Spontaneous Directional Self-Cleaning on the Feathers of the Aquatic Bird Anser cygnoides domesticus Induced by a Transient Superhydrophilicity

In nature, the feathers of the goose Anser cygnoides domesticus stay superhydrophobic over a long term, thought as the main reason for keeping the surface clean. However, contaminants, especially those that are oleophilic or trapped within textures, cannot be removed off the superhydrophobic feathers spontaneously. Here, a different self-cleaning strategy based on superhydrophilic feathers is revealed that is imparted by self-coating of the amphiphilic saliva, which enables removing away low-surface-tension and/or small-size contaminants by forming directional water sheeting depending on their unique anisotropic microstructures. Particularly, the surface superhydrophilicity is switchable to superhydrophobicity upon exposure to air for maintaining a clean surface for a long time, which is further enhanced by coating with self-secreted preening oil. By alternate switching between a transient superhydrophilicity and a long-term stable superhydrophobicity, the goose feathers exhibit an integrated smart self-cleaning strategy, which is also shared by other aquatic birds. An attractive point is the re-entrant structure of the feathers, which facilitates not only liquid spreading on superhydrophilic feathers, but also long-term stability of the cleaned surface by shedding water droplets off the superhydrophobicity feathers. Thus, artificial self-cleaning microtextures are developed. The result renews the common knowledge on the self-cleaning of aquatic bird feathers, offering inspiration for developing bioinspired self-cleaning microtextures and coatings.     

响应面法优化α-淀粉酶的酶反应体系

目的:采用单因素实验及响应面法优化α-淀粉酶的反应体系。方法:以淀粉为底物对象，以可溶性淀粉浓度、α-淀粉酶浓度、反应时间为考察因素，在单因素实验基础上，运用Box-behnken实验设计方法研究各因素及其交互作用对α-淀粉酶作用底物时的反应速度的影响。结果:建立α-淀粉酶酶反应体系的最佳反应条件为12.0 mg/mL可溶性淀粉、1.50 U/mL α-淀粉酶、10.0 min反应时间，在此条件下，α-淀粉酶表现出的反应速度达到（19.53±1.74） mmol/（L·min），接近模型中的预测数值18.75 mmol/（L·min）。结论:此优化α-淀粉酶酶反应体系的方法可行，能够使α-淀粉酶在反应过程中发挥的酶活最大化，为日后在此体系下进行糖苷酶抑制剂的研究奠定了基础，具有一定的指导意义。     

Pequi Oil,a MUFA/Carotenoid-Rich Oil,Exhibited Protective Effects against DSS-Induced Ulcerative Colitis in Mice

Inflammatory bowel diseases (IBD) affect the gastrointestinal tract, and the imbalance of intestinal immune homeostasis can trigger them. Pequi oil (PO), a monounsaturated (MUFA) and carotenoid-rich food with nutraceutical potential, could help reshape the intestinal immune response, ameliorating IBD outcomes. This study investigates the effects of a 28 days intake of PO on elements of the intestinal immune response of mice with DSS-induced ulcerative colitis (disease activity index, colonic damage, inflammatory cells and markers). PO reduces body weight, colonic crypt and goblet cell losses and ameliorates diarrhea. In the colon, it increases γδT cells and secretory-IgA and decreases CD8+T cells. In lymphoid organs, it reduces CD8+T cells. Moreover, it also reduces the IL-17 and CRP in plasma. PO oil promotes a less cytotoxic response that may protect mice from immunological injuries caused by an IBD in the intestinal mucosa, improving the disease prognosis. Practical applications: This study demonstrates that the intake of pequi oil contributes to the regulation of immune response and improves clinical and histological signs of DSS-induced ulcerative colitis in mice. Its effects in cytotoxic cell reduction and other inflammatory markers and stimulation of regulatory cells, and preservation of mucus-producing cells, provide news insights about the importance of the regular intake of this food to better prognosis of ulcerative colitis acute episodes. In addition, these findings encourage further studies with foods with a protective potential for the intestinal mucosa.     

隧道洞口上方危岩崩塌块石运动规律及其对隧道的危害

为揭示危岩崩塌块石的运动规律及其对下方隧道洞口的危害,以都香高速昭通段乐红隧道洞口高陡边坡危岩区崩塌体为研究对象,运用理论计算与Rockfall数值计算2种形式对危岩区崩塌体失稳后块石的运动特征进行预测,运用Abaqus有限元软件模拟不同初速度、不同冲击落点下块石冲击隧道结构的动力响应,揭示不同因素对块石冲击隧道结构的影响程度.结果 显示:理论计算与Rockfall数值计算结果吻合,崩塌块石经坠落、碰撞、滚动最终会与隧道引洞段上表面发生碰撞;与冲击落点相比,块石初速度对隧道结构的动力响应特性影响更大;块石冲击落点位于隧道圆拱圆心正上方位置时对隧道结构的损伤最大;不同冲击落点对碰撞回弹后块石的速度影响不大.     

Effects of nitric oxide on the alleviation of postharvest disease induced by Penicillium italicum in navel orange fruits

The present study evaluated the effects of 15 μL L^-1 nitric oxide (NO) on the fruit defence response of ‘Newhall’ navel orange. The decay rate of NO-treated navel orange fruits was significantly lower than that of control fruits during storage at 20 °C storage (P < 0.05). Treatment with NO suppressed the increase in disease incidence and lesion area in orange fruits inoculated with Penicillium italicum (P. italicum); significantly increased the activities of phenolic metabolism-associated enzymes and pathogenesis-related (PR) proteins, including polyphenoloxidase (PPO), phenylalanine ammonia-lyase (PAL), β-1,3-glucanase (GLU) and chitinase (CHT); and enhanced the activities of key enzymes, including 4-coumarate: CoA ligase (4CL), cinnamate-4-hydroxylase (C4H) and chalcone isomerase (CHI) in the phenylpropanoid pathway. The contents of total phenolics, flavonoids and lignin were also higher in NO-treated fruits than in control fruits. The findings suggest that exogenous NO could induce disease resistance against P. italicum in navel orange fruits.     

基于AD598的LVDT电路稳定性分析

介绍了LVDT传感器和AD598芯片的工作原理，指出了LVDT传感器电路在使用AD598芯片时常见的稳定性问题，通过波特图和公式计算的方法分析了工程应用中出现稳定性问题的原因。运用网络分析仪测试了使用AD598的LVDT传感器电路在带有不同容性负载时的幅频响应特性，实际测量了航空发动机控制系统中LVDT信号传输线缆的寄生电容分布情况，量化分析了寄生电容对传感器工作稳定性的影响。同时针对该类稳定性问题提出了一种易于实施的解决措施，通过试验验证了措施的有效性。LVDT传感器在航空发动机控制系统中应用广泛且十分重要，其信号稳定性的提升对于航空发动机的整体性能有着非常重要的意义。     

阻尼器响应放大技术研究与应用进展

目前，阻尼器在工程结构减隔震控制领域的应用已极为广泛，但存在中小地震作用下阻尼器的位移和速度等较小时，阻尼器难以充分发挥耗能能力的问题。因此近年来阻尼器响应放大技术得到了国内外学者的广泛重视，并利用连杆机构、齿轮机构、杠杆机构、跨层支撑等提出了多种阻尼器响应放大装置。全面综述国内外阻尼器响应放大技术的研究和应用进展，包括装置构造和作用机理等。同时，分析现有阻尼器响应放大技术在遭遇极罕遇地震作用时阻尼器更容易失效等方面的不足，指出响应放大技术的研究和发展方向，以期为阻尼器响应放大技术的发展和极罕遇地震作用下确保工程结构的安全提供有效思路。