Detection of Microcystin-Producing Cyanobacteria in a Reservoir by Whole Cell Quantitative PCR

AbstractCyanobacterial blooms are of increasing concern due to their negative impacts on environment and cyanobacteria-producing cyanotoxins, which create serious threats to animal and human health. Early detection of the harmful cyanotoxin-producing cyanobacteria is vital for the water management. In this study, we compared the amplification specificity for microcystin-producing cyanobacteria with primers targeting 16S rRNA genes, phycocyanin operon, and regions of mcy gene clusters. To detect presence of microcystin-producing cyanobacteria in a drinking water sourced reservoir, whole cell PCR assay was performed to amplify partial mcyA, mcyE, and the results were compared with that of direct microscopic counts based on morphologic identification. The positive liner correlation of the Microcystis colony by microscopic counts with mcyA containing cell, which was quantified by whole cell quantitative RT-PCR assay, was further confirmed. The results indicated that the microcystin-producer in the reservoir was mainly Microcystis. Therefore, we provided a simple, rapid, sensitive and applicable method for early detection of toxic cyanobacteria

Weak antilocalization and electron-electron interaction in coupled multiple-channel transport in a Bi2_2Se3_3 thin film

Electron transport properties of a topological insulator Bi$_2$Se$_3$ thin film are studied in Hall-bar geometry. The film with a thickness of 10 nm is grown by van der Waals epitaxy on fluorophlogopite mica and Hall-bar devices are fabricated from the as-grown film directly on the mica substrate. Weak antilocalization and electron-electron interaction effects are observed and analyzed at low temperatures. The phase-coherence length extracted from the measured weak antilocalization characteristics shows a strong power-law increase with decreasing temperature and the transport in the film is shown to occur via coupled multiple (topological surface and bulk states) channels. The conductivity of the film shows a logarithmically decrease with decreasing temperature and thus the electron-electron interaction plays a dominant role in quantum corrections to the conductivity of the film at low temperatures.Comment: 12 pages, 5 figure

Physics-driven Deep Learning Inversion for Direct Current Resistivity Survey Data

The direct-current (DC) resistivity method is a commonly used geophysical technique for surveying adverse geological conditions. Inversion can reconstruct the resistivity model from data, which is an important step in the geophysical survey. However, the inverse problem is a serious ill-posed problem that makes it easy to obtain incorrect inversion results. Deep learning (DL) provides new avenues for solving inverse problems, and has been widely studied. Currently, most DL inversion methods for resistivity are purely data-driven and depend heavily on labels (real resistivity models). However, real resistivity models are difficult to obtain through field surveys. An inversion network may not be effectively trained without labels. In this study, we built an unsupervised learning resistivity inversion scheme based on the physical law of electric field propagation. First, a forward modeling process was embedded into the network training, which converted the predicted model to predicted data and formed a data misfit to the observation data. Unsupervised training independent of the real model was realized using the data misfit as a loss function. Moreover, a dynamic smoothing constraint was imposed on the loss function to alleviate the ill-posed inverse problem. Finally, a transfer learning scheme was applied to adapt the trained network with simulated data to field data. Numerical simulations and field tests showed that the proposed method can accurately locate and depict geological targets

Chronic CSE Treatment Induces the Growth of Normal Oral Keratinocytes via PDK2 Upregulation, Increased Glycolysis and HIF1α Stabilization

Exposure to cigarette smoke is a major risk factor for head and neck squamous cell carcinoma (HNSCC). We have previously established a chronic cigarette smoke extract (CSE)-treated human oral normal keratinocyte model, demonstrating an elevated frequency of mitochondrial mutations in CSE treated cells. Using this model we further characterized the mechanism by which chronic CSE treatment induces increased cellular proliferation.We demonstrate that chronic CSE treatment upregulates PDK2 expression, decreases PDH activity and thereby increases the glycolytic metabolites pyruvate and lactate. We also found that the chronic CSE treatment enhanced HIF1α accumulation through increased pyruvate and lactate production in a manner selectively reversible by ascorbate. Use of a HIF1α small molecule inhibitor blocked the growth induced by chronic CSE treatment in OKF6 cells. Furthermore, chronic CSE treatment was found to increase ROS (reactive oxygen species) production, and application of the ROS scavengers N-acetylcysteine abrogated the expression of PDK2 and HIF1α. Notably, treatment with dichloroacetate, a PDK2 inhibitor, also decreased the HIF1α expression as well as cell proliferation in chronic CSE treated OKF6 cells.Our findings suggest that chronic CSE treatment contribute to cell growth via increased ROS production through mitochondrial mutations, upregulation of PDK2, attenuating PDH activity thereby increasing glycolytic metabolites, resulting in HIF1α stabilization. This study suggests a role for chronic tobacco exposure in the development of aerobic glycolysis and normoxic HIFα activation as a part of HNSCC initiation. These data may provide insights into development of chemopreventive strategies for smoking related cancers

The Poverty Alleviation and Immigration Practice Model Effect Research in Liulin

Abstract By the way of field investigation and statistical analysis, I have carried on investigation to Liulin, migrant village and I have learnt something about migration forms, mainly interaction patterns of villages and towns aggregation model. This article mainly analyzes the work and the necessity of immigration for poverty alleviation and the actual effect of the two modes in Lilulin. Moreover, I put forward some suggestions to model improvement and hope that I can do some useful things to poverty reduction in Liulin. At the same time, it can provide favorable help for building a harmonious society