500 research outputs found

    Low cost fabrication of microfluidic paper-based analytical devices with water-based polyurethane acrylate and their application for bacterial detection

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    This study presents a simple, inexpensive and environment-friendly fabrication strategy for microfluidic paper-based analytical devices which can resist the penetration of surfactant solutions and organic solvents, by using water-based polyurethane acrylate via UV light curing. The filter paper's barrier created using cured PUA could withstand surfactant solutions (10 wt%, CTAB, SDS and Triton X-100) and organic solvents (methanol, isopropanol, DMF, DMSO, etc). This is very useful for analyzing complicated biological samples on the microfluidic paper-based analytical devices. In addition, the expense of water-based polyurethane acrylate is very cheap (about $8/500 g) and PUA developer is water that is environmental-friendly. To further verify its advantage, we successfully demonstrated the proposed microfluidic devices for detection of E. coli targets in tap water and seawater via colorimetric analysis in a fast and convenient manner. Our results revealed that the linear response to E. coli BL21 was in the range of 10(4)similar to 10(9) cfu/mL. The proposed method can effectively avoid the damage for the hydrophobic barriers from the solution even some aggressive liquids, and shows great potential in on-site analysis, environmental monitoring, and food safety

    Testing for Differentially-Expressed MicroRNAs with Errors-in-Variables Nonparametric Regression

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    MicroRNA is a set of small RNA molecules mediating gene expression at post-transcriptional/translational levels. Most of well-established high throughput discovery platforms, such as microarray, real time quantitative PCR, and sequencing, have been adapted to study microRNA in various human diseases. The total number of microRNAs in humans is approximately 1,800, which challenges some analytical methodologies requiring a large number of entries. Unlike messenger RNA, the majority of microRNA (60%) maintains relatively low abundance in the cells. When analyzed using microarray, the signals of these low-expressed microRNAs are influenced by other non-specific signals including the background noise. It is crucial to distinguish the true microRNA signals from measurement errors in microRNA array data analysis. In this study, we propose a novel measurement error model-based normalization method and differentially-expressed microRNA detection method for microRNA profiling data acquired from locked nucleic acids (LNA) microRNA array. Compared with some existing methods, the proposed method significantly improves the detection among low-expressed microRNAs when assessed by quantitative real-time PCR assay

    Proteomic Analysis of Rat Hypothalamus Revealed the Role of Ubiquitin–Proteasome System in the Genesis of DR or DIO

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    Obesity has become a global epidemic, contributing to the increasing burdens of cardiovascular disease and type 2 diabetes. However, the precise molecular mechanisms of obesity remain poorly elucidated. The hypothalamus plays a major part in regulating energy homeostasis by integrating all kinds of nutritional signals. This study investigated the hypothalamus protein profile in diet-induced obese (DIO) and diet-resistant (DR) rats using two dimensional gel electrophoresis (2-DE) combined with MALDI-TOF/TOF–MS analysis. Twenty-two proteins were identified in the hypothalamus of DIO or DR rats. These include metabolic enzymes, antioxidant proteins, proteasome related proteins, and signaling proteins, some of which are related to AMP-activated protein kinase (AMPK) signaling or mitochondrial respiration. Among these proteins, in comparison with the normal-diet group, Ubiquitin was significantly decreased in DR rats but not changed in DIO rats, while Ubiquitin carboxyl-terminal esterase L1 (UCHL-1) was decreased in DIO rats but not changed in DR rats. The expression level of Ubiquitin and UCHL-1 were further validated using Western blot analysis. Our study reveals that Ubiquitin and UCHL-1 are obesity-related factors in the hypothalamus that may play an important role in the genesis of DR or DIO by interfering with the integrated signaling network that control energy balance and feeding

    Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay

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    The decay channel ψπ+πJ/ψ(J/ψγppˉ)\psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) is studied using a sample of 1.06×1081.06\times 10^8 ψ\psi^\prime events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the ppˉp\bar{p} invariant mass spectrum. The enhancement can be fit with an SS-wave Breit-Wigner resonance function with a resulting peak mass of M=186113+6(stat)26+7(syst)MeV/c2M=1861^{+6}_{-13} {\rm (stat)}^{+7}_{-26} {\rm (syst)} {\rm MeV/}c^2 and a narrow width that is Γ<38MeV/c2\Gamma<38 {\rm MeV/}c^2 at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics

    The Participation of Calponin in the Cross Talk between 20-Hydroxyecdysone and Juvenile Hormone Signaling Pathways by Phosphorylation Variation

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    20-hydroxyecdysone (20E) and juvenile hormone (JH) signaling pathways interact to mediate insect development, but the mechanism of this interaction is poorly understood. Here, a calponin homologue domain (Chd) containing protein (HaCal) is reported to play a key role in the cross talk between 20E and JH signaling by varying its phosphorylation. Chd is known as an actin binding domain present in many proteins including some signaling proteins. Using an epidermal cell line (HaEpi), HaCal was found to be up-regulated by either 20E or the JH analog methoprene (JHA). 20E induced rapid phosphorylation of HaCal whereas no phosphorylation occurred with JHA. HaCal could be quickly translocated into the nuclei through 20E or JH signaling but interacted with USP1 only under the mediation of JHA. Knockdown of HaCal by RNAi blocked the 20E inducibility of USP1, PKC and HR3, and also blocked the JHA inducibility of USP1, PKC and JHi. After gene silencing of HaCal by ingestion of dsHaCal expressed by Escherichia coli, the larval development was arrested and the gene expression of USP1, PKC, HR3 and JHi were blocked. These composite data suggest that HaCal plays roles in hormonal signaling by quickly transferring into nucleus to function as a phosphorylated form in the 20E pathway and as a non-phosphorylated form interacting with USP1 in the JH pathway to facilitate 20E or JH signaling cascade, in short, by switching its phosphorylation status to regulate insect development
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