Rational design and performance testing of aptamer-based electrochemical biosensors for adenosine

This work emphasizes on the design criteria of aptamer-based biosensors for adenosine and the comparison of their performances by using both electrochemical and biochemical methods. The adenosine biosensors have been typically prepared by hybridizing a short bridging DNA (modified with a thiol for the attachment to gold electrode) to the aptamer strand that releases upon adenosine binding. We have carefully compared the two “isomeric” designs, one with the thiol-linker tethered to the 3′-hydroxyl and the other to the 5′-phosphate end of the bridging DNA. It has been demonstrated through electrochemical and gel electrophoresis experiments that the 3′-thiol bridged sensor shows much better performance than its 5′-counterpart on surface, whereas in solution phase the two sensor systems are equally sensitive. We believe that the “transient” secondary structure of the aptamer sequence restricts the freedom of the strand displacement upon analyte binding, leading to a sluggish release of the aptamer strand from the 5′-thiol-bridging DNA.     

Mice with deleted multimerin 1 and α-synuclein genes have impaired platelet adhesion and impaired thrombus formation that is corrected by multimerin 1

Background

Multimerin 1 is a stored platelet and endothelial cell adhesive protein that shows significant conservation. In vitro, multimerin 1 supports platelet adhesion and it also binds to collagen and enhances von Willebrand factor-dependent platelet adhesion to collagen. As selective, multimerin 1 deficient mice have not been generated, we investigated multimerin 1 effects on platelet adhesion using a subpopulation of C57BL/6J mice with tandem deletion of the genes for multimerin 1 and α-synuclein, a protein that inhibits α-granule release in vitro. We postulated that multimerin 1/α-synuclein deficient mice might show impaired platelet adhesive function from multimerin 1 deficiency and increased α-granule release from α-synuclein deficiency.

Methods

Platelet function was assessed by intravital microscopy, after ferric chloride injury, using untreated and human multimerin 1-transfused multimerin 1/α-synuclein deficient mice, and by in vitro assays of adhesion, aggregation and thrombin-induced P-selectin release.

Results

Multimerin 1/α-synuclein deficient mice showed impaired platelet adhesion and their defective thrombus formation at sites of vessel injury improved with multimerin 1 transfusion. Although multimerin 1/α-synuclein deficient platelets showed increased P-selectin release at low thrombin concentrations, they also showed impaired adhesion to collagen, and attenuated aggregation with thrombin, that improved with added multimerin 1.

Conclusions

Our data suggest that multimerin 1 supports platelet adhesive functions and thrombus formation, which will be important to verify by generating and testing selective multimerin 1 deficient mice.     

The neural substrates for atypical planning and execution of word production in stuttering

Using an fMRI-based classification approach and the structural equation modeling (SEM) method, this study examined the neural bases of atypical planning and execution processes involved in stuttering. Twelve stuttering speakers and 12 controls were asked to name pictures under different conditions (single-syllable, multi-syllable, or repeated-syllable) in the scanner. The contrasts between conditions provided information about planning and execution processes. The classification analysis showed that, as compared to non-stuttering controls, stuttering speakers’ atypical planning of speech was evident in their neural activities in the bilateral inferior frontal gyrus (IFG) and right putamen and their atypical execution of speech was evident in their activations in the right cerebellum and insula, left premotor area (PMA), and angular gyrus (AG). SEM results further revealed two parallel neural circuits—the basal ganglia-IFG/PMA circuit and the cerebellum-PMA circuit—that were involved in atypical planning and execution processes of stuttering, respectively. The AG appeared to be involved in the interface of atypical planning and execution in stuttering. These results are discussed in terms of their implications to the theories about stuttering and to clinical applications.     

锑膜修饰电极差分脉冲溶出伏安法测定痕量锡

目的:建立一种新的快速检测方法测定实际样品中的Sn。方法:采用同位镀锑膜玻碳电极,利用差分脉冲溶出伏安法对痕量Sn进行测定。结果:优化实验条件下,相关性好(r>0.99),测得Sn2+的线性范围和最低检出限分别为10~120μg/L和0.50μg/L,样品加标回收率为96%~98%。结论:锑膜电极可成为继铋膜电极之后又一种新的环保型膜电极,用于实际样品中重金属的检测。     

方阵式PCR在大肠埃希菌O157检测中的成本效益分析

目的:探讨一种检测O157的经济适用的检测方法。方法:把100个待检样品排成10×10方阵,对方阵中的每排,每列样品混合为一个新的样品,对混合样品进行O157的PCR检测。结果:PCR与方阵相结合,比传统检测方式节省约80%的检测成本,而且能快速准确定位目的菌。结论:PCR与方阵相结合是一种经济有效的检测方法,值得在大样本量的检测工作中推广。     

Exotic Dance in Baltimore: From Entry to STI/HIV Risk

Research has documented health risks associated with sex work, but few U.S. studies have focused on the exotic dance industry. We undertook this study to describe the factors that influenced women’s entry into exotic dance and explored the relation of these forces to their subsequent sexually transmitted infection (STI)/HIV risk trajectory. Qualitative interviews (N = 25) were conducted with female exotic dancers from June through August 2009. Data were analyzed through Atlas-ti using an inductive approach. Economic vulnerability was the primary force behind women’s initiation into the profession. Drug use, physical abuse, and enjoyment of dancing were often concurrent with economic need and provided a further push toward exotic dance. Social networks facilitated entry by normalizing the profession and presenting it as a solution to financial hardship. Characteristics of exotic dance clubs, such as immediate hire and daily pay, attracted women in a state of financial vulnerability. Women’s motivations for dancing, including economic vulnerability and drug use practices, shaped their STI/HIV risk once immersed in the club environment, with social networks often facilitating sexual risk behavior. Understanding the factors that drive women to exotic dance and influence risk behavior in the club may assist in the development of targeted harm reduction interventions for exotic dancers.