Electrophoretic separation of neurotransmitters on a polystyrene nano-sphere∕polystyrene sulphonate coated poly(dimethylsiloxane) microchannel

In this paper, a poly(dimethylsiloxane) microchip with amperometric detector was developed for the electrophoretic separation and determination of neurotransmitters. For increasing the separation efficiency, the microchannel is modified by polystyrene sulphonate∕polystyrene nano-sphere self-assembly coating. A stable electro-osmotic flow (EOF) and higher separation efficiency are obtained in proposed modified microchannel. Under optimized conditions, dopamine, epinephrine, catechol, and serotonin are acceptably baseline separated in this 3.5 cm length separation channel with the theoretical plate number from 4.6?×?10(4) to 2.1?×?10(5) per meter and resolution from 1.29 to 12.5. The practicability of proposed microchip is validated by the recovery test with cerebrospinal fluid as real sample which resulted from 91.7% to 106.5%.     

在雨中飞奔

~~在雨中飞奔@小Q     

Construction and operation of a microrobot based on magnetotactic bacteria in a microfluidic chip

Magnetotactic bacteria (MTB) are capable of swimming along magnetic field lines. This unique feature renders them suitable in the development of magnetic-guided, auto-propelled microrobots to serve in target molecule separation and detection, drug delivery, or target cell screening in a microfluidic chip. The biotechnology to couple these bacteria with functional loads to form microrobots is the critical point in its application. Although an immunoreaction approach to attach functional loads to intact MTB was suggested, details on its realization were hardly mentioned. In the current paper, MTB-microrobots were constructed by attaching 2 μm diameter microbeads to marine magnetotactic ovoid MO-1 cells through immunoreactions. These microrobots were controlled using a special control and tracking system. Experimental results prove that the attachment efficiency can be improved to ∼30% via an immunoreaction. The motility of the bacteria attached with different number of loads was also assessed. The results show that MTB can transport one load at a velocity of ∼21 μm/s and still move and survive for over 30 min. The control and tracking system is fully capable of directing and monitoring the movement of the MTB-microrobots. The rotating magnetic fields can stop the microrobots by trapping them as they swim within a circular field with a controllable size. The system has potential use in chemical analyses and medical diagnoses using biochips as well as in nano/microscale transport.     

星座9月运势

从本月起,我们特地请来国外星座专家,为您提供每月星座运势,还可以顺便学习星座英语哦！     

星座10月运势

本月主打星座——处女座（8．24～9．23）。处女座是追求完美的星座,做事一丝不苟,有强烈的批判精神。极度厌恶虚伪与不正当的事。谦虚、理性、高智商、高财商的处女座往往是优秀的主管,能够在企业中起带头作用。     

Characterization of a bioflocculant from a newly isolated Vagococcus sp. W31

INTRODUCTION Bioflocculation is a dynamic process resulting from the synthesis of extracellular polymer by living cells. Since flocculation in microbial system was first reported by Louis Pasteur (Salehizadeh and Sho-jaosadati, 2001), bioflocculation has been investi-gated extensively and a correlation was established between the accumulation of extracellular biofloccu-lants and cell aggregation (Tenney and Verhoff, 1973). Bioflocculants are essentially polymers pro-duced by microorgan…     

Science Letters：IGFBP7 plays a potential tumor suppressor role against colorectal carcinogenesis with its expression associated with DNA hypomethylation of exon 1

Insulin-like growth factor binding-protein-7 （IGFBP7） was obtained from our previous colonic adenocarcinoma （CRC） and normal mucosa suppression subtraction hybridization （SSH） cDNA libraries. By RT-PCR and immunohistochemistry, we found that IGFBP7 was overexpressed in CRC tissue compared to normal tissue. However, our in vitro experiments performed in 10 CRC cell lines showed that IGFBP7 expressed only in SW480 and Caco2 cell lines, which implied an underlying reversible regulatory mechanism. Using methylation-specific PCR （MSP） and bisulfite sodium PCR （BSP）, we found that its expression was associated with DNA hypomethylation of exonl. This was further supported by the in vitro study which showed restored IGFBP7 expression after demethylation agent 5-aza-2＇-deoxycytidine treatment. Correlation analysis between IGFBP7 expression and prognosis indicated that overexpression of IGFBP7 in CRC tissue correlated with favourable survival. Investigation of the functional role of IGFBP7 through transfection studies showed that IGFBP7 protein could inhibit growth rate, decrease colony formation activity, and induce apoptosis in RKO and SW620 cells, suggesting it a potential tumor suppressor protein in colorectal carcinogenesis. In conclusion, our study clearly demonstrated that IGFBP7 plays a potential tumor suppressor role against colorectal carcinogenesis and its expression is associated with DNA hypomethylation of exon 1.     

Relations among positive parenting, children's effortful control, and externalizing problems: a three-wave longitudinal study

In a 3-wave longitudinal study (with assessments 2 years apart) involving 186 early adolescents (M ages of approximately 9.3, 11.4, and 13.4), the hypothesis that parental warmth/positive expressivity predicts children's effortful control (EC) (a temperamental characteristic contributing to emotion regulation) 2 years later, which in turn predicts low levels of externalizing problems another 2 years later, was examined. The hypothesis that children's EC predicts parenting over time was also examined. Parents were observed interacting with their children; parents and teachers reported children's EC and externalizing problems; and children's persistence was assessed behaviorally. Children's EC mediated the relation between positive parenting and low levels of externalizing problems (whereas there was no evidence that children's EC predicted parenting).     

夏日肌肤“驻”水秘笈Let''''s go masking

夏季的到来,千万不可让猛烈的阳光肆虐肌肤,令其变得干燥及出现恼人的黑斑。除了涂用美白乳霜外;要得到最显著而即时的效果,便是选用具美白成分的面膜。要加强美白效果,便要选择含多种维他命及纯天然矿物质成分的面膜,例如含有脂溶性维生素C,有助排除及分解黑色素的积聚,防止黑斑的产生,改善暗哑的肤色,并能为肌肤提供适当的润泽。     

宝宝辅食ABC

宝宝过满月了，宝宝过百日了，宝宝一天一天在妈妈的手掌心中长大，他对营养素的需求也在不断地变化，怎样适宜地为宝宝选择辅食添加成了妈妈最关心的问题，以下几点提议你可以作为参考。