Friction and wear behaviors of a high nitrogen austenitic stainless steel Fe-19Cr-15Mn-0.66N

The friction and wear behaviors of a Fe-19Cr-15Mn-0.66N high nitrogen austenitic stainless steel (HNSS) were investigated. Tribological investigations were carried out under different applied loads of 5 N, 10 N, 15 N and 20 N. Scanning electron microscope (SEM) and laser scanning confocal microscope (LSCM) were used to understand the wear mechanisms under different loads and the reasons for the improved wear resistance. The lower friction coefficient and improved wear resistance were observed with the increase in applied loads. Under a higher load, the friction enhanced the work hardening ability of HNSS, which in turn improved its surface hardness and thus the increased wear resistance of HNSS.

3D imaging of ZnO NP distribution and ROS accumulation in MCF-7 cells and quantification of retention dynamics using laser scanning confocal microscopy

Generally, investigations on nanomedicine involve conventional imaging techniques for obtaining static images on nanoparticle internalization at a single time point where various phases can be overlooked. In contrast, 3D live-cell imaging can be used for obtaining cellular retention of drugs at various phases, and cells can be followed for days. This article demonstrates the application of time-lapse microscopy in the investigation of Poly-L-lysine coated ZnO nanoparticle dynamics. In this work, a laser scanning confocal microscope has been employed to quantify the dynamics of internalization particles and reactive oxygen species generation (ROS) using volumetric imaging. Firstly, we show that simultaneous spatial mapping of nanoparticle uptake in MCF-7 cells and ROS in a single cell can be used to identify the interdependence between the accumulation of particles and ROS generation. Secondly, monitoring of ROS formation and cytotoxicity using the same imaging platform offers an advantage over monitoring these parameters using various instruments. Finally, the ability of the fluorescent particles in inducing a significant reduction in cell viability suggests its potential to be used as a therapeutic agent. The proposed framework opens up a new avenue of research for investigating mechanistic aspects of ZnO particle adsorption in vitro through long term imaging. Keywords: Fluorescent ZnO particle, Time-lapse microscopy, 3D Live-cell imaging, laser scanning confocal microscope, Reactive oxygen species

FUT4siRNA augments the chemosensitivity of non-small cell lung cancer to cisplatin through activation of FOXO1-induced apoptosis

Background Increased fucosylation is associated with the chemoresistance phenotype. Meanwhile, fucosyltransferase IV (FUT4) amounts are frequently elevated in lung cancer and may be related to increased chemoresistance. Methods In the present work, FUT4’s role in cisplatin-induced apoptosis was assessed in A549 and H1975 cells, respectively. To clarify whether the FUT4 gene attenuates chemosensitivity in tumor cells, we constructed FUT4siRNA and evaluated its effects on cisplatin-induced apoptosis and cell growth inhibition. Cell viability, apoptosis, migration and invasion assay were conducted to investigate cisplatin sensitivity. The activation of EGFR/AKT/FOXO1 signaling were measured by western blot. The translocation of FOXO1 was assessed by IFC using Laser Scanning Confocal Microscope. Results We found that FUT4 knockdown dose-dependently increased cisplatin-associated cytotoxicity. Furthermore, FUT4 silencing induced apoptosis and inhibited proliferation in A549 and H1975 cells by suppressing Akt and FOXO1 phosphorylation induced by cisplatin administration, which resulted in nuclear translocation of FOXO1. Conclusion These results suggested FUT4 might control chemoresistance to cisplatin in lung cancer by suppressing FOXO1-induced apoptosis.

Catalytic etching of {100}-oriented diamond coating with Ni and Cu nanoparticles under hydrogen

Nanopores formed in insulating solid state membrane is of great importance in many fields such as detection of DNA/RNA molecules in their internal environment, probing and manipulating biopolymers. Here, we present an effective and convenient method to form nanopores in diamond etched by self-assembled Ni or Cu nanoparticles in hydrogen atmosphere. With our method, homogeneous nanopores with lateral size in the range of [Formula: see text]–[Formula: see text] were created without using Reactive Ion Etching (RIE) process. In this work, the etching pits of Ni and Cu etched diamond were investigated, respectively. A novel step-like pattern of etching pits was observed on diamond etched by Ni. In order to study the etching process and figure out the etching mechanism of diamond, Scanning Electron Microscopy (SEM) was used to observe the etching morphology. Atomic Force Microscopy (AFM) and Laser Scanning Confocal Microscope (LSCM) were used to visualize the image of diamond etching pits and investigate the step-like pattern. A fixed step height was observed in each pit. Based on these observations and findings, a hypothesis is proposed, which can help to provide a new controllable etching method.

Detection and quantification of microplastic in soils using a 3D Laser Scanning Confocal Microscope

<p>There is growing concern regarding the pollution of our environment with plastic materials, whereas especially the dimension of microplastic pollution and its ecological effect is widely discussed. Most studies focus on aquatic environments, while studies in terrestrial systems (mainly soils) are rare. This partly results from the challenges arising when microplastic particles need to be separated from organic and mineral particles. Key analytic techniques for microplastic detection in aquatic and terrestrial systems include Fourier transformation-infrared (FT-IR) and micro-Raman spectroscopy, as well as thermal extraction desorption-gas chromatography-mass spectrometry (TED-GC-MS) and pyrolysis-gas chromatography-mass spectrometry (pyr-GC-MS). While the mass spectrometric methods lack to determine particle sizes, the FT-IR and micro-Raman spectroscopy are very costly and time consuming. Moreover, the latter detection methods are very sensitive to organic matter particles, which are difficult to remove fully during soil sample preparation. Hence, a faster and more robust method to determine microplastic in soils is essential for a wider analysis of this environmental problem. In this study, we combine a density separation scheme with a 3D Laser Scanning Confocal Microscope (Keyence VK-X1000, Japan) analysis to determine the number and size of microplastic particles in soil samples. For the analysis a silty loam (16% sand, 59% silt, 25% clay, 1.3% organic carbon) and a loamy sand (72% sand, 18% silt, 10% clay, 0.9% organic carbon) were spiked with different concentrations of high density Polyethylene (HDPE), low density Polyethylene (LDPE) and Polystyrene (PS) microplastic (HDPE 50 - 100 and 250 - 300 µm, LDPE <50 and 200 - 800 µm, PS <100 µm). 3D Laser Scanning Confocal Microscopy show very promising results while using differences in optical characteristic and especially surface roughness, to distinguish between plastic and mineral as well as organic particles left after density separation. Overall, the 3D Laser Scanning Confocal Microscopy is a promising tool for relatively fast detection and quantification of microplastic in soils, which could perfectly complement the also relative fast mass-spectrometric methods to determine plastic types. However, to result in an operational and automated analyzation process further research based on the 3D Laser Scanning Confocal Microscopy analysis is needed.</p>