Biopolymers phase separation monitored by a plasmonic sensor

We report here a real-time study of interactions induced phase separation between β-lactoglobulin (BLG) and Acacia gum (AG) by analyzing the localized surface plasmon resonance of silver nanoparticles. We showed that the binding of BLG to AG is accompanied by refractive index changes, in relation with optical properties and structural changes of the complexes formed.     

Al2O3/TiC基陶瓷刀具材料的高温摩擦磨损性能研究

采用UMT-2球-盘式高温摩擦磨损试验机,考察了A l2O3/TiC基陶瓷刀具材料在200℃至600℃范围内的高温摩擦磨损性能,并分别使用大景深显微镜,白光干涉仪和扫描电镜观察试验后磨痕的轮廓和微观形貌.结果表明：A l2O3/TiC陶瓷刀具的摩擦系数随环境温度的升高先升高,在600℃时开始降低,摩擦系数的数值在0.1~0.4之间;磨损量随着摩擦滑动速度的升高而降低,随着摩擦环境温度的升高而升高,磨损量的数值在4×10-7~9×10-7mm3/（N.m）之间;随着摩擦温度的升高,磨痕轮廓两侧具有明显的材料转移现象,A l2O3/TiC陶瓷材料主要磨损机理是裂纹的产生与材料的脱落.     

Colorimetric quantification of mRNA expression in rare tumour cells amplified by multiple ligation-dependent probe amplification

An enzyme-linked oligonucleotide assay (ELONA) for quantification of mRNA expression of five genes involved in breast cancer, extracted from isolated rare tumour cells and amplified by multiplex ligation-dependent probe amplification (MLPA) is presented. In MLPA, a multiplex oligonucleotide ligation assay is combined with a PCR reaction in which all ligation products are amplified by use of a single primer pair. Biotinylated probes complementary to each of the target sequences were immobilised on the surface of a streptavidin-coated microtitre plate and exposed to single-stranded MLPA products. A universal reporting probe sequence modified with horseradish peroxidase (URP–HRP) and complementary to a universal primer used during the MLPA step was further added to the surface-bound duplex as a reporter probe. Simultaneous addition of anchoring probe and target, followed by addition of reporter probe, rather than sequential addition, was achieved with no significant effect on sensitivity and limits of detection, but considerably reduced the required assay time. Detection limits as low as 20 pmol L⁻¹, with an overall assay time of 95 min could be achieved with negligible cross-reactivity between probes and non-specific targets present in the MLPA-PCR product. The same MLPA-PCR product was analysed using capillary electrophoresis, the technique typically used for analysis of MLPA products, and good correlation was observed. The assay presented is easy to carry out, relatively inexpensive, rapid, does not require sophisticated instrumentation, and enables quantitative analysis, making it very promising for the analysis of MLPA products.     

活性碳/CoFe_2O_4复合物的制备及其对亚甲基蓝的吸附性能

通过低温回流法制备了具有磁分离响应的活性碳(AC)与CoFe2O4的复合物AC/CoFe2O4(MAC)。采用批式吸附实验法对MAC吸附溶液中偶氮染料亚甲基蓝(MB)的吸附动力学过程及吸附平衡进行了研究,考察了溶液初始pH值对MAC吸附MB的影响。结果表明,MAC吸附MB的过程很快,20min几乎达到平衡。MAC吸附MB过程可以用准二级动力学方程描述。等温吸附过程服从Langmuir方程,MAC对MB的饱和吸附容量为120.48mg/g。在较低pH值时,MB吸附量较小。随着pH值的升高,MAC对MB的吸附量增大。     

HPLC-MS/MS同时测定水产品中喹烯酮、喹乙醇和5种大环内酯类抗生素残留

建立了水产品中喹烯酮、喹乙醇和5种大环内酯类抗生素同时测定的高效液相色谱串联质谱法。向样品中加入无水硫酸钠,以乙酸乙酯-乙腈的混合溶液为提取剂,用正己烷净化。以乙腈-10 mmol/L甲酸铵溶液为流动相,流速为0.3 mL/min,以Hypersil GOLD为色谱分离柱,用配有电喷雾离子源的三重四极杆质谱进行定性定量分析。在1～1000 ng/mL范围内,7种药物呈良好线性关系。在鲫鱼、南美白对虾和甲鱼空白肌肉中添加水平为2～10μg/kg时,该方法的回收率为67.52%～108.89%,相对标准偏差为4.2%～14%,方法检测限为1μg/kg,定量限为2μg/kg。方法适用于同时测定水产品中喹烯酮、喹乙醇和5种大环内酯类药物的残留量。     

AlCl歧化反应分解法制备金属铝过程中[AlCl]_n的形成机理

利用密度泛函理论(DFT)中的广义梯度近似(GGA)法,对氧化铝真空还原氯化歧化法制备金属铝的过程中[AlCl]n(n=1-10)团簇的稳定结构、能量和团簇形成过程的过渡态及其振动频率进行了理论研究,预测了其基态结构及成长趋势.结果表明:[AlCl]n(n=1-10)团簇可能存在的结构都是以[Al]n骨架外接n个Cl原子成型,且具有较好的几何对称性;从过渡态计算得到的活化能来看,正过程的活化能总是比逆过程的活化能要小,即[AlCl]n(n=1-10)团簇具有较好的成长趋势.以上研究结果有助于进一步了解用碳热还原氯化歧化法制备金属铝过程中液态金属铝的生成.     

高固含量聚合物乳液流变性研究进展

近二十多年来,如何提高乳胶产品固含量一直是乳液制备工作所追求的重要目标之一。相对于传统乳液而言,高固含量具有更大的分散相体积分数,甚至达到70%(wt)以上。因此,高分散相体积分数状态下的流变性能一直成为高固含量乳液制备过程中的瓶颈。粒子尺寸及其分布在粘度控制过程中起着至关重要的作用。本文从单分散体系、多元分散体系和宽粒径分布体系三个方面,详细评述了近几年高固含量乳液流变研究领域的数学建模和实验研究。并对高固含量乳液流变性能研究的发展进行了展望。     

Emerging Hubs in Plant Light and Temperature Signaling

Due to their nature as sessile organisms, plants must accurately sense their surroundings and then translate this information into efficient acclimation responses to maximize development. Light and temperature are two major stimuli that provide immediate cues regarding energy availability, daylength, proximity of other species and seasonal changes. Both cues are sensed by complex systems and the integration of these signals is of very high value to properly respond to environmental changes without being disguised by random changes. For instance a cold day has a different significance if it occurs during the illuminated phase of the day or during the night, or when days are shortening during the fall instead of a long‐day in spring. Here, we summarize recent advances in the nature of signaling components that operate as connectors of light and temperature signaling, with emphasis on the emerging hubs. Despite the nature of the thermosensors is still in its infancy compared to an important body of knowledge about plant sensory photoreceptors, the interaction of both types of signaling will not only bring clues of how plants integrate environmental information, but also will help in leading research in the nature of the thermosensors themselves.