In Vitro, Non-Invasive Imaging and Detection of Single Living Mammalian Cells Interacting with Bio-Nano-Interfaces

Understanding of bio-nano-interfaces of living mammalian cells will benefit the identification of cellular alterations (e.g. nucleic acids, amino acids, biomechanics, etc.) due to external stimuli, the design of biomaterials (e.g. nanoparticles, nanotubes) and the investigation of the interaction between cells and bio-nano-interfaces (e.g. cell differentiation on 3D nanostructured materials). Analytical techniques can be applied to evaluate the chemical, physical, and mechanical properties of mammalian cells when exposed to such bio-nano-interfaces. In this study, non-invasive advanced spectroscopy techniques including atomic force microscopy (AFM) and Raman microscopy (RM), in conjunction with traditional biological methods are utilized to elucidate specific characteristic information for biological samples and how these property changes reflect the interaction with external stimuli. The focus of this dissertation is on the biophysical, biochemical and cytotoxic detection of mammalian cells interacting with bio-nano-interfaces, and this dissertation can be classified into three topics: biomechanics/cellular biopolymers measurement, bio-interfaces and nano-interfaces studies. For the topic of biomechanics/cellular biopolymers measurement, cellular biophysical and biomechanical properties could be used as differentiation markers to classify cellular differentiation. For the bio-interfaces part, it was observed that BRMS1 expression changed cellular biochemical and biomechanical properties, and the expressions of reactive oxidative species (ROS), apoptosis and cell viability of five types of cells displayed similar patterns over doxorubicin (DOX) incubation time. Secondly, A549 cells were treated with diesel exhaust particles (DEP) and resveratrol (RES) to study the effect of RES on the DEP-induced cells, and it was found that RES can alleviate DEP intervention on cellular structure and increase DEP-induced biomechanical and inflammatory changes. For the nano-interfaces topic, first we synthesized a hybrid nanoparticle with the multimodal properties of fluorescence imaging, Surface-enhanced Raman spectroscopy (SERS) detection and photothermal therapy (PTT) for single living cell analysis of epidermal growth factor receptor (EGFR) and specifically killed cancer cells with high EGFR expression. Additionally, to increase surface area, light-heat conversion efficiency and biocompatibility, we developed a silica coated nanoparticle conjugated with anti-human epidermal growth factor receptor 2 (HER2) antibody. Finally, three-dimensional TiO2 nanotubes with Au nanoparticles coating were synthesized and used to study trophoblast-derived stem-like cells growth on such 3D nanostructures

Solid-liquid Two-phase Flow Numerical Simulation around Guide Vanes of Mixed-flow Water Turbine

AbstractBased on the N-S control equation and κ-ɛ-Ap turbulent model, the solid-liquid two-phase flow field around the guide vanes of a mixed-flow water turbine was simulated. The solid-liquid two-phase flow characters around the guide vanes were analyzed on the design work condition with different volume fraction and particles diameter of solid phase. The effects of the solid particles diameter and volume fraction on the flow around the guide vane are discussed, based on which the prediction and analysis of abrasion and cavitation properties on the guiding device were given. The prediction results were identical with the test date, which can provide reference on the abrasion prediction and optimal design of guide vane

Projected Spatiotemporal Dynamics of Drought under Global Warming in Central Asia

Drought, one of the most common natural disasters that have the greatest impact on human social life, has been extremely challenging to accurately assess and predict. With global warming, it has become more important to make accurate drought predictions and assessments. In this study, based on climate model data provided by the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP), we used the Palmer Drought Severity Index (PDSI) to analyze and project drought characteristics and their trends under two global warming scenarios—1.5 °C and 2.0 °C—in Central Asia. The results showed a marked decline in the PDSI in Central Asia under the influence of global warming, indicating that the drought situation in Central Asia would further worsen under both warming scenarios. Under the 1.5 °C warming scenario, the PDSI in Central Asia decreased first and then increased, and the change time was around 2080, while the PDSI values showed a continuous decline after 2025 in the 2.0 °C warming scenario. Under the two warming scenarios, the spatial characteristics of dry and wet areas in Central Asia are projected to change significantly in the future. In the 1.5 °C warming scenario, the frequency of drought and the proportion of arid areas in Central Asia were significantly higher than those under the 2.0 °C warming scenario. Using the Thornthwaite (TH) formula to calculate the PDSI produced an overestimation of drought, and the Penman–Monteith (PM) formula is therefore recommended to calculate the index

Optimal remanufacturing strategies in name-your-own-price auctions with limited capacity

We study optimal pricing and production strategies faced by a manufacturer in a remanufacturing/manufacturing system. In the reverse channel, returns are collected under a name-your-own-price (NYOP) bidding mechanism. The manufacturer has a limited capacity to produce new and remanufactured products. We characterize the optimal decisions of the consumers and the manufacturer. We find that under the NYOP mechanism, the manufacturer׳s optimal strategies mainly depend on the bidding cost, the cost saving of remanufacturing, the production capacity, and the market scale. In addition, when remanufacturing needs more capacity than manufacturing , the manufacturer may adopt pure manufacturing strategy without remanufacturing. We also compare this mechanism with the traditional list-price mechanism and find that the manufacturer prefers the NYOP mechanism under the conditions of a low reverse market share, a high manufacturing cost, a sufficient capacity, or a low capacity requirement of remanufacturing. Numerical studies investigate the effect of key parameters on the manufacturer׳s profit and some managerial insights are obtained

Infection of hepatitis B virus in extrahepatic endothelial tissues mediated by endothelial progenitor cells

BACKGROUND: Hepatitis B virus (HBV) replication has been reported to be involved in many extrahepatic viral disorders; however, the mechanism by which HBV is trans-infected into extrahepatic tissues such as HBV associated myocarditis remains largely unknown. RESULTS: In this study, we showed that human cord blood endothelial progenitor cells (EPCs), but not human umbilical vein endothelial cells (HUVECs) could be effectively infected by uptake of HBV in vitro. Exposure of EPCs with HBV resulted in HBV DNA and viral particles were detected in EPCs at day 3 after HBV challenge, which were peaked around day 7 and declined in 3 weeks. Consistently, HBV envelope surface and core antigens were first detected in EPCs at day 3 after virus challenge and were retained to be detectable for 3 weeks. In contrast, HBV covalently closed circular DNA was not detected in EPCs at any time after virus challenge. Intravenous transplantation of HBV-treated EPCs into myocardial infarction and acute renal ischemia mouse model resulted in incorporation of HBV into injured heart, lung, and renal capillary endothelial tissues. CONCLUSION: These results strongly support that EPCs serve as virus carrier mediating HBV trans-infection into the injured endothelial tissues. The findings might provide a novel mechanism for HBV-associated myocarditis and other HBV-related extrahepatic diseases as well

Preparation of desulfurizing activated carbon from corn stalk and characterization of desulfurizing structure

This study investigated the optimal conditions for preparing desulfurizing stalk carbon, using corn stalk as a raw material and zinc chloride as an activator. The structure of stalk carbon was characterized using thermogravimetry (TG), fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Brunauer – Emmelt – Teller (BET). Results found no significant difference in stalk carbon desulfurization properties when using stalk skin, core, or a skin-core mixture as raw material. The desulfurization performance of stalk carbon prepared using a skin-core mixture, was the most effective when the material : liquid ratio was 1:2; activation temperature was 350 °C; and activation time was 70 min. The corresponding H2S adsorption time was 74 min. The large specific surface area of 562.28 m2/g and abundant pore-volume of 0.3851 ml/g was found in the desulfurization stalk carbon prepared using these conditions. The increase in micropores and the abundant oxygen-containing functional surface groups were conducive to H2S adsorption. The desulfurization products were found to be mainly elemental S and sulfite