Molecular characterization of human reticulon 3 as a potential marker during the differentiation of human neuroblastoma SH-SY5Y cells

Neuroendocrine-specific protein (NSP) -reticulons are endoplasmic reticulum-associated protein complexes, which are localized in the endoplasmic reticulum (ER) and identified as markers for neuroendocrine differentiation. In the present study, human reticulon 3 gene (hRTN3) was cloned and its expression pattern in a variety of tissues was investigated. Truncated hRTN3s corresponding to the C-terminal (hRTN3-C) domain were expressed and purified. hRTN3 mRNA was down-regulated during the differentiation of human neuroblastoma cell line SH-SY5Y induced by all-trans-retinoic acid (RA), which suggests that, like other members of the reticulon family, hRTN3 is a potential marker for neuroendocrine differentiation.     

Novel sintering behavior of polystyrene nano-latex particles in filming process

Filming process of polystyrene nano-latex (NPS) particles was studied by a combination of various methods. For a constant annealing time of 1 h, the AFM images showed that the deformation and sintering temperatures for NPS particles were ca. 90℃ and 100℃ respectively. In spin-lattice relaxation measurements of solid state NMR, it is found that T_1L, T_1S and I_1L/I₀ increased significantly after annealing at 90℃ and above. DSC results showed that there was an exothermic peak near T_g after annealing for 1 h at the selected temperatures below 95℃; otherwise, the exothermic peak disappeared after annealing at 100℃ or above. The apparent density of NPS increased suddenly in the temperature range. The results implied that the macromolecules in NPS particles are in a confined state with higher conformational energy and less cohensional interactions which are the drive force for the sintering at a lower temperature compared with the multichain PS particles and the bulk polymer.     

Geometrical enhancement of low-field magnetoresistance in silicon

Inhomogeneity-induced magnetoresistance (IMR) reported in some non-magnetic semiconductors, particularly silicon, has generated considerable interest owing to the large magnitude of the effect and its linear field dependence (albeit at high magnetic fields). Various theories implicate spatial variation of the carrier mobility as being responsible for IMR. Here we show that IMR in lightly doped silicon can be significantly enhanced through hole injection, and then tuned by an applied current to arise at low magnetic fields. In our devices, the 'inhomogeneity' is provided by the p-n boundary formed between regions where conduction is dominated by the minority and majority charge carriers (holes and electrons) respectively; application of a magnetic field distorts the current in the boundary region, resulting in large magnetoresistance. Because this is an intrinsically spatial effect, the geometry of the device can be used to enhance IMR further: we designed an IMR device whose room-temperature field sensitivity at low fields was greatly improved, with magnetoresistance reaching 10% at 0.07?T and 100% at 0.2?T, approaching the performance of commercial giant-magnetoresistance devices. The combination of high sensitivity to low magnetic fields and large high-field response should make this device concept attractive to the magnetic-field sensing industry. Moreover, because our device is based on a conventional silicon platform, it should be possible to integrate it with existing silicon devices and so aid the development of silicon-based magnetoelectronics.     

α-蒎烯促进海洋真菌Aspergillus sp.产真菌毒素青霉酸的研究

采自南海软珊瑚Sarcophyton tortuosum的内生真菌Aspergillus sp.在由葡萄糖10g/L,蛋白胨5 g/L,酵母膏2 g/L,100%海水,pH为7.5的培养基(GPY)中能够产生真菌毒素青霉酸,产量为5.5 mg/L.在GPY培养基中添加200 mg/L的单萜α-蒎烯,能改变代谢产物的组成和含量,并显著促进该真菌产生青霉酸,产量可提高至29.15 mg/L.结果表明α-蒎烯在该菌的作用下主要得到系列氧化产物,并进一步发生氧化降解.单萜α-蒎烯可以作为一个有效的诱导子,引起微生物的氧化应激反应,改变膜上酶系的活性,使代谢活动得到调控,改变代谢产物组成或产量,在微生物发酵工业上有潜在应用.     

二元有向向量的Pade－逼近

本文借助于一组线性无关的方向向量构造了二元有向向量的Ｐａｄｅ－逼近，给出的计算例子说明了构造的有效性．     

轴承磨削表面谐波仿真与控制系统

作者研制的轴承磨削表面谐波仿真与控制系统具有数据生成、参数优化、仿真预测与诊断误差等功能。系统操作采用控制屏幕编辑、下拉式和弹出式菜单等技术，仿真结果均以图形或汉字形式输出。本系统的研制，为实施轴承磨削表面谐波的工艺过程控制提供了一种有效手段。     

Wnt信号通路与干细胞定向分化

Wnt信号通路在胚胎发育过程中参与背腹轴的形成、细胞极性的建立以及决定细胞命运.利用干细胞定向分化模型可在体外培养条件下探索Wnt信号通路在哺乳动物早期胚胎发育过程中的分子机理,了解其信号网络对干细胞定向分化中各个事件的调控机制.本文通过综合近期Wnt信号通路的研究,阐述经典Wnt信号通路(Canonical Wnt signaling pathway)在干细胞定向分化中的作用.     

基于随机Petri网的流通加工系统建模研究

流通加工系统是一个动态离散系统,影响该系统的因素多具有并发性、异步性及随机性的特点,所以定性和定量分析流通加工系统较为复杂.以三华农副产品加工基地农副产品的一次流通加工为研究背景,利用随机Petri网构建了反映该企业流通加工系统的实际组成及运行状态的随机Petri网模型,并对该模型进行了定性分析和定量分析.其中,定性分析是根据连续时间的随机Petri网同构于连续时间马尔科夫链的特点对模型的活性、可达性、有界性等进行了分析;定量分析是利用带有模糊参数的随机Petri网求解出库所繁忙的概率、系统变迁的利用率、系统平均延时时间及流入系统的标记流速.根据所得数据分析可知:应进一步优化加工环节,流入系统的标记流速还应加快.     

基于联想记忆的Hopfield神经网络的设计与实现

介绍了反馈型神经网络Hopfield网络的定义、原理、模型和基本学习规则,并构造了一个用于联想记忆的Hopfield神经网络模型.对实验结果进行分析、比较,实验结果表明:Hopfield神经网络用于数字识别是可行、有效的;该方法较传统神经网络能提高网络的记忆能力和数字识别的正确率;该方法有别于以往的BP神经网络的模式识别,结合一些优化算法,如遗传算法,能对Hopfield神经网络的联想记忆稳态进行优化,增强神经网络的联想记忆能力.     

电气化铁路谐波治理工程设计与研究

文章根据某地区电气化铁路对电网造成的谐波等电能质量问题,提出了在电气化铁路牵引变电站安装滤波器组来解决谐波问题的方案.该方案采用单调谐滤波器作为牵引变电站的滤波装置,起到滤除电气化铁路引起的谐波的作用,并详细介绍了治理装置的系统方案设计过程.