Naphthalimide-rhodamine based fluorescent probe for ratiometric sensing of cellular pH

The pH values of lysosomes in cancer cells is slightly lower than that in normal cells, which can be used to distinguish cancer cells from normal cells. According to this, a naphthalimide-rhodamine based fluorescent probe(hereafter referred to as RBN) with a pK_a of 4.20 was designed and synthesized for ratiometric sensing of cellular pH via fluorescence resonance energy transfer(FRET), which can respond to different pH precisely through ratiometric fluorescence intensity(Ⅰ_(577)/Ⅰ_(540)). RBN can be employed to distinguish cancer cells from normal cells on the basis of different fluorescent response, in particular, RBN showed excellent water solubility and low cell toxicity, all these are quite significant for potential application in cancer diagnose and therapy.     

Hydrothermal synthesis of peony-like CuO micro/nanostructures for high-performance lithium-ion battery anodes

The peony-like CuO micro/nanostructures were fabricated by a facile hydrothermal approach. The peonylike CuO micro/nanostructures about 3-5 μm in diameter were assembled by CuO nanoplates. These CuO nanoplates, as the building block, were self-assembled into multilayer structures under the action of ethidene diamine, and then grew into uniform peony-like CuO architecture. The novel peony-like CuO micro/nanostructures exhibit a high cycling stability and improved rate capability. The peony-like CuO micro/nanostructures electrodes show a high reversible capacity of 456 mAh/g after 200 cycles, much higher than that of the commercial CuO nanocrystals at a current 0.1 C. The excellent electrochemical performance of peony-like CuO micro/nanostructures might be ascribed to the unique assembly structure, which not only provide large electrode/electrolyte contact area to accelerate the lithiation reaction, but also the interval between the multilayer structures of CuO nanoplates electrode could provide enough interior space to accommodate the volume change during Li~+ insertion and de-insertion process.     

The Effect of Intermolecular Hydrogen Bonding on the Polyaniline Water Complex

The polyaniline water hydrogen-bonded complex was studied by first-principles calculation. The density functional theory method was used to calculate the structure characters, natural bond orbital charge distribution, infrared spectra and the frontier molecular orbital. Results showed that the H–O···H–N and C–N···H–O type intermolecular hydrogen bonds were formed. The bonds involved in the intermolecular H-bond were all influenced by the hydrogen bonding interaction. During the hydrogen bond formation, the polymer chains in the complexes were all charged, which can be an important factor contributing to the increase of electrical conductivity. The N1–H vibration was strongly influenced, and the locations as well as the intensities of N1–H absorption bands were all changed in the complexes. In the orbital transition of HOMO to LUMO, the electron density transferred from benzenoid ring to quinoid ring.     

Solubility of Nifedipine and Lacidipine in Supercritical CO<Subscript>2</Subscript>: Measurement and Correlation

Solubilities of two calcium channel blockers, nifedipine and lacidipine, were measured in supercritical carbon dioxide at T = (313, 323, and 333) K over the pressure range (12.0–36.0) MPa using a dynamic-analytical apparatus. The solubility values obtained are in the range of (0.18–7.05) × 10^?5 mol·mol^?1. The solubilities of the two solids show similar trends with a crossover region of the respective isotherms in the range 18.0–21.0 MPa. The experimental solubility data were correlated with several different models. The semi-empirical density-based models provided satisfactory correlation results with AARD values lower than 10%. According to the results of the Méndez-Santiago and Teja models, the measured solid solubility data are quite consistent at all experimental conditions, which indicates the reliability of the data. The compressed gas model of the Peng–Robinson equation of state, combined with the two parameter van der Waals mixing rule (PR-EoS-VDW2) model, gives better correlation results than the PR-EoS-VDW1 model. The expanded liquid model based on Scatchard–Hildebrand regular solution theory can be used for solubility prediction, but the correlation results for nifedipine and lacidipine by the model are inferior to the compressed gas models in this work.     

聚吡咯/多壁碳纳米管及其聚氨酯导电复合材料的制备和性能

以羧基化多壁碳纳米管(MWCNTs)做模版剂,采用化学氧化法将吡咯(Py)在羧基化MWCNTs表面聚合制备PPy/MWCNTs导电材料,将其添加到溶剂型聚氨酯(PU)溶液中制备了PPy/MWCNTs/PU导电复合材料,研究了Py用量对PPy/MWCNTs及其PU复合材料性能的影响.研究表明,随Py用量的增加,PPy/MWCNTs的长度不变,管径增大,sp~2和sp~3杂化C含量先提高后减少,N的掺杂梯度降低,PPy/MWCNTs的导电率高于羧基化MWCNTs和PPy.当Py用量为羧基化MWCNTs的20%时,其导电率最大.PPy/MWCNTs中N元素的掺杂程度及其管径变化是引起PPy/MWCNTs/PU复合材料的性能不同的主要原因.增加Py用量,MWCNTs中亲水的羧基因对PPy掺杂而消耗,相同导电材料用量时纳米导电粒子数目相对减少,PPy/MWCNTs/PU复合材料的耐水性能提高,定向应力、储能模量和玻璃化温度降低,导电率先增加后减小.当Py用量为羧基化MWCNTs的15%时,导电率最大.     

橡胶在动态载荷下的能量损耗分析

以交联密度不同的同类轮胎胎面胶A1和A2为研究对象,通过动态拉伸实验得到储能模量及损耗模量随频率变化的曲线.建立了黏弹性广义Maxwell模型来定量分析不同温度的橡胶在不同频率的动态载荷下的能量损耗.采用非线性规划的方法分别在低频(10~25 Hz)及高频(25~60 Hz)下拟合模量-频率曲线,得到黏弹性广义Maxwell模型的参数值.采用有限元软件Abaqus模拟胎面胶动态拉伸过程并计算胎面胶的损耗角正切,得到不同温度下胎面胶的损耗角正切随激振频率的变化规律,通过和实验结果的比较证明文中所述黏弹性广义Maxwell模型及其参数获取方法可准确应用于胎面胶的动态拉伸性能分析.预测了在不同温度及频率下每一循环载荷周期中胎面胶的应力-应变迟滞回线以及单位体积胶料的能量损耗,阐释了不同温度下的胎面胶的能量损耗随频率的变化规律,同时结合2种胎面胶的交联密度测试数据分析了胶料的构效关系.     

基于甲基三苯乙炔基硅烷的新型聚三唑树脂的制备与性能

首先采用格氏试剂法合成了甲基三苯乙炔基硅烷(MTPES),通过傅里叶变换红外光谱(FT-IR)、核磁共振氢谱(1 H-NMR)对其结构进行了表征。然后以MTPES和4,4’-二叠氮甲基联苯(BAMBP)为原料制备了新型聚三唑树脂(MPTA)。利用FT-IR和差示扫描量热(DSC)研究了MPTA树脂的固化行为,通过动态力学热分析(DMA)和热重分析(TG)研究了炔基与叠氮基配比对树脂热性能的影响,并通过测试凝胶时间随贮存时间的变化研究了树脂及其四氢呋喃(THF)溶液的贮存稳定性。结果表明,固化后的树脂玻璃化转变温度(Tg)达到236℃,在氮气中的5%热失重温度(T_(d5))在320℃左右。MPTA树脂在35℃和25℃下分别贮存7d和20d后,100℃下树脂的凝胶时间分别为40min和25min,MPTA树脂的THF溶液在同样条件下贮存28d后,凝胶时间分别为54min和61min,具有比现有聚三唑树脂更好的贮存稳定性。单向T700碳纤维-MPTA复合材料常温下的弯曲强度为1 660 MPa,弯曲模量为129 GPa,150℃下的弯曲强度保留率为70%。     

含苯并咪唑和异噁唑结构席夫碱的合成及其抑菌活性

根据活性亚结构拼接原理,以取代苯甲醛、盐酸羟胺、N-氯代丁二酰亚胺和2-苯并咪唑基乙腈等为原料,经肟化、氯代、环化及缩合反应,合成了一系列新型的含苯并咪唑和异噁唑结构的席夫碱化合物(5a~5h),收率60%~75%,其结构经~1H NMR,~(13)C NMR,IR和HR-MS表征。采用菌丝生长速率法测试了化合物对番茄灰霉菌和生菜菌核菌的抑菌活性。结果表明:在用药量为100μg·m ~(-1)时,苯环上含有氟原子或甲氧基的席夫碱(5c,5d和5e)对生菜菌核菌显示出较好的活性,抑制率为71.3%~76.1%。     

A novel method to prepare microcellular poly(vinyl alcohol) foam based on thermal processing and supercritical fluid

Combining the thermal processing and supercritical fluid technology develops a novel preparation method of microcellular poly(vinyl alcohol) (PVA). Water, as the plasticizer in system, can form the hydrogen bonding with pendant hydroxyl of PVA and weaken its strong intermolecular and intramolecular forces to realize the thermal processing. Supercritical carbon dioxide (sc‐CO₂) can easily dissolve into water‐plasticized PVA (WPVA) because of the destruction of crystal region caused by water, and the enhanced sc‐CO₂ solubility can greatly improve the foamability of WPVA. The porous structure generates through the saturation of sc‐CO₂ in WPVA sample and followed by pressure drop‐induced phase separation. The foaming behavior of WPVA was studied as a function of saturation pressure, foaming temperature, and saturation time. The cell density, cell size, and distribution of the obtained foam can be controlled by tuning processing conditions. The results revealed that the cell size decreased, and its distribution narrowed with saturation pressure increasing, or decrease of foaming temperature. But excessively increasing the saturation time generated a negative effect on the foaming behavior owing to the deteriorated plasticization effect resulted from the loss of water. Copyright © 2016 John Wiley & Sons, Ltd.     

Microporous activated carbons prepared from palm shell by thermal activation and their application to sulfur dioxide adsorption

Textural characterization of activated carbons prepared from palm shell by thermal activation with carbon dioxide (CO(2)) gas is reported in this paper. Palm shell (endocarp) is an abundant agricultural solid waste from palm-oil processing mills in many tropical countries such as Malaysia, Indonesia, and Thailand. The effects of activation temperature on the textural properties of the palm-shell activated carbons, namely specific surface area (BET method), porosity, and microporosity, were investigated. The activated carbons prepared from palm shell possessed well-developed porosity, predominantly microporosity, leading to potential applications in gas-phase adsorption for air pollution control. Static and dynamic adsorption tests for sulfur dioxide (SO(2)), a common gaseous pollutant, were carried out in a thermogravimetric analyzer and a packed column configuration respectively. The effects of adsorption temperature, adsorbate inlet concentration, and adsorbate superficial velocity on the adsorptive performance of the prepared activated carbons were studied. The palm-shell activated carbon was found to have substantial capability for the adsorption of SO(2), comparable to those of some commercial products and an adsorbent derived from another biomass.