R3-MYB proteins OsTCL1 and OsTCL2 modulate seed germination via dual pathways in rice

Salt and drought stress are common abiotic factors that exert a detrimental influence on seed germination,potentially leading to significantly impaired growth and production in rice.Gaining a comprehensive understanding of the molecular response of seeds to abiotic stress during the germination is of paramount importance.In the present study,we identified two R3-MYB genes in rice,namely OsTCL1 and OsTCL2,and characterized their roles in regulating seed germination under salt and drought stress.Plants with tcl1 and tcl2 mutant alleles exhibited delayed seed germination,particularly under stress conditions.The tcl1 tcl2 double mutant showed an even more pronounced reduction in germination during initial stages of germination,thereby indicating a redundant regulatory function of OsTCL1 and OsTCL2 in seed germination under abiotic stresses.Furthermore,we demonstrated that the transcript levels of several phospholipase D(PLD)genes were downregulated in the tcl1 tcl2 mutant,resulting in a decreased level of the phosphatidic acid(PA)product.Application of 1-butanol,a competitive substrate inhibitor of PLD-dependent production of PA,attenuated the stress response of the tcl1 tcl2 mutant.This suggests that OsTCL1 and OsTCL2 partially modulate seed germination through the PLD-PA signaling pathway.Moreover,there were alterations in the expression of genes involved in abscisic acid(ABA)biosynthesis,metabolism and signaling transduction in the double mutant.These changes affected the endogenous ABA level and ABA response,thereby influencing seed germination.Application of both 1-butanol and ABA synthesis inhibitor sodium tungstate(Na2WO4)nearly eliminated the differences in stress response between wild type and the tcl1 tcl2 mutant.This indicates that OsTCL1 and OsTCL2 synergistically coordinate seed germination under abiotic stresses through both the PLD-PA signaling and ABA-mediated pathways.

以培养自我调节学习能力为导向的分析化学实验混合教学模式

为探索合适的教学模式以培养自我调节学习为基础的终身学习能力,在分析化学实验的教学中,将学生按班级分为实验组和对照组,实验组采用了以“设计布鲁姆认知教育目标、融合翻转课堂模式和问题导向教学”等为主线的混合教学模式,对照组依然采用传统教学模式,最后根据访谈、教学平台留言和统一的测验题等方式评价教学效果。结果表明混合教学模式的教学效果优于传统教学,且实验组所有学生都愿意继续接受这种新的教学模式。教学实践证明,学生在制定自身学习目标及建立相应的自我调节学习策略方面有明显的改进。

新型大黄酸衍生物4F抑制MCF-7细胞增殖并通过旁凋亡途径诱导细胞死亡（英文）

目的:探讨大黄酸及其衍生物4F对MCF-7细胞增殖能力、亚显微结构的影响及诱导细胞死亡的分子机制。方法:采用CCK-8法、克隆形成实验、流式细胞仪检测比较4F、大黄酸和顺铂对乳腺癌细胞MCF-7的抗肿瘤活性;采用透射电镜观察MCF-7细胞质空泡及线粒体;免疫印迹实验则用于测定旁凋亡、自噬和凋亡相关蛋p62、微管相关蛋白轻链3(LC3)、葡萄糖调节蛋白(Grp)78、cleaved caspase-9和caspase-7的表达水平。结果:4F比大黄酸具有更强的细胞毒性(P<0.05),但均对MCF-7细胞凋亡率无明显影响(P>0.05);4F处理的MCF-7细胞质中可观察到大量空泡及肿胀的线粒体;免疫印迹结果显示Grp78、p62及LC3表达水平增高(P<0.05),而凋亡相关蛋白cleaved caspase-9及caspase-7表达水平无显著改变(P>0.05)。结论:4F可能通过旁凋亡,一种非凋亡或自噬性死亡的方式,诱导MCF-7细胞死亡;4F有望成为克服凋亡耐药的候选药物。

神经内镜下脑室血肿清除术与脑室外引流术治疗脑室内出血的疗效分析

目的对比神经内镜辅助下血肿清除术与脑室外引流术治疗脑室内出血(IVH)的临床疗效。方法选择高密市人民医院神经外科自2019年1月至2022年2月收治的42例IVH患者,按照随机数字表法分为内镜组与穿刺组,每组21例。内镜组予以神经内镜下脑室血肿清除术治疗,穿刺组行侧脑室外引流术治疗,比较2组患者术后8 h颅脑CT的Graeb评分、尿激酶注射次数、置管时间、术后并发症(颅内感染、再出血、脑积水)发生率、术后3个月患者的神经功能恢复情况(GOS评分)。结果内镜组患者术后8 h的血肿清除情况优于穿刺组,Graeb评分低于穿刺组,差异有统计学意义(P<0.05)。内镜组患者尿激酶注射次数、置管时间均少于穿刺组,差异有统计学意义(P<0.05)。内镜组术后并发症的发生率(14.29%)低于穿刺组(38.10%),但差异无统计学意义(P>0.05)。内镜组术后3个月的预后良好率高于穿刺组,差异有统计学意义(P<0.05)。结论神经内镜治疗IVH安全可行,是一种潜在的有效手术方式,需要更多临床试验数据的验证。

温敏漆应用于高超声速燃烧辐射环境的方法

热防护系统设计需要高空间分辨率的热流密度场测 量 方法来获取热流密度峰值及其对应的空间位 置 然而, 燃烧产生的背景 辐射严重阻碍了现有热流密度场测 量 方法的应用. 为了解决该难题, 提出了一种适用于强辐射燃烧环境的热流密度场测 量 方法, 基本 思想是利用温敏漆测 量 燃烧室外壁面温度的变化历程结合三维瞬态热传导反问题的求解确定内壁面热流密度场分布. 文中详细介绍 了测量系统构成、 数据处理方法及温敏漆涂层厚度对测 量 结果的影响, 最后给出了数值和实验结果验证了该方法的可行性.

An FV-EE model to predict lean blowout limits for gas turbine combustors with different structures and sprays

The occurrence of Lean Blowout(LBO)is a disadvantage that endangers a stable operation of gas turbines.A determination of LBO limits is essential in the design of gas turbine combustors.A semiempirical model is one of the most widely used methods to predict LBO limits.Among the existing semiempirical models for predicting LBO limits,Lefebvre’s LBO model and the Flame Volume(FV)model are particularly suitable for gas turbine combustors.On the basis of Lefebvre’s and FV models,the concept of effective evaporation efficiency is introduced in this paper,and a Flame Volume-Evaporation Efficiency(FV-EE)model is derived and validated.LBO experiments are carried out in a model combustor with 23 different structures and 10 different sprays.The prediction uncertainty of the FV-EE model is less than±13%for all of these 33 structures and sprays,compared with±50%for the FV model and±60%for Lefebvre’s model.Furthermore,the prediction uncertainty of the FV-EE model is also less than±13%for other combustors from available literature.

Criteria for hypersonic airbreathing propulsion and its experimental verification

Hypersonic airbreathing propulsion is one of the top techniques for future aerospace flight, but there are still no practical engines after seventy years’ development. Two critical issues are identified to be the barriers for the ramjet-based engine that has been taken as the most potential concept of the hypersonic propulsion for decades. One issue is the upstream-traveling shock wave that develops from spontaneous waves resulting from continuous heat releases in combustors and can induce unsteady combustion that may lead to engine surging during scramjet engine operation.The other is the scramjet combustion mode that cannot satisfy thrust needs of hypersonic vehicles since its thermos-efficiency decreases as the flight Mach number increases. The two criteria are proposed for the ramjet-based hypersonic propulsion to identify combustion modes and avoid thermal choking. A standing oblique detonation ramjet(Sodramjet) engine concept is proposed based on the criteria by replacing diffusive combustion with an oblique detonation that is a unique pressure-gain phenomenon in nature. The Sodramjet engine model is developed with several flow control techniques, and tested successfully with the hypersonic flight-duplicated shock tunnel.The experimental data show that the Sodramjet engine model works steadily, and an oblique detonation can be made stationary in the engine combustor and is controllable. This research demonstrates the Sodramjet engine is a promising concept and can be operated stably with high thermal efficiency at hypersonic flow conditions.

A Plant Immune Receptor Degraded by Selective Autophagy

Plants recycle non-activated immune receptors to maintain a functional immune system.The Arabidopsis immune receptor kinase FLAGELLIN-SENSING 2 (FLS2)recognizes bacterial flagellin.However,the molecular mechanisms by which non-activated FLS2 and other non-activated plant PRRs are recycled remain not well understood.Here,we provide evidence showing thatArabidopsis orosomucoid (ORM)proteins,which have been known to be negative regulators of sphingoUpid biosynthesis,act as selective autophagy receptors to mediate the degradation of FLS2.Arabidopsis plants overexpressing ORM 1 or ORM2 have undetectable or greatly diminished FLS2 accumulation,nearly lack FLS2 signaling,and are more susceptible to the bacterial pathogen Pseudomonas syringae.On the other hand,ORM1/2 RNAi plants and orml or orrn2 mutants generated by the CRISPR/Cas9-mediated gene editing have increased FLS2 accumulation and enhanced FLS2 signaling,and are more resistant to P.syringae.ORM proteins interact with FLS2 and the autophagy-related protein ATG8.Interestingly,overexpression of ORM1 or ORM2 in autophagydefective mutants showed FLS2 abundance that is comparable to that in wild-type plants.Moreover, FLS2 levels were not decreased in Arabidopsis plants overexpressing ORM1/2 derivatives that do not interact with ATGS.Taken together,these results suggest that selective autophagy functions in maintaining the homeostasis of a plant immune receptor and that beyond sphingolipid metabolic regulation ORM proteins can also act as selective autophagy receptors.

A theoretical method for solving shock relations coupled with chemical equilibrium and its applications

In this study,a theoretical method is proposed to solve shock relations coupled with chemical equilibrium.Not only shock waves in dissociated flows but also detonation waves in combustive mixtures can be solved.The global iterative solving process is specially designed to mimic the physical and chemical process in reactive shock waves to ensure good stability and fast convergence in the proposed method.Within each global step,the single-variable equations of normal and oblique shock relations are derived and solved with the Newton iteration method to reduce the complexity of the problems,and the minimization of free energy method of NASA(National Aeronautics and Space Administration)is adopted to solve equilibrium compositions.It is demonstrated that the convergent process is stable and very close to the real chemical-kinetic process,and high accuracy is achieved in the solutions of normal and oblique reactive shock waves.Moreover,the proposed theoretical method has also been applied to many problems associated with reactive shocks,including the stability of oblique detonation wave,bow detonation over a sphere,and shock reflection in dissociated air.The great importance of using chemical equilibrium to theoretically predict the theoretical range of the wedge angle for a standing oblique detonation wave(the standing window of the oblique detonation wave),the stand-off distance of bow detonation wave and the transition criterion of shock reflection in dissociated air with high accuracy have been addressed.

Aerodynamic force and moment measurement of 10°half-angle cone in JF12 shock tunnel

An aerodynamic force and moment measurement was conducted in JF12 long-testduration detonation-driven shock tunnel of Institute of Mechanics,Chinese Academy of Sciences.The test duration of JF12 is 100–130 ms.The nominal Mach number is 7.0 and the exit diameter of the contoured nozzle is 2.5 m.The total enthalpy is 2.5 MJ/kg which duplicates the hypersonic flight conditions of Mach number 7.0 at 35 km altitude.The test model is the standard aerodynamic force model of 10° half-angle sharp cone.The length of the test model is 1500 mm and the weight is 57 kg.The aerodynamic forces were measured with a six-component strain balance.The angles of attack were set to be à5°,0°,5°,10° and 14°,respectively.The experimental results show that in the 100–130 ms test duration,the signals of strain balance have 3–4 complete vibration cycles.So,the aerodynamic forces and moments can be obtained directly by averaging the signals of balance without acceleration compensation.The force measurement error of repeatability of JF12 is less than 2%.The aerodynamic force coefficients of JF12 are in good agreement with those of conventional hypersonic wind tunnels.For this test model at Mach number 7.0 and total enthalpy of 2.5 MJ/kg,the real-gas effects on aerodynamic force characteristics are not very evident.

Noise reduction for temperature-sensitive paint measurement contaminated by strong background radiation in a high enthalpy hypersonic tunnel

The strong background radiation in high enthalpy hypersonic shock tunnels has posed severe challenges for measurement using luminescent coatings.We proposed a solution for reducing background radiation from time-resolved temperature-sensitive paint(TSP)measurement in a hypersonic flow with Ma=6.5 and T_(0)=3525 K.The TSP was applied on an inlet ramp model,and the images were taken by a high-speed camera at 2 kHz under a modulated excitation.The strong background radiation led to a low signal-to-noise ratio and significant errors for the first half of the 130-ms test duration.Accordingly,three noise reduction methods were developed and evaluated based on temporal reconstruction,spatial reconstruction and robust principal component analysis(RPCA),respectively.The RPCA method showed the best performance that successfully recovered high-quality TSP data for a majority of test duration(t≥40 ms).

RoTFL1c of Rosa multiflora has a dual-function in suppressing reproductive growth and promoting vegetative growth of Arabidopsis

Dear Editor, TFL1homologues play a key role in the flowering habit of roses.To analyze the function of the newly isolated TFL1 gene of Rosa multiflora(Chen et al.,2013),named RoTFLlc,we performed overexpression analyses in Arabidopsis thaliana.When compared with empty vector control and wild type Arabidopsis plants,RoTFLlc overexpressing transgenic plants exhibited strong phenotypes such as a clustered habit,an increased number of rosette leaves, late flowering or failure to flower.