim of effectively removing tannin from Rosa roxburghii juice, reducing astringency, and enhancing its taste, chemical precipitation was applied, and ginger protein was used as the tannin remover. Besides, tannin removal rate and vitamin C (VC) retention rate were adopted as the key analytical parameters. In addition, single-factor experiment and orthogonal test were used to determine the optimal tannin removal process for ginger protein. The results were as follows: (1) The optimal conditions for removing tannin from R. roxburghii juice with ginger protein were a liquid-solid ratio of 30∶1.2 (mL∶g), R. roxburghii juice pH of 3.0, a stirring temperature of 5 ℃, and a stirring time of 30 min. (2) According to orthogonal test analysis, the degree of influence of various factors on removing tannin from R. roxburghii juice was liquid-solid ratio > stirring temperature > R. roxburghii juice pH > stirring time. (3) Under the optimal process conditions, the tannin removal rate and VC retention rate were (47.451±0.608)% and（75.904±1.244）% respectively. (4) Under the optimal process conditions, juice transmittance rate increased from (8.44±0.662)% to (92.47±0.397)%, the astringency of R. roxburghii juice was significantly reduced, and its flavor was improved. In summary, this study provides a novel approach and a new technological route for solving common key technical problems faced by the deep processing industry of R. roxburghii juice and also provides a certain technical reference for exploiting ginger resources comprehensively.

This work aimed to investigate combustion mode conversions by rapid variation of the fuel flow rate in a cavity-based scramjet combustor. The experiments were carried out on a direct-connected facility with an inflow condition of Mach number 2.52, a total pressure of 1.35 MPa, and a total temperature of 1650 K. The fuel injector consisted of two injection ports: fuel was continuously injected from one port while the other controlled the fuel flow for mode conversions by switching it on or off. Simultaneous schlieren and CH* imaging techniques were used to characterize the dynamics of combustion mode conversions. It was recognized that the combustion modes characterized by different flow field structures and heat release distributions can be classified into three types: the shear-layer mode, the transition mode, and the jet-wake mode. During the combustion mode conversion, the mixing region of the transverse jet and air became thicker with the increase in fuel flow rate, and the gradient of the flow field density and the flame area increased, making the flame more likely to propagate upstream. The combustion suppression induced by rapid fuel addition was observed at low equivalence ratios. It was speculated that the weak heat supply was insufficient to provide adequate heat for the rapid ignition of the added fuel. Furthermore, it was found that the flame-flow matching process with frequent flame propagation upstream occurred during the combustion mode conversion. This process was attributed to the mismatch between the increasing heat release and the original flow field structure. [ABSTRACT FROM AUTHOR]

Summary: Gene silencing is crucial in crop breeding for desired trait development. RNA interference (RNAi) has been used widely but is limited by ectopic expression of transgenes and genetic instability. Introducing an upstream start codon (uATG) into the 5′untranslated region (5′UTR) of a target gene may 'silence' the target gene by inhibiting protein translation from the primary start codon (pATG).Here, we report an efficient gene silencing method by introducing a tailor‐designed uATG‐containing element (ATGE) into the 5′UTR of genes in plants, occupying the original start site to act as a new pATG.Using base editing to introduce new uATGs failed to silence two of the tested three rice genes, indicating complex regulatory mechanisms. Precisely inserting an ATGE adjacent to pATG achieved significant target protein downregulation. Through extensive optimization, we demonstrated this strategy substantially and consistently downregulated target protein expression. By designing a bidirectional multifunctional ATGE4, we enabled tunable knockdown from 19% to 89% and observed expected phenotypes. Introducing ATGE into Waxy, which regulates starch synthesis, generated grains with lower amylose, revealing the value for crop breeding.Together, we have developed a programmable and robust method to knock down gene expression in plants, with potential for biological mechanism exploration and crop enhancement. See also the Commentary on this article by Li & Wei, 243: 2052–2054. [ABSTRACT FROM AUTHOR]

A study published in the Journal of Integrative Plant Biology introduces a new rice guanine base editor (OsGTBE) that allows for targeted and efficient G-to-T editing in rice. The researchers used OsGTBE to edit herbicide-resistant loci, resulting in the creation of new alleles that confer herbicide resistance. This base editor expands the range of editing products in plants and has the potential to enhance genetic diversity and create valuable germplasm. The document provides a list of primers and oligos used in a related study, which may be useful for library patrons conducting research in related fields. [Extracted from the article]

The ignition and flame propagation in an axisymmetric supersonic combustor were investigated. The laser-induced plasma was employed to ignite the supersonic inflow with a speed of Mach 2.5 and a total temperature of 1486 K. A direct-connect axisymmetric model scramjet with a fully transparent glass combustor was built, which enabled the circumferential and axial flame propagation in the cavity-based axisymmetric supersonic combustor to be visualized by the high-speed photography from the endoscopic and external views, respectively. An initial flame kernel is produced by the laser-induced plasma and propagates to the cavity leading edge along the axial direction. The establishment of the cavity shear-layer flame facilitates circumferential flame propagation. The circumferential flame propagation is coupled with the axial propagation, eventually generating a loop-shaped flame with a central-hole. Acceleration of the flame propagation can be observed, especially when the global equivalence ratio is increased. A plausible explanation for the flame propagation in the axisymmetric supersonic combustor was found using URANS numerical simulation. The axisymmetric cavity generates a low-speed loop-shaped recirculation region and thickened cavity shear-layer with an appropriate local equivalence ratio, resulting in the simultaneous axial and circumferential flame propagation. The increased temperature in the cavity and the thickened cavity shear-layer during the flame propagation produce a more intense heat release and mass transfer, leading to faster flame propagation. [ABSTRACT FROM AUTHOR]

Plasma-assisted combustion (PAC) has shown excellent performance in the ignition and combustion enhancement of scramjet combustors. A multi-channel gliding arc (MCGA) plasma placed on the sidewall surface of a scramjet combustor was employed to enhance combustion near the flame blowout limit (BL) in a C 2 H 4 -fueled and cavity-based model scramjet combustor. Wall static pressure measurements, simultaneous 10 kHz CH* chemiluminescence imaging from the top and side views, optical emission spectroscopy, and discharge waveform measurements were used to elucidate the combustion physics throughout the PAC events. For the current cavity configuration and fueling condition, a general estimate of the flame BL in a rich-fuel environment was provided, in which a fuel flow rate (FFR) was 7.5 g/s. Once the FFR was exceeded, the flame was unstable and blown out, whereas the MCGA plasma demonstrated an excellent flame stabilization ability. The flame BL of the scramjet combustor in the presence of the MCGA plasma has an increase of ∼29%. Two PAC processes, including enhancement mode and re-ignition mode, were distinguished to play a vital role in extending the flame BL. The two PAC processes showed that the spark-type discharge generated by the MCGA could ignite the local fuel-rich mixture and increase the flame BL. The local ignition is dominated by the continuous accumulation of the massive flame kernels with the local fuel-rich mixture, as well as more heat and species exchanges. [ABSTRACT FROM AUTHOR]

With the widespread use of clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR‐associated nuclease (Cas) technologies in plants, large‐scale genome editing is increasingly needed. Here, we developed a geminivirus‐mediated surrogate system, called Wheat Dwarf Virus‐Gate (WDV‐surrogate), to facilitate high‐throughput genome editing. WDV‐Gate has two parts: one is the recipient callus from a transgenic rice line expressing Cas9 and a mutated hygromycin‐resistant gene (HygM) for surrogate selection; the other is a WDV‐based construct expressing two single guide RNAs (sgRNAs) targeting HygM and a gene of interest, respectively. We evaluated WDV‐Gate on six rice loci by producing a total of 874 T0 plants. Compared with the conventional method, the WDV‐Gate system, which was characterized by a transient and high level of sgRNA expression, significantly increased editing frequency (66.8% vs. 90.1%), plantlet regeneration efficiency (2.31‐fold increase), and numbers of homozygous‐edited plants (36.3% vs. 70.7%). Large‐scale editing using pooled sgRNAs targeting the SLR1 gene resulted in a high editing frequency of 94.4%, further demonstrating its feasibility. We also tested WDV‐Gate on sequence knock‐in for protein tagging. By co‐delivering a chemically modified donor DNA with the WDV‐Gate plasmid, 3xFLAG peptides were successfully fused to three loci with an efficiency of up to 13%. Thus, by combining transiently expressed sgRNAs and a surrogate selection system, WDV‐Gate could be useful for high‐throughput gene knock‐out and sequence knock‐in. [ABSTRACT FROM AUTHOR]