剪切波弹性成像技术对低强度脉冲超声刺激足三里穴引起肌张力变化的评估

目的:应用剪切波弹性成像技术(SWE)评估低强度脉冲超声(LIPUS)刺激足三里穴位时肌张力的变化特点,初步探讨LIPUS刺激穴位的可行性,以期为LIPUS在外周神经调控研究中提供定量评估信息。方法:实验动物为16只雄性SD大鼠,随机分为胫骨前肌组和腓肠肌组各8只,应用LIPUS刺激大鼠足三里穴20 min,通过SWE连续监测胫骨前肌和腓肠肌的肌张力变化。酶联免疫吸附试验(ELISA)测定刺激前后血清5-羟色胺(5-HT)水平变化。结果:胫骨前肌在LIPUS刺激足三里穴后3 min的剪切波速度和杨氏模量值均较刺激前显著升高(均P<0.05);腓肠肌在刺激足三里穴后13、14 min的剪切波速度和杨氏模量值均较刺激前显著升高(均P<0.001)。血清5-HT水平较刺激前显著升高(P<0.05)。结论:SWE可为评估LIPUS刺激足三里穴位引起的肌张力变化提供客观依据,为LIPUS的经穴效应的研究提供更多信息。

超声评估糖尿病性胃轻瘫大鼠胃动力

目的观察超声评估糖尿病性胃轻瘫(DGP)大鼠胃动力的价值。方法将以普通饲料适应性饲养1周的26只SD大鼠随机分为模型组(n=18)和对照组(n=8),分别以高脂高糖饲料和普通饲料饲养1周。对模型组大鼠通过经腹腔注射1%链脲佐菌素(STZ)溶液联合不规律高脂高糖饲料法饲养建立DGP模型,对照组予以经腹腔注射等量柠檬酸缓冲溶液联合规律普通饲料法饲养。成功建模后检测2组大鼠血糖值;行超声检查,记录胃动力参数;以离体胃窦肌条实验和病理检查观察胃窦肌层最大收缩力和形态。结果模型组16只造模成功、2只死亡。模型组大鼠糖耐量水平显著高于对照组(P均<0.05);胃窦最小收缩面积大于,而胃窦收缩幅度、胃窦动力指数、实验餐后30及60 min胃排空率均小于对照组(P均<0.05);离体胃窦平滑肌肌条最大收缩力小于对照组(P<0.001)。光镜下观察,模型组大鼠胃窦组织可见明显DGP病理改变。结论超声可用于评估DGP大鼠胃动力。

Red fluorescent siloles with aggregation-enhanced emission characteristics

Aseries of new red fluorescent siloles consisting of a silole core and dimesitylboranyl substituent connected with a furan,thiophene,and selenophene bridges were synthesized and characterized.The optical properties,electronic structures,and electroluminescence (EL) performances were investigated.The emission wavelengths were red-shifted from the siloles with furan,to those with thiophene,and then selenophene.The thiophene,and selenophene-containing siloles,(MesB)_2DTTPS,and(MesB)_2DSTPS,showed the typical aggregation-enhanced emission (AEE) feature,while furan-containingone,(MesB)_2DFTPS,showed slight emission decrease as the aggregate formation.Theoretical calculations were carried out to explain the difference in the optical properties.Undoped OLEDs using these red siloles as light-emitting layers were fabricated.The device of (MesB)_2DTTPS exhibited the bestper formance.It radiated red ELemission at 589 nm,and afforded good maximum luminance,current,power,and external quantum efficiency of13300cdm^(-2),4.3cd A^(-1),2.9 lmW^(-1),and1.8%,respectively.

A transition prediction method for flow over airfoils based on high-order dynamic mode decomposition

This article presents a novel approach for predicting transition locations over airfoils,which are used to activate turbulence model in a Reynolds-averaged Navier-Stokes flow solver.This approach combines Dynamic Mode Decomposition(DMD)with e^Ncriterion.The core idea is to use a spatial DMD analysis to extract the modes of unstable perturbations from a steady flowfield and substitute the local Linear Stability Theory(LST)analysis to quantify the spatial growth of Tollmien–Schlichting(TS)waves.Transition is assumed to take place at the stream-wise location where the most amplified mode’s N-factor reaches a prescribed threshold and a turbulence model is activated thereafter.To improve robustness,the high-order version of DMD technique(known as HODMD)is employed.A theoretical derivation is conducted to interpret how a spatial highorder DMD analysis can extract the growth rate of the unsteady perturbations.The new method is validated by transition predictions of flows over a low-speed Natural-Laminar-Flow(NLF)airfoil NLF0416 at various angles of attack and a transonic NLF airfoil NPU-LSC-72613.The transition locations predicted by our HODMD/e^Nmethod agree well with experimental data and compare favorably to those obtained by some existing methods■.It is shown that the proposed method is able to predict transition locations for flows over different types of airfoils and offers the potential for application to 3D wings as well as more complex configurations.

A Silole-Based Efficient Electroluminescent Material with Good Electron-Transporting Potential

A new silole derivative, 2,5-bis（7-（dimesitylboranyl）-9,9-dimethylfluoren-2-yl）- 1 -methyl- 1,3,4-triphenylsilole （（MesBF）2MTPS）, is synthesized and characterized. （MesBF）2MTPS shows a good fluorescence efficiency of 15% in THF solution and a higher efficiency of 86% in solid film, presenting an aggregation-enhanced emission charac- teristic. It is thermally and morphologically stable, with high decomposition and glass-transition temperatures of 257 and 171 ℃, respectively. The LUMO energy level （-2.96 eV） of （MesBF）zMTPS is lower than that of TPBi, revealing its electron-transporting potential. Efficient organic light-emitting diodes （OLEDs） are fabricated using （MesBF）2MTPS as emitter, which radiates yellow light at 554 nm, and affords high maximum luminance, current efficiency, and external quantum efficiency of 48348 cd·m^-2, 12.3 cd·A^-1, and 4.1%, respectively.

3,4,5-Triphenyl-1,2,4-triazole-based multifunctional n-type AIEgen

The luminogens with aggregation-induced emission(AIEgens) characteristics have been widely applied in diverse areas. However,the n-type AIEgens are to be further developed. In this paper, we designed and synthesized an n-type multifunctional AIEgen of tetraphenylethene-substituted 3,4,5-triphenyl-4H-1,2,4-triazole(BTPE-TAZ). This AIEgen can serve as both light-emitting and electron-transporting layers in organic light-emitting devices. Moreover, it also exhibits the interesting optical waveguide and reversible mechanochromic luminescence properties, which are of great potential for practical applications.

Application of surrogate models to stability analysis and transition prediction in hypersonic flows

To increase the efficiency and robustness of stability-based transition prediction in flow simulations, simplified methods are introduced to substitute direct stability analyses for rapid disturbance growth prediction. For low-speed boundary layers, these methods are mainly established based on self-similar assumptions, which are not applicable to non-similar boundary layers in hypersonic flows. The objective of this article is to investigate the application of surrogate models to stability analysis of non-similar flows over blunt cones, focused on parameterization of boundary-layer (BL) profiles. Firstly, correlations between BL edge and profile parameters are analyzed, along with self-similar flow parameters and discrete points on BL profiles, which present four groups of BL characteristic parameters. Secondly, using these parameters as inputs, surrogate models are built for disturbance growth prediction over an MF-1 blunt cone. Results show that, surrogate models using four BL edge parameters and a BL shape factor {Ue, Te, ρe, ηe, H12} for stability analysis can achieve comparable accuracy with those using 16 discrete BL profile parameters, which are more precise than those using merely self-similar parameters or BL edge parameters. Thirdly, the established surrogate models are validated by stability analysis and transition prediction over the MF-1 blunt cone in flight experiments at the instants of t = 17 s ~ 22 s. Compared with direct linear stability analyses, the mean relative error of predicted disturbance growth rates by surrogate models is 8.0% and the maximum relative error of N factor envelopes is 6.6%, which indicates feasible applications of surrogate models to stability analysis and transition prediction of non-similar boundary layers in hypersonic flows.

Blue fluorophores comprised of tetraphenylethene and imidazole： aggregation-induced emission and electroluminescence

By melting tetraphenylethene （TPE） and 1,2,4,5-tetraphenyl-lH-imidazole （TPI） units together through different linking positions, three new fluorophores are synthesized, and their optical, electronic and electro- luminescence （EL） properties are fully studied. Owing to the presence of TPE unit（s）, these fluorophores are weak emitters in solutions, but are induced to emit strongly in the aggregated state, presenting typical aggregation-induced emission characteristics. The experimental and computational results reveal that different connection patterns between TPE and TPI could impact the molecular conjugation greatly, leading to varied emission wavelength, fluorescence quantum yield and EL performance in organic light emitting diodes （OLEDs）. The fluorophore built by attaching TPE unit to the 1-position of imidazole ring shows bluest fluorescence, and its EL device emits at deep blue region （445 nm; CIE= （0.16, 0.15））. And the device based on the fluorophore by linking TPE to the 2- position of imidazole ring shows EL at 467 nm （CIE= （0.17, 0.22）） with good efficiencies of 3.17 cd.A ^-1, and 1.77%.